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Sample records for localized hole energy-level

  1. Local temperature for dynamical black holes

    NASA Astrophysics Data System (ADS)

    Hayward, Sean A.; di Criscienzo, R.; Nadalini, M.; Vanzo, L.; Zerbini, S.

    2009-05-01

    A local Hawking temperature was recently derived for any future outer trapping horizon in spherical symmetry, using a Hamilton-Jacobi tunneling method, and is given by a dynamical surface gravity as defined geometrically. Descriptions are given of the operational meaning of the temperature, in terms of what observers measure, and its relation to the usual Hawking temperature for static black holes. Implications for the final fate of an evaporating black hole are discussed.

  2. Black holes and local dark matter

    NASA Technical Reports Server (NTRS)

    Hegyi, D. J.; Kolb, E. W.; Olive, K. A.

    1986-01-01

    Two independent constraints are placed on the amount of dark matter in black holes contained in the galactic disk. First, gas accretion by black holes leads to X-ray emission which cannot exceed the observed soft X-ray background. Second, metals produced in stellar processes that lead to black hole formation cannot exceed the observed disk metal abundance. Based on these constraints, it appears unlikely that the missing disk mass could be contained in black holes. A consequence of this conclusion is that at least two different types of dark matter are needed to solve the various missing mass problems.

  3. Black Hole Instabilities and Local Penrose Inequalities

    NASA Astrophysics Data System (ADS)

    Figueras, Pau; Murata, Keiju; Reall, Harvey S.

    2015-01-01

    Various higher-dimensional black holes have been shown to be unstable by studying linearized gravitational perturbations. A simpler method for demonstrating instability is to find initial data that describes a small perturbation of the black hole and violates a Penrose inequality. We use the method to confirm the existence of the "ultraspinning" instability of Myers-Perry black holes. We also study black rings and show that "fat" black rings are unstable. We find no evidence of any rotationally symmetric instability of "thin" black rings.

  4. Local structure of numerically generated worm hole spacetime.

    NASA Astrophysics Data System (ADS)

    Siino, M.

    The author investigates the evolution of the apparent horizons in a numerically gererated worm hole spacetime. The behavior of the apparent horizons is affected by the dynamics of the matter field. By using the local mass of the system, he interprets the evolution of the worm hole structure.

  5. Local Operators in the Eternal Black Hole.

    PubMed

    Papadodimas, Kyriakos; Raju, Suvrat

    2015-11-20

    In the AdS/CFT correspondence, states obtained by Hamiltonian evolution of the thermofield doubled state are also dual to an eternal black-hole geometry, which is glued to the boundary with a time shift generated by a large diffeomorphism. We describe gauge-invariant relational observables that probe the black hole interior in these states and constrain their properties using effective field theory. By adapting recent versions of the information paradox we show that these observables are necessarily described by state-dependent bulk-boundary maps, which we construct explicitly. PMID:26636843

  6. Local Operators in the Eternal Black Hole.

    PubMed

    Papadodimas, Kyriakos; Raju, Suvrat

    2015-11-20

    In the AdS/CFT correspondence, states obtained by Hamiltonian evolution of the thermofield doubled state are also dual to an eternal black-hole geometry, which is glued to the boundary with a time shift generated by a large diffeomorphism. We describe gauge-invariant relational observables that probe the black hole interior in these states and constrain their properties using effective field theory. By adapting recent versions of the information paradox we show that these observables are necessarily described by state-dependent bulk-boundary maps, which we construct explicitly.

  7. Slant-hole collimator, dual mode sterotactic localization method

    DOEpatents

    Weisenberger, Andrew G.

    2002-01-01

    The use of a slant-hole collimator in the gamma camera of dual mode stereotactic localization apparatus allows the acquisition of a stereo pair of scintimammographic images without repositioning of the gamma camera between image acquisitions.

  8. Hole localization in molecular crystals from hybrid density functional theory.

    PubMed

    Sai, Na; Barbara, Paul F; Leung, Kevin

    2011-06-01

    We use first-principles computational methods to examine hole trapping in organic molecular crystals. We present a computational scheme based on the tuning of the fraction of exact exchange in hybrid density functional theory to eliminate the many-electron self-interaction error. With small organic molecules, we show that this scheme gives accurate descriptions of ionization and dimer dissociation. We demonstrate that the excess hole in perfect molecular crystals forms self-trapped molecular polarons. The predicted absolute ionization potentials of both localized and delocalized holes are consistent with experimental values.

  9. FAST TRACK COMMUNICATION: Local Hawking temperature for dynamical black holes

    NASA Astrophysics Data System (ADS)

    Hayward, S. A.; Di Criscienzo, R.; Nadalini, M.; Vanzo, L.; Zerbini, S.

    2009-03-01

    A local Hawking temperature is derived for any future outer trapping horizon in spherical symmetry, using a Hamilton Jacobi variant of the Parikh Wilczek tunneling method. It is given by a dynamical surface gravity as defined geometrically. The operational meaning of the temperature is that Kodama observers just outside the horizon measure an invariantly redshifted temperature, diverging at the horizon itself. In static, asymptotically flat cases, the Hawking temperature as usually defined by the Killing vector agrees in standard cases, but generally differs by a relative redshift factor between the horizon and infinity, this being the temperature measured by static observers at infinity. Likewise, the geometrical surface gravity reduces to the Newtonian surface gravity in the Newtonian limit, while the Killing definition instead reflects measurements at infinity. This may resolve a long-standing puzzle concerning the Hawking temperature for the extremal limit of the charged stringy black hole, namely that it is the local temperature which vanishes. In general, this confirms the quasi-stationary picture of black-hole evaporation in early stages. However, the geometrical surface gravity is generally not the surface gravity of a static black hole with the same parameters.

  10. Hole localization, water dissociation mechanisms, and band alignment at aqueous-titania interfaces

    NASA Astrophysics Data System (ADS)

    Lyons, John L.

    Photocatalytic water splitting is a promising method for generating clean energy, but materials that can efficiently act as photocatalysts are scarce. This is in part due to the fact that exposure to water can strongly alter semiconductor surfaces and therefore photocatalyst performance. Many materials are not stable in aqueous environments; in other cases, local changes in structure may occur, affecting energy-level alignment. Even in the simplest case, dynamic fluctuations modify the organization of interface water. Accounting for such effects requires knowledge of the dominant local structural motifs and also accurate semiconductor band-edge positions, making quantitative prediction of energy-level alignments computationally challenging. Here we employ a combined theoretical approach to study the structure, energy alignment, and hole localization at aqueous-titania interfaces. We calculate the explicit aqueous-semiconductor interface using ab initio molecular dynamics, which provides the fluctuating atomic structure, the extent of water dissociation, and the resulting electrostatic potential. For both anatase and rutile TiO2 we observe spontaneous water dissociation and re-association events that occur via distinct mechanisms. We also find a higher-density water layer occurring on anatase. In both cases, we find that the second monolayer of water plays a crucial role in controlling the extent of water dissociation. Using hybrid functional calculations, we then investigate the propensity for dissociated waters to stabilize photo-excited carriers, and compare the results of rutile and anatase aqueous interfaces. Finally, we use the GW approach from many-body perturbation theory to obtain the position of semiconductor band edges relative to the occupied 1b1 level and thus the redox levels of water, and examine how local structural modifications affect these offsets. This work was performed in collaboration with N. Kharche, M. Z. Ertem, J. T. Muckerman, and M. S

  11. The local hole revealed by galaxy counts and redshifts

    NASA Astrophysics Data System (ADS)

    Whitbourn, J. R.; Shanks, T.

    2014-01-01

    The redshifts of ≈250 000 galaxies are used to study the local hole and its associated peculiar velocities. The sample, compiled from the 6dF Galaxy Redshift Survey and Sloan Digital Sky Survey, provides wide sky coverage to a depth of ≈300 h-1 Mpc. We have therefore examined K- and r-limited galaxy redshift distributions and number counts to map the local density field. Comparing observed galaxy n(z) distributions to homogeneous models in three large regions of the high-latitude sky, we find evidence for underdensities ranging from ≈4-40 per cent in these regions to depths of ≈150 h-1 Mpc with the deepest underdensity being over the southern Galactic cap. Using the Galaxy and Mass Assembly survey, we then establish the normalization of galaxy counts at fainter magnitudes and thus confirm that the underdensity over all three fields at K < 12.5 is ≈15 ± 3 per cent. Finally, we further use redshift catalogues to map sky-averaged peculiar velocities over the same areas using the average redshift-magnitude, overline{z}(m), technique of Soneira. After accounting for the direct effect of the large-scale structure on overline{z}(m), we can then search for peculiar velocities. Taking all three regions into consideration, the data reject at the ≈4σ level the idea that we have recovered the cosmic microwave background rest frame in the volume probed. We therefore conclude that there is some consistent evidence from both counts and Hubble diagrams for a `local hole' with an ≈150 h-1 Mpc underdensity that deeper counts and redshifts in the northern Galactic cap suggest may extend to ≈300 h-1 Mpc.

  12. The galaxy luminosity function and the Local Hole

    NASA Astrophysics Data System (ADS)

    Whitbourn, J. R.; Shanks, T.

    2016-06-01

    In a previous study Whitbourn & Shanks have reported evidence for a local void underdense by ≈15 per cent extending to 150-300 h-1 Mpc around our position in the Southern Galactic Cap (SGC). Assuming a local luminosity function they modelled K- and r-limited number counts and redshift distributions in the 6dFGS/2MASS and SDSS redshift surveys and derived normalized n(z) ratios relative to the standard homogeneous cosmological model. Here we test further these results using maximum likelihood techniques that solve for the galaxy density distributions and the galaxy luminosity function simultaneously. We confirm the results from the previous analysis in terms of the number density distributions, indicating that our detection of the `Local Hole' in the SGC is robust to the assumption of either our previous, or newly estimated, luminosity functions. However, there are discrepancies with previously published K- and r-band luminosity functions. In particular the r-band luminosity function has a steeper faint end slope than the r0.1 results of Blanton et al. but is consistent with the r0.1 results of Montero-Dorta & Prada and Loveday et al.

  13. Gauge/ gravity correspondence, bulk locality and quantum black holes

    NASA Astrophysics Data System (ADS)

    Sarkar, Debajyoti

    The aim of this dissertation is threefold. We begin by the study of two parallel ideal cosmic strings in the presence of non-minimal scalar fields and spin- 1 gauge fields. We show that the contributions of the non-minimal term on the interaction energy between the strings are similar to that of the gauge field for a particular value of non-minimal coupling parameter. In this context we clarify some of the issues that arise when comparing the renormalization of black hole entropy and entanglement entropy using the replica trick. In the second part of the dissertation we study the process of bound state formation in clusters of Dp- brane collision and Dp shell/ Membrane collapse processes. We consider two mechanisms for bound state formation. The first, operative at weak coupling in the worldvolume gauge theory, is creation of W-bosons. The second, operative at strong coupling, corresponds to formation of a black hole in the dual supergravity. These two processes agree qualitatively at intermediate coupling, in accord with the correspondence principle of Horowitz and Polchinski. We show that the size of the bound state and timescale for formation of a bound state agree at the correspondence point, along with other relevant thermodynamic quantities. The timescale involves matching a parametric resonance in the gauge theory to a quasinormal mode in supergravity. Finally we study construction of local operators in AdS using the generalized AdS/ CFT correspondence. After briefly sketching previous works on this topic which involve massless and massive scalar fields, we present similar construction for spin- 1 and spin- 2 gauge fields. Working in holographic gauge in the bulk, at leading order in 1/N bulk gauge fields are obtained by smearing boundary currents over a sphere on the complexified boundary, while linearized metric fluctuations are obtained by smearing the boundary stress tensor over a ball. This representation respects AdS covariance up to a compensating

  14. The black hole mass function derived from local spiral galaxies

    SciTech Connect

    Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Daniel; Kennefick, Julia; Seigar, Marc S.; Lacy, Claud H. S.; Hartley, Matthew T.

    2014-07-10

    We present our determination of the nuclear supermassive black hole (SMBH) mass function for spiral galaxies in the local universe, established from a volume-limited sample consisting of a statistically complete collection of the brightest spiral galaxies in the southern (δ < 0°) hemisphere. Our SMBH mass function agrees well at the high-mass end with previous values given in the literature. At the low-mass end, inconsistencies exist in previous works that still need to be resolved, but our work is more in line with expectations based on modeling of black hole evolution. This low-mass end of the spectrum is critical to our understanding of the mass function and evolution of black holes since the epoch of maximum quasar activity. The sample is defined by a limiting luminosity (redshift-independent) distance, D{sub L} = 25.4 Mpc (z = 0.00572) and a limiting absolute B-band magnitude, M{sub B}=−19.12. These limits define a sample of 140 spiral galaxies, with 128 measurable pitch angles to establish the pitch angle distribution for this sample. This pitch-angle distribution function may be useful in the study of the morphology of late-type galaxies. We then use an established relationship between the logarithmic spiral arm pitch angle and the mass of the central SMBH in a host galaxy in order to estimate the mass of the 128 respective SMBHs in this volume-limited sample. This result effectively gives us the distribution of mass for SMBHs residing in spiral galaxies over a lookback time, t{sub L} ≤ 82.1 h{sub 67.77}{sup −1} Myr and contained within a comoving volume, V{sub C} = 3.37 × 10{sup 4} h{sub 67.77}{sup −3} Mpc{sup 3}. We estimate that the density of SMBHs residing in spiral galaxies in the local universe is ρ=5.54{sub −2.73}{sup +6.55} × 10{sup 4} h{sub 67.77}{sup 3} M{sub ☉} Mpc{sup –3}. Thus, our derived cosmological SMBH mass density for spiral galaxies is Ω{sub BH}=4.35{sub −2.15}{sup +5.14} × 10{sup –7} h{sub 67.77}. Assuming that

  15. Magnetizm Localization and Hole Localization in Fermionic Atoms Loaded on Optical Lattice

    NASA Astrophysics Data System (ADS)

    Okumura, Masahiko; Yamada, Susumu; Taniguchi, Nobuhiko; Machida, Masahiko

    2009-03-01

    In order to study an interplay of disorder, correlation, and spin imbalance on antiferromagnetism, we systematically explore the ground state of one-dimensional spin-imbalanced Fermionic atoms loaded on an optical lattice by using the density-matrix renormalization group method [1]. We find that disorders localize the antiferromagnetic spin density wave induced by imbalanced fermions and the increase of the disorder magnitude shrinks the areas of the localized antiferromagnetized regions. Moreover, the antiferromagnetism finally disappears above a large disorder. We also study hole doped cases [2]. Concentrating on the doped-hole density profile, we find in a large U/t regime that the clean system exhibits a simple fluid-like behavior whereas finite disorders create locally Mott regions which expand their area with increasing the disorder strength contrary to the conventional sense. References [1] M. Okumura, S. Yamada, N. Taniguchi, and M. Machida, arXiv:0810:3953. [2] M. Okumura, S. Yamada, N. Taniguchi, and M. Machida, Phys. Rev. Lett. 101 016407 (2008).

  16. Localized AdS5×S5 Black Holes

    NASA Astrophysics Data System (ADS)

    Dias, Óscar J. C.; Santos, Jorge E.; Way, Benson

    2016-10-01

    According to heuristic arguments, global AdS5×S5 black holes are expected to undergo a phase transition in the microcanonical ensemble. At high energies, one expects black holes that respect the symmetries of the S5; at low energies, one expects "localized" black holes that appear pointlike on the S5. According to anti-de Sitter/conformal field theory correspondence, N =4 supersymmetric Yang-Mills (SYM) theory on a 3-sphere should therefore exhibit spontaneous R -symmetry breaking at strong coupling. In this Letter, we numerically construct these localized black holes. We extrapolate the location of this phase transition, and compute the expectation value of the broken scalar operator with lowest conformal dimension. Via the correspondence, these results offer quantitative predictions for N =4 SYM theory.

  17. Local invariants vanishing on stationary horizons: a diagnostic for locating black holes.

    PubMed

    Page, Don N; Shoom, Andrey A

    2015-04-10

    Inspired by the example of Abdelqader and Lake for the Kerr metric, we construct local scalar polynomial curvature invariants that vanish on the horizon of any stationary black hole: the squared norms of the wedge products of n linearly independent gradients of scalar polynomial curvature invariants, where n is the local cohomogeneity of the spacetime.

  18. Local invariants vanishing on stationary horizons: a diagnostic for locating black holes.

    PubMed

    Page, Don N; Shoom, Andrey A

    2015-04-10

    Inspired by the example of Abdelqader and Lake for the Kerr metric, we construct local scalar polynomial curvature invariants that vanish on the horizon of any stationary black hole: the squared norms of the wedge products of n linearly independent gradients of scalar polynomial curvature invariants, where n is the local cohomogeneity of the spacetime. PMID:25910105

  19. The coevolution of galaxies and supermassive black holes: a local perspective.

    PubMed

    Heckman, Timothy M; Kauffmann, Guinevere

    2011-07-01

    One of the most fascinating discoveries in the past decade was that galaxies typically contain a centrally located black hole with a mass that is millions or even billions of times that of the Sun. There is now compelling evidence that we cannot understand how galaxies formed and evolved without understanding the life cycles of these supermassive black holes (and vice versa). We summarize the current understanding of this coevolution of galaxies and supermassive black holes (based largely on observations of the local, present-day universe) and describe prospects for the future.

  20. Local free-fall temperature of modified Schwarzschild black hole in rainbow spacetime

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Wan; Park, Young-Jai

    2016-06-01

    We obtain a (5+1)-dimensional global flat embedding of modified Schwarzschild black hole in rainbow gravity. We show that local free-fall temperature in rainbow gravity, which depends on different energy ω of a test particle, is finite at the event horizon for a freely falling observer, while local temperature is divergent at the event horizon for a fiducial observer. Moreover, these temperatures in rainbow gravity satisfy similar relations to those of the Schwarzschild black hole except the overall factor g(ω), which plays a key role of rainbow functions in this embedding approach.

  1. Horizon News Function and Quasi-Local Energy-Momentum Flux Near Black Hole

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Huei

    2008-09-01

    From the 'quasi-local' definition of horizons, e.g. isolated horizon and dynamical horizon, the consequence quasi-local energy-momentum near horizons can be observed by using the idea of frame alignment. In particular, we find the horizon news function from the asymptotic expansion near horizons and use this to describe the gravitational flux and change of mass of a black hole.

  2. A local characterization for static charged black holes

    NASA Astrophysics Data System (ADS)

    González, Guillermo A.; Vera, Raül

    2011-01-01

    We obtain a purely local characterization that singles out the Majumdar-Papapetrou class, the near-horizon Bertotti-Robinson geometry and the Reissner-Nordström exterior solution, together with its plane and hyperbolic counterparts, among the static electrovacuum spacetimes. These five classes are found to form the whole set of static Einstein-Maxwell fields without sources and conformally flat space of orbits, that is, the conformastat electrovacuum spacetimes. The main part of the proof consists in showing that a functional relationship between the gravitational and electromagnetic potentials must always exist. The classification procedure also provides an improved characterization of Majumdar-Papapetrou, by only requiring a conformally flat space of orbits with a vanishing Ricci scalar of the usual conveniently rescaled 3-metric. A simple global consideration allows us to state that the asymptotically flat subset of the Majumdar-Papapetrou class and the Reissner-Nordström exterior solution are the only asymptotically flat conformastat electrovacuum spacetimes.

  3. Dynamics of localized Kaluza-Klein black holes in a collapsing universe

    NASA Astrophysics Data System (ADS)

    Kastor, David; Sorbo, Lorenzo; Traschen, Jennie

    2012-03-01

    The Clayton Antitrust Act of 1914 prohibits corporate mergers that would result in certain highly undesired end states. We study an exact solution of the Einstein equations describing localized, charged Kaluza-Klein black holes in a collapsing de Sitter universe and seek to demonstrate that a similar effect holds, preventing a potentially catastrophic black hole merger. As the collapse proceeds, it is natural to expect that the black hole undergoes a topological transition, wrapping around the shrinking compact dimension to merge with itself and form a black string. However, the putative uniform charged black string end state is singular and such a transition would violate (a reasonable notion of) cosmic censorship. We present analytic and numerical evidence that strongly suggests the absence of such a transition. Based on this evidence, we expect that the Kaluza-Klein black hole horizon stays localized, despite the increasingly constraining size of the compact dimension. On the other hand, the de Sitter horizon does change between spherical and cylindrical topologies in a simple way.

  4. Effects of local electric surface potential on holes charging process in uncapped germanium nanocrystal

    SciTech Connect

    Marchand, Aude; El Hdiy, Abdelillah

    2015-04-21

    The charging kinetics of holes are investigated in an uncapped Ge nanocrystal by the use of the nano-electron beam induced current technique. The charging process is studied under zero volt or under an appropriate electric field. The investigation is repeated many times on the same nanocrystal and on others in the same sample to attest of the reproducibility of the results. At 0 V, the cycles of charging kinetics are superimposed and are in a steady state, but an instantaneous local and negative surface potential, established in the nanocrystal at the beginning of the kinetics, slows down the holes charging process. Under an external field, the energy band bending accentuation affects the holes charging time constants. As a result, the holes charging cycles weakly affect the electrical performance of the thin oxide as is indicated by the value of the measured local resistivity of 6 × 10{sup 10}–10{sup 11} Ω cm, which is relatively lower than that of the thick thermal oxide.

  5. Finite N and the failure of bulk locality: black holes in AdS/CFT

    NASA Astrophysics Data System (ADS)

    Kabat, Daniel; Lifschytz, Gilad

    2014-09-01

    We consider bulk quantum fields in AdS/CFT in the background of an eternal black hole. We show that for black holes with finite entropy, correlation functions of semiclassical bulk operators close to the horizon deviate from their semiclassical value and are ill-defined inside the horizon. This is due to the large-time behavior of correlators in a unitary CFT, and means the region near and inside the horizon receives corrections. We give a prescription for modifying the definition of a bulk field in a black hole background, such that one can still define operators that mimic the inside of the horizon, but at the price of violating microcausality. For supergravity fields we find that commutators at spacelike separation generically ~ e - S/2. Similar results hold for stable black holes that form in collapse. The general lesson may be that a small amount of non-locality, even over arbitrarily large spacelike distances, is an essential aspect of non-perturbative quantum gravity.

  6. Detailed measurements of local heat transfer coefficient in the entrance to normal and inclined film cooling holes

    SciTech Connect

    Gillespie, D.R.H.; Byerley, A.R.; Ireland, P.T.; Wang, Z.; Jones, T.V.; Kohler, S.T.

    1996-04-01

    The local heat transfer inside the entrance to large-scale models of film cooling holes has been measured using the transient heat transfer technique. The method employs temperature-sensitive liquid crystals to measure the surface temperature of large-scale perspex models. Full distributions of local Nusselt number were calculated based on the cooling passage centerline gas temperature ahead of the cooling hole. The circumferentially averaged Nusselt number was also calculated based on the local mixed bulk driving gas temperature to aid interpretation of the results, and to broaden the potential application of the data. Data are presented for a single film cooling hole inclined at 90 and 150 deg to the coolant duct wall. Both holes exhibited entry length heat transfer levels that were significantly lower than those predicted by entry length data in the presence of crossflow. The reasons for the comparative reduction are discussed in terms of the interpreted flow field.

  7. Particle-hole symmetry, many-body localization, and topological edge modes

    NASA Astrophysics Data System (ADS)

    Vasseur, Romain; Friedman, Aaron J.; Parameswaran, S. A.; Potter, Andrew C.

    We study the excited states of interacting fermions in one dimension with particle-hole symmetric disorder (equivalently, random-bond XXZ chains) using a combination of renormalization group methods and exact diagonalization. Absent interactions, the entire many-body spectrum exhibits infinite-randomness quantum critical behavior with highly degenerate excited states. We show that though interactions are an irrelevant perturbation in the ground state, they drastically affect the structure of excited states: even arbitrarily weak interactions split the degeneracies in favor of thermalization (weak disorder) or spontaneously broken particle-hole symmetry, driving the system into a many-body localized spin glass phase (strong disorder). In both cases, the quantum critical properties of the non-interacting model are destroyed, either by thermal decoherence or spontaneous symmetry breaking. This system then has the interesting and counterintuitive property that edges of the many-body spectrum are less localized than the center of the spectrum. We argue that our results rule out the existence of certain excited state symmetry-protected topological orders. Supported by the Gordon and Betty Moore Foundation's EPiQS Initiative (Grant GBMF4307 (ACP), the Quantum Materials Program at LBNL (RV), NSF Grant DMR-1455366 and UCOP Research Catalyst Award No. CA-15-327861 (SAP).

  8. Particle-hole symmetry, many-body localization, and topological edge modes

    NASA Astrophysics Data System (ADS)

    Vasseur, Romain; Friedman, Aaron J.; Parameswaran, S. A.; Potter, Andrew C.

    2016-04-01

    We study the excited states of interacting fermions in one dimension with particle-hole symmetric disorder (equivalently, random-bond XXZ chains) using a combination of renormalization group methods and exact diagonalization. Absent interactions, the entire many-body spectrum exhibits infinite-randomness quantum critical behavior with highly degenerate excited states. We show that though interactions are an irrelevant perturbation in the ground state, they drastically affect the structure of excited states: Even arbitrarily weak interactions split the degeneracies in favor of thermalization (weak disorder) or spontaneously broken particle-hole symmetry, driving the system into a many-body localized spin glass phase (strong disorder). In both cases, the quantum critical properties of the noninteracting model are destroyed, either by thermal decoherence or spontaneous symmetry breaking. This system then has the interesting and counterintuitive property that edges of the many-body spectrum are less localized than the center of the spectrum. We argue that our results rule out the existence of certain excited state symmetry-protected topological orders.

  9. Effects of hole localization on limiting p-type conductivity in oxide and nitride semiconductors

    SciTech Connect

    Lyons, J. L.; Janotti, A.; Van de Walle, C. G.

    2014-01-07

    We examine how hole localization limits the effectiveness of substitutional acceptors in oxide and nitride semiconductors and explain why p-type doping of these materials has proven so difficult. Using hybrid density functional calculations, we find that anion-site substitutional impurities in AlN, GaN, InN, and ZnO lead to atomic-like states that localize on the impurity atom itself. Substitution with cation-site impurities, on the other hand, triggers the formation of polarons that become trapped on nearest-neighbor anions, generally leading to large ionization energies for these acceptors. Unlike shallow effective-mass acceptors, these two types of deep acceptors couple strongly with the lattice, significantly affecting the optical properties and severely limiting prospects for achieving p-type conductivity in these wide-band-gap materials.

  10. Local Luminous Infrared Galaxies. III. Co-evolution of Black Hole Growth and Star Formation Activity?

    NASA Astrophysics Data System (ADS)

    Alonso-Herrero, Almudena; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang, Yiping; Hernán-Caballero, Antonio; Rigopoulou, Dimitra

    2013-03-01

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 × 107 M ⊙ using [Ne III] 15.56 μm and optical [O III] λ5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear ~1.5 kpc region, as estimated from the nuclear 11.3 μm PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.

  11. LOCAL LUMINOUS INFRARED GALAXIES. III. CO-EVOLUTION OF BLACK HOLE GROWTH AND STAR FORMATION ACTIVITY?

    SciTech Connect

    Alonso-Herrero, Almudena; Hernan-Caballero, Antonio; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang Yiping; Rigopoulou, Dimitra

    2013-03-10

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 Multiplication-Sign 10{sup 7} M{sub Sun} using [Ne III] 15.56 {mu}m and optical [O III] {lambda}5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear {approx}1.5 kpc region, as estimated from the nuclear 11.3 {mu}m PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy.

  12. Sky Localization of Complete Inspiral-Merger-Ringdown Signals for Nonspinning Black Hole Binaries with LISA

    NASA Technical Reports Server (NTRS)

    McWilliams, Sean T.; Lang, Ryan N.; Baker, John G.; Thorpe, James Ira

    2011-01-01

    We investigate the capability of LISA to measure the sky position of equal-mass, nonspinning black hole binaries, including for the first time the entire inspiral-merger-ringdown signal, the effect of the LISA orbits, and the complete three-channel LISA response. For an ensemble of systems near the peak of LISA's sensitivity band, with total rest mass of 2 x l0(exp 6) Stellar Mass at a redshift of z = 1 with random orientations and sky positions, we find median sky localization errors of approximately approx. 3 arcminutes. This is comparable to the field of view of powerful electromagnetic telescopes, such as the James Webb Space Telescope, that could be used to search for electromagnetic signals associated with merging black holes. We investigate the way in which parameter errors decrease with measurement time, focusing specifically on the additional information provided during the merger-ringdown segment of the signal. We find that this information improves all parameter estimates directly, rather than through diminishing correlations with any subset of well-determined parameters.

  13. Surface structure and hole localization in bismuth vanadate: A first principles study

    SciTech Connect

    Kweon, Kyoung E.; Hwang, Gyeong S.

    2013-09-23

    The monoclinic and tetragonal phases of bismuth vanadate (BiVO{sub 4}) have been found to exhibit significantly different photocatalytic activities for water splitting. To assess a possible surface effect on the phase-dependent behavior, we calculate and compare the geometries and electronic structures of the monoclinic and tetragonal BiVO{sub 4} (001) surfaces using hybrid density functional theory. The relaxed atomic configurations of these two surfaces are found to be nearly identical, while an excess hole shows a relatively stronger tendency to localize at the surface than the bulk in both phases. Possible factors for the phase-dependent photocatalytic activity of BiVO{sub 4} are discussed.

  14. Asymptotically locally flat spacetimes and dynamical nonspherically-symmetric black holes in three dimensions

    NASA Astrophysics Data System (ADS)

    Barnich, Glenn; Troessaert, Cédric; Tempo, David; Troncoso, Ricardo

    2016-04-01

    The theory of massive gravity proposed by Bergshoeff, Hohm and Townsend is considered in the special case of the pure irreducibly fourth-order quadratic Lagrangian. It is shown that the asymptotically locally flat black holes of this theory can be consistently deformed to "black flowers" that are no longer spherically symmetric. Moreover, we construct radiating spacetimes settling down to these black flowers in the far future. The generic case can be shown to fit within a relaxed set of asymptotic conditions as compared to the ones of general relativity at null infinity, while the asymptotic symmetries remain the same. Conserved charges as surface integrals at null infinity are constructed following a covariant approach, and their algebra represents BMS3 , but without central extensions. For solutions possessing an event horizon, we derive the first law of thermodynamics from these surface integrals.

  15. Effect of black holes in local dwarf spheroidal galaxies on gamma-ray constraints on dark matter annihilation

    NASA Astrophysics Data System (ADS)

    Gonzalez-Morales, Alma X.; Profumo, Stefano; Queiroz, Farinaldo S.

    2014-11-01

    Recent discoveries of optical signatures of black holes in dwarf galaxies indicates that low-mass galaxies can indeed host intermediate massive black holes. This motivates the assessment of the resulting effect on the host dark matter density profile, and the consequences for the constraints on the plane of the dark matter annihilation cross section versus mass, stemming from the nonobservation of gamma rays from local dwarf spheroidals with the Fermi Large Area Telescope. We compute the density profile using three different prescriptions for the black hole mass associated with a given spheroidal galaxy, and taking into account the cutoff to the density from dark matter pair-annihilation. We find that the limits on the dark matter annihilation rate from observations of individual dwarfs are enhanced by factors of a few up to 1 06 , depending on the specific galaxy, on the black hole mass prescription, and on the dark matter particle mass. We estimate limits from combined observations of a sample of 15 dwarfs, for a variety of assumptions on the dwarf black hole mass and on the dark matter density profile prior to adiabatic contraction. We find that if black holes are indeed present in local dwarf spheroidals, then, independent of assumptions, (i) the dark matter interpretation of the Galactic center gamma-ray excess would be conclusively ruled out, (ii) wino dark matter would be excluded up to masses of about 3 TeV, and (iii) vanilla thermal relic weakly interacting massive particles must be heavier than 100 GeV.

  16. Observational Signatures of High-Redshift Quasars and Local Relics of Black Hole Seeds

    NASA Astrophysics Data System (ADS)

    Reines, Amy E.; Comastri, Andrea

    2016-10-01

    Observational constraints on the birth and early evolution of massive black holes come from two extreme regimes. At high redshift, quasars signal the rapid growth of billion-solar-mass black holes and indicate that these objects began remarkably heavy and/or accreted mass at rates above the Eddington limit. At low redshift, the smallest nuclear black holes known are found in dwarf galaxies and provide the most concrete limits on the mass of black hole seeds. Here, we review current observational work in these fields that together are critical for our understanding of the origin of massive black holes in the Universe.

  17. Focused Impedance Method (FIM) and Pigeon Hole Imaging (PHI) for localized measurements - a review

    NASA Astrophysics Data System (ADS)

    Siddique-e Rabbani, K.

    2010-04-01

    This paper summarises up to date development in Focused Impedance Method (FIM) initiated by us. It basically involves taking the sum of two orthogonal tetra-polar impedance measurements around a common central region, giving a localized enhanced sensitivity. Although the basic idea requires 8 electrodes, versions with 6- and 4-electrodes were subsequently conceived and developed. The focusing effect has been verified in 2D and 3D phantoms and through numerical analysis. Dynamic stomach emptying, and ventilation of localized lung regions have been studied successfully suggesting further applications in monitoring of gastric acid secretion, artificial respiration, bladder emptying, etc. Multi-frequency FIM may help identify some diseases and disorders including certain cancers. FIM, being much simpler and having less number of electrodes, appears to have the potential to replace EIT for applications involving large and shallow organs. An enhancement of 6-electrode FIM led to Pigeon Hole Imaging (PHI) in a square matrix through backprojection in two orthogonal directions, good for localising of one or two well separated objects.

  18. An AB Initio Study of SbH_2 and BiH_2: the Renner Effect, Spin-Orbit Coupling, Local Mode Vibrations and Rovibronic Energy Level Clustering in SbH_2

    NASA Astrophysics Data System (ADS)

    Ostojic, Bojana; Schwerdtfeger, Peter; Bunker, Phil; Jensen, Per

    2016-06-01

    We present the results of ab initio calculations for the lower electronic states of the Group 15 (pnictogen) dihydrides, SbH_2 and BiH_2. For each of these molecules the two lowest electronic states become degenerate at linearity and are therefore subject to the Renner effect. Spin-orbit coupling is also strong in these two heavy-element containing molecules. For the lowest two electronic states of SbH_2, we construct the three dimensional potential energy surfaces and corresponding dipole moment and transition moment surfaces by multi-reference configuration interaction techniques. Including both the Renner effect and spin-orbit coupling, we calculate term values and simulate the rovibrational and rovibronic spectra of SbH_2. Excellent agreement is obtained with the results of matrix isolation infrared spectroscopic studies and with gas phase electronic spectroscopic studies in absorption [1,2]. For the heavier dihydride BiH_2 we calculate bending potential curves and the spin-orbit coupling constant for comparison. For SbH_2 we further study the local mode vibrational behavior and the formation of rovibronic energy level clusters in high angular momentum states. [1] X. Wang, P. F. Souter and L. Andrews, J. Phys. Chem. A 107, 4244-4249 (2003) [2] N. Basco and K. K. Lee, Spectroscopy Letters 1, 13-15 (1968)

  19. Evidence for Black Hole Growth in Local Analogs to Lyman Break Galaxies

    NASA Technical Reports Server (NTRS)

    Jia, Jianjun; Ptak, Andrew; Heckman, Timothy M.; Overzier, Roderik A.; Hornschemeier, Ann; LaMassa, Stephanie M.

    2011-01-01

    We have used XMM-Newton to observe six Lyman break analogs (LBAs): members of the rare population of local galaxies that have properties that are very similar to distant Lyman break galaxies. Our six targets were specifically selected because they have optical emission-line properties that are intermediate between starbursts and Type 2 (obscured) active galactic nuclei (AGNs). Our new X-ray data provide an important diagnostic of the presence of an AGN. We find X-ray luminosities of order 10(sup 42) erg per second and ratios of X-ray to far-IR lummositles that are higher than values in pure starburst galaxies by factors ranging from approximately 3 to 30. This strongly suggests the presence of an AGN in at least some of the galaxies. The ratios of the luminosities of the hard (2-10 keV) X-ray to [O III] emission line are low by about an order of magnitude compared with Type 1 AGN, but are consistent with the broad range seen in Type 2 AGN. Either the AGN hard X-rays are significantly obscured or the [O III] emission is dominated by the starburst. We searched for an iron emission line at approximately 6.4 ke V, which is a key feature of obscured AGNs, but only detected emission at the approximately 2sigma level. Finally, we find that the ratios of the mid-infrared (24 micrometer) continuum to [O III]lambda 5007 luminosities in these LBAs are higher than the values for Type 2 AGN by an average of 0.8 dex. Combining all these clues, we conclude that an AGN is likely to be present, but that the bolometric luminosity is produced primarily by an intense starburst. If these black holes are radiating at the Eddington limit, their masses would lie in the range of 10(sup 5) - 10(sup 6) solar mass. These objects may offer ideal local laboratories to investigate the processes by which black holes grew in the early universe.

  20. Holes localized in nanostructures in an external magnetic field: g-factor and mixing of states

    SciTech Connect

    Semina, M. A.; Suris, R. A.

    2015-06-15

    The energy spectrum and wave functions of holes in the valence band in semiconductor nanosystems, including quantum wells, quantum wires, and quantum dots, in an external magnetic field are theoretically investigated. The dependence of Zeeman splitting of the hole ground state upon variation in the size-quantization parameters with regard to the complex structure of the valence band and magnetic field-induced mixing of hole states is traced. Analytical formulas for describing the Zeeman effect in the valence band in the limiting cases of a quantum disk, spherically symmetric quantum dot, and quantum wire are presented. It is demonstrated that the g-factor of a hole is extremely sensitive to the hole-state composition (heavy or light hole) and, consequently, to the geometry of the size-quantization potential.

  1. Opening Holes in the Blanket of Inhibition: Localized Lateral Disinhibition by VIP Interneurons

    PubMed Central

    Jackson, Jesse; Ayzenshtat, Inbal; Hamzehei Sichani, Azadeh; Manoocheri, Kasra; Kim, Samuel; Yuste, Rafael

    2016-01-01

    Inhibitory interneurons in the neocortex often connect in a promiscuous and extensive fashion, extending a “blanket of inhibition” on the circuit. This raises the problem of how can excitatory activity propagate in the midst of this widespread inhibition. One solution to this problem could be the vasoactive intestinal peptide (VIP) interneurons, which disinhibit other interneurons. To explore how VIP interneurons affect the local circuits, we use two-photon optogenetics to activate them individually in mouse visual cortex in vivo while measuring their output with two-photon calcium imaging. We find that VIP interneurons have narrow axons and inhibit nearby somatostatin interneurons, which themselves inhibit pyramidal cells. Moreover, via this lateral disinhibition, VIP cells in vivo make local and transient “holes” in the inhibitory blanket extended by SOM cells. VIP interneurons, themselves regulated by neuromodulators, may therefore enable selective patterns of activity to propagate through the cortex, by generating a “spotlight of attention”. SIGNIFICANCE STATEMENT Most inhibitory interneurons have axons restricted to a nearby area and target excitatory neighbors indiscriminately, raising the issue of how neuronal activity can propagate through cortical circuits. Vasoactive intestinal peptide-expressing interneurons (VIPs) disinhibit cortical pyramidal cells through inhibition of other inhibitory interneurons, and they have very focused, “narrow” axons. By optogenetically activating single VIPs in live mice while recording the activity of nearby neurons, we find that VIPs break open a hole in blanket inhibition with an effective range of ∼120 μm in lateral cortical space where excitatory activity can propagate. PMID:27013676

  2. Automated drawing system of quantum energy levels

    NASA Astrophysics Data System (ADS)

    Stampoultzis, M.; Sinatkas, J.; Tsakstara, V.; Kosmas, T. S.

    2014-03-01

    The purpose of this work is to derive an automated system that provides advantageous drawings of energy spectra for quantum systems (nuclei, atoms, molecules, etc.) required in various physical sciences. The automation involves the development of appropriate computational code and graphical imaging system based on raw data insertion, theoretical calculations and experimental or bibliographic data insertion. The system determines the appropriate scale to depict graphically with the best possible way in the available space. The presently developed code operates locally and the results are displayed on the screen and can be exported to a PostScript file. We note its main features to arrange and visualize in the available space the energy levels with their identity, taking care the existence in the final diagram the least auxiliary deviations. Future improvements can be the use of Java and the availability on the Internet. The work involves the automated plotting of energy levels in molecules, atoms, nuclei and other types of quantized energy spectra. The automation involves the development of an appropriate computational code and graphical imaging system.

  3. Communication: Hole localization in Al-doped quartz SiO{sub 2} within ab initio hybrid-functional DFT

    SciTech Connect

    Gerosa, Matteo; Bottani, Carlo Enrico

    2015-09-21

    We investigate the long-standing problem of hole localization at the Al impurity in quartz SiO{sub 2}, using a relatively recent DFT hybrid-functional method in which the exchange fraction is obtained ab initio, based on an analogy with the static many-body COHSEX approximation to the electron self-energy. As the amount of the admixed exact exchange in hybrid functionals has been shown to be determinant for properly capturing the hole localization, this problem constitutes a prototypical benchmark for the accuracy of the method, allowing one to assess to what extent self-interaction effects are avoided. We obtain good results in terms of description of the charge localization and structural distortion around the Al center, improving with respect to the more popular B3LYP hybrid-functional approach. We also discuss the accuracy of computed hyperfine parameters, by comparison with previous calculations based on other self-interaction-free methods, as well as experimental values. We discuss and rationalize the limitations of our approach in computing defect-related excitation energies in low-dielectric-constant insulators.

  4. Ultrasonic inspection of multiple-rivet-hole lap joint cracks using global analysis with local finite element approach

    NASA Astrophysics Data System (ADS)

    Bhuiyan, Yeasin; Shen, Yanfeng; Giurgiutiu, Victor

    2016-04-01

    Ultrasonic inspection of multiple-rivet-hole lap joint cracks has been introduced using combined analytical and finite element approach (CAFA). Finite element analyses have been performed on local damage area in spite of the whole large structure and transfer function based analytical model is used to analyze the full structure. "Scattered cube" of complex valued wave damage interaction coefficient (WDIC) that involves scattering and mode conversion of Lamb waves around the damage is used as coupling between analytical and FEM simulation. WDIC is captured for multiple angles of incident Lamb mode (S0 and A0) over the frequency domain to analyze the cracks of multiple-rivet-hole lap joint. By analyzing the scattered cube of WDICs over the frequency domain and azimuthal angles the optimum parameters can be determined for each angle of incidence and the most sensitive signals are obtained using WaveformRevealer2D (WFR2D). These sensitive signals confirm the detection of the butterfly cracks in rivet holes through the installment of the transmitting and sensing PWASs in the proper locations and selecting the right frequency of excitation.

  5. X-RAY CONSTRAINTS ON THE LOCAL SUPERMASSIVE BLACK HOLE OCCUPATION FRACTION

    SciTech Connect

    Miller, Brendan P.; Gallo, Elena; Baldassare, Vivienne; Greene, Jenny E.; Kelly, Brandon C.; Treu, Tommaso; Woo, Jong-Hak

    2015-01-20

    Distinct seed formation mechanisms are imprinted upon the fraction of dwarf galaxies currently containing a central supermassive black hole. Seeding by Population III remnants is expected to produce a higher occupation fraction than is generated with direct gas collapse precursors. Chandra observations of nearby early-type galaxies can directly detect even low-level supermassive black hole activity, and the active fraction immediately provides a firm lower limit to the occupation fraction. Here, we use the volume-limited AMUSE surveys of ∼200 optically selected early-type galaxies to characterize simultaneously, for the first time, the occupation fraction and the scaling of L {sub X} with M {sub star}, accounting for intrinsic scatter, measurement uncertainties, and X-ray limits. For early-type galaxies with M {sub star} < 10{sup 10} M {sub ☉}, we obtain a lower limit to the occupation fraction of >20% (at 95% confidence), but full occupation cannot be excluded. The preferred dependence of log L {sub X} upon log M {sub star} has a slope of ∼0.7-0.8, consistent with the ''downsizing'' trend previously identified from the AMUSE data set, and a uniform Eddington efficiency is disfavored at ∼2σ. We provide guidelines for the future precision with which these parameters may be refined with larger or more sensitive samples.

  6. Proof of the local mass-angular momenta inequality for U{(1)}^{2} invariant black holes

    NASA Astrophysics Data System (ADS)

    Alaee, Aghil; Kunduri, Hari K.

    2015-08-01

    We consider initial data for extreme vacuum asymptotically flat black holes with {{R}}× U{(1)}2 symmetry. Such geometries are critical points of a mass functional defined for a wide class of asymptotically flat, ‘(t-{φ }i)’ symmetric maximal initial data for the vacuum Einstein equations. We prove that the above extreme geometries are local minima of mass among nearby initial data (with the same interval structure) with fixed angular momenta. Thus the ADM mass of nearby data m≥slant f({J}1,{J}2) for some function f depending on the interval structure. The proof requires that the initial data of the critical points satisfy certain conditions that are satisfied by the extreme Myers-Perry and extreme black ring data.

  7. Individual electron and hole localization in submonolayer InN quantum sheets embedded in GaN

    NASA Astrophysics Data System (ADS)

    Feix, F.; Flissikowski, T.; Chèze, C.; Calarco, R.; Grahn, H. T.; Brandt, O.

    2016-07-01

    We investigate sub-monolayer InN quantum sheets embedded in GaN(0001) by temperature-dependent photoluminescence spectroscopy under both continuous-wave and pulsed excitation. Both the peak energy and the linewidth of the emission band associated with the quantum sheets exhibit an anomalous dependence on temperature indicative of carrier localization. Photoluminescence transients reveal a power law decay at low temperatures reflecting that the recombining electrons and holes occupy spatially separate, individual potential minima reminiscent of conventional (In,Ga)N(0001) quantum wells exhibiting the characteristic disorder of a random alloy. At elevated temperatures, carrier delocalization sets in and is accompanied by a thermally activated quenching of the emission. We ascribe the strong nonradiative recombination to extended states in the GaN barriers and confirm our assumption by a simple rate-equation model.

  8. RELATIONS BETWEEN CENTRAL BLACK HOLE MASS AND TOTAL GALAXY STELLAR MASS IN THE LOCAL UNIVERSE

    SciTech Connect

    Reines, Amy E.; Volonteri, Marta

    2015-11-10

    Scaling relations between central black hole (BH) mass and host galaxy properties are of fundamental importance to studies of BH and galaxy evolution throughout cosmic time. Here we investigate the relationship between BH mass and host galaxy total stellar mass using a sample of 262 broad-line active galactic nuclei (AGNs) in the nearby universe (z < 0.055), as well as 79 galaxies with dynamical BH masses. The vast majority of our AGN sample is constructed using Sloan Digital Sky Survey spectroscopy and searching for Seyfert-like narrow-line ratios and broad Hα emission. BH masses are estimated using standard virial techniques. We also include a small number of dwarf galaxies with total stellar masses M{sub stellar} ≲ 10{sup 9.5} M{sub ⊙} and a subsample of the reverberation-mapped AGNs. Total stellar masses of all 341 galaxies are calculated in the most consistent manner feasible using color-dependent mass-to-light ratios. We find a clear correlation between BH mass and total stellar mass for the AGN host galaxies, with M{sub BH} ∝ M{sub stellar}, similar to that of early-type galaxies with dynamically detected BHs. However, the relation defined by the AGNs has a normalization that is lower by more than an order of magnitude, with a BH-to-total stellar mass fraction of M{sub BH}/M{sub stellar} ∼ 0.025% across the stellar mass range 10{sup 8} ≤ M{sub stellar}/M{sub ⊙} ≤ 10{sup 12}. This result has significant implications for studies at high redshift and cosmological simulations in which stellar bulges cannot be resolved.

  9. Estimation Using an Enhancement Factor on Non Local Thermodynamic Equilibrium Behavior of High-lying Energy Levels of Neutral Atom in Argon Radio-Frequency Inductively-Coupled Plasma.

    PubMed

    Wagatsuma, Kazuaki; Satoh, Kozue

    2016-01-01

    This paper describes a plasma-diagnostic method using an enhancement factor on the Boltzmann distribution among emission lines of iron atom in an argon radio-frequency inductively-coupled plasma (ICP). It indicated that Boltzmann plots of the atomic lines having lower excitation energies (3.4 to 4.8 eV) were well fitted on a straight line while those having more than 5.5 eV deviated upwards from a linear relationship. This observation could be explained by the fact that ICP is not in a complete thermodynamic equilibrium between direct excitation to energy levels of iron atom, ionization of iron atom, and radiative decay processes to the ground state. Especially, the recombination of iron ion with captured electron should accompany cascade de-excitations between closely-spaced excited levels just below the ionization limit, the rates of which become slower as a whole; as a result, these high-lying levels might be more populated than the low-lying levels as if a different LTE condition coexists on the high energy side. This overpopulation could be quantitatively estimated using an enhancement factor (EF), which was a ratio of the observed intensity to the expected value extrapolated from the normal distribution on the low energy side. The EFs were generally small (less than 3); therefore, the cascade de-excitation process would slightly contribute to the population of these excited levels. It could be considered from variations of the EF that the overpopulation proceeded to a larger extent at lower radio-frequency forward powers, at higher flow rates of the carrier gas, or at higher observation heights. The reason for this is that the kinetic energy of energetic particles, such as electrons, becomes reduced under all of these plasma conditions, thus enabling the high-lying levels to be more populated by cascade de-excitation processes from iron ion rather than by collisional excitation processes with the energetic particles. A similar Boltzmann analysis using the EF

  10. Estimation Using an Enhancement Factor on Non Local Thermodynamic Equilibrium Behavior of High-lying Energy Levels of Neutral Atom in Argon Radio-Frequency Inductively-Coupled Plasma.

    PubMed

    Wagatsuma, Kazuaki; Satoh, Kozue

    2016-01-01

    This paper describes a plasma-diagnostic method using an enhancement factor on the Boltzmann distribution among emission lines of iron atom in an argon radio-frequency inductively-coupled plasma (ICP). It indicated that Boltzmann plots of the atomic lines having lower excitation energies (3.4 to 4.8 eV) were well fitted on a straight line while those having more than 5.5 eV deviated upwards from a linear relationship. This observation could be explained by the fact that ICP is not in a complete thermodynamic equilibrium between direct excitation to energy levels of iron atom, ionization of iron atom, and radiative decay processes to the ground state. Especially, the recombination of iron ion with captured electron should accompany cascade de-excitations between closely-spaced excited levels just below the ionization limit, the rates of which become slower as a whole; as a result, these high-lying levels might be more populated than the low-lying levels as if a different LTE condition coexists on the high energy side. This overpopulation could be quantitatively estimated using an enhancement factor (EF), which was a ratio of the observed intensity to the expected value extrapolated from the normal distribution on the low energy side. The EFs were generally small (less than 3); therefore, the cascade de-excitation process would slightly contribute to the population of these excited levels. It could be considered from variations of the EF that the overpopulation proceeded to a larger extent at lower radio-frequency forward powers, at higher flow rates of the carrier gas, or at higher observation heights. The reason for this is that the kinetic energy of energetic particles, such as electrons, becomes reduced under all of these plasma conditions, thus enabling the high-lying levels to be more populated by cascade de-excitation processes from iron ion rather than by collisional excitation processes with the energetic particles. A similar Boltzmann analysis using the EF

  11. Hole localization or delocalization an optical, Raman, and redox study of lanthanide porphyrin-phthalocyanine sandwich-type heterocomplexes

    SciTech Connect

    Tran-Thi, T.H.; Mattioli, T.A. ); Chabach, D.; De Cian, A.; Weiss, R. )

    1994-08-25

    A systematic electrochemical, redox, optical absorption, and resonance Raman spectroscopic study of 22 gadolinium and cerium double- and triple-decker tetraphenylporphyrin-phthalocyanine (TPP-Pc) complexes is reported. The work is aimed at elucidating the extent of the localization or delocalization among the chromophore ligands in the mixed complexes, where there exists a charge imbalance between the metal centers and the dianion Pc/TPP ligands, as well as in different oxidation states for these types of complexes. For mixed double- and triple-decker complexes, [vert bar]Pc(M)TPP[vert bar] and [vert bar]TPP(M)TPP[vert bar] (where M = Gd[sup III], Ce[sup IV]), in which the metal cannot be oxidized, it appears that the ligand preferentially oxidized is the Pc moiety. This perfentially localized hole in the phthalocyanine results in new near-infrared transitions which show maxima around 1200-1300 nm for the double-decker complexes and shifts to 1800-2300 nm for the triple-decker derivatives. In this case, the removal of an electron from a complex redox orbital which is rich in Pc character is easily identified by the accompanying changes in the optical absorption characteristic of a Pc[sup [sm bullet][minus

  12. Energy Levels of Hydrogen and Deuterium

    National Institute of Standards and Technology Data Gateway

    SRD 142 Energy Levels of Hydrogen and Deuterium (Web, free access)   This database provides theoretical values of energy levels of hydrogen and deuterium for principle quantum numbers n = 1 to 200 and all allowed orbital angular momenta l and total angular momenta j. The values are based on current knowledge of the revelant theoretical contributions including relativistic, quantum electrodynamic, recoil, and nuclear size effects.

  13. A Local Baseline of the Black Hole Mass Scaling Relations for Active Galaxies. I. Methodology and Results of Pilot Study

    NASA Astrophysics Data System (ADS)

    Bennert, Vardha Nicola; Auger, Matthew W.; Treu, Tommaso; Woo, Jong-Hak; Malkan, Matthew A.

    2011-01-01

    We present high-quality Keck/LRIS long-slit spectroscopy of a pilot sample of 25 local active galaxies selected from the SDSS (0.02 <=z <= 0.1; M BH>107 M sun) to study the relations between black hole mass (M BH) and host-galaxy properties. We determine stellar kinematics of the host galaxy, deriving stellar-velocity dispersion profiles and rotation curves from three spectral regions (including CaH&K, MgIb triplet, and Ca II triplet). In addition, we perform surface photometry on SDSS images, using a newly developed code for joint multi-band analysis. BH masses are estimated from the width of the Hβ emission line and the host-galaxy free 5100 Å active galactic nucleus (AGN) luminosity. Combining results from spectroscopy and imaging allows us to study four M BH scaling relations: M BH-σ, M BH-L sph, M BH-M sph,sstarf, and M BH-M sph,dyn. We find the following results. First, stellar-velocity dispersions determined from aperture spectra (e.g., SDSS fiber spectra or unresolved data from distant galaxies) can be biased, depending on aperture size, AGN contamination, and host-galaxy morphology. However, such a bias cannot explain the offset seen in the M BH-σ relation at higher redshifts. Second, while the CaT region is the cleanest to determine stellar-velocity dispersions, both the MgIb region, corrected for Fe II emission, and the CaHK region, although often swamped by the AGN power-law continuum and emission lines, can give results accurate to within a few percent. Third, the M BH scaling relations of our pilot sample agree in slope and scatter with those of other local active and inactive galaxies. In the next papers of the series we will quantify the scaling relations, exploiting the full sample of ~100 objects.

  14. Energy levels for F-16 (Fluorine-16)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of Subvolume C `Tables of Excitations of Proton- and Neutron-rich Unstable Nuclei' of Volume 19 `Nuclear States from Charged Particle Reactions' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides energy levels for atomic nuclei of the isotope F-16 (fluorine, atomic number Z = 9, mass number A = 16).

  15. Energy level control: toward an efficient hot electron transport

    NASA Astrophysics Data System (ADS)

    Jin, Xiao; Li, Qinghua; Li, Yue; Chen, Zihan; Wei, Tai-Huei; He, Xingdao; Sun, Weifu

    2014-08-01

    Highly efficient hot electron transport represents one of the most important properties required for applications in photovoltaic devices. Whereas the fabrication of efficient hot electron capture and lost-cost devices remains a technological challenge, regulating the energy level of acceptor-donor system through the incorporation of foreign ions using the solution-processed technique is one of the most promising strategies to overcome this obstacle. Here we present a versatile acceptor-donor system by incorporating MoO3:Eu nanophosphors, which reduces both the `excess' energy offset between the conduction band of acceptor and the lowest unoccupied molecular orbital of donor, and that between the valence band and highest occupied molecular orbital. Strikingly, the hot electron transfer time has been shortened. This work demonstrates that suitable energy level alignment can be tuned to gain the higher hot electron/hole transport efficiency in a simple approach without the need for complicated architectures. This work builds up the foundation of engineering building blocks for third-generation solar cells.

  16. Energy level control: toward an efficient hot electron transport.

    PubMed

    Jin, Xiao; Li, Qinghua; Li, Yue; Chen, Zihan; Wei, Tai-Huei; He, Xingdao; Sun, Weifu

    2014-08-07

    Highly efficient hot electron transport represents one of the most important properties required for applications in photovoltaic devices. Whereas the fabrication of efficient hot electron capture and lost-cost devices remains a technological challenge, regulating the energy level of acceptor-donor system through the incorporation of foreign ions using the solution-processed technique is one of the most promising strategies to overcome this obstacle. Here we present a versatile acceptor-donor system by incorporating MoO3:Eu nanophosphors, which reduces both the 'excess' energy offset between the conduction band of acceptor and the lowest unoccupied molecular orbital of donor, and that between the valence band and highest occupied molecular orbital. Strikingly, the hot electron transfer time has been shortened. This work demonstrates that suitable energy level alignment can be tuned to gain the higher hot electron/hole transport efficiency in a simple approach without the need for complicated architectures. This work builds up the foundation of engineering building blocks for third-generation solar cells.

  17. A Local Baseline of the Black Hole Mass Scaling Relations for Active Galaxies. III.The MBH– Relation

    NASA Astrophysics Data System (ADS)

    Bennert, Vardha N.; Treu, Tommaso; Auger, Matthew W.; Cosens, Maren; Park, Daeseong; Rosen, Rebecca; Harris, Chelsea E.; Malkan, Matthew A.; Woo, Jong-Hak

    2015-08-01

    We create a baseline of the black hole (BH) mass ({M}{BH})—stellar-velocity dispersion (σ) relation for active galaxies, using a sample of 66 local (0.02\\lt z\\lt 0.09) Seyfert-1 galaxies, selected from the Sloan Digital Sky Survey (SDSS). Analysis of SDSS images yields AGN luminosities free of host-galaxy contamination, and morphological classification. 51/66 galaxies have spiral morphology. Out of these, 28 bulges have Sérsic index n\\lt 2 and are considered candidate pseudo-bulges, with eight being definite pseudo-bulges based on multiple classification criteria met. Only 4/66 galaxies show signs of interaction/merging. High signal-to-noise ratio Keck spectra provide the width of the broad Hβ emission line free of Fe ii emission and stellar absorption. AGN luminosity and Hβ line widths are used to estimate {M}{BH}. The Keck-based spatially resolved kinematics is used to determine stellar-velocity dispersion within the spheroid effective radius ({σ }{spat,{reff}}). We find that σ can vary on average by up to 40% across definitions commonly used in the literature, emphasizing the importance of using self-consistent definitions in comparisons and evolutionary studies. The {M}{BH}–σ relation for our Seyfert-1 galaxy sample has the same intercept and scatter as that of reverberation-mapped AGNs as well as that of quiescent galaxies, consistent with the hypothesis that our single epoch {M}{BH} estimator and sample selection function do not introduce significant biases. Barred galaxies, merging galaxies, and those hosting pseudo-bulges do not represent outliers in the {M}{BH}–σ relation. This is in contrast with previous work, although no firm conclusion can be drawn on this matter due to the small sample size and limited resolution of the SDSS images.

  18. A LOCAL BASELINE OF THE BLACK HOLE MASS SCALING RELATIONS FOR ACTIVE GALAXIES. I. METHODOLOGY AND RESULTS OF PILOT STUDY

    SciTech Connect

    Bennert, Vardha Nicola; Auger, Matthew W.; Treu, Tommaso; Woo, Jong-Hak; Malkan, Matthew A. E-mail: mauger@physics.ucsb.edu E-mail: woo@astro.snu.ac.kr

    2011-01-10

    We present high-quality Keck/LRIS long-slit spectroscopy of a pilot sample of 25 local active galaxies selected from the SDSS (0.02 {<=}z {<=} 0.1; M{sub BH}>10{sup 7} M{sub sun}) to study the relations between black hole mass (M{sub BH}) and host-galaxy properties. We determine stellar kinematics of the host galaxy, deriving stellar-velocity dispersion profiles and rotation curves from three spectral regions (including CaH and K, MgIb triplet, and Ca II triplet). In addition, we perform surface photometry on SDSS images, using a newly developed code for joint multi-band analysis. BH masses are estimated from the width of the H{beta} emission line and the host-galaxy free 5100 A active galactic nucleus (AGN) luminosity. Combining results from spectroscopy and imaging allows us to study four M{sub BH} scaling relations: M{sub BH}-{sigma}, M{sub BH}-L{sub sph}, M{sub BH}-M{sub sph,*}, and M{sub BH}-M{sub sph,dyn}. We find the following results. First, stellar-velocity dispersions determined from aperture spectra (e.g., SDSS fiber spectra or unresolved data from distant galaxies) can be biased, depending on aperture size, AGN contamination, and host-galaxy morphology. However, such a bias cannot explain the offset seen in the M{sub BH}-{sigma} relation at higher redshifts. Second, while the CaT region is the cleanest to determine stellar-velocity dispersions, both the MgIb region, corrected for Fe II emission, and the CaHK region, although often swamped by the AGN power-law continuum and emission lines, can give results accurate to within a few percent. Third, the M{sub BH} scaling relations of our pilot sample agree in slope and scatter with those of other local active and inactive galaxies. In the next papers of the series we will quantify the scaling relations, exploiting the full sample of {approx}100 objects.

  19. A Firmly Localized Hole Center in the Mineral Brazilianite NaAl3(PO4)2(OH)4

    NASA Astrophysics Data System (ADS)

    Requardt, A.; Hill, F.; Lehmann, G.

    1982-03-01

    A hole center on an oxygen adjacent to one aluminum and one phosphorous was detected and analyzed in natural and X-ray irradiated brazilianite. The slightly anisotropic 27 Al shfs splitting is larger than in many other hole centers in which the Al is a lower valency impurity ion with only a coordinative bond to an oxygen lone pair. The hole is trapped at an oxygen with particularly long bond distances to one P and two Al. Thus one structural Al must be substituted by a presumably divalent cation of yet unknown nature. No optical absorption is associated with this center, therefore the large distortion of the coordination polyhedra must be responsible for absence of a light-induced hole transfer between different oxygen ions. Comparison with other systems suggests that the energy differences for other configurations of the hole center are also too high to allow thermal hopping of the hole at or below room temperature. Possible mechanisms for formation and destruction of this center are deduced from experimental results.

  20. Defect energy levels from current transient recording

    NASA Astrophysics Data System (ADS)

    Momayezi, Michael

    1991-07-01

    Silicon detectors are widely used in high energy physics in vertexing and calorimetry applications. The radiative environment will introduce defects with energy levels in the bandgap into the crystals. At the high levels of radiation present at proton accelerators the defect concentration will easily approach or exceed the doping concentration of the usual high ohmic material. DLTS, the most common technique for defect characterization is known to fail under these conditions. To study heavy radiation damage in silicon detectors a new method has been developed. Using a DLTS-like pulser setup, the current transient from trap emptying is recorded on a fast digital scope being read out by a microcomputer. This is repeatedly done during a temperature scan. The time integral of the current transient equals the number of traps present and the activation enthalpy is found from the temperature dependence of the emission life time. If there is more than one energy level present the individual components may be extracted by a fitting procedure from the then multiexponential current transient. The sensitivity reached so far is, noise and systematics considered, ˜10 9 traps. Lifetimes between 5 μs and 5 ms are covered.

  1. Energy-level alignment at organic heterointerfaces

    PubMed Central

    Oehzelt, Martin; Akaike, Kouki; Koch, Norbert; Heimel, Georg

    2015-01-01

    Today’s champion organic (opto-)electronic devices comprise an ever-increasing number of different organic-semiconductor layers. The functionality of these complex heterostructures largely derives from the relative alignment of the frontier molecular-orbital energies in each layer with respect to those in all others. Despite the technological relevance of the energy-level alignment at organic heterointerfaces, and despite continued scientific interest, a reliable model that can quantitatively predict the full range of phenomena observed at such interfaces is notably absent. We identify the limitations of previous attempts to formulate such a model and highlight inconsistencies in the interpretation of the experimental data they were based on. We then develop a theoretical framework, which we demonstrate to accurately reproduce experiment. Applying this theory, a comprehensive overview of all possible energy-level alignment scenarios that can be encountered at organic heterojunctions is finally given. These results will help focus future efforts on developing functional organic interfaces for superior device performance. PMID:26702447

  2. Energy levels of double triangular graphene quantum dots

    SciTech Connect

    Liang, F. X.; Jiang, Z. T. Zhang, H. Y.; Li, S.; Lv, Z. T.

    2014-09-28

    We investigate theoretically the energy levels of the coupled double triangular graphene quantum dots (GQDs) based on the tight-binding Hamiltonian model. The double GQDs including the ZZ-type, ZA-type, and AA-type GQDs with the two GQDs having the zigzag or armchair boundaries can be coupled together via different interdot connections, such as the direct coupling, the chains of benzene rings, and those of carbon atoms. It is shown that the energy spectrum of the coupled double GQDs is the amalgamation of those spectra of the corresponding two isolated GQDs with the modification triggered by the interdot connections. The interdot connection is inclined to lift up the degeneracies of the energy levels in different degree, and as the connection changes from the direct coupling to the long chains, the removal of energy degeneracies is suppressed in ZZ-type and AA-type double GQDs, which indicates that the two coupled GQDs are inclined to become decoupled. Then we consider the influences on the spectra of the coupled double GQDs induced by the electric fields applied on the GQDs or the connection, which manifests as the global spectrum redistribution or the local energy level shift. Finally, we study the symmetrical and asymmetrical energy spectra of the double GQDs caused by the substrates supporting the two GQDs, clearly demonstrating how the substrates affect the double GQDs' spectrum. This research elucidates the energy spectra of the coupled double GQDs, as well as the mechanics of manipulating them by the electric field and the substrates, which would be a significant reference for designing GQD-based devices.

  3. Charge-compensation in 3d-transition-metal-oxide intercalation cathodes through the generation of localized electron holes on oxygen.

    PubMed

    Luo, Kun; Roberts, Matthew R; Hao, Rong; Guerrini, Niccoló; Pickup, David M; Liu, Yi-Sheng; Edström, Kristina; Guo, Jinghua; Chadwick, Alan V; Duda, Laurent C; Bruce, Peter G

    2016-07-01

    During the charging and discharging of lithium-ion-battery cathodes through the de- and reintercalation of lithium ions, electroneutrality is maintained by transition-metal redox chemistry, which limits the charge that can be stored. However, for some transition-metal oxides this limit can be broken and oxygen loss and/or oxygen redox reactions have been proposed to explain the phenomenon. We present operando mass spectrometry of (18)O-labelled Li1.2[Ni0.13(2+)Co0.13(3+)Mn0.54(4+)]O2, which demonstrates that oxygen is extracted from the lattice on charging a Li1.2[Ni0.13(2+)Co0.13(3+)Mn0.54(4+)]O2 cathode, although we detected no O2 evolution. Combined soft X-ray absorption spectroscopy, resonant inelastic X-ray scattering spectroscopy, X-ray absorption near edge structure spectroscopy and Raman spectroscopy demonstrates that, in addition to oxygen loss, Li(+) removal is charge compensated by the formation of localized electron holes on O atoms coordinated by Mn(4+) and Li(+) ions, which serve to promote the localization, and not the formation, of true O2(2-) (peroxide, O-O ~1.45 Å) species. The quantity of charge compensated by oxygen removal and by the formation of electron holes on the O atoms is estimated, and for the case described here the latter dominates. PMID:27325095

  4. Charge-compensation in 3d-transition-metal-oxide intercalation cathodes through the generation of localized electron holes on oxygen.

    PubMed

    Luo, Kun; Roberts, Matthew R; Hao, Rong; Guerrini, Niccoló; Pickup, David M; Liu, Yi-Sheng; Edström, Kristina; Guo, Jinghua; Chadwick, Alan V; Duda, Laurent C; Bruce, Peter G

    2016-07-01

    During the charging and discharging of lithium-ion-battery cathodes through the de- and reintercalation of lithium ions, electroneutrality is maintained by transition-metal redox chemistry, which limits the charge that can be stored. However, for some transition-metal oxides this limit can be broken and oxygen loss and/or oxygen redox reactions have been proposed to explain the phenomenon. We present operando mass spectrometry of (18)O-labelled Li1.2[Ni0.13(2+)Co0.13(3+)Mn0.54(4+)]O2, which demonstrates that oxygen is extracted from the lattice on charging a Li1.2[Ni0.13(2+)Co0.13(3+)Mn0.54(4+)]O2 cathode, although we detected no O2 evolution. Combined soft X-ray absorption spectroscopy, resonant inelastic X-ray scattering spectroscopy, X-ray absorption near edge structure spectroscopy and Raman spectroscopy demonstrates that, in addition to oxygen loss, Li(+) removal is charge compensated by the formation of localized electron holes on O atoms coordinated by Mn(4+) and Li(+) ions, which serve to promote the localization, and not the formation, of true O2(2-) (peroxide, O-O ~1.45 Å) species. The quantity of charge compensated by oxygen removal and by the formation of electron holes on the O atoms is estimated, and for the case described here the latter dominates.

  5. Localized surface plasmon induced enhancement of electron-hole generation with silver metal island at n-Al:ZnO/p-Cu{sub 2}O heterojunction

    SciTech Connect

    Kaur, Gurpreet Yadav, K. L.; Mitra, Anirban

    2015-08-03

    Localized surface plasmon induced generation of electron-hole pairs with inclusion of metal islands of noble metal like Ag can enhance the photocurrent. A heterostructure of n-Al:ZnO/p-Cu{sub 2}O with inclusion of Ag metalislands at the junction has been fabricated. I-V characteristic curve of these heterostructures shows a significant enhancement of photocurrent under the illumination (1.5 AMU). This enhancement of photocurrent is attributed to the supply of hot electrons generated in silver metal nanoislands. It has also been shown that inclusion of metal islands increases the absorption of solar spectrum in visible region at 500 nm. Enhancement of photocurrent may also be due to the direct resonance energy transfer from Localized Surface Plasmons of metal islands to Cu{sub 2}O.

  6. Origin of hole and electron traps in graphene oxide

    NASA Astrophysics Data System (ADS)

    Kotin, I. A.; Antonova, I. V.; Orlov, O. M.; Smagulova, S. A.

    2016-06-01

    Charge-carrier capture/emission processes proceeding with the participation of localized states in graphene oxide (GO) in test structures of Au/SiO2/GO/SiO2/Si were examined by charge deep-level transient spectroscopy (Q-DLTS). Two groups of traps capable of capturing both electrons and holes in GO were detected. The energy levels of these groups with reference to the electronic band structure of Si were found to be at EV + 0.75 eV (EC ‑ 0.37 eV) and EV + 0.55 eV (EC ‑ 0.55 eV). Such levels are proposed to be inherent to graphene islands in which charge carriers are emitted from energy levels in the vicinity of the Dirac point. Two groups of levels are suggested to be attributed to graphene islands, with and without p-doping with oxygen.

  7. The Local Black Hole Mass Function Derived from the MBH-P and the MBH-n Relations

    NASA Astrophysics Data System (ADS)

    Mutlu-Pakdil, Burçin; Seigar, Marc S.; Davis, Benjamin L.

    2016-10-01

    We present a determination of the supermassive black hole (SMBH) mass function for early- and late-type galaxies in the nearby universe (z < 0.0057), established from a volume-limited sample consisting of a statistically complete collection of the brightest spiral galaxies in the southern hemisphere. The sample is defined by limiting luminosity (redshift-independent) distance, D L = 25.4 Mpc, and a limiting absolute B-band magnitude, {{M}}B=-19.12. These limits define a sample of 140 spiral, 30 elliptical (E), and 38 lenticular (S0) galaxies. We established the Sérsic index distribution for early-type (E/S0) galaxies in our sample. Davis et al. established the pitch angle distribution for their sample, which is identical to our late-type (spiral) galaxy sample. We then used the pitch angle and the Sérsic index distributions in order to estimate the SMBH mass function for our volume-limited sample. The observational simplicity of our approach relies on the empirical relation between the mass of the central SMBH and the Sérsic index for an early-type galaxy or the logarithmic spiral-arm pitch angle for a spiral galaxy. Our SMBH mass function agrees well at the high-mass end with previous values in the literature. At the low-mass end, although inconsistencies exist in previous works that still need to be resolved, our work is more in line with expectations based on modeling of black hole evolution.

  8. Interfacial energy level alignments between low-band-gap polymer PTB7 and indium zinc oxide anode

    NASA Astrophysics Data System (ADS)

    Shin, Dongguen; Lee, Jeihyun; Park, Soohyung; Jeong, Junkyeong; Seo, Ki-Won; Kim, Hyo-Joong; Kim, Han-Ki; Choi, Min-Jun; Chung, Kwun-Bum; Yi, Yeonjin

    2015-09-01

    The interfacial energy level alignments between poly(thieno[3,4-b]-thiophene)-co-benzodithiophene (PTB7) and indium zinc oxide (IZO) were investigated. In situ ultraviolet photoemission spectroscopy measurements were conducted with the step-by-step deposition of PTB7 on IZO substrate. All spectral changes were analyzed between each deposition step, and interfacial energy level alignments were estimated. The hole barrier of standard ultraviolet-ozone treated IZO is 0.58 eV, which is lower than the value of 1.09 eV obtained for bare IZO. The effect of barrier reduction on the hole transport was also confirmed with electrical measurements of hole-dominated devices.

  9. Emergence of Space-Time Localization and Cosmic Decoherence:. More on Irreversible Time, Dark Energy, Anti-Matter and Black-Holes

    NASA Astrophysics Data System (ADS)

    Magnon, Anne

    2005-04-01

    anticipated by black-hole event horizons, cosmic censors able to shelter causal geometry). In analogy with black-hole singularities, the Big-Bang can be viewed as a geometric hint that a transition from incoherence to (causal space-time) localization and related coherence (comprehensibility), is taking place (space-time demolition, a reverse process towards incoherence or information recycling, is expected in the vicinity of singularities, as hinted by black-holes and related "time-machines"). A theory of the emergence of perception (and life?), in connection with observability and the function of partition (able to screen totality), is on its way [interface incoherence-coherence, sleeping and awaking states of localization, horizons of perception etc, are anticipated by black-hole event horizons, beyond which a non causal, dimensionless incoherent regime or memorization process, presents itself with the loss of localization, suggesting a unifying regime (ultimate energies?) hidden in cosmic potentialities]. The decoherence process presented here, suggests an ultimate interaction, expression of the logical relation of subsystems to totality, and to be identified to the flow of information or its recycling through cosmic jump (this is anticipated by the dissipation of distance or hierarchies on null-cones, themselves recycled with information and events). The geometric projection of this unified irreversible dynamics is expressed by unified Yang-Mills field equations (coupled to Einsteinian gravity). An ultimate form of action ("set"-volumes of information) presents itself, whose extrema can be achieved through extremal transfer of information and related partition of cells of information (thus anticipating the mitosis of living cells, possibly triggered at the non localizable level, as imposed by the logical regime of cosmic decoherence: participating subsystems ?). The matching of the objective and subjective facets of (information and) decoherences is perceived as contact

  10. Black holes

    PubMed Central

    Brügmann, B.; Ghez, A. M.; Greiner, J.

    2001-01-01

    Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries. PMID:11553801

  11. Nano- and microscale holes modulate cell-substrate adhesion, cytoskeletal organization, and -beta1 integrin localization in SV40 human corneal epithelial cells.

    PubMed

    Karuri, Nancy W; Porri, Teresa J; Albrecht, Ralph M; Murphy, Christopher J; Nealey, Paul F

    2006-12-01

    Human corneal epithelial cells (HCECs) interface with a basement membrane in vivo that possesses complex nanoscale topographic features. We report that synthetic substrates patterned with nano- and microscale holes differentially modulate the proliferation, shape and adhesion of SV40 human corneal epithelial cells (SV40-HCECs) as a function of feature size: 1) Cell proliferation was inhibited on nanoscale features (features size less than 800 nm in pitch) compared to microscale features or planar substrates in identical culture conditions. 2) Cells on nanoscale holes had a stellate morphology compared to those on microscale features that were more evenly spread. 3) Cells adhered more to nanoscale features than to microscale features when exposed to shear stress in a laminar flow chamber. Transmission electron microscopy showed that cells cultured on the 400 nm pitch patterns had longer and more numerous filopodia and retraction fibers than cells cultured on the 1600 nm pitch patterns. Immunogold labeling of -beta1 integrins revealed that these receptors were localized at the cell periphery and in the aforementioned cytoskeletal elements. Our findings indicate that surface discontinuities and the activation of mechanochemical cell signaling mechanisms may contribute to the observed responses exhibited by SV40-HCECs cultured on nano- and microscale topography.

  12. Seleno groups control the energy-level alignment between conjugated organic molecules and metals

    SciTech Connect

    Niederhausen, Jens; Heimel, Georg; Wilke, Andreas; Rabe, Jürgen P.; Duhm, Steffen; Bürker, Christoph; Schreiber, Frank; Xin, Qian; Vollmer, Antje; Kera, Satoshi; Ueno, Nobuo; Koch, Norbert

    2014-01-07

    The charge injection from metallic electrodes into hole transporting layers of organic devices often suffers from deviations from vacuum-level alignment at the interface. Even for weakly interacting cases, Pauli repulsion causes an interface dipole between the metal and conjugated organic molecules (COMs) (so called “push-back” or “cushion” effect), which leads notoriously to an increase of the hole injection barrier. On the other hand, for chalcogenol self assembled monolayers (SAMs) on metal surfaces, chemisorption via the formation of chalcogen-metal bonds is commonly observed. In these cases, the energy-level alignment is governed by chalcogen-derived interface states in the vicinity of the metal Fermi-level. In this work, we present X-ray and ultraviolet photoelectron spectroscopy data that demonstrate that the interfacial energy-level alignment mechanism found for chalcogenol SAMs also applies to seleno-functionalized COMs. This can be exploited to mitigate the push-back effect at metal contacts, notably also when COMs with low ionization energies are employed, permitting exceedingly low hole injection barriers, as shown here for the interfaces of tetraseleno-tetracene with Au(111), Ag(111), and Cu(111)

  13. Energy level alignment at the methylammonium lead iodide/copper phthalocyanine interface

    SciTech Connect

    Chen, Shi; Goh, Teck Wee; Sum, Tze Chien E-mail: Tzechien@ntu.edu.sg; Sabba, Dharani; Chua, Julianto; Mathews, Nripan; Huan, Cheng Hon Alfred E-mail: Tzechien@ntu.edu.sg

    2014-08-01

    The energy level alignment at the CH{sub 3}NH{sub 3}PbI{sub 3}/copper phthalocyanine (CuPc) interface is investigated by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). XPS reveal a 0.3 eV downward band bending in the CuPc film. UPS validate this finding and further reveal negligible interfacial dipole formation – verifying the viability of vacuum level alignment. The highest occupied molecular orbital of CuPc is found to be closer to the Fermi level than the valance band maximum of CH{sub 3}NH{sub 3}PbI{sub 3}, facilitating hole transfer from CH{sub 3}NH{sub 3}PbI{sub 3} to CuPc. However, subsequent hole extraction from CuPc may be impeded by the downward band bending in the CuPc layer.

  14. Tracing black hole accretion with SED decomposition and IR lines: from local galaxies to the high-z Universe

    NASA Astrophysics Data System (ADS)

    Gruppioni, C.; Berta, S.; Spinoglio, L.; Pereira-Santaella, M.; Pozzi, F.; Andreani, P.; Bonato, M.; De Zotti, G.; Malkan, M.; Negrello, M.; Vallini, L.; Vignali, C.

    2016-06-01

    We present new estimates of AGN accretion and star formation (SF) luminosity in galaxies obtained for the local 12 μm sample of Seyfert galaxies (12MGS), by performing a detailed broad-band spectral energy distribution (SED) decomposition including the emission of stars, dust heated by SF and a possible AGN dusty torus. Thanks to the availability of data from the X-rays to the sub-millimetre, we constrain and test the contribution of the stellar, AGN and SF components to the SEDs. The availability of Spitzer-InfraRed Spectrograph (IRS) low-resolution mid-infrared (mid-IR) spectra is crucial to constrain the dusty torus component at its peak wavelengths. The results of SED fitting are also tested against the available information in other bands: the reconstructed AGN bolometric luminosity is compared to those derived from X-rays and from the high excitation IR lines tracing AGN activity like [Ne V] and [O IV]. The IR luminosity due to SF and the intrinsic AGN bolometric luminosity are shown to be strongly related to the IR line luminosity. Variations of these relations with different AGN fractions are investigated, showing that the relation dispersions are mainly due to different AGN relative contribution within the galaxy. Extrapolating these local relations between line and SF or AGN luminosities to higher redshifts, by means of recent Herschel galaxy evolution results, we then obtain mid- and far-IR line luminosity functions useful to estimate how many star-forming galaxies and AGN we expect to detect in the different lines at different redshifts and luminosities with future IR facilities (e.g. JWST, SPICA).

  15. Theory of Energy Level Tuning in Quantum Dots by Surfactants

    NASA Astrophysics Data System (ADS)

    Zherebetskyy, Danylo; Wang, Lin-Wang; Materials Sciences Division, Lawrence Berkeley National Laboratory Team

    2015-03-01

    Besides quantum confinement that provides control of the quantum dot (QD) band gap, surface ligands allow control of the absolute energy levels. We theoretically investigate energy level tuning in PbS QD by surfactant exchange. We perform direct calculations of real-size QD with various surfactants within the frame of the density functional theory and explicitly analyze the influence of the surfactants on the electronic properties of the QD. This work provides a hint for predictable control of the absolute energy levels and their fine tuning within 3 eV range by modification of big and small surfactants that simultaneously passivate the QD surface.

  16. Energy level alignment in TiO2/metal sulfide/polymer interfaces for solar cell applications.

    PubMed

    Lindblad, Rebecka; Cappel, Ute B; O'Mahony, Flannan T F; Siegbahn, Hans; Johansson, Erik M J; Haque, Saif A; Rensmo, Håkan

    2014-08-28

    Semiconductor sensitized solar cell interfaces have been studied with photoelectron spectroscopy to understand the interfacial electronic structures. In particular, the experimental energy level alignment has been determined for complete TiO2/metal sulfide/polymer interfaces. For the metal sulfides CdS, Sb2S3 and Bi2S3 deposited from single source metal xanthate precursors, it was shown that both driving forces for electron injection into TiO2 and hole transfer to the polymer decrease for narrower bandgaps. The energy level alignment results were used in the discussion of the function of solar cells with the same metal sulfides as light absorbers. For example Sb2S3 showed the most favourable energy level alignment with 0.3 eV driving force for electron injection and 0.4 eV driving force for hole transfer and also the most efficient solar cells due to high photocurrent generation. The energy level alignment of the TiO2/Bi2S3 interface on the other hand showed no driving force for electron injection to TiO2, and the performance of the corresponding solar cell was very low.

  17. "Piekara's Chair": Mechanical Model for Atomic Energy Levels.

    ERIC Educational Resources Information Center

    Golab-Meyer, Zofia

    1991-01-01

    Uses the teaching method of models or analogies, specifically the model called "Piekara's chair," to show how teaching classical mechanics can familiarize students with the notion of energy levels in atomic physics. (MDH)

  18. Housing Electrons: Relating Quantum Numbers, Energy Levels, and Electron Configurations.

    ERIC Educational Resources Information Center

    Garofalo, Anthony

    1997-01-01

    Presents an activity that combines the concepts of quantum numbers and probability locations, energy levels, and electron configurations in a concrete, hands-on way. Uses model houses constructed out of foam board and colored beads to represent electrons. (JRH)

  19. Calculation of Rydberg energy levels for the francium atom

    NASA Astrophysics Data System (ADS)

    Huang, Shi-Zhong; Chu, Jin-Min

    2010-06-01

    Based on the weakest bound electron potential model theory, the Rydberg energy levels and quantum defects of the np2Po1/2 (n = 7-50) and np2Po3/2 (n = 7-50) spectrum series for the francium atom are calculated. The calculated results are in excellent agreement with the 48 measured levels, and 40 energy levels for highly excited states are predicted.

  20. Retinal holes.

    PubMed

    Foos, R Y

    1978-09-01

    Holes of the peripheral retina, defined as full-thickness breaks of trophic origin with no associated flap or free operculum, were found in 136 (2.4%) eyes from 2,800 autopsied subjects. Primary retinal holes (those with no indication of a proximal causative lesion and with no lattice degeneration in either eye) occurred in only eight of the 5,600 eyes studied; all were unilateral, single, less than 0.25 disk diameter in size, within the basal zone, and in eyes from elderly subjects. Secondary holes were found in 128 (2.3%) of eyes and of these, lattice degeneration was the most common cause (103). Other lesions complicated by hole formation included zonular traction tufts (10), chorioretinitis (9), meridional folds (3), and pavingstone degeneration (2). Retinal holes in surgically aphakic eyes did not differ qualitatively or quantitatively from those in age-matched phakic eyes.

  1. Energy level realignment in weakly interacting donor-acceptor binary molecular networks.

    PubMed

    Zhong, Jian-Qiang; Qin, Xinming; Zhang, Jia-Lin; Kera, Satoshi; Ueno, Nobuo; Wee, Andrew Thye Shen; Yang, Jinlong; Chen, Wei

    2014-02-25

    Understanding the effect of intermolecular and molecule-substrate interactions on molecular electronic states is key to revealing the energy level alignment mechanism at organic-organic heterojunctions or organic-inorganic interfaces. In this paper, we investigate the energy level alignment mechanism in weakly interacting donor-acceptor binary molecular superstructures, comprising copper hexadecafluorophthalocyanine (F16CuPc) intermixed with copper phthalocyanine (CuPc), or manganese phthalocynine (MnPc) on graphite. The molecular electronic structures have been systematically studied by in situ ultraviolet photoelectron spectroscopy (UPS) and low-temperature scanning tunneling microscopy/spectroscopy (LT-STM/STS) experiments and corroborated by density functional theory (DFT) calculations. As demonstrated by the UPS and LT-STM/STS measurements, the observed unusual energy level realignment (i.e., a large downward shift in donor HOMO level and a corresponding small upward shift in acceptor HOMO level) in the CuPc-F16CuPc binary superstructures originates from the balance between intermolecular and molecule-substrate interactions. The enhanced intermolecular interactions through the hydrogen bonding between neighboring CuPc and F16CuPc can stabilize the binary superstructures and modify the local molecular electronic states. The obvious molecular energy level shift was explained by gap-state-mediated interfacial charge transfer. PMID:24433044

  2. Calibration of Electric Field Induced Energy Level Shifts in Argon

    NASA Astrophysics Data System (ADS)

    Hebner, Greg

    1999-10-01

    Argon is a commonly used gas in a number of discharges. As such it is an ideal candidate for spectroscopic based electric field measurements within the sheath and bulk discharge regions. Recently, measurements demonstrated the use of the Stark induced shifts of high lying energy levels in Argon to make spatially and temporally resolved electric field measurements [1]. However, that method relied on the cross calibration of known and calculable shifts in helium discharges to calibrate, in-situ, the energy level shifts in Argon. This poster shows the use of an atomic beam system to calibrate the electric field induced shift of high lying energy levels directly. In addition, data on very high lying argon levels, up to the 20 F manifold, were obtained. Comparison of our electric field induced energy level shift calibration curves with previous work will be shown. The possibility of using this system to calibrate energy level shifts in other gases of technological interest to the microelectronics and lighting industry will be discussed. [1]. J. B. Kim, K. Kawamura, Y. W. Choi, M. D. Bowden, K. Muraoka and V. Helbig, IEEE Transactions on Plasma Science, 26(5), 1556 (1998). This work was performed at Sandia National Laboratories and supported by the United States Department of Energy (DE-AC04-94AL85000).

  3. Real-space localization and quantification of hole distribution in chain-ladder Sr3Ca11Cu24O41 superconductor

    PubMed Central

    Bugnet, Matthieu; Löffler, Stefan; Hawthorn, David; Dabkowska, Hanna A.; Luke, Graeme M.; Schattschneider, Peter; Sawatzky, George A.; Radtke, Guillaume; Botton, Gianluigi A.

    2016-01-01

    Understanding the physical properties of the chain-ladder Sr3Ca11Cu24O41 hole-doped superconductor has been precluded by the unknown hole distribution among chains and ladders. We use electron energy-loss spectrometry (EELS) in a scanning transmission electron microscope (STEM) at atomic resolution to directly separate the contributions of chains and ladders and to unravel the hole distribution from the atomic scale variations of the O-K near-edge structures. The experimental data unambiguously demonstrate that most of the holes lie within the chain layers. A quantitative interpretation supported by inelastic scattering calculations shows that about two holes are located in the ladders, and about four holes in the chains, shedding light on the electronic structure of Sr3Ca11Cu24O41. Combined atomic resolution STEM-EELS and inelastic scattering calculations is demonstrated as a powerful approach toward a quantitative understanding of the electronic structure of cuprate superconductors, offering new possibilities for elucidating their physical properties. PMID:27051872

  4. Real-space localization and quantification of hole distribution in chain-ladder Sr3Ca11Cu24O41 superconductor.

    PubMed

    Bugnet, Matthieu; Löffler, Stefan; Hawthorn, David; Dabkowska, Hanna A; Luke, Graeme M; Schattschneider, Peter; Sawatzky, George A; Radtke, Guillaume; Botton, Gianluigi A

    2016-03-01

    Understanding the physical properties of the chain-ladder Sr3Ca11Cu24O41 hole-doped superconductor has been precluded by the unknown hole distribution among chains and ladders. We use electron energy-loss spectrometry (EELS) in a scanning transmission electron microscope (STEM) at atomic resolution to directly separate the contributions of chains and ladders and to unravel the hole distribution from the atomic scale variations of the O-K near-edge structures. The experimental data unambiguously demonstrate that most of the holes lie within the chain layers. A quantitative interpretation supported by inelastic scattering calculations shows that about two holes are located in the ladders, and about four holes in the chains, shedding light on the electronic structure of Sr3Ca11Cu24O41. Combined atomic resolution STEM-EELS and inelastic scattering calculations is demonstrated as a powerful approach toward a quantitative understanding of the electronic structure of cuprate superconductors, offering new possibilities for elucidating their physical properties. PMID:27051872

  5. Real-space localization and quantification of hole distribution in chain-ladder Sr3Ca11Cu24O41 superconductor.

    PubMed

    Bugnet, Matthieu; Löffler, Stefan; Hawthorn, David; Dabkowska, Hanna A; Luke, Graeme M; Schattschneider, Peter; Sawatzky, George A; Radtke, Guillaume; Botton, Gianluigi A

    2016-03-01

    Understanding the physical properties of the chain-ladder Sr3Ca11Cu24O41 hole-doped superconductor has been precluded by the unknown hole distribution among chains and ladders. We use electron energy-loss spectrometry (EELS) in a scanning transmission electron microscope (STEM) at atomic resolution to directly separate the contributions of chains and ladders and to unravel the hole distribution from the atomic scale variations of the O-K near-edge structures. The experimental data unambiguously demonstrate that most of the holes lie within the chain layers. A quantitative interpretation supported by inelastic scattering calculations shows that about two holes are located in the ladders, and about four holes in the chains, shedding light on the electronic structure of Sr3Ca11Cu24O41. Combined atomic resolution STEM-EELS and inelastic scattering calculations is demonstrated as a powerful approach toward a quantitative understanding of the electronic structure of cuprate superconductors, offering new possibilities for elucidating their physical properties.

  6. Temperature dependent energy levels of methylammonium lead iodide perovskite

    SciTech Connect

    Foley, Benjamin J.; Marlowe, Daniel L.; Choi, Joshua J. E-mail: mgupta@virginia.edu; Sun, Keye; Gupta, Mool C. E-mail: mgupta@virginia.edu; Saidi, Wissam A.; Scudiero, Louis E-mail: mgupta@virginia.edu

    2015-06-15

    Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature.

  7. Efficiencies of thermodynamics when temperature-dependent energy levels exist.

    PubMed

    Yamano, Takuya

    2016-03-14

    Based on a generalized form of the second law of thermodynamics, in which the temperature-dependent energy levels of a system are appropriately included in entropy generation, we show that the effect reasonably appears in efficiencies of thermodynamic processes. PMID:26890276

  8. Degeneracy of energy levels of pseudo-Gaussian oscillators

    SciTech Connect

    Iacob, Theodor-Felix; Iacob, Felix; Lute, Marina

    2015-12-07

    We study the main features of the isotropic radial pseudo-Gaussian oscillators spectral properties. This study is made upon the energy levels degeneracy with respect to orbital angular momentum quantum number. In a previous work [6] we have shown that the pseudo-Gaussian oscillators belong to the class of quasi-exactly solvable models and an exact solution has been found.

  9. Spin polarization and magnetic dichroism in photoemission from core and valence states in localized magnetic systems. IV. Core-hole polarization in resonant photoemission

    NASA Astrophysics Data System (ADS)

    van der Laan, Gerrit; Thole, B. T.

    1995-12-01

    A simple theory is presented for core-hole polarization probed by resonant photoemission in a two-steps approximation. After excitation from a core level to the valence shell, the core hole decays into two shallower core holes under emission of an electron. The nonspherical core hole and the final state selected cause a specific angle and spin distribution of the emitted electron. The experiment is characterized by the ground-state moments, the polarization of the light, and the spin and angular distribution of the emitted electron. The intensity is a sum over ground-state expectation values of tensor operators times the probability to create a polarized core hole using polarized light, times the probability for decay of such a core hole into the final state. We give general expressions for the angle- and spin-dependent intensities in various regimes of Coulomb and spin-orbit interaction: LS, LSJ, and jjJ coupling. The core-polarization analysis, which generalizes the use of sum rules in x-ray absorption spectroscopy where the integrated peak intensities give ground-state expectation values of the spin and orbital moment operators, makes it possible to measure different linear combinations of these operators. As an application the 2p3/23p3p decay in ferromagnetic nickel is calculated using Hartree-Fock values for the radial matrix elements and phase factors, and compared with experiment, the dichroism is smaller in the 3P final state but stronger in the 1D, 1S peak.

  10. Calculation of energy levels, {ital E}1 transition amplitudes, and parity violation in francium

    SciTech Connect

    Dzuba, V.A.; Flambaum, V.V.; Sushkov, O.P.

    1995-05-01

    Many-body perturbation theory in the screened Coulomb interaction was used to calculate energy levels, {ital E}1 trransition amplitudes, and the parity-nonconserving (PNC) {ital E}1 amplitude of the 7{ital s}-8{ital s} transition in francium. The method takes into account the core-polarization effect, the second-order correlations, and the three dominating sequences of higher-order correlation diagrams: screening of the electron-electron interaction, particle-hole interaction, and the iterations of the self-energy operator. The result for the PNC amplitude for {sup 223}Fr is {ital E}1(7{ital s}-8{ital s})=(1.59{plus_minus}{similar_to}1%){times}10{sup {minus}10}{ital iea}{sub {ital B}}({minus}{ital Q}{sub {ital W}}/{ital N}), where {ital Q}{sub {ital W}} is the weak charge of the nucleus, {ital N}=136 is the number of neutrons, {ital e}={vert_bar}{ital e}{vert_bar} is the elementary charge, and {ital a}{sub {ital B}} is the Bohr radius. Our prediction for the position of the 8{ital s} energy level of Fr, which has not been measured yet, is 13 110 cm{sup {minus}1} below the limit of the continuous spectrum. The accuracy of the calculations was controlled by comparison with available experimental data and analogous calculations for cesium. It is estimated to be {similar_to}0.1% for the energy levels and {similar_to}1% for the transition amplitudes.

  11. String duality and black holes

    NASA Astrophysics Data System (ADS)

    Kalara, S.; Nanopoulos, D. V.

    1991-09-01

    In the context of (semi) classical general relativity, the physics of black holes poses many unanswered and unsettling questions. Notable among them are the loss of quantum coherence, which casts doubts on the basic foundations of quantum mechanics, and the understanding of the enormous entropy carried by black holes which is at odds with strong ``no hair'' theorems. We point out that in string theory, black-hole type solutions (S-black holes) carry local discrete charges inherited from the duality symmetries of the string, which allow S-black holes to carry ``quantum hair''. It is further noted that the conservation of the discrete charges and the presence of quantum hair precludes the information about a quantum state from being completely lost in the black hole thus rescuing quantum coherence. We also note that a large number of quantum hair carried by S-black holes may explain their enormous entropy, i.e. it is the duality symmetry of the string theory which redeems outstanding problems of black-hole dynamics. We also discuss a possible description of black holes as solitons of string theory. Supported in part by DOE Grant DE-AS05-81 ER40039.

  12. How to Draw Energy Level Diagrams in Excitonic Solar Cells.

    PubMed

    Zhu, X-Y

    2014-07-01

    Emerging photovoltaic devices based on molecular and nanomaterials are mostly excitonic in nature. The initial absorption of a photon in these materials creates an exciton that can subsequently dissociate in each material or at their interfaces to give charge carriers. Any attempt at mechanistic understanding of excitonic solar cells must start with drawing energy level diagrams. This seemingly elementary exercise, which is described in textbooks for inorganic solar cells, has turned out to be a difficult subject in the literature. The problem stems from conceptual confusion of single-particle energy with quasi-particle energy and the misleading practice of mixing the two on the same energy level diagram. Here, I discuss how to draw physically accurate energy diagrams in excitonic solar cells using only single-particle energies (ionization potentials and electron affinities) of both ground and optically excited states. I will briefly discuss current understanding on the electronic energy landscape responsible for efficient charge separation in excitonic solar cells.

  13. Energy level transitions of gas in a 2D nanopore

    SciTech Connect

    Grinyaev, Yurii V.; Chertova, Nadezhda V.; Psakhie, Sergei G.

    2015-10-27

    An analytical study of gas behavior in a 2D nanopore was performed. It is shown that the temperature dependence of gas energy can be stepwise due to transitions from one size-quantized subband to another. Taking into account quantum size effects results in energy level transitions governed by the nanopore size, temperature and gas density. This effect leads to an abrupt change of gas heat capacity in the nanopore at the above varying system parameters.

  14. Energy levels scheme simulation of divalent cobalt doped bismuth germanate

    NASA Astrophysics Data System (ADS)

    Andreici, Emiliana-Laura; Petkova, Petya; Avram, Nicolae M.

    2015-12-01

    The aim of this paper is to simulate the energy levels scheme for Bismuth Germanate (BGO) doped with divalent cobalt, in order to give a reliable explanation for spectral experimental data. In the semiempirical crystal field theory we first modeled the Crystal Field Parameters (CFPs) of BGO:Cr2+ system, in the frame of Exchange Charge Model (ECM), with actually site symmetry of the impurity ions after doping. The values of CFPs depend on the geometry of doped host matrix and by parameter G of ECM. First, we optimized the geometry of undoped BGO host matrix and afterwards, that of doped BGO with divalent cobalt. The charges effect of ligands and covalence bonding between cobalt cations and oxygen anions, in the cluster approach, also were taken into account. With the obtained values of the CFPs we simulate the energy levels scheme of cobalt ions, by diagonalizing the matrix of the doped crystal Hamiltonian. Obviously, energy levels and estimated Racah parameters B and C were compared with the experimental spectroscopic data and discussed. Comparison of obtained results with experimental data shows quite satisfactory, which justify the model and simulation schemes used for the title system.

  15. Energy levels, lifetimes and radiative data of Ba XXVI

    NASA Astrophysics Data System (ADS)

    Singh, A. K.; Goyal, Arun; Khatri, Indu; Aggarwal, Sunny; Sharma, Rinku; Mohan, Man

    2016-05-01

    We report an extensive and an elaborate theoretical study of atomic data for Ba XXVI by considering Singlet, Doublet and Triplet (SDT) electron excitations within N-shell and single excitations from N-shell to O-shell. We have calculated energy levels and lifetimes for lowest 110 fine structure levels by using Multi-configuration Dirac-Fock method (MCDF). We have also considered Quantum Electrodynamics (QED) and Breit corrections in our calculations. We have presented the radiative data for electric and magnetic dipole (E1, M1) and quadrupole (E2, M2) transitions among lowest 110 levels. We have made comparisons of our calculated excitation energies and EUV (Extreme Ultraviolet) transition wavelengths with experimentally observed energy levels and wavelengths and achieved good agreement. We have also computed energy levels by performing similar relativistic distorted wave calculations using Flexible Atomic Code (FAC). Additionally, we have provided new atomic data for Ba XXVI which are not published elsewhere in the literature. We believe that our results may be beneficial in fusion plasma research and astrophysical investigations and applications.

  16. Energy levels scheme simulation of divalent cobalt doped bismuth germanate

    SciTech Connect

    Andreici, Emiliana-Laura; Petkova, Petya; Avram, Nicolae M.

    2015-12-07

    The aim of this paper is to simulate the energy levels scheme for Bismuth Germanate (BGO) doped with divalent cobalt, in order to give a reliable explanation for spectral experimental data. In the semiempirical crystal field theory we first modeled the Crystal Field Parameters (CFPs) of BGO:Cr{sup 2+} system, in the frame of Exchange Charge Model (ECM), with actually site symmetry of the impurity ions after doping. The values of CFPs depend on the geometry of doped host matrix and by parameter G of ECM. First, we optimized the geometry of undoped BGO host matrix and afterwards, that of doped BGO with divalent cobalt. The charges effect of ligands and covalence bonding between cobalt cations and oxygen anions, in the cluster approach, also were taken into account. With the obtained values of the CFPs we simulate the energy levels scheme of cobalt ions, by diagonalizing the matrix of the doped crystal Hamiltonian. Obviously, energy levels and estimated Racah parameters B and C were compared with the experimental spectroscopic data and discussed. Comparison of obtained results with experimental data shows quite satisfactory, which justify the model and simulation schemes used for the title system.

  17. Distorted stationary rotating black holes

    NASA Astrophysics Data System (ADS)

    Shoom, Andrey A.

    2015-03-01

    We study the interior of distorted stationary rotating black holes on the example of a Kerr black hole distorted by external static and axisymmetric mass distribution. We show that there is a duality transformation between the outer and inner horizons of the black hole, which is different from that of an electrically charged static distorted black hole. The duality transformation is directly related to the discrete symmetry of the space-time. The black hole horizon areas, surface gravity, and angular momentum satisfy the Smarr formula constructed for both the horizons. We formulate the zeroth, the first, and the second laws of black hole thermodynamics for both the horizons of the black hole and show the correspondence between the local and the global forms of the first law. The Smarr formula and the laws of thermodynamics formulated for both the horizons are related by the duality transformation. The distortion is illustrated on the example of a quadrupole and octupole fields. The distortion fields noticeably affect the proper time of a free fall from the outer to the inner horizon of the black hole along the symmetry semiaxes. There is some minimal nonzero value of the quadrupole and octupole moments when the time becomes minimal. The minimal proper time indicates the closest approach of the horizons due to the distortion.

  18. Accurate energy levels for singly ionized platinum (Pt II)

    NASA Technical Reports Server (NTRS)

    Reader, Joseph; Acquista, Nicolo; Sansonetti, Craig J.; Engleman, Rolf, Jr.

    1988-01-01

    New observations of the spectrum of Pt II have been made with hollow-cathode lamps. The region from 1032 to 4101 A was observed photographically with a 10.7-m normal-incidence spectrograph. The region from 2245 to 5223 A was observed with a Fourier-transform spectrometer. Wavelength measurements were made for 558 lines. The uncertainties vary from 0.0005 to 0.004 A. From these measurements and three parity-forbidden transitions in the infrared, accurate values were determined for 28 even and 72 odd energy levels of Pt II.

  19. Dumb holes: analogues for black holes.

    PubMed

    Unruh, W G

    2008-08-28

    The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.

  20. Plasma electron hole kinematics. I. Momentum conservation

    NASA Astrophysics Data System (ADS)

    Hutchinson, I. H.; Zhou, C.

    2016-08-01

    We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, which behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

  1. Superconducting electron and hole lenses

    NASA Astrophysics Data System (ADS)

    Cheraghchi, H.; Esmailzadeh, H.; Moghaddam, A. G.

    2016-06-01

    We show how a superconducting region (S), sandwiched between two normal leads (N), in the presence of barriers, can act as a lens for propagating electron and hole waves by virtue of the so-called crossed Andreev reflection (CAR). The CAR process, which is equivalent to Cooper pair splitting into two N electrodes, provides a unique possibility of constructing entangled electrons in solid state systems. When electrons are locally injected from an N lead, due to the CAR and normal reflection of quasiparticles by the insulating barriers at the interfaces, sequences of electron and hole focuses are established inside another N electrode. This behavior originates from the change of momentum during electron-hole conversion beside the successive normal reflections of electrons and holes due to the barriers. The focusing phenomena studied here are fundamentally different from the electron focusing in other systems, such as graphene p-n junctions. In particular, due to the electron-hole symmetry of the superconducting state, the focusing of electrons and holes is robust against thermal excitations. Furthermore, the effects of the superconducting layer width, the injection point position, and barrier strength are investigated on the focusing behavior of the junction. Very intriguingly, it is shown that by varying the barrier strength, one can separately control the density of electrons or holes at the focuses.

  2. Energy levels of exciton in a gapped graphene sheet

    NASA Astrophysics Data System (ADS)

    Fallah, Farhang; Esmaeilzadeh, Mahdi

    2013-08-01

    A theory is presented for exciton formation in a graphene sheet using the center-of-mass approximation. The energy levels and wavefunctions of exciton are calculated analytically which show that the exciton can form if the band gap of graphene is not zero. We show that the energy gap of graphene plays the role of the mass which if not zero, leads to formation of the excitons. It is shown that the main quantum number of the exciton ground state changes with the graphene dielectric constant. Also, all of the states are found to be four-fold degenerate. The binding energy of exciton can reach as high as 1/4 of the energy gap of graphene which is notable among the conventional quasi-2D systems. This result can play an important rule in the photonics of graphene.

  3. Energy levels and radiative rates for transitions in Ga XXIV

    SciTech Connect

    El-Sayed, Fatma

    2012-07-15

    Energy levels, transition probabilities, oscillator strengths, line strengths, and lifetimes have been calculated for Oxygen-like Gallium, Ga XXIV. The configurations 2s{sup 2}2p{sup 4}, 2s2p{sup 5}, 2p{sup 6}, 2s2p{sup 4}3 Script-Small-L , 2s{sup 2}2p{sup 3}3 Script-Small-L , and 2p{sup 5}3 Script-Small-L were used in calculations and 226 fine-structure levels were obtained. The fully relativistic GRASP code has been adopted, and results are reported for all electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions among the lowest 226 levels of Ga XXIV, belonging to the n{<=}3 configurations. Comparisons have been made with earlier available theoretical and experimental results.

  4. Non-chiral 2d CFT with integer energy levels

    NASA Astrophysics Data System (ADS)

    Ashrafi, M.; Loran, F.

    2016-09-01

    The partition function of 2d conformal field theory is a modular invariant function. It is known that the partition function of a holomorphic CFT whose central charge is a multiple of 24 is a polynomial in the Klein function. In this paper, by using the medium temperature expansion we show that every modular invariant partition function can be mapped to a holomorphic partition function whose structure can be determined similarly. We use this map to study partition function of CFTs with half-integer left and right conformal weights. We show that the corresponding left and right central charges are necessarily multiples of 4. Furthermore, the degree of degeneracy of high-energy levels can be uniquely determined in terms of the degeneracy in the low energy states.

  5. News and Views: Keith Mason moves to UK Space Agency; Pristine gas from dawn of time; Discovering local dark skies; Planet collisions may generate black hole dust

    NASA Astrophysics Data System (ADS)

    2011-12-01

    Keith Mason stepped down from his role as CEO of STFC on 1 November in order to take up a post at the UK Space Agency until 31 March 2012, advising on steps needed to leverage the research base to maximize the economic growth of the space sector. He is succeeded at STFC by John Womersley. Diffuse gas clouds composed of hydrogen and deuterium have been detected in deep space-potential reservoirs of pristine material left over from the Big Bang. Finding places where skies are dark enough to see stars and planets will be easier thanks to a national initiative funded by the Big Lottery Fund and led by the STFC. Clouds of dust around the centres of galaxies where supermassive black holes lurk may come from collisions between planets and asteroids-much as zodiacal dust in the solar system comes from comet and asteroid collisions.

  6. Correlation between the energy level structure of cerium-doped yttrium aluminum garnet and luminescent behavior at varying temperatures

    NASA Astrophysics Data System (ADS)

    Song, Zhen; Liu, Xiaolang; He, Lizhu; Liu, Q. L.

    2016-05-01

    Luminescent spectra of cerium-doped yttrium aluminum garnet are measured at varying temperatures. It is found that the two excitation peaks demonstrate a reverse trend as the temperature rises, and the breadth of the high-energy emission peak experiences an abrupt widening. These effects could be directly linked to the energy level scheme of Ce3+ under the crystal field of local symmetry. Moreover, an alternative fitting function is provided which could effectively resolve the emission curve.

  7. Mechanism of hole doping into hydrogen terminated diamond by the adsorption of inorganic molecule

    NASA Astrophysics Data System (ADS)

    Takagi, Yoshiteru; Shiraishi, Kenji; Kasu, Makoto; Sato, Hisashi

    2013-03-01

    We revealed a mechanism of hole doping into hydrogen (H) terminated diamond by the adsorption of inorganic molecules, based on first-principle calculation. Electron transfer from H-terminated diamond to adsorbate molecules was found in the case that the energy level of unoccupied molecular orbitals in an adsorbate molecule is below or around the valence band maximum of H-terminated diamond. The amount of doped hole carriers depends on the energy level of unoccupied molecular orbital of adsorbate molecules. The mechanism can explain the experimentally observed dependence of increasing hole sheet concentration at H-terminated diamond surface on the species of adsorbate molecule.

  8. On the Thermal Property of Arbitrarily Accelerating Charged Black Hole with a New Tortoise Coordinate Transformation

    NASA Astrophysics Data System (ADS)

    Zhenfeng, Niu; Wenbiao, Liu

    2006-07-01

    After a new tortoise coordinate transformation is adopted, the entropy and non-thermal radiation of an arbitrarily accelerating charged black hole are discussed as an example of non-stationary black holes. The same cut-off relation is chosen as static case, which is independent of space-time, and then the entropy of the non-stationary black hole is also proportional to the area of its event horizon. Meanwhile, the crossing of the particle energy levels near the event horizon is studied, the representative of the maximum value of the crossing energy levels is the same as the usual tortoise coordinate transformation.

  9. Interaction Determined Electron Energy Levels in One-Dimension

    NASA Astrophysics Data System (ADS)

    Pepper, Michael; Kumar, Sanjeev; Thomas, Kalarikad; Smith, Luke; Creeth, Graham; Farrer, Ian; Ritchie, David; Jones, Geraint; Jonathan, Griffiths; UCL Collaboration; Cavendish Laboratory Collaboration

    2015-03-01

    We have investigated electron transport in a quasi-one dimensional electron gas in the GaAs-AlGaAs heterostructure designed so that the confinement potential can be progressively weakened. This causes the energy levels to decrease in energy relative to each other, however this decrease occurs at different rates, a feature attributed to the energy being determined by both confinement and the electron-electron repulsion which varies with the shape of the wavefunction. It is found that the initial ground state crosses the higher levels so resulting in missing plateaux of quantised conductance. A change in the nature of the ground state to a more extended form causes an increase in the capacitance between the confining gates and the electrons. Both crossings and anti-crossings of the levels are found and these will be discussed along with other consequences of the form of the level interactions. The effects of level crossing on the spin dependent 0.7 structure will be presented. Supported by EPSRC (UK).

  10. Stationary black holes: large D analysis

    NASA Astrophysics Data System (ADS)

    Suzuki, Ryotaku; Tanabe, Kentaro

    2015-09-01

    We consider the effective theory of large D stationary black holes. By solving the Einstein equations with a cosmological constant using the 1 /D expansion in near zone of the black hole we obtain the effective equation for the stationary black hole. The effective equation describes the Myers-Perry black hole, bumpy black holes and, possibly, the black ring solution as its solutions. In this effective theory the black hole is represented as an embedded membrane in the background, e.g., Minkowski or Anti-de Sitter spacetime and its mean curvature is given by the surface gravity redshifted by the background gravitational field and the local Lorentz boost. The local Lorentz boost property of the effective equation is observed also in the metric itself. In fact we show that the leading order metric of the Einstein equation in the 1 /D expansion is generically regarded as a Lorentz boosted Schwarzschild black hole. We apply this Lorentz boost property of the stationary black hole solution to solve perturbation equations. As a result we obtain an analytic formula for quasinormal modes of the singly rotating Myers-Perry black hole in the 1 /D expansion.

  11. The Recovery of the Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2004-01-01

    The ozone hole is a massive loss of ozone that annually occurs over Antarctica during the Austral spring (August-November). Man-made chlorine and bromine compounds cause the ozone hole. As opposed to local urban pollution, the hole illustrates how man-made chemicals can affect the atmosphere over enormous regions remote from their release point. These chlorine and bromine gases have long lifetimes in the atmosphere; hence, the ozone hole will slowly recover into the next few decades. In this talk I will briefly cover some of the history of the Antarctic ozone hole and the theory behind the phenomena. I will then discuss the recovery of ozone over Antarctica. State-of-the-art computer models project the recovery of the ozone hole to 1980 levels by about 2050. However, this recovery may be affected by greenhouse warming.

  12. Energy level broadening of defects causing nonideality in nearly ideal Si Schottky barriers

    NASA Astrophysics Data System (ADS)

    Maeda, Keiji

    2004-10-01

    We have proposed a mechanism of the local Schottky barrier height (SBH) lowering to explain the nonideal characteristics in Si SBs. Positively charged defects close to the M/S interface induce image charge in the metal-induced gap states (MIGS) and lower the SBH. Based on this mechanism, the inhomogeneous potential distributions in the proximity of the MIGS are calculated in agreement with the I- V characteristics. The energy level of the defect, identified with Si self-interstitial, is in agreement with the theoretical value. The energy width of the defect is nearly equal to the standard deviation in the Gaussian distribution describing the SBH inhomogeneity. Thus, the propriety of the model is confirmed.

  13. Hole spins in an InAs/GaAs quantum dot molecule subject to lateral electric fields

    NASA Astrophysics Data System (ADS)

    Ma, Xiangyu; Bryant, Garnett W.; Doty, Matthew F.

    2016-06-01

    There has been tremendous progress in manipulating electron and hole-spin states in quantum dots or quantum dot molecules (QDMs) with growth-direction (vertical) electric fields and optical excitations. However, the response of carriers in QDMs to an in-plane (lateral) electric field remains largely unexplored. We computationally explore spin-mixing interactions in the molecular states of single holes confined in vertically stacked InAs/GaAs QDMs using atomistic tight-binding simulations. We systematically investigate QDMs with different geometric structure parameters and local piezoelectric fields. We observe both a relatively large Stark shift and a change in the Zeeman splitting as the magnitude of the lateral electric field increases. Most importantly, we observe that lateral electric fields induce hole-spin mixing with a magnitude that increases with increasing lateral electric field over a moderate range. These results suggest that applied lateral electric fields could be used to fine tune and manipulate, in situ, the energy levels and spin properties of single holes confined in QDMs.

  14. Sleep and brain energy levels: ATP changes during sleep.

    PubMed

    Dworak, Markus; McCarley, Robert W; Kim, Tae; Kalinchuk, Anna V; Basheer, Radhika

    2010-06-30

    Sleep is one of the most pervasive biological phenomena, but one whose function remains elusive. Although many theories of function, indirect evidence, and even common sense suggest sleep is needed for an increase in brain energy, brain energy levels have not been directly measured with modern technology. We here report that ATP levels, the energy currency of brain cells, show a surge in the initial hours of spontaneous sleep in wake-active but not in sleep-active brain regions of rat. The surge is dependent on sleep but not time of day, since preventing sleep by gentle handling of rats for 3 or 6 h also prevents the surge in ATP. A significant positive correlation was observed between the surge in ATP and EEG non-rapid eye movement delta activity (0.5-4.5 Hz) during spontaneous sleep. Inducing sleep and delta activity by adenosine infusion into basal forebrain during the normally active dark period also increases ATP. Together, these observations suggest that the surge in ATP occurs when the neuronal activity is reduced, as occurs during sleep. The levels of phosphorylated AMP-activated protein kinase (P-AMPK), well known for its role in cellular energy sensing and regulation, and ATP show reciprocal changes. P-AMPK levels are lower during the sleep-induced ATP surge than during wake or sleep deprivation. Together, these results suggest that sleep-induced surge in ATP and the decrease in P-AMPK levels set the stage for increased anabolic processes during sleep and provide insight into the molecular events leading to the restorative biosynthetic processes occurring during sleep.

  15. Thermodynamic phase transition in the rainbow Schwarzschild black hole

    SciTech Connect

    Gim, Yongwan; Kim, Wontae E-mail: wtkim@sogang.ac.kr

    2014-10-01

    We study the thermodynamic phase transition in the rainbow Schwarzschild black hole where the metric depends on the energy of the test particle. Identifying the black hole temperature with the energy from the modified dispersion relation, we obtain the modified entropy and thermodynamic energy along with the modified local temperature in the cavity to provide well defined black hole states. It is found that apart from the conventional critical temperature related to Hawking-Page phase transition there appears an additional critical temperature which is of relevance to the existence of a locally stable tiny black hole; however, the off-shell free energy tells us that this black hole should eventually tunnel into the stable large black hole. Finally, we discuss the reason why the temperature near the horizon is finite in the rainbow black hole by employing the running gravitational coupling constant, whereas it is divergent near the horizon in the ordinary Schwarzschild black hole.

  16. Analytic energy-level densities of separable harmonic oscillators including approximate hindered rotor corrections

    NASA Astrophysics Data System (ADS)

    Döntgen, M.

    2016-09-01

    Energy-level densities are key for obtaining various chemical properties. In chemical kinetics, energy-level densities are used to predict thermochemistry and microscopic reaction rates. Here, an analytic energy-level density formulation is derived using inverse Laplace transformation of harmonic oscillator partition functions. Anharmonic contributions to the energy-level density are considered approximately using a literature model for the transition from harmonic to free motions. The present analytic energy-level density formulation for rigid rotor-harmonic oscillator systems is validated against the well-studied CO+O˙ H system. The approximate hindered rotor energy-level density corrections are validated against the well-studied H2O2 system. The presented analytic energy-level density formulation gives a basis for developing novel numerical simulation schemes for chemical processes.

  17. Deburring small intersecting holes

    SciTech Connect

    Gillespie, L.K.

    1980-08-01

    Deburring intersecting holes is one of the most difficult deburring tasks faced by many industries. Only 14 of the 37 major deburring processes are applicable to most intersecting hole applications. Only five of these are normally applicable to small or miniature holes. Basic process capabilities and techniques used as a function of hole sizes and intersection depths are summarized.

  18. Hole-Aligning Tool

    NASA Technical Reports Server (NTRS)

    Collins, Frank A.; Saude, Frank; Sep, Martin J.

    1996-01-01

    Tool designed for use in aligning holes in plates or other structural members to be joined by bolt through holes. Holes aligned without exerting forces perpendicular to planes of holes. Tool features screw-driven-wedge design similar to (but simpler than) that of some automotive exhaust-pipe-expanding tools.

  19. Dialkylthio Substitution: An Effective Method to Modulate the Molecular Energy Levels of 2D-BDT Photovoltaic Polymers.

    PubMed

    Yao, Huifeng; Zhang, Hao; Ye, Long; Zhao, Wenchao; Zhang, Shaoqing; Hou, Jianhui

    2016-02-17

    Dialkylthio-substituted thienyl-benzodithiophene (BDT-DST) was designed and synthesized as a building block to modulate the molecular levels of the conjugated polymers, and three copolymers named PDST-BDD, PDST-TT and PDST-DPP were prepared and applied in polymer solar cells (PSCs). Theoretical calculations and electrochemical cyclic voltammetry (CV) measurement suggested that the dialkylthio group could decrease the molecular energy levels of the resulting polymers distinctly. The open-circuit voltage (VOC) of PSC devices based on PDST-BDD, PDST-TT, and PDST-DPP are as high as 1.0, 0.98, and 0.88 V, respectively, which are ∼0.15 V higher than those of the corresponding alky-substituted analogues. Moreover, the influence of the dialkylthio group on the absorption spectra, crystalline properties, hole mobilities, and blend morphologies of the polymers was also investigated. The results indicate that the dialkythio substitution is an effective method to modulate the molecular energy levels and that the BDT-DST unit has potential for constructing high-efficiency photovoltaic polymers.

  20. Bore hole navigator

    SciTech Connect

    Hoffman, G.J.

    1987-09-29

    A bore hole navigator is described comprising a two axis platform for lowering down a bore hole on a cable with its longitudinal axis parallel to the local bore hole direction. The two axis platform has an outer gimbal, bearing supported on the outer gimbal axis for rotation about the longitudinal axis of the platform, and an inner gimbal axis orthogonal the the outer gimbal axis. The inner gimbal axis has multiple axis segments spaced along the longitudinal axis of the platform and each bearing supported on the outer gimbal. The inner gimbal axis segment has a two axis gyro mounted thereon with its spin axis orthogonal to the respective inner gimbal axis segment, a first gyro sensitive axis parallel to the respective inner gimbal axis segment and a second gyro sensitive axis orthogonal to the spin axis. The second inner gimbal axis segment has a pitch torquer thereon operative to provide a controllable torque about the respective inner gimbal axis segment. The third inner gimbal axis segment has a pitch resolver thereon operative to measure rotation of the respective inner gimbal axis segment with respect to the outer gimbal. The first, second and third inner gimbal axis segments are coupled to rotate together. The outer gimbal has a yaw torquer thereon to provide a controllable torque about the outer gimbal axis, and a yaw resolver thereon to measure rotation of the outer gimbal about the outer gimbal axis. The outer gimbal also has a single axis accelerometer therein having its sensitive axis orthogonal to the outer gimbal axis and the inner gimbal axis segments.

  1. Deep Hole in 'Clovis'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1

    At a rock called 'Clovis,' the rock abrasion tool on NASA's Mars Exploration Rover Spirit cut a 9-millimeter (0.35-inch) hole during the rover's 216th martian day, or sol (Aug. 11, 2004). The hole is the deepest drilled in a rock on Mars so far. This approximately true-color view was made from images taken by Spirit's panoramic camera on sol 226 (Aug. 21, 2004) at around 12:50 p.m. local true solar time -- early afternoon in Gusev Crater on Mars. To the right is a 'brush flower' of circles produced by scrubbing the surface of the rock with the abrasion tool's wire brush. Scientists used rover's Moessbauer spectrometer and alpha particle X-ray spectrometer to look for iron-bearing minerals and determine the elemental chemical composition of the rock. This composite combines images taken with the camera's 750-, 530-, and 430-nanometer filters. The grayish-blue hue in this image suggests that the interior of the rock contains iron minerals that are less oxidized than minerals on the surface. The diameter of the hole cut into the rock is 4.5 centimeters (1.8 inches).

    Data on the graph (Figure 1) from the alpha particle X-ray spectrometer instrument on the robotic arm of NASA's Mars Exploration Rover Spirit reveal the elemental chemistry of two rocks, 'Ebenezer' and 'Clovis,' (see PIA06914) in the 'Columbia Hills.' Scientists found, through comparison of the rocks' chemistry, that Ebenezer and Clovis have very different compositions from the rocks on the Gusev plains.

  2. Method and apparatus of assessing down-hole drilling conditions

    DOEpatents

    Hall, David R.; Pixton, David S.; Johnson, Monte L.; Bartholomew, David B.; Fox, Joe

    2007-04-24

    A method and apparatus for use in assessing down-hole drilling conditions are disclosed. The apparatus includes a drill string, a plurality of sensors, a computing device, and a down-hole network. The sensors are distributed along the length of the drill string and are capable of sensing localized down-hole conditions while drilling. The computing device is coupled to at least one sensor of the plurality of sensors. The data is transmitted from the sensors to the computing device over the down-hole network. The computing device analyzes data output by the sensors and representative of the sensed localized conditions to assess the down-hole drilling conditions. The method includes sensing localized drilling conditions at a plurality of points distributed along the length of a drill string during drilling operations; transmitting data representative of the sensed localized conditions to a predetermined location; and analyzing the transmitted data to assess the down-hole drilling conditions.

  3. Nonstationary analogue black holes

    NASA Astrophysics Data System (ADS)

    Eskin, Gregory

    2014-12-01

    We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model see Unruh (1981 Phys. Rev. Lett. 46 1351). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes. We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symmetric nonstationary metrics.

  4. No supermassive black hole in M33?

    PubMed

    Merritt, D; Ferrarese, L; Joseph, C L

    2001-08-10

    We observed the nucleus of M33, the third-brightest galaxy in the Local Group, with the Space Telescope Imaging Spectrograph at a resolution at least a factor of 10 higher than previously obtained. Rather than the steep rise expected within the radius of gravitational influence of a supermassive black hole, the random stellar velocities showed a decrease within a parsec of the center of the galaxy. The implied upper limit on the mass of the central black hole is only 3000 solar masses, about three orders of magnitude lower than the dynamically inferred mass of any other supermassive black hole. Detecting black holes of only a few thousand solar masses is observationally challenging, but it is critical to establish how supermassive black holes relate to their host galaxies, and which mechanisms influence the formation and evolution of both. PMID:11463879

  5. Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes

    PubMed Central

    Petermann, Jana S.; Rohland, Anja; Sichardt, Nora; Lade, Peggy; Guidetti, Brenda; Weisser, Wolfgang W.; Gossner, Martin M.

    2016-01-01

    Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2°C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and

  6. Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes.

    PubMed

    Petermann, Jana S; Rohland, Anja; Sichardt, Nora; Lade, Peggy; Guidetti, Brenda; Weisser, Wolfgang W; Gossner, Martin M

    2016-01-01

    Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2°C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and

  7. Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes.

    PubMed

    Petermann, Jana S; Rohland, Anja; Sichardt, Nora; Lade, Peggy; Guidetti, Brenda; Weisser, Wolfgang W; Gossner, Martin M

    2016-01-01

    Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2°C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and

  8. Energy levels of isoelectronic impurities by large scale LDA calculations

    SciTech Connect

    Li, Jingbo; Wang, Lin-Wang

    2002-11-22

    Isoelectronic impurity states are localized states induced by stoichiometric single atom substitution in bulk semiconductor. Photoluminescence spectra indicate deep impurity levels of 0.5 to 0.9eV above the top of valence band for systems like: GaN:As, GaN:P, CdS:Te, ZnS:Te. Previous calculations based on small supercells seemingly confirmed these experimental results. However, the current ab initio calculations based on thousand atom supercells indicate that the impurity levels of the above systems are actually much shallower(0.04 to 0.23 eV), and these impurity levels should be compared with photoluminescence excitation spectra, not photoluminescence spectra.

  9. NASA Now: Black Holes

    NASA Video Gallery

    In this NASA Now episode, Dr. Daniel Patnaude talks about how his team discovered a baby black hole, why this is important and how black holes create tidal forces. Throughout his discussion, Patnau...

  10. Black hole entanglement and quantum error correction

    NASA Astrophysics Data System (ADS)

    Verlinde, Erik; Verlinde, Herman

    2013-10-01

    It was recently argued in [1] that black hole complementarity strains the basic rules of quantum information theory, such as monogamy of entanglement. Motivated by this argument, we develop a practical framework for describing black hole evaporation via unitary time evolution, based on a holographic perspective in which all black hole degrees of freedom live on the stretched horizon. We model the horizon as a unitary quantum system with finite entropy, and do not postulate that the horizon geometry is smooth. We then show that, with mild assumptions, one can reconstruct local effective field theory observables that probe the black hole interior, and relative to which the state near the horizon looks like a local Minkowski vacuum. The reconstruction makes use of the formalism of quantum error correcting codes, and works for black hole states whose entanglement entropy does not yet saturate the Bekenstein-Hawking bound. Our general framework clarifies the black hole final state proposal, and allows a quantitative study of the transition into the "firewall" regime of maximally mixed black hole states.

  11. Black holes without firewalls

    NASA Astrophysics Data System (ADS)

    Larjo, Klaus; Lowe, David A.; Thorlacius, Larus

    2013-05-01

    The postulates of black hole complementarity do not imply a firewall for infalling observers at a black hole horizon. The dynamics of the stretched horizon, that scrambles and reemits information, determines whether infalling observers experience anything out of the ordinary when entering a large black hole. In particular, there is no firewall if the stretched horizon degrees of freedom retain information for a time of the order of the black hole scrambling time.

  12. The Nearest Black Hole

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald (Technical Monitor); Garcia, Michael

    2005-01-01

    The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies.

  13. Key parameters of EUV resists for contact hole applications

    NASA Astrophysics Data System (ADS)

    Cho, Kyoungyong; Nakagawa, Hiroki; Maruyama, Ken; Shimizu, Makoto; Kimura, Tooru; Hishiro, Yoshi

    2012-03-01

    Patterning contact hole (CH) features with good critical dimension uniformity (CDU) is one of the most critical challenges for 10nm node lithography and beyond. Extreme ultraviolet lithography (EUVL) is considered a potential candidate because of its better aerial imaging and larger k1 factor than ArF immersion. To apply EUV lithography to high volume manufacturing, EUV resists must overcome both the trade-off among resolution (R), local CD uniformity (LCDU), and sensitivity (S) at CH features and the RLS trade-off at line/space (LS) features. We evaluated various resist materials for CH patterning applications using the microexposure tools (METs) at SEMATECH in Albany, NY, and at Lawrence Berkeley National Laboratory. In this study, we report the correlation between the lithographic performance of EUV resist at CH features and physical properties of chemically amplified resists (CARs) such as their dissolution behavior, the activation energy level of the protective group, and the acidity/acid diffusion length of the photoacid generator (PAG).

  14. Energy Levels and the de Broglie Relationship for High School Students

    ERIC Educational Resources Information Center

    Gianino, Concetto

    2008-01-01

    In this article, four examples of possible lessons on energy levels for high school are described: a particle in a box, a finite square well, the hydrogen atom and a harmonic oscillator. The energy levels are deduced through the use of the steady-state condition and the de Broglie relationship. In particular, the harmonic oscillator energy levels…

  15. Black Hole Battery

    NASA Astrophysics Data System (ADS)

    Levin, Janna; D'Orazio, Daniel

    2016-03-01

    Black holes are dark dead stars. Neutron stars are giant magnets. As the neutron star orbits the black hole, an electronic circuit forms that generates a blast of power just before the black hole absorbs the neutron star whole. The black hole battery conceivably would be observable at cosmological distances. Possible channels for luminosity include synchro-curvature radiation, a blazing fireball, or even an unstable, short-lived black hole pulsar. As suggested by Mingarelli, Levin, and Lazio, some fraction of the battery power could also be reprocessed into coherent radio emission to populate a subclass of fast radio bursts.

  16. Searching for Black Holes

    NASA Technical Reports Server (NTRS)

    Garica, M.

    2001-01-01

    In 1995 we proposed to carry out ground-based observations in order to securely identify stellar mass black holes in our galaxy. This type 4 proposal under NASA's UV, Visible, and Gravitational Astrophysics program compliments NASA's space-based research by following up black hole candidates found and studied with space-based observatories, in order to determine if they are indeed black holes. While our primary goal is to securely identify black holes by measuring their masses, a secondary goal is identifying unique visible-range signatures for black holes.

  17. Ion holes in the hydrodynamic regime in ultracold neutral plasmas

    SciTech Connect

    McQuillen, P.; Castro, J.; Strickler, T.; Bradshaw, S. J.; Killian, T. C.

    2013-04-15

    We describe the creation of localized density perturbations, or ion holes, in an ultracold neutral plasma in the hydrodynamic regime, and show that the holes propagate at the local ion acoustic wave speed. We also observe the process of hole splitting, which results from the formation of a density depletion initially at rest in the plasma. One-dimensional, two-fluid hydrodynamic simulations describe the results well. Measurements of the ion velocity distribution also show the effects of the ion hole and confirm the hydrodynamic conditions in the plasma.

  18. Black hole accretion.

    PubMed

    Narayan, Ramesh; Quataert, Eliot

    2005-01-01

    Black holes are most often detected by the radiation produced when they gravitationally pull in surrounding gas, in a process called accretion. The efficiency with which the hot gas radiates its thermal energy strongly influences the geometry and dynamics of the accretion flow. Both radiatively efficient thin disks and radiatively inefficient thick disks are observed. When the accreting gas gets close to the central black hole, the radiation it produces becomes sensitive to the spin of the hole and the presence of an event horizon. Analysis of the luminosities and spectra of accreting black holes has yielded tantalizing evidence for both rotating holes and event horizons. Numerical simulations imply that the relativistic jets often seen from accreting black holes may be powered in part by the spin of the hole. PMID:15637269

  19. Treatment of Electronic Energy Level Transition and Ionization Following the Particle-Based Chemistry Model

    NASA Technical Reports Server (NTRS)

    Liechty, Derek S.; Lewis, Mark

    2010-01-01

    A new method of treating electronic energy level transitions as well as linking ionization to electronic energy levels is proposed following the particle-based chemistry model of Bird. Although the use of electronic energy levels and ionization reactions in DSMC are not new ideas, the current method of selecting what level to transition to, how to reproduce transition rates, and the linking of the electronic energy levels to ionization are, to the author s knowledge, novel concepts. The resulting equilibrium temperatures are shown to remain constant, and the electronic energy level distributions are shown to reproduce the Boltzmann distribution. The electronic energy level transition rates and ionization rates due to electron impacts are shown to reproduce theoretical and measured rates. The rates due to heavy particle impacts, while not as favorable as the electron impact rates, compare favorably to values from the literature. Thus, these new extensions to the particle-based chemistry model of Bird provide an accurate method for predicting electronic energy level transition and ionization rates in gases.

  20. Information retrieval from black holes

    NASA Astrophysics Data System (ADS)

    Lochan, Kinjalk; Chakraborty, Sumanta; Padmanabhan, T.

    2016-08-01

    It is generally believed that, when matter collapses to form a black hole, the complete information about the initial state of the matter cannot be retrieved by future asymptotic observers, through local measurements. This is contrary to the expectation from a unitary evolution in quantum theory and leads to (a version of) the black hole information paradox. Classically, nothing else, apart from mass, charge, and angular momentum is expected to be revealed to such asymptotic observers after the formation of a black hole. Semiclassically, black holes evaporate after their formation through the Hawking radiation. The dominant part of the radiation is expected to be thermal and hence one cannot know anything about the initial data from the resultant radiation. However, there can be sources of distortions which make the radiation nonthermal. Although the distortions are not strong enough to make the evolution unitary, these distortions carry some part of information regarding the in-state. In this work, we show how one can decipher the information about the in-state of the field from these distortions. We show that the distortions of a particular kind—which we call nonvacuum distortions—can be used to fully reconstruct the initial data. The asymptotic observer can do this operationally by measuring certain well-defined observables of the quantum field at late times. We demonstrate that a general class of in-states encode all their information content in the correlation of late time out-going modes. Further, using a 1 +1 dimensional dilatonic black hole model to accommodate backreaction self-consistently, we show that observers can also infer and track the information content about the initial data, during the course of evaporation, unambiguously. Implications of such information extraction are discussed.

  1. Effective theory of black holes in the 1/D expansion

    NASA Astrophysics Data System (ADS)

    Emparan, Roberto; Shiromizu, Tetsuya; Suzuki, Ryotaku; Tanabe, Kentaro; Tanaka, Takahiro

    2015-06-01

    The gravitational field of a black hole is strongly localized near its horizon when the number of dimensions D is very large. In this limit, we can effectively replace the black hole with a surface in a background geometry (e.g. Minkowski or Anti-deSitter space). The Einstein equations determine the effective equations that this `black hole surface' (or membrane) must satisfy. We obtain them up to next-to-leading order in 1/ D for static black holes of the Einstein-(A)dS theory. To leading order, and also to next order in Minkowski backgrounds, the equations of the effective theory are the same as soap-film equations, possibly up to a redshift factor. In particular, the Schwarzschild black hole is recovered as a spherical soap bubble. Less trivially, we find solutions for `black droplets', i.e. black holes localized at the boundary of AdS, and for non-uniform black strings.

  2. Magnetic holes in the solar wind

    NASA Technical Reports Server (NTRS)

    Turner, J. M.; Burlaga, L. F.; Ness, N. F.; Lemaire, J. F.

    1977-01-01

    An analysis of high-resolution magnetic field measurements from the Goddard Space Flight Center magnetometer on Explorer 43 showed that low magnetic field intensities (less than 1 gamma) in the solar wind at 1 AU occur as distinct depressions, or 'holes', in otherwise nearly average conditions. These magnetic holes are new kinetic scale phenomena, having a characteristic dimension of the order of 20,000 km. They occurred at a rate of 1.5/d in the 18-day interval (March 18 to April 6, 1971) that was considered. Most magnetic holes are characterized by both a depression in /B/ and a change in the magnetic field direction, and some of these are possibly the result of magnetic merging. However, in other cases the direction, does not change; such holes are not due to merging but might be a diamagnetic effect due to localized plasma inhomogeneities.

  3. CPT-hole closure

    USGS Publications Warehouse

    Noce, T.E.; Holzer, T.L.

    2003-01-01

    The long-term stability of deep holes 1.75 inches. (4.4 cm) in diameter by 98.4 feet (30 m) created by cone penetration testing (CPT) was monitored at a site in California underlain by Holocene and Pleistocene age alluvial fan deposits. Portions of the holes remained open both below and above the 28.6-foot (8.7 m)-deep water table for approximately three years, when the experiment was terminated. Hole closure appears to be a very slow process that may take decades in the stiff soils studied here. Other experience suggests holes in softer soils may also remain open. Thus, despite their small diameter, CPT holes may remain open for years and provide paths for rapid migration of contaminants. The observations confirm the need to grout holes created by CPT soundings as well as other direct-push techniques in areas where protection of shallow ground water is important.

  4. Quantization of Black Holes

    NASA Astrophysics Data System (ADS)

    He, Xiao-Gang; Ma, Bo-Qiang

    We show that black holes can be quantized in an intuitive and elegant way with results in agreement with conventional knowledge of black holes by using Bohr's idea of quantizing the motion of an electron inside the atom in quantum mechanics. We find that properties of black holes can also be derived from an ansatz of quantized entropy Δ S = 4π k Δ R/{{-{λ }}}, which was suggested in a previous work to unify the black hole entropy formula and Verlinde's conjecture to explain gravity as an entropic force. Such an Ansatz also explains gravity as an entropic force from quantum effect. This suggests a way to unify gravity with quantum theory. Several interesting and surprising results of black holes are given from which we predict the existence of primordial black holes ranging from Planck scale both in size and energy to big ones in size but with low energy behaviors.

  5. Naked black holes

    SciTech Connect

    Horowitz, G.T.; Ross, S.F.

    1997-08-01

    It is shown that there are large static black holes for which all curvature invariants are small near the event horizon, yet any object which falls in experiences enormous tidal forces {ital outside} the horizon. These black holes are charged and near extremality, and exist in a wide class of theories including string theory. The implications for cosmic censorship and the black hole information puzzle are discussed. {copyright} {ital 1997} {ital The American Physical Society}

  6. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Molina, Mario J.

    1988-01-01

    Observations of Antarctic ozone levels and the discovery of a hole in the Antarctic region are examined. The effects of chlorofluorocarbons (CFCs) on the level of stratospheric ozone are analyzed. Three cycles explaining the cause of ozone depletion in the poles are proposed. A comparison of field data and proposed depletion cycles reveals that the chemical origin of the ozone hole is due to CFCs. The potential global effects of the Antarctic ozone hole are discussed.

  7. Energy level modification in lead sulfide quantum dot thin films through ligand exchange.

    PubMed

    Brown, Patrick R; Kim, Donghun; Lunt, Richard R; Zhao, Ni; Bawendi, Moungi G; Grossman, Jeffrey C; Bulović, Vladimir

    2014-06-24

    The electronic properties of colloidal quantum dots (QDs) are critically dependent on both QD size and surface chemistry. Modification of quantum confinement provides control of the QD bandgap, while ligand-induced surface dipoles present a hitherto underutilized means of control over the absolute energy levels of QDs within electronic devices. Here, we show that the energy levels of lead sulfide QDs, measured by ultraviolet photoelectron spectroscopy, shift by up to 0.9 eV between different chemical ligand treatments. The directions of these energy shifts match the results of atomistic density functional theory simulations and scale with the ligand dipole moment. Trends in the performance of photovoltaic devices employing ligand-modified QD films are consistent with the measured energy level shifts. These results identify surface-chemistry-mediated energy level shifts as a means of predictably controlling the electronic properties of colloidal QD films and as a versatile adjustable parameter in the performance optimization of QD optoelectronic devices.

  8. Open-hole fishing

    SciTech Connect

    Pietrobono, J.T.

    1988-01-01

    This paper reports on losing equipment in the hole that is one of the most expensive and potentially dangerous things that can go wrong in drilling a well. Drilling must come to a halt until the equipment is recovered, or the hole must be sidetracked. The well also can become hard to control with essential tools out of reach, increasing the risk of a blowout. Fishing, or recovering lost or stuck equipment in the hole, is therefore a critical procedure at any drilling operation. Fishing can be divided into two broad categories: open hole and cased hole. a major difference between the two is timing: open-hole fishing is done as the well is being drilled, whereas cased-hole fishing is performed during production or well workover. Fishing techniques and types of equipment used also vary between the tow. This lesson describes some of the basic techniques and tools used in open-hole fishing-that is, retrieving fish from a hole that is being drilled but is not yet cased.

  9. ENERGY LEVELS AND SPECTRAL LINES OF SINGLY IONIZED MANGANESE (Mn II)

    SciTech Connect

    Kramida, Alexander; Sansonetti, Jean E.

    2013-04-01

    This compilation revises the previously recommended list of energy levels of singly ionized manganese (Mn II) and provides a comprehensive list of observed spectral lines and transition probabilities in this spectrum. The new level optimization takes into account critically assessed uncertainties of measured wavelengths and includes about a hundred high-precision wavelengths determined by laser spectroscopy and Fourier transform techniques. Uncertainties of 63% of energy levels and 74% of Ritz wavelengths are reduced by a factor of three on average.

  10. New energy levels of atomic niobium by laser induced fluorescence spectroscopy in the near infrared

    NASA Astrophysics Data System (ADS)

    Öztürk, I. K.; Başar, Gö; Er, A.; Güzelçimen, F.; Başar, Gü; Kröger, S.

    2015-01-01

    Laser-induced fluorescence spectroscopy was applied in order to find new energy levels of the niobium atom. A continuous wave tuneable titanium-sapphire laser in the wavelength range from 750 to 865 nm and a hollow-cathode lamp were used. We discovered four energy levels of even parity, three lying levels below 19 000 cm-1 and one at much higher energy. Additionally hyperfine structure data of six levels of odd parity were determined.

  11. Sequence of hole resonances in complex oxide heterostructures.

    PubMed

    Smadici, S; Logvenov, G; Bozovic, I; Abbamonte, P

    2014-04-16

    Resonant soft x-ray scattering measurements at the O K edge on Sr2CuO4-ν/La2NiO4+δ (SCO/LNO) complex oxide superlattices show resonances for holes in the two constituent layers, in a sequence of energy levels. The observation of well defined resonances, on a superlattice with layers one unit cell thick, indicates that the resonance energy is largely unaffected by atoms outside a cluster extending half a unit cell along the c axis, consistent with calculations for bulk materials. Comparison to measurements on related superlattices confirms that the order of resonances at the O K edge reflects the order of hole ground-state energies in the heterostructure buried layers. For the SCO/LNO superlattices, the measurements show that the ground-state energies remain different in very thin SCO and LNO layers, which is a contributing factor when considering electronic reconstruction at interfaces, in addition to the areal density of ionic charges in the atomic planes. Different hole energy levels in the SCO/LNO superlattice also imply that holes do not spread into SCO from LNO layers. PMID:24675566

  12. Soft Hair on Black Holes.

    PubMed

    Hawking, Stephen W; Perry, Malcolm J; Strominger, Andrew

    2016-06-10

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  13. Soft Hair on Black Holes.

    PubMed

    Hawking, Stephen W; Perry, Malcolm J; Strominger, Andrew

    2016-06-10

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units. PMID:27341223

  14. Accretion disks around black holes

    NASA Technical Reports Server (NTRS)

    Abramowicz, M. A.

    1994-01-01

    The physics of accretion flow very close to a black hole is dominated by several general relativistic effects. It cannot be described by the standard Shakura Sunyaev model or by its relativistic version developed by Novikov and Thome. The most important of these effects is a dynamical mass loss from the inner edge of the disk (Roche lobe overflow). The relativistic Roche lobe overflow induces a strong advective cooling, which is sufficient to stabilize local, axially symmetric thermal and viscous modes. It also stabilizes the non-axially-symmetric global modes discovered by Papaloizou and Pringle. The Roche lobe overflow, however, destabilizes sufficiently self-gravitating accretion disks with respect to a catastrophic runaway of mass due to minute changes of the gravitational field induced by the changes in the mass and angular momentum of the central black hole. One of the two acoustic modes may become trapped near the inner edge of the disk. All these effects, absent in the standard model, have dramatic implications for time-dependent behavior of the accretion disks around black holes.

  15. Soft Hair on Black Holes

    NASA Astrophysics Data System (ADS)

    Hawking, Stephen W.; Perry, Malcolm J.; Strominger, Andrew

    2016-06-01

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  16. Newborn Black Holes

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  17. Can we track holes?

    PubMed Central

    Horowitz, Todd S.; Kuzmova, Yoana

    2011-01-01

    The evidence is mixed as to whether the visual system treats objects and holes differently. We used a multiple object tracking task to test the hypothesis that figural objects are easier to track than holes. Observers tracked four of eight items (holes or objects). We used an adaptive algorithm to estimate the speed allowing 75% tracking accuracy. In Experiments 1–5, the distinction between holes and figures was accomplished by pictorial cues, while red-cyan anaglyphs were used to provide the illusion of depth in Experiment 6. We variously used Gaussian pixel noise, photographic scenes, or synthetic textures as backgrounds. Tracking was more difficult when a complex background was visible, as opposed to a blank background. Tracking was easier when disks carried fixed, unique markings. When these factors were controlled for, tracking holes was no more difficult than tracking figures, suggesting that they are equivalent stimuli for tracking purposes. PMID:21334361

  18. Oxidative Chemical Vapor Deposition of Neutral Hole Transporting Polymer for Enhanced Solar Cell Efficiency and Lifetime.

    PubMed

    Jo, Won Jun; Nelson, Justin T; Chang, Sehoon; Bulović, Vladimir; Gradečak, Silvija; Strano, Michael S; Gleason, Karen K

    2016-08-01

    The concept of a neutral hole-transporting polymer is realized for the first time, by integrating patterned Cl(-) -doped poly(3,4-dimethoxythiophene) thin films into organic solar cells through a vacuum-based polymer vapor printing technique. Due to this novel polymer's neutrality, high transparency, good conductivity, and appropriate energy levels, the solar-cell efficiency and lifetime are significantly enhanced.

  19. Excluding black hole firewalls with extreme cosmic censorship

    SciTech Connect

    Page, Don N.

    2014-06-01

    The AMPS argument for black hole firewalls seems to arise not only from the assumption of local effective field theory outside the stretched horizon but also from an overcounting of internal black hole states that include states that are singular in the past. Here I propose to exclude such singular states by Extreme Cosmic Censorship (the conjectured principle that the universe is entirely nonsingular, except for transient singularities inside black and/or white holes). I argue that the remaining set of nonsingular realistic states do not have firewalls but yet preserve information in Hawking radiation from black holes that form from nonsingular initial states.

  20. Hole-ness of point clouds

    NASA Astrophysics Data System (ADS)

    Gronz, Oliver; Seeger, Manuel; Klaes, Björn; Casper, Markus C.; Ries, Johannes B.

    2015-04-01

    Accurate and dense 3D models of soil surfaces can be used in various ways: They can be used as initial shapes for erosion models. They can be used as benchmark shapes for erosion model outputs. They can be used to derive metrics, such as random roughness... One easy and low-cost method to produce these models is structure from motion (SfM). Using this method, two questions arise: Does the soil moisture, which changes the colour, albedo and reflectivity of the soil, influence the model quality? How can the model quality be evaluated? To answer these questions, a suitable data set has been produced: soil has been placed on a tray and areas with different roughness structures have been formed. For different moisture states - dry, medium, saturated - and two different lighting conditions - direct and indirect - sets of high-resolution images at the same camera positions have been taken. From the six image sets, 3D point clouds have been produced using VisualSfM. The visual inspection of the 3D models showed that all models have different areas, where holes of different sizes occur. But it is obviously a subjective task to determine the model's quality by visual inspection. One typical approach to evaluate model quality objectively is to estimate the point density on a regular, two-dimensional grid: the number of 3D points in each grid cell projected on a plane is calculated. This works well for surfaces that do not show vertical structures. Along vertical structures, many points will be projected on the same grid cell and thus the point density rather depends on the shape of the surface but less on the quality of the model. Another approach has been applied by using the points resulting from Poisson Surface Reconstructions. One of this algorithm's properties is the filling of holes: new points are interpolated inside the holes. Using the original 3D point cloud and the interpolated Poisson point set, two analyses have been performed: For all Poisson points, the

  1. Study of the crossing of quasi-energy levels in a four-level system

    SciTech Connect

    Arushanyan, S; Melikyan, A; Saakyan, S

    2011-05-31

    It was shown previously that in taking into account only dipole transitions, the crossing of quasi-energy levels is possible in the system if any of the transitions forms a closed loop. It followed herefrom that for the analysis of the crossing conditions, it is necessary to consider a system which has at least four levels. In this paper we show that we can uniquely specify which quasi-energy levels cross at the given values of the parameters of the atomic system and radiation field, without solving an algebraic quartic equation. It was found that the most suitable system for the implementation of the crossing is the group of energy levels {sup 5}S{sub 1/2}, {sup 5}P{sub 1/2}, {sup 5}P{sub 3/2} and {sup 5}D{sub 3/2} of a rubidium atom. The performed calculations of the laser field intensity and frequency values at which crossing takes place in this system show that they are easily attainable. It turned out that in this system there occur crossing of quasi-energy levels corresponding to the excited atomic levels. (intersection of quasi-energy levels)

  2. Energy levels of one-dimensional systems satisfying the minimal length uncertainty relation

    NASA Astrophysics Data System (ADS)

    Bernardo, Reginald Christian S.; Esguerra, Jose Perico H.

    2016-10-01

    The standard approach to calculating the energy levels for quantum systems satisfying the minimal length uncertainty relation is to solve an eigenvalue problem involving a fourth- or higher-order differential equation in quasiposition space. It is shown that the problem can be reformulated so that the energy levels of these systems can be obtained by solving only a second-order quasiposition eigenvalue equation. Through this formulation the energy levels are calculated for the following potentials: particle in a box, harmonic oscillator, Pöschl-Teller well, Gaussian well, and double-Gaussian well. For the particle in a box, the second-order quasiposition eigenvalue equation is a second-order differential equation with constant coefficients. For the harmonic oscillator, Pöschl-Teller well, Gaussian well, and double-Gaussian well, a method that involves using Wronskians has been used to solve the second-order quasiposition eigenvalue equation. It is observed for all of these quantum systems that the introduction of a nonzero minimal length uncertainty induces a positive shift in the energy levels. It is shown that the calculation of energy levels in systems satisfying the minimal length uncertainty relation is not limited to a small number of problems like particle in a box and the harmonic oscillator but can be extended to a wider class of problems involving potentials such as the Pöschl-Teller and Gaussian wells.

  3. Comparison of Open-Hole Compression Strength and Compression After Impact Strength on Carbon Fiber/Epoxy Laminates for the Ares I Composite Interstage

    NASA Technical Reports Server (NTRS)

    Hodge, Andrew J.; Nettles, Alan T.; Jackson, Justin R.

    2011-01-01

    Notched (open hole) composite laminates were tested in compression. The effect on strength of various sizes of through holes was examined. Results were compared to the average stress criterion model. Additionally, laminated sandwich structures were damaged from low-velocity impact with various impact energy levels and different impactor geometries. The compression strength relative to damage size was compared to the notched compression result strength. Open-hole compression strength was found to provide a reasonable bound on compression after impact.

  4. Black holes and beyond

    NASA Astrophysics Data System (ADS)

    Mathur, Samir D.

    2012-11-01

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole.

  5. ULTRAMASSIVE BLACK HOLE COALESCENCE

    SciTech Connect

    Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter E-mail: k.holley@vanderbilt.edu

    2015-01-10

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production.

  6. Antarctic Ozone Hole, 2000

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Each spring the ozone layer over Antarctica nearly disappears, forming a 'hole' over the entire continent. The hole is created by the interaction of some man-made chemicals-freon, for example-with Antarctica's unique weather patterns and extremely cold temperatures. Ozone in the stratosphere absorbs ultraviolet radiation from the sun, thereby protecting living things. Since the ozone hole was discovered many of the chemicals that destroy ozone have been banned, but they will remain in the atmosphere for decades. In 2000, the ozone hole grew quicker than usual and exceptionally large. By the first week in September the hole was the largest ever-11.4 million square miles. The top image shows the average total column ozone values over Antarctica for September 2000. (Total column ozone is the amount of ozone from the ground to the top of the atmosphere. A relatively typical measurement of 300 Dobson Units is equivalent to a layer of ozone 0.12 inches thick on the Earth's surface. Levels below 220 Dobson Units are considered to be significant ozone depletion.) The record-breaking hole is likely the result of lower than average ozone levels during the Antarctic fall and winter, and exceptionally cold temperatures. In October, however (bottom image), the hole shrank dramatically, much more quickly than usual. By the end of October, the hole was only one-third of it's previous size. In a typical year, the ozone hole does not collapse until the end of November. NASA scientists were surprised by this early shrinking and speculate it is related to the region's weather. Global ozone levels are measured by the Total Ozone Mapping Spectrometer (TOMS). For more information about ozone, read the Earth Observatory's ozone fact sheet, view global ozone data and see these ozone images. Images by Greg Shirah, NASA GSFC Scientific Visualization Studio.

  7. Impact behaviour of Napier/polyester composites under different energy levels

    NASA Astrophysics Data System (ADS)

    Fahmi, I.; Majid, M. S. Abdul; Afendi, M.; Haslan, M.; Helmi E., A.; M. Haameem J., A.

    2016-07-01

    The effects of different energy levels on the impact behaviour of Napier fibre/polyester reinforced composites were investigated. Napier fibre was extracted using traditional water retting process to be utilized as reinforcing materials in polyester composite laminates. 25% fibre loading composite laminates were prepared and impacted at three different energy levels; 2.5,5 and 7.5 J using an instrumented drop weight impact testing machine (IMATEK IM10). The outcomes show that peak force and contact time increase with increased impact load. The energy absorption was then calculated from the force displacement curve. The results indicated that the energy absorption decreases with increasing energy levels of the impact. Impacted specimens were observed visually for fragmentation fracture using an optical camera to identify the failure mechanisms. Fracture fragmentation pattern from permanent dent to perforation with radial and circumferential was observed.

  8. Chemical control over the energy-level alignment in a two-terminal junction

    NASA Astrophysics Data System (ADS)

    Yuan, Li; Franco, Carlos; Crivillers, Núria; Mas-Torrent, Marta; Cao, Liang; Sangeeth, C. S. Suchand; Rovira, Concepció; Veciana, Jaume; Nijhuis, Christian A.

    2016-07-01

    The energy-level alignment of molecular transistors can be controlled by external gating to move molecular orbitals with respect to the Fermi levels of the source and drain electrodes. Two-terminal molecular tunnelling junctions, however, lack a gate electrode and suffer from Fermi-level pinning, making it difficult to control the energy-level alignment of the system. Here we report an enhancement of 2 orders of magnitude of the tunnelling current in a two-terminal junction via chemical molecular orbital control, changing chemically the molecular component between a stable radical and its non-radical form without altering the supramolecular structure of the junction. Our findings demonstrate that the energy-level alignment in self-assembled monolayer-based junctions can be regulated by purely chemical modifications, which seems an attractive alternative to control the electrical properties of two-terminal junctions.

  9. Chemical control over the energy-level alignment in a two-terminal junction.

    PubMed

    Yuan, Li; Franco, Carlos; Crivillers, Núria; Mas-Torrent, Marta; Cao, Liang; Sangeeth, C S Suchand; Rovira, Concepció; Veciana, Jaume; Nijhuis, Christian A

    2016-07-26

    The energy-level alignment of molecular transistors can be controlled by external gating to move molecular orbitals with respect to the Fermi levels of the source and drain electrodes. Two-terminal molecular tunnelling junctions, however, lack a gate electrode and suffer from Fermi-level pinning, making it difficult to control the energy-level alignment of the system. Here we report an enhancement of 2 orders of magnitude of the tunnelling current in a two-terminal junction via chemical molecular orbital control, changing chemically the molecular component between a stable radical and its non-radical form without altering the supramolecular structure of the junction. Our findings demonstrate that the energy-level alignment in self-assembled monolayer-based junctions can be regulated by purely chemical modifications, which seems an attractive alternative to control the electrical properties of two-terminal junctions.

  10. Chemical control over the energy-level alignment in a two-terminal junction.

    PubMed

    Yuan, Li; Franco, Carlos; Crivillers, Núria; Mas-Torrent, Marta; Cao, Liang; Sangeeth, C S Suchand; Rovira, Concepció; Veciana, Jaume; Nijhuis, Christian A

    2016-01-01

    The energy-level alignment of molecular transistors can be controlled by external gating to move molecular orbitals with respect to the Fermi levels of the source and drain electrodes. Two-terminal molecular tunnelling junctions, however, lack a gate electrode and suffer from Fermi-level pinning, making it difficult to control the energy-level alignment of the system. Here we report an enhancement of 2 orders of magnitude of the tunnelling current in a two-terminal junction via chemical molecular orbital control, changing chemically the molecular component between a stable radical and its non-radical form without altering the supramolecular structure of the junction. Our findings demonstrate that the energy-level alignment in self-assembled monolayer-based junctions can be regulated by purely chemical modifications, which seems an attractive alternative to control the electrical properties of two-terminal junctions. PMID:27456200

  11. Chemical control over the energy-level alignment in a two-terminal junction

    PubMed Central

    Yuan, Li; Franco, Carlos; Crivillers, Núria; Mas-Torrent, Marta; Cao, Liang; Sangeeth, C. S. Suchand; Rovira, Concepció; Veciana, Jaume; Nijhuis, Christian A.

    2016-01-01

    The energy-level alignment of molecular transistors can be controlled by external gating to move molecular orbitals with respect to the Fermi levels of the source and drain electrodes. Two-terminal molecular tunnelling junctions, however, lack a gate electrode and suffer from Fermi-level pinning, making it difficult to control the energy-level alignment of the system. Here we report an enhancement of 2 orders of magnitude of the tunnelling current in a two-terminal junction via chemical molecular orbital control, changing chemically the molecular component between a stable radical and its non-radical form without altering the supramolecular structure of the junction. Our findings demonstrate that the energy-level alignment in self-assembled monolayer-based junctions can be regulated by purely chemical modifications, which seems an attractive alternative to control the electrical properties of two-terminal junctions. PMID:27456200

  12. Measuring Black Hole Spin

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    1999-09-01

    WE PROPOSE TO CARRY OUT A SYSTEMATIC STUDY OF EMISSION AND ABSORPTION SPECTRAL FEATURES THAT ARE OFTEN SEEN IN X-RAY SPECTRA OF BLACK HOLE BINARIES. THE EXCELLENT SENSITIVITY AND ENERGY RESOLUTION OF THE ACIS/HETG COMBINATION WILL NOT ONLY HELP RESOLVE AMBIGUITIES IN INTERPRETING THESE FEATURES, BUT MAY ALLOW MODELLING OF THE EMISSION LINE PROFILES IN DETAIL. THE PROFILES MAY CONTAIN INFORMATION ON SUCH FUNDAMENTAL PROPERTIES AS THE SPIN OF BLACK HOLES. THEREFORE, THIS STUDY COULD LEAD TO A MEASUREMENT OF BLACK HOLE SPIN FOR SELECTED SOURCES. THE RESULT CAN THEN BE DIRECTLY COMPARED WITH THOSE FROM PREVIOUS STUDIES BASED ON INDEPENDENT METHODS.

  13. Self stimulated particles generation by black holes

    NASA Astrophysics Data System (ADS)

    Gaina, Alex

    2005-10-01

    The Ideea of Black Holes Bomb was one of the most intriguing in the gravitational physics. Bohr was the first who quantized the levels of an atom. Subsequently his disciple J. A. Wheeler (1971) quantized the mass spin 0 and 1/2 levels near a black hole, described by a Schwarzschild metric. It is strange, but after this work the interest was drawn to Kerr black holes, due to discovery of particles generation by Ya. B. Zel'dovich and Ch. Misner in 1972. As a result, the ideea of a Black Holes bomb was announced by W.H. Press and S. Teukolsky in 1972. L.Ford (1975) observed, that test particles mass plays a role of a mirror, which could develope an instability. That ideea was independently discussed by Deruelle and Ruffini (1974) and Damour, Deruelle and Rufffini (1976), using WKB approach, while the analytic treatment of the bound levels problem in Kerr field for microscopically small black holes and mass particles was given by Ternov, Khalilov, Chizhov and Gaina (1978) and A. Vilenkin (1978) for a Kerr black hole inside a mirror. Once a particle could be localized on a bound level near a non-rotating (Schwarzschild ) black hole, due to stimulation, it will induces generation of another particles with the same quantum numbers (on the same level). This process will be a self-stimulated generation of particles, which was discussed in the literature by R. Wald and J. York, Jr. The accumulatiion of bosons on the bound levels, particularly on the s-bound level, will be exponentially fast for microscopically small black holes and will lead to a true instablity of Schwarzschild black holes. This is valid for bosons only, since the Fermi-Dirac statistics interdicts the accumulation of more than two particles with oposite spin. As a result the Black Holes mass will be limited M>= 8"pi"/5 x (M(pl))^2/m , where m is the scalar particles minimal rest mass, existing in nature, since the maximal growing rate for the instability is occuring for mM=8"pi"/5(M(pl))^2. If photon have a

  14. 230 s room-temperature storage time and 1.14 eV hole localization energy in In{sub 0.5}Ga{sub 0.5}As quantum dots on a GaAs interlayer in GaP with an AlP barrier

    SciTech Connect

    Bonato, Leo Sala, Elisa M.; Stracke, Gernot; Nowozin, Tobias; Strittmatter, André; Ajour, Mohammed Nasser; Daqrouq, Khaled; Bimberg, Dieter

    2015-01-26

    A GaP n{sup +}p-diode containing In{sub 0.5}Ga{sub 0.5}As quantum dots (QDs) and an AlP barrier is characterized electrically, together with two reference samples: a simple n{sup +}p-diode and an n{sup +}p-diode with AlP barrier. Localization energy, capture cross-section, and storage time for holes in the QDs are determined using deep-level transient spectroscopy. The localization energy is 1.14(±0.04) eV, yielding a storage time at room temperature of 230(±60) s, which marks an improvement of 2 orders of magnitude compared to the former record value in QDs. Alternative material systems are proposed for still higher localization energies and longer storage times.

  15. Energy levels of odd-even nuclei using broken pair model

    NASA Astrophysics Data System (ADS)

    Hamammu, I. M.; Haq, S.; Eldahomi, J. M.

    2012-09-01

    A method to calculate energy levels and wave functions of odd-even nuclei, in the frame work of the broken pair model have been developed. The accuracy of the model has been tested by comparing the shell model results of limiting cases in which the broken pair model exactly coincides with the shell model, where there are two-proton/neutron + one-neutron/proton in the valence levels. The model is then applied to calculate the energy levels of some nuclei in the Zirconium region. The model results compare reasonably well with the shell model as well as with the experimental data.

  16. Inclination Angles of Black Hole X-Ray Binaries Manifest Strong Gravity around Black Holes

    NASA Technical Reports Server (NTRS)

    Zhang, S. N.; Zhang, Xiao-Ling; Yao, Yangsen

    2002-01-01

    System inclination angles have been determined for about 15 X-ray binaries, in which stellar mass black holes are considered to exist. These inclination angles range between 25 degrees and 80 degrees, but peaked between 60-70 degrees. This peak is not explained in the frame work of Newtonian gravity. However, this peak is reproduced naturally if we model the observed X-ray radiations as being produced in the accretion disks very close to the black hole horizons, where the extremely strong general and special relativistic effects, caused by the extremely strong gravity near the black hole horizons, modify the local radiation significantly as the X-rays propagate to the remote observer. Therefore the peak of the inclination angle distribution provides evidence or strong gravity around stellar mass black holes.

  17. Rotating Black Holes and the Kerr Metric

    NASA Astrophysics Data System (ADS)

    Kerr, Roy Patrick

    2008-10-01

    Since it was first discovered in 1963 the Kerr metric has been used by relativists as a test-bed for conjectures on worm-holes, time travel, closed time-like loops, and the existence or otherwise of global Cauchy surfaces. More importantly, it has also used by astrophysicists to investigate the effects of collapsed objects on their local environments. These two groups of applications should not be confused. Astrophysical Black Holes are not the same as the Kruskal solution and its generalisations.

  18. Black hole entropy and isolated horizons thermodynamics.

    PubMed

    Ghosh, Amit; Perez, Alejandro

    2011-12-01

    We present a statistical mechanical calculation of the thermodynamical properties of (nonrotating) isolated horizons. The introduction of the Planck scale allows for the definition of a universal horizon temperature (independent of the mass of the black hole) and a well-defined notion of energy (as measured by suitable local observers) proportional to the horizon area in Planck units. The microcanonical and canonical ensembles associated with the system are introduced. Black hole entropy and other thermodynamical quantities can be consistently computed in both ensembles and results are in agreement with Hawking's semiclassical analysis for all values of the Immirzi parameter.

  19. Introducing the Black Hole

    ERIC Educational Resources Information Center

    Ruffini, Remo; Wheeler, John A.

    1971-01-01

    discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)

  20. Illuminating black holes

    NASA Astrophysics Data System (ADS)

    Barr, Ian A.; Bull, Anne; O’Brien, Eileen; Drillsma-Milgrom, Katy A.; Milgrom, Lionel R.

    2016-07-01

    Two-dimensional shadows formed by illuminating vortices are shown to be visually analogous to the gravitational action of black holes on light and surrounding matter. They could be useful teaching aids demonstrating some of the consequences of general relativity.

  1. Astrophysics: Monster black holes

    NASA Astrophysics Data System (ADS)

    Cappellari, Michele

    2011-12-01

    A combination of ground-based and spacecraft observations has uncovered two black holes of 10 billion solar masses in the nearby Universe. The finding sheds light on how these cosmic monsters co-evolve with galaxies.

  2. Helical superconducting black holes.

    PubMed

    Donos, Aristomenis; Gauntlett, Jerome P

    2012-05-25

    We construct novel static, asymptotically five-dimensional anti-de Sitter black hole solutions with Bianchi type-VII(0) symmetry that are holographically dual to superconducting phases in four spacetime dimensions with a helical p-wave order. We calculate the precise temperature dependence of the pitch of the helical order. At zero temperature the black holes have a vanishing entropy and approach domain wall solutions that reveal homogenous, nonisotropic dual ground states with an emergent scaling symmetry.

  3. Orthotropic hole element

    NASA Technical Reports Server (NTRS)

    Markham, J. W.; Smith, C. V.

    1983-01-01

    A finite element was developed to adequately represent the state of stress in the region around a circular hole in orthotropic material experiencing reasonably general loading. This has been achieved through a complementary virtual work formulation of the stiffness and stress matrices for a square element with a center circular hole. The element has been incorporated into COSMIC/NASTRAN as a dummy element. Sample problems have been solved and these results are presented.

  4. Black holes and beyond

    SciTech Connect

    Mathur, Samir D.

    2012-11-15

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole. - Highlights: Black-Right-Pointing-Pointer The information paradox is a serious problem. Black-Right-Pointing-Pointer To solve it we need to find 'hair' on black holes. Black-Right-Pointing-Pointer In string theory we find 'hair' by the fuzzball construction. Black-Right-Pointing-Pointer Fuzzballs help to resolve many other issues in gravity.

  5. Charged Galileon black holes

    SciTech Connect

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar E-mail: christos.charmousis@th.u-psud.fr

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  6. Braneworld Black Holes

    NASA Astrophysics Data System (ADS)

    Whisker, Richard

    2008-10-01

    In this thesis we investigate black holes in the Randall-Sundrum braneworld scenario. We begin with an overview of extra-dimensional physics, from the original proposal of Kaluza and Klein up to the modern braneworld picture of extra dimensions. A detailed description of braneworld gravity is given, with particular emphasis on its compatibility with experimental tests of gravity. We then move on to a discussion of static, spherically symmetric braneworld black hole solutions. Assuming an equation of state for the ``Weyl term'', which encodes the effects of the extra dimension, we are able to classify the general behaviour of these solutions. We then use the strong field limit approach to investigate the gravitational lensing properties of some candidate braneworld black hole solutions. It is found that braneworld black holes could have significantly different observational signatures to the Schwarzschild black hole of standard general relativity. Rotating braneworld black hole solutions are also discussed, and we attempt to generate rotating solutions from known static solutions using the Newman-Janis complexification ``trick''.

  7. Searching for Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, M.

    1998-01-01

    Our UV/VIS work concentrates on black hole X-ray nova. These objects consist of two stars in close orbit, one of which we believe is a black hole - our goal is to SHOW that one is a black hole. In order to reach this goal we carry out observations in the Optical, UV, IR and X-ray bands, and compare the observations to theoretical models. In the past year, our UV/VIS grant has provided partial support (mainly travel funds and page charges) for work we have done on X-ray nova containing black holes and neutron stars. We have been very successful in obtaining telescope time to support our project - we have completed approximately a dozen separate observing runs averaging 3 days each, using the MMT (5M), Lick 3M, KPNO 2.1M, CTIO 4M, CTIO 1.5M, and the SAO/WO 1.2M telescopes. These observations have allowed the identification of one new black hole (Nova Oph 1977), and allowed the mass of another to be measured (GS2000+25). Perhaps our most exciting new result is the evidence we have gathered for the existence of 'event horizons' in black hole X-ray nova.

  8. Inversion Vibrational Energy Levels of AsH3 + Studied by Zero-Kinetic Photoelectron Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mo, Yuxiang

    2016-06-01

    The rotational-resolved vibrational spectra of AsH3 + have been measured for the first time with vibrational energies up to 6000 wn above the ground state using zero-kinetic energy photoelectron spectroscopic method. The inversion vibrational energy levels (νb{2}) and the corresponding rotational constants for the νb{2} =0-16 have been determined. The tunneling splittings of the inversion vibration energy levels have been observed for the ground and the first excited vibrational states. The geometric parameters of AsH3 + as a function of inversion vibrational quantum states have been determined, indicating that the geometric structure of the cation changes from near planar structure to a pyramidal structure with more vibrational excitations. In addition to the experimental measurement, a two-dimensional theoretical calculation including the two symmetric vibrational modes was performed to determine the energy levels of the symmetric inversion and As-H stretching vibrations. The calculated vibrational energy levels are in good agreement with the experimental results. The first adiabatic ionization energy (IE) for AsH3 was also accurately determined. The result of this work will be compared with our published result on the PH3+.

  9. Self-energy shift of the energy levels of atomic hydrogen in photonic crystal medium

    NASA Astrophysics Data System (ADS)

    Gainutdinov, R. Kh; Khamadeev, M. A.; Steryakov, O. V.; Ziyatdinova, K. A.; Salakhov, M. Kh

    2016-05-01

    Corrections to the average kinetic energy of atomic electrons caused by the change in electron mass in the photonic crystal medium are investigated. Corresponding shift of energy levels of atoms placed in a photonic crystal is shown to be of order of the ordinary Lamb shift.

  10. Probing Energy Levels of Large Array Quantum Dot Superlattice by Electronic Transport Measurement

    NASA Astrophysics Data System (ADS)

    Bisri, S. Z.; Degoli, E.; Spallanzani, N.; Krishnan, G.; Kooi, B.; Ghica, C.; Yarema, M.; Protesescu, L.; Heiss, W.; Kovalenko, M.; Pulci, O.; Ossicini, S.; Iwasa, Y.; Loi, M. A.

    2015-03-01

    Colloidal quantum dot superlattice (CQDS) emerges as new type of hybrid solids allowing easy fabrication of devices that exploits the quantum confinement properties of individual QD. This materials displays peculiar characters, making investigation of their transport properties nontrivial. Besides the bandgap variations, 0D nature of QD lead to the formation of discrete energy subbands. These subbands are crucial for multiple exciton generation (for efficient solar cell), thermoelectric material and multistate transistor. Full understanding of the CQDS energy level structure is vital to use them in complex devices. Here we show a powerful method to determine the CQDS electronic energy levels from their intrinsic charge transport characteristics. Via the use of ambipolar transistors with CQDS as active materials and gated using highly capacitive ionic liquid gating, Fermi energy can be largely tuned. It can access energy levels beyond QD's HOMO & LUMO. Ability to probe not only the bandgap, but also the discrete energy level from large assembly of QD at room temperature suggests the formation of energy minibands in this system.

  11. Energy Levels in Helium and Neon Atoms by an Electron-Impact Method.

    ERIC Educational Resources Information Center

    Taylor, N.; And Others

    1981-01-01

    Electronic energy levels in noble gas atoms may be determined with a simple teaching apparatus incorporating a resonance potentials tube in which the electron beam intensity is held constant. The resulting spectra are little inferior to those obtained by more elaborate electron-impact methods and complement optical emission spectra. (Author/SK)

  12. Peculiarities of collisional excitation transfer with excited screened energy levels of atoms

    SciTech Connect

    Gerasimov, V. A.; Gerasimov, V. V.; Pavlinskiy, A. V.

    2007-09-15

    We report an experimental discovery of deviations from the known regularities in collisional excitation transfer processes for metal atoms. The collisional excitation transfer with excited screened energy levels of thulium and dysprosium atoms is studied. The selecting role of the screening 6s shell in collisional excitation transfer is shown.

  13. Resonating Behaviour of Nanomachined Holed Microcantilevers

    PubMed Central

    Canavese, Giancarlo; Ricci, Alessandro; Gazzadi, Gian Carlo; Ferrante, Ivan; Mura, Andrea; Marasso, Simone Luigi; Ricciardi, Carlo

    2015-01-01

    The nanofabrication of a nanomachined holed structure localized on the free end of a microcantilever is here presented, as a new tool to design micro-resonators with enhanced mass sensitivity. The proposed method allows both for the reduction of the sensor oscillating mass and the increment of the resonance frequency, without decreasing the active surface of the device. A theoretical analysis based on the Rayleigh method was developed to predict resonance frequency, effective mass, and effective stiffness of nanomachined holed microresonators. Analytical results were checked by Finite Element simulations, confirming an increase of the theoretical mass sensitivity up to 250%, without altering other figures of merit. The nanomachined holed resonators were vibrationally characterized, and their Q-factor resulted comparable with solid microcantilevers with same planar dimensions. PMID:26643936

  14. Resonating Behaviour of Nanomachined Holed Microcantilevers.

    PubMed

    Canavese, Giancarlo; Ricci, Alessandro; Gazzadi, Gian Carlo; Ferrante, Ivan; Mura, Andrea; Marasso, Simone Luigi; Ricciardi, Carlo

    2015-01-01

    The nanofabrication of a nanomachined holed structure localized on the free end of a microcantilever is here presented, as a new tool to design micro-resonators with enhanced mass sensitivity. The proposed method allows both for the reduction of the sensor oscillating mass and the increment of the resonance frequency, without decreasing the active surface of the device. A theoretical analysis based on the Rayleigh method was developed to predict resonance frequency, effective mass, and effective stiffness of nanomachined holed microresonators. Analytical results were checked by Finite Element simulations, confirming an increase of the theoretical mass sensitivity up to 250%, without altering other figures of merit. The nanomachined holed resonators were vibrationally characterized, and their Q-factor resulted comparable with solid microcantilevers with same planar dimensions. PMID:26643936

  15. Optical decoherence and energy level structure of 0.1%Tm3+:LiNbO3

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Thiel, C. W.; Cone, R. L.

    2012-04-01

    We report the energy level structure of the 3H6 and 3H4 multiplets for Tm3+ doped congruent LiNbO3, as well as the decoherence properties and their temperature dependencies for the 3H6(1)↔3H4(1a) transition at 794 nm. It is shown that this material provides very significant improvements in bandwidth, time-bandwidth product, and sensitivity for spatial-spectral holographic signal processing devices and quantum memories based on spectral hole burning. The available signal processing bandwidth for 0.1%Tm3+:LiNbO3 is 300 GHz versus 20 GHz for Tm3+YAG. The peak absorption coefficient for 0.1%Tm3+:LiNbO3 is 15 cm-1 at 794.5 nm compared with 1.7 cm-1 for 0.1%Tm:YAG at 793 nm, and the total absorption strength is eighty times stronger. The oscillator strength for Tm3+:LiNbO3 is about twenty-five times larger than that for Tm3+:YAG, making the material five times more sensitive for processing high-bandwidth analog signals. The homogeneous linewidth, which determines processing time or spectrum analyzer resolution, is 30 kHz at 1.6 K and 350 kHz at 6 K, as measured by photon echoes. Those values establish potential time-bandwidth products of 107 and 7 ×105, respectively. The temperature dependence of the homogeneous linewidth was explained by observation of a 7.8 cm-1 crystal field level in the ground multiplet and direct phonon coupling. The excited state 3H4 lifetime T1 is 152 μs and the bottleneck lifetime of the lowest 3F4 level is 7 ms from photon echo measurements. These factors combine to provide a surprisingly large increase in key parameters that determine material performance for spatial-spectral holography, quantum information, and other spectral hole burning applications.

  16. Asymmetric interiors for small black holes

    NASA Astrophysics Data System (ADS)

    Kabat, Daniel; Lifschytz, Gilad

    2016-08-01

    We develop the representation of infalling observers and bulk fields in the CFT as a way to understand the black hole interior in AdS. We first discuss properties of CFT states which are dual to black holes. We then show that in the presence of a Killing horizon bulk fields can be decomposed into pieces we call ingoing and outgoing. The ingoing field admits a simple operator representation in the CFT, even inside a small black hole at late times, which leads to a simple CFT description of infalling geodesics. This means classical infalling observers will experience the classical geometry in the interior. The outgoing piece of the field is more subtle. In an eternal two-sided geometry it can be represented as an operator on the left CFT. In a stable one-sided geometry it can be described using entanglement via the PR construction. But in an evaporating black hole trans-horizon entanglement breaks down at the Page time, which means that for old black holes the PR construction fails and the outgoing field does not see local geometry. This picture of the interior allows the CFT to reconcile unitary Hawking evaporation with the classical experience of infalling observers.

  17. Gravitational effects of rotating braneworld black holes

    SciTech Connect

    Aliev, Alikram N.; Talazan, Pamir

    2009-08-15

    We study the light deflection effect and the relativistic periastron and frame-dragging precessions for a rotating black hole localized on the brane in the Randall-Sundrum braneworld scenario. Focusing on a light ray, which passes through the field of the black hole in its equatorial plane, we first calculate the deflection angle in the weak field limit. We obtain an analytical formula, involving the related perturbative parameters of the field up to the second order. We then proceed with the numerical calculation of the deflection angle in the strong field limit when the light ray passes at the closest distance of approach to the limiting photon orbit. We show that the deflection angles for the light ray, winding maximally rotating Kerr and braneworld black holes in the same direction as their rotation, become essentially indistinguishable from each other for a specific value of the negative tidal charge. The same feature occurs in the relativistic precession frequencies at characteristic radii, for which the radial epicyclic frequency of the test particle motion attains its highest value. These results show that to distinguish between these two types of black holes one also needs to know the precise value of the angular momentum from independent observations, which for a maximally rotating braneworld black hole must exceed the Kerr bound in general relativity.

  18. Gravitational effects of rotating braneworld black holes

    NASA Astrophysics Data System (ADS)

    Aliev, Alikram N.; Talazan, Pamir

    2009-08-01

    We study the light deflection effect and the relativistic periastron and frame-dragging precessions for a rotating black hole localized on the brane in the Randall-Sundrum braneworld scenario. Focusing on a light ray, which passes through the field of the black hole in its equatorial plane, we first calculate the deflection angle in the weak field limit. We obtain an analytical formula, involving the related perturbative parameters of the field up to the second order. We then proceed with the numerical calculation of the deflection angle in the strong field limit when the light ray passes at the closest distance of approach to the limiting photon orbit. We show that the deflection angles for the light ray, winding maximally rotating Kerr and braneworld black holes in the same direction as their rotation, become essentially indistinguishable from each other for a specific value of the negative tidal charge. The same feature occurs in the relativistic precession frequencies at characteristic radii, for which the radial epicyclic frequency of the test particle motion attains its highest value. These results show that to distinguish between these two types of black holes one also needs to know the precise value of the angular momentum from independent observations, which for a maximally rotating braneworld black hole must exceed the Kerr bound in general relativity.

  19. Electron holes appear to trigger cancer-implicated mutations

    NASA Astrophysics Data System (ADS)

    Miller, John; Villagran, Martha

    Malignant tumors are caused by mutations, which also affect their subsequent growth and evolution. We use a novel approach, computational DNA hole spectroscopy [M.Y. Suarez-Villagran & J.H. Miller, Sci. Rep. 5, 13571 (2015)], to compute spectra of enhanced hole probability based on actual sequence data. A hole is a mobile site of positive charge created when an electron is removed, for example by radiation or contact with a mutagenic agent. Peaks in the hole spectrum depict sites where holes tend to localize and potentially trigger a base pair mismatch during replication. Our studies of reveal a correlation between hole spectrum peaks and spikes in human mutation frequencies. Importantly, we also find that hole peak positions that do not coincide with large variant frequencies often coincide with cancer-implicated mutations and/or (for coding DNA) encoded conserved amino acids. This enables combining hole spectra with variant data to identify critical base pairs and potential cancer `driver' mutations. Such integration of DNA hole and variance spectra could also prove invaluable for pinpointing critical regions, and sites of driver mutations, in the vast non-protein-coding genome. Supported by the State of Texas through the Texas Ctr. for Superconductivity.

  20. Black Hole Boldly Goes Where No Black Hole Has Gone Before

    NASA Astrophysics Data System (ADS)

    2007-01-01

    centres of galaxies. It is perhaps possible for a stellar-mass black hole to gain enough mass through merging with other stellar-mass black holes or accreting star gas to stay locked in a cluster. About 100 solar masses would do. Once entrenched, the black hole has the opportunity to merge with other black holes or accrete gas from a local neighbourhood rife with star-stuff. In this way, they could grow into IMBHs. "If a black hole is massive enough, there's a good chance it can survive the pressures of living in a globular cluster, since it will be too heavy to be kicked out," said Arunav Kundu of Michigan State University, a co-author on the Nature report. "That's what is intriguing about this discovery. We may be seeing how a black hole can grow considerably, become more entrenched in the cluster, and then grow some more. "On the other hand," continued Kundu, "there are a variety of ways to make ULXs without requiring intermediate mass black holes. In particular, if the light goes out in a different direction than the one from which the gas comes in, it doesn't put any force on the gas. Also, if the light can be 'focused' towards us by reflecting off the gas in the same way that light from a flashlight bulb bounces off the little mirror in the flashlight, making the object appear brighter than it really is." Ongoing work will help to determine whether this object is a stellar-mass black hole showing an unusual manner of sucking in gas, allowing it to be extra bright, or an IMBH. The team, which also includes Steve Zepf from Michigan State University, and Katherine Rhode from Wesleyan University, has data for thousands of other globular clusters, which they are now analyzing in an effort to determine just how common this phenomenon is. Note for editors The findings appear on line in the 4 January issue of the journal Nature, in the article titled: "A black hole in a globular cluster", by Thomas J. Maccarone, Arunav Kundu, Stephen E. Zepf and Katherine L. Rhode.

  1. The Role of Primordial Kicks on Black Hole Merger Rates

    NASA Astrophysics Data System (ADS)

    Micic, M.; Sigurdsson, S.; Abel, T.

    2005-12-01

    Primordial stars are likely to be very massive, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos. Such early black holes, could be the seed black holes for the many supermassive black holes found in galaxies in the local universe. If they exist, their mergers with nearby supermassive black holes may be a prime signal for long wavelength gravitational wave detectors. We simulate formation of black holes in the center of high redshift dark matter halos and explore implications of initial natal kick velocities conjectured by some formation models. The central concentration of early black holes in present day galaxies is reduced if they are born even with moderate kicks of tens of km/s. The modest kicks allow the black holes to leave their parent halo, which consequently leads to dynamical friction being less effective on the lower mass black holes as compared to those still embedded in their parent halos. Therefore, merger rates may be reduced by more than an order of magnitude. Using analytical and illustrative cosmological N body simulations we quantify the role of natal kicks of black holes formed from massive metal free stars on their merger rates with supermassive black holes in present day galaxies. Our results also apply to black holes ejected by the gravitational slingshot mechanism. We acknowledge the support of the Center for Gravitational Wave Physics funded by the NSF under cooperative agreement PHY 01-14375, NSF grants PHY 98-00973 and PHY 02-44788, the Zaccheus Daniel Fellowship, and the Eberly College of Science.

  2. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, John

    2009-01-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  3. Supermassive black hole ancestors

    NASA Astrophysics Data System (ADS)

    Petri, A.; Ferrara, A.; Salvaterra, R.

    2012-05-01

    In the attempt to alleviate the difficulties created by their early formation, we study a model in which supermassive black holes (SMBHs) can grow by the combined action of gas accretion on heavy seeds and mergers of both heavy ? and light ? seeds. The former results from the direct collapse of gas in ? K, H2-free haloes; the latter are the end product of a standard H2-based star formation process. The H2-free condition is attained by exposing haloes to a strong (J21≳ 103) Lyman-Werner ultraviolet (UV) background produced by both accreting BHs and stars, thus establishing a self-regulated growth regime. We find that this condition is met already at z˜ 18 in the highly biased regions in which quasars are born. The key parameter allowing the formation of SMBHs by z= 6-7 is the fraction of haloes that can form heavy seeds: the minimum requirement is that fheavy≳ 0.001; SMBH as large as 2 × 1010 M⊙ can be obtained when fheavy approaches unity. Independently of fheavy, the model produces a high-z stellar bulge-BH mass relation which is steeper than the local one, implying that SMBHs formed before their bulge was in place. The formation of heavy seeds, allowed by the Lyman-Werner radiative feedback in the quasar-forming environment, is crucial to achieve a fast growth of the SMBH by merger events in the early phases of its evolution, i.e. z≳ 7. The UV photon production is largely dominated by stars in galaxies, i.e. BH accretion radiation is subdominant. Interestingly, we find that the final mass of light BHs and of the SMBH in the quasar is roughly equal by z= 6; by the same time, only 19 per cent of the initial baryon content has been converted into stars. The SMBH growth is dominated at all epochs z > 7.2 by mergers (exceeding accretion by a factor of 2-50); at later times, accretion becomes by far the most important growth channel. We finally discuss possible shortcomings of the model.

  4. Interplanetary magnetic holes: Theory

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Lemaire, J. F.

    1978-01-01

    Magnetic holes in the interplanetary medium are explained as stationary, non-propagating, equilibrium structures in which there are field-aligned enhancements of the plasma density and/or temperature. Magnetic anti-holes are considered to be associated with depressions in the plasma pressure. In this model, the observed changes in the magnetic field intensity and direction are due to diamagnetic currents that are carried by ions which drift in a sheath as the result of gradients in the magnetic field and in the plasma pressure within the sheath. The thickness of the sheaths considered is approximately a few ion Larmor radii. An electric field is normal to the magnetic field in the sheath. Solutions of Vlasov's equation and Maxwell's equations are presented which account for several types of magnetic holes, including null-sheets, that were observed.

  5. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  6. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2010-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wove detection, testing general relativity, and astrophysics.

  7. Turbulent black holes.

    PubMed

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  8. Turbulent black holes.

    PubMed

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids. PMID:25768746

  9. Bringing Black Holes Home

    NASA Astrophysics Data System (ADS)

    Furmann, John M.

    2003-03-01

    Black holes are difficult to study because they emit no light. To overcome this obstacle, scientists are trying to recreate a black hole in the laboratory. The article gives an overview of the theories of Einstein and Hawking as they pertain to the construction of the Large Hadron Collider (LHC) near Geneva, Switzerland, scheduled for completion in 2006. The LHC will create two beams of protons traveling in opposing directions that will collide and create a plethora of scattered elementary particles. Protons traveling in opposite directions at very high velocities may create particles that come close enough to each other to feel their compacted higher dimensions and create a mega force of gravity that can create tiny laboratory-sized black holes for fractions of a second. The experiments carried out with LHC will be used to test modern string theory and relativity.

  10. Black-hole astrophysics

    SciTech Connect

    Bender, P.; Bloom, E.; Cominsky, L.

    1995-07-01

    Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

  11. Ozone Hole Over Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

  12. Janus black holes

    NASA Astrophysics Data System (ADS)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  13. Slowly balding black holes

    SciTech Connect

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-15

    The 'no-hair' theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively ''frozen in'' the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N{sub B}=e{Phi}{sub {infinity}}/({pi}c({h_bar}/2{pi})), where {Phi}{sub {infinity}}{approx_equal}2{pi}{sup 2}B{sub NS}R{sub NS}{sup 3}/(P{sub NS}c) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole's magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  14. Growth of Primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Harada, Tomohiro

    Primordial black holes have important observational implications through Hawking evaporation and gravitational radiation as well as being a candidate for cold dark matter. Those black holes are assumed to have formed in the early universe typically with the mass scale contained within the Hubble horizon at the formation epoch and subsequently accreted mass surrounding them. Numerical relativity simulation shows that primordial black holes of different masses do not accrete much, which contrasts with a simplistic Newtonian argument. We see that primordial black holes larger than the 'super-horizon' primordial black holes have decreasing energy and worm-hole like struture, suggesting the formation through quamtum processes.

  15. A system for measuring thermal activation energy levels in silicon by thermally stimulated capacitance

    NASA Technical Reports Server (NTRS)

    Cockrum, R. H.

    1982-01-01

    One method being used to determine energy level(s) and electrical activity of impurities in silicon is described. The method is called capacitance transient spectroscopy (CTS). It can be classified into three basic categories: the thermally stimulated capacitance method, the voltage-stimulated capacitance method, and the light-stimulated capacitance method; the first two categories are discussed. From the total change in capacitance and the time constant of the capacitance response, emission rates, energy levels, and trap concentrations can be determined. A major advantage of using CTS is its ability to detect the presence of electrically active impurities that are invisible to other techniques, such as Zeeman effect atomic absorption, and the ability to detect more than one electrically active impurity in a sample. Examples of detection of majority and minority carrier traps from gold donor and acceptor centers in silicon using the capacitance transient spectrometer are given to illustrate the method and its sensitivity.

  16. Variational Calculations of Ro-Vibrational Energy Levels and Transition Intensities for Tetratomic Molecules

    NASA Technical Reports Server (NTRS)

    Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    A description is given of an algorithm for computing ro-vibrational energy levels for tetratomic molecules. The expressions required for evaluating transition intensities are also given. The variational principle is used to determine the energy levels and the kinetic energy operator is simple and evaluated exactly. The computational procedure is split up into the determination of one dimensional radial basis functions, the computation of a contracted rotational-bending basis, followed by a final variational step coupling all degrees of freedom. An angular basis is proposed whereby the rotational-bending contraction takes place in three steps. Angular matrix elements of the potential are evaluated by expansion in terms of a suitable basis and the angular integrals are given in a factorized form which simplifies their evaluation. The basis functions in the final variational step have the full permutation symmetries of the identical particles. Sample results are given for HCCH and BH3.

  17. First-principles approach to calculating energy level alignment at aqueous semiconductor interfaces

    DOE PAGES

    Kharche, Neerav; Muckerman, James T.; Hybertsen, Mark S.

    2014-10-21

    A first-principles approach is demonstrated for calculating the relationship between an aqueous semiconductor interface structure and energy level alignment. The physical interface structure is sampled using density functional theory based molecular dynamics, yielding the interface electrostatic dipole. The GW approach from many-body perturbation theory is used to place the electronic band edge energies of the semiconductor relative to the occupied 1b₁ energy level in water. The application to the specific cases of nonpolar (101¯0 ) facets of GaN and ZnO reveals a significant role for the structural motifs at the interface, including the degree of interface water dissociation and themore » dynamical fluctuations in the interface Zn-O and O-H bond orientations. As a result, these effects contribute up to 0.5 eV.« less

  18. First-principles approach to calculating energy level alignment at aqueous semiconductor interfaces

    SciTech Connect

    Kharche, Neerav; Muckerman, James T.; Hybertsen, Mark S.

    2014-10-21

    A first-principles approach is demonstrated for calculating the relationship between an aqueous semiconductor interface structure and energy level alignment. The physical interface structure is sampled using density functional theory based molecular dynamics, yielding the interface electrostatic dipole. The GW approach from many-body perturbation theory is used to place the electronic band edge energies of the semiconductor relative to the occupied 1benergy level in water. The application to the specific cases of nonpolar (101¯0 ) facets of GaN and ZnO reveals a significant role for the structural motifs at the interface, including the degree of interface water dissociation and the dynamical fluctuations in the interface Zn-O and O-H bond orientations. As a result, these effects contribute up to 0.5 eV.

  19. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.

    2010-01-01

    Black-hole mergers take place in regions of very strong and dynamical gravitational fields, and are among the strongest sources of gravitational radiation. Probing these mergers requires solving the full set of Einstein's equations of general relativity numerically. For more than 40 years, progress towards this goal has been very slow, as numerical relativists encountered a host of difficult problems. Recently, several breakthroughs have led to dramatic progress, enabling stable and accurate calculations of black-hole mergers. This article presents an overview of this field, including impacts on astrophysics and applications in gravitational wave data analysis.

  20. Characterizing Black Hole Mergers

    NASA Technical Reports Server (NTRS)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  1. Infinitely coloured black holes

    NASA Astrophysics Data System (ADS)

    Mavromatos, Nick E.; Winstanley, Elizabeth

    2000-04-01

    We formulate the field equations for SU (icons/Journals/Common/infty" ALT="infty" ALIGN="TOP"/> ) Einstein-Yang-Mills theory, and use an analytic approximation to elucidate the properties of spherically symmetric black hole solutions. This model may be motivated by string theory considerations, given the enormous gauge symmetries which characterize string theory. The solutions simplify considerably in the presence of a negative cosmological constant, particularly for the limiting cases of a very large cosmological constant or very small gauge field. The black holes possess infinite amounts of gauge field hair, and we speculate on possible consequences of this for quantum decoherence, which, however, we do not tackle here.

  2. Euclidean black hole vortices

    NASA Technical Reports Server (NTRS)

    Dowker, Fay; Gregory, Ruth; Traschen, Jennie

    1991-01-01

    We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviors, at the horizon and at infinity, of vortex solutions for the gauge and scalar fields in an abelian Higgs model on a Euclidean Schwarzschild background and interpolate between them by integrating the equations numerically. Calculating the backreaction shows that the effect of the vortex is to cut a slice out of the Schwarzschild geometry. Consequences of these solutions for black hole thermodynamics are discussed.

  3. Quasipotential equation for hydrogen isotopes. Muonic atoms. Ground state energy levels

    NASA Astrophysics Data System (ADS)

    Bakalov, D.

    1980-06-01

    The quasipotential for the electromagnetic interaction of two particles of spin {1}/{2} or 1 with arbitrary electromagnetic interaction of two particles of spin {1}/{2} or 1 with arbitrary electromagnetic structure is constructed in the one-photon approximation. Todorov's quasipotential equation is applied to calculate the ground state energy levels of the muonic atoms pμ, dμ and tμ with accuracy 10 -3 eV.

  4. Calculations of energy levels and lifetimes of low-lying states of barium and radium

    SciTech Connect

    Dzuba, V. A.; Ginges, J. S. M.

    2006-03-15

    We use the configuration-interaction method and many-body perturbation theory to perform accurate calculations of energy levels, transition amplitudes, and lifetimes of low-lying states of barium and radium. Calculations for radium are needed for the planning of measurements of parity- and time-invariance-violating effects which are strongly enhanced in this atom. Calculations for barium are used to control the accuracy of the calculations.

  5. Energy level formula for the Morse oscillator with an additional kinetic coupling potential

    NASA Astrophysics Data System (ADS)

    Fan, Hong-yi; Chen, Bo-zhan; Fan, Yue

    1996-02-01

    Based on the <η| representation which is the common eigenstate of the relative position x1 - x2 and the total momentum P1 + P2 of two particles we derive the energy level formula for a Morse oscillator with an additional kinetic coupling potential. The <η| representation seems to provide a direct and convenient approach for solving certain dynamical problems for two-body systems.

  6. Effect of a metallic gate on the energy levels of a shallow donor

    SciTech Connect

    Slachmuylders, A. F.; Partoens, B.; Peeters, F. M.; Magnus, W.

    2008-02-25

    We have investigated the effect of a metallic gate on the bound states of a shallow donor located near the gate. We calculate the energy spectrum as a function of the distance between the metallic gate and the donor and find an anticrossing behavior in the energy levels for certain distances. We show how a transverse electric field can tune the average position of the electron with respect to the metallic gate and the impurity.

  7. Energy level alignment of single-wall carbon nanotubes on metal surfaces

    NASA Astrophysics Data System (ADS)

    Clair, Sylvain; Kim, Yousoo; Kawai, Maki

    2011-06-01

    We studied the electronic configuration of single-wall carbon nanotubes adsorbed on well-defined Au(111) and Cu(111) surfaces. We found opposite behaviors for their energy-level alignment with metal: nanotubes are p-doped on Au(111) and n-doped on Cu(111). The doping level is not uniquely defined for a particular metal surface but rather exhibits a distribution depending on several uncontrolled factors such as nanotube geometry and adsorption configuration.

  8. Interfacial energy level bending in a crystalline p/p-type organic heterostructure

    SciTech Connect

    Zhu Feng; Grobosch, Mandy; Treske, Uwe; Knupfer, Martin; Huang Lizhen; Ji Shiliang; Yan Donghang

    2011-05-16

    A conduction channel was observed at the heterointerface of the crystalline p-type organic films copper phthalocyanine (CuPc) and 2,5-bis(4-biphenylyl) bithiophene (BP2T). Energy level bending at the interface is confirmed by photoemission spectroscopy, which verifies a charge transfer between CuPc and BP2T. This provides a further route to utilize interfacial electronic properties in functional devices and also documents the importance of reconsidering the interfacial electronic structure of organic heterostructures.

  9. Model for describing non-equilibrium helium plasma energy level population

    NASA Astrophysics Data System (ADS)

    Kavyrshin, D. I.; Chinnov, V. F.; Ageev, A. G.

    2015-11-01

    A new method for calculating the population of excited levels of helium atoms and ions is suggested. The method is based on direct solution of a system of balance equations for all energy levels for which it was possible to obtain process speed constants. The equations include terms for the processes of particle loss and income by excitation and deexcitation, ionization and recombination as well as losses due to diffusion and radiation. The challenge of solution of such large system is also discussed.

  10. Quantum cosmological Friedman models with a Yang-Mills field and positive energy levels

    NASA Astrophysics Data System (ADS)

    Gerhardt, Claus

    2010-02-01

    We prove the existence of a spectral resolution of the Wheeler-DeWitt equation when the matter field is provided by a Yang-Mills field, with or without mass term, if the spatial geometry of the underlying spacetime is homothetic to {\\bb R}^{3} . The energy levels of the resulting quantum model, i.e. the eigenvalues of the corresponding self-adjoint Hamiltonian with a pure point spectrum, are strictly positive. This work has been supported by the DFG.

  11. A detailed analysis of the energy levels configuration existing in the band gap of supersaturated silicon with titanium for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Pérez, E.; Dueñas, S.; Castán, H.; García, H.; Bailón, L.; Montero, D.; García-Hernansanz, R.; García-Hemme, E.; Olea, J.; González-Díaz, G.

    2015-12-01

    The energy levels created in supersaturated n-type silicon substrates with titanium implantation in the attempt to create an intermediate band in their band-gap are studied in detail. Two titanium ion implantation doses (1013 cm-2 and 1014 cm-2) are studied in this work by conductance transient technique and admittance spectroscopy. Conductance transients have been measured at temperatures of around 100 K. The particular shape of these transients is due to the formation of energy barriers in the conduction band, as a consequence of the band-gap narrowing induced by the high titanium concentration. Moreover, stationary admittance spectroscopy results suggest the existence of different energy level configuration, depending on the local titanium concentration. A continuum energy level band is formed when titanium concentration is over the Mott limit. On the other hand, when titanium concentration is lower than the Mott limit, but much higher than the donor impurity density, a quasi-continuum energy level distribution appears. Finally, a single deep center appears for low titanium concentration. At the n-type substrate, the experimental results obtained by means of thermal admittance spectroscopy at high reverse bias reveal the presence of single levels located at around Ec-425 and Ec-275 meV for implantation doses of 1013 cm-2 and 1014 cm-2, respectively. At low reverse bias voltage, quasi-continuously distributed energy levels between the minimum of the conduction bands, Ec and Ec-450 meV, are obtained for both doses. Conductance transients detected at low temperatures reveal that the high impurity concentration induces a band gap narrowing which leads to the formation of a barrier in the conduction band. Besides, the relationship between the activation energy and the capture cross section values of all the energy levels fits very well to the Meyer-Neldel rule. As it is known, the Meyer-Neldel rule typically appears in processes involving multiple excitations, like

  12. A detailed analysis of the energy levels configuration existing in the band gap of supersaturated silicon with titanium for photovoltaic applications

    SciTech Connect

    Pérez, E.; Dueñas, S.; Castán, H.; García, H.; Bailón, L.; Montero, D.; García-Hernansanz, R.; García-Hemme, E.; González-Díaz, G.; Olea, J.

    2015-12-28

    The energy levels created in supersaturated n-type silicon substrates with titanium implantation in the attempt to create an intermediate band in their band-gap are studied in detail. Two titanium ion implantation doses (10{sup 13 }cm{sup -2} and 10{sup 14 }cm{sup -2}) are studied in this work by conductance transient technique and admittance spectroscopy. Conductance transients have been measured at temperatures of around 100 K. The particular shape of these transients is due to the formation of energy barriers in the conduction band, as a consequence of the band-gap narrowing induced by the high titanium concentration. Moreover, stationary admittance spectroscopy results suggest the existence of different energy level configuration, depending on the local titanium concentration. A continuum energy level band is formed when titanium concentration is over the Mott limit. On the other hand, when titanium concentration is lower than the Mott limit, but much higher than the donor impurity density, a quasi-continuum energy level distribution appears. Finally, a single deep center appears for low titanium concentration. At the n-type substrate, the experimental results obtained by means of thermal admittance spectroscopy at high reverse bias reveal the presence of single levels located at around E{sub c}-425 and E{sub c}-275 meV for implantation doses of 10{sup 13 }cm{sup −2} and 10{sup 14 }cm{sup −2}, respectively. At low reverse bias voltage, quasi-continuously distributed energy levels between the minimum of the conduction bands, E{sub c} and E{sub c}-450 meV, are obtained for both doses. Conductance transients detected at low temperatures reveal that the high impurity concentration induces a band gap narrowing which leads to the formation of a barrier in the conduction band. Besides, the relationship between the activation energy and the capture cross section values of all the energy levels fits very well to the Meyer-Neldel rule. As it is known

  13. Control of Electronic Symmetry and Rectification through Energy Level Variations in Bilayer Molecular Junctions.

    PubMed

    Bayat, Akhtar; Lacroix, Jean-Christophe; McCreery, Richard L

    2016-09-21

    Two layers of molecular oligomers were deposited on flat carbon electrode surfaces by electrochemical reduction of diazonium reagents, then a top contact applied to complete a solid-state molecular junction containing a molecular bilayer. The structures and energy levels of the molecular layers included donor molecules with relatively high energy occupied orbitals and acceptors with low energy unoccupied orbitals. When the energy levels of the two molecular layers were similar, the device had electronic characteristics similar to a thick layer of a single molecule, but if the energy levels differed, the current voltage behavior exhibited pronounced rectification. Higher current was observed when the acceptor molecule was biased negatively in eight different bilayer combinations, and the direction of rectification was reversed if the molecular layers were also reversed. Rectification persisted at very low temperature (7 K), and was activationless between 7 and 100 K. The results are a clear example of a "molecular signature" in which electronic behavior is directly affected by molecular structure and orbital energies. The rectification mechanism is discussed, and may provide a basis for rational design of electronic properties by variation of molecular structure.

  14. by ligand exchange: utilizing energy level alignment for efficiently reducing carrier rec ombination

    NASA Astrophysics Data System (ADS)

    Wang, Xia; Kou, Dong-Xing; Zhou, Wen-Hui; Zhou, Zheng-Ji; Wu, Si-Xin; Cao, Xuan

    2014-05-01

    In this work, we employed a convenient one-step synthesis method for synthesizing Cu2ZnSnSe4 (CZTSe) nanocrystals (NCs) in an excess selenium environment. This excess selenium situation enhanced the reaction of metal acetylacetonates with selenium, resulting in the burst nucleation of NCs at relatively low temperatures. The phase morphology and surface and optoelectronic properties of NCs before and after ligand exchange were discussed in depth. It was found that pure tetragonal-phase structure CZTSe NCs with approximately 1.7-eV bandgap could be synthesized. The removal of large organic molecules on CZTSe NCs after ligand exchange by S2- decreased the resistivity. The bandgap of the films after ligand exchange by 550°C selenization was also decreased due to better crystallinity. For potential application in CZTSe solar cells, we constructed an energy level diagram to explain the mutual effect between the absorption layer and CdS layer. Using cyclic voltammetry (CV) measurement, we found that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of CZTSe films shifted down after ligand exchange. After energy level alignment at the CdS/CZTSe interface, a type I band alignment structure was more conveniently formed after ligand exchange. This structure acted as the barrier against injection electrons from ZnO to the CZTSe layer, and recombination would subsequently be depressed.

  15. Pronounced polarization-induced energy level shifts at boundaries of organic semiconductor nanostructures

    PubMed Central

    Cochrane, K. A.; Schiffrin, A.; Roussy, T. S.; Capsoni, M.; Burke, S. A.

    2015-01-01

    Organic semiconductor devices rely on the movement of charge at and near interfaces, making an understanding of energy level alignment at these boundaries an essential element of optimizing materials for electronic and optoelectronic applications. Here we employ low temperature scanning tunneling microscopy and spectroscopy to investigate a model system: two-dimensional nanostructures of the prototypical organic semiconductor, PTCDA (3,4,9,10-perylenetetracarboxylic dianhydride) adsorbed on NaCl (2 ML)/Ag(111). Pixel-by-pixel scanning tunneling spectroscopy allows mapping of occupied and unoccupied electronic states across these nanoislands with sub-molecular spatial resolution, revealing strong electronic differences between molecules at the edges and those in the centre, with energy level shifts of up to 400 meV. We attribute this to the change in electrostatic environment at the boundaries of clusters, namely via polarization of neighbouring molecules. The observation of these strong shifts illustrates a crucial issue: interfacial energy level alignment can differ substantially from the bulk electronic structure in organic materials. PMID:26440933

  16. Energy levels and multipole transition properties of C4+ ion in Debye plasmas

    NASA Astrophysics Data System (ADS)

    Xie, L. Y.; Wang, J. G.; Janev, R. K.; Qu, Y. Z.; Dong, C. Z.

    2012-05-01

    Plasma screening effects on the energy structure and radiative transition properties of helium-like C4+ ions embedded in Debye plasmas are investigated by using the multi-configuration Dirac-Hartree-Fock method incorporating the Debye-Hückel potential for both the electron-nucleus and electron-electron interactions. Seventeen fine-structure energy levels of the low-lying 1 s 2, 1 s2 l( l = s,p) and 1 s3 l'( l' = s,p,d) configurations, as well as the electric-dipole ( E1), magnetic-dipole ( M1) and magnetic-quadrupole ( M2) transition probabilities and oscillator strengths between these levels have been calculated over a wide range of screening parameters. It is found that the plasma screening leads to a decrease of excitation energies and alters the energy levels remarkably. For Δn ≠ 0 transitions, the spontaneous decay spectra are red-shifted and their oscillator strengths and transition probabilities decrease with increasing the interaction screening, while those for the Δn = 0 transitions exhibit opposite patterns. The influence of electron-nucleus and electron-electron screened interactions on the changes of energy levels and transition properties are analyzed. Comparison is made of present results with other data available in the literature for this ion.

  17. Pronounced polarization-induced energy level shifts at boundaries of organic semiconductor nanostructures.

    PubMed

    Cochrane, K A; Schiffrin, A; Roussy, T S; Capsoni, M; Burke, S A

    2015-01-01

    Organic semiconductor devices rely on the movement of charge at and near interfaces, making an understanding of energy level alignment at these boundaries an essential element of optimizing materials for electronic and optoelectronic applications. Here we employ low temperature scanning tunneling microscopy and spectroscopy to investigate a model system: two-dimensional nanostructures of the prototypical organic semiconductor, PTCDA (3,4,9,10-perylenetetracarboxylic dianhydride) adsorbed on NaCl (2 ML)/Ag(111). Pixel-by-pixel scanning tunneling spectroscopy allows mapping of occupied and unoccupied electronic states across these nanoislands with sub-molecular spatial resolution, revealing strong electronic differences between molecules at the edges and those in the centre, with energy level shifts of up to 400 meV. We attribute this to the change in electrostatic environment at the boundaries of clusters, namely via polarization of neighbouring molecules. The observation of these strong shifts illustrates a crucial issue: interfacial energy level alignment can differ substantially from the bulk electronic structure in organic materials. PMID:26440933

  18. Energy level modification in lead sulfide quantum dot photovoltaics through ligand exchange

    NASA Astrophysics Data System (ADS)

    Brown, Patrick; Kim, Donghun; Lunt, Richard; Bawendi, Moungi; Grossman, Jeffrey; Bulovic, Vladimir

    2014-03-01

    The electronic properties of lead sulfide colloidal quantum dots (PbS QDs) can be controlled through modification of QD size and surface chemistry. Novel surface passivation techniques involving organic or inorganic ligands have contributed to a rapid rise in the efficiency of QD photovoltaics, yet the influence of ligand-induced surface dipoles on PbS QD energy levels and photovoltaic device operation is not yet completely understood. Here, the valence band energies of PbS QDs treated with twelve different ligands are measured using ultraviolet photoelectron spectroscopy (UPS), and a valence band shift of up to 0.75 eV is observed between different ligand treatments. Atomistic simulations of ligand binding to pristine PbS(100) and PbS(111) slabs qualitatively reproduce the measured energy level shifts. 1,2-benzenedithiol and 1,3-benzendithiol treatments, which result in valence band energies differing by ~ 0.2 eV, are employed for PbS QDs in three different solar cell architectures, and changes in device performance are correlated with the measured energy level shift. These findings complement the known bandgap-tunability of colloidal QDs and highlight an additional level of control over the electronic properties of PbS QDs.

  19. Control of Electronic Symmetry and Rectification through Energy Level Variations in Bilayer Molecular Junctions.

    PubMed

    Bayat, Akhtar; Lacroix, Jean-Christophe; McCreery, Richard L

    2016-09-21

    Two layers of molecular oligomers were deposited on flat carbon electrode surfaces by electrochemical reduction of diazonium reagents, then a top contact applied to complete a solid-state molecular junction containing a molecular bilayer. The structures and energy levels of the molecular layers included donor molecules with relatively high energy occupied orbitals and acceptors with low energy unoccupied orbitals. When the energy levels of the two molecular layers were similar, the device had electronic characteristics similar to a thick layer of a single molecule, but if the energy levels differed, the current voltage behavior exhibited pronounced rectification. Higher current was observed when the acceptor molecule was biased negatively in eight different bilayer combinations, and the direction of rectification was reversed if the molecular layers were also reversed. Rectification persisted at very low temperature (7 K), and was activationless between 7 and 100 K. The results are a clear example of a "molecular signature" in which electronic behavior is directly affected by molecular structure and orbital energies. The rectification mechanism is discussed, and may provide a basis for rational design of electronic properties by variation of molecular structure. PMID:27563739

  20. Effect of acidity on the energy level of curcumin dye extracted from Curcuma longa L.

    NASA Astrophysics Data System (ADS)

    Agustia, Yuda Virgantara; Suyitno, Arifin, Zainal; Sutanto, Bayu

    2016-03-01

    The purpose of this research is to investigate the effect of acidity on the energy level of curcumin dye. The natural dye, curcumin, was synthesized from Curcuma longa L. using a simple extraction technique. The purification of curcumin dye was conducted in a column of chromatography and its characteristics were studied. Next, the purified curcumin dye was added by benzoic acids until various acidities of 3.0, 3.5, 4.0, 4.5, and 5.0. The absorbance spectra and the functionality groups found in the dyes were detected by ultraviolet-visible spectroscopy and Fourier-transform infrared spectroscopy, respectively. Meanwhile, the energy level of the dyes, EHOMO and ELUMO was measured by cyclic voltammetry. The best energy level of curcumin dye was achieved at pH 3.5 where Ered = -0.37V, ELUMO = -4.28 eV, Eox = 1.15V, EHOMO = -5.83 eV, and Eband gap = 1.55 eV. Therefore, the purified curcumin dye added by benzoic acid was promising for sensitizing the dye-sensitized solar cells.

  1. Crystal field parameters and energy levels scheme of trivalent chromium doped BSO

    SciTech Connect

    Petkova, P.; Andreici, E.-L.; Avram, N. M.

    2014-11-24

    The aim of this paper is to give an analysis of crystal field parameters and energy levels schemes for the above doped material, in order to give a reliable explanation for experimental data. The crystal field parameters have been modeled in the frame of Exchange Charge Model (ECM) of the crystal field theory, taken into account the geometry of systems, with actually site symmetry of the impurity ions. The effect of the charges of the ligands and covalence bonding between chromium cation and oxygen anions, in the cluster approach, also were taken into account. With the obtained values of the crystal field parameters we simulated the scheme of energy levels of chromium ions by diagonalizing the matrix of the Hamiltonian of the doped crystal. The obtained energy levels and estimated Racah parameters B and C were compared with the experimental spectroscopic data and discussed. Comparison with experiment shows that the results are quite satisfactory which justify the model and simulation scheme used for the title system.

  2. Energy transfer and energy level decay processes of Er3+ in water-free tellurite glass

    NASA Astrophysics Data System (ADS)

    Gomes, Laercio; Rhonehouse, Daniel; Nguyen, Dan T.; Zong, Jie; Chavez-Pirson, Arturo; Jackson, Stuart D.

    2015-12-01

    This report details the fundamental spectroscopic properties of a new class of water-free tellurite glasses studied for future applications in mid-infrared light generation. The fundamental excited state decay processes relating to the 4I11/2 → 4I13/2 transition in singly Er3+-doped Tellurium Zinc Lanthanum glass have been investigated using time-resolved fluorescence spectroscopy. The excited state dynamics was analyzed for Er2O3 concentrations between 0.5 mol% and 4 mol%. Selective laser excitation of the 4I11/2 energy level at 972 nm and selective laser excitation of the 4I13/2 energy level at 1485 nm has established that in a similar way to other Er3+-doped glasses, a strong energy-transfer upconversion by way of a dipole-dipole interaction between two excited erbium ions in the 4I13/2 level populates the 4I11/2 upper laser level of the 3 μm transition. The 4I13/2 and 4I11/2 energy levels emitted luminescence with peaks located at 1532 nm and 2734 nm respectively with luminescence efficiencies of 100% and 8% for the higher (4 mol.%) concentration sample. Results from numerical simulations showed that a population inversion is reached at a threshold pumping intensity of ∼57 kW cm-2 for a CW laser pump at 976 nm for [Er2O3] = 2 mol.%.

  3. Resonant nature of intrinsic defect energy levels in PbTe revealed by infrared photoreflectance spectroscopy

    SciTech Connect

    Zhang, Bingpo; Cai, Chunfeng; Jin, Shuqiang; Ye, Zhenyu; Wu, Huizhen; Qi, Zhen

    2014-07-14

    Step-scan Fourier-transform infrared photoreflectance and modulated photoluminescence spectroscopy were used to characterize the optical transitions of the epitaxial PbTe thin film grown by molecular beam epitaxy on BaF{sub 2} (111) substrate in the vicinity of energy gap of lead telluride at 77 K. It is found that the intrinsic defect energy levels in the electronic structure are of resonant nature. The Te-vacancy energy level is located above the conduction band minimum by 29.1 meV. Another defect (V{sub X}) energy level situated below valance band maximum by 18.1 meV is also revealed. Whether it is associated with the Pb vacancy is still not clear. It might also be related to the misfit dislocations stemming from the lattice mismatch between PbTe and BaF{sub 2} substrate. The experimental results support the theory prediction (N. J. Parada and G. W. Pratt, Jr., Phys. Rev. Lett. 22, 180 (1969), N. J. Parada, Phys. Rev. B 3, 2042 (1971)) and are consistent with the reported Hall experimental results (G. Bauer, H. Burkhard, H. Heinrich, and A. Lopez-Otero, J. Appl. Phys. 47, 1721 (1976)).

  4. Resonant nature of intrinsic defect energy levels in PbTe revealed by infrared photoreflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Bingpo; Cai, Chunfeng; Jin, Shuqiang; Ye, Zhenyu; Wu, Huizhen; Qi, Zhen

    2014-07-01

    Step-scan Fourier-transform infrared photoreflectance and modulated photoluminescence spectroscopy were used to characterize the optical transitions of the epitaxial PbTe thin film grown by molecular beam epitaxy on BaF2 (111) substrate in the vicinity of energy gap of lead telluride at 77 K. It is found that the intrinsic defect energy levels in the electronic structure are of resonant nature. The Te-vacancy energy level is located above the conduction band minimum by 29.1 meV. Another defect (VX) energy level situated below valance band maximum by 18.1 meV is also revealed. Whether it is associated with the Pb vacancy is still not clear. It might also be related to the misfit dislocations stemming from the lattice mismatch between PbTe and BaF2 substrate. The experimental results support the theory prediction (N. J. Parada and G. W. Pratt, Jr., Phys. Rev. Lett. 22, 180 (1969), N. J. Parada, Phys. Rev. B 3, 2042 (1971)) and are consistent with the reported Hall experimental results (G. Bauer, H. Burkhard, H. Heinrich, and A. Lopez-Otero, J. Appl. Phys. 47, 1721 (1976)).

  5. Energy Level Alignment at Aqueous GaN and ZnO Interfaces

    NASA Astrophysics Data System (ADS)

    Hybertsen, Mark S.; Kharche, Neerav; Muckerman, James T.

    2014-03-01

    Electronic energy level alignment at semiconductor-electrolyte interfaces is fundamental to electrochemical activity. Motivated in particular by the search for new materials that can be more efficient for photocatalysis, we develop a first principles method to calculate this alignment at aqueous interfaces and demonstrate it for the specific case of non-polar GaN and ZnO interfaces with water. In the first step, density functional theory (DFT) based molecular dynamics is used to sample the physical interface structure and to evaluate the electrostatic potential step at the interface. In the second step, the GW approach is used to evaluate the reference electronic energy level separately in the bulk semiconductor (valence band edge energy) and in bulk water (the 1b1 energy level), relative to the internal electrostatic energy reference. Use of the GW approach naturally corrects for errors inherent in the use of Kohn-Sham energy eigenvalues to approximate the electronic excitation energies in each material. With this predicted interface alignment, specific redox levels in water, with potentials known relative to the 1b1 level, can then be compared to the semiconductor band edge positions. Our results will be discussed in the context of experiments in which photoexcited GaN and ZnO drive the hydrogen evolution reaction. Research carried out at Brookhaven National Laboratory under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.

  6. Quantum Mechanics on a Mobius Strip: Energy Levels, Symmetries, and Level Splitting in a Magnetic Field

    NASA Astrophysics Data System (ADS)

    Li, Zehao; Ram-Mohan, Ramdas

    2012-02-01

    We investigate the energy levels of an electron on a M"obius strip. Schr"odinger's equation on this curved surface is shown to have terms that do not have invariance under parity transformation in parameter space for the strip. The double degeneracy of energy levels that exists for flat cylindrical rings is shown to be removed for the pairs of energies in the M"obius strip due to parity symmetry breaking. The orbital angular momentum is found to have approximately not only integer but also half-integer values of . The splitting of the energy levels in an external magnetic field is displayed. The effects of multiple twists are investigated to further clarify that the parity symmetry breaking is the effect of the curved geometry, while the appearance of half-integer angular momentum states is a topological effect. The implications for twisted rings composed of graphene will be discussed, and carrier transport through the M"obius strip will be considered. This work was supported by AFLR/DARPA under grant FA8650-10-1-7046.

  7. Hovering black holes from charged defects

    NASA Astrophysics Data System (ADS)

    Horowitz, Gary T.; Iqbal, Nabil; Santos, Jorge E.; Way, Benson

    2015-05-01

    We construct the holographic dual of an electrically charged, localized defect in a conformal field theory at strong coupling, by applying a spatially dependent chemical potential. We find that the infrared behaviour of the spacetime depends on the spatial falloff of the potential. Moreover, for sufficiently localized defects with large amplitude, we find that a new gravitational phenomenon occurs: a spherical extremal charged black hole nucleates in the bulk: a hovering black hole. This is a second order quantum phase transition. We construct this new phase with several profiles for the chemical potential and study its properties. We find an apparently universal behaviour for the entropy of the defect as a function of its amplitude. We comment on the possible field theory implications of our results.

  8. Tunnelling from black holes and tunnelling into white holes

    NASA Astrophysics Data System (ADS)

    Chatterjee, Bhramar; Ghosh, A.; Mitra, P.

    2008-03-01

    Hawking radiation is nowadays being understood as tunnelling through black hole horizons. Here, the extension of the Hamilton-Jacobi approach to tunnelling for non-rotating and rotating black holes in different non-singular coordinate systems not only confirms this quantum emission from black holes but also reveals the new phenomenon of absorption into white holes by quantum mechanical tunnelling. The rôle of a boundary condition of total absorption or emission is also clarified.

  9. A New Way To Weigh Giant Black Holes

    NASA Astrophysics Data System (ADS)

    2008-07-01

    How do you weigh the biggest black holes in the universe? One answer now comes from a completely new and independent technique that astronomers have developed using data from NASA's Chandra X-ray Observatory. By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, scientists have determined the mass of the galaxy’s supermassive black hole. The method, applied for the first time, gives results that are consistent with a traditional technique. Astronomers have been seeking out different, independent ways of precisely weighing the largest supermassive black holes, that is, those that are billions of times more massive than the Sun. Until now, methods based on observations of the motions of stars or of gas in a disk near such large black holes had been used. "This is tremendously important work since black holes can be elusive, and there are only a couple of ways to weigh them accurately," said Philip Humphrey of the University of California at Irvine, who led the study. "It's reassuring that two very different ways to measure the mass of a big black hole give such similar answers." AnimationChandra X-ray Image NGC 4649 is now one of only a handful of galaxies for which the mass of a supermassive black hole has been measured with two different methods. In addition, this new X-ray technique confirms that the supermassive black hole in NGC 4649 is one of the largest in the local universe with a mass about 3.4 billion times that of the Sun, about a thousand times bigger than the black hole at the center of our galaxy. The new technique takes advantage of the gravitational influence the black hole has on the hot gas near the center of the galaxy. As gas slowly settles towards the black hole, it gets compressed and heated. This causes a peak in the temperature of the gas right near the center of the galaxy. The more massive the black hole, the bigger the temperature peak detected by Chandra. People Who Read This Also Read

  10. When Black Holes Collide

    NASA Technical Reports Server (NTRS)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  11. Hot-hole photodetectors

    NASA Astrophysics Data System (ADS)

    2014-05-01

    By injecting high-energy charge carriers (dubbed 'hot holes') into a semiconductor, scientists have succeeded in realizing photodetectors capable of detecting ultralong wavelengths. Unil Perera from Georgia State University in the USA explains how the devices work and how they can be improved.

  12. Drilling Square Holes.

    ERIC Educational Resources Information Center

    Smith, Scott G.

    1993-01-01

    A Reuleaux triangle is constructed by drawing an arc connecting each pair of vertices of an equilateral triangle with radius equal to the side of the triangle. Investigates the application of drilling a square hole using a drill bit in the shape of a Reuleaux triangle. (MDH)

  13. Laser bottom hole assembly

    DOEpatents

    Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

    2014-01-14

    There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

  14. Moulting Black Holes

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; Chowdhury, Borun D.; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2012-03-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no black holes were thought to exist.

  15. The Antarctic Ozone Hole.

    ERIC Educational Resources Information Center

    Stolarski, Richard S.

    1988-01-01

    Discusses the Airborne Antarctic Ozone Experiment (1987) and the findings of the British Antarctic Survey (1985). Proposes two theories for the appearance of the hole in the ozone layer over Antarctica which appears each spring; air pollution and natural atmospheric shifts. Illustrates the mechanics of both. Supports worldwide chlorofluorocarbon…

  16. Black hole magnetospheres

    SciTech Connect

    Nathanail, Antonios; Contopoulos, Ioannis

    2014-06-20

    We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.

  17. "Holes": Folklore Redux.

    ERIC Educational Resources Information Center

    Mascia, Elizabeth G.

    2001-01-01

    Demonstrates that a careful reading of the book for young adults, "Holes" by Louis Sachar, reveals how this contemporary story is grounded in folklore, and that it is this debt to folk literature that allows readers to accept an improbable plot. Shows how the story weaves together elements from traditional folk literature and stretches them across…

  18. Roof bolt hole groover

    SciTech Connect

    Not Available

    1985-11-05

    A hole groover comprising a pair of grooving bits radially protruding from the surface of a drill rod and connected to swivel upwardly and downwardly near the end of the drill rod where the drill bit is connected. A connecting rod is connected to the inside ends of the groove bits and causes arcuate movement of the grooving bits as it reciprocates. The hole groover further includes a gear box which is connectable to a rotary drilling unit which converts rotational movement of the rotary drill until to reciprocating movement of a lever. The lever is connected to the connecting rod which causes movement of the grooving bits. The device is readily adaptable to be connected to most rotary drill units and the depth and intervals of the grooves can be easily controlled by adjusting the length of the grooving bits and the gear ratios. The device enables grooves to be cut in a wall hole surface, concurrently with the drilling of the hole.

  19. Aspects of hairy black holes

    SciTech Connect

    Anabalón, Andrés; Astefanesei, Dumitru

    2015-03-26

    We review the existence of exact hairy black holes in asymptotically flat, anti-de Sitter and de Sitter space-times. We briefly discuss the issue of stability and the charging of the black holes with a Maxwell field.

  20. Slowly balding black holes

    NASA Astrophysics Data System (ADS)

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-01

    The “no-hair” theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively “frozen in” the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes NB=eΦ∞/(πcℏ), where Φ∞≈2π2BNSRNS3/(PNSc) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole’s magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  1. Black hole phase transitions in Horava-Lifshitz gravity

    SciTech Connect

    Cao Qiaojun; Chen Yixin; Shao Kainan

    2011-03-15

    We study black hole phase transitions in (deformed) Horava-Lifshitz (H-L) gravity, including the charged/uncharged topological black holes and KS black hole. Stability analysis and state space geometry are both used. We find interesting phase structures in these black holes, some of the properties are never observed in Einstein gravity. Particularly, the stability properties of black holes in H-L gravity with small radius change dramatically, which can be considered as a leak of information about the small scale behavior of spacetime. A new black hole local phase transition in H-L gravity which cannot be revealed by thermodynamical metrics has been found. There is an infinite discontinuity at the specific heat curve for charged black hole in H-L gravity with hyperbolic event horizon. However, this discontinuity does not have a corresponding curvature singularity of thermodynamical metrics. Our results may provide new insights towards a better understanding of the H-L gravity, as well as black hole thermodynamics.

  2. A RAPIDLY SPINNING BLACK HOLE POWERS THE EINSTEIN CROSS

    SciTech Connect

    Reynolds, Mark T.; Miller, Jon M.; Reis, Rubens C.; Walton, Dominic J.

    2014-09-01

    Observations over the past 20 yr have revealed a strong relationship between the properties of the supermassive black hole lying at the center of a galaxy and the host galaxy itself. The magnitude of the spin of the black hole will play a key role in determining the nature of this relationship. To date, direct estimates of black hole spin have been restricted to the local universe. Herein, we present the results of an analysis of ∼0.5 Ms of archival Chandra observations of the gravitationally lensed quasar Q 2237+305 (aka the {sup E}instein-cross{sup )}, lying at a redshift of z = 1.695. The boost in flux provided by the gravitational lens allows constraints to be placed on the spin of a black hole at such high redshift for the first time. Utilizing state of the art relativistic disk reflection models, the black hole is found to have a spin of a{sub ∗}=0.74{sub −0.03}{sup +0.06} at the 90% confidence level. Placing a lower limit on the spin, we find a {sub *} ≥ 0.65 (4σ). The high value of the spin for the ∼10{sup 9} M {sub ☉} black hole in Q 2237+305 lends further support to the coherent accretion scenario for black hole growth. This is the most distant black hole for which the spin has been directly constrained to date.

  3. A Rapidly Spinning Black Hole Powers the Einstein Cross

    NASA Astrophysics Data System (ADS)

    Reynolds, Mark T.; Walton, Dominic J.; Miller, Jon M.; Reis, Rubens C.

    2014-09-01

    Observations over the past 20 yr have revealed a strong relationship between the properties of the supermassive black hole lying at the center of a galaxy and the host galaxy itself. The magnitude of the spin of the black hole will play a key role in determining the nature of this relationship. To date, direct estimates of black hole spin have been restricted to the local universe. Herein, we present the results of an analysis of ~0.5 Ms of archival Chandra observations of the gravitationally lensed quasar Q 2237+305 (aka the "Einstein-cross"), lying at a redshift of z = 1.695. The boost in flux provided by the gravitational lens allows constraints to be placed on the spin of a black hole at such high redshift for the first time. Utilizing state of the art relativistic disk reflection models, the black hole is found to have a spin of a_* = 0.74^{+0.06}_{-0.03} at the 90% confidence level. Placing a lower limit on the spin, we find a * >= 0.65 (4σ). The high value of the spin for the ~109 M ⊙ black hole in Q 2237+305 lends further support to the coherent accretion scenario for black hole growth. This is the most distant black hole for which the spin has been directly constrained to date.

  4. Electron and hole transport in ambipolar, thin film pentacene transistors

    SciTech Connect

    Saudari, Sangameshwar R.; Kagan, Cherie R.

    2015-01-21

    Solution-processed, ambipolar, thin-film pentacene field-effect transistors were employed to study both electron and hole transport simultaneously in a single, organic solid-state device. Electron and hole mobilities were extracted from the respective unipolar saturation regimes and show thermally activated behavior and gate voltage dependence. We fit the gate voltage dependent saturation mobility to a power law to extract the characteristic Meyer-Neldel (MN) energy, a measure of the width of the exponential distribution of localized states extending into the energy gap of the organic semiconductor. The MN energy is ∼78 and ∼28 meV for electrons and holes, respectively, which reflects a greater density of localized tail states for electrons than holes. This is consistent with the lower measured electron than hole mobility. For holes, the well-behaved linear regime allows for four-point probe measurement of the contact resistance independent mobility and separate characterization of the width of the localized density of states, yielding a consistent MN energy of 28 meV.

  5. Devils Hole, Nevada: revisited

    NASA Astrophysics Data System (ADS)

    Spötl, C.; Dublyansky, Y.

    2012-04-01

    Among the ever increasing number of caves visited and studied by paleoclimate scientists around the globe one site is special for a number of reasons. First described in the literature in 1988, Devils Hole is a geometrically simple cave developed along an extensional fracture in the Amargosa Desert of SW Nevada. The deeper portion of this cavity is phreatic and part of a regional aquifer whose lowest discharge point is Death Valley. Landmark studies by Ike Winograd's team examined thick calcite crusts present on the walls of this and a neighboring cave (termed Devils Hole #2) and retrieved one of the most remarkable (and thought-provoking) isotope proxy records covering the last half million of years (1992). More recently, Coplen (2007) scrutinized the stable isotope systematics at Devils Hole. His results suggest that this setting represents a rare example of inorganic calcite precipitation essentially at isotopic equilibrium. We obtained permission from the Death Valley National Park Service to study and sample Devils Hole #2. While previous studies were based on samples from the phreatic zone we cored the calcite crust just above the groundwater table in an attempt to extend the original record further back in time and to obtain direct paleowater isotope data. Stable isotope data obtained along one core show a very high degree of similarity with the published DH11 core and a first set of U-series dates confirms the stratigraphy down to 476 ka. Older calcite also shows glacial-interglacial oscillations in both carbon and oxygen isotopes. A tentative correlation with Antarctic and deep-sea isotope records suggests that the lower part of the calcite is ca. 800 ka old (i.e. MIS 20). The cores show petrographic evidence of falling groundwater levels during MIS 9, 7 and 5e, but there are no indications of major hiati. Interestingly, growth at our drill location ended shortly after 20 ka BP, i.e. much later than at the subaqueous site in Devils Hole proper where DH11

  6. Binary Black Holes produced in Globular Clusters

    NASA Astrophysics Data System (ADS)

    Rodriguez, Carl; Morscher, Meagan; Pattabiraman, Bharath; Chatterjee, Sourav; Rasio, Fred

    2015-04-01

    The mergers of binary black holes will be one of the most promising sources for gravitational-wave astronomy; however, the number of sources expected to form dynamically within the dense environments of globular clusters is highly uncertain. We use a Monte Carlo technique to explore the stellar dynamics of globular clusters. This approach can model systems with ~106 stars and realistic stellar physics, enabling the study of even the most massive of galactic globular clusters. We have produced a collection of globular cluster models with structural properties similar to those observed in the Milky Way. We explore the population of binary black holes produced in these models, including the distribution of masses, semi-major axes, and eccentricities. We find that a typical Milky Way globular cluster can produce hundreds of black hole binaries, several tens of which will coalesce within one Hubble time. We use these models to simulate the globular cluster population of a single Milky Way-equivalent galaxy, providing us with the first realistic merger rate of dynamically formed binary black holes in the local universe.

  7. Fast magnetoacoustic wave trains in coronal holes

    NASA Astrophysics Data System (ADS)

    Pascoe, D. J.; Nakariakov, V. M.; Kupriyanova, E. G.

    2014-08-01

    Context. Rapidly propagating coronal EUV disturbances recently discovered in the solar corona are interpreted in terms of guided fast magnetoacoustic waves. Fast magnetoacoustic waves experience geometric dispersion in waveguides, which causes localised, impulsive perturbations to develop into quasi-periodic wave trains. Aims: We consider the formation of fast wave trains in a super-radially expanding coronal hole modelled by a magnetic funnel with a field-aligned density profile that is rarefied in comparison to the surrounding plasma. This kind of structure is typical of coronal holes, and it forms a fast magnetoacoustic anti-waveguide as a local maximum in the Alfvén speed. Methods: We performed 2D MHD numerical simulations for impulsively generated perturbations to the system. Both sausage and kink perturbations are considered and the role of the density contrast ratio investigated. Results: The anti-waveguide funnel geometry refracts wave energy away from the structure. However, in this geometry the quasi-periodic fast wave trains are found to appear, too, and so can be associated with the observed rapidly propagating coronal EUV disturbances. The wave trains propagate along the external edge of the coronal hole. The fast wave trains generated in coronal holes exhibit less dispersive evolution than in the case of a dense waveguide. Conclusions: We conclude that an impulsive energy release localised in a coronal plasma inhomogeneity develops into a fast wave train for both kink and sausage disturbances and for both waveguide and anti-waveguide transverse plasma profiles.

  8. Energy levels and radiative rates for transitions in Mg-like iron, cobalt and nickel

    SciTech Connect

    Aggarwal, K.M. . E-mail: k.aggarwal@qub.ac.uk; Tayal, Vikas; Gupta, G.P.; Keenan, F.P.

    2007-09-15

    Energy levels and radiative rates for electric dipole (E1) transitions among the lowest 141 levels of the (1s{sup 2}2s{sup 2}2p{sup 6}) 3l{sup 2}, 3l3l', and 3l4l configurations of Fe XV, Co XVI, and Ni XVII are calculated through the CIV3 code using extensive configuration-interaction (CI) wavefunctions. The important relativistic effects are included through the Breit-Pauli approximation. In order to keep the calculated energy splittings close to the experimental values, we have made small adjustments to the diagonal elements of the Hamiltonian matrices. The energy levels, including their orderings, are in excellent agreement with the available experimental results for all three ions. However, experimental energies are only available for a few levels. Since mixing among some levels is found to be very strong, it becomes difficult to identify these uniquely. Additionally, some discrepancies with other theoretical work (particularly for Ni XVII) are very large. Therefore, in order to confirm the level ordering as well as to assess the accuracy of energy levels and radiative rates, we have performed two other independent calculations using the GRASP and FAC codes. These codes are fully relativistic, but the CI in the calculations is limited to the basic (minimum) configurations only. This enables us to assess the importance of including elaborate CI for moderately charged ions. Additionally, we report results for electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions, and list lifetimes for all levels. Comparisons are made with other available experimental and theoretical results, and the accuracy of the present results is assessed.

  9. Potential energy surface and rovibrational energy levels of the H2-CS van der Waals complex.

    PubMed

    Denis-Alpizar, Otoniel; Stoecklin, Thierry; Halvick, Philippe; Dubernet, Marie-Lise; Marinakis, Sarantos

    2012-12-21

    Owing to its large dipole, astrophysicists use carbon monosulfide (CS) as a tracer of molecular gas in the interstellar medium, often in regions where H(2) is the most abundant collider. Predictions of the rovibrational energy levels of the weakly bound complex CS-H(2) (not yet observed) and also of rate coefficients for rotational transitions of CS in collision with H(2) should help to interpret the observed spectra. This paper deals with the first goal, i.e., the calculation of the rovibrational energy levels. A new four-dimensional intermolecular potential energy surface for the H(2)-CS complex is presented. Ab initio potential energy calculations were carried out at the coupled-cluster level with single and double excitations and a perturbative treatment of triple excitations, using a quadruple-zeta basis set and midbond functions. The potential energy surface was obtained by an analytic fit of the ab initio data. The equilibrium structure of the H(2)-CS complex is found to be linear with the carbon pointing toward H(2) at the intermolecular separation of 8.6 a(o). The corresponding well depth is -173 cm(-1). The potential was used to calculate the rovibrational energy levels of the para-H(2)-CS and ortho-H(2)-CS complexes. The present work provides the first theoretical predictions of these levels. The calculated dissociation energies are found to be 35.9 cm(-1) and 49.9 cm(-1), respectively, for the para and ortho complexes. The second virial coefficient for the H(2)-CS pair has also been calculated for a large range of temperature. These results could be used to assign future experimental spectra and to check the accuracy of the potential energy surface.

  10. Experimental Energy Levels of HD18O and D_218O

    NASA Astrophysics Data System (ADS)

    Mikhailenko, S. N.; Naumenko, O. V.; Tashkun, S. A.; Liu, A.-W.; Hu, S.-M.

    2010-06-01

    Extended sets of experimental energy levels of HD18O and D_218O have been obtained as the result of the analysis of recent high-resolution spectra and previously reported data. Spectra of the enriched by deuterium and oxygen-18 water samples were recorded with a Bruker IFS 120HR spectrometer at room temperature in the 1000 - 9200 cm-1 range a,b for this purpose. The RITZ code h was used for analysis of the rotation-vibration transitions and the energy levels determination. New energy levels as well as comparison with previous experimental and theoretical studies will be presented. This work was supported by Grant nos. 06-03-39014 and 10-05-91176 of RFBR (Russia) and by Grant nos. 20903085 and 10574124 of NSFC (China). Work of SNM and SAT was also partly supported by CRDF (USA) Grant RUG1-2954-TO-09 and by RFBR. Grant 09-05-92508. A.-W. Liu et al., J. Mol. Spectrosc. 237, 149-162 (2006). H.-Y. Ni et al., Mol. Phys. 106, 1793-1801 (2008). J. Bellet et al., J. Mol. Spectrosc. 47, 388-402 (1973). J.W.C. Johns, J. Opt. Soc. Am. B2, 1340-1354 (1985). R.A. Toth, J. Mol. Spectrosc. 162, 41-54 (1993). W.F. Wang et al., J. Mol. Spectrosc. 176, 226-228 (1996). R.A. Toth, J. Mol. Structure, 742, 49-68 (2005). S.N. Mikhailenko et al., JQSRT, 110, 597-608 (2009). A. Liu et al., JQSRT, 110, 1781-1800 (2009). O.V. Naumenko et al., JQSRT, 111, 36-44 (2010).

  11. Corrections to the energy levels of a spin-zero particle bound in a strong field

    SciTech Connect

    Lee, R. N.; Milstein, A. I.; Karshenboim, S. G.

    2006-01-15

    Formulas for the corrections to the energy levels and wave functions of a spin-zero particle bound in a strong field are derived. The general case of the sum of a Lorentz-scalar potential and zero component of a Lorentz-vector potential is considered. The forms of the corrections differ essentially from those for spin-(1/2) particles. As an example of application of our results, we evaluated the electric polarizability of a ground state of a spin-zero particle bound in a strong Coulomb field.

  12. Additions to the spectrum and energy levels and critical compilation of doubly ionized boron, B III

    NASA Astrophysics Data System (ADS)

    Kramida, A. E.; Ryabtsev, A. N.; Ekberg, J. O.; Kink, I.; Mannervik, S.; Martinson, I.

    2008-08-01

    We have undertaken the study of the Li-like spectrum of doubly ionized boron, B III. The spectroscopic data have been obtained with beam-foil spectroscopy and high-resolution spark spectroscopy. The experimental work was combined with theoretical calculations using ab initio and semi-empirical techniques. About 50 new transitions have been observed, and most of the previously known lines have been measured with improved accuracy. We have also critically evaluated all previous and recent data for this spectrum. Complete data on wavelengths and energy levels based on this analysis are tabulated.

  13. Diagrammatic treatment of coherent backscattering of intense light by cold atoms with degenerate energy levels

    NASA Astrophysics Data System (ADS)

    Shatokhin, V. N.; Blattmann, R.; Wellens, T.; Buchleitner, A.

    2014-08-01

    We present a generalization of the diagrammatic pump-probe approach to coherent backscattering (CBS) of intense laser light for atoms with degenerate energy levels. We employ this approach for a characterization of the double-scattering signal from optically pumped atoms with the transition Jg→Je=Jg+1 in the helicity-preserving polarization channel. We show that, in the saturation regime, the internal degeneracy becomes manifest for atoms with Jg≥1, leading to a faster decrease of the CBS enhancement factor with increasing saturation parameter than in the nondegenerate case.

  14. Energy levels and transition probabilities in doubly-ionized erbium (Er III).

    NASA Astrophysics Data System (ADS)

    Wyart, J.-F.; Blaise, J.; Bidelman, W. P.; Cowley, C. R.

    1997-11-01

    The spectrum of Er III reported by Becher (1966) was reanalysed with the support of new predictions of energies and transition probabilities. The number of energy levels was increased from 45 to 115, including two levels of 4f117s and the levels 3F3, 3F2 and 1G4 of the ground configuration 4f12. All 470 classified lines are reported with transition probabilities for most of them. Several of these lines had not yet been attributed to Er III in the spectrum of the star HR 465.

  15. Energy levels and lifetimes of Nd IV, Pm IV, Sm IV, and Eu IV

    SciTech Connect

    Dzuba, V. A.; Safronova, U. I.; Johnson, W. R.

    2003-09-01

    To address the shortage of experimental data for electron spectra of triply ionized rare-earth elements we have calculated energy levels and lifetimes of 4f{sup n+1} and 4f{sup n}5d configurations of Nd IV (n=2), Pm IV (n=3), Sm IV (n=4), and Eu IV (n=5) using Hartree-Fock and configuration-interaction methods. To control the accuracy of our calculations we also performed similar calculations for Pr III, Nd III, and Sm III, for which experimental data are available. The results are important, in particular, for physics of magnetic garnets.

  16. Effects of Dietary Energy Levels on the Physiological Parameters and Reproductive Performance of Gestating Gilts.

    PubMed

    Jin, S S; Jung, S W; Jang, J C; Chung, W L; Jeong, J H; Kim, Y Y

    2016-07-01

    This experiment was conducted to investigate the effects of dietary energy levels on the physiological parameters and reproductive performance of gestating first parity sows. A total of 52 F1 gilts (Yorkshire×Landrace) were allocated to 4 dietary treatments using a completely randomized design. Each treatment contained diets with 3,100, 3,200, 3,300, or 3,400 kcal of metabolizable energy (ME)/kg, and the daily energy intake of the gestating gilts in each treatment were 6,200, 6,400, 6,600, and 6,800 kcal of ME, respectively. During gestation, the body weight (p = 0.04) and weight gain (p = 0.01) of gilts linearly increased with increasing dietary energy levels. Backfat thickness was not affected at d110 of gestation by dietary treatments, but increased linearly (p = 0.05) from breeding to d 110 of gestation. There were no significant differences on the litter size or litter birth weight. During lactation, the voluntary feed intake of sows tended to decrease when the dietary energy levels increased (p = 0.08). No difference was observed in backfat thickness of the sows within treatments; increasing energy levels linearly decreased the body weight of sows (p<0.05) at d 21 of lactation and body weight gain during lactation (p<0.01). No significant differences were observed in the chemical compositions of colostrum and milk. Therefore, these results indicated that high-energy diets influenced the bodyweight and backfat thickness of sows during gestation and lactation. NRC (2012) suggested that the energy requirement of the gestation gilt should be between 6,678 and 7,932 kcal of ME/d. Similarly, our results suggested that 3,100 kcal of ME/kg is not enough to maintain the reproductive performance for gilts during gestation with 2 kg feed daily. Gilts in the treatment 3,400 kcal of ME/kg have a higher weaning number of piglets, but bodyweight and backfat loss were higher than other treatments during lactation. But bodyweight and backfat loss were higher than other

  17. Effects of Dietary Energy Levels on the Physiological Parameters and Reproductive Performance of Gestating Gilts

    PubMed Central

    Jin, S. S.; Jung, S. W.; Jang, J. C.; Chung, W. L.; Jeong, J. H.; Kim, Y. Y.

    2016-01-01

    This experiment was conducted to investigate the effects of dietary energy levels on the physiological parameters and reproductive performance of gestating first parity sows. A total of 52 F1 gilts (Yorkshire×Landrace) were allocated to 4 dietary treatments using a completely randomized design. Each treatment contained diets with 3,100, 3,200, 3,300, or 3,400 kcal of metabolizable energy (ME)/kg, and the daily energy intake of the gestating gilts in each treatment were 6,200, 6,400, 6,600, and 6,800 kcal of ME, respectively. During gestation, the body weight (p = 0.04) and weight gain (p = 0.01) of gilts linearly increased with increasing dietary energy levels. Backfat thickness was not affected at d110 of gestation by dietary treatments, but increased linearly (p = 0.05) from breeding to d 110 of gestation. There were no significant differences on the litter size or litter birth weight. During lactation, the voluntary feed intake of sows tended to decrease when the dietary energy levels increased (p = 0.08). No difference was observed in backfat thickness of the sows within treatments; increasing energy levels linearly decreased the body weight of sows (p<0.05) at d 21 of lactation and body weight gain during lactation (p<0.01). No significant differences were observed in the chemical compositions of colostrum and milk. Therefore, these results indicated that high-energy diets influenced the bodyweight and backfat thickness of sows during gestation and lactation. NRC (2012) suggested that the energy requirement of the gestation gilt should be between 6,678 and 7,932 kcal of ME/d. Similarly, our results suggested that 3,100 kcal of ME/kg is not enough to maintain the reproductive performance for gilts during gestation with 2 kg feed daily. Gilts in the treatment 3,400 kcal of ME/kg have a higher weaning number of piglets, but bodyweight and backfat loss were higher than other treatments during lactation. But bodyweight and backfat loss were higher than other

  18. COMPREHENSIVE OBSERVATIONS OF THE ULTRAVIOLET SPECTRUM AND IMPROVED ENERGY LEVELS FOR SINGLY IONIZED CHROMIUM (Cr II)

    SciTech Connect

    Sansonetti, Craig J.; Nave, Gillian; Reader, Joseph; Kerber, Florian

    2012-10-15

    We report new observations of the spectrum of singly ionized chromium (Cr II) in the region 1142-3954 A. The spectra were recorded with the National Institute of Standards and Technology 10.7 m normal-incidence vacuum spectrograph and FT700 vacuum ultraviolet Fourier transform spectrometer. More than 3600 lines are classified as transitions among 283 even and 368 odd levels. The new spectral data are used to re-optimize the energy levels, reducing their uncertainties by a typical factor of 20.

  19. Black Hole Hunters Set New Distance Record

    NASA Astrophysics Data System (ADS)

    2010-01-01

    Astronomers using ESO's Very Large Telescope have detected, in another galaxy, a stellar-mass black hole much farther away than any other previously known. With a mass above fifteen times that of the Sun, this is also the second most massive stellar-mass black hole ever found. It is entwined with a star that will soon become a black hole itself. The stellar-mass black holes [1] found in the Milky Way weigh up to ten times the mass of the Sun and are certainly not be taken lightly, but, outside our own galaxy, they may just be minor-league players, since astronomers have found another black hole with a mass over fifteen times the mass of the Sun. This is one of only three such objects found so far. The newly announced black hole lies in a spiral galaxy called NGC 300, six million light-years from Earth. "This is the most distant stellar-mass black hole ever weighed, and it's the first one we've seen outside our own galactic neighbourhood, the Local Group," says Paul Crowther, Professor of Astrophysics at the University of Sheffield and lead author of the paper reporting the study. The black hole's curious partner is a Wolf-Rayet star, which also has a mass of about twenty times as much as the Sun. Wolf-Rayet stars are near the end of their lives and expel most of their outer layers into their surroundings before exploding as supernovae, with their cores imploding to form black holes. In 2007, an X-ray instrument aboard NASA's Swift observatory scrutinised the surroundings of the brightest X-ray source in NGC 300 discovered earlier with the European Space Agency's XMM-Newton X-ray observatory. "We recorded periodic, extremely intense X-ray emission, a clue that a black hole might be lurking in the area," explains team member Stefania Carpano from ESA. Thanks to new observations performed with the FORS2 instrument mounted on ESO's Very Large Telescope, astronomers have confirmed their earlier hunch. The new data show that the black hole and the Wolf-Rayet star dance

  20. Hole-to-surface resistivity measurements at Gibson Dome (drill hole GD-1) Paradox basin, Utah

    USGS Publications Warehouse

    Daniels, J.J.

    1984-01-01

    Hole-to-surface resistivity measurements were made in a deep drill hole (GD-1), in San Juan County, Utah, which penetrated a sequence of sandstone, shale, and evaporite. These measurements were made as part of a larger investigation to study the suitability of an area centered around the Gibson Dome structure for nuclear waste disposal. The magnitude and direction of the total electric field resulting from a current source placed in a drill hole is calculated from potential difference measurements for a grid of closely-spaced stations. A contour map of these data provides a detailed map of the distribution of the electric field away from the drill hole. Computation of the apparent resistivity from the total electric field helps to interpret the data with respect to the ideal situation of a layered earth. Repeating the surface measurements for different source depths gives an indication of variations in the geoelectric section with depth. The quantitative interpretation of the field data at Gibson Dome was hindered by the pressure of a conductive borehole fluid. However, a qualitative interpretation of the field data indicates the geoelectric section around drill hole GD-1 is not perfectly layered. The geoelectric section appears to dip to the northwest, and contains anomalies in the resistivity distribution that may be representative of localized thickening or folding of the salt layers.

  1. Interplanetary magnetic holes - Theory

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Lemaire, J. F.

    1978-01-01

    Magnetic holes in the interplanetary medium are explained as stationary nonpropagating equilibrium structures in which there are field-aligned enhancements of the plasma density and/or temperature. Magnetic antiholes are considered to be associated with depressions in the plasma pressure. In this model the observed changes in the magnetic field intensity and direction are due to diamagnetic currents that are carried by ions which drift in a sheath as the result of gradients in the magnetic field and in the plasma pressure within the sheath. The thickness of the sheaths that we consider is approximately a few ion Larmor radii. An electric field is normal to the magnetic field in the sheath. Solutions of Vlasov's equation and Maxwell's equations are presented which account for several types of magnetic holes, including 'null sheets,' that have been observed.

  2. Black Holes and Firewalls

    NASA Astrophysics Data System (ADS)

    Polchinski, Joseph

    2015-04-01

    Our modern understanding of space, time, matter, and even reality itself arose from the three great revolutions of the early twentieth century: special relativity, general relativity, and quantum mechanics. But a century later, this work is unfinished. Many deep connections have been discovered, but the full form of a unified theory incorporating all three principles is not known. Thought experiments and paradoxes have often played a key role in figuring out how to fit theories together. For the unification of general relativity and quantum mechanics, black holes have been an important arena. I will talk about the quantum mechanics of black holes, the information paradox, and the latest version of this paradox, the firewall. The firewall points to a conflict between our current theories of spacetime and of quantum mechanics. It may lead to a new understanding of how these are connected, perhaps based on quantum entanglement.

  3. Effects of cosmic acceleration on black hole thermodynamics

    NASA Astrophysics Data System (ADS)

    Mandal, Abhijit; Biswas, Ritabrata

    2015-05-01

    Direct local impacts of cosmic acceleration upon a black hole are matters of interest. Babichev et al. had published before that the Friedmann equations which are prevailing the part of fluid filled up in the universe to lead (or to be very specific, `dominate') the other constituents of universe and are forcing the universe to undergo present-day accelerating phase (or to lead to violate the strong energy condition and latter the week energy condition), will themselves tell that the rate of change of mass of the central black hole due to such exotic fluid's accretion will essentially shrink the mass of the black hole. But this is a global impact indeed. The local changes in the space time geometry next to the black hole can be analysed from a modified metric governing the surrounding space time of a black hole. A charged de Sitter black hole solution encircled by quintessence field is chosen for this purpose. Different thermodynamic quantities are analysed for different values of quintessence equation of state parameter, ω q . Specific jumps in the nature of the thermodynamic space near to the quintessence or phantom barrier are noted and physically interpreted as far as possible. Nature of phase transitions and the situations at which these transitions are taking place are also explored. It is determined that before quintessence starts to work () it was preferable to have a small unstable black hole followed by a large stable one. But in quintessence (), black holes are destined to be unstable large ones pre-quelled by stable/unstable small/intermediate mass black holes.

  4. Effects of cosmic acceleration on black hole thermodynamics

    NASA Astrophysics Data System (ADS)

    Mandal, Abhijit

    2016-07-01

    Direct local impacts of cosmic acceleration upon a black hole are matters of interest. Babichev et. al. had published before that the Friedmann equations which are prevailing the part of fluid filled up in the universe to lead (or to be very specific, `dominate') the other constituents of universe and are forcing the universe to undergo present-day accelerating phase (or to lead to violate the strong energy condition and latter the week energy condition), will themselves tell that the rate of change of mass of the central black hole due to such exotic fluid's accretion will essentially shrink the mass of the black hole. But this is a global impact indeed. The local changes in the space time geometry next to the black hole can be analysed from a modified metric governing the surrounding space time of a black hole. A charged deSitter black hole solution encircled by quintessence field is chosen for this purpose. Different thermodynamic parameters are analysed for different values of quintessence equation of state parameter, ω_q. Specific jumps in the nature of the thermodynamic space near to the quintessence or phantom barrier are noted and physically interpreted as far as possible. Nature of phase transitions and the situations at which these transitions are taking place are also explored. It is determined that before quintessence starts to work (ω_q=-0.33>-1/3) it was preferable to have a small unstable black hole followed by a large stable one. But in quintessence (-1/3>ω_q>-1), black holes are destined to be unstable large ones pre-quelled by stable/ unstable small/ intermediate mass black holes.

  5. Deformations of anti-de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Detournay, Stephane

    2006-11-01

    This PhD thesis mainly deals with deformations of locally anti-de Sitter black holes, focusing in particular on BTZ black holes. We first study the generic rotating and (extended) non-rotating BTZ black holes within a pseudo-Riemannian symmetric spaces framework, emphasize on the role played by solvable subgroups of SL(2,R) in the black hole structure and derive their global geometry in a group-theoretical way. We analyse how these observations are transposed in the case of higher-dimensional locally AdS black holes. We then show that there exists, in SL(2,R), a family of twisted conjugacy classes which give rise to winding symmetric WZW D1-branes in a BTZ black hole background. The term "deformation" is then considered in two distinct ways. On the one hand, we deform the algebra of functions on the branes in the sense of (strict) deformation quantization, giving rise to a "noncommutative black hole". In the same context, we investigate the question of invariant deformations of the hyperbolic plane and present explicit formulae. On the other hand, we explore the moduli space of the (orbifolded) SL(2,R) WZW model by studying its marginal deformations, yielding namely a new class of exact black string solutions in string theory. These deformations also allow us to relate the D1-branes in BTZ black holes to D0-branes in the 2D black hole. A fair proportion of this thesis consists of (hopefully) pedagogical short introductions to various subjects: deformation quantization, string theory, WZW models, symmetric spaces, symplectic and Poisson geometry.

  6. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.

    1988-01-01

    Processes that may be responsible for the thinning in the ozone layer above the South Pole are described. The chlorine catalytic cycle which destroys ozone is described, as are the major types of reactions that are believed to interfere with this cycle by forming chlorine reservoirs. The suspected contributions of polar stratospheric clouds to these processes are examined. Finally, the possibility that the ozone hole may be due more to a shift in atmospheric dynamics than to chemical destruction is addressed.

  7. BLACK HOLE AURORA POWERED BY A ROTATING BLACK HOLE

    SciTech Connect

    Takahashi, Masaaki; Takahashi, Rohta

    2010-05-15

    We present a model for high-energy emission sources generated by a standing magnetohydrodynamical (MHD) shock in a black hole magnetosphere. The black hole magnetosphere would be constructed around a black hole with an accretion disk, where a global magnetic field could be originated by currents in the accretion disk and its corona. Such a black hole magnetosphere may be considered as a model for the central engine of active galactic nuclei, some compact X-ray sources, and gamma-ray bursts. The energy sources of the emission from the magnetosphere are the gravitational and electromagnetic energies of magnetized accreting matters and the rotational energy of a rotating black hole. When the MHD shock generates in MHD accretion flows onto the black hole, the plasma's kinetic energy and the black hole's rotational energy can convert to radiative energy. In this Letter, we demonstrate the huge energy output at the shock front by showing negative energy postshock accreting MHD flows for a rapidly rotating black hole. This means that the extracted energy from the black hole can convert to the radiative energy at the MHD shock front. When an axisymmetric shock front is formed, we expect a ring-shaped region with very hot plasma near the black hole; this would look like an 'aurora'. The high-energy radiation generated from there would carry to us the information for the curved spacetime due to the strong gravity.

  8. Perspectives: Black Holes

    NASA Technical Reports Server (NTRS)

    Dolan, Joseph F.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    When asked to discuss Cyg XR-1, E. E. Salpeter once concluded, 'A black hole in Cyg X(R)-1 is the most conservative hypothesis.' Recent observations now make it likely that a black hole in Cyg XR-1 is the only hypothesis tenable. Chandrasekhar first showed that compact stars - those with the inward force of gravity on their outer layers balanced by the pressure generated by the Pauli exclusion principle acting on its electrons (in white dwarfs) or nucleons (in neutron stars) - have a maximum mass. Equilibrium is achieved at a minimum of the total energy of the star, which is the sum of the positive Fermi energy and the negative gravitational energy. The maximum mass attainable in equilibrium is found by setting E = 0: M(max) = 1.5 M(Sun). If the mass of the star is larger than this, then E can be decreased without bound by decreasing the star's radius and increasing its (negative) gravitational energy. No equilibrium value of the radius exist, and general relativity predicts that gravitational collapse to a point occurs. This point singularity is a black hole.

  9. Accretion onto the first stellar mass black holes

    SciTech Connect

    Alvarez, Marcelo A.; Wise, John H.; Abel, Tom

    2009-08-05

    The first stars, forming at redshifts z > 15 in minihalos with M {approx} 10{sup 5-6} M{sub {circle_dot}} may leave behind remnant black holes, which could conceivably have been the 'seeds' for the supermassive black holes observed at z {approx}< 7. We study remnant black hole growth through accretion, including for the first time the radiation emitted due to accretion, with adaptive mesh refinement cosmological radiation-hydrodynamical simulations. The effects of photo-ionization and heating dramatically affect the large-scale inflow, resulting in negligible mass growth. We compare cases with accretion luminosity included and neglected to show that accretion radiation drastically changes the environment within 100 pc of the black hole, increasing gas temperatures by an order of magnitude. Gas densities are reduced and further star formation in the same minihalo is prevented for the two hundred million years we followed. Without radiative feedback included most seed black holes do not gain mass as efficiently as has been hoped for in previous theories, implying that black hole remnants of Pop III stars in minihalos are not likely to be miniquasars. Most importantly, however, our calculations demonstrate that if these black holes are indeed accreting close to the Bondi-Hoyle rate with ten percent radiative efficiency they have a dramatic local effect in regulating star formation in the first galaxies. This suggests a novel mechanism for massive black hole formation - stellar-mass black holes may have suppressed fragmentation and star formation after falling into halos with virial temperatures {approx} 10{sup 4} K, facilitating intermediate mass black hole formation at their centers.

  10. ACCRETION ONTO THE FIRST STELLAR-MASS BLACK HOLES

    SciTech Connect

    Alvarez, Marcelo A.; Abel, Tom Wise, John H

    2009-08-20

    The first stars, forming at redshifts z > 15 in minihalos with M {approx} 10{sup 5-6} M {sub sun} may leave behind remnant black holes, which could conceivably have been the 'seeds' for the supermassive black holes observed at z {approx}< 7. We study remnant black hole growth through accretion, including for the first time the radiation emitted due to accretion, with adaptive mesh refinement cosmological radiation-hydrodynamical simulations. The effects of photoionization and heating dramatically affect the large-scale inflow, resulting in negligible mass growth. We compare cases with accretion luminosity included and neglected to show that accretion radiation drastically changes the environment within 100 pc of the black hole, increasing gas temperatures by an order of magnitude. Gas densities are reduced and further star formation in the same minihalo is prevented for the 200 million years we followed. Without radiative feedback included most seed black holes do not gain mass as efficiently as has been hoped for in previous theories, implying that black hole remnants of population III stars in minihalos are not likely to be miniquasars. Most importantly, however, our calculations demonstrate that if these black holes are indeed accreting close to the Bondi-Hoyle rate with 10% radiative efficiency they have a dramatic local effect in regulating star formation in the first galaxies. This suggests a novel mechanism for massive black hole formation-stellar-mass black holes may have suppressed fragmentation and star formation after falling into halos with virial temperatures {approx}10{sup 4} K, facilitating massive black hole formation at their centers.

  11. A spectral-Lagrangian Boltzmann solver for a multi-energy level gas

    SciTech Connect

    Munafò, Alessandro; Haack, Jeffrey R.; Gamba, Irene M.; Magin, Thierry E.

    2014-05-01

    In this paper a spectral-Lagrangian method is proposed for the full, non-linear Boltzmann equation for a multi-energy level gas typical of a hypersonic re-entry flow. Internal energy levels are treated as separate species and inelastic collisions (leading to internal energy excitation and relaxation) are accounted for. The formulation developed can also be used for the case of a gas mixture made of monatomic gases without internal energy (where only elastic collisions occur). The advantage of the spectral-Lagrangian method lies in the generality of the algorithm in use for the evaluation of the elastic and inelastic collision operators, as well as the conservation of mass, momentum and energy during collisions. The latter is realized through the solution of constrained optimization problems. The computational procedure is based on the Fourier transform of the partial elastic and inelastic collision operators and exploits the fact that these can be written as weighted convolutions in Fourier space with no restriction on the cross-section model. The feasibility of the proposed approach is demonstrated through numerical examples for both space homogeneous and in-homogeneous problems. Computational results are compared with those obtained by means of the DSMC method in order to assess the accuracy of the proposed spectral-Lagrangian method.

  12. Energy levels, radiative rates, and lifetimes for transitions in W LVIII

    SciTech Connect

    Aggarwal, Kanti M. Keenan, Francis P.

    2014-11-15

    Energy levels and radiative rates are reported for transitions in Cl-like W LVIII. Configuration interaction (CI) has been included among 44 configurations (generating 4978 levels) over a wide energy range up to 363 Ryd, and the general-purpose relativistic atomic structure package (GRASP) adopted for the calculations. Since no other results of comparable complexity are available, calculations have also been performed with the flexible atomic code (FAC), which help in assessing the accuracy of our results. Energies are listed for the lowest 400 levels (with energies up to ∼98 Ryd), which mainly belong to the 3s{sup 2}3p{sup 5}, 3s3p{sup 6}, 3s{sup 2}3p{sup 4}3d, 3s{sup 2}3p{sup 3}3d{sup 2}, 3s3p{sup 4}3d{sup 2}, 3s{sup 2}3p{sup 2}3d{sup 3}, and 3p{sup 6}3d configurations, and radiative rates are provided for four types of transitions, i.e. E1, E2, M1, and M2. Our energy levels are assessed to be accurate to better than 0.5%, whereas radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions.

  13. Origin of the energy level alignment at organic/organic interfaces: The role of structural defects

    NASA Astrophysics Data System (ADS)

    Bussolotti, Fabio; Yang, Jinpeng; Hinderhofer, Alexander; Huang, Yuli; Chen, Wei; Kera, Satoshi; Wee, Andrew T. S.; Ueno, Nobuo

    2014-03-01

    In this paper, the electronic properties of as-deposited and N2-exposedCuPc/F16CuPc interface, a prototype system for organic photovoltaic applications, are investigated by using ultralow background, high-sensitivity photoemission spectroscopy. It is found that (i) N2 exposure significantly modifies the energy level alignment (ELA) at the interface between CuPc and F16CuPc layer and (ii) the direction of the N2-induced energy level shift of the CuPc depends on the position of the Fermi level (EF) in the CuPc highest occupied molecular orbital-lowest unoccupied molecular orbital gap of the as-deposited film. These observations are related to the changes in the density of gap states (DOGS) produced by structural imperfections in the molecular packing geometry, as introduced by the N2 penetration into the CuPc layer. This result demonstrates the key role of structure-induced DOGS in controlling the ELA at organic/organic interfaces.

  14. Energy level alignment at hybridized organic-metal interfaces from a GW projection approach

    NASA Astrophysics Data System (ADS)

    Chen, Yifeng; Tamblyn, Isaac; Quek, Su Ying

    Energy level alignments at organic-metal interfaces are of profound importance in numerous (opto)electronic applications. Standard density functional theory (DFT) calculations generally give incorrect energy level alignments and missing long-range polarization effects. Previous efforts to address this problem using the many-electron GW method have focused on physisorbed systems where hybridization effects are insignificant. Here, we use state-of-the-art GW methods to predict the level alignment at the amine-Au interface, where molecular levels do hybridize with metallic states. This non-trivial hybridization implies that DFT result is a poor approximation to the quasiparticle states. However, we find that the self-energy operator is approximately diagonal in the molecular basis, allowing us to use a projection approach to predict the level alignments. Our results indicate that the metallic substrate reduces the HOMO-LUMO gap by 3.5 4.0 eV, depending on the molecular coverage/presence of Au adatoms. Our GW results are further compared with those of a simple image charge model that describes the level alignment in physisorbed systems. Syq and YC acknowledge Grant NRF-NRFF2013-07 and the medium-sized centre program from the National Research Foundation, Singapore.

  15. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives

    NASA Astrophysics Data System (ADS)

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L = cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF = N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu3 + in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu3 + ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of 5D0 and triplet state contracts.

  16. Spectrum and energy levels of five-times ionized zirconium (Zr VI)

    NASA Astrophysics Data System (ADS)

    Reader, Joseph; Lindsay, Mark D.

    2016-02-01

    We carried out a new analysis of the spectrum of five-times-ionized zirconium Zr VI. For this we used sliding-spark discharges together with normal- and grazing-incidence spectrographs to observe the spectrum from 160 to 2000 Å. These observations showed that the analysis of this spectrum by Khan et al (1985 Phys. Scr. 31 837) contained a significant number of incorrect energy levels. We have now classified ˜420 lines as transitions between 23 even-parity levels 73 odd-parity levels. The 4s24p5, 4s4p6, 4s24p44d, 5s, 5d, 6s configurations are now complete, although a few levels of 4s24p45d are tentative. We determined Ritz-type wavelengths for ˜135 lines from the optimized energy levels. The uncertainties range from 0.0003 to 0.0020 Å. Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels were used to interpret the observed configurations. Oscillator strengths for all classified lines were calculated with the fitted parameters. The results are compared with values for the level energies, percentage compositions, and transition probabilities from recent ab initio theoretical calculations. The ionization energy was revised to 777 380 ± 300 cm-1 (96.38 ± 0.04 eV).

  17. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives.

    PubMed

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L=cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF=N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu(3+) in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu(3+) ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of (5)D0 and triplet state contracts.

  18. A new classification of the amino acid side chains based on doublet acceptor energy levels.

    PubMed Central

    Sneddon, S F; Morgan, R S; Brooks, C L

    1988-01-01

    We describe a new classification of the amino acid side chains based on the potential energy level at which each will accept an extra (doublet) electron. The doublet acceptor energy level, and the doublet acceptor orbital were calculated using semiempirical INDO/2-UHF molecular orbital theory. The results of these calculations show that the side chains fall into four groups. We have termed these groups repulsive, insulating, semiconducting, and attractive in accordance with where each lies on the relative energy scale. We use this classification to examine the role of residues between the donor and acceptor in modulating the rate and mechanism of electron transfer in proteins. With the calculated acceptor levels, we construct a potential barrier for those residues between the donor and acceptor. It is the area beneath this barrier that determines the decay of electronic coupling between donor and acceptor, and thus the transfer rate. We have used this schematic approach to characterize the four electron transfer pathways in myoglobin recently studied by Mayo et al. (Mayo, S.L., W.R. Ellis, R.J. Crutchley, and H.B. Gray. 1986. Science [Wash. DC]. 233:948-952). PMID:3342271

  19. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives.

    PubMed

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L=cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF=N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu(3+) in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu(3+) ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of (5)D0 and triplet state contracts. PMID:26802538

  20. The molecular potential energy surface and vibrational energy levels of methyl fluoride. Part II.

    PubMed

    Manson, Steven A; Law, Mark M; Atkinson, Ian A; Thomson, Grant A

    2006-06-28

    New analytical bending and stretching, ground electronic state, potential energy surfaces for CH(3)F are reported. The surfaces are expressed in bond-length, bond-angle internal coordinates. The four-dimensional stretching surface is an accurate, least squares fit to over 2000 symmetrically unique ab initio points calculated at the CCSD(T) level. Similarly, the five-dimensional bending surface is a fit to over 1200 symmetrically unique ab initio points. This is an important first stage towards a full nine-dimensional potential energy surface for the prototype CH(3)F molecule. Using these surfaces, highly excited stretching and (separately) bending vibrational energy levels of CH(3)F are calculated variationally using a finite basis representation method. The method uses the exact vibrational kinetic energy operator derived for XY(3)Z systems by Manson and Law (preceding paper, Part I, Phys. Chem. Chem. Phys., 2006, 8, DOI: 10.1039/b603106d). We use the full C(3v) symmetry and the computer codes are designed to use an arbitrary potential energy function. Ultimately, these results will be used to design a compact basis for fully coupled stretch-bend calculations of the vibrational energy levels of the CH(3)F system.

  1. THE SPECTRUM OF THORIUM FROM 250 nm TO 5500 nm: RITZ WAVELENGTHS AND OPTIMIZED ENERGY LEVELS

    SciTech Connect

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm{sup –1} to 1800 cm{sup –1}). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer and Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis and Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  2. Ideal Energy-Level Alignment at the ZnO/P3HT Photovoltaic Interface

    NASA Astrophysics Data System (ADS)

    Noori, Keian; Giustino, Feliciano

    2013-03-01

    Despite the significant progress made during the past decade, hybrid organic-inorganic photovoltaic devices comprising P3HT and ZnO still suffer from low short-circuit currents and moderate open-circuit voltages. These barriers call for a detailed examination of the atomic-scale physics underlying the energy-level alignment at the ZnO/P3HT interface, which is of critical importance if we are to understand what is the maximum ideal open-circuit voltage for this class of solar cell. Here we present the results of a first-principles study on large model interfaces between ZnO and P3HT. Using a combination of density-functional theory (DFT) and post-DFT methods based on hybrid functionals, we analyze the atomic structure and energetics of the semiconductor/polymer interface, as well as the interfacial energy-level alignment. We explore the effect of charge transfer on the ideal open-circuit voltage and identify a failure in the standard electron affinity rule. We determine a maximum ideal open-circuit voltage of ~2 V, which suggests that there is significant room for enhancing the performance of ZnO/P3HT solar cells by optimizing the interface at the nanoscale. This work is supported by the ERC under the EU FP7 / ERC grant no. 239578. Calculations were performed in part at the Oxford Supercomputing Centre.

  3. Efficient light emission from inorganic and organic semiconductor hybrid structures by energy-level tuning

    PubMed Central

    Schlesinger, R.; Bianchi, F.; Blumstengel, S.; Christodoulou, C.; Ovsyannikov, R.; Kobin, B.; Moudgil, K.; Barlow, S.; Hecht, S.; Marder, S.R.; Henneberger, F.; Koch, N.

    2015-01-01

    The fundamental limits of inorganic semiconductors for light emitting applications, such as holographic displays, biomedical imaging and ultrafast data processing and communication, might be overcome by hybridization with their organic counterparts, which feature enhanced frequency response and colour range. Innovative hybrid inorganic/organic structures exploit efficient electrical injection and high excitation density of inorganic semiconductors and subsequent energy transfer to the organic semiconductor, provided that the radiative emission yield is high. An inherent obstacle to that end is the unfavourable energy level offset at hybrid inorganic/organic structures, which rather facilitates charge transfer that quenches light emission. Here, we introduce a technologically relevant method to optimize the hybrid structure's energy levels, here comprising ZnO and a tailored ladder-type oligophenylene. The ZnO work function is substantially lowered with an organometallic donor monolayer, aligning the frontier levels of the inorganic and organic semiconductors. This increases the hybrid structure's radiative emission yield sevenfold, validating the relevance of our approach. PMID:25872919

  4. Black Hole Unitarity and Antipodal Entanglement

    NASA Astrophysics Data System (ADS)

    't Hooft, Gerard

    2016-09-01

    Hawking particles emitted by a black hole are usually found to have thermal spectra, if not exactly, then by a very good approximation. Here, we argue differently. It was discovered that spherical partial waves of in-going and out-going matter can be described by unitary evolution operators independently, which allows for studies of space-time properties that were not possible before. Unitarity dictates space-time, as seen by a distant observer, to be topologically non-trivial. Consequently, Hawking particles are only locally thermal, but globally not: we explain why Hawking particles emerging from one hemisphere of a black hole must be 100 % entangled with the Hawking particles emerging from the other hemisphere. This produces exclusively pure quantum states evolving in a unitary manner, and removes the interior region for the outside observer, while it still completely agrees locally with the laws of general relativity. Unitarity is a starting point; no other assumptions are made. Region I and the diametrically opposite region II of the Penrose diagram represent antipodal points in a PT or CPT relation, as was suggested before. On the horizon itself, antipodal points are identified. A candidate instanton is proposed to describe the formation and evaporation of virtual black holes of the type described here.

  5. Black Hole Unitarity and Antipodal Entanglement

    NASA Astrophysics Data System (ADS)

    't Hooft, Gerard

    2016-05-01

    Hawking particles emitted by a black hole are usually found to have thermal spectra, if not exactly, then by a very good approximation. Here, we argue differently. It was discovered that spherical partial waves of in-going and out-going matter can be described by unitary evolution operators independently, which allows for studies of space-time properties that were not possible before. Unitarity dictates space-time, as seen by a distant observer, to be topologically non-trivial. Consequently, Hawking particles are only locally thermal, but globally not: we explain why Hawking particles emerging from one hemisphere of a black hole must be 100 % entangled with the Hawking particles emerging from the other hemisphere. This produces exclusively pure quantum states evolving in a unitary manner, and removes the interior region for the outside observer, while it still completely agrees locally with the laws of general relativity. Unitarity is a starting point; no other assumptions are made. Region I and the diametrically opposite region II of the Penrose diagram represent antipodal points in a PT or CPT relation, as was suggested before. On the horizon itself, antipodal points are identified. A candidate instanton is proposed to describe the formation and evaporation of virtual black holes of the type described here.

  6. Oxidative Chemical Vapor Deposition of Neutral Hole Transporting Polymer for Enhanced Solar Cell Efficiency and Lifetime.

    PubMed

    Jo, Won Jun; Nelson, Justin T; Chang, Sehoon; Bulović, Vladimir; Gradečak, Silvija; Strano, Michael S; Gleason, Karen K

    2016-08-01

    The concept of a neutral hole-transporting polymer is realized for the first time, by integrating patterned Cl(-) -doped poly(3,4-dimethoxythiophene) thin films into organic solar cells through a vacuum-based polymer vapor printing technique. Due to this novel polymer's neutrality, high transparency, good conductivity, and appropriate energy levels, the solar-cell efficiency and lifetime are significantly enhanced. PMID:27167214

  7. Band-Tail Transport of CuSCN: Origin of Hole Extraction Enhancement in Organic Photovoltaics.

    PubMed

    Kim, Minju; Park, Soohyung; Jeong, Junkyeong; Shin, Dongguen; Kim, Jimin; Ryu, Sae Hee; Kim, Keun Su; Lee, Hyunbok; Yi, Yeonjin

    2016-07-21

    Copper thiocyanate (CuSCN) is known as a promising hole transport layer in organic photovoltaics (OPVs) due to its good hole conduction and exciton blocking abilities with high transparency. Despite its successful device applications, the origin of its hole extraction enhancement in OPVs has not yet been understood. Here, we investigated the electronic structure of CuSCN and the energy level alignment at the poly(3-hexylthiophene-2,5-diyl) (P3HT)/CuSCN/ITO interfaces using ultraviolet photoelectron spectroscopy. The band-tail states of CuSCN close to the Fermi level (EF) were observed at 0.25 eV below the EF, leading to good hole transport. The CuSCN interlayer significantly reduces the hole transport barrier between ITO and P3HT due to its high work function and band-tail states. The barrier reduction leads to enhanced current density-voltage characteristics of hole-dominated devices. These results provide the origin of hole-extraction enhancement by CuSCN and insights for further application.

  8. Ferromagnetic Clouds Caused by Hole Motion in a One-Dimensional t-J Model

    NASA Astrophysics Data System (ADS)

    Sano, Kazuhiro; Takano, Ken'ichi

    2016-09-01

    The one-dimensional t1-t2-J1-J2 model is examined in the one-hole and two-hole cases. The ground-state phase diagram of the one-hole case includes a series of partial ferromagnetic phases, which are stacked in a regime of positive and small J1. The ground state in each of these partial ferromagnetic phases includes a ferromagnetic cloud, which is a multiple-spin bound state together with the hole. The ferromagnetic cloud is a large magnetic polaron with a heavy mass in a single-band electronic system and is considered to form as a result of Nagaoka ferromagnetism, which locally acts around the hole. Results for the two-hole case suggest the existence of a liquid of ferromagnetic clouds at a finite hole density.

  9. Hall scrambling on black hole horizons

    NASA Astrophysics Data System (ADS)

    Fischler, Willy; Kundu, Sandipan

    2015-08-01

    We explore the effect of the electrodynamics θ angle on the macroscopic properties of black hole horizons. Using only classical Einstein-Maxwell-Chern-Simons theory in (3 +1 ) dimensions, in the form of the membrane paradigm, we show that in the presence of the θ term, a black hole horizon behaves as a Hall conductor, for an observer hovering outside. We study how localized perturbations created on the stretched horizon scramble on the horizon by dropping a charged particle. We show that the θ angle affects the way perturbations scramble on the horizon, in particular, it introduces vortices without changing the scrambling time. This Hall scrambling of information is also expected to occur on cosmological horizons.

  10. Geology of the Devils Hole area, Nevada

    USGS Publications Warehouse

    Carr, W.J.

    1988-01-01

    Detailed and reconnaissance mapping of the Devils Hole, Nevada, area has improved definition of the local geologic structure within a regional carbonate aquifer near its primary discharge points -- the springs of Ash Meadows. Several formerly unmapped calcite veins, and other young calcite-lined paleo-spring feeder zones were found, as well as a number of previously unknown small collapse areas in the limestone. Although the predominant structural grain of the area is oriented northwest, the importance of the very subordinate northeast-striking faults and fractures is underscored by their association with Devils Hole itself, with most of the collapse depressions, and with many of the calcite veins in ' lake beds ' and alluvium. Probable channeling of groundwater flow may occur along one important northeast-striking fault zone. The persistent tendency for openings may have been facilitated by underlying low-angle faults that separate brittle carbonate rocks from underlying, less-competent clastic rocks. (Author 's abstract)

  11. Semiclassical geons as solitonic black hole remnants

    SciTech Connect

    Lobo, Francisco S.N.; Olmo, Gonzalo J.; Rubiera-Garcia, D. E-mail: gonzalo.olmo@csic.es

    2013-07-01

    We find that the end state of black hole evaporation could be represented by non-singular and without event horizon stable solitonic remnants with masses of the order the Planck scale and up to ∼ 16 units of charge. Though these objects are locally indistinguishable from spherically symmetric, massive electric (or magnetic) charges, they turn out to be sourceless geons containing a wormhole generated by the electromagnetic field. Our results are obtained by interpreting semiclassical corrections to Einstein's theory in the first-order (Palatini) formalism, which yields second-order equations and avoids the instabilities of the usual (metric) formulation of quadratic gravity. We also discuss the potential relevance of these solutions for primordial black holes and the dark matter problem.

  12. Black hole evaporation with separated fermions.

    PubMed

    Han, Tao; Kribs, Graham D; McElrath, Bob

    2003-01-24

    In models with a low quantum gravity scale, fast proton decay can be avoided by localizing quarks and leptons to separated positions in an extra 1/TeV sized dimension with gauge and Higgs fields living throughout. Black holes with masses of the order of the quantum gravity scale are therefore expected to evaporate nonuniversally, preferentially radiating directly into quarks or leptons but not both. Should black holes be copiously produced at a future hadron collider, we find the ratio of final state jets to charged leptons to photons is 113:8:1, which differs from previous analyses that assumed all standard model fields live at the same point in the extra dimensional space.

  13. What drives the growth of black holes?

    NASA Astrophysics Data System (ADS)

    Alexander, D. M.; Hickox, R. C.

    2012-06-01

    Massive black holes (BHs) are at once exotic and yet ubiquitous, residing at the centers of massive galaxies in the local Universe. Recent years have seen remarkable advances in our understanding of how these BHs form and grow over cosmic time, during which they are revealed as Active Galactic Nuclei (AGN). However, despite decades of research, we still lack a coherent picture of the physical drivers of BH growth, the connection between the growth of BHs and their host galaxies, the role of large-scale environment on the fueling of BHs, and the impact of BH-driven outflows on the growth of galaxies. In this paper we review our progress in addressing these key issues, motivated by the science presented at the "What drives the growth of black holes?" workshop held at Durham on 26-29th July 2010, and discuss how these questions may be tackled with current and future facilities.

  14. Black-hole universe: time evolution.

    PubMed

    Yoo, Chul-Moon; Okawa, Hirotada; Nakao, Ken-ichi

    2013-10-18

    Time evolution of a black hole lattice toy model universe is simulated. The vacuum Einstein equations in a cubic box with a black hole at the origin are numerically solved with periodic boundary conditions on all pairs of faces opposite to each other. Defining effective scale factors by using the area of a surface and the length of an edge of the cubic box, we compare them with that in the Einstein-de Sitter universe. It is found that the behavior of the effective scale factors is well approximated by that in the Einstein-de Sitter universe. In our model, if the box size is sufficiently larger than the horizon radius, local inhomogeneities do not significantly affect the global expansion law of the Universe even though the inhomogeneity is extremely nonlinear.

  15. Acoustic black holes: recent developments in the theory and applications.

    PubMed

    Krylov, Victor

    2014-08-01

    Acoustic black holes are relatively new physical objects that have been introduced and investigated mainly during the last decade. They can absorb almost 100% of the incident wave energy, and this makes them very attractive for such traditional engineering applications as vibration damping in different engineering structures and sound absorption in gases and liquids. They also could be useful for some ultrasonic devices using Lamb wave propagation to provide anechoic termination for such waves. So far, acoustic black holes have been investigated mainly for flexural waves in thin plates, for which the required gradual changes in local wave velocity with distance can be easily achieved by changing the plates' local thickness. The present paper provides a brief review of the theory of acoustic black holes, including their comparison with optic black holes introduced about five years ago. Review is also given of the recent experimental work carried out at Loughborough University on damping structural vibrations using the acoustic black hole effect. This is followed by the discussion on potential applications of the acoustic black hole effect for sound absorption in air.

  16. Acoustic black holes: recent developments in the theory and applications.

    PubMed

    Krylov, Victor

    2014-08-01

    Acoustic black holes are relatively new physical objects that have been introduced and investigated mainly during the last decade. They can absorb almost 100% of the incident wave energy, and this makes them very attractive for such traditional engineering applications as vibration damping in different engineering structures and sound absorption in gases and liquids. They also could be useful for some ultrasonic devices using Lamb wave propagation to provide anechoic termination for such waves. So far, acoustic black holes have been investigated mainly for flexural waves in thin plates, for which the required gradual changes in local wave velocity with distance can be easily achieved by changing the plates' local thickness. The present paper provides a brief review of the theory of acoustic black holes, including their comparison with optic black holes introduced about five years ago. Review is also given of the recent experimental work carried out at Loughborough University on damping structural vibrations using the acoustic black hole effect. This is followed by the discussion on potential applications of the acoustic black hole effect for sound absorption in air. PMID:25073137

  17. Black Holes, Worm Holes, and Future Space Propulsion

    NASA Technical Reports Server (NTRS)

    Barret, Chris

    2000-01-01

    NASA has begun examining the technologies needed for an Interstellar Mission. In 1998, a NASA Interstellar Mission Workshop was held at the California Institute of Technology to examine the technologies required. Since then, a spectrum of research efforts to support such a mission has been underway, including many advanced and futuristic space propulsion concepts which are being explored. The study of black holes and wormholes may provide some of the breakthrough physics needed to travel to the stars. The first black hole, CYGXI, was discovered in 1972 in the constellation Cygnus X-1. In 1993, a black hole was found in the center of our Milky Way Galaxy. In 1994, the black hole GRO J1655-40 was discovered by the NASA Marshall Space Flight center using the Gamma Ray Observatory. Today, we believe we have found evidence to support the existence of 19 black holes, but our universe may contain several thousands. This paper discusses the dead star states - - both stable and unstable, white dwarfs, neutron stars, pulsars, quasars, the basic features and types of black holes: nonspinning, nonspinning with charge, spinning, and Hawking's mini black holes. The search for black holes, gravitational waves, and Laser Interferometer Gravitational Wave Observatory (LIGO) are reviewed. Finally, concepts of black hole powered space vehicles and wormhole concepts for rapid interstellar travel are discussed in relation to the NASA Interstellar Mission.

  18. Stability of Black Holes and Black Branes

    NASA Astrophysics Data System (ADS)

    Hollands, Stefan; Wald, Robert M.

    2013-08-01

    We establish a new criterion for the dynamical stability of black holes in D ≥ 4 spacetime dimensions in general relativity with respect to axisymmetric perturbations: Dynamical stability is equivalent to the positivity of the canonical energy, {{E}}, on a subspace, {{T}}, of linearized solutions that have vanishing linearized ADM mass, momentum, and angular momentum at infinity and satisfy certain gauge conditions at the horizon. This is shown by proving that—apart from pure gauge perturbations and perturbations towards other stationary black holes—{{E}} is nondegenerate on {{T}} and that, for axisymmetric perturbations, {{E}} has positive flux properties at both infinity and the horizon. We further show that {{E}} is related to the second order variations of mass, angular momentum, and horizon area by {{E} = δ^2 M -sum_A Ω_A δ^2 J_A - κ/8πδ^2 A}, thereby establishing a close connection between dynamical stability and thermodynamic stability. Thermodynamic instability of a family of black holes need not imply dynamical instability because the perturbations towards other members of the family will not, in general, have vanishing linearized ADM mass and/or angular momentum. However, we prove that for any black brane corresponding to a thermodynamically unstable black hole, sufficiently long wavelength perturbations can be found with {{E} < 0} and vanishing linearized ADM quantities. Thus, all black branes corresponding to thermodynmically unstable black holes are dynamically unstable, as conjectured by Gubser and Mitra. We also prove that positivity of {{E}} on {{T}} is equivalent to the satisfaction of a " local Penrose inequality," thus showing that satisfaction of this local Penrose inequality is necessary and sufficient for dynamical stability. Although we restrict our considerations in this paper to vacuum general relativity, most of the results of this paper are derived using general Lagrangian and Hamiltonian methods and therefore can be

  19. Energy level decay and excited state absorption processes in erbium-doped tellurite glass

    NASA Astrophysics Data System (ADS)

    Gomes, Laércio; Oermann, Michael; Ebendorff-Heidepriem, Heike; Ottaway, David; Monro, Tanya; Felipe Henriques Librantz, André; Jackson, Stuart D.

    2011-10-01

    The fundamental excited state decay processes relating to the 4I11/2 → 4I13/2 transition in singly Er3+-doped tellurite (TZNL) glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the 4I11/2 energy level at 970 nm and selective laser excitation of the 4I13/2 energy level at 1485 nm has established that energy transfer upconversion by way of a dipole-dipole interaction between two excited erbium ions in the 4I13/2 level populates the 4I11/2 upper laser level of the 3 μm transition. This upconversion has been analyzed for Er2O3 concentrations between 0.5 mol. % and 2.2 mol. %. The 4I13/2 and 4I11/2 energy levels emit luminescence with peaks located at 1532 nm and 2734 nm, respectively, with radiative decay efficiencies of 65% and 6.8% for the higher (2.2 mol. %) concentration sample. The low 2.7 μm emission efficiency is due to the non-radiative decay bridging the 4I11/2 → 4I13/2 transition and energy transfer to the OH- groups in the glass. Excited state absorption was observed to occur from the 4I13/2 and 4I11/2 levels with peak absorptions occurring at 1550 nm and 971 nm, respectively. The decay time of the 4I11/2 excited state decreased with an increase in the Er3+ concentration, which related to energy transfer to OH- ions that had a measured concentration of 6.6 × 1018 cm-3. Results from numerical simulations showed that a population inversion is reached at a threshold pumping intensity of ˜80 kW cm-2 for a cw laser pump at 976 nm if [Er3+] ≥ 1.2 × 1021 cm-3 (or [Er2O3] ≥ 2.65 mol. %) without OH- impurities being present.

  20. The First Black Holes

    NASA Astrophysics Data System (ADS)

    Abel, T.

    star. Within this wide range of possible initial masses the death of these star will lead very different remnants (Heger and Woosley 2001). In the case of stars with masses larger than 260 solar mass no metals may be released in black holes are the natural outcome. This may be an interesting possibility to form intermediate mass black holes which are attractive seeds to be nurtured to the super-massive black holes observed in the centers of nearby galaxies. However, no metals would be released and it would prove difficult to understand the transition to the formation of low mass metal enriched population II stars. Stars with masses below 140 solar masses would enrich the intergalactic medium as well as form massive black holes. The coincidence of the Kelvin Helmholtz time with our computed accretion times at about 120 solar masses may argue in favor of such smaller masses. These first black holes may well leave the halos in which they formed for even rather modest kick velocities >~ 10 km/s. Nevertheless, up to about one hundred thousand of these first black holes may remain in the Milky Way. The realization that structure formation began within one hundred million years after big bang makes it difficult to study observationally these first crucial steps. Future observatories have hence to focus on larger collecting areas and wavelengths for which the universe is transparent up to redshifts of 30. XEUS offers the chance to open a new window to these so far dark ages. The limiting masses quoted here rely on stellar models of primordial stars that do not include rotation, magnetic fields or mass loss and hence are somewhat uncertain.

  1. Magnetic holes in the solar wind. [(interplanetary magnetic fields)

    NASA Technical Reports Server (NTRS)

    Turner, J. M.; Burlaga, L. F.; Ness, N. F.; Lemaire, J. F.

    1976-01-01

    An analysis is presented of high resolution interplanetary magnetic field measurements from the magnetometer on Explorer 43 which showed that low magnetic field intensities in the solar wind at 1 AU occur as distinct depressions or 'holes'. These magnetic holes are new kinetic-scale phenomena, having a characteristic dimension on the order of 20,000 km. They occurred at a rate of 1.5/day in the 18-day time span (March 18 to April 6, 1971) that was analyzed. Most of the magnetic holes are characterized by both a depression in the absolute value of the magnetic field, and a change in the magnetic field direction; some of these are possibly the result of magnetic merging. However, in other cases the magnetic field direction does not change; such holes are not due to magnetic merging, but might be a diamagnetic effect due to localized plasma inhomogeneities.

  2. Deep bore hole instrumentation along San Francisco Bay Bridges

    SciTech Connect

    Bakun, W.; Bowman, J.; Clymer, R.; Foxall, W.; Hipley, P.; Hollfelder, J.; Hutchings, L.; Jarpe, S.; Kasameyer, P.; McEvilly, T.; Mualchin, L.; Palmer, M.

    1998-10-01

    The Bay Bridges down hole network consists of sensors in bore holes that are drilled 100 ft. into bedrock around and in the San Francisco Bay. Between 2 and 8 instruments have been spaced along the Dumbarton, San Mateo, Bay, and San Rafael bridges. The instruments will provide multiple use data that is important to geotechnical, structural engineering, and seismological studies. The holes are between 100 and 1000 ft deep and were drilled by Caltrans. There are twenty- one sensor packages at fifteen sites. Extensive financial support is being contributed by Caltrans, UCB, LBL, LLNL-LDRD, U.C. Campus/Laboratory Collaboration (CLC) program, and USGS. The down hole instrument package contains a three component HS-1 seismometer and three orthogonal Wilcox 73 1 accelerometers, and is capable of recording a micro g from local M = 1.0 earthquakes to 0.5 g strong ground motion form large Bay Area earthquakes.

  3. Phase transitions of black holes in massive gravity

    NASA Astrophysics Data System (ADS)

    Fernando, Sharmanthie

    2016-05-01

    In this paper, we have studied thermodynamics of a black hole in massive gravity in the canonical ensemble. The massive gravity theory in consideration here has a massive graviton due to Lorentz symmetry breaking. The black hole studied here has a scalar charge due to the massive graviton and is asymptotically anti-de Sitter (AdS). We have computed various thermodynamical quantities such as temperature, specific heat and free energy. Both the local and global stability of the black hole are studied by observing the behavior of the specific heat and the free energy. We have observed that there is a first-order phase transition between small (SBH) and large black hole (LBH) for a certain range of the scalar charge. This phase transition is similar to the liquid/gas phase transition at constant temperature for a van der Waals fluid. The coexistence curves for the SBH and LBH branches are also discussed in detail.

  4. Film cooling effectiveness and heat transfer with injection through holes

    NASA Technical Reports Server (NTRS)

    Eriksen, V. L.

    1971-01-01

    An experimental investigation of the local film cooling effectiveness and heat transfer downstream of injection of air through discrete holes into a turbulent boundary layer of air on a flat plate is reported. Secondary air is injected through a single hole normal to the main flow and through both a single hole and a row of holes spaced at three diameter intervals with an injection angle of 35 deg to the main flow. Two values of the mainstream Reynolds number are used; the blowing rate is varied from 0.1 to 2.0. Photographs of a carbon dioxide-water fog injected into the main flow at an angle of 90 deg are also presented to show interaction between the jet and mainstream.

  5. Final state boundary condition of the Schwarzschild black hole

    SciTech Connect

    Ahn, Doyeol

    2006-10-15

    It is shown that the internal stationary state of the Schwarzschild black hole can be represented by a maximally entangled two-mode squeezed state of collapsing matter and infalling Hawking radiation. The final boundary condition at the singularity is then described by the random unitary transformation acting on the collapsing matter field. The outgoing Hawking radiation is obtained by the final-state projection on the total wave function, which looks like a quantum teleportation process without the classical information transmitted. The black hole evaporation process as seen by the observer outside the black hole is now a unitary process but nonlocal physics is required to transmit the information outside the black hole. It is also shown that the final-state projection by the evaporation process is strongly affected by the quantum state outside the event horizon, which clearly violates the locality principle.

  6. Ultrarelativistic black hole formation.

    PubMed

    East, William E; Pretorius, Frans

    2013-03-01

    We study the head-on collision of fluid particles well within the kinetic energy dominated regime (γ = 8 to 12) by numerically solving the Einstein-hydrodynamic equations. We find that the threshold for black hole formation is lower (by a factor of a few) than simple hoop conjecture estimates, and, moreover, near this threshold two distinct apparent horizons first form postcollision and then merge. We argue that this can be understood in terms of a gravitational focusing effect. The gravitational radiation reaches luminosities of 0.014 c(5)/G, carrying 16 ± 2% of the total energy.

  7. Surfing a Black Hole

    NASA Astrophysics Data System (ADS)

    2002-10-01

    Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours [1] Summary An international team of astronomers [2], lead by researchers at the Max-Planck Institute for Extraterrestrial Physics (MPE) , has directly observed an otherwise normal star orbiting the supermassive black hole at the center of the Milky Way Galaxy. Ten years of painstaking measurements have been crowned by a series of unique images obtained by the Adaptive Optics (AO) NAOS-CONICA (NACO) instrument [3] on the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. It turns out that earlier this year the star approached the central Black Hole to within 17 light-hours - only three times the distance between the Sun and planet Pluto - while travelling at no less than 5000 km/sec . Previous measurements of the velocities of stars near the center of the Milky Way and variable X-ray emission from this area have provided the strongest evidence so far of the existence of a central Black Hole in our home galaxy and, implicitly, that the dark mass concentrations seen in many nuclei of other galaxies probably are also supermassive black holes. However, it has not yet been possible to exclude several alternative configurations. In a break-through paper appearing in the research journal Nature on October 17th, 2002, the present team reports their exciting results, including high-resolution images that allow tracing two-thirds of the orbit of a star designated "S2" . It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the Milky Way. The orbital period is just over 15 years. The new measurements exclude with high confidence that the central dark mass consists of a cluster of unusual stars or elementary particles, and leave little doubt of the presence of a supermassive black hole at the centre of the galaxy in which we live . PR Photo 23a/02 : NACO image of the central region of the Milky Way

  8. Enzymatic versus inorganic oxygen reduction catalysts: comparison of the energy levels in a free-energy scheme.

    PubMed

    Kjaergaard, Christian H; Rossmeisl, Jan; Nørskov, Jens K

    2010-04-19

    In this paper, we present a method to directly compare the energy levels of intermediates in enzymatic and inorganic oxygen reduction catalysts. We initially describe how the energy levels of a Pt(111) catalyst, operating at pH = 0, are obtained. By a simple procedure, we then convert the energy levels of cytochrome c oxidase (CcO) models obtained at physiological pH = 7 to the energy levels at pH = 0, which allows for comparison. Furthermore, we illustrate how different bias voltages will affect the free-energy landscapes of the catalysts. This allows us to determine the so-called theoretical overpotential of each system, which is shown to be significantly lower for the enzymatic catalysts compared to the inorganic Pt(111) catalyst. Finally, we construct theoretical polarization curves for the CcO models, in order to illustrate the effect of the low overpotentials on turnover rates per site. PMID:20380458

  9. Charge separation at nanoscale interfaces: Energy-level alignment including two-quasiparticle interactions

    SciTech Connect

    Li, Huashan; Lin, Zhibin; Lusk, Mark T. Wu, Zhigang

    2014-10-21

    The universal and fundamental criteria for charge separation at interfaces involving nanoscale materials are investigated. In addition to the single-quasiparticle excitation, all the two-quasiparticle effects including exciton binding, Coulomb stabilization, and exciton transfer are considered, which play critical roles on nanoscale interfaces for optoelectronic applications. We propose a scheme allowing adding these two-quasiparticle interactions on top of the single-quasiparticle energy level alignment for determining and illuminating charge separation at nanoscale interfaces. Employing the many-body perturbation theory based on Green's functions, we quantitatively demonstrate that neglecting or simplifying these crucial two-quasiparticle interactions using less accurate methods is likely to predict qualitatively incorrect charge separation behaviors at nanoscale interfaces where quantum confinement dominates.

  10. Accuracy of analytic energy level formulas applied to hadronic spectroscopy of heavy mesons

    NASA Technical Reports Server (NTRS)

    Badavi, Forooz F.; Norbury, John W.; Wilson, John W.; Townsend, Lawrence W.

    1988-01-01

    Linear and harmonic potential models are used in the nonrelativistic Schroedinger equation to obtain article mass spectra for mesons as bound states of quarks. The main emphasis is on the linear potential where exact solutions of the S-state eigenvalues and eigenfunctions and the asymptotic solution for the higher order partial wave are obtained. A study of the accuracy of two analytical energy level formulas as applied to heavy mesons is also included. Cornwall's formula is found to be particularly accurate and useful as a predictor of heavy quarkonium states. Exact solution for all partial waves of eigenvalues and eigenfunctions for a harmonic potential is also obtained and compared with the calculated discrete spectra of the linear potential. Detailed derivations of the eigenvalues and eigenfunctions of the linear and harmonic potentials are presented in appendixes.

  11. Wave energy level and geographic setting correlate with Florida beach water quality.

    PubMed

    Feng, Zhixuan; Reniers, Ad; Haus, Brian K; Solo-Gabriele, Helena M; Kelly, Elizabeth A

    2016-03-15

    Many recreational beaches suffer from elevated levels of microorganisms, resulting in beach advisories and closures due to lack of compliance with Environmental Protection Agency guidelines. We conducted the first statewide beach water quality assessment by analyzing decadal records of fecal indicator bacteria (enterococci and fecal coliform) levels at 262 Florida beaches. The objectives were to depict synoptic patterns of beach water quality exceedance along the entire Florida shoreline and to evaluate their relationships with wave condition and geographic location. Percent exceedances based on enterococci and fecal coliform were negatively correlated with both long-term mean wave energy and beach slope. Also, Gulf of Mexico beaches exceeded the thresholds significantly more than Atlantic Ocean ones, perhaps partially due to the lower wave energy. A possible linkage between wave energy level and water quality is beach sand, a pervasive nonpoint source that tends to harbor more bacteria in the low-wave-energy environment.

  12. Calculation of energy levels and transition amplitudes for barium and radium.

    SciTech Connect

    Dzuba, V. A.; Flambaum, V. V.; Physics; Univ. of New South Wales

    2007-01-01

    The radium atom is a promising system for studying parity and time invariance violating weak interactions. However, available experimental spectroscopic data for radium are insufficient for designing an optimal experimental setup. We calculate the energy levels and transition amplitudes for radium states of significant interest. Forty states corresponding to all possible configurations consisting of the 7s, 7p and 6d single-electron states as well as the states of the 7s8s, 7s8p and 7s7d configurations have been calculated. The energies of ten of these states corresponding to the 6d{sup 2}, 7s8s, 7p{sup 2} and 6d7p configurations are not known from experiment. Calculations for barium are used to control the accuracy.

  13. Determination of energy level alignment at metal/molecule interfaces by in-device electrical spectroscopy.

    PubMed

    Gobbi, M; Pietrobon, L; Atxabal, A; Bedoya-Pinto, A; Sun, X; Golmar, F; Llopis, R; Casanova, F; Hueso, L E

    2014-01-01

    The energetics of metal/molecular semiconductor interfaces plays a fundamental role in organic electronics, determining the performance of very diverse devices. So far, information about the energy level alignment has been most commonly gained by spectroscopy techniques that typically require experimental conditions far from the real device operation. Here we demonstrate that a simple three-terminal device allows the acquisition of spectroscopic information about the metal/molecule energy alignment in real operative condition. As a proof of principle, we employ the proposed device to measure the energy barrier height between different clean metals and C60 molecules and we recover typical results from photoemission spectroscopy. The device is designed to inject a hot electron current directly into the molecular level devoted to charge transport, disentangling the contributions of both the interface and the bulk to the device total resistance, with important implications for spintronics and low-temperature physics.

  14. Energy levels and radiative rates for Cr-like Cu VI and Zn VII

    NASA Astrophysics Data System (ADS)

    Aggarwal, K. M.; Bogdanovich, P.; Keenan, F. P.; Kisielius, R.

    2016-09-01

    Energy levels and radiative rates (A-values) for transitions in Cr-like Cu VI and Zn VII are reported. These data are determined in the quasi-relativistic approach (QR), by employing a very large configuration interaction (CI) expansion which is highly important for these ions. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST and other available theoretical data, for a majority of the levels. The A-values (and resultant lifetimes) are listed for all significantly contributing E1, E2 and M1 radiative transitions among the energetically lowest 322 levels of each ion.

  15. Energy levels, lifetimes, and transition probabilities for Mn XII and Ge XIX

    SciTech Connect

    El-Sayed, Fatma

    2014-09-15

    Energy levels, transition probabilities, oscillator strengths, line strengths, and lifetimes have been calculated for silicon-like manganese and germanium, Mn XII and Ge XIX. The configurations 3s{sup 2}3p{sup 2}, 3s3p{sup 3}, 3s{sup 2}3p3d, 3s3p{sup 2}3d, and 3p{sup 4} were used in the calculations and 88 fine-structure levels were obtained. The fully relativistic GRASP code has been adopted, and results are reported for all electric dipole, electric quadrupole, magnetic dipole, and magnetic quadrupole transitions among levels of Mn XII and Ge XIX. Comparisons have been made with available theoretical and experimental results.

  16. Interacting Electrons in Parabolic Quantum Dots:. Energy Levels, Addition Energies, and Charge Distributions

    NASA Astrophysics Data System (ADS)

    Schreiber, Michael; Siewert, Jens; Vojta, Thomas

    We investigate the properties of interacting electrons in a parabolic confinement. To this end we numerically diagonalize the Hamiltonian using the Hartree-Fock based diagonalization method which is related to the configuration interaction approach. We study different types of interactions, Coulomb as well as short range. In addition to the ground state energy we calculate the spatial charge distribution and compare the results to those of the classical calculation. We find that a sufficiently strong screened Coulomb interaction produces energy level bunching for classical as well as for quantum-mechanical dots. Bunching in the quantum-mechanical system occurs due to an interplay of kinetic and interaction energy, moreover, it is observed well before reaching the limit of a Wigner crystal. It also turns out that the shell structure of classical and quantum mechanical spatial charge distributions is quite similar.

  17. Interacting Electrons in Parabolic Quantum Dots:. Energy Levels, Addition Energies, and Charge Distributions

    NASA Astrophysics Data System (ADS)

    Schreiber, Michael; Siewert, Jens; Vojta, Thomas

    2001-08-01

    We investigate the properties of interacting electrons in a parabolic confinement. To this end we numerically diagonalize the Hamiltonian using the Hartree-Fock based diagonalization method which is related to the configuration interaction approach. We study different types of interactions, Coulomb as well as short range. In addition to the ground state energy we calculate the spatial charge distribution and compare the results to those of the classical calculation. We find that a sufficiently strong screened Coulomb interaction produces energy level bunching for classical as well as for quantum-mechanical dots. Bunching in the quantum-mechanical system occurs due to an interplay of kinetic and interaction energy, moreover, it is observed well before reaching the limit of a Wigner crystal. It also turns out that the shell structure of classical and quantum mechanical spatial charge distributions is quite similar.

  18. Energy levels and spectral lines in the X-ray spectra of highly charged W XLIV

    NASA Astrophysics Data System (ADS)

    Hao, Liang-Huan; Kang, Xiao-Ping

    2014-07-01

    The multi-configuration Dirac-Hartree-Fock method is employed to calculate the fine-structure energy levels, wavelengths, transition probabilities, and oscillator strengths for electric dipole allowed (E1) and forbidden (M1, E2, M2) lines for the 4 s 24 p and 4 s4 p 2 configurations of W XLIV. The valence-valence and core-valence correlation effects are accounted for in a systematic way. Breit interactions and quantum electrodynamics (QED) effects are estimated in subsequent relativistic configuration interaction (CI) calculations. The present results are in good agreement with other available theoretical and experimental values, and we predict new data for several levels where no other theoretical and/or experimental results are available, precise measurements are clearly needed here.

  19. Controlling energy level offsets in organic/organic heterostructures using intramolecular polar bonds

    NASA Astrophysics Data System (ADS)

    Duhm, Steffen; Salzmann, Ingo; Heimel, Georg; Oehzelt, Martin; Haase, Anja; Johnson, Robert L.; Rabe, Jürgen P.; Koch, Norbert

    2009-01-01

    The impact of intramolecular polar bonds (IPBs) on the energy level alignment in layered systems of rodlike conjugated molecules standing on the substrate was investigated for pentacene (PEN) and perfluoropentacene (PFP) on SiO2 using ultraviolet photoelectron spectroscopy. A remarkably large energy offset of 1.75 eV was found between the highest occupied molecular orbital (HOMO) levels of PEN and PFP caused by IPBs at the surface of standing PFP layers. This large HOMO-level offset results in a narrow intermolecular energy gap of approximately 0.4 eV at the interface between PEN and PFP layers. However, the absence of significant spatial overlap of PEN and PFP electron wave functions across the layers suppresses interlayer optical transitions.

  20. Isomeric and ground state energy level measurements of natural tellurium isotopes via (γ,n) reaction

    NASA Astrophysics Data System (ADS)

    Tamkas, M.; Akcali, O.; Durusoy, A.

    2015-04-01

    We have planned to measure isomeric and ground state energy levels in 120Te(γ,n)119m,gTe, 122Te(γ,n)121m,gTe, 128Te(γ,n)127m,gTe, 130Te(γ,n)129m,gTe photonuclear reactions of natural tellurium induced by bremsstrahlung photons with end-point energy at 18 MeV. The sample was irradiated in the clinical linear electron accelerator (Philips SLi-25) at Akdeniz University Hospital. The gamma spectrum of the tellurium sample was measured using HP(Ge) semiconductor detector (ORTEC) and multi channel analyzer. We used both MAESTRO (ORTEC) and home made root based gui program (Theia) for data analyzing. The obtained experimental data values are compared with NUDAT energy values.

  1. Energy levels and radiative rates for Cr-like Cu VI and Zn VII

    NASA Astrophysics Data System (ADS)

    Aggarwal, K. M.; Bogdanovich, P.; Keenan, F. P.; Kisielius, R.

    2016-09-01

    Energy levels and radiative rates (A-values) for transitions in Cr-like Cu VI and Zn VII are reported. These data are determined in the quasi-relativistic approach (QR), by employing a very large configuration interaction (CI) expansion which is highly important for these ions. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST and other available theoretical data, for a majority of the levels. The A-values (and resultant lifetimes) are listed for all significantly contributing E1, E2 and M1 radiative transitions among the energetically lowest 322 levels of each ion.

  2. Organic semiconductor density of states controls the energy level alignment at electrode interfaces

    PubMed Central

    Oehzelt, Martin; Koch, Norbert; Heimel, Georg

    2014-01-01

    Minimizing charge carrier injection barriers and extraction losses at interfaces between organic semiconductors and metallic electrodes is critical for optimizing the performance of organic (opto-) electronic devices. Here, we implement a detailed electrostatic model, capable of reproducing the alignment between the electrode Fermi energy and the transport states in the organic semiconductor both qualitatively and quantitatively. Covering the full phenomenological range of interfacial energy level alignment regimes within a single, consistent framework and continuously connecting the limiting cases described by previously proposed models allows us to resolve conflicting views in the literature. Our results highlight the density of states in the organic semiconductor as a key factor. Its shape and, in particular, the energy distribution of electronic states tailing into the fundamental gap is found to determine both the minimum value of practically achievable injection barriers as well as their spatial profile, ranging from abrupt interface dipoles to extended band-bending regions. PMID:24938867

  3. Time resolved fluorescence from parity mixed rotational energy levels - Collisions vs electric field effects

    NASA Astrophysics Data System (ADS)

    Mandich, M. L.; Gaebe, C. E.; Gottscho, R. A.

    1985-10-01

    Moore et al. (1984) have described a method for the in situ and nonintrusive measurement of plasma electric fields by a method involving the excitation of a parity or Lambda doublet of the polar diatomic molecule BCl. Three approximations are made in deriving a theoretical relationship between field strength and the forbidden to allowed line intensity ratio. One approximation is related to the neglect of collisional transfer, while another is based on the neglect of coherent phenomena, such as quantum beats between the mixed parity levels. New experimental evidence is provided, and it is shown that the latter approximation is not always justified. The last assumption is the neglect of hyperfine structure effects on field-dependent line intensities and polarizations. Hyperfine effects are accounted for in a phenomenological fashion which is justified empirically. Attention is given to both time-resolved and time-integrated fluorescence measurements from parity-mixed energy levels in the polar diatomic molecule BCl.

  4. Wave energy level and geographic setting correlate with Florida beach water quality.

    PubMed

    Feng, Zhixuan; Reniers, Ad; Haus, Brian K; Solo-Gabriele, Helena M; Kelly, Elizabeth A

    2016-03-15

    Many recreational beaches suffer from elevated levels of microorganisms, resulting in beach advisories and closures due to lack of compliance with Environmental Protection Agency guidelines. We conducted the first statewide beach water quality assessment by analyzing decadal records of fecal indicator bacteria (enterococci and fecal coliform) levels at 262 Florida beaches. The objectives were to depict synoptic patterns of beach water quality exceedance along the entire Florida shoreline and to evaluate their relationships with wave condition and geographic location. Percent exceedances based on enterococci and fecal coliform were negatively correlated with both long-term mean wave energy and beach slope. Also, Gulf of Mexico beaches exceeded the thresholds significantly more than Atlantic Ocean ones, perhaps partially due to the lower wave energy. A possible linkage between wave energy level and water quality is beach sand, a pervasive nonpoint source that tends to harbor more bacteria in the low-wave-energy environment. PMID:26892203

  5. S-matrix Calculations of Energy Levels of the Lithium Isoelectronic Sequence

    SciTech Connect

    sapirstein, J; Cheng, K T

    2010-11-02

    A QED approach to the calculation of the spectra of the lithium isoelectronic sequence is implemented. A modified Furry representation based on the Kohn-Sham potential is used to evaluate all one- and two-photon diagrams with the exception of the two-loop Lamb shift. Three-photon diagrams are estimated with Hamiltonian methods. After incorporating recent calculations of the two-loop Lamb shift and recoil corrections a comprehensive tabulation of the 2s, 2p{sub 1/2} and 2p{sub 3/2} energy levels as well as the 2s - 2p{sub 1/2} and 2s - 2p{sub 3/2} transition energies for Z = 10 - 100 is presented.

  6. Determination of energy level alignment at metal/molecule interfaces by in-device electrical spectroscopy.

    PubMed

    Gobbi, M; Pietrobon, L; Atxabal, A; Bedoya-Pinto, A; Sun, X; Golmar, F; Llopis, R; Casanova, F; Hueso, L E

    2014-01-01

    The energetics of metal/molecular semiconductor interfaces plays a fundamental role in organic electronics, determining the performance of very diverse devices. So far, information about the energy level alignment has been most commonly gained by spectroscopy techniques that typically require experimental conditions far from the real device operation. Here we demonstrate that a simple three-terminal device allows the acquisition of spectroscopic information about the metal/molecule energy alignment in real operative condition. As a proof of principle, we employ the proposed device to measure the energy barrier height between different clean metals and C60 molecules and we recover typical results from photoemission spectroscopy. The device is designed to inject a hot electron current directly into the molecular level devoted to charge transport, disentangling the contributions of both the interface and the bulk to the device total resistance, with important implications for spintronics and low-temperature physics. PMID:24946715

  7. S-matrix calculations of energy levels of the lithium isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Sapirstein, J.; Cheng, K. T.

    2012-06-01

    A QED approach to the calculation of the spectra of the lithium isoelectronic sequence is implemented. A modified Furry representation based on the Kohn-Sham potential is used to evaluate all one- and two-photon diagrams with the exception of the two-loop Lamb shift. Three-photon diagrams are estimated with Hamiltonian methods. After incorporating recent calculations of the two-loop Lamb shift and recoil corrections a comprehensive tabulation of the 2s, 2p1/2 and 2p3/2 energy levels as well as the 2s-2p1/2 and 2s-2p3/2 transition energies for Z=10-100 is presented.

  8. S-matrix calculations of energy levels of the lithium isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Sapirstein, J.; Cheng, K. T.

    2011-01-01

    A QED approach to the calculation of the spectra of the lithium isoelectronic sequence is implemented. A modified Furry representation based on the Kohn-Sham potential is used to evaluate all one- and two-photon diagrams with the exception of the two-loop Lamb shift. Three-photon diagrams are estimated with Hamiltonian methods. After incorporating recent calculations of the two-loop Lamb shift and recoil corrections, a comprehensive tabulation of the 2s, 2p1/2, and 2p3/2 energy levels as well as the 2s-2p1/2 and 2s-2p3/2 transition energies for Z=10-100 is presented.

  9. Energy levels and radiative rates for transitions in Cr-like Co IV and Ni V

    NASA Astrophysics Data System (ADS)

    Aggarwal, K. M.; Bogdanovich, P.; Karpuškienė, R.; Keenan, F. P.; Kisielius, R.; Stancalie, V.

    2016-01-01

    We report calculations of energy levels and radiative rates (A-values) for transitions in Cr-like Co IV and Ni V. The quasi-relativistic Hartree-Fock (QRHF) code is adopted for calculating the data although GRASP (general-purpose relativistic atomic structure package) and flexible atomic code (FAC) have also been employed for comparison purposes. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST for a majority of the levels. However, there are discrepancies for a few levels of up to 3%. The A-values are listed for all significantly contributing E1, E2 and M1 transitions, and the corresponding lifetimes reported, although unfortunately no previous theoretical or experimental results exist to compare with our data.

  10. Spectrum and energy levels of quadruply-ionized molybdenum (Mo V)

    NASA Astrophysics Data System (ADS)

    Reader, Joseph; Tauheed, Ahmad

    2015-07-01

    The spectrum of quadruply-ionized molybdenum Mo V was observed from 200 to 4700 Å with sliding spark discharges on 10.7 m normal- and grazing-incidence spectrographs. The existing analyses of this spectrum (Tauheed et al 1985 Phys. Scr. 31 369; Cabeza et al 1986 Phys. Scr. 34 223) were extended to include the 5s2, 5p2, 5s5d, 5s6s, 4d5f, and 4d5g configurations as well as the missing 3H6 level of 4d4f and about 75 levels of the core-excited configuration 4p54d3. The values of the 4d5d 1S0, 5s5p 1P1, and 4d6p 3P0 levels were revised. There are now about 900 lines classified as transitions between 66 even parity and 191 odd parity energy levels. Of these, about 600 lines and 130 levels are new. From the optimized energy level values, Ritz-type wavelengths were determined for about 380 lines, with uncertainties varying from 0.0003 to 0.002 Å. The observed configurations were theoretically interpreted by means of Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels. The fitted parameters were used to calculate oscillator strengths for all classified lines. A few unclassified lines and undesignated levels are also given. An improved value for the ionization energy was obtained by combining the observed energy of the 4d5g configuration with an ab initio calculation of its term value. The adopted value is 438 900 ± 150 cm-1 (54.417 ± 0.019 eV).

  11. Energy levels, radiative rates, and lifetimes for transitions in W XL

    SciTech Connect

    Aggarwal, Kanti M. Keenan, Francis P.

    2014-11-15

    Energy levels and radiative rates are reported for transitions in Br-like tungsten, W XL, calculated with the general-purpose relativistic atomic structure package (GRASP). Configuration interaction (CI) has been included among 46 configurations (generating 4215 levels) over a wide energy range up to 213 Ryd. However, for conciseness results are only listed for the lowest 360 levels (with energies up to ∼43 Ryd), which mainly belong to the 4s{sup 2}4p{sup 5},4s{sup 2}4p{sup 4}4d,4s{sup 2}4p{sup 4}4f,4s4p{sup 6},4p{sup 6}4d,4s4p{sup 5}4d,4s{sup 2}4p{sup 3}4d{sup 2}, and 4s{sup 2}4p{sup 3}4d4f configurations, and provided for four types of transitions, E1, E2, M1, and M2. Comparisons are made with existing (but limited) results. However, to fully assess the accuracy of our data, analogous calculations have been performed with the flexible atomic code, including an even larger CI than in GRASP. Our energy levels are estimated to be accurate to better than 0.02 Ryd, whereas results for radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions.

  12. Reliable Energy Level Alignment at Physisorbed Molecule–Metal Interfaces from Density Functional Theory

    PubMed Central

    2015-01-01

    A key quantity for molecule–metal interfaces is the energy level alignment of molecular electronic states with the metallic Fermi level. We develop and apply an efficient theoretical method, based on density functional theory (DFT) that can yield quantitatively accurate energy level alignment information for physisorbed metal–molecule interfaces. The method builds on the “DFT+Σ” approach, grounded in many-body perturbation theory, which introduces an approximate electron self-energy that corrects the level alignment obtained from conventional DFT for missing exchange and correlation effects associated with the gas-phase molecule and substrate polarization. Here, we extend the DFT+Σ approach in two important ways: first, we employ optimally tuned range-separated hybrid functionals to compute the gas-phase term, rather than rely on GW or total energy differences as in prior work; second, we use a nonclassical DFT-determined image-charge plane of the metallic surface to compute the substrate polarization term, rather than the classical DFT-derived image plane used previously. We validate this new approach by a detailed comparison with experimental and theoretical reference data for several prototypical molecule–metal interfaces, where excellent agreement with experiment is achieved: benzene on graphite (0001), and 1,4-benzenediamine, Cu-phthalocyanine, and 3,4,9,10-perylene-tetracarboxylic-dianhydride on Au(111). In particular, we show that the method correctly captures level alignment trends across chemical systems and that it retains its accuracy even for molecules for which conventional DFT suffers from severe self-interaction errors. PMID:25741626

  13. Reliable energy level alignment at physisorbed molecule-metal interfaces from density functional theory.

    PubMed

    Egger, David A; Liu, Zhen-Fei; Neaton, Jeffrey B; Kronik, Leeor

    2015-04-01

    A key quantity for molecule-metal interfaces is the energy level alignment of molecular electronic states with the metallic Fermi level. We develop and apply an efficient theoretical method, based on density functional theory (DFT) that can yield quantitatively accurate energy level alignment information for physisorbed metal-molecule interfaces. The method builds on the "DFT+Σ" approach, grounded in many-body perturbation theory, which introduces an approximate electron self-energy that corrects the level alignment obtained from conventional DFT for missing exchange and correlation effects associated with the gas-phase molecule and substrate polarization. Here, we extend the DFT+Σ approach in two important ways: first, we employ optimally tuned range-separated hybrid functionals to compute the gas-phase term, rather than rely on GW or total energy differences as in prior work; second, we use a nonclassical DFT-determined image-charge plane of the metallic surface to compute the substrate polarization term, rather than the classical DFT-derived image plane used previously. We validate this new approach by a detailed comparison with experimental and theoretical reference data for several prototypical molecule-metal interfaces, where excellent agreement with experiment is achieved: benzene on graphite (0001), and 1,4-benzenediamine, Cu-phthalocyanine, and 3,4,9,10-perylene-tetracarboxylic-dianhydride on Au(111). In particular, we show that the method correctly captures level alignment trends across chemical systems and that it retains its accuracy even for molecules for which conventional DFT suffers from severe self-interaction errors. PMID:25741626

  14. Energy levels and transition rates for helium-like ions with Z = 10-36

    NASA Astrophysics Data System (ADS)

    Si, R.; Guo, X. L.; Wang, K.; Li, S.; Yan, J.; Chen, C. Y.; Brage, T.; Zou, Y. M.

    2016-08-01

    Aims: Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods: The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results: We provide accurate energies for the lowest singly excited 70 levels among 1snl(n ≤ 6,l ≤ (n-1)) configurations and the lowest doubly excited 250 levels arising from the K-vacancy 2ln'l'(n' ≤ 6,l' ≤ (n'-1)) configurations of helium-like ions with Z = 10-36. Wavelengths, transition rates, oscillator strengths, and line strengths are calculated for the E1, M1, E2, and M2 transitions among these levels. The radiative lifetimes are reported for all the calculated levels. Conclusions: Our MBPT results for singly excited n ≤ 2 levels show excellent agreement with other elaborate calculations, while those for singly excited n ≥ 3 and doubly excited levels show significant improvements over previous theoretical results. Our results will be very helpful for astrophysical line identification and plasma diagnostics. Full Tables 1 and 2 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A141

  15. First-Principles Approach to Energy Level Alignment at Aqueous Semiconductor Interfaces

    NASA Astrophysics Data System (ADS)

    Hybertsen, Mark

    2015-03-01

    We have developed a first principles method to calculate the energy level alignment between semiconductor band edges and reference energy levels at aqueous interfaces. This alignment is fundamental to understand the electrochemical characteristics of any semiconductor electrode in general and the potential for photocatalytic activity in particular. For example, in the search for new photo-catalytic materials, viable candidates must demonstrate both efficient absorption of the solar spectrum and an appropriate alignment of the band edge levels in the semiconductor to the redox levels for the target reactions. In our approach, the interface-specific contribution to the electrostatic step across the interface is evaluated using density functional theory (DFT) based molecular dynamics to sample the physical interface structure and the corresponding change in the electrostatic potential at the interface. The reference electronic levels in the semiconductor and in the water are calculated using the GW approach, which naturally corrects for errors inherent in the use of Kohn-Sham energy eigenvalues to approximate the electronic excitation energies in each material. Taken together, our calculations provide the alignment of the semiconductor valence band edge to the centroid of the highest occupied 1b1 level in water. The known relationship of the 1b1 level to the normal hydrogen electrode completes the connection to electrochemical levels. We discuss specific results for GaN, ZnO, and TiO2. The effect of interface structural motifs, such as different degrees of water dissociation, and of dynamical characteristics, will be presented together with available experimental data. Work supported by the US Department of Energy, Office of Basic Energy Sciences under Contract No. DE-AC02-98CH10886.

  16. Acceleration of black hole universe

    NASA Astrophysics Data System (ADS)

    Zhang, T. X.; Frederick, C.

    2014-01-01

    Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

  17. Black holes as antimatter factories

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Dolgov, Alexander D.; Petrov, Alexey A.

    2009-09-01

    We consider accretion of matter onto a low mass black hole surrounded by ionized medium. We show that, because of the higher mobility of protons than electrons, the black hole would acquire positive electric charge. If the black hole's mass is about or below 1020 g, the electric field at the horizon can reach the critical value which leads to vacuum instability and electron-positron pair production by the Schwinger mechanism. Since the positrons are ejected by the emergent electric field, while electrons are back-captured, the black hole operates as an antimatter factory which effectively converts protons into positrons.

  18. Black holes and the multiverse

    NASA Astrophysics Data System (ADS)

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

    2016-02-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

  19. How black holes saved relativity

    NASA Astrophysics Data System (ADS)

    Prescod-Weinstein, Chanda

    2016-02-01

    While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.

  20. Can Black Hole Relax Unitarily?

    NASA Astrophysics Data System (ADS)

    Solodukhin, S. N.

    2005-03-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  1. Thermodynamics of Accelerating Black Holes

    NASA Astrophysics Data System (ADS)

    Appels, Michael; Gregory, Ruth; KubizÅák, David

    2016-09-01

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon—even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  2. A few remarks on the simulation and use of crystal field energy level schemes of the rare earth ions

    NASA Astrophysics Data System (ADS)

    Hölsä, Jorma; Lastusaari, Mika; Maryško, Miroslav; Tukia, Mika

    2005-02-01

    The usefulness of the simulation of the energy level schemes of the trivalent rare earth ( R3+) ions in the prediction of the properties of the rare earth compounds is demonstrated for a few selected cases emphasizing the connection between different spectroscopic and magnetic properties of the R 3+ ions. The importance of the calculated energy level schemes in the UV-VUV range in interpreting complicated spectra and designing new phosphors by energy transfer and quantum cutting is described. In the absence of direct measurements, the calculated energy level values can be very useful. The possibilities to interpret the magnetic properties of the R3+ (and R2+) ions are described by using the wave functions of the energy levels obtained from the energy level simulations. As a fine example, it is shown how the amount of an Eu 2+ impurity can be obtained from the calculation of the paramagnetic susceptibility as a function of temperature. The problems involved in the simulation of the 7FJ crystal field energy level scheme of the Eu 3+ ion are highlighted by using a comparison between the extensive literature data and calculated level schemes.

  3. Magnetic Hole observations in the near earth space

    NASA Astrophysics Data System (ADS)

    Xiao, T.; Shi, Q.; Li, L.; Pu, Z.; Zong, Q.; Fu, S.; Zhang, T.; Xie, L.; Sun, W.; Liu, Z.; Fazakerley, A. N.; Reme, H.; Lucek, E. A.

    2009-12-01

    Using Cluster magnetic field and plasma data, we study the magnetic holes in the solar wind at 1 AU. From statistical research, we find that the geometrical shape and the occurrence rate of magnetic holes in the solar wind do not show significant change from 0.72AU to 1AU in comparison with previous studies, which is therefore inferred that most of magnetic holes are formed and fully developed before 0.72 AU. We have also surveyed the relationship between the occurrence rate of the solar wind magnetic holes and the solar wind plasma parameters. It is found that the results are quite different between two types of holes, inferring that they are from different sources. All of these results helped us to discuss the formation mechanism of the magnetic holes in the solar wind. Magnetic depression structures (magnetic holes) of short time durations from seconds to minutes have also been studied using Cluster data in the high latitude cusp (which can be partially seen in Shi et al., JGR, in press, 2009JA014283.). Based on multi-spacecraft measurements, we found that they are spatial structures traveling across the spacecraft. These spatial features are confirmed by the calculation of the boundary normal directions and velocities using various methods. We discuss the possible formation mechanism of this type of small structures and propose that the existence of these magnetic holes in the cusp region might indicate that the mirror structures formed in the sheath could enter the cusp and survive, attributed to the open geometry of the cusp magnetic field, although the possibility of local generation of these structures can not be totally ruled out. Finally we compared the magnetic holes in the different regions of the near earth space.

  4. Experimental Evidence of the Origin of Nanophase Separation in Low Hole-Doped Colossal Magnetoresistant Manganites.

    PubMed

    Cortés-Gil, Raquel; Ruiz-González, M Luisa; González-Merchante, Daniel; Alonso, José M; Hernando, Antonio; Trasobares, Susana; Vallet-Regí, María; Rojo, Juan M; González-Calbet, José M

    2016-01-13

    While being key to understanding their intriguing physical properties, the origin of nanophase separation in manganites and other strongly correlated materials is still unclear. Here, experimental evidence is offered for the origin of the controverted phase separation mechanism in the representative La1-xCaxMnO3 system. For low hole densities, direct evidence of Mn(4+) holes localization around Ca(2+) ions is experimentally provided by means of aberration-corrected scanning transmission electron microscopy combined with electron energy loss spectroscopy. These localized holes give rise to the segregated nanoclusters, within which double exchange hopping between Mn(3+) and Mn(4+) remains restricted, accounting for the insulating character of perovskites with low hole density. This localization is explained in terms of a simple model in which Mn(4+) holes are bound to substitutional divalent Ca(2+) ions.

  5. Unmanned Ground Vehicle Navigation and Coverage Hole Patching in Wireless Sensor Networks

    ERIC Educational Resources Information Center

    Zhang, Guyu

    2013-01-01

    This dissertation presents a study of an Unmanned Ground Vehicle (UGV) navigation and coverage hole patching in coordinate-free and localization-free Wireless Sensor Networks (WSNs). Navigation and coverage maintenance are related problems since coverage hole patching requires effective navigation in the sensor network environment. A…

  6. Particle-hole duality, integrability, and Russian doll BCS model

    NASA Astrophysics Data System (ADS)

    Bork, L. V.; Pogosov, W. V.

    2015-08-01

    We address a generalized Richardson model (Russian doll BCS model), which is characterized by the breaking of time-reversal symmetry. This model is known to be exactly solvable and integrable. We point out that the Russian doll BCS model, on the level of Hamiltonian, is also particle-hole symmetric. This implies that the same state can be expressed both in the particle and hole representations with two different sets of Bethe roots. We then derive exact relations between Bethe roots in the two representations, which can hardly be obtained staying on the level of Bethe equations. In a quasi-classical limit, similar identities for usual Richardson model, known from literature, are recovered from our results. We also show that these relations for Richardson roots take a remarkably simple form at half-filling and for a symmetric with respect to the middle of the interaction band distribution of one-body energy levels, since, in this special case, the rapidities in the particle and hole representations up to the translation satisfy the same system of equations.

  7. New geometries for black hole horizons

    NASA Astrophysics Data System (ADS)

    Armas, Jay; Blau, Matthias

    2015-07-01

    We construct several classes of worldvolume effective actions for black holes by integrating out spatial sections of the worldvolume geometry of asymptotically flat black branes. This provides a generalisation of the blackfold approach for higher-dimensional black holes and yields a map between different effective theories, which we exploit by obtaining new hydrodynamic and elastic transport coefficients via simple integrations. Using Euclidean minimal surfaces in order to decouple the fluid dynamics on different sections of the worldvolume, we obtain local effective theories for ultraspinning Myers-Perry branes and helicoidal black branes, described in terms of a stress-energy tensor, particle currents and non-trivial boost vectors. We then study in detail and present novel compact and non-compact geometries for black hole horizons in higher-dimensional asymptotically flat space-time. These include doubly-spinning black rings, black helicoids and helicoidal p-branes as well as helicoidal black rings and helicoidal black tori in D ≥ 6.

  8. Deep Hole in 'Clovis' (False Color)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    At a rock called 'Clovis,' the rock abrasion tool on NASA's Mars Exploration Rover Spirit cut a 9-millimeter (0.35-inch) hole during the rover's 216th martian day, or sol (Aug. 11, 2004). The hole is the deepest drilled in a rock on Mars so far. This false color view was made from images taken by Spirit's panoramic camera on sol 226 (Aug. 21, 2004) at around 12:50 p.m. local true solar time -- early afternoon in Gusev Crater on Mars. To the right is a 'brush flower' of circles produced by scrubbing the surface of the rock with the abrasion tool's wire brush. Scientists used rover's Moessbauer spectrometer and alpha particle X-ray spectrometer to look for iron-bearing minerals and determine the elemental chemical composition of the rock. This composite combines images taken with the camera's 750-, 530-, and 430-nanometer filters. The grayish-blue hue in this image suggests that the interior of the rock contains iron minerals that are less oxidized than minerals on the surface. The diameter of the hole cut into the rock is 4.5 centimeters (1.8 inches).

  9. Black Hole Thermodynamics and Lorentz Symmetry

    NASA Astrophysics Data System (ADS)

    Jacobson, Ted; Wall, Aron C.

    2010-08-01

    Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe and extend the arguments leading to that conclusion. We suggest the inference that local Lorentz symmetry may be an emergent property of the macroscopic world with origins in a microscopic second law of causal horizon thermodynamics.

  10. Tool For Making Curved Holes

    NASA Technical Reports Server (NTRS)

    Allard, Robert; Calve, Andrew; Pastreck, Edwin; Padden, Edward

    1992-01-01

    Tool for use in electrical-discharge machining (EDM) guides EDM electrode in making curved holes. Guide rod fits in slot in arm, which moves through arc. Motion drives electrode into workpiece along desired curved path. Electrode burns into workpiece while arm rotates on spindle. Discharge cuts hole of same radius of curvature.

  11. Thermodynamic Curvature and Black Holes

    NASA Astrophysics Data System (ADS)

    Ruppeiner, George

    In my talk, I will discuss black hole thermodynamics, particularly what happens when you add thermodynamic curvature to the mix. Although black hole thermodynamics is a little off the main theme of this workshop, I hope nevertheless that my message will be of some interest to researchers in supersymmetry and supergravity.

  12. The performance of brown egg-type layers fed different protein and energy levels in the tropics.

    PubMed

    Olomu, J M; Offiong, S A

    1983-02-01

    The effects of feeding three protein levels (16, 18, and 20%), each at three metabolizable energy levels (2400, 2600, and 2800 kcal/kg diet), were studied with 990 caged Warren Studler Sex-Sal Link pullets over a 336-day laying period. Dietary protein had no significant effects on hen-day egg production, egg weight, Haugh units, feed intake, feed conversion, feed cost per dozen eggs, caloric intake, egg weights, and final body weight. Protein consumption on all levels of dietary protein was over 20 g per bird per day and increased significantly with increases in dietary protein. Mortality was lowest on the highest protein level. The highest energy level (2800 kcal/kg diet) significantly depressed egg production and feed and protein intake. The feed costs per dozen eggs increased significantly with increases in dietary energy level. Caloric intake and final body weights were similar for the medium (2600 kcal/kg diet) and highest energy levels (2800 kcal/kg diet) but significantly higher than that obtained on the lowest energy level (2400 kcal/kg diet). Egg weights, Haugh units, feed per dozen eggs, and mortality were not significantly affected by energy levels. In spite of the average maximum monthly temperatures, ranging from 26.8 to 35.2 C, annual egg production was about 71 to 73% for the best groups, figures comparable with those obtainable in temperate climates. Egg weight and Haugh units were similar to reported temperate zone values. This experiment supports the use of 16% protein and a metabolizable energy level of 2400 kcal/kg diet for brown egg-type layers.

  13. Charge-changing particle-hole excitation of 16N and 16F nuclei

    NASA Astrophysics Data System (ADS)

    Taqi Al-Bayati, Ali H.; Darwesh, Sarah S.

    2013-12-01

    The nuclear structure of 16N (closed shell + ν - π) and 16F (closed shell + π - ν) nuclei is studied using particle-hole proton-neutron Tamm-Dancoff Approximation pn TDA and particle-hole proton-neutron Random Phase Approximation pn RPA. The particle-hole Hamiltonian of PSD model space is to be diagonalized in the presence of the PSDMWKPN interaction: for P-space the Cohen-Kurath interaction, for SD-space the Wildenthal Interaction, for the coupling matrix elements between P- and SD-spaces the Millener-Kurath interaction is used, spurious components were eliminated with CM contribution. The results containing energy level schemes and electromagnetic transition strength are compared with the available experimental data.

  14. Charge-changing particle-hole excitation of {sup 16}N and {sup 16}F nuclei

    SciTech Connect

    Taqi Al-Bayati, Ali H.; Darwesh, Sarah S.

    2013-12-16

    The nuclear structure of {sup 16}N (closed shell + ν − π) and {sup 16}F (closed shell + π − ν) nuclei is studied using particle-hole proton-neutron Tamm-Dancoff Approximation pn TDA and particle-hole proton-neutron Random Phase Approximation pn RPA. The particle-hole Hamiltonian of PSD model space is to be diagonalized in the presence of the PSDMWKPN interaction: for P-space the Cohen-Kurath interaction, for SD-space the Wildenthal Interaction, for the coupling matrix elements between P- and SD-spaces the Millener-Kurath interaction is used, spurious components were eliminated with CM contribution. The results containing energy level schemes and electromagnetic transition strength are compared with the available experimental data.

  15. String-Corrected Black Holes

    SciTech Connect

    Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund

    2005-02-07

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect -- the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive! The magnitude of this effect is related to the size of the compactification manifold.

  16. When Charged Black Holes Merge

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-08-01

    Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge

  17. Wavelengths, energy levels and hyperfine structure of Mn II and Sc II.

    NASA Astrophysics Data System (ADS)

    Nave, Gillian; Pickering, Juliet C.; Townley-Smith, Keeley I. M.; Hala, .

    2015-08-01

    For many decades, the Atomic Spectroscopy Groups at the National Institute of Standards and Technology (NIST) and Imperial College London (ICL) have measured atomic data of astronomical interest. Our spectrometers include Fourier transform (FT) spectrometers at NIST and ICL covering the region 1350 Å to 5.5 μm and a 10.7-m grating spectrometer at NIST covering wavelengths from 300 - 5000 Å. Sources for these spectra include high-current continuous and pulsed hollow cathode (HCL) lamps, Penning discharges, and sliding spark discharges. Recent work has focused on the measurement and analysis of wavelengths, energy levels, and hyperfine structure (HFS) constants for iron-group elements. The analysis of FT spectra of Cr I, Mn I, and Mn II is being led by ICL and is described in a companion poster [1]. Current work being led by NIST includes the analysis of HFS in Mn II, analysis of Mn II in the vacuum ultraviolet, and a comprehensive analysis of Sc II.Comprehensive HFS constants for Mn II are needed for the interpretation of stellar spectra and incorrect abundances may be obtained when HFS is omitted. Holt et al. [2] have measured HFS constants for 59 levels of Mn II using laser spectroscopy. We used FT spectra of Mn/Ni and Mn/Cu HCLs covering wavelength ranges from 1350 Å to 5.4 μm to confirm 26 of the A constants of Holt et al. and obtain values for roughly 40 additional levels. We aim to obtain HFS constants for the majority of lines showing significant HFS that are observed in chemically-peculiar stars.Spectra of Sc HCLs have been recorded from 1800 - 6700 Å using a vacuum ultraviolet FT spectrometer at NIST. Additional measurements to cover wavelengths above 6700 Å and below 1800 Å are in progress. The spectra are being analyzed by NIST and Alighar Muslim University, India in order to derive improved wavelengths, energy levels, and hyperfine structure parameters.This work was partially supported by NASA, the STFC and PPARC (UK), the Royal Society of the UK

  18. Black-Hole Feedback in Quasars

    NASA Video Gallery

    This animation illustrates how black-hole feedback works in quasars. Dense gas and dust in the center simultaneously fuels the black hole and shrouds it from view. The black-hole wind propels large...

  19. Fear of holes.

    PubMed

    Cole, Geoff G; Wilkins, Arnold J

    2013-10-01

    Phobias are usually described as irrational and persistent fears of certain objects or situations, and causes of such fears are difficult to identify. We describe an unusual but common phobia (trypophobia), hitherto unreported in the scientific literature, in which sufferers are averse to images of holes. We performed a spectral analysis on a variety of images that induce trypophobia and found that the stimuli had a spectral composition typically associated with uncomfortable visual images, namely, high-contrast energy at midrange spatial frequencies. Critically, we found that a range of potentially dangerous animals also possess this spectral characteristic. We argue that although sufferers are not conscious of the association, the phobia arises in part because the inducing stimuli share basic visual characteristics with dangerous organisms, characteristics that are low level and easily computed, and therefore facilitate a rapid nonconscious response.

  20. Regular phantom black holes.

    PubMed

    Bronnikov, K A; Fabris, J C

    2006-06-30

    We study self-gravitating, static, spherically symmetric phantom scalar fields with arbitrary potentials (favored by cosmological observations) and single out 16 classes of possible regular configurations with flat, de Sitter, and anti-de Sitter asymptotics. Among them are traversable wormholes, bouncing Kantowski-Sachs (KS) cosmologies, and asymptotically flat black holes (BHs). A regular BH has a Schwarzschild-like causal structure, but the singularity is replaced by a de Sitter infinity, giving a hypothetic BH explorer a chance to survive. It also looks possible that our Universe has originated in a phantom-dominated collapse in another universe, with KS expansion and isotropization after crossing the horizon. Explicit examples of regular solutions are built and discussed. Possible generalizations include k-essence type scalar fields (with a potential) and scalar-tensor gravity.

  1. Digesting the doughnut hole.

    PubMed

    Joyce, Geoffrey F; Zissimopoulos, Julie; Goldman, Dana P

    2013-12-01

    Despite its success, Medicare Part D has been widely criticized for the gap in coverage, the so-called "doughnut hole". We compare the use of prescription drugs among beneficiaries subject to the coverage gap with usage among beneficiaries who are not exposed to it. We find that the coverage gap does, indeed, disrupt the use of prescription drugs among seniors with diabetes. But the declines in usage are modest and concentrated among higher cost, brand-name medications. Demand for high cost medications such as antipsychotics, antiasthmatics, and drugs of the central nervous system decline by 8-18% in the coverage gap, while use of lower cost medications with high generic penetration such as beta blockers, ACE inhibitors and antidepressants decline by 3-5% after reaching the gap. More importantly, lower adherence to medications is not associated with increases in medical service use. PMID:24308883

  2. Microscopic black holes and cosmic shells

    NASA Astrophysics Data System (ADS)

    Daghigh, Ramin Ghasemzadeh

    In the first part of this thesis the relativistic viscous fluid equations describing the outflow of high temperature matter created via Hawking radiation from microscopic black holes are solved numerically for a realistic equation of state. We focus on black holes with initial temperatures greater than 100 GeV and lifetimes less than 6 days. The spectra of direct photons and photons from π0 decay are calculated for energies greater than 1 GeV. We calculate the diffuse gamma ray spectrum from black holes distributed in our galactic halo. However, the most promising route for their observation is to search for point sources emitting gamma rays of ever-increasing energy. We also calculate the spectra of all three flavors of neutrinos arising from direct emission from the fluid at the neutrino- sphere and from the decay of pions and muons from their decoupling at much larger radii and smaller temperatures for neutrino energies between 1 GeV and the Planck energy. The results for neutrino spectra may be applicable for the last few hours and minutes of the lifetime of a microscopic black hole. In the second part of this thesis the combined field equations of gravity and a scalar field are studied. When a potential for a scalar field has two local minima there arise spherical shell-type solutions of the classical field equations due to gravitational attraction. We establish such solutions numerically in a space which is asymptotically de Sitter. It generically arises when the energy scale characterizing the scalar field potential is much less than the Planck scale. It is shown that the mirror image of the shell appears in the other half of the Penrose diagram. The configuration is smooth everywhere with no physical singularity.* *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation).

  3. Circumnuclear media of quiescent supermassive black holes

    NASA Astrophysics Data System (ADS)

    Generozov, Aleksey; Stone, Nicholas C.; Metzger, Brian D.

    2015-10-01

    We calculate steady-state, one-dimensional hydrodynamic profiles of hot gas in slowly accreting (`quiescent') galactic nuclei for a range of central black hole masses M•, parametrized gas heating rates, and observationally motivated stellar density profiles. Mass is supplied to the circumnuclear medium by stellar winds, while energy is injected primarily by stellar winds, supernovae, and black hole feedback. Analytic estimates are derived for the stagnation radius (where the radial velocity of the gas passes through zero) and the large-scale gas inflow rate, dot{M}, as a function of M• and the gas heating efficiency, the latter being related to the star formation history. We assess the conditions under which radiative instabilities develop in the hydrostatic region near the stagnation radius, both in the case of a single burst of star formation and for the average star formation history predicted by cosmological simulations. By combining a sample of measured nuclear X-ray luminosities, LX, of nearby quiescent galactic nuclei with our results for dot{M}(M_{bullet }), we address whether the nuclei are consistent with accreting in a steady state, thermally stable manner for radiative efficiencies predicted for radiatively inefficiency accretion flows. We find thermally stable accretion cannot explain the short average growth times of low-mass black holes in the local Universe, which must instead result from gas being fed in from large radii, due either to gas inflows or thermal instabilities acting on larger, galactic scales. Our results have implications for attempts to constrain the occupation fraction of upermassive black holes in low-mass galaxies using the mean LX-M• correlation, as well as the predicted diversity of the circumnuclear densities encountered by relativistic outflows from tidal disruption events.

  4. Investigation on Machining Accuracy of Micro-Holes with Ultrasound Disturbed Electrolyte in Electrochemical Machining

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Wang, Yuanzhe; Wang, Yesheng

    In the paper micro-holes are machined in electrochemical machining (ECM) with the passivating electrolyte disturbed by ultrasound. Based on the Faraday's law, theoretical model of the inter-electrode gap and the mechanism of ultrasonic effect are investigated. Moreover experiments on comparison of ECM micro-holes and ultrasonic assisted ECM micro-holes are carried out, and results show that the distribution of the inter-electrode gap and the localization of anodic dissolution are improved with the passivating electrolyte disturbed by ultrasound. Finally precision micro-holes have been obtained successfully.

  5. Production of tidal-charged black holes at the Large Hadron Collider

    SciTech Connect

    Gingrich, Douglas M.

    2010-03-01

    Tidal-charged black hole solutions localized on a three-brane in the five-dimensional gravity scenario of Randall and Sundrum have been known for some time. The solutions have been used to study the decay, and growth, of black holes with initial mass of about 10 TeV. These studies are interesting in that certain black holes, if produced at the Large Hadron Collider, could live long enough to leave the detectors. I examine the production of tidal-charged black holes at the Large Hadron Collider and show that it is very unlikely that they will be produced during the lifetime of the accelerator.

  6. Interior dynamics of neutral and charged black holes

    NASA Astrophysics Data System (ADS)

    Guo, Jun-Qi; Joshi, Pankaj S.

    2015-09-01

    In this paper, we explore the interior dynamics of neutral and charged black holes. Scalar collapses in flat, Schwarzschild, and Reissner-Nordström background geometries are simulated. We examine the dynamics in the vicinities of the central singularity of a Schwarzschild black hole and of the inner horizon of a Reissner-Nordström black hole. In simulating scalar collapses in Schwarzschild and Reissner-Nordström geometries, Kruskal and Kruskal-like coordinates are used, respectively, with the presence of a scalar field being taken into account. It is found that, besides near the inner horizons of Reissner-Nordström and Kerr black holes, mass inflation also takes place near the central singularity in neutral scalar collapse. Approximate analytic expressions for different types of mass inflation are partially obtained via a close interplay between numerical and analytical approaches and an examination of the connections between Schwarzschild black holes, Reissner-Nordström black holes, neutral collapse, and charge scattering. We argue that the mass inflations near the central singularity and the inner horizon are related to the localness of the dynamics in strong gravity regions. This is in accord with the Belinskii, Khalatnikov, and Lifshitz conjecture.

  7. Energy levels distribution in supersaturated silicon with titanium for photovoltaic applications

    SciTech Connect

    Pérez, E. Castán, H.; García, H.; Dueñas, S.; Bailón, L.; Montero, D.; García-Hernansanz, R.; García-Hemme, E.; González-Díaz, G.; Olea, J.

    2015-01-12

    In the attempt to form an intermediate band in the bandgap of silicon substrates to give it the capability to absorb infrared radiation, we studied the deep levels in supersaturated silicon with titanium. The technique used to characterize the energy levels was the thermal admittance spectroscopy. Our experimental results showed that in samples with titanium concentration just under Mott limit there was a relationship among the activation energy value and the capture cross section value. This relationship obeys to the well known Meyer-Neldel rule, which typically appears in processes involving multiple excitations, like carrier capture/emission in deep levels, and it is generally observed in disordered systems. The obtained characteristic Meyer-Neldel parameters were Tmn = 176 K and kTmn = 15 meV. The energy value could be associated to the typical energy of the phonons in the substrate. The almost perfect adjust of all experimental data to the same straight line provides further evidence of the validity of the Meyer Neldel rule, and may contribute to obtain a deeper insight on the ultimate meaning of this phenomenon.

  8. Energy level shifts at the silica/Ru(0001) heterojunction driven by surface and interface dipoles

    DOE PAGES

    Wang, Mengen; Zhong, Jian -Qiang; Kestell, John; Waluyo, Iradwikanari; Stacchiola, Dario J.; Boscoboinik, J. Anibal; Lu, Deyu

    2016-09-12

    Charge redistribution at heterogeneous interfaces is a fundamental aspect of surface chemistry. Manipulating the amount of charges and the magnitude of dipole moments at the interface in a controlled way has attracted tremendous attention for its potential to modify the activity of heterogeneous catalysts in catalyst design. Two-dimensional ultrathin silica films with well-defined atomic structures have been recently synthesized and proposed as model systems for heterogeneous catalysts studies. R. Wlodarczyk et al. (Phys. Rev. B, 85, 085403 (2012)) have demonstrated that the electronic structure of silica/Ru(0001) can be reversibly tuned by changing the amount of interfacial chemisorbed oxygen. Here wemore » carried out systematic investigations to understand the underlying mechanism through which the electronic structure at the silica/Ru(0001) interface can be tuned. As corroborated by both in situ X-ray photoelectron spectroscopy and density functional theory calculations, the observed interface energy level alignments strongly depend on the surface and interfacial charge transfer induced dipoles at the silica/Ru(0001) heterojunction. These observations may help to understand variations in catalytic performance of the model system from the viewpoint of the electronic properties at the confined space between the silica bilayer and the Ru(0001) surface. As a result, the same behavior is observed for the aluminosilicate bilayer, which has been previously proposed as a model system for zeolites.« less

  9. Hysteresis in Carbon Nanotube Transistors: Measurement and Analysis of Trap Density, Energy Level, and Spatial Distribution.

    PubMed

    Park, Rebecca Sejung; Shulaker, Max Marcel; Hills, Gage; Suriyasena Liyanage, Luckshitha; Lee, Seunghyun; Tang, Alvin; Mitra, Subhasish; Wong, H-S Philip

    2016-04-26

    We present a measurement technique, which we call the Pulsed Time-Domain Measurement, for characterizing hysteresis in carbon nanotube field-effect transistors, and demonstrate its applicability for a broad range of 1D and 2D nanomaterials beyond carbon nanotubes. The Pulsed Time-Domain Measurement enables the quantification (density, energy level, and spatial distribution) of charged traps responsible for hysteresis. A physics-based model of the charge trapping process for a carbon nanotube field-effect transistor is presented and experimentally validated using the Pulsed Time-Domain Measurement. Leveraging this model, we discover a source of traps (surface traps) unique to devices with low-dimensional channels such as carbon nanotubes and nanowires (beyond interface traps which exist in today's silicon field-effect transistors). The different charge trapping mechanisms for interface traps and surface traps are studied based on their temperature dependencies. Through these advances, we are able to quantify the interface trap density for carbon nanotube field-effect transistors (∼3 × 10(13) cm(-2) eV(-1) near midgap), and compare this against a range of previously studied dielectric/semiconductor interfaces.

  10. Spectrum and energy levels of the Yb4+ free ion (Yb V)

    NASA Astrophysics Data System (ADS)

    Meftah, Ali; Wyart, Jean-François; Tchang-Brillet, Wan-Ü. Lydia; Blaess, Christophe; Champion, Norbert

    2013-10-01

    The spectrum of ionized ytterbium produced by a sliding spark source was recorded on the 10 m high resolution vacuum ultraviolet normal-incidence spectrograph of the Meudon Observatory. About 1080 lines attributed to Yb V, hitherto unknown, have been identified. The analysis of this spectrum established all the energy levels of the ground configuration 4f12 and, respectively 174, 12 and 43 levels of the excited configurations 4f115d,4f116s and 4f116p. The theoretical calculations by means of the Cowan codes included a least-squares optimization of the relevant radial parameters by minimizing the differences between calculated and experimental level energies, which led to mean errors of 55 cm-1 for the 56 even parity levels and 51 cm-1 for the 186 odd parity ones. Interactions with the unknown core-excited configurations 5p54f13, 5p54f126p, 5p54f125d and 5p54f126s were taken into account.

  11. Fine-structure energy levels and autoionizing width calculations of magnesium-like Ni XVII

    NASA Astrophysics Data System (ADS)

    Liang, Liang; Gao, Wenjing; Zhou, Chao; Zhang, Ling

    2013-05-01

    We have calculated highly excited fine-structure energy levels and their autoionizing width of 3 pns 3 P 1 ( n = 11-26), 3 pns 1 P 1 ( n = 10-22), 3 pnd 3 D 1 ( n = 11-26), 3 pnd 3 P 1 ( n = 10-21), 3 pnd 1 P 1( n = 10-21), 3 dnp 3 D 1 ( n = 7-30), 3 dnp 3 P 1 ( n = 7-28), 3 dnp 1 P 1 ( n = 7-28), 3 dnf 3 D 1 ( n = 7, 9-27), 3 dnf 3 P 1 ( n = 7, 9-27), and 3 dnf 1 P 1 ( n = 7, 9-27) for magnesium-like Ni XVII. The calculations are based upon the relativistic Breit-Pauli R-matrix approximation combining with the QB method of Quigley-Berrington (L. Quigley, K. A. Berrington, Pelan J. Comput. Phys. Commun. 114, 225 (1998)). We have reported the many unpublished energy values and autoionizing width of the J = 1 odd states of magnesium-like Ni XVII.

  12. Dynamical image-charge effect in molecular tunnel junctions: Beyond energy level alignment

    NASA Astrophysics Data System (ADS)

    Jin, Chengjun; Thygesen, Kristian S.

    2014-01-01

    When an electron tunnels between two metal contacts it temporarily induces an image charge (IC) in the electrodes which acts back on the tunneling electron. It is usually assumed that the IC forms instantaneously such that a static model for the image potential applies. Here we investigate how the finite IC formation time affects charge transport through a molecule suspended between two electrodes. For a single-level model, an analytical treatment shows that the conductance is suppressed by a factor Z2, where Z is the quasiparticle renormalization factor, compared to the static IC approximation. We show that Z can be expressed either in terms of the plasma frequency of the electrode or as the overlap between electrode wave functions corresponding to an empty and filled level, respectively. First-principles GW calculations for benzene-diamine connected to gold electrodes show that the dynamical corrections can reduce the conductance by more than a factor of two when compared to static GW or density functional theory where the molecular energy levels have been shifted to match the exact quasiparticle levels.

  13. Conjugated polymer energy level shifts in lithium-ion battery electrolytes.

    PubMed

    Song, Charles Kiseok; Eckstein, Brian J; Tam, Teck Lip Dexter; Trahey, Lynn; Marks, Tobin J

    2014-11-12

    The ionization potentials (IPs) and electron affinities (EAs) of widely used conjugated polymers are evaluated by cyclic voltammetry (CV) in conventional electrochemical and lithium-ion battery media, and also by ultraviolet photoelectron spectroscopy (UPS) in vacuo. By comparing the data obtained in the different systems, it is found that the IPs of the conjugated polymer films determined by conventional CV (IPC) can be correlated with UPS-measured HOMO energy levels (EH,UPS) by the relationship EH,UPS = (1.14 ± 0.23) × qIPC + (4.62 ± 0.10) eV, where q is the electron charge. It is also found that the EAs of the conjugated polymer films measured via CV in conventional (EAC) and Li(+) battery (EAB) media can be linearly correlated by the relationship EAB = (1.07 ± 0.13) × EAC + (2.84 ± 0.22) V. The slopes and intercepts of these equations can be correlated with the dielectric constants of the polymer film environments and the redox potentials of the reference electrodes, as modified by the surrounding electrolyte, respectively.

  14. Energy levels, transition probabilities, and electron impact excitations for La XXX

    SciTech Connect

    Zhong, J.Y. . E-mail: jyzhong@aphy.iphy.ac.cn; Zhao, G.; Zhang, J.

    2006-09-15

    energy levels, spontaneous radiative decay rates, and electron impact collision strengths are calculated for La XXX. The data refer to 107 fine-structure levels belonging to the configurations (1s{sup 2}2s{sup 2}2p{sup 6})3s{sup 2}3p{sup 6}3d{sup 10}, 3s{sup 2}3p{sup 6}3d{sup 9}4l, 3s{sup 2}3p{sup 5}3d{sup 10}4l, and 3s3p{sup 6}3d{sup 10}4l (l = s, p, d, f). The collision strengths are calculated with a 20-collision-energy grid in terms of the energy of the scattered electron between 10 and 10,000 eV by using the distorted-wave approximation. Effective collision strengths are obtained at seven electron temperatures: T {sub e} (eV) = 10, 100, 300, 500, 800, 1000, and 1500 by integrating the collision strengths over a Maxwellian electron distribution. Coupled with these atomic data, a hydrodynamic code MED103 can be used to simulate the Ni-like La X-ray laser at 8.8 nm.

  15. a New Method for Solving the Z > 137 Problem and for Determination of Energy Levels of Hydrogen-Like Atoms

    NASA Astrophysics Data System (ADS)

    Neznamov, V. P.; Safronov, I. I.

    The "catastrophe" in solving the Dirac equation for an electron in the field of a point electric charge, which emerges for the charge numbers Z > 137, is removed in this work by new method of accounting of finite dimensions of nuclei. For this purpose, in numerical solutions of equations for Dirac radial wave functions, we introduce a boundary condition at the nucleus boundary such that the components of the electron current density is zero. As a result, for all nuclei of the periodic table the calculated energy levels practically coincide with the energy levels in standard solutions of the Dirac equation in the external field of the Coulomb potential of a point charge. Further, for Z > 105, the calculated energy level functions E(Z) are monotone and smooth. The lower energy level reaches the energy E = -mc2 (the electron "drop" on a nuclei) at Zc = 178. The proposed method of accounting of the finite size of nuclei can be easily used in numerical calculations of energy levels of many-electron atoms.

  16. Investigation of Spiral and Sweeping Holes

    NASA Technical Reports Server (NTRS)

    Thurman, Douglas; Poinsatte, Philip; Ameri, Ali; Culley, Dennis; Raghu, Surya; Shyam, Vikram

    2015-01-01

    Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing rations of 1.0, 1.5, 2.0, and 2.5 at a density ration of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.

  17. Investigation of hole injection enhancement by MoO{sub 3} buffer layer in organic light emitting diodes

    SciTech Connect

    Haitao, Xu; Xiang, Zhou

    2013-12-28

    An MoO{sub 3} buffer layer prepared by thermal evaporation as hole injection layer was investigated in organic light emitting diodes. The MoO{sub 3} film inserted between the anode and hole transport layer decreased the operating voltage and enhanced power efficiency. Introduction of 1 nm MoO{sub 3} film, which was found to be the optimum layer thickness, resulted in 45% increase in efficiency compared with traditional ITO anode. Results from atomic force microscopy and photoemission spectroscopy showed that smooth surface morphology and suitable energy level alignment of ITO/MoO{sub 3} interface facilitated hole injection and transport. The hole injection and transport mechanism at the ITO/MoO{sub 3} interface in thin and thick buffer layers were analyzed.

  18. The normal state Hall effect in Nd 1-2 xCa xM xBa 2Cu 3O 7- δ (M = Pr, Th): Evidence for hole localization by disorder

    NASA Astrophysics Data System (ADS)

    Ghorbani, S. R.; Andersson, M.; Rapp, Ö.

    2005-08-01

    The transport properties of sintered samples of Nd1-2xCaxMxBa2Cu3O7-δ (M = Pr, Th) with 0 ⩽ x ⩽ 0.10 have been studied in the normal state by Hall effect measurements. The Hall coefficient at high temperature was almost constant for Ca-Pr while it increased with increasing Ca-Th doping concentration. The results for the Hall coefficient as a function of temperature and doping concentration were analyzed within two different models. A good agreement between models and data was obtained. On the basis of these models, it was inferred that Ca-Pr and Ca-Th doping introduce electronic disorder in the CuO2 planes. The localization tendency is driven by electronic disorder. This is the main reason for strong depression of the superconducting critical temperature in both alloys. It was found that the Hall angle is proportional to T2 in the whole measured temperature range in Ca-Pr doped samples while there are deviations at high temperature in the Ca-Th doped series. In a phenomenological narrow band model, the conduction band was asymmetric for the pure sample and this asymmetry decreased with increasing Ca-Th doping while it was almost constant for Ca-Pr doped samples.

  19. Myers-Perry black hole in an external gravitational field

    NASA Astrophysics Data System (ADS)

    Abdolrahimi, Shohreh; Kunz, Jutta; Nedkova, Petya

    2015-03-01

    We obtain a new exact solution of the 5D Einstein equations in vacuum describing a distorted Myers-Perry black hole with a single angular momentum. Locally, the solution is interpreted as a black hole distorted by a stationary U (1 )×U (1 ) symmetric distribution of external matter. Technically, the solution is constructed by applying a twofold Bäcklund transformation on a 5D distorted Minkowski spacetime as a seed. The physical quantities of the solution are calculated, and a local Smarr-like relation on the black hole horizon is derived. It possesses the same form as the Smarr-like relation for the asymptotically flat Myers-Perry black hole. It is demonstrated that in contrast to the asymptotically flat Myers-Perry black hole, the ratio of the horizon angular momentum and the mass J2/M3 is unbounded, and can grow arbitrarily large. We study the properties of the ergoregion and the horizon surface. The external field does not influence the horizon topology. The horizon geometry however is distorted, and any regular axisymmetric geometry is possible.

  20. Dancing around the Black Hole

    NASA Astrophysics Data System (ADS)

    2001-08-01

    , however, and will soon disrupt. At some moment, many of those young stars may get too close to the monster in the centre and suffer an unhappy fate... PR Photo 25a/01 : The active galaxy NGC 1097 (R-band image) PR Photo 25b/01 : The active galaxy NGC 1808 (H-band image) PR Photo 25c/01 : The active galaxy NGC 5728 (K-band image) PR Photo 25d/01 : Schematic drawing of the various structural components mentioned in the text. PR Photo 25e/01 : ISAAC spectrum (2.3 µm) of the central region of NGC 1808 PR Photo 25f/01 : Stellar motions at the centre of NGC 1808 Central black holes in galaxies ESO PR Photo 25a/01 ESO PR Photo 25a/01 [Preview - JPEG: 400 x 489 pix - 39k] [Normal - JPEG: 800 x 977 pix - 296k] ESO PR Photo 25b/01 ESO PR Photo 25b/01 [Preview - JPEG: 400 x 499 pix - 40k] [Normal - JPEG: 800 x 997 pix - 168k] ESO PR Photo 25c/01 ESO PR Photo 25c/01 [Preview - JPEG: 400 x 488 pix - 47k] [Normal - JPEG: 800 x 975 pix - 384k] Caption : Photos of three active galaxies that were observed with ISAAC during the present programme. They show NGC 1097 (R-band; Photo 25a/01) and the central areas of NGC 1808 (H-band; Photo 25b/01) and NGC 5728 (K-band; Photo 25c/01). The bar-like structures and the luminous centres where the Black Holes are located are well visible - they are discussed in the text. The distances to these galaxies are approximately 55, 35 and 120 million light-years, respectively; the local scales are indicated in the photos. Technical information about these photos is available below. Recent research with space- and ground-based astronomical telescopes indicate that there are very heavy Black Holes at the centres of most galaxies. There is also general agreement among scientists that many of the closest neighbours of our own Milky Way Galaxy, for example the large spiral Andromeda Galaxy and the peculiar Centaurus A galaxy (cf. ESO PR 04/01 ), do contain central black holes with masses from millions to billions of solar masses [2]. Black Holes have an

  1. More Hidden Black Hole Dangers

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

    Black holes such as GRO J1655-40 form from collapsed stars. When stars at least eight times more massive than our Sun exhaust their fuel supply, they no longer have the energy to support their tremendous bulk. These stars explode as supernovae, blasting their outer envelopes into space. If the core is more than three times the mass of the Sun, it will collapse into a singularity, a single point of infinite density.Although light cannot escape black holes, astronomers can see black holes by virtue of the hot, glowing gas often stolen from a neighboring star that orbits these objects. From our vantage point, the light seems to flicker. The Rossi Explorer has recorded this flickering (called quasiperiodic oscillations, or QPOs) around many black holes. QPOs are produced by gas very near the innermost stable orbit the closest orbit a blob of gas can maintain before falling pell-mell into the black hole. As gas whips around the black hole at near light speed, gravity pulls the gas in one direction, then another, adding to the flickering. The QPO is related to the speed and size of this orbit and the mass of the black hole.

  2. Black Hole Grabs Starry Snack

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Poster Version

    This artist's concept shows a supermassive black hole at the center of a remote galaxy digesting the remnants of a star. NASA's Galaxy Evolution Explorer had a 'ringside' seat for this feeding frenzy, using its ultraviolet eyes to study the process from beginning to end.

    The artist's concept chronicles the star being ripped apart and swallowed by the cosmic beast over time. First, the intact sun-like star (left) ventures too close to the black hole, and its own self-gravity is overwhelmed by the black hole's gravity. The star then stretches apart (middle yellow blob) and eventually breaks into stellar crumbs, some of which swirl into the black hole (cloudy ring at right). This doomed material heats up and radiates light, including ultraviolet light, before disappearing forever into the black hole. The Galaxy Evolution Explorer was able to watch this process unfold by observing changes in ultraviolet light.

    The area around the black hole appears warped because the gravity of the black hole acts like a lens, twisting and distorting light.

  3. New odd-parity high-lying energy levels of the europium atom by resonance ionization spectroscopy

    NASA Astrophysics Data System (ADS)

    Nakhate, S. G.; Razvi, M. A. N.; Bhale, G. L.; Ahmad, S. A.

    1996-04-01

    Odd-parity energy levels of the neutral europium atom (Eu I) have been investigated by employing both single-colour and two-colour stepwise laser excitation using the technique of resonance ionization spectroscopy in a heat-pipe thermionic diode system. Fifty-two new odd-parity energy levels of Eu I have been found in the energy region 40 575 - 43 410 0953-4075/29/8/009/img1. The J values for most of these new energy levels have been assigned unambiguously. In addition to this, 19 odd levels which were reported earlier, in the region of our present study, have also been investigated; the assignments of J values to nine of these levels have been confirmed and four levels, which had no unique J assignments, have been assigned definite J values.

  4. Supermassive black holes do not correlate with galaxy disks or pseudobulges.

    PubMed

    Kormendy, John; Bender, R; Cornell, M E

    2011-01-20

    The masses of supermassive black holes are known to correlate with the properties of the bulge components of their host galaxies. In contrast, they seem not to correlate with galaxy disks. Disk-grown 'pseudobulges' are intermediate in properties between bulges and disks; it has been unclear whether they do or do not correlate with black holes in the same way that bulges do. At stake in this issue are conclusions about which parts of galaxies coevolve with black holes, possibly by being regulated by energy feedback from black holes. Here we report pseudobulge classifications for galaxies with dynamically detected black holes and combine them with recent measurements of velocity dispersions in the biggest bulgeless galaxies. These data confirm that black holes do not correlate with disks and show that they correlate little or not at all with pseudobulges. We suggest that there are two different modes of black-hole feeding. Black holes in bulges grow rapidly to high masses when mergers drive gas infall that feeds quasar-like events. In contrast, small black holes in bulgeless galaxies and in galaxies with pseudobulges grow as low-level Seyfert galaxies. Growth of the former is driven by global processes, so the biggest black holes coevolve with bulges, but growth of the latter is driven locally and stochastically, and they do not coevolve with disks and pseudobulges.

  5. Black Holes and Quasiblack Holes in Einstein-Maxwell Theory

    NASA Astrophysics Data System (ADS)

    Meinel, Reinhard; Breithaupt, Martin; Liu, Yu-Chun

    2015-01-01

    Continuous sequences of asymptotically flat solutions to the Einstein-Maxwell equations describing regular equilibrium configurations of ordinary matter can reach a black hole limit. For a distant observer, the spacetime becomes more and more indistinguishable from the metric of an extreme Kerr-Newman black hole outside the horizon when approaching the limit. From an internal perspective, a still regular but non-asymptotically flat spacetime with the extreme Kerr-Newman near-horizon geometry at spatial infinity forms at the limit. Interesting special cases are sequences of Papapetrou-Majumdar distributions of electrically counterpoised dust leading to extreme Reissner-Nordström black holes and sequences of rotating uncharged fluid bodies leading to extreme Kerr black holes.

  6. Black holes and Higgs stability

    NASA Astrophysics Data System (ADS)

    Tetradis, Nikolaos

    2016-09-01

    We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.

  7. Black Holes: A Traveler's Guide

    NASA Astrophysics Data System (ADS)

    Pickover, Clifford A.

    1998-03-01

    BLACK HOLES A TRAVELER'S GUIDE Clifford Pickover's inventive and entertaining excursion beyond the curves of space and time. "I've enjoyed Clifford Pickover's earlier books . . . now he has ventured into the exploration of black holes. All would-be tourists are strongly advised to read his traveler's guide." -Arthur C. Clarke. "Many books have been written about black holes, but none surpass this one in arousing emotions of awe and wonder towards the mysterious structure of the universe." -Martin Gardner. "Bucky Fuller thought big. Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." -Wired. "The book is fun, zany, in-your-face, and refreshingly addictive." -Times Higher Education Supplement.

  8. Quantum mechanics of black holes.

    PubMed

    Witten, Edward

    2012-08-01

    The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely.

  9. Orbital resonances around black holes.

    PubMed

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  10. Thermodynamics of Lifshitz black holes

    NASA Astrophysics Data System (ADS)

    Devecioǧlu, Deniz Olgu; Sarıoǧlu, Özgür

    2011-06-01

    We apply the recently extended conserved Killing charge definition of Abbott-Deser-Tekin formalism to compute, for the first time, the energies of analytic Lifshitz black holes in higher dimensions. We then calculate the temperature and the entropy of this large family of solutions, and study and discuss the first law of black hole thermodynamics. Along the way we also identify the possible critical points of the relevant quadratic curvature gravity theories. Separately, we also apply the generalized Killing charge definition to compute the energy and the angular momentum of the warped AdS3 black hole solution of the three-dimensional new massive gravity theory.

  11. Orbital resonances around black holes.

    PubMed

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here. PMID:25768747

  12. Gravitational polarizability of black holes

    SciTech Connect

    Damour, Thibault; Lecian, Orchidea Maria

    2009-08-15

    The gravitational polarizability properties of black holes are compared and contrasted with their electromagnetic polarizability properties. The 'shape' or 'height' multipolar Love numbers h{sub l} of a black hole are defined and computed. They are then compared to their electromagnetic analogs h{sub l}{sup EM}. The Love numbers h{sub l} give the height of the lth multipolar 'tidal bulge' raised on the horizon of a black hole by faraway masses. We also discuss the shape of the tidal bulge raised by a test-mass m, in the limit where m gets very close to the horizon.

  13. Evaporation of primordial black holes

    NASA Astrophysics Data System (ADS)

    Hawking, S. W.

    The usual explanation of the isotropy of the universe is that inflation would have smoothed out any inhomogeneities. However, if the universe was initially fractal or in a foam like state, an overall inflation would have left it in the same state. I suggest that the universe did indeed begin with a tangled web of wormholes connecting pairs of black holes but that the inflationary expansion was unstable: wormholes that are slightly smaller correspond to black holes that are hotter than the cosmological background and evaporate away. This picture is supported by calculations with Raphael Bousso of the evaporation of primordial black holes in the s-wave and large N approximations.

  14. Quantum mechanics of black holes.

    PubMed

    Witten, Edward

    2012-08-01

    The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely. PMID:22859480

  15. Rotating regular black hole solution

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon

    2016-07-01

    Based on the Newman-Janis algorithm, the Ayón-Beato-García spacetime metric [Phys. Rev. Lett. 80, 5056 (1998)] of the regular spherically symmetric, static, and charged black hole has been converted into rotational form. It is shown that the derived solution for rotating a regular black hole is regular and the critical value of the electric charge for which two horizons merge into one sufficiently decreases in the presence of the nonvanishing rotation parameter a of the black hole.

  16. Energy level structure of 4f5d states and the Stokes shift in LaPO4:Pr3+ : A theoretical study

    NASA Astrophysics Data System (ADS)

    Bagatur'Yants, A. A.; Iskandarova, I. M.; Knizhnik, A. A.; Mironov, V. S.; Potapkin, B. V.; Srivastava, A. M.; Sommerer, T. J.

    2008-10-01

    The energy levels and the Stokes shift of the excited 4f15d1 states of Pr3+ ions doped into LaPO4 are calculated using a combined theoretical approach. The local structure of the rare-earth site in LaPO4 is obtained from first-principles calculations, while the 4f15d1 states of Pr3+ are treated parametrically in terms of a model Hamiltonian. The crystal-field energies of the 5d electron of a low-symmetry rare-earth site in LaPO4 are obtained from angular-overlap model calculations. First-principles calculations are performed for LaPO4:Ce3+ used as a reference compound for LaPO4:Pr3+ ; the geometry parameters of the rare-earth site are determined for the ground state (4f) and for the excited (5d) state of the central Ce3+ ion. It is shown that the 4f-5d excitation in LaPO4:Ce3+ is accompanied by a strong relaxation of the local structure of the rare-earth site due to rotations of one of the neighboring tetrahedral PO4 phosphate groups: the coordination number of Ce3+ reduces from nine to eight and the average Ce-O distance shortens by about 0.1Å . This leads to a considerably larger crystal-field splitting energy of the 5d states for the excited-state geometry of the cerium site ( ˜17700cm-1 vs ˜12000cm-1 in the ground state) and to a large 5d-4f Stokes shift in LaPO4:Ce3+ ( 3980cm-1 calculated and 4880cm-1 experimental). The 5d crystal-field splitting energies obtained for Ce3+ are then employed for calculations of the 4f15d1 energy levels in LaPO4:Pr3+ . The calculated Stokes shift in LaPO4:Pr3+ is 3610cm-1 . Due to such a large Stokes shift, in an excited Pr3+ ion the lowest 4f15d1 energy level lies below the upper S10(4f2) level, while in an unexcited ion (in the ground 4f2 state) the order of these states is reverse. This fact is responsible for the absence of 4f-4f emission from the S10 state in LaPO4:Pr3+ .

  17. Discrete-hole film cooling characteristics over concave and convex surfaces

    NASA Astrophysics Data System (ADS)

    Ko, Shao-Yen; Yao, Yong-Qing; Xia, Bin; Tsou, Fu-Kang

    The local film-cooling effectiveness and local pressure distribution for single-row discrete holes were measured over the whole areas of concave and convex surfaces, using a plexiglass test section with curvature radii of 140 mm and 70 mm for the concave and the convex surfaces and film-cooling holes (34 on the convex surface and 22 on the concave surface) 8 mm in diameter. The results indicate that the concave surface has the widest film-cooling coverage area in the z-direction (perpendicular to the x-flow direction), while the highest film-cooling effectiveness of the convex surface is near the ejection hole. High blowing ratios at holes have an adverse effect on film cooling. The weakest cooling region is near the center line between holes; such a poorly cooled region is larger on convex surfaces than on the concave ones. Optimal design characteristics for turbine blades surfaces are discussed.

  18. The energy-level crossing behavior and quantum Fisher information in a quantum well with spin-orbit coupling

    PubMed Central

    Wang, Z. H.; Zheng, Q.; Wang, Xiaoguang; Li, Yong

    2016-01-01

    We study the energy-level crossing behavior in a two-dimensional quantum well with the Rashba and Dresselhaus spin-orbit couplings (SOCs). By mapping the SOC Hamiltonian onto an anisotropic Rabi model, we obtain the approximate ground state and its quantum Fisher information (QFI) via performing a unitary transformation. We find that the energy-level crossing can occur in the quantum well system within the available parameters rather than in cavity and circuit quantum eletrodynamics systems. Furthermore, the influence of two kinds of SOCs on the QFI is investigated and an intuitive explanation from the viewpoint of the stationary perturbation theory is given. PMID:26931762

  19. A Critical Compilation of Energy Levels, Spectral Lines, and Transition Probabilities of Singly Ionized Silver, Ag II

    PubMed Central

    Kramida, Alexander

    2013-01-01

    All available experimental measurements of the spectrum of the Ag+ ion are critically reviewed. Systematic shifts are removed from the measured wavelengths. The compiled list of critically evaluated wavelengths is used to derive a comprehensive list of energy levels with well-defined uncertainties. Eigenvector compositions and level designations are found in two alternate coupling schemes. Some of the older work is found to be incorrect. A revised value of the ionization energy, 173283(7) cm−1, equivalent to 21.4844(8) eV, is derived from the new energy levels. A set of critically evaluated transition probabilities is given. PMID:26401429

  20. Energy level alignment in polymer organic solar cells at donor-acceptor planar junction formed by electrospray vacuum deposition

    SciTech Connect

    Kim, Ji-Hoon; Hong, Jong-Am; Kwon, Dae-Gyeon; Seo, Jaewon; Park, Yongsup

    2014-04-21

    Using ultraviolet photoelectron spectroscopy (UPS), we have measured the energy level offset at the planar interface between poly(3-hexylthiophene) (P3HT) and C{sub 61}-butyric acid methylester (PCBM). Gradual deposition of PCBM onto spin-coated P3HT in high vacuum was made possible by using electrospray vacuum deposition (EVD). The UPS measurement of EVD-prepared planar interface resulted in the energy level offset of 0.91 eV between P3HT HOMO and PCBM LUMO, which is considered as the upper limit of V{sub oc} of the organic photovoltaic cells.

  1. Energy levels and far-infrared optical absorption of impurity doped semiconductor nanorings: Intense laser and electric fields effects

    NASA Astrophysics Data System (ADS)

    Barseghyan, M. G.

    2016-11-01

    The effects of electron-impurity interaction on energy levels and far-infrared absorption in semiconductor nanoring under the action of intense laser and lateral electric fields have been investigated. Numerical calculations are performed using exact diagonalization technique. It is found that the electron-impurity interaction and external fields change the energy spectrum dramatically, and also have significant influence on the absorption spectrum. Strong dependence on laser field intensity and electric field of lowest energy levels, also supported by the Coulomb interaction with impurity, is clearly revealed.

  2. Effect of Different Energy Levels of Microwave on Disinfection of Dental Stone Casts

    PubMed Central

    Robati Anaraki, Mahmood; Lotfipour, Farzaneh; Moslehifard, Elnaz; Momtaheni, Ali; Sigari, Pooyan

    2013-01-01

    Background and aims Current chemical methods may not efficiently disinfect dental stone casts. The aim of this study was to investigate if microwave irradiation is effective for disinfection of stone casts. Materials and methods In this laboratory study, three groups (n = 162) of prepared spherical stone beads as carriers with a diameter of 10 mm were inoculated by separately soaking in three broth culture media, each containing a study microorganism—Pseudomonas aeruginosa, Staphylococcus aureus or Candida albicans. Six inoculated carriers were used for every test, including irradiation in a household microwave oven at 300, 450, 600 or 900 W energy level, or soaking in 0.03%, 0.06%, 0.12%, 0.25% or 0.50% concentration of sodium hypochlorite solution, at 1, 2, or 3-minute test times. Positive and negative control groups were considered for each test. All treated carriers were then individually transferred to nutrient broth culture medium and one milliliter from each tube was cultured in nutrient agar media over night. Colony forming unit per milliliter (CFU/mL) was counted, and multi-factor ANOVA was used to analyze data (α = 0.05). Results Microwave irradiation at 600 W resulted in high-level disinfection in 3 minutes. Immersion of the stone casts in hypochlorite solution at 0.06% concentration resulted in disinfection after 2 minutes. Conclusion According to the results, high level disinfection of the stone casts can be achieved by microwave irradiation at 600 W in 3 minutes, similar to a validated chemical method. PMID:24082984

  3. Energy transfer and energy level decay processes in Tm{sup 3+}-doped tellurite glass

    SciTech Connect

    Gomes, Laercio; Lousteau, Joris; Milanese, Daniel; Scarpignato, Gerardo C.; Jackson, Stuart D.

    2012-03-15

    The primary excited state decay and energy transfer processes in singly Tm{sup 3+}-doped TeO{sub 2}:ZnO:Bi{sub 2}O{sub 3}:GeO{sub 2} (TZBG) glass relating to the {sup 3}F{sub 4}{yields}{sup 3}H{sub 6}{approx}1.85 {mu}m laser transition have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the {sup 3}H{sub 4} manifold at 794 nm, the {sup 3}H{sub 5} manifold at 1220 nm, and {sup 3}F{sub 4} manifold at 1760 nm has established that the {sup 3}H{sub 5} manifold is entirely quenched by multiphonon relaxation in tellurite glass. The luminescence from the {sup 3}H{sub 4} manifold with an emission peak at 1465 nm suffers strong suppression due to cross relaxation that populates the {sup 3}F{sub 4} level with a near quadratic dependence on the Tm{sup 3+} concentration. The {sup 3}F{sub 4} lifetime becomes longer as the Tm{sup 3+} concentration increases due to energy migration and decreases to 2.92 ms when [Tm{sup 3+}] = 4 mol. % as a result of quasi-resonant energy transfer to free OH{sup -} radicals present in the glass at concentrations between 1 x 10{sup 18} cm{sup -3} and 2 x 10{sup 18} cm{sup -3}. Judd-Ofelt theory in conjunction with absorption measurements were used to obtain the radiative lifetimes and branching ratios of the energy levels located below 25 000 cm{sup -1}. The spectroscopic parameters, the cross relaxation and Tm{sup 3+}({sup 3}F{sub 4}) {yields} OH{sup -} energy transfer rates were used in a numerical model for laser transitions emitting at 2335 nm and 1865 nm.

  4. Erratic Black Hole Regulates Itself

    NASA Astrophysics Data System (ADS)

    2009-03-01

    New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

  5. Black hole meiosis

    NASA Astrophysics Data System (ADS)

    van Herck, Walter; Wyder, Thomas

    2010-04-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.

  6. Area-angular-momentum inequality for axisymmetric black holes.

    PubMed

    Dain, Sergio; Reiris, Martin

    2011-07-29

    We prove the local inequality A≥8π|J|, where A and J are the area and angular momentum of any axially symmetric closed stable minimal surface in an axially symmetric maximal initial data. From this theorem it is proved that the inequality is satisfied for any surface on complete asymptotically flat maximal axisymmetric data. In particular it holds for marginal or event horizons of black holes. Hence, we prove the validity of this inequality for all dynamical (not necessarily near equilibrium) axially symmetric black holes.

  7. A new instability of the topological black hole

    NASA Astrophysics Data System (ADS)

    Belin, Alexandre; Maloney, Alexander

    2016-11-01

    We investigate the stability of massless topological black holes in {{{AdS}}}d when minimally coupled to a scalar field of negative mass-squared. In many cases such black holes are unstable even though the field is above the BF bound and the geometry is locally AdS. The instability depends on the choice of boundary conditions for the scalars: scalars with non-standard (Neumann) boundary conditions tend to be more unstable, though scalars with standard (Dirichlet) boundary conditions can be unstable as well. This leads to an apparent mismatch between boundary and bulk results in the Vasiliev/vector-like matter duality.

  8. Borehole cylindrical noise during hole-surface and hole-hole resistivity measurements

    NASA Astrophysics Data System (ADS)

    Osiensky, James L.; Nimmer, Robin; Binley, Andrew M.

    2004-04-01

    Drilled boreholes generally are the only feasible means to access the subsurface for the emplacement of downhole electrodes for most hole-hole and hole-surface resistivity experiments. However, the very existence of the borehole itself creates the potential for significant noise due to the inevitable conductivity contrast that develops between the borehole walls and the formation. Borehole cylindrical noise develops whenever a current source is placed in a drilled borehole. Borehole geometries may range from nearly perfect cylinders to highly, irregular, rugose holes in consolidated rock, to relatively minor, collapsed, disturbed zones in caving sediments. Boreholes in non-caving formations generally are filled with artificial, conductive materials to afford crucial, electrical continuity between downhole electrodes and the borehole walls. Filled boreholes form cylindrically shaped heterogeneities that create significant noise due to preferential current flow up and down the conductive columns. Selected conditions are simulated with a finite difference model to illustrate the significance of borehole cylindrical noise on hole-hole and hole-surface mise-à-la-masse electrical potentials near a current electrode. Mise-à-la-masse electrical potentials measured during a field tracer experiment also are presented. These measurements are used to illustrate significant errors may develop in the interpretation of apparent resistivity estimates out to a distance of several meters from the current source if borehole cylindrical noise is not recognized and accounted for in the analysis of electrical potential data.

  9. Flame hole dynamics simulation of Sandia Flame F

    NASA Astrophysics Data System (ADS)

    Knaus, Robert; Hewson, John; Domino, Stefan; Pantano, Carlos

    2014-11-01

    The Sandia Flame ``F'' is a piloted methane/air diffusion flame containing high levels of local extinction. These regions of local extinction reduce the efficiency of combustion and can increase the production of certain pollutants (e.g. carbon monoxide) as well as limit the overall stability of the flame. We present a flame hole dynamics model describing evolution of local extinction zones (flame holes) in a turbulent diffusion flame and apply it to perform a direct numerical simulation of the Sandia Flame F using Sandia's ``SIERRA low Mach Module, Nalu.'' The flame hole dynamics model is a phase-field model that describes the state of the flame (burning or extinguished) through a surface partial differential equation modeling extinction, reignition and advection of the flame state on the moving stoichiometric surface using edge flame properties. The solution of the surface equation is then extended away from the surface and used for state evaluations using a flamelet library with steady flamelets in the burning region and a transient solution in the quenched regions. The flame hole dynamics approach allows tracking extinction and reignition in turbulent diffusion flames without using the computationally costly detailed chemistry explicitly.

  10. Summary of Magnetic Holes Project

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Magnetic Holes in the solar wind are anomalous decreases in the interplanetary magnetic field as measured at a particular spacecraft. Such signatures have been observed in durations of several hours all the way down to the time resolution of the fastest magnetometer instruments, and with magnetic field decreases anywhere from a few percent to nearly full annihilation. It has been an objective of this study to implement a general strategy for detecting magnetic holes on all scales at which they can be found. Investigations into the properties of magnetic holes began with collections of events appearing distinct to the naked eye, perhaps biased by morphological characteristics or suggestive density and temperature fluctuations. More recent studies have taken the simple approach of cataloging any time period wherein the magnetic field is reduced by more than half. This investigation takes a statistical approach to the problem of identifying real magnetic hole events at all available scales.

  11. 'Black holes': escaping the void.

    PubMed

    Waldron, Sharn

    2013-02-01

    The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche.

  12. Black hole accretion disc impacts

    NASA Astrophysics Data System (ADS)

    Pihajoki, P.

    2016-04-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength λ = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  13. The Black Hole Universe Model

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  14. Black holes: fundamentals and controversies

    NASA Astrophysics Data System (ADS)

    Romero, G. E.

    2016-08-01

    Black holes are fully gravitational collapsed objects. They have been studied from a theoretical point of view during more than 40 years using the theory of General Relativity. Recently they have been also investigated in the context of alternative theories of gravitation. In this paper I review the main properties of black holes and I discuss, in an accesible way, some recent controversies about the nature of these objects.

  15. Sputtering Holes with Ion Beamlets

    NASA Technical Reports Server (NTRS)

    Byers, D. C.; Banks, B. A.

    1974-01-01

    Ion beamlets of predetermined configurations are formed by shaped apertures in the screen grid of an ion thruster having a double grid accelerator system. A plate is placed downstream from the screen grid holes and attached to the accelerator grid. When the ion thruster is operated holes having the configuration of the beamlets formed by the screen grid are sputtered through the plate at the accelerator grid.

  16. Black holes as parts of entangled systems

    NASA Astrophysics Data System (ADS)

    Basini, G.; Capozziello, S.; Longo, G.

    A possible link between EPR-type quantum phenomena and astrophysical objects like black holes, under a new general definition of entanglement, is established. A new approach, involving backward time evolution and topology changes, is presented bringing to a definition of the system black hole-worm hole-white hole as an entangled system.

  17. Revisiting mask contact hole measurements

    NASA Astrophysics Data System (ADS)

    Higuchi, Masaru; Gallagher, Emily; Ceperley, Daniel; Brunner, Timothy; Bowley, Reg; McGuire, Anne

    2006-10-01

    Contact holes represent one of the biggest critical dimension (CD) mask metrology challenges for 45nm technology mask development. The challenge is a consequence of both wafer and mask sensitivities. Large mask error factors and the small process windows found when contact holes are imaged on wafers impose very tight mask specifications for CD uniformity. The resultant CD error budget leaves little room for mask metrology. Current advanced mask metrology deploys a CD-SEM to characterize the mask contact hole CD uniformity. Measuring a contact hole is complex since it is inherently two-dimensional and is not always well-characterized by one-dimensional x- and y-axis measurements. This paper will investigate contact metrics such as line edge roughness (LER), region of interest (ROI) size, area, and CD sampling methods. The relative merits of each will be explored. Ultimately, an understanding of the connection between what is physically measured on the mask and what impacts wafer imaging must be understood. Simulations will be presented to explore the printability of a contact hole's physical attributes. The results will be summarized into a discussion of optimal contact hole metrology for 45nm technology node masks.

  18. The 2002 Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, P. A.; Nash, E. R.; Douglass, A. R.; Kawa, S. R.

    2003-01-01

    Since 1979, the ozone hole has grown from near zero size to over 24 Million km2. This area is most strongly controlled by levels of inorganic chlorine and bromine oncentrations. In addition, dynamical variations modulate the size of the ozone hole by either cooling or warming the polar vortex collar region. We will review the size observations, the size trends, and the interannual variability of the size. Using a simple trajectory model, we will demonstrate the sensitivity of the ozone hole to dynamical forcing, and we will use these observations to discuss the size of the ozone hole during the 2002 Austral spring. We will further show how the Cly decreases in the stratosphere will cause the ozone hole to decrease by 1-1.5% per year. We will also show results from a 3-D chemical transport model (CTM) that has been continuously run since 1999. These CTM results directly show how strong dynamics acts to reduce the size of the ozone hole.

  19. Additions to the spectra and energy levels of the zinc-like ions Y X-Cd XIX

    NASA Astrophysics Data System (ADS)

    Litzén, Ulf; Hansson, Anna

    1989-10-01

    Transitions from 4p4d 1F and 3F have been identified in the spectra Y X-Cd XIX emitted from laserproduced plasmas. Energy levels have been derived, and the term structure has been studied with special emphasis on the 4s4f-4p4d configuration interaction.

  20. Close encounters of three black holes

    SciTech Connect

    Campanelli, Manuela; Lousto, Carlos O.; Zlochower, Yosef

    2008-05-15

    We present the first fully relativistic long-term numerical evolutions of three equal-mass black holes in a system consisting of a third black hole in a close orbit about a black-hole binary. These close-three-black-hole systems have very different merger dynamics from black-hole binaries; displaying complex trajectories, a redistribution of energy that can impart substantial kicks to one of the holes, distinctive waveforms, and suppression of the emitted gravitational radiation. In one configuration the binary is quickly disrupted and the individual holes follow complicated trajectories and merge with the third hole in rapid succession, while in another, the binary completes a half-orbit before the initial merger of one of the members with the third black hole, and the resulting two-black-hole system forms a highly elliptical, well separated binary that shows no significant inspiral for (at least) the first t{approx}1000M of evolution.

  1. Quantum mechanics on a Möbius ring: Energy levels, symmetry, optical transitions, and level splitting in a magnetic field

    NASA Astrophysics Data System (ADS)

    Li, Zehao; Ram-Mohan, L. R.

    2012-05-01

    We investigate the quantum mechanical energy levels of an electron constrained to motion on a nanoscale Möbius ring by solving the Schrödinger equation on the curved surface. The dimensions of the ring in terms of the lateral and transverse parameters {u,v} for the Möbius ring allow us to identify the quantum numbers for the levels by (nu,nv). We show that the energy levels can still be labeled using the quantum numbers of the cylindrical ring of the same dimensions. While the Hamiltonian has invariance under parity in parameter space, the rotational symmetry about any axis in configuration space is lost, so that the double degeneracy of energy levels for azimuthal quantum number nu≥1, that exists in cylindrical rings, is lifted by a small amount in the Möbius ring. The pattern of level splitting has been identified in terms of the number of twists σ to be 2nu=sσ where s is an integer. The scaling properties of the energy levels with respect to the dimensions of the ring are derived; using these properties, our numerical results which are given for a specific geometry can be extended to rings of other commensurate dimensions. The absence of rotational invariance for the Möbius ring manifests itself through the orbital angular momentum Lz not commuting with the Hamiltonian. Its expectation values are found to have nearly integral as well as half-integral values of ℏ, and its variances are small. The energy levels with half-integral azimuthal quantum numbers (nu) are also close to the approximate formula for the equivalent cylindrical ring, provided such half-integral quantum numbers are allowed for the cylindrical geometry. The Zeeman splitting of the energy levels in an external magnetic field is displayed, together with wave functions at a level anticrossing. The optical transitions between electronic states on the Möbius ring are obtained, and a table of oscillator strengths is provided. The results for energy levels for rings with multiple twists are

  2. Erratic Black Hole Regulates Itself

    NASA Astrophysics Data System (ADS)

    2009-03-01

    New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

  3. Numerical Relativity Simulations for Black Hole Merger Astrophysics

    NASA Technical Reports Server (NTRS)

    Baker, John G.

    2010-01-01

    Massive black hole mergers are perhaps the most energetic astronomical events, establishing their importance as gravitational wave sources for LISA, and also possibly leading to observable influences on their local environments. Advances in numerical relativity over the last five years have fueled the development of a rich physical understanding of general relativity's predictions for these events. Z will overview the understanding of these event emerging from numerical simulation studies. These simulations elucidate the pre-merger dynamics of the black hole binaries, the consequent gravitational waveform signatures ' and the resulting state, including its kick velocity, for the final black hole produced by the merger. Scenarios are now being considered for observing each of these aspects of the merger, involving both gravitational-wave and electromagnetic astronomy.

  4. Black Holes at the Centers of Nearby Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Moran, Edward

    2011-09-01

    As part of a search for intermediate-mass black holes in the local universe, we have assembled a sample of 27 AGNs in dwarf galaxies with absolute magnitudes as faint as -15.5 and stellar masses as low as 4e8 M_sun. Collectively, these are the least massive galaxies known to contain central black holes. Surprisingly, 25 of the objects are narrow-line (type 2) AGNs. As such, they are important in the context of theoretical work, which suggests that at low luminosites AGNs may lack obscuring tori and/or classical broad-line regions. X-ray data will indicate directly whether the AGNs are obscured. The data will also afford measurements of their high-energy luminosities, which will anchor their spectral energy distributions and provide constraints on their black-hole masses.

  5. Quantum state of the black hole interior

    NASA Astrophysics Data System (ADS)

    Brustein, Ram; Medved, A. J. M.

    2015-08-01

    If a black hole (BH) is initially in an approximately pure state and it evaporates by a unitary process, then the emitted radiation will be in a highly quantum state. As the purifier of this radiation, the state of the BH interior must also be in some highly quantum state. So that, within the interior region, the mean-field approximation cannot be valid and the state of the BH cannot be described by some semiclassical metric. On this basis, we model the state of the BH interior as a collection of a large number of excitations that are packed into closely spaced but single-occupancy energy levels; a sort-of "Fermi sea" of all light-enough particles. This highly quantum state is surrounded by a semiclassical region that lies close to the horizon and has a non-vanishing energy density. It is shown that such a state looks like a BH from the outside and decays via gravitational pair production in the near-horizon region at a rate that agrees with the Hawking rate. We also consider the fate of a classical object that has passed through to the BH interior and show that, once it has crossed over the near-horizon threshold, the object meets its demise extremely fast. This result cannot be attributed to a "firewall", as the trauma to the in-falling object only begins after it has passed through the near-horizon region and enters a region where semiclassical spacetime ends but the energy density is still parametrically smaller than Planckian.

  6. Fine-structure calculations of energy levels, oscillator strengths, and transition probabilities for sulfur-like iron, Fe XI

    SciTech Connect

    Abou El-Maaref, A.; Ahmad, Mahmoud; Allam, S.H.

    2014-05-15

    Energy levels, oscillator strengths, and transition probabilities for transitions among the 14 LS states belonging to configurations of sulfur-like iron, Fe XI, have been calculated. These states are represented by configuration interaction wavefunctions and have configurations 3s{sup 2}3p{sup 4}, 3s3p{sup 5}, 3s{sup 2}3p{sup 3}3d, 3s{sup 2}3p{sup 3}4s, 3s{sup 2}3p{sup 3}4p, and 3s{sup 2}3p{sup 3}4d, which give rise to 123 fine-structure energy levels. Extensive configuration interaction calculations using the CIV3 code have been performed. To assess the importance of relativistic effects, the intermediate coupling scheme by means of the Breit–Pauli Hamiltonian terms, such as the one-body mass correction and Darwin term, and spin–orbit, spin–other-orbit, and spin–spin corrections, are incorporated within the code. These incorporations adjusted the energy levels, therefore the calculated values are close to the available experimental data. Comparisons between the present calculated energy levels as well as oscillator strengths and both experimental and theoretical data have been performed. Our results show good agreement with earlier works, and they might be useful in thermonuclear fusion research and astrophysical applications. -- Highlights: •Accurate atomic data of iron ions are needed for identification of solar corona. •Extensive configuration interaction wavefunctions including 123 fine-structure levels have been calculated. •The relativistic effects by means of the Breit–Pauli Hamiltonian terms are incorporated. •This incorporation adjusts the energy levels, therefore the calculated values are close to experimental values.

  7. Black holes, information, and Hilbert space for quantum gravity

    NASA Astrophysics Data System (ADS)

    Nomura, Yasunori; Varela, Jaime; Weinberg, Sean J.

    2013-04-01

    A coarse-grained description for the formation and evaporation of a black hole is given within the framework of a unitary theory of quantum gravity preserving locality, without dropping the information that manifests as macroscopic properties of the state at late times. The resulting picture depends strongly on the reference frame one chooses to describe the process. In one description based on a reference frame in which the reference point stays outside the black hole horizon for sufficiently long time, a late black hole state becomes a superposition of black holes in different locations and with different spins, even if the back hole is formed from collapsing matter that had a well-defined classical configuration with no angular momentum. The information about the initial state is partly encoded in relative coefficients—especially phases—of the terms representing macroscopically different geometries. In another description in which the reference point enters into the black hole horizon at late times, an S-matrix description in the asymptotically Minkowski spacetime is not applicable, but it still allows for an “S-matrix” description in the full quantum gravitational Hilbert space including singularity states. Relations between different descriptions are given by unitary transformations acting on the full Hilbert space, and they in general involve superpositions of “distant” and “infalling” descriptions. Despite the intrinsically quantum mechanical nature of the black hole state, measurements performed by a classical physical observer are consistent with those implied by general relativity. In particular, the recently-considered firewall phenomenon can occur only for an exponentially fine-tuned (and intrinsically quantum mechanical) initial state, analogous to an entropy decreasing process in a system with large degrees of freedom.

  8. Charged rotating black holes on a 3-brane

    SciTech Connect

    Aliev, A.N.; Guemruekcueoglu, A.E.

    2005-05-15

    We study exact stationary and axisymmetric solutions describing charged rotating black holes localized on a 3-brane in the Randall-Sundrum braneworld. The charges of the black holes are considered to be of two types, the first being an induced tidal charge that appears as an imprint of nonlocal gravitational effects from the bulk space and the second is a usual electric charge arising due to a Maxwell field trapped on the brane. We assume a special ansatz for the metric on the brane taking it to be of the Kerr-Schild form and show that the Kerr-Newman solution of ordinary general relativity in which the electric charge is superseded by a tidal charge satisfies a closed system of the effective gravitational field equations on the brane. It turns out that the negative tidal charge may provide a mechanism for spinning up the black hole so that its rotation parameter exceeds its mass. This is not allowed in the framework of general relativity. We also find a new solution that represents a rotating black hole on the brane carrying both charges. We show that for a rapid enough rotation the combined influence of the rotational dynamics and the local bulk effects of the 'squared' energy-momentum tensor on the brane distort the horizon structure of the black hole in such a way that it can be thought of as composed of nonuniformly rotating null circles with growing radii from the equatorial plane to the poles. We finally study the geodesic motion of test particles in the equatorial plane of a rotating black hole with tidal charge. We show that the effects of negative tidal charge tend to increase the horizon radius, as well as the radii of the limiting photon orbit, the innermost bound and the innermost stable circular orbits for both direct and retrograde motions of the particles.

  9. RF capacitively coupled plasma with multi-hole multi electrode

    NASA Astrophysics Data System (ADS)

    Lee, Hun Su; Lee, Yun Seong; Seo, Sang Hun; Chang, Hong Young

    2011-10-01

    In the photovoltaic industry, it is desired to make plasma discharge of high electron density for the deposition of microcrystalline silicon layer, which is a bottle-neck process in the fabrication of thin film solar cell. So multi-hole electrode instead of plane electrode is used to make capacitively coupled discharge and the deposition rate could be increased because of the plasma density increases by the increased ionization by the energetic secondary electron surrounded by sheath region. To further increase the productivity of the process, high frequency and large electrode area is demanded, however the uniformity of the process is degraded by the change. To solve the matter, the concept of dividing a multi-hole electrode into multiple multi-hole electrode is introduced in the presentation. By dividing electrode into several region and differentiating the hole configuration of each region, local hollow cathode effect can be controlled to make more uniform discharge. To verify the feasibility of the concept, an electrode of RF capacitively coupled plasma is divided and the hole configuration of each electrode. And with 13.56MHz power applied to the electrode, the spatial plasma distribution of the discharge is measured.

  10. Stress Wave Interaction Between Two Adjacent Blast Holes

    NASA Astrophysics Data System (ADS)

    Yi, Changping; Johansson, Daniel; Nyberg, Ulf; Beyglou, Ali

    2016-05-01

    Rock fragmentation by blasting is determined by the level and state of stress in the rock mass subjected to blasting. With the application of electronic detonators, some researchers stated that it is possible to achieve improved fragmentation through stress wave superposition with very short delay times. This hypothesis was studied through theoretical analysis in the paper. First, the stress in rock mass induced by a single-hole shot was analyzed with the assumptions of infinite velocity of detonation and infinite charge length. Based on the stress analysis of a single-hole shot, the stress history and tensile stress distribution between two adjacent holes were presented for cases of simultaneous initiation and 1 ms delayed initiation via stress superposition. The results indicated that the stress wave interaction is local around the collision point. Then, the tensile stress distribution at the extended line of two adjacent blast holes was analyzed for a case of 2 ms delay. The analytical results showed that the tensile stress on the extended line increases due to the stress wave superposition under the assumption that the influence of neighboring blast hole on the stress wave propagation can be neglected. However, the numerical results indicated that this assumption is unreasonable and yields contrary results. The feasibility of improving fragmentation via stress wave interaction with precise initiation was also discussed. The analysis in this paper does not support that the interaction of stress waves improves the fragmentation.

  11. Black holes with gravitational hair in higher dimensions

    SciTech Connect

    Anabalon, Andres; Canfora, Fabrizio; Giacomini, Alex; Oliva, Julio

    2011-10-15

    A new class of vacuum black holes for the most general gravity theory leading to second order field equations in the metric in even dimensions is presented. These space-times are locally anti-de Sitter in the asymptotic region, and are characterized by a continuous parameter that does not enter in the conserve charges, nor it can be reabsorbed by a coordinate transformation: it is therefore a purely gravitational hair. The black holes are constructed as a warped product of a two-dimensional space-time, which resembles the r-t plane of the Banados-Teitelboim-Zanelli black hole, times a warp factor multiplying the metric of a D-2-dimensional Euclidean base manifold, which is restricted by a scalar equation. It is shown that all the Noether charges vanish. Furthermore, this is consistent with the Euclidean action approach: even though the black hole has a finite temperature, both the entropy and the mass vanish. Interesting examples of base manifolds are given in eight dimensions which are products of Thurston geometries, giving then a nontrivial topology to the black hole horizon. The possibility of introducing a torsional hair for these solutions is also discussed.

  12. Black Hole Caught Zapping Galaxy into Existence?

    NASA Astrophysics Data System (ADS)

    2009-11-01

    equivalent to about 350 Suns per year, one hundred times more than rates for typical galaxies in the local Universe. Earlier observations had shown that the companion galaxy is, in fact, under fire: the quasar is spewing a jet of highly energetic particles towards its companion, accompanied by a stream of fast-moving gas. The injection of matter and energy into the galaxy indicates that the quasar itself might be inducing the formation of stars and thereby creating its own host galaxy; in such a scenario, galaxies would have evolved from clouds of gas hit by the energetic jets emerging from quasars. "The two objects are bound to merge in the future: the quasar is moving at a speed of only a few tens of thousands of km/h with respect to the companion galaxy and their separation is only about 22 000 light-years," says Elbaz. "Although the quasar is still 'naked', it will eventually be 'dressed' when it merges with its star-rich companion. It will then finally reside inside a host galaxy like all other quasars." Hence, the team have identified black hole jets as a possible driver of galaxy formation, which may also represent the long-sought missing link to understanding why the mass of black holes is larger in galaxies that contain more stars [3]. "A natural extension of our work is to search for similar objects in other systems," says Jahnke. Future instruments, such as the Atacama Large Millimeter/submillimeter Array, the European Extremely Large Telescope and the NASA/ESA/CSA James Webb Space Telescope will be able to search for such objects at even larger distances from us, probing the connection between black holes and the formation of galaxies in the more distant Universe. Notes [1] Supermassive black holes are found in the cores of most large galaxies; unlike the inactive and starving one sitting at the centre of the Milky Way, a fraction of them are said to be active, as they eat up enormous amounts of material. These frantic actions produce a copious release of energy

  13. Wall crossing from Boltzmann black hole halos

    NASA Astrophysics Data System (ADS)

    Manschot, Jan; Pioline, Boris; Sen, Ashoke

    2011-07-01

    A key question in the study of mathcal{N} = 2 supersymmetric string or field theories is to understand the decay of BPS bound states across walls of marginal stability in the space of parameters or vacua. By representing the potentially unstable bound states as multi-centered black hole solutions in mathcal{N} = 2 supergravity, we provide two fully general and explicit formulæ for the change in the (refined) index across the wall. The first, "Higgs branch" formula relies on Reineke's results for invariants of quivers without oriented loops, specialized to the Abelian case. The second, "Coulomb branch" formula results from evaluating the symplectic volume of the classical phase space of multi-centered solutions by localization. We provide extensive evidence that these new formulæ agree with each other and with the mathematical results of Kontsevich and Soibelman (KS) and Joyce and Song (JS). The main physical insight behind our results is that the Bose-Fermi statistics of individual black holes participating in the bound state can be traded for Maxwell-Boltzmann statistics, provided the (integer) index Ω( γ) of the internal degrees of freedom carried by each black hole is replaced by an effective (rational) index bar{Ω }left( γ right) = sumnolimits_{left. m right|γ } {{{{Ω left( {{{γ } left/ {m} right.}} right)}} left/ {{{m^2}}} right.}} similar map also exists for the refined index. This observation provides a physical rationale for the appearance of the rational Donaldson-Thomas invariant bar{Ω }left( γ right) in the works of KS and JS.

  14. Cosmological expansion and local physics

    SciTech Connect

    Faraoni, Valerio; Jacques, Audrey

    2007-09-15

    The interplay between cosmological expansion and local attraction in a gravitationally bound system is revisited in various regimes. First, weakly gravitating Newtonian systems are considered, followed by various exact solutions describing a relativistic central object embedded in a Friedmann universe. It is shown that the 'all or nothing' behavior recently discovered (i.e., weakly coupled systems are comoving while strongly coupled ones resist the cosmic expansion) is limited to the de Sitter background. New exact solutions are presented which describe black holes perfectly comoving with a generic Friedmann universe. The possibility of violating cosmic censorship for a black hole approaching the big rip is also discussed.

  15. Photodetachment of gaseous multiply charged anions, copper phthalocyanine tetrasulfonate tetraanion: Tuning molecular electronic energy levels by charging and negative electron binding

    SciTech Connect

    Wang, X.B.; Ferris, K.; Wang, L.S.

    2000-01-13

    The authors report photodetachment photoelectron spectroscopy (PES) of gaseous copper phthalocyanine (CuPc) tetrasulfonate quadruply charged anions, [CuPc(SO{sub 3}){sub 4}]{sup 4{minus}}, and its monoprotonated and -sodiumated triply charged anions, [CuPc(SO{sub 3}){sub 4}H]{sup 3{minus}} and [CuPc(SO{sub 3}){sub 4}Na]{sup 3{minus}}. The [CuPc(SO{sub 3}){sub 4}]{sup 4{minus}} tetraanion was found to possess a negative electron binding energy of {minus}0.9 eV, whereas the trianions have binding energies of 1.0 and 1.2 eV for the sodiumated and protonated species, respectively. The PES spectral features of the three multiply charged anions were observed to be similar to that of the parent CuPc neutral molecule, except that the anions have lower binding energies due to the presence of the negative charges ({minus}SO{sub 3}{sup {minus}}). The data thus suggested a stepwise tuning of the molecular electronic energy levels of the CuPc molecule through charging, wherein the molecular orbital energies of the parent molecule were systematically pushed up by the negative charges. The authors further carried out semiempirical calculations, which provided insight into the nature of the localized charges on the peripheral {minus}SO{sub 3}{sup {minus}} groups and the intramolecular electrostatic interactions in the multiply charged anions and confirmed the interpretation of the stepwise tuning of molecular energy levels by charging. Photon energy-dependent studies revealed the effects of the repulsive Coulomb barriers on the photodetachment PES spectra of the multiply charged anions. The barrier heights were estimated to be about 3.5 and 2.5 eV for the tetra- and trianions, respectively. The authors also observed excited states for the multiply charged anions and resonant tunneling through the repulsive Coulomb barriers via the excited states.

  16. The self-consistent calculation of pseudo-molecule energy levels, construction of energy level correlation diagrams and an automated computation system for SCF-X(Alpha)-SW calculations

    NASA Technical Reports Server (NTRS)

    Schlosser, H.

    1981-01-01

    The self consistent calculation of the electronic energy levels of noble gas pseudomolecules formed when a metal surface is bombarded by noble gas ions is discussed along with the construction of energy level correlation diagrams as a function of interatomic spacing. The self consistent field x alpha scattered wave (SCF-Xalpha-SW) method is utilized. Preliminary results on the Ne-Mg system are given. An interactive x alpha programming system, implemented on the LeRC IBM 370 computer, is described in detail. This automated system makes use of special PROCDEFS (procedure definitions) to minimize the data to be entered manually at a remote terminal. Listings of the special PROCDEFS and of typical input data are given.

  17. Wormholes as black hole foils

    NASA Astrophysics Data System (ADS)

    Damour, Thibault; Solodukhin, Sergey N.

    2007-07-01

    We study to what extent wormholes can mimic the observational features of black holes. It is surprisingly found that many features that could be thought of as “characteristic” of a black hole (endowed with an event horizon) can be closely mimicked by a globally static wormhole, having no event horizon. This is the case for the apparently irreversible accretion of matter down a hole, no-hair properties, quasi-normal-mode ringing, and even the dissipative properties of black hole horizons, such as a finite surface resistivity equal to 377 Ohms. The only way to distinguish the two geometries on an observationally reasonable time scale would be through the detection of Hawking’s radiation, which is, however, too weak to be of practical relevance for astrophysical black holes. We point out the existence of an interesting spectrum of quantum microstates trapped in the throat of a wormhole which could be relevant for storing the information lost during a gravitational collapse.

  18. A unitary model of the black hole evaporation

    NASA Astrophysics Data System (ADS)

    Feng, Yu-Lei; Chen, Yi-Xin

    2014-12-01

    A unitary effective field model of the black hole evaporation is proposed to satisfy almost the four postulates of the black hole complementarity (BHC). In this model, we enlarge a black hole-scalar field system by adding an extra radiation detector that couples with the scalar field. After performing a partial trace over the scalar field space, we obtain an effective entanglement between the black hole and the detector (or radiation in it). As the whole system evolves, the S-matrix formula can be constructed formally step by step. Without local quantum measurements, the paradoxes of the information loss and AMPS's firewall can be resolved. However, the information can be lost due to quantum decoherence, as long as some local measurement has been performed on the detector to acquire the information of the radiation in it. But unlike Hawking's completely thermal spectrum, some residual correlations can be found in the radiations. All these considerations can be simplified in a qubit model that provides a modified quantum teleportation to transfer the information via an EPR pairs.

  19. Possible astrophysical observables of quantum gravity effects near black holes

    NASA Astrophysics Data System (ADS)

    Pen, Ue-Li; Broderick, Avery E.

    2014-12-01

    Recent implications of results from quantum information theory applied to black holes have led to the confusing conclusions that require either abandoning the equivalence principle (e.g. the firewall picture), or locality, or even more unpalatable options. The recent discovery of a pulsar orbiting a black hole opens up new possibilities for tests of theories of gravity. We examine possible observational effects of semiclassical quantum gravity in the vicinity of black holes, as probed by pulsars and event horizon telescope imaging of flares. In some cases, pulsar radiation may be observable at wavelengths only two orders of magnitude shorter than the Hawking radiation, so precision interferometry of lensed pulsar images may shed light on the quantum gravitational processes and interaction of Hawking radiation with the space-time near the black hole. This paper discusses the impact on the pulsar radiation interference pattern, which is observable through the modulation index in the foreseeable future, and discusses a possible classical limit of non-locality.

  20. Thermodynamics of charged black holes with a nonlinear electrodynamics source

    SciTech Connect

    Gonzalez, Hernan A.; Hassaiene, Mokhtar; Martinez, Cristian

    2009-11-15

    We study the thermodynamical properties of electrically charged black hole solutions of a nonlinear electrodynamics theory defined by a power p of the Maxwell invariant, which is coupled to Einstein gravity in four and higher spacetime dimensions. Depending on the range of the parameter p, these solutions present different asymptotic behaviors. We compute the Euclidean action with the appropriate boundary term in the grand canonical ensemble. The thermodynamical quantities are identified and, in particular, the mass and the charge are shown to be finite for all classes of solutions. Interestingly, a generalized Smarr formula is derived and it is shown that this latter encodes perfectly the different asymptotic behaviors of the black hole solutions. The local stability is analyzed by computing the heat capacity and the electrical permittivity and we find that a set of small black holes is locally stable. In contrast to the standard Reissner-Nordstroem solution, there is a first-order phase transition between a class of these nonlinear charged black holes and the Minkowski spacetime.

  1. Scintillation Hole Observed by FORMOSAT-3/COSMIC

    NASA Astrophysics Data System (ADS)

    Chen, Shih Ping; Yenq Liu, Jann; Krishnanunni Rajesh, Panthalingal

    2013-04-01

    Ionospheric scintillations can significantly disturb satellite positioning, navigation, and communication. FORMOSAT-3/COSMIC provides the first 3-D global observation by solo instrument (radio occultation experiment, GOX). The GPS L-band amplitude fluctuation from 50Hz signal is received and recorded by F3/C GOX to calculate S4-index from 50-800km altitude. The global F3/C S4 index are subdivided and examined in various latitudes, longitudes, altitudes, and seasons during 2007-2012. The F-region scintillations in the equatorial and low-latitude ionosphere start around post-sunset period and often persist till post-midnight hours (0300 MLT, magnetic local time) during the March and September equinox as well as December Solstice seasons. The E-region scintillations reveal a clear solar zenith effect and yield pronounced intensities in mid-latitudes during the Summer Solstice seasons, which are well correlated with occurrences of the sporadic E-layer. It is interesting to find there is no scintillation, which is termed "scintillation hole", in the E region ranging from 80 to 130km altitude over the South Africa region, and become the most pronounced in November-January (December Solstice seasons or summer months). Other space-borne and ground based observations are use to confirm the existence of the scintillation hole.

  2. The lamppost model of accreting black holes

    NASA Astrophysics Data System (ADS)

    Zdziarski, A.

    2016-06-01

    Niedzwiecki, Zdziarski & Szanecki (2016, ApJL, submitted) have studied the lamppost model, in which the X-ray source in accreting black-hole systems is located on the rotation axis close to the horizon. We point out a number of inconsistencies in the widely used lamppost model relxilllp. They appear to invalidate those model fitting results for which the source distances from the horizon are within several gravitational radii. Furthermore, we note that if those results were correct, most of the photons produced in the lamppost would be trapped by the black hole, and the source luminosity as measured at infinity would be much larger than that observed. This appears to be in conflict with the observed smooth state transitions between the hard and soft states of X-ray binaries. The required increase of the accretion rate and the associated efficiency reduction present also a problem for AGNs. Then, those models imply the luminosity measured in the local frame much higher than the dissipated power due to time dilation and redshift, and the electron temperature significantly higher than that observed. We show that these conditions imply that the fitted sources would be out of the pair equilibrium.

  3. Magnetohydrodynamical Analogue of a Black Hole

    NASA Astrophysics Data System (ADS)

    Zamorano, Nelson; Asenjo, Felipe

    2014-03-01

    We study the conditions that a plasma fluid and its container should meet to generate a magneto-acoustic horizon. This effect becomes an alternative to the analogue black hole found in a transonic fluid flow setting. In this context we use the magnetohydrodynamic formalism (MHD) to analyze the evolution of an irrotational plasma fluid interacting with an external constant magnetic field. Under certain plausible approximations, the dynamic of the field perturbations is described by a scalar field potential that follows a second order differential equation. As we prove here, this equation corresponds to the wave equation associated to a scalar field in a curved space-time. This horizon emerges when the local speed of the medium grows larger than the sound velocity. The magnetic field generates an effective pressure which contributes to the magneto-acoustic speed. We compare these results with the known physics of analogue black holes. We will also refer to our ongoing experiment that, in its first stage, attempts to reproduce the wave horizons found in an open channel with an obstacle: PRL 106, 021302 (2011).

  4. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  5. Low-mass black holes as the remnants of primordial black hole formation

    NASA Astrophysics Data System (ADS)

    Greene, Jenny E.

    2012-12-01

    Bridging the gap between the approximately ten solar mass `stellar mass' black holes and the `supermassive' black holes of millions to billions of solar masses are the elusive `intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ~104-105Msolar black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

  6. Calabi-Yau black holes

    NASA Astrophysics Data System (ADS)

    Shmakova, Marina

    1997-07-01

    We find the entropy of N=2 extreme black holes associated with general Calabi-Yau moduli space and the prepotential F=dABC(XAXBXC/X0). We show that for arbitrary dABC and black hole charges p and q the entropy-area formula depends on combinations of these charges and parameters dABC. These combinations are the solutions of a simple system of algebraic equations. We give a few examples of particular Calabi-Yau moduli spaces for which this system has an explicit solution. For the special case when one of the black hole charges is equal to zero (p0=0) the solution always exists.

  7. Quantum Criticality and Black Holes

    SciTech Connect

    Sachdev, Subir

    2007-08-22

    I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.

  8. Liouvillian perturbations of black holes

    NASA Astrophysics Data System (ADS)

    Couch, W. E.; Holder, C. L.

    2007-10-01

    We apply the well-known Kovacic algorithm to find closed form, i.e., Liouvillian solutions, to the differential equations governing perturbations of black holes. Our analysis includes the full gravitational perturbations of Schwarzschild and Kerr, the full gravitational and electromagnetic perturbations of Reissner-Nordstrom, and specialized perturbations of the Kerr-Newman geometry. We also include the extreme geometries. We find all frequencies ω, in terms of black hole parameters and an integer n, which allow Liouvillian perturbations. We display many classes of black hole parameter values and their corresponding Liouvillian perturbations, including new closed-form perturbations of Kerr and Reissner-Nordstrom. We also prove that the only type 1 Liouvillian perturbations of Schwarzschild are the known algebraically special ones and that type 2 Liouvillian solutions do not exist for extreme geometries. In cases where we do not prove the existence or nonexistence of Liouvillian perturbations we obtain sequences of Diophantine equations on which decidability rests.

  9. Tomograms of spinning black holes

    SciTech Connect

    Krishnan, Chethan

    2009-12-15

    The classical internal structure of spinning black holes is vastly different from that of static black holes. We consider spinning Banados-Teitelboim-Zanelli black holes, and probe their interior from the gauge theory. Utilizing the simplicity of the geometry and reverse engineering from the geodesics, we propose a thermal correlator construction which can be interpreted as arising from two entangled conformal field theories. By analytic continuation of these correlators, we can probe the Cauchy horizon. Correlators that capture the Cauchy horizon in our work have a structure closely related to those that capture the singularity in a nonrotating Banados-Teitelboim-Zanelli. As expected, the regions beyond the Cauchy horizon are not probed in this picture, protecting cosmic censorship.

  10. Quantum Criticality and Black Holes

    ScienceCinema

    Sachdev, Subir [Harvard University, Cambridge, Massachusetts, United States

    2016-07-12

    I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.

  11. Nonrotating and slowly rotating holes

    NASA Astrophysics Data System (ADS)

    MacDonald, Douglas A.; Price, Richard H.; Thorne, Kip S.; Suen, Wai-Mo

    The 3+1 formalism is applied to model Schwarzschild spacetime around a black hole. Particular note is taken of the 3+1 split of the laws of electrodynamics, and of the tendency of the approach to freeze motion at the event horizon. The null horizon is replaced with a timelike physical membrane which exhibits mechanical, thermodynamic and electrical properties, and which 'stretches' the horizon. The usefulness of the stretching approach is illustrated by considering a black hole penetrated by vibrating magnetic field lines anchored in a perfectly conducting surrounding sphere. The necessity of modeling the field structure near the actual horizon is avoided by having the field end at the membrane. The surface charge, current, resistivity and ohmic heating of the stretched horizon are also considered, and the Lorentz force imparted to the stretched horizon surface by the field lines is investigated by examining a nearly Schwarzschild hole behaving as the rotor of an electric motor.

  12. Neutron stars and black holes

    NASA Technical Reports Server (NTRS)

    Lamb, F. K.

    1991-01-01

    The radiation of neutron stars is powered by accretion, rotation, or internal heat; accreting black holes are thought to be the central engines of AGNs and of a handful of binary X-ray sources in the Galaxy. The evolution of a neutron star depends on the coupling between the rotating neutron and proton fluids in the interior, and between these fluids and the crust; it also depends on the magnetic and thermal properties of the star. Significant progress has been made in recent years in the understanding of radial and disk accretion by black holes. Radiation from pair plasmas may make an important contribution to the X- and gamma-ray spectra of AGNs and black holes in binary systems.

  13. Black holes with vector hair

    NASA Astrophysics Data System (ADS)

    Fan, Zhong-Ying

    2016-09-01

    In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.

  14. Astrophysical Black Holes: Evidence of a Horizon?

    NASA Astrophysics Data System (ADS)

    Colpi, Monica

    In this Lecture Note we first follow a short account of the history of the black hole hypothesis. We then review on the current status of the search for astrophysical black holes with particular attention to the black holes of stellar origin. Later, we highlight a series of observations that reveal the albeit indirect presence of supermassive black holes in galactic nuclei, with mention to forthcoming experiments aimed at testing directly the black hole hypothesis. We further focus on evidences of a black hole event horizon in cosmic sources.

  15. Calculation of Electrochemical Energy Levels in Water Using the Random Phase Approximation and a Double Hybrid Functional.

    PubMed

    Cheng, Jun; VandeVondele, Joost

    2016-02-26

    Understanding charge transfer at electrochemical interfaces requires consistent treatment of electronic energy levels in solids and in water at the same level of the electronic structure theory. Using density-functional-theory-based molecular dynamics and thermodynamic integration, the free energy levels of six redox couples in water are calculated at the level of the random phase approximation and a double hybrid density functional. The redox levels, together with the water band positions, are aligned against a computational standard hydrogen electrode, allowing for critical analysis of errors compared to the experiment. It is encouraging that both methods offer a good description of the electronic structures of the solutes and water, showing promise for a full treatment of electrochemical interfaces.

  16. Energy levels of GaAs/AlxGa1-xAs/AlAs spherical quantum dot with an impurity

    NASA Astrophysics Data System (ADS)

    Boz, Figen Karaca; Nisanci, Beyza; Aktas, Saban; Okan, S. Erol

    2016-11-01

    We have calculated the energy levels and the radial probability distributions of an electron with an impurity in a spherical quantum dot which is layered as GaAs/AlxGa1-xAs/AlAs. The numerical method used is the fourth-order Runge-Kutta method in the framework of the effective mass approximation. The variation of the energy levels have been calculated as functions of the radius of the GaAs sphere and the thickness of AlxGa1-xAs spherical layer considering effective mass and dielectric constant mismatches. The results have presented the importance of the geometry on the electronic properties of the spherical GaAs/AlxGa1-xAs/AlAs quantum dot.

  17. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  18. Building Black Holes: Supercomputer Cinema

    NASA Astrophysics Data System (ADS)

    Shapiro, Stuart L.; Teukolsky, Saul A.

    1988-07-01

    A new computer code can solve Einstein's equations of general relativity for the dynamical evolution of a relativistic star cluster. The cluster may contain a large number of stars that move in a strong gravitational field at speeds approaching the speed of light. Unstable star clusters undergo catastrophic collapse to black holes. The collapse of an unstable cluster to a supermassive black hole at the center of a galaxy may explain the origin of quasars and active galactic nuclei. By means of a supercomputer simulation and color graphics, the whole process can be viewed in real time on a movie screen.

  19. Total optical transmission through a small hole in a metal waveguide screen.

    PubMed

    Pang, Y; Hone, A N; So, P P M; Gordon, R

    2009-03-16

    We present the theory of total optical transmission through a small hole in metal waveguide screen. Unlike past works on extraordinary optical transmission using arrays, there is only a single hole; yet, the theory predicts total transmission for a perfect electric conductor (not normalized to the hole size) 100% transmission, regardless of how small the hole. This is very surprising considering the usual application of Bethe's theory to waveguide apertures. Comprehensive numerical simulations agree well with the theory and their modal-analysis supports the proposed evanescent-mode mechanism for total transmission. These simulations are extended to show the influence of realistic material response (including loss) at microwave and visible-infrared frequencies. Due to the strong resonant field localization and transmission from only a thin metal screen with a single hole, many promising applications arise for this phenomenon including filtering, sensing, plasma generation, nonlinear optics, spectroscopy, heating, optical trapping, near-field microscopy and cavity quantum electrodynamics.

  20. Seeds to monsters: tracing the growth of black holes in the universe

    NASA Astrophysics Data System (ADS)

    Natarajan, Priyamvada

    2014-05-01

    An overview of our current knowledge of black seed formation models following their growth history over cosmic time is presented. Both light seed formation channels remnants of the first stars and the more massive direct collapse seed formation scenarios are outlined. In particular, the focus is on the implications of these various scenarios and what these initial conditions imply for the highest redshift black holes, the local black hole population, the highest mass black holes at each epoch and the low mass end of the black hole mass function all of which are currently observed. The goal is to present a broad and comprehensive picture of the current status; the open questions and challenges faced by black hole growth models in matching current observational data and the prospects for future observations that will help discriminate between competing models.

  1. Electric Properties of Obsidian: Evidence for Positive Hole Charge Carriers

    NASA Astrophysics Data System (ADS)

    Nordvik, R.; Freund, F. T.

    2012-12-01

    The blackness of obsidian is due to the presence of oxygen anions in the valence state 1-, creating broad energy levels at the upper edge of the valence band, which absorb visible light over a wide spectral range. These energy states are associated with defect electrons in the oxygen anion sublattice, well-known from "smoky quartz", where Al substituting for Si captures a defect electron in the oxygen anion sublattice for charge compensation [1]. Such defect electrons, also known as positive holes, are responsible for the increase in electrical conductivity in igneous rocks when uniaxial stresses are applied, causing the break-up of pre-existing peroxy defects, Si-OO-Si [2]. Peroxy defects in obsidian cannot be so easily activated by mechanical stress because the glassy matrix will break before sufficiently high stress levels can be reached. If peroxy defects do exist, however, they can be studied by activating them thermally [3]. We describe experiments with rectangular slabs of obsidian with Au electrodes at both ends. Upon heating one end, we observe (i) a thermopotential and (ii) a thermocurrent developing at distinct temperatures around 250°C and 450°C, marking the 2-step break-up of peroxy bonds. [1] Schnadt, R., and Schneider, J.: The electronic structure of the trapped-hole center in smoky quartz, Zeitschrift Physik B Condensed Matter 11, 19-42, 1970. [2] Freund, F. T., Takeuchi, A., and Lau, B. W.: Electric currents streaming out of stressed igneous rocks - A step towards understanding pre-earthquake low frequency EM emissions, Physics and Chemistry of the Earth, 31, 389-396, 2006. [3] Freund, F., and Masuda, M. M.: Highly mobile oxygen hole-type charge carriers in fused silica, Journal Material Research, 8, 1619-1622, 1991.

  2. Distorted five-dimensional electrically charged black holes

    NASA Astrophysics Data System (ADS)

    Abdolrahimi, Shohreh; Shoom, Andrey A.

    2014-01-01

    In this paper, we study distorted, five-dimensional, electrically charged (nonextremal) black holes on the example of a static and "axisymmetric" black hole distorted by external, electrically neutral matter. Such a black hole is represented by the solution derived here of the Einstein-Maxwell equations which admits an R1×U(1)×U(1) isometry group. The external matter, which is "located" at the asymptotic infinity, is not included in the solution. The space-time singularities are located behind the black hole's inner (Cauchy) horizon, provided that the sources of the distortion satisfy the strong energy condition. The inner (Cauchy) horizon remains regular if the distortion fields are finite and smooth at the outer horizon. The solution has some remarkable properties. There exists a certain duality transformation between the inner and the outer horizon surfaces which links surface gravity, electrostatic potential, and space-time curvature invariants calculated at the black hole horizons. The product of the inner and outer horizon areas depends only on the black hole's electric charge, and the geometric mean of the areas is the upper (lower) limit for the inner (outer) horizon area. The electromagnetic field invariant calculated at the horizons is proportional to the squared surface gravity of the horizons. The horizon areas, electrostatic potential, and surface gravity satisfy the Smarr formula. We formulated the zeroth and the first laws of mechanics and thermodynamics of the distorted black hole and found a correspondence between the global and local forms of the first law. To illustrate the effect of distortion, we consider the dipole-monopole and quadrupole-quadrupole distortion fields. The relative change in the Kretschmann scalar due to the distortion is greater at the outer horizon than at the inner one. By calculating the maximal proper time of free fall from the outer to the inner horizons, we show that the distortion can noticeably change the black hole

  3. Black holes and the butterfly effect

    NASA Astrophysics Data System (ADS)

    Shenker, Stephen H.; Stanford, Douglas

    2014-03-01

    We use holography to study sensitive dependence on initial conditions in strongly coupled field theories. Specifically, we mildly perturb a thermofield double state by adding a small number of quanta on one side. If these quanta are released a scrambling time in the past, they destroy the local two-sided correlations present in the unperturbed state. The corresponding bulk geometry is a two-sided AdS black hole, and the key effect is the blueshift of the early infalling quanta relative to the t = 0 slice, creating a shock wave. We comment on string- and Planck-scale corrections to this setup, and discuss points that may be relevant to the firewall controversy.

  4. Ab initio potential energy surface and vibration-rotation energy levels of silicon dicarbide, SiC2.

    PubMed

    Koput, Jacek

    2016-10-01

    The accurate ground-state potential energy surface of silicon dicarbide, SiC2 , has been determined from ab initio calculations using the coupled-cluster approach. Results obtained with the conventional and explicitly correlated coupled-cluster methods were compared. The core-electron correlation, higher-order valence-electron correlation, and scalar relativistic effects were taken into account. The potential energy barrier to the linear SiCC configuration was predicted to be 1782 cm(-1) . The vibration-rotation energy levels of the SiC2 , (29) SiC2 , (30) SiC2 , and SiC(13) C isotopologues were calculated using a variational method. The experimental vibration-rotation energy levels of the main isotopologue were reproduced to high accuracy. In particular, the experimental energy levels of the highly anharmonic vibrational ν3 mode of SiC2 were reproduced to within 6.7 cm(-1) , up to as high as the v3  = 16 state.

  5. Ab initio potential energy surface and vibration-rotation energy levels of silicon dicarbide, SiC2.

    PubMed

    Koput, Jacek

    2016-10-01

    The accurate ground-state potential energy surface of silicon dicarbide, SiC2 , has been determined from ab initio calculations using the coupled-cluster approach. Results obtained with the conventional and explicitly correlated coupled-cluster methods were compared. The core-electron correlation, higher-order valence-electron correlation, and scalar relativistic effects were taken into account. The potential energy barrier to the linear SiCC configuration was predicted to be 1782 cm(-1) . The vibration-rotation energy levels of the SiC2 , (29) SiC2 , (30) SiC2 , and SiC(13) C isotopologues were calculated using a variational method. The experimental vibration-rotation energy levels of the main isotopologue were reproduced to high accuracy. In particular, the experimental energy levels of the highly anharmonic vibrational ν3 mode of SiC2 were reproduced to within 6.7 cm(-1) , up to as high as the v3  = 16 state. PMID:27481562

  6. Probing the energy levels of perovskite solar cells via Kelvin probe and UV ambient pressure photoemission spectroscopy.

    PubMed

    Harwell, J R; Baikie, T K; Baikie, I D; Payne, J L; Ni, C; Irvine, J T S; Turnbull, G A; Samuel, I D W

    2016-07-20

    The field of organo-lead halide perovskite solar cells has been rapidly growing since their discovery in 2009. State of the art devices are now achieving efficiencies comparable to much older technologies like silicon, while utilising simple manufacturing processes and starting materials. A key parameter to consider when optimising solar cell devices or when designing new materials is the position and effects of the energy levels in the materials. We present here a comprehensive study of the energy levels present in a common structure of perovskite solar cell using an advanced macroscopic Kelvin probe and UV air photoemission setup. By constructing a detailed map of the energy levels in the system we are able to predict the importance of each layer to the open circuit voltage of the solar cell, which we then back up through measurements of the surface photovoltage of the cell under white illumination. Our results demonstrate the effectiveness of air photoemission and Kelvin probe contact potential difference measurements as a method of identifying the factors contributing to the open circuit voltage in a solar cell, as well as being an excellent way of probing the physics of new materials.

  7. Energy levels, oscillator strengths, and radiative rates for Si-like Zn XVII, Ga XVIII, Ge XIX, and As XX

    SciTech Connect

    Abou El-Maaref, A.; Allam, S.H.; El-Sherbini, Th.M.

    2014-01-15

    The energy levels, oscillator strengths, line strengths, and transition probabilities for transitions among the terms belonging to the 3s{sup 2}3p{sup 2}, 3s3p{sup 3}, 3s{sup 2}3p3d, 3s{sup 2}3p4s, 3s{sup 2}3p4p and 3s{sup 2}3p4d configurations of silicon-like ions (Zn XVII, Ga XVIII, Ge XIX, and As XX) have been calculated using the configuration-interaction code CIV3. The calculations have been carried out in the intermediate coupling scheme using the Breit–Pauli Hamiltonian. The present calculations have been compared with the available experimental data and other theoretical calculations. Most of our calculations of energy levels and oscillator strengths (in length form) show good agreement with both experimental and theoretical data. Lifetimes of the excited levels have also been calculated. -- Highlights: •We have calculated the fine-structure energy levels of Si-like Zn, Ga, Ge and As. •The calculations are performed using the configuration interaction method (CIV3). •We have calculated the oscillator strengths, line strengths and transition rates. •The wavelengths of the transitions are listed in this article. •We also have made comparisons between our data and other calculations.

  8. Position-dependent energy-level shifts of an accelerated atom in the presence of a boundary

    SciTech Connect

    Zhu Zhiying; Yu Hongwei

    2010-10-15

    We consider a uniformly accelerated atom interacting with a vacuum electromagnetic field in the presence of an infinite conducting plane boundary and calculate separately the contributions of vacuum fluctuations and radiation reaction to the atomic energy-level shift. We analyze in detail the behavior of the total energy shift in three different regimes of the distance in both the low-acceleration and high-acceleration limits. Our results show that, in general, an accelerated atom does not behave as if immersed in a thermal bath at the Unruh temperature in terms of the atomic energy-level shifts, and the effect of the acceleration on the atomic energy-level shifts may in principle become appreciable in certain circumstances, although it may not be realistic for actual experimental measurements. We also examine the effects of the acceleration on the level shifts when the acceleration is of the order of the transition frequency of the atom and we find some features which differ from what was obtained in the existing literature.

  9. Probing the energy levels of perovskite solar cells via Kelvin probe and UV ambient pressure photoemission spectroscopy.

    PubMed

    Harwell, J R; Baikie, T K; Baikie, I D; Payne, J L; Ni, C; Irvine, J T S; Turnbull, G A; Samuel, I D W

    2016-07-20

    The field of organo-lead halide perovskite solar cells has been rapidly growing since their discovery in 2009. State of the art devices are now achieving efficiencies comparable to much older technologies like silicon, while utilising simple manufacturing processes and starting materials. A key parameter to consider when optimising solar cell devices or when designing new materials is the position and effects of the energy levels in the materials. We present here a comprehensive study of the energy levels present in a common structure of perovskite solar cell using an advanced macroscopic Kelvin probe and UV air photoemission setup. By constructing a detailed map of the energy levels in the system we are able to predict the importance of each layer to the open circuit voltage of the solar cell, which we then back up through measurements of the surface photovoltage of the cell under white illumination. Our results demonstrate the effectiveness of air photoemission and Kelvin probe contact potential difference measurements as a method of identifying the factors contributing to the open circuit voltage in a solar cell, as well as being an excellent way of probing the physics of new materials. PMID:27384817

  10. Improved black hole fireworks: Asymmetric black-hole-to-white-hole tunneling scenario

    NASA Astrophysics Data System (ADS)

    De Lorenzo, Tommaso; Perez, Alejandro

    2016-06-01

    A new scenario for gravitational collapse has been recently proposed by Haggard and Rovelli. Presenting the model under the name of black hole fireworks, they claim that the accumulation of quantum gravitational effects outside the horizon can cause the tunneling of geometry from a black hole to a white hole, allowing a bounce of the collapsing star which can eventually go back to infinity. In this paper, we discuss the instabilities of this model and propose a simple minimal modification which eliminates them, as well as other related instabilities discussed in the literature. The new scenario is a time-asymmetric version of the original model with a time scale for the final explosion that is shorter than m log m in Planck units. Our analysis highlights the importance of irreversibility in gravitational collapse which, in turn, uncovers important issues that cannot be addressed in detail without a full quantum gravity treatment.

  11. A toy model of black hole complementarity

    NASA Astrophysics Data System (ADS)

    Banerjee, Souvik; Bryan, Jan-Willem; Papadodimas, Kyriakos; Raju, Suvrat

    2016-05-01

    We consider the algebra of simple operators defined in a time band in a CFT with a holographic dual. When the band is smaller than the light crossing time of AdS, an entire causal diamond in the center of AdS is separated from the band by a horizon. We show that this algebra obeys a version of the Reeh-Schlieder theorem: the action of the algebra on the CFT vacuum can approximate any low energy state in the CFT arbitrarily well, but no operator within the algebra can exactly annihilate the vacuum. We show how to relate local excitations in the complement of the central diamond to simple operators in the band. Local excitations within the diamond are invisible to the algebra of simple operators in the band by causality, but can be related to complicated operators called "precursors". We use the Reeh-Schlieder theorem to write down a simple and explicit formula for these precursors on the boundary. We comment on the implications of our results for black hole complementarity and the emergence of bulk locality from the boundary.

  12. Considerations for fine hole patterning for the 7nm node

    NASA Astrophysics Data System (ADS)

    Yaegashi, Hidetami; Oyama, Kenichi; Hara, Arisa; Natori, Sakurako; Yamauchi, Shohei; Yamato, Masatoshi; Koike, Kyohei

    2016-03-01

    One of the practical candidates to produce 7nm node logic devices is to use the multiple patterning with 193-immersion exposure. For the multiple patterning, it is important to evaluate the relation between the number of mask layer and the minimum pitch systematically to judge the device manufacturability. Although the number of the time of patterning, namely LE(Litho-Etch) ^ x-time, and overlay steps have to be reduced, there are some challenges in miniaturization of hole size below 20nm. Various process fluctuations on contact hole have a direct impact on device performance. According to the technical trend, 12nm diameter hole on 30nm-pitch hole will be needed on 7nm node. Extreme ultraviolet lithography (EUV) and Directed self-assembly (DSA) are attracting considerable attention to obtain small feature size pattern, however, 193-immersion still has the potential to extend optical lithography cost-effectively for sub-7nm node. The objective of this work is to study the process variation challenges and resolution in post-processing for the CD-bias control to meet sub-20nm diameter contact hole. Another pattern modulation is also demonstrated during post-processing step for hole shrink. With the realization that pattern fidelity and pattern placement management will limit scaling long before devices and interconnects fail to perform intrinsically, the talk will also outline how circle edge roughness (CER) and Local-CD uniformity can correct efficiency. On the other hand, 1D Gridded-Design-Rules layout (1D layout) has simple rectangular shapes. Also, we have demonstrated CD-bias modification on short trench pattern to cut grating line for its fabrication.

  13. Ultrathin Cu2O as an efficient inorganic hole transporting material for perovskite solar cells.

    PubMed

    Yu, Weili; Li, Feng; Wang, Hong; Alarousu, Erkki; Chen, Yin; Lin, Bin; Wang, Lingfei; Hedhili, Mohamed Nejib; Li, Yangyang; Wu, Kewei; Wang, Xianbin; Mohammed, Omar F; Wu, Tom

    2016-03-21

    We demonstrate that ultrathin P-type Cu2O thin films fabricated by a facile thermal oxidation method can serve as a promising hole-transporting material in perovskite solar cells. Following a two-step method, inorganic-organic hybrid perovskite solar cells were fabricated and a power conversion efficiency of 11.0% was achieved. We found that the thickness and properties of Cu2O layers must be precisely tuned in order to achieve the optimal solar cell performance. The good performance of such perovskite solar cells can be attributed to the unique properties of ultrathin Cu2O, including high hole mobility, good energy level alignment with CH3NH3PbI3, and longer lifetime of photo-excited carriers. Combining the merits of low cost, facile synthesis, and high device performance, ultrathin Cu2O films fabricated via thermal oxidation hold promise for facilitating the developments of industrial-scale perovskite solar cells.

  14. Repairing Holes in Pressure Walls

    NASA Technical Reports Server (NTRS)

    Mori, Paul Bruce Y.; Capriloa, Laurie J.; Corocado, Alexander R.; Gibbins, Martin N.; Horne, Robert B.

    1987-01-01

    Patches and easy-to-use tools yield pressure-tight seal. Repairer lifts patch from repair kit with hook-and-pile-tipped tool and positions it over puncture hole. With tool, even gloved repairer easily manipulates patch without damaging it.

  15. Black Holes: A Selected Bibliography.

    ERIC Educational Resources Information Center

    Fraknoi, Andrew

    1991-01-01

    Offers a selected bibliography pertaining to black holes with the following categories: introductory books; introductory articles; somewhat more advanced articles; readings about Einstein's general theory of relativity; books on the death of stars; articles on the death of stars; specific articles about Supernova 1987A; relevant science fiction…

  16. From Pinholes to Black Holes

    SciTech Connect

    Fenimore, Edward E.

    2014-10-06

    Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.

  17. Gravitational Collapse and Black Holes

    ERIC Educational Resources Information Center

    Ryder, Lewis

    1973-01-01

    The newest and most exotic manner in which stars die is investigated. A brief outline is presented, along with a discussion of the role supernova play, followed by a description of how the black holes originate, exist, and how they might be detected. (DF)

  18. 'Black holes': escaping the void.

    PubMed

    Waldron, Sharn

    2013-02-01

    The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche. PMID:23351000

  19. Side hole drilling in boreholes

    NASA Technical Reports Server (NTRS)

    Collins, Jr., Earl R. (Inventor)

    1980-01-01

    Apparatus for use in a borehole or other restricted space to bore a side hole into the strata surrounding the borehole, including a flexible shaft with a drill at its end, and two trains of sheathing members that can be progressively locked together into a rigid structure around the flexible shaft as it is directed sidewardly into the strata.

  20. Two Monster Black Holes at Work

    NASA Video Gallery

    Zoom into Markarian 739, a nearby galaxy hosting two monster black holes. Using NASA's Swift and Chandra, astronomers have shown that both black holes are producing energy as gas falls into them. T...