Sample records for ideal quantum gas

  1. Dissipation by ideal quantum gas

    E-print Network

    Janos Polonyi

    2015-02-09

    The effective Lagrangian of a test particle, interacting with an ideal gas, is calculated with in the Closed Time Path formalism in the one-loop and the leading order of the particle trajectory. The expansion in the time derivative is available for slow enough motion and it uncovers diffusive effective forces and decoherence for the coordinate and the momentum. A pure Newtonian friction force and an anisotrop coordinate decoherence are found for zero temperature ideal gas of fermions.

  2. Optimum criteria of an irreversible quantum Brayton refrigeration cycle with an ideal Bose gas

    Microsoft Academic Search

    Hao Wang; Sanqiu Liu; Jizhou He

    2008-01-01

    An irreversible cycle model of the quantum Brayton refrigeration cycle is established, in which finite-time processes and irreversibility in the two adiabatic processes are taken into account. On the basis of the thermodynamic properties of an ideal Bose gas, by using the optimal control-theory, the mathematical expressions for several important performance parameters, such as the coefficient of performance, power input

  3. Optimum criteria of an irreversible quantum Brayton refrigeration cycle with an ideal Bose gas

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Liu, Sanqiu; He, Jizhou

    2008-11-01

    An irreversible cycle model of the quantum Brayton refrigeration cycle is established, in which finite-time processes and irreversibility in the two adiabatic processes are taken into account. On the basis of the thermodynamic properties of an ideal Bose gas, by using the optimal control-theory, the mathematical expressions for several important performance parameters, such as the coefficient of performance, power input and cooling load, are derived and some important performance parameters, e.g., the temperatures of the working substance at several important state-points, are optimized. By means of numerical predictions, the optimal performance characteristic curves of a Bose-Brayton refrigeration cycle are obtained and analyzed. Furthermore, some optimal operating regions including those for the cooling load, coefficient of performance and the temperatures of the cyclic working substance at the two important state-points are determined and evaluated. Finally, several special cases are discussed in detail.

  4. Numerical solutions of ideal quantum gas dynamical flows governed by semiclassical ellipsoidal-statistical distribution.

    PubMed

    Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

    2014-01-01

    The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al. 2012 Proc. R. Soc. A 468, 1799-1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi-Dirac or Bose-Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas. PMID:24399919

  5. Re-Optimisation of Otto Power Cycles Working with Ideal Quantum Gases

    Microsoft Academic Search

    Altu Altu; Hasan Saygin

    2001-01-01

    To analyse the effect of quantum degeneracy of a working gas on the work optimisation of an ideal gas cycle, Otto power cycles working with ideal Bose and Fermi type quantum gases are considered. They are called Bose and Fermi Otto cycles respectively. Expressions for their net work outputs per cycle are derived by using the corrected ideal gas equation

  6. Box of Ideal Gas in Free Fall

    E-print Network

    Dawood Kothawala

    2013-02-27

    We study the \\textit{quantum} partition function of non-relativistic, ideal gas in a (non-cubical) box falling freely in arbitrary curved spacetime with centre 4-velocity u^a. When perturbed energy eigenvalues are properly taken into account, we find that corrections to various thermodynamic quantities include a very specific, sub-dominant term which is independent of \\textit{kinematic} details such as box dimensions and mass of particles. This term is characterized by the dimensionless quantity, \\Xi=R_00 \\Lambda^2, where R_00=R_ab u^a u^b and \\Lambda=\\beta \\hbar c, and, quite intriguingly, produces Euler relation of homogeneity two between entropy and energy -- a relation familiar from black hole thermodynamics.

  7. How Is the Ideal Gas Law Explanatory?

    ERIC Educational Resources Information Center

    Woody, Andrea I.

    2013-01-01

    Using the ideal gas law as a comparative example, this essay reviews contemporary research in philosophy of science concerning scientific explanation. It outlines the inferential, causal, unification, and erotetic conceptions of explanation and discusses an alternative project, the functional perspective. In each case, the aim is to highlight…

  8. Ideal gas matching for thermal Galilean holography

    E-print Network

    Jose L. F. Barbon; Carlos A. Fuertes

    2009-03-26

    We exhibit a nonrelativistic ideal gas with a Kaluza-Klein tower of species, featuring a singular behavior of thermodynamic functions at zero chemical potential. In this way, we provide a qualitative match to the thermodynamics of recently found black holes in backgrounds with asymptotic nonrelativistic conformal symmetry.

  9. WINDING-INVARIANT PRIME IDEALS IN QUANTUM 3 3 MATRICES

    E-print Network

    Lenagan, Tom

    WINDING-INVARIANT PRIME IDEALS IN QUANTUM 3 × 3 MATRICES K. R. Goodearl and T. H. Lenagan ¢¡¤£¦¥¨§¤©¨¥ A complete determination of the prime ideals invariant under winding auto- morphisms in the generic 3 × 3 heavily on certain tensor product decompositions for winding-invariant prime ideals, developed

  10. On Brownian motion in ideal gas and related principles

    E-print Network

    Yuriy E. Kuzovlev

    2008-06-25

    Brownian motion of particle interacting with atoms of ideal gas is discussed as a key problem of kinetics lying at the border between ``dead'' systems like the Lorentz gas or formal constructs of conceptual Boltzmannian kinetics and actual ``alive'' systems like mere gas possessing scaleless (1/f) fluctuations in their kinetic characteristics (e.g. in diffusuvity and mobility of the ``Brownian particle'').

  11. A LabVIEW Simulation of the Ideal Gas Transformations

    Microsoft Academic Search

    Marinela Ruset; George Bleaja

    In this paper, a software program concerning the ideal gas transformations is presented. The isotherm, the isocore and the isobar transformations are simulated using LabVIEW as a programming medium. The LabVIEW windows contain a vessel filled with a gas, a thermometer and a manometer indicated the temperature and the pressure respectively. The three parameters (V, T and P) are connected

  12. 1. Theory for Heat Capacity of Ideal Gas I ) KDB correlation equation (HC_CPGEQN)

    E-print Network

    Hong, Deog Ki

    1. Theory for Heat Capacity of Ideal Gas I ) KDB correlation equation (HC_CPGEQN) Polynomial equation is used for Heat capacity of ideal gas. = = 4 0 0 )( i i ip TATC (1) where, T is Kelvin and )( 0 TCp is kJ/kg-mol.K. 2. KDB Routines for Calculation of Ideal Gas Heat Capacity KDB Ideal gas heat

  13. A Demonstration of Ideal Gas Principles Using a Football

    Microsoft Academic Search

    William D. Bare; Lester Andrews; Timothy L. Pickering

    1999-01-01

    A class demonstration and cooperative learning activity in which the ideal gas law is applied to determine the volume of a football is described. The mass of an air-filled football is recorded at two or more pressures, and students are asked to use these data to solve problems involving the volume, pressure, and mass of the football and the molecular

  14. Cooling of an ideal gas by rapid expansion

    Microsoft Academic Search

    Jason Zimba

    2006-01-01

    We consider an ideal gas expansion in which the piston moves at speeds comparable to or greater than the average particle speed. We obtain a limiting expression for the small temperature change that results from this process. This example can help students enrich their understanding of the kinetic theory of gases and the meaning of temperature. Sample questions are included.

  15. Thermodynamics of Ideal Gas in Doubly Special Relativity

    E-print Network

    Nitin Chandra; Sandeep Chatterjee

    2012-02-22

    We study thermodynamics of an ideal gas in Doubly Special Relativity. New type of special functions (which we call Incomplete Modified Bessel functions) emerge. We obtain a series solution for the partition function and derive thermodynamic quantities. We observe that DSR thermodynamics is non-perturbative in the SR and massless limits. A stiffer equation of state is found.

  16. Ideal quantum gases in two dimensions

    Microsoft Academic Search

    S. Viefers; F. Ravndal; T. Haugset

    1995-01-01

    Thermodynamic properties of nonrelativistic bosons and fermions in two spatial dimensions and without interactions are derived. All the virial coefficients are the same except for the second, for which the signs are opposite. This results in the same specific heat for the two gases. Existing equations of state for the free anyon gas are also discussed and shown to break

  17. Viscosity of an ideal relativistic quantum fluid: A perturbative study

    E-print Network

    Giorgio Torrieri

    2012-02-14

    We show that a quantized ideal fluid will generally exhibit a small but non-zero viscosity due to the backreaction of quantum soundwaves on the background. We use an effective field theory expansion to estimate this viscosity to first order in perturbation theory. We discuss our results, and whether this estimate can be used to obtain a more model-independent estimate of the "quantum bound" on the viscosity of physical systems

  18. Influence of multi-irreversibilities on the performance of a Brayton refrigeration cycle working with an ideal Bose or Fermi gas

    Microsoft Academic Search

    Jingyi Liu; Bihong Lin; Weiqiang Hu; Jincan Chen

    2008-01-01

    An irreversible cycle model of the quantum Brayton refrigeration cycle using an ideal Bose or Fermi gas as the working substance is established. Based on the theory of statistical mechanics and thermodynamic properties of ideal quantum gases, expressions for several important performance parameters such as the cooling rate, coefficient of performance and power input, are derived. The influence of the

  19. How many is different? Answer from ideal Bose gas

    E-print Network

    Jeong-Hyuck Park

    2013-10-21

    How many $\\mathrm{H_{2}O}$ molecules are needed to form water? While the precise answer is not known, it is clear that the answer should be a finite number rather than infinity. We revisit with care the ideal Bose gas confined in a cubic box which is discussed in most statistical physics textbooks. We show that the isobar of the ideal gas zigzags on the temperature-volume plane featuring a `boiling-like' discrete phase transition, provided the number of particles is equal to or greater than a particular value: 7616. This demonstrates for the first time how a finite system can feature a mathematical singularity and realize the notion of `Emergence', without resorting to the thermodynamic limit.

  20. Efficient quantum processing of ideals in finite rings

    E-print Network

    Pawel M. Wocjan; Stephen P. Jordan; Hamed Ahmadi; Joseph P. Brennan

    2009-07-31

    Suppose we are given black-box access to a finite ring R, and a list of generators for an ideal I in R. We show how to find an additive basis representation for I in poly(log |R|) time. This generalizes a recent quantum algorithm of Arvind et al. which finds a basis representation for R itself. We then show that our algorithm is a useful primitive allowing quantum computers to rapidly solve a wide variety of problems regarding finite rings. In particular we show how to test whether two ideals are identical, find their intersection, find their quotient, prove whether a given ring element belongs to a given ideal, prove whether a given element is a unit, and if so find its inverse, find the additive and multiplicative identities, compute the order of an ideal, solve linear equations over rings, decide whether an ideal is maximal, find annihilators, and test the injectivity and surjectivity of ring homomorphisms. These problems appear to be hard classically.

  1. Systematic study of Optical Feshbach Resonances in an ideal gas

    E-print Network

    S. Blatt; T. L. Nicholson; B. J. Bloom; J. R. Williams; J. W. Thomsen; P. S. Julienne; J. Ye

    2011-06-06

    Using a narrow intercombination line in alkaline earth atoms to mitigate large inelastic losses, we explore the Optical Feshbach Resonance (OFR) effect in an ultracold gas of bosonic $^{88}$Sr. A systematic measurement of three resonances allows precise determinations of the OFR strength and scaling law, in agreement with coupled-channels theory. Resonant enhancement of the complex scattering length leads to thermalization mediated by elastic and inelastic collisions in an otherwise ideal gas. OFR could be used to control atomic interactions with high spatial and temporal resolution.

  2. Thermal transport through non-ideal Andreev quantum dots

    NASA Astrophysics Data System (ADS)

    Vidal, Pedro

    2015-07-01

    We consider the scenario of thermal transport through two types of Andreev quantum dots which are coupled to two leads, belonging to the Class D and Class C symmetry classes. Using the random matrix description we derive the joint probability density function (JPDF) in terms of hypergeometric function of matrix arguments when we consider one lead to be attached ideally and one lead non ideally. For the Class C ensemble we derive a more explicit representation of the JPDF which results in a new type of random matrix model.

  3. Thermal transport through non-ideal Andreev quantum dots

    E-print Network

    Pedro Vidal

    2015-01-07

    We consider the scenario of thermal transport through two types of Andreev quantum dots which are coupled to two leads, belonging to the Class D and Class C symmetry classes. Using the random matrix description we derive the joint probability density function (j.p.d.f.) in term of Hypergeometric Function of Matrix Arguments when we consider one lead to be attached ideally and one lead non ideally. For the class C ensemble we derive a more explicit representation of the j.p.d.f. which results in a new type of random matrix model.

  4. Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

    E-print Network

    Sanner, Christian Burkhard

    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes ...

  5. Exact solutions of Einstein's equations with ideal gas sources

    NASA Astrophysics Data System (ADS)

    Sussman, R. A.; Triginer, J.

    1999-01-01

    We derive a new class of exact solutions characterized by the Szekeres-Szafron metrics (of class I), admitting in general no isometries. The source is a fluid with viscosity but zero heat flux (adiabatic but irreversible evolution) whose equilibrium state variables satisfy the equations of state of: (a) an ultra-relativistic ideal gas; (b) a non-relativistic ideal gas; (c) a mixture of (a) and (b). Einstein's field equations reduce to a quadrature that is integrable in terms of elementary functions (cases (a) and (c)) and elliptic integrals (case (b)). Necessary and sufficient conditions are provided for the viscous dissipative stress and equilibrium variables to be consistent with the theoretical framework of extended irreversible thermodynamics and kinetic theory of the Maxwell-Boltzmann and radiative gases. Energy and regularity conditions are discussed. We prove that a smooth matching can be performed along a spherical boundary with a Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology or with a Vaidya exterior solution. Possible applications are briefly outlined.

  6. Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

    SciTech Connect

    Sanner, Christian; Su, Edward J.; Keshet, Aviv; Gommers, Ralf; Shin, Yong-il; Huang Wujie; Ketterle, Wolfgang [MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, and Department of Physics, Massachusetts Institute of Technology, Cambridge Massachusetts 02139 (United States)

    2010-07-23

    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10 000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.

  7. Parametric optimum analysis of an irreversible Ericsson cryogenic refrigeration cycle working with an ideal Fermi gas

    NASA Astrophysics Data System (ADS)

    Lin, Bihong; Zhao, Yingru; Chen, Jincan

    2008-05-01

    An irreversible model of an Ericsson cryogenic refrigeration cycle working with an ideal Fermi gas is established, which is composed of two isothermal and two isobaric processes. The influence of both the quantum degeneracy and the finite-rate heat transfer between the working fluid and the heat reservoirs on the performance of the cycle is investigated, based on the theory of statistical mechanics and thermodynamic properties of an ideal Fermi gas. The inherent regeneration losses of the cycle are analyzed. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the cycle is optimized for a given power input. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal regions of the coefficient of performance and power input are determined. Especially, the optimal performance of the cycle in the strong and weak gas degeneracy cases and the high temperature limit is discussed in detail. The analytic expressions of some optimized parameters are derived. Some optimum criteria are given. The distinctions and connections between the Ericsson refrigeration cycles working with the Fermi and classical gases are revealed.

  8. Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals

    NASA Technical Reports Server (NTRS)

    Burcat, A.; Zeleznik, F. J.; Mcbride, B. J.

    1985-01-01

    Ideal gas thermodynamic properties of the phenyl and o-biphenyl radicals, their deuterated analogs and the phenoxy radical were calculated to 5000 K using estimated vibrational frequencies and structures. The ideal gas thermodynamic properties of benzene, biphenyl, their deuterated analogs and phenyl were also calculated.

  9. Quantum arrival and dwell times via idealized clocks

    SciTech Connect

    Yearsley, J. M.; Downs, D. A.; Halliwell, J. J.; Hashagen, A. K. [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

    2011-08-15

    A number of approaches to the problem of defining arrival- and dwell-time probabilities in quantum theory makes use of idealized models of clocks. An interesting question is the extent to which the probabilities obtained in this way are related to standard semiclassical results. In this paper, we explore this question using a reasonably general clock model, solved using path-integral methods. We find that, in the weak-coupling regime, where the energy of the clock is much less than the energy of the particle it is measuring, the probability for the clock pointer can be expressed in terms of the probability current in the case of arrival times, and the dwell-time operator in the case of dwell times, the expected semiclassical results. In the regime of strong system-clock coupling, we find that the arrival-time probability is proportional to the kinetic-energy density, consistent with an earlier model involving a complex potential. We argue that, properly normalized, this may be the generically expected result in this regime. We show that these conclusions are largely independent of the form of the clock Hamiltonian.

  10. PHYSICAL REVIEW A 87, 043629 (2013) Pauli paramagnetism of an ideal Fermi gas

    E-print Network

    2013-01-01

    PHYSICAL REVIEW A 87, 043629 (2013) Pauli paramagnetism of an ideal Fermi gas Ye-Ryoung Lee,1 Tout T. Wang,1,2 Timur M. Rvachov,1 Jae-Hoon Choi,1 Wolfgang Ketterle,1 and Myoung-Sun Heo1,* 1 MIT, such as ideal, noninteracting gases that do not exist in nature. For example, several phenomena related to Pauli

  11. The Ideal Gas and Real Gas Heat Capacity of Sodium Atoms

    NASA Astrophysics Data System (ADS)

    Biolsi, Louis

    2014-10-01

    The ideal gas heat capacity of sodium atoms in the vapor phase is calculated to high temperatures using statistical mechanics. Since there are, in principle, an infinite number of atomic energy levels, the partition function and the heat capacity will grow very large unless the summation over energy levels is constrained as temperature increases. At higher temperatures, the increasing size of the atoms, which is a consequence of the increased population of highly excited energy levels, is used as a mechanism for limiting the summation over energy levels. The "" and "Bethe" procedures for cutting off the summation over energy levels will be discussed, and the results obtained using the two methods will be compared. In addition, although experimental information is available about lower atomic energy levels and some theoretical calculations are available for excited energy levels, information is lacking for most individual atomic states associated with highly excited energy levels. A "fill" procedure for approximating the energy of the unknown states will be discussed. Sodium vapor will also be considered to be a real gas that obeys the virial equation of state. The first non-ideal term in the power series expansion of the heat capacity in terms of virial coefficients involves the second virial coefficient, . This depends on the interaction potential energy between two sodium atoms, i.e., the potential energy curves for the sodium dimer. Accurate interaction potential energies can be obtained from either experimental or theoretical information for the lowest ten electronic states of the sodium dimer. These are used to calculate for each state, and the averaged value of for all ten states is used to calculate the non-ideal contribution to the heat capacity of sodium atoms as a function of temperature.

  12. On the structure of MHD shock waves in a viscous non-ideal gas

    NASA Astrophysics Data System (ADS)

    Anand, R. K.; Yadav, Harish C.

    2014-06-01

    The structure of one-dimensional magnetohydrodynamics (MHD) shock waves is studied using the Navier-Stokes equations for the non-ideal gas phase. The exact solutions are obtained for the flow variables (i.e. particle velocity, temperature, pressure and change-in-entropy) within the shock transition region. The equation of state for a non-ideal gas is considered as given by Landau and Lifshitz. The effects of the non-idealness parameter and coefficient of viscosity of the gas are analysed on the flow variables assuming the magnetic field having only constant axial component. The findings confirm that the thickness of MHD shock front increases with decreasing values of the non-idealness parameter.

  13. A Systematic Experimental Test of the Ideal Gas Equation for the General Chemistry Laboratory

    NASA Astrophysics Data System (ADS)

    Blanco, Luis H.; Romero, Carmen M.

    1995-10-01

    A set of experiments that examines each one of the terms of the ideal gas equation is described. Boyle's Law, Charles-Gay Lussac's Law, Amonton's Law, the number of moles or Molecular Weight, and the Gas Constant are studied. The experiments use very simple, easy to obtain equipment and common gases, mainly air. The results gathered by General Chemistry College students are satisfactory.

  14. Shock dynamics of strong imploding cylindrical and spherical shock waves with non-ideal gas effects

    E-print Network

    Anand, R K

    2013-01-01

    In this paper, the generalized analytical solution for one dimensional adiabatic flow behind the strong imploding shock waves propagating in a non-ideal gas is obtained by using the geometrical shock dynamics theory. The equation of state for non-ideal gas as given by Landau and Lifshitz and the generalized shock jump relations derived by Anand are taken into consideration to explore the effects due to an increase in (i) the propagation distance from the centre of convergence, (ii) the non-idealness parameter and, (iii) the adiabatic index, on the shock velocity, pressure, density, particle velocity, sound speed, adiabatic compressibility and the change in entropy across the shock front. The findings provided a clear picture of whether and how the non-idealness parameter and the adiabatic index affect the flow field behind the strong imploding shock front.

  15. Ultracold strongly coupled gas: A near-ideal liquid

    SciTech Connect

    Gelman, Boris A.; Shuryak, Edward V.; Zahed, Ismail [Department of Physics and Astronomy, State University of New York, Stony Brook, New York 11794-3800 (United States)

    2005-10-15

    Feshbach resonances of trapped ultracold alkali-metal atoms allow to vary the atomic scattering length a. At very large values of a the system enters an universal strongly coupled regime in which its properties--the ground-state energy, pressure, etc.--become independent of a. We discuss the transport properties of such systems. In particular, the universality arguments imply that the shear viscosity of ultracold Fermi atoms at the Feschbach resonance is proportional to the particle number density n and the Plank constant ({Dirac_h}/2{pi}): {eta}=({Dirac_h}/2{pi})n{alpha}{sub {eta}}, where {alpha}{sub {eta}} is a universal constant. Using Heisenberg uncertainty principle and Einstein's relation between diffusion and viscosity we argue that the viscosity has the lower bound given by {alpha}{sub {eta}}{<=}(6{pi}){sup -1}. We relate the damping of low-frequency density oscillations of ultracold optically trapped {sup 6}Li atoms to viscosity and find that the value of the coefficient {alpha}{sub {eta}} is about 0.3. We also show that such a small viscosity cannot be explained by kinetic theory based on binary scattering. We conclude that the system of ultracold atoms near the Feshbach resonance is a near-ideal liquid.

  16. A Unified Theory of Non-Ideal Gas Lattice Boltzmann Models

    NASA Technical Reports Server (NTRS)

    Luo, Li-Shi

    1998-01-01

    A non-ideal gas lattice Boltzmann model is directly derived, in an a priori fashion, from the Enskog equation for dense gases. The model is rigorously obtained by a systematic procedure to discretize the Enskog equation (in the presence of an external force) in both phase space and time. The lattice Boltzmann model derived here is thermodynamically consistent and is free of the defects which exist in previous lattice Boltzmann models for non-ideal gases. The existing lattice Boltzmann models for non-ideal gases are analyzed and compared with the model derived here.

  17. The effect of the reference frame on the thermophysical properties of an ideal gas

    SciTech Connect

    Speziale, Cg.

    1986-01-01

    The effect that the frame of reference has on the thermophysical properties of an ideal gas is examined from a fundamental theoretical standpoint based on the Boltzmann equation. In continuum mechanics, the principle of material frame in deference forbids the thermophysical properties of a fluid or solid to depend in any way on the motion of the reference frame. It is demonstrated that the Boltzmann equation is only consistent with material frame-indeffrence in a strong approximate sense provided that the gas is not highly rarefield and, thus, well within the limits of classical continuum mechanics. Estimates of the mean free times for which material frame-indifference can be invoked in the modeling of gas flows are provided from an analysis of the problem of heat conduction in a rigidly rotating gas. Applications of these results in obtaining asymptotic solutions of the Boltzmann equation for the continuum description of an ideal gas are discussed briefly.

  18. The effect of the reference frame on the thermophysical properties of an ideal gas

    NASA Astrophysics Data System (ADS)

    Speziale, C. G.

    1986-01-01

    The effect that the frame of reference has on the thermophysical properties of an ideal gas is examined from a fundamental theoretical standpoint based on the Boltzmann equation. In continuum mechanics, the principle of material frame-indifference forbids the thermophysical properties of a fluid or solid to depend in any way on the motion of the reference frame. It is demonstrated that the Boltzmann equation is only consistent with material frame-indifference in a strong approximate sense provided that the gas is not highly rarefied and, thus, well within the limits of classical continuum mechanics. Estimates of the mean free times for which material frame-indifference can be invoked in the modeling of gas flows are provided from an analysis of the problem of heat conduction in a rigidly rotating gas. Applications of these results in obtaining asymptotic solutions of the Boltzmann equation for the continuum description of an ideal gas are discussed briefly.

  19. Transient temperature measurements in an ideal gas by laser-induced Rayleigh light scattering

    Microsoft Academic Search

    J. F. Horton; J. E. Peterson

    1999-01-01

    A laser-induced Rayleigh light-scattering (RLS) system was assembled and used to noninvasively measure the transient molecular number density in an ideal gas. This information was used to find the transient gas temperature when operating at known pressure. The laser was a 4 W argon ion operating on all lines at a total power of about 2.5 W. The theoretically predicted

  20. Fluctuation theorem for entropy production during effusion of an ideal gas with momentum transfer

    E-print Network

    Kawai, Ryoichi

    , for example, the theory of linear irreversible processes 2 and the fluctuation- dissipation theorem 3 . OverFluctuation theorem for entropy production during effusion of an ideal gas with momentum transfer and explicitly verify the thermo- dynamic fluctuation theorem, thereby directly exhibiting its extended

  1. The effect of the reference frame on the thermophysical properties of an ideal gas

    Microsoft Academic Search

    C. G. Speziale

    1986-01-01

    The effect that the frame of reference has on the thermophysical properties of an ideal gas is examined from a fundamental theoretical standpoint based on the Boltzmann equation. In continuum mechanics, the principle of material frame-indifference forbids the thermophysical properties of a fluid or solid to depend in any way on the motion of the reference frame. It is demonstrated

  2. CHAPTER 6 -PERIODIC BOUNDARIES In considering an ideal gas, we didn't worry about whether our numerical

    E-print Network

    Boal, David

    to the ideal gas law. Because it is more common to Chapter 6 - Periodic boundaries 78 ©1997 by David BoalCHAPTER 6 - PERIODIC BOUNDARIES In considering an ideal gas, we didn't worry about whether our is the use of periodic boundaries, in which a given sample is surrounded by replicas of itself

  3. Low-temperature behaviour of an ideal Bose gas and some forbidden thermodynamic cycles

    NASA Astrophysics Data System (ADS)

    Chen, Jincan; Lin, Bihong

    2003-11-01

    Based on the equation of state of an ideal Bose gas, the heat capacities at constant volume and constant pressure of the Bose system are derived and used to analyse the low-temperature behaviour of the Bose system. It is expounded that some important thermodynamic processes such as a constant pressure and an adiabatic process cannot be carried out from the region of T > Tc to that of T < Tc, where Tc is the critical temperature of Bose-Einstein condensation of the Bose system. Consequently, some typical thermodynamic cycles such as the Carnot cycle, Brayton cycle, Otto cycle, Ericsson cycle, Diesel cycle and Atkinson cycle cannot be operated across the critical temperature Tc of Bose-Einstein condensation of an ideal Bose gas.

  4. Thermodynamic instability and first-order phase transition in an ideal Bose gas

    SciTech Connect

    Park, Jeong-Hyuck [Department of Physics and Center for Quantum Spacetime Sogang University, Mapo-gu, Seoul 121-742 (Korea, Republic of); Kim, Sang-Woo [High Energy Accelerator Research Organization (KEK) Tsukuba, Ibaraki 305-0801 (Japan)

    2010-06-15

    We conduct a rigorous investigation into the thermodynamic instability of an ideal Bose gas confined in a cubic box, without assuming a thermodynamic limit or a continuous approximation. Based on the exact expression of the canonical partition function, we perform numerical computations up to 10{sup 6} particles. We report that if the number of particles is equal to or greater than a certain critical value, which turns out to be 7616, the ideal Bose gas subject to the Dirichlet boundary condition reveals a thermodynamic instability. Accordingly, we demonstrate that a system consisting of a finite number of particles can exhibit a discontinuous phase transition that features a genuine mathematical singularity, provided we keep not volume but pressure constant. The specific number, 7616, can be regarded as a characteristic number of a ''cube,'' which is the geometric shape of the box.

  5. Non-linear radial accretion of an ideal gas onto a spherically symmetric black hole

    NASA Astrophysics Data System (ADS)

    Gracia-Linares, M.; Guzmán, F. S.; Lora-Clavijo, F. D.

    2013-07-01

    We solve numerically the Einstein-Euler system of equations for a perfect fluid with an ideal gas equation of state, moving radially toward a spherically symmetric black hole. In order to do so we use the 3+1 decomposition of space-time with the ADM formulation of general relativity. In particular we study the growth of the event horizon and verify the convergence of our code.

  6. Condensation of N bosons. II. Nonequilibrium analysis of an ideal Bose gas and the laser phase-transition analogy 

    E-print Network

    Kocharovsky, VV; Scully, Marlan O.; Zhu, S. Y.; Zubairy, M. Suhail

    2000-01-01

    A nonequilibrium approach to the dynamics and statistics of the condensate of an ideal N-atom Bose gas cooling via interaction with a thermal reservoir using the canonical ensemble is developed. We derive simple analytical expressions...

  7. A complete theory for the magnetism of an ideal gas of electrons

    SciTech Connect

    Biswas, Shyamal; Jana, Debnarayan [Department of Physics, University of Calcutta, 92 APC Road, Kolkata 700009 (India)] [Department of Physics, University of Calcutta, 92 APC Road, Kolkata 700009 (India); Sen, Swati [Department of Physical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur 741252 (India)] [Department of Physical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur 741252 (India)

    2013-05-15

    We have explored Pauli paramagnetism, Landau diamagnetism, and de Haas-van Alphen effect in a single framework, and unified these three effects for all temperatures as well as for all strengths of magnetic field. Our result goes beyond Pauli-Landau result on the magnetism of the 3-D ideal gas of electrons, and is able to describe crossover of the de Haas-van Alphen oscillation to the saturation of magnetization. We also have obtained a novel asymptotic series expansion for the low temperature properties of the system.

  8. Experimental Demonstration of Quantum Lattice Gas Computation

    Microsoft Academic Search

    Marco A. Pravia; Zhiying Chen; Jeffrey Yepez; David G. Cory

    2003-01-01

    We report an ensemble nuclear magnetic resonance (NMR) implementation of a quantum lattice gas algorithm for the diffusion equation. The algorithm employs an array of quantum information processors sharing classical information, a novel architecture referred to as a type-II quantum computer. This concrete implementation provides a test example from which to probe the strengths and limitations of this new computation

  9. Experimental Demonstration of Quantum Lattice Gas Computation

    Microsoft Academic Search

    Marco A. Pravia; Zhiying Chen; Jeffrey Yepez; David G. Cory

    2003-01-01

    We report an ensemble nuclear magnetic resonance (NMR) implementation of a quantum lattice gas algorithm for the diffusion equation. The algorithm employs an array of quantum information processors sharing classical information, a novel architecture referred to as a type-II quantum computer. This concrete implementa-tion provides a test example from which to probe the strengths and limitations of this new computation

  10. Gas-Kinetic Theory Based Flux Splitting Method for Ideal Magnetohydrodynamics

    NASA Technical Reports Server (NTRS)

    Xu, Kun

    1998-01-01

    A gas-kinetic solver is developed for the ideal magnetohydrodynamics (MHD) equations. The new scheme is based on the direct splitting of the flux function of the MHD equations with the inclusion of "particle" collisions in the transport process. Consequently, the artificial dissipation in the new scheme is much reduced in comparison with the MHD Flux Vector Splitting Scheme. At the same time, the new scheme is compared with the well-developed Roe-type MHD solver. It is concluded that the kinetic MHD scheme is more robust and efficient than the Roe- type method, and the accuracy is competitive. In this paper the general principle of splitting the macroscopic flux function based on the gas-kinetic theory is presented. The flux construction strategy may shed some light on the possible modification of AUSM- and CUSP-type schemes for the compressible Euler equations, as well as to the development of new schemes for a non-strictly hyperbolic system.

  11. Analytical pair correlations in ideal quantum gases: temperature-dependent bunching and antibunching.

    PubMed

    Bosse, J; Pathak, K N; Singh, G S

    2011-10-01

    The fluctuation-dissipation theorem together with the exact density response spectrum for ideal quantum gases has been utilized to yield a new expression for the static structure factor, which we use to derive exact analytical expressions for the temperature-dependent pair distribution function g(r) of the ideal gases. The plots of bosonic and fermionic g(r) display "Bose pile" and "Fermi hole" typically akin to bunching and antibunching as observed experimentally for ultracold atomic gases. The behavior of spin-scaled pair correlation for fermions is almost featureless, but bosons show a rich structure including long-range correlations near T(c). The coherent state at T=0 shows no correlation at all, just like single-mode lasers. The depicted decreasing trend in correlation with decrease in temperature for T

  12. Two Approaches to Fractional Statistics in the Quantum Hall Effect: Idealizations and the Curious Case of the Anyon

    NASA Astrophysics Data System (ADS)

    Shech, Elay

    2015-04-01

    This paper looks at the nature of idealizations and representational structures appealed to in the context of the fractional quantum Hall effect, specifically, with respect to the emergence of anyons and fractional statistics. Drawing on an analogy with the Aharonov-Bohm effect, it is suggested that the standard approach to the effects—(what we may call) the topological approach to fractional statistics—relies essentially on problematic idealizations that need to be revised in order for the theory to be explanatory. An alternative geometric approach is outlined and endorsed. Roles for idealizations in science, as well as consequences for the debate revolving around so-called essential idealizations, are discussed.

  13. Quantum lattice gas representation for vector solitons

    Microsoft Academic Search

    George Vahala; Linda Vahala; Jeffrey Yepez

    2003-01-01

    Quantum lattice gas algorithms are developed for the coupled-nonlinear Schrodinger (coupled-NLS) equations, equations that describe the propagation of pulses in birefringent fibers. When the cross-phase modulation factor is unity, the coupled-NLS reduce to the Manakov equations. The quantum lattice gas algorithm yields vector solitons for the fully integrable Manakov system that are in excellent agreement with exact results. Simulations are

  14. Fluctuating ideal-gas lattice Boltzmann method with fluctuation dissipation theorem for nonvanishing velocities.

    PubMed

    Kaehler, G; Wagner, A J

    2013-06-01

    Current implementations of fluctuating ideal-gas descriptions with the lattice Boltzmann methods are based on a fluctuation dissipation theorem, which, while greatly simplifying the implementation, strictly holds only for zero mean velocity and small fluctuations. We show how to derive the fluctuation dissipation theorem for all k, which was done only for k=0 in previous derivations. The consistent derivation requires, in principle, locally velocity-dependent multirelaxation time transforms. Such an implementation is computationally prohibitively expensive but, with a small computational trick, it is feasible to reproduce the correct FDT without overhead in computation time. It is then shown that the previous standard implementations perform poorly for non vanishing mean velocity as indicated by violations of Galilean invariance of measured structure factors. Results obtained with the method introduced here show a significant reduction of the Galilean invariance violations. PMID:23848809

  15. University Students Explaining Adiabatic Compression of an Ideal Gas--A New Phenomenon in Introductory Thermal Physics

    ERIC Educational Resources Information Center

    Leinonen, Risto; Asikainen, Mervi A.; Hirvonen, Pekka E.

    2012-01-01

    This study focuses on second-year university students' explanations and reasoning related to adiabatic compression of an ideal gas. The phenomenon was new to the students, but it was one which they should have been capable of explaining using their previous upper secondary school knowledge. The students' explanations and reasoning were…

  16. Transport phenomena and conservation equations in multicomponent chemically-reactive ideal gas mixtures

    SciTech Connect

    Sohrab, S.H. [Northwestern Univ., Evanston, IL (United States)

    1996-12-01

    The symmetric forms of the conservation equations for mass, energy, and momentum in reactive ideal gas mixtures are presented. A modified form of the continuity equation is introduced which accounts for possible diffusion of mass under the gradient of density in simple fluids, similar to the Smoluchowski equation describing the Brownian motion of small particles suspended in a fluid subject to an external force. An intermediate statistical field called cluster-dynamics is postulated and the statistically-stationary nature of the Brownian motions of small suspensions in stationary fluids is attributed to the fact that the suspensions are in equilibrium with molecular-clusters, that themselves possess Brownian motions. The Newton law of viscosity is generalized through the introduction of momentum diffusion velocity V{sub ij} and the rate of stress tensor is defined in terms of the corresponding diffusional flux of momenta. A modified form of the Navier-Stokes equation is presented that includes a source (sink) of momentum caused by heat release (absorption) associated with exothermic (endothermic) chemical reactions. The equivalence between the modified and the original forms of the Navier-Stokes equation is established. The symmetric forms of the conservation equations, in the absence of dissipations, are then used to derive four wave equations which describe the propagation of density, temperature, pressure, and velocity perturbations at the cluster-dynamic scale. The results may provide certain guidelines towards the identification of a scale-invariant statistical theory of turbulence in chemically-reactive hydrodynamic fields. 35 refs.

  17. Experimental Demonstration of Quantum Lattice Gas Computation

    Microsoft Academic Search

    Marco A. Pravia; Zhiying Chen; David G. Cory; Jeffrey Yepez

    2003-01-01

    We report an ensemble nuclear magnetic resonance (NMR) implementation of a\\u000aquantum lattice gas algorithm for the diffusion equation. The algorithm employs\\u000aan array of quantum information processors sharing classical information, a\\u000anovel architecture referred to as a type-II quantum computer. This concrete\\u000aimplementation provides a test example from which to probe the strengths and\\u000alimitations of this new computation

  18. On the power cycles working with ideal quantum gases: I. The Ericsson cycle

    NASA Astrophysics Data System (ADS)

    Sisman, Altug; Saygin, Hasan

    1999-03-01

    The Ericsson power cycles working with ideal Bose and Fermi monoatomic gases are examined. They are conveniently called the Bose and Fermi cycles. Efficiencies of Bose and Fermi cycles are derived (0022-3727/32/6/011/img1 and 0022-3727/32/6/011/img2 respectively). Variations of them with the temperature ratio 0022-3727/32/6/011/img3 and pressure ratio of the cycle are examined. A comparison of the efficiencies with each other and that of the classical Ericsson cycle 0022-3727/32/6/011/img4 is made. In the degenerate gas state it is seen that 0022-3727/32/6/011/img5, although 0022-3727/32/6/011/img6 in the classical gas state. In a Bose cycle, it is shown that there is an optimum value for the lowest temperature 0022-3727/32/6/011/img7 at which the efficiency reaches its maximum value for a given pressure ratio. Furthermore, Bose-Einstein condensation restricts the value of 0022-3727/32/6/011/img8 of a Bose cycle for a given value of 0022-3727/32/6/011/img9. In a Fermi cycle, there is no an optimum value for 0022-3727/32/6/011/img8. However, 0022-3727/32/6/011/img2 goes to a finite value of less than unity when 0022-3727/32/6/011/img12 goes to zero.

  19. Preparation of a Pure Molecular Quantum Gas

    Microsoft Academic Search

    Jens Herbig; Tobias Kraemer; Michael Mark; Tino Weber; Cheng Chin; Hanns-Christoph Nägerl; Rudolf Grimm

    2003-01-01

    An ultracold molecular quantum gas is created by application of a magnetic field sweep across a Feshbach resonance to a Bose-Einstein condensate of cesium atoms. The ability to separate the molecules from the atoms permits direct imaging of the pure molecular sample. Magnetic levitation enables study of the dynamics of the ensemble on extended time scales. We measured ultralow expansion

  20. Experimental Demonstration of Quantum Lattice Gas Computation

    E-print Network

    Marco A. Pravia; Zhiying Chen; Jeffrey Yepez; David G. Cory

    2003-03-31

    We report an ensemble nuclear magnetic resonance (NMR) implementation of a quantum lattice gas algorithm for the diffusion equation. The algorithm employs an array of quantum information processors sharing classical information, a novel architecture referred to as a type-II quantum computer. This concrete implementation provides a test example from which to probe the strengths and limitations of this new computation paradigm. The NMR experiment consists of encoding a mass density onto an array of 16 two-qubit quantum information processors and then following the computation through 7 time steps of the algorithm. The results show good agreement with the analytic solution for diffusive dynamics. We also describe numerical simulations of the NMR implementation. The simulations aid in determining sources of experimental errors, and they help define the limits of the implementation.

  1. Test particle in a quantum gas

    SciTech Connect

    Vacchini, Bassano

    2001-06-01

    A master equation with a Lindblad structure is derived, which describes the interaction of a test particle with a macroscopic system and is expressed in terms of the operator valued dynamic structure factor of the system. In the case of a free Fermi or Bose gas the result is evaluated in the Brownian limit, thus obtaining a single generator master equation for the description of quantum Brownian motion in which the correction due to quantum statistics is explicitly calculated. The friction coefficients for Boltzmann and Bose or Fermi statistics are compared.

  2. A new method for the measurement of meteorite bulk volume via ideal gas pycnometry

    NASA Astrophysics Data System (ADS)

    Li, Shijie; Wang, Shijie; Li, Xiongyao; Li, Yang; Liu, Shen; Coulson, Ian M.

    2012-10-01

    To date, of the many techniques used to measure the bulk volume of meteorites, only three methods (Archimedean bead method, 3-D laser imaging and X-ray microtomography) can be considered as nondestructive or noncontaminating. The bead method can show large, random errors for sample sizes of smaller than 5 cm3. In contrast, 3-D laser imaging is a high-accuracy method even when measuring the bulk volumes of small meteorites. This method is both costly and time consuming, however, and meteorites of a certain shape may lead to some uncertainties in the analysis. The method of X-ray microtomography suffers from the same problems as 3-D laser imaging. This study outlines a new method of high-accuracy, nondestructive and noncontaminating measurement of the bulk volume of meteorite samples. In order to measure the bulk volume of a meteorite, one must measure the total volume of the balloon vacuum packaged meteorite and the volume of balloon that had been used to enclose the meteorite using ideal gas pycnometry. The difference between the two determined volumes is the bulk volume of the meteorite. Through the measurement of zero porosity metal spheres and tempered glass fragments, our results indicate that for a sample which has a volume of between 0.5 and 2 cm3, the relative error of the measurement is less than ±0.6%. Furthermore, this error will be even smaller (less than ±0.1%) if the determined sample size is larger than 2 cm3. The precision of this method shows some volume dependence. For samples smaller than 1 cm3, the standard deviations are less than ±0.328%, and these values will fall to less than ±0.052% for samples larger than 2 cm3. The porosities of nine fragments of Jilin, GaoGuenie, Zaoyang and Zhaodong meteorites have been measured using our vacuum packaging-pycnometry method, with determined average porosities of Jilin, GaoGuenie, Zaoyang and Zhaodong of 9.0307%, 2.9277%, 17.5437% and 5.9748%, respectively. These values agree well with the porosities of fragments of which have been measured using the Archimedean bead method and 3-D laser imaging. This method also may be applied to the study of rare samples in other fields (e.g., archeology and geology).

  3. Quantum Behavior of an Atomic Fermi Gas

    Microsoft Academic Search

    Brian Demarco

    2002-01-01

    The magnetic trapping and evaporative cooling techniques used to produce atomic Bose-Einstein condensation were extended to create the first quantum degenerate Fermi gas of atoms. Evaporatively cooling fermionic atoms is hindered by the fundamental difficulty that identical fermionic atoms do not collide at ultra-cold temperatures (less than a few 100 muK). This complication was overcome by magnetically trapping two spin-states

  4. Unitary Quantum Lattice Gas Algorithms for Quantum to Classical Turbulence

    Microsoft Academic Search

    George Vahala; Jeffrey Yepez; Min Soe; Linda Vahala; Sean Ziegeler

    2010-01-01

    Using a set of interleaved unitary collision-stream operators, a three-dimensional (3D) quantum lattice gas algorithm is devised which, on taking moments, recovers the Gross-Pitaevskii (GP) equation. If a zerotemperature Bose-Einstein condensate (BEC) is trapped in an a magnetic well, the evolution of the ground-state wave function satisfies the scalar GP equation; while if the BEC is trapped in an optical

  5. Quantum Behavior of an Atomic Fermi Gas

    NASA Astrophysics Data System (ADS)

    Demarco, Brian

    2002-05-01

    The magnetic trapping and evaporative cooling techniques used to produce atomic Bose-Einstein condensation were extended to create the first quantum degenerate Fermi gas of atoms. Evaporatively cooling fermionic atoms is hindered by the fundamental difficulty that identical fermionic atoms do not collide at ultra-cold temperatures (less than a few 100 ?K). This complication was overcome by magnetically trapping two spin-states of the fermionic atom ^40K which undergo the s-wave collisions necessary for rethermalization during cooling. The unique properties of binary collisions of fermionic atoms were used to make the first measurement of the ^40K s-wave triplet scattering length. In particular, by varying the spin mixture of the gas the effect of p-wave and s-wave collisions on rethermalization could be separated at low temperature. The simultaneous measurement of two partial wave collision cross-sections enabled a precise determination of the triplet scattering length, a parameter crucial to cold collision theory. In addition, we made one of the first measurements of the Wigner threshold law for p-wave collisions of neutral scatterers. A novel two-component cooling scheme was implemented to cool the gas into the quantum degenerate regime where the temperature T is less than the Fermi temperature T_F. The effects of quantum degeneracy were first observed in the thermodynamics of a spin-polarized gas. Not only did the gas possess higher energy than expected classically, but the momentum distribution of the gas deviated from the classical expectation. A model was developed of the evaporative cooling process in order understand the limitations of the cooling scheme. Technical improvements to the apparatus motivated by this model have led to progress farther into the degenerate regime (T/TF 0.2) with interacting (spin-mixed) gases. The thermodynamics of interacting gases was studied, and Pauli blocking (a non-local quantum phenomenon common to all Fermi systems) of collisions was observed through measurements of the dynamics of the spin-mixed gas.

  6. Mesoscopic Effects in Bose-Einstein Condensate Fluctuations of an Ideal Gas in a Box 

    E-print Network

    Dorfman, Konstantin Evgenievich

    2009-05-15

    The mesoscopic effects in the quantum trapped gases of the Bose atoms constitute the main subject of the present thesis. These effects are the most difficult for the theoretical analysis in the quantum statistical physics since they can’t be seen...

  7. Interferograms, Schlieren, and Shadowgraphs Constructed from Real- and Ideal-Gas, Two- and Three-Dimensional Computed Flowfields

    NASA Technical Reports Server (NTRS)

    Yates, Leslie A.

    1992-01-01

    The construction of interferograms, schlieren, and shadowgraphs from computed flowfield solutions permits one-to-one comparisons of computed and experimental results. A method for constructing these images from both ideal- and real-gas, two- and three-dimensional computed flowfields is described. The computational grids can be structured or unstructured, and multiple grids are an option. Constructed images are shown for several types of computed flows including nozzle, wake, and reacting flows; comparisons to experimental images are also shown. In addition, the sensitivity of these images to errors in the flowfield solution is demonstrated, and the constructed images can be used to identify problem areas in the computations.

  8. Interferograms, schlieren, and shadowgraphs constructed from real- and ideal-gas, two- and three-dimensional computed flowfields

    NASA Technical Reports Server (NTRS)

    Yates, Leslie A.

    1993-01-01

    The construction of interferograms, schlieren, and shadowgraphs from computed flowfield solutions permits one-to-one comparisons of computed and experimental results. A method of constructing these images from both ideal- and real-gas, two and three-dimensional computed flowfields is described. The computational grids can be structured or unstructured, and multiple grids are an option. Constructed images are shown for several types of computed flows including nozzle, wake, and reacting flows; comparisons to experimental images are also shown. In addition, th sensitivity of these images to errors in the flowfield solution is demonstrated, and the constructed images can be used to identify problem areas in the computations.

  9. Anomalous effective dimensionality of quantum gas adsorption near nanopores.

    PubMed

    Full, Steven J; McNutt, Jessica P; Cole, Milton W; Mbaye, Mamadou T; Gatica, Silvina M

    2010-08-25

    Three problems involving quasi-one-dimensional (1D) ideal gases are discussed. The simplest problem involves quantum particles localized within the 'groove', a quasi-1D region created by two adjacent, identical and parallel nanotubes. At low temperature (T), the transverse motion of the adsorbed gas, in the plane perpendicular to the axes of the tubes, is frozen out. Then, the low T heat capacity C(T) of N particles is that of a 1D classical gas: C(*)(T) = C(T)/(Nk(B)) --> 1/2. The dimensionless heat capacity C(*) increases when T ? 0.1T(x, y) (transverse excitation temperatures), asymptoting at C(*) = 2.5. The second problem involves a gas localized between two nearly parallel, co-planar nanotubes, with small divergence half-angle ?. In this case, too, the transverse motion does not contribute to C(T) at low T, leaving a problem of a gas of particles in a 1D harmonic potential (along the z axis, midway between the tubes). Setting ?(z) as the angular frequency of this motion, for T ? ?(z) ? ?(z)?/k(B), the behavior approaches that of a 2D classical gas, C(*) = 1; one might have expected instead C(*) = 1/2, as in the groove problem, since the limit ? ? 0 is 1D. For T < ?(z), the thermal behavior is exponentially activated, C(*) ? (?(z)/T)(2)e(-?(z)/T). At higher T (T ? ?(y)/k(B) ? ?(y) > ?(z)), motion is excited in the y direction, perpendicular to the plane of nanotubes, resulting in thermal behavior (C(*) = 7/4) corresponding to a gas in 7/2 dimensions, while at very high T (T > ??(x)/k(B) ? ?(x) > ?(y)), the behavior becomes that of a D = 11/2 system. The third problem is that of a gas of particles, e.g. (4)He, confined in the interstitial region between four square parallel pores. The low T behavior found in this case is again surprising--that of a 5D gas. PMID:21386496

  10. An idealized model for dust-gas interaction in a rotating channel

    E-print Network

    O. M. Umurhan

    2007-01-11

    A 2D model representing the dynamical interaction of dust and gas in a planetary channel is explored. The two components are treated as interpenetrating fluids in which the gas is treated as a Boussinesq fluid while the dust is treated as pressureless. The only coupling between both fluid states is kinematic drag. The channel gas experiences a temperature gradient in the spanwise direction and it is adverse the constant force of gravity. The latter effects only the gas and not the dust component which is considered to free float in the fluid. The channel is also considered on an f-plane so that the background vorticity gradient can cause any emerging vortex structure to drift like a Rossby wave. A linear theory analysis is explored and a nonlinear amplitude theory is developed for disturbances of this arrangement. It is found that the presence of the dust can help generate and shape emerging convection patterns and dynamics in the gas so long as the state of the gas exceeds a suitably defined Rayleigh number appropriate for describing drag effects. In the linear stage the dust particles collect quickly onto sites in the gas where the vorticity is minimal, i.e. where the disturbance vorticity is anticylonic which is consistent with previous studies. The nonlinear theory shows that, in turn, the local enhancement of dust concentration in the gas effects the vigor of the emerging convective roll by modifying the effective local Rayleigh number of the fluid. It is also found that without the f-plane approximation built into the model the dynamics there is an algebraic runaway caused by unrestrained growth in the dust concentration. The background vorticity gradient forces the convective roll to drift like a Rossby wave and this causes the dust concentration enhancements to not runaway.

  11. Peltier effect induced longitudinal resistivity of ideal 2D electron(hole) gas in strong magnetic field

    Microsoft Academic Search

    M. V. Cheremisin

    2000-01-01

    We demonstrate that in strong quantum limit the thermoelectric Peltier effect could define the longitudinal resistivity of dissipationless two-dimensional electron(hole) gas. The current results in heating(cooling) at first(second) Hall bar sample contact due to Peltier effect. At small current the contacts temperatures are different, the temperature gradient is linear on current. The voltage swing downstream the current is proportional to

  12. Ideal-Gas Heat Capacity for 2,3,3,3-Tetrafluoropropene (HFO-1234yf) Determined from Speed-of-Sound Measurements

    NASA Astrophysics Data System (ADS)

    Kano, Yuya; Kayukawa, Yohei; Fujii, Kenichi; Sato, Haruki

    2010-12-01

    The isobaric ideal-gas heat capacity for HFO-1234yf, which is expected to be one of the best alternative refrigerants for HFC-134a, was determined on the basis of speed-of-sound measurements in the gaseous phase. The speed of sound was measured by means of the acoustic resonance method using a spherical cavity. The resonance frequency in the spherical cavity containing the sample gas was measured to determine the speed of sound. After correcting for some effects such as the thermal boundary layer and deformation of the cavity on the resonance frequency, the speed of sound was obtained with a relative uncertainty of 0.01 %. Using the measured speed-of-sound data, the acoustic-virial equation was formulated and the isobaric ideal-gas heat capacity was determined with a relative uncertainty of 0.1 %. A temperature correlation function of the isobaric ideal-gas heat capacity for HFO-1234yf was also developed.

  13. First Law of Thermodynamics Two closed thermodynamic cycles for an ideal gas

    E-print Network

    Winokur, Michael

    positive because W is negative and U = W + Q = 0 Demo:steam engine #12;2 A cylinder with initial volume V convertible has an eight-cylinder engine. At the beginning of its compression stroke, one of the cylinders.72 x 106 Pa. What is the final temperature of the gas in an engine cylinder after the compression

  14. Quantum Lattice Gas Algorithm for the Coupled Nonlinear Schrodinger Equation

    Microsoft Academic Search

    George Vahala; Linda Vahala; Jeffrey Yepez

    2003-01-01

    Quantum computers hold the promise of exponential speed-up over classical computers when quantum entanglement plays a significant role in the algorithm. Here we extend our quantum lattice gas algorithm for the nonlinear Schrodinger equation (NLS) to the Manakov equations. Under certain conditions, the Manakov equations describe the nonlinear interaction between the orthogonal polarization components of an electromagnetic wave propagating in

  15. Quantum Lattice-Gas Model for the Diffusion Equation

    Microsoft Academic Search

    Jeffrey Yepez

    2001-01-01

    Presented is a factorized quantum lattice-gas algorithm to model the diffusion equation. It is a minimal model with two qubits per node of a one-dimensional lattice and it is suitable for implementation on a large array of small quantum computers interconnected by nearest-neighbor classical communication channels. The quantum lattice-gas system is described at the mesoscopic scale by a lattice-Boltzmann equation

  16. Idealized gas turbine combustor for performance research and validation of large eddy simulations

    NASA Astrophysics Data System (ADS)

    Williams, Timothy C.; Schefer, Robert W.; Oefelein, Joseph C.; Shaddix, Christopher R.

    2007-03-01

    This paper details the design of a premixed, swirl-stabilized combustor that was designed and built for the express purpose of obtaining validation-quality data for the development of large eddy simulations (LES) of gas turbine combustors. The combustor features nonambiguous boundary conditions, a geometrically simple design that retains the essential fluid dynamics and thermochemical processes that occur in actual gas turbine combustors, and unrestrictive access for laser and optical diagnostic measurements. After discussing the design detail, a preliminary investigation of the performance and operating envelope of the combustor is presented. With the combustor operating on premixed methane/air, both the equivalence ratio and the inlet velocity were systematically varied and the flame structure was recorded via digital photography. Interesting lean flame blowout and resonance characteristics were observed. In addition, the combustor exhibited a large region of stable, acoustically clean combustion that is suitable for preliminary validation of LES models.

  17. Development Of Excel Add-in Modules For Use In Thermodynamics Curriculum: Steam And Ideal Gas Properties

    NSDL National Science Digital Library

    Huguet, Jesse

    For engineering graduates entering the job market, experience with appropriate computational tools and techniques is increasingly necessary. Therefore, the University of Alabama's Mechanical Engineering Department is introducing students to computational problem solving earlier in their college careers by developing Microsoft Excel-based modules to be used as teaching tools in the sophomore and junior-level thermodynamics and heat transfer courses. The MS Excel package was chosen as a software platform for this purpose because of its ubiquitous nature and its ability to utilize Visual Basic for Applications (VBA) macros in a spreadsheet format. In the sophomore-level thermodynamics course, much of the class material focuses on the properties of steam and ideal gases. Therefore, a suite of Microsoft Excel functions to compute steam and ideal gas properties and assist in analyzing properties of states and processes has been developed. A number of Excel packages that pertained to the computation of steam properties were already available in the public domain. In a companion paper1, these packages were compared and Magnus Holmgrens Xsteam functions were chosen as a starting point for the current project.

  18. Quantum-gas microscope for fermionic atoms.

    PubMed

    Cheuk, Lawrence W; Nichols, Matthew A; Okan, Melih; Gersdorf, Thomas; Ramasesh, Vinay V; Bakr, Waseem S; Lompe, Thomas; Zwierlein, Martin W

    2015-05-15

    We realize a quantum-gas microscope for fermionic ^{40}K atoms trapped in an optical lattice, which allows one to probe strongly correlated fermions at the single-atom level. We combine 3D Raman sideband cooling with high-resolution optics to simultaneously cool and image individual atoms with single-lattice-site resolution at a detection fidelity above 95%. The imaging process leaves the atoms predominantly in the 3D motional ground state of their respective lattice sites, inviting the implementation of a Maxwell's demon to assemble low-entropy many-body states. Single-site-resolved imaging of fermions enables the direct observation of magnetic order, time-resolved measurements of the spread of particle correlations, and the detection of many-fermion entanglement. PMID:26024169

  19. Quantum-Gas Microscope for Fermionic Atoms

    NASA Astrophysics Data System (ADS)

    Cheuk, Lawrence W.; Nichols, Matthew A.; Okan, Melih; Gersdorf, Thomas; Ramasesh, Vinay V.; Bakr, Waseem S.; Lompe, Thomas; Zwierlein, Martin W.

    2015-05-01

    We realize a quantum-gas microscope for fermionic 40K atoms trapped in an optical lattice, which allows one to probe strongly correlated fermions at the single-atom level. We combine 3D Raman sideband cooling with high-resolution optics to simultaneously cool and image individual atoms with single-lattice-site resolution at a detection fidelity above 95%. The imaging process leaves the atoms predominantly in the 3D motional ground state of their respective lattice sites, inviting the implementation of a Maxwell's demon to assemble low-entropy many-body states. Single-site-resolved imaging of fermions enables the direct observation of magnetic order, time-resolved measurements of the spread of particle correlations, and the detection of many-fermion entanglement.

  20. Atomic density of an harmonically trapped ideal gas near Bose-Einstein transition temperature

    E-print Network

    Rodolphe Hoppeler; Jose Viana Gomes; Denis Boiron

    2006-09-22

    We have studied the atomic density of a cloud confined in an isotropic harmonic trap at the vicinity of the Bose-Einstein transition temperature. We show that, for a non-interacting gas and near this temperature, the ground-state density has the same order of magnitude as the excited states density at the centre of the trap. This holds in a range of temperatures where the ground-state population is negligible compared to the total atom number. We compare the exact calculations, available in a harmonic trap, to semi-classical approximations. We show that these latter should include the ground-state contribution to be accurate..

  1. Ultracold Chromium: a dipolar quantum gas

    NASA Astrophysics Data System (ADS)

    Pfau, Tilman

    2006-05-01

    We report on experiments using a Bose-Einstein condensate of chromium atoms [1]. We produce up to ˜ 10^5 condensed ^52Cr atoms after forced evaporation within a crossed optical dipole trap. Due to its large magnetic moment (6?B), the dipole-dipole interaction strength in chromium is comparable with the one of the van der Waals interaction. We prove the anisotropic nature of the dipolar interaction by releasing the condensate from a cigar shaped trap [2]. This is the first experimental observation of mechanical dipolar effects in a quantum gas. We also report on the observation of 14 Feshbach resonances in elastic collisions between polarized ultra-cold ^52Cr atoms [3]. This is the first observation of collisional Feshbach resonances in an atomic species with more than one valence electron. Moreover, such resonances constitute an important tool towards the realization of a purely dipolar interacting gas as they can be used to change strength and sign of the van der Waals interaction. References 1. A. Griesmaier, J. Werner, S. Hensler, J. Stuhler, and T. Pfau, Phys. Rev. Lett. 94, 160401 (2005) 2. J. Stuhler, A. Griesmaier, T. Koch, M. Fattori, T. Pfau, S. Giovanazzi, P. Pedri, and L. Santos, Phys. Rev. Lett. 95, 150406 (2005) 3. J. Werner, A. Griesmaier, S. Hensler, J. Stuhler and T. Pfau, Phys. Rev. Lett. 94, 183201 (2005)

  2. Trapped one-dimensional ideal Fermi gas with a single impurity

    NASA Astrophysics Data System (ADS)

    Astrakharchik, G. E.; Brouzos, I.

    2013-08-01

    Ground-state properties of a single impurity in a one-dimensional Fermi gas are investigated in uniform and trapped geometries. The energy of a trapped system is obtained (i) by generalizing the McGuire expression from a uniform to trapped system (ii) within the local density approximation (iii) using the perturbative approach in the case of a weakly interacting impurity and (iv) diffusion Monte Carlo method. We demonstrate that there is a closed formula based on the exact solution of the homogeneous case which provides a precise estimation for the energy of a trapped system even for a small number of fermions and arbitrary coupling constant of the impurity. Using this expression, we analyze energy contributions from kinetic, interaction, and potential components, as well as spatial properties such as the system size and the pair-correlation function. Finally, we calculate the frequency of the breathing mode. Our analysis is directly connected and applicable to the recent experiments in microtraps.

  3. Quantum noise of non-ideal Sagnac speed meter interferometer with asymmetries

    E-print Network

    S. L. Danilishin; C. Graef; S. S. Leavey; J. Hennig; E. A. Houston; D. Pascucci; S. Steinlechner; J. Wright; S. Hild

    2015-02-19

    The speed meter concept has been identified as a technique that can potentially provide laser-interferometric measurements at a sensitivity level which surpasses the Standard Quantum Limit (SQL) over a broad frequency range. As with other sub-SQL measurement techniques, losses play a central role in speed meter interferometers and they ultimately determine the quantum noise limited sensitivity that can be achieved. So far in the literature, the quantum noise limited sensitivity has only been derived for lossless or lossy cases using certain approximations (for instance that the arm cavity round trip loss is small compared to the arm cavity mirror transmission). In this article we present a generalised, analytical treatment of losses in speed meters that allows accurate calculation of the quantum noise limited sensitivity of Sagnac speed meters with arm cavities. In addition, our analysis allows us to take into account potential imperfections in the interferometer such as an asymmetric beam splitter or differences of the reflectivities of the two arm cavity input mirrors. Finally,we use the examples of the proof-of-concept Sagnac speed meter currently under construction in Glasgow and a potential implementation of a Sagnac speed meter in the Einstein Telescope (ET) to illustrate how our findings affect Sagnac speed meters with meter- and kilometre-long baselines.

  4. Towards enhancing two-dimensional electron gas quantum confinement effects in perovskite oxide heterostructures

    NASA Astrophysics Data System (ADS)

    Yang, Kesong; Nazir, Safdar; Behtash, Maziar

    2015-03-01

    The two-dimensional electron gas (2DEG) in LaAlO3/SrTiO3 perovskite-oxide heterostructure has attracted much attention because of its potential applications in nanoelectronic devices. A 2DEG has two landmark characters: strong charge confinement in the third dimension and high electron conductivity in two dimensions. In an ideal 2DEG system, electrons can move freely along the interface but are tightly confined in the c-axis that is perpendicular to the interface. Nevertheless, the actual electron gas in the SrTiO3-based perovskite heterostructures is extended a few nanometers along the c-axis into the SrTiO3 substrate, and thus they are also called as quasi-2DEG. Actually, it is a problem of both fundamental and practical interest to achieve an ideal 2DEG via enhancing the lateral quantum confinement effects. By using first-principles electronic structure calculations, herein we proposed two possible approaches to enhance the quantum charge confinement effects by confining the electron gas within one single atomic layer in the perovskite oxide heterostructure. This work is supported by start-up funds at the University of California, San Diego.

  5. Jack Polynomials as Fractional Quantum Hall States and the Betti Numbers of the ( k + 1)-Equals Ideal

    NASA Astrophysics Data System (ADS)

    Zamaere, Christine Berkesch; Griffeth, Stephen; Sam, Steven V.

    2014-08-01

    We show that for Jack parameter ? = -( k + 1)/( r - 1), certain Jack polynomials studied by Feigin-Jimbo-Miwa-Mukhin vanish to order r when k + 1 of the coordinates coincide. This result was conjectured by Bernevig and Haldane, who proposed that these Jack polynomials are model wavefunctions for fractional quantum Hall states. Special cases of these Jack polynomials include the wavefunctions of Laughlin and Read-Rezayi. In fact, along these lines we prove several vanishing theorems known as clustering properties for Jack polynomials in the mathematical physics literature, special cases of which had previously been conjectured by Bernevig and Haldane. Motivated by the method of proof, which in the case r = 2 identifies the span of the relevant Jack polynomials with the S n -invariant part of a unitary representation of the rational Cherednik algebra, we conjecture that unitary representations of the type A Cherednik algebra have graded minimal free resolutions of Bernstein-Gelfand-Gelfand type; we prove this for the ideal of the ( k + 1)-equals arrangement in the case when the number of coordinates n is at most 2 k + 1. In general, our conjecture predicts the graded S n -equivariant Betti numbers of the ideal of the ( k + 1)-equals arrangement with no restriction on the number of ambient dimensions.

  6. Ideal-Gas Heat Capacity for 2,3,3,3-Tetrafluoropropene (HFO1234yf) Determined from Speed-of-Sound Measurements

    Microsoft Academic Search

    Yuya Kano; Yohei Kayukawa; Kenichi Fujii; Haruki Sato

    2010-01-01

    The isobaric ideal-gas heat capacity for HFO-1234yf, which is expected to be one of the best alternative refrigerants for\\u000a HFC-134a, was determined on the basis of speed-of-sound measurements in the gaseous phase. The speed of sound was measured\\u000a by means of the acoustic resonance method using a spherical cavity. The resonance frequency in the spherical cavity containing\\u000a the sample gas

  7. Exploring the Ideal Gas Law through a Quantitative Gasometric Analysis of Nitrogen Produced by the Reaction of Sodium Nitrite with Sulfamic Acid

    ERIC Educational Resources Information Center

    Yu, Anne

    2010-01-01

    The gasometric analysis of nitrogen produced in a reaction between sodium nitrite, NaNO[superscript 2], and sulfamic acid, H(NH[superscript 2])SO[superscript 3], provides an alternative to more common general chemistry experiments used to study the ideal gas law, such as the experiment in which magnesium is reacted with hydrochloric acid. This…

  8. A quantum description of the proton movement in an idealized NHN+ bridge.

    PubMed

    Lankau, Timm; Yu, Chin-Hui

    2011-07-28

    A series of model calculations was done to analyze the delocalization of the proton in the linking hydrogen bond of the (Dih)(2)H(+) cation (Dih: 4,5-dihydro-1H-imidazole). Standard quantum chemical calculations (B3LYP/D95+(d,p)) predict a low barrier hydrogen bond (LBHB) and thereby a delocalized proton in the NHN(+) hydrogen bridge. Explicit quantum calculations on the proton indicate that the delocalization of the proton does not provide enough energy to stabilize a permanent LBHB. Additional Born-Oppenheimer Molecular Dynamics (BOMD) simulations indicate further that the proton is localized at either side of the NHN(+) bridge and that a central proton position is the result of temporal averaging. The possibility of the proton to tunnel from one side to the other side of the NHN(+) bridge increases with the temperature as the trajectory of the (Dih)(2)H(+) cation runs through regions where the thermal excitation of Dih ring vibrations creates equal bonding opportunities for the proton on both sides of the bridge (vibrationally assisted proton tunneling). The quantum calculations for the proton in (Dih)(2)H(+) suggest further a broad peak for the 1 ? 0 transition with a maximum at 938 cm(-1) similar to that observed for LBHBs. Moreover, the asymmetric NHN(+) bridge in a thermally fluctuating environment is strong enough to create a significant peak at 1828 cm(-1) for the 2 ? 0 transition, while contributions from the 2 ? 1 are expected to be weak for the same reason. PMID:21691635

  9. Towards a NMR implementation of a quantum lattice gas algorithm

    Microsoft Academic Search

    Marco A. Pravia; Zhiying Chen; Jeffrey Yepez; David G. Cory

    2002-01-01

    Recent theoretical results suggest that an array of quantum information processors communicating via classical channels can be used to solve fluid dynamics problems. Quantum lattice-gas algorithms (QLGA) running on such architectures have been shown to solve the diffusion equation and the nonlinear Burgers equations. In this report, we describe progress towards an ensemble nuclear magnetic resonance (NMR) implementation of a

  10. Highly covariant quantum lattice gas model of the Dirac equation

    Microsoft Academic Search

    Jeffrey Yepez

    2011-01-01

    We revisit the quantum lattice gas model of a spinor quantum field theory-the smallest scale particle dynamics is partitioned into unitary collide and stream operations. The construction is covariant (on all scales down to a small length {\\\\ell} and small time {\\\\tau} = c {\\\\ell}) with respect to Lorentz transformations. The mass m and momentum p of the modeled Dirac

  11. Quantum lattice gas representation of some classical solitons

    Microsoft Academic Search

    George Vahala; Jeffrey Yepez; Linda Vahala

    2003-01-01

    A quantum lattice gas representation is determined for both the non-linear Schrödinger (NLS) and Korteweg–de Vries (KdV) equations. There is excellent agreement with the solutions from these representations to the exact soliton–soliton collisions of the integrable NLS and KdV equations. These algorithms could, in principle, be simulated on a hybrid quantum-classical computer.

  12. DIPPER project 871 determination of ideal-gas enthalpies of formation for key compounds, The 1991 project results

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Tasker, I.R.

    1993-09-01

    Results of a study aimed at improving group-contribution methodology for estimating thermodynamic properties of organic substances are reported. Specific weaknesses where particular group-contribution terms were unknown, or estimated because of lack of experimental data, are addressed by experimental studies of enthalpies of combustion in condensed phase, vapor-pressure measurements, and differential scanning calorimetric (d.s.c.) heat-capacity measurements. Ideal-gas enthalpies of formation of cyclohexene, phthalan (2,5-dihydrobenzo-3,4-furan), isoxazole, n-octylamine, di-n-octylamine, tri-n-octylamine, phenyl isocyanate, and 1,4,5,6-tetrahydropyrimidine are reported. Two-phase (liquid + vapor) heat capacities were determined for phthalan, isoxazole, the three octylamines, and phenyl isocyanate. Liquid-phase densities along the saturation line were measured for phthalan and isoxazole at 298 to 425 K. The critical temperature and critical density of n-octylamine were determined from d.s.c. results and critical pressure derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, pressures, and densities for cyclohexene (pressure and density only), phthalan, isoxazole, di-n-octylamine, and phenyl isocyanate. Group-additivity parameters or ring-correction terms are derived.

  13. Quantum lattice-gas model of spinor superfluids

    Microsoft Academic Search

    Jeffrey Yepez; George Vahala; Linda Vahala; Min Soe

    2010-01-01

    Spinor Bose Einstein Condensates are intriguing because of their vast range of different topological vortices. These states occur when a BEC gas is trapped in an optical lattice rather than in a magnetic well (which would result in scalar BEC vortices). A spinor BEC states also occur in a quantum gas when several hyperfine states of the atom co-exist in

  14. Self-energy of an impurity in an ideal Fermi gas to second order in the interaction strength

    NASA Astrophysics Data System (ADS)

    Trefzger, Christian; Castin, Yvan

    2014-09-01

    We study in three dimensions the problem of a spatially homogeneous zero-temperature ideal Fermi gas of spin-polarized particles of mass m perturbed by the presence of a single distinguishable impurity of mass M. The interaction between the impurity and the fermions involves only the partial s wave through the scattering length a and has negligible range b compared to the inverse Fermi wave number 1/kF of the gas. Through the interactions with the Fermi gas the impurity gives birth to a quasiparticle, which will be here a Fermi polaron (or more precisely a monomeron). We consider the general case of an impurity moving with wave vector K ?0: Then the quasiparticle acquires a finite lifetime in its initial momentum channel because it can radiate particle-hole pairs in the Fermi sea. A description of the system using a variational approach, based on a finite number of particle-hole excitations of the Fermi sea, then becomes inappropriate around K =0. We rely thus upon perturbation theory, where the small and negative parameter kFa?0- excludes any branches other than the monomeronic one in the ground state (as, e.g., the dimeronic one), and allows us a systematic study of the system. We calculate the impurity self-energy ?(2)(K,?) up to second order included in a. Remarkably, we obtain an analytical explicit expression for ?(2)(K,?), allowing us to study its derivatives in the plane (K,?). These present interesting singularities, which in general appear in the third-order derivatives ?3?(2)(K,?). In the special case of equal masses, M =m, singularities appear already in the physically more accessible second-order derivatives ?2?(2)(K,?); using a self-consistent heuristic approach based on ?(2) we then regularize the divergence of the second-order derivative ?K2?E(K) of the complex energy of the quasiparticle found in Trefzger and Castin [Europhys. Lett. 104, 50005 (2013), 10.1209/0295-5075/104/50005] at K =kF, and we predict an interesting scaling law in the neighborhood of K =kF. As a by product of our theory we have access to all moments of the momentum of the particle-hole pair emitted by the impurity while damping its motion in the Fermi sea at the level of Fermi's golden rule.

  15. Similarity solution for the flow behind a shock wave in a non-ideal gas with heat conduction and radiation heat-flux in magnetogasdynamics

    NASA Astrophysics Data System (ADS)

    Nath, G.; Vishwakarma, J. P.

    2014-05-01

    The propagation of a spherical (or cylindrical) shock wave in a non-ideal gas with heat conduction and radiation heat-flux, in the presence of a spacially decreasing azimuthal magnetic field, driven out by a moving piston is investigated. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be of the diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient ?R are assumed to vary with temperature and density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. The shock wave moves with variable velocity and the total energy of the wave is non-constant. Similarity solutions are obtained for the flow-field behind the shock and the effects of variation of the heat transfer parameters, the parameter of the non-idealness of the gas, both, decreases the compressibility of the gas and hence there is a decrease in the shock strength. Further, it is investigated that with an increase in the parameters of radiative and conductive heat transfer the tendency of formation of maxima in the distributions of heat flux, density and isothermal speed of sound decreases. The pressure and density vanish at the inner surface (piston) and hence a vacuum is form at the center of symmetry. The shock waves in conducting non-ideal gas with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of central part of star burst galaxies, nuclear explosion, chemical detonation, rupture of a pressurized vessels, in the analysis of data from exploding wire experiments, and cylindrically symmetric hypersonic flow problems associated with meteors or reentry vehicles, etc. The findings of the present works provided a clear picture of whether and how the non-idealness parameter, conductive and radiative heat transfer parameters and the magnetic field affect the flow behind the shock front.

  16. Simulating an Interacting Quantum Gas with Superconducting Circuits

    NASA Astrophysics Data System (ADS)

    Eichler, Christopher; Mlynek, Jonas; Butscher, Jonas; Kurpiers, Philipp; Osborne, Tobias; Wallraff, Andreas

    2015-03-01

    The high level of control achievable over quantized degrees of freedom have turned superconducting circuits into one of the prime physical architectures for quantum computing and simulation. While conventional approaches towards quantum information processing mostly rely on unitary time evolution, more recently open-system dynamics are considered for quantum simulations. In this talk, I will present experiments in which we use an open cavity QED system with tunable interactions to simulate the ground state of an interacting Bose gas confined in one dimension. These experiments rely on the ability to efficiently measure higher order photon correlations of the cavity output field. For this purpose we have developed a quantum limited amplifier achieving phase-preserving amplification at large bandwidth and high dynamic range. Our results explore a different path towards the simulation of complex quantum many-body physics based on the controlled generation and detection of nonclassical radiation in an open quantum system.

  17. Gas of wormholes in Euclidean quantum field theory

    E-print Network

    E. P. Savelova

    2012-11-28

    We model the spacetime foam picture by a gas of wormholes in Euclidean field theory. It is shown that at large distances the presence of such a gas leads merely to a renormalization of mass and charge values. We also demonstrate that there exist a class of specific distributions of point-like wormholes which essentially change the ultraviolet behavior of Green functions and lead to finite quantum field theories.

  18. Quantum lattice gas algorithm for quantum turbulence and vortex reconnection in the Gross-Pitaevskii equation

    Microsoft Academic Search

    George Vahala; Jeffrey Yepez; Linda Vahala

    2008-01-01

    The ground state wave function for a Bose Einstein condensate is well described by the Gross-Pitaevskii equation. A Type-II quantum algorithm is devised that is ideally parallelized even on a classical computer. Only 2 qubits are required per spatial node. With unitary local collisions, streaming of entangled states and a spatially inhomogeneous unitary gauge rotation one recovers the Gross-Pitaevskii equation.

  19. Two-dimensional quantum gas in a hybrid surface trap

    NASA Astrophysics Data System (ADS)

    Gillen, J. I.; Bakr, W. S.; Peng, A.; Unterwaditzer, P.; Fölling, S.; Greiner, M.

    2009-08-01

    We demonstrate the realization of a two-dimensional (2D) quantum gas in a smooth optical surface trap. Using a combination of evanescent wave, standing wave, and magnetic potentials, we create a long-lived quantum gas deep in the 2D regime at a distance of a few microns from a glass surface. To realize a system suitable for many-body quantum simulation, we introduce methods such as broadband “white” light to create evanescent and standing waves to realize a smooth potential with a trap frequency aspect ratio of 300:1:1. We are able to detect phase fluctuations and vortices, and we demonstrate cooling to degeneracy and low disorder in the 2D configuration.

  20. Quantum Theory of a Gas Laser. II

    Microsoft Academic Search

    Charles R. Willis

    1968-01-01

    We generalize the method of deriving a kinetic equation for a gas laser developed in the first paper of this series to include radiation-matter correlations. As a consequence, we are able to show that the first Born approximation with asymptotic conditions which contain radiation-matter correlations is sufficient to explain the nonthermal photon distribution observed in photon-counting experiments. Our derivation includes

  1. Finite-Difference Solution for Laminar or Turbulent Boundary Layer Flow over Axisymmetric Bodies with Ideal Gas, CF4, or Equilibrium Air Chemistry

    NASA Technical Reports Server (NTRS)

    Hamilton, H. Harris, II; Millman, Daniel R.; Greendyke, Robert B.

    1992-01-01

    A computer code was developed that uses an implicit finite-difference technique to solve nonsimilar, axisymmetric boundary layer equations for both laminar and turbulent flow. The code can treat ideal gases, air in chemical equilibrium, and carbon tetrafluoride (CF4), which is a useful gas for hypersonic blunt-body simulations. This is the only known boundary layer code that can treat CF4. Comparisons with experimental data have demonstrated that accurate solutions are obtained. The method should prove useful as an analysis tool for comparing calculations with wind tunnel experiments and for making calculations about flight vehicles where equilibrium air chemistry assumptions are valid.

  2. Manipulation of Ideals 1 Radical ideals

    E-print Network

    Verschelde, Jan

    Manipulation of Ideals 1 Radical ideals the radical ideal membership problem 2 Independence Computation (MCS 563) Manipulation of Ideals L-33 7 April 2014 1 / 30 #12;Manipulation of Ideals 1 Radical ideals the radical ideal membership problem 2 Independence Varieties a problem in algebraic statistics 3

  3. Dual-wavelength quantum cascade laser for trace gas spectroscopy

    SciTech Connect

    Jágerská, J.; Tuzson, B.; Mangold, M.; Emmenegger, L. [Laboratory for Air Pollution and Environmental Technology, Empa, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Jouy, P.; Hugi, A.; Beck, M.; Faist, J. [Institute for Quantum Electronics, ETH Zürich, Wolfgang-Pauli-Str. 16, 8093 Zürich (Switzerland); Looser, H. [Institute for Aerosol and Sensor Technology, FHNW, Klosterzelgstrasse 2, 5210 Windisch (Switzerland)

    2014-10-20

    We demonstrate a sequentially operating dual-wavelength quantum cascade laser with electrically separated laser sections, emitting single-mode at 5.25 and 6.25??m. Based on a single waveguide ridge, this laser represents a considerable asset to optical sensing and trace gas spectroscopy, as it allows probing multiple gas species with spectrally distant absorption features using conventional optical setups without any beam combining optics. The laser capability was demonstrated in simultaneous NO and NO{sub 2} detection, reaching sub-ppb detection limits and selectivity comparable to conventional high-end spectroscopic systems.

  4. The spin Hall effect in a quantum gas.

    PubMed

    Beeler, M C; Williams, R A; Jiménez-García, K; LeBlanc, L J; Perry, A R; Spielman, I B

    2013-06-13

    Electronic properties such as current flow are generally independent of the electron's spin angular momentum, an internal degree of freedom possessed by quantum particles. The spin Hall effect, first proposed 40 years ago, is an unusual class of phenomena in which flowing particles experience orthogonally directed, spin-dependent forces--analogous to the conventional Lorentz force that gives the Hall effect, but opposite in sign for two spin states. Spin Hall effects have been observed for electrons flowing in spin-orbit-coupled materials such as GaAs and InGaAs (refs 2, 3) and for laser light traversing dielectric junctions. Here we observe the spin Hall effect in a quantum-degenerate Bose gas, and use the resulting spin-dependent Lorentz forces to realize a cold-atom spin transistor. By engineering a spatially inhomogeneous spin-orbit coupling field for our quantum gas, we explicitly introduce and measure the requisite spin-dependent Lorentz forces, finding them to be in excellent agreement with our calculations. This 'atomtronic' transistor behaves as a type of velocity-insensitive adiabatic spin selector, with potential application in devices such as magnetic or inertial sensors. In addition, such techniques for creating and measuring the spin Hall effect are clear prerequisites for engineering topological insulators and detecting their associated quantized spin Hall effects in quantum gases. As implemented, our system realizes a laser-actuated analogue to the archetypal semiconductor spintronic device, the Datta-Das spin transistor. PMID:23739329

  5. Rigorous investigation of the reduced density matrix for the ideal Bose gas in harmonic traps by a loop-gas-like

    E-print Network

    Paris-Sud XI, Université de

    -gas-like approach provides relevant information which can help guide numerical investigations on highly anisotropic Introduction. 2 1.1 Bose-Einstein condensation (BEC) in dilute cold alkali atoms gases. . . . . . . . . 2 1.3.4 The local properties (Part 2)­Localization of the condensate/thermal gas. . 14 2.3.5 Meaning of Theorems 2

  6. Rigorous investigation of the reduced density matrix for the ideal Bose gas in harmonic traps by a loop-gas-like

    E-print Network

    -gas-like approach provides relevant information which can help guide numerical investigations on highly anisotropic Introduction. 2 1.1 Bose-Einstein condensation (BEC) in dilute cold alkali atoms gases. . . . . . . . . 2 1.3.4 The local properties (Part 2)­Localization of the condensate/thermal gas. . 14 2.3.5 Meaning of Theorem 2

  7. Ultrastable, Zerodur-based optical benches for quantum gas experiments.

    PubMed

    Duncker, Hannes; Hellmig, Ortwin; Wenzlawski, André; Grote, Alexander; Rafipoor, Amir Jones; Rafipoor, Mona; Sengstock, Klaus; Windpassinger, Patrick

    2014-07-10

    Operating ultracold quantum gas experiments outside of a laboratory environment has so far been a challenging goal, largely due to the lack of sufficiently stable optical systems. In order to increase the thermal stability of free-space laser systems, the application of nonstandard materials such as glass ceramics is required. Here, we report on Zerodur-based optical systems which include single-mode fiber couplers consisting of multiple components jointed by light-curing adhesives. The thermal stability is thoroughly investigated, revealing excellent fiber-coupling efficiencies between 0.85 and 0.92 in the temperature range from 17°C to 36°C. In conjunction with successfully performed vibration tests, these findings qualify our highly compact systems for atom interferometry experiments aboard a sounding rocket as well as various other quantum information and sensing applications. PMID:25090066

  8. Sex Education and Ideals

    ERIC Educational Resources Information Center

    de Ruyter, Doret J.; Spiecker, Ben

    2008-01-01

    This article argues that sex education should include sexual ideals. Sexual ideals are divided into sexual ideals in the strict sense and sexual ideals in the broad sense. It is argued that ideals that refer to the context that is deemed to be most ideal for the gratification of sexual ideals in the strict sense are rightfully called sexual…

  9. Universal quantum viscosity in a unitary Fermi gas.

    PubMed

    Cao, C; Elliott, E; Joseph, J; Wu, H; Petricka, J; Schäfer, T; Thomas, J E

    2011-01-01

    A Fermi gas of atoms with resonant interactions is predicted to obey universal hydrodynamics, in which the shear viscosity and other transport coefficients are universal functions of the density and temperature. At low temperatures, the viscosity has a universal quantum scale ? n, where n is the density and ? is Planck's constant h divided by 2?, whereas at high temperatures the natural scale is p(T)(3)/?(2), where p(T) is the thermal momentum. We used breathing mode damping to measure the shear viscosity at low temperature. At high temperature T, we used anisotropic expansion of the cloud to find the viscosity, which exhibits precise T(3/2) scaling. In both experiments, universal hydrodynamic equations including friction and heating were used to extract the viscosity. We estimate the ratio of the shear viscosity to the entropy density and compare it with that of a perfect fluid. PMID:21148347

  10. Highly covariant quantum lattice gas model of the Dirac equation

    E-print Network

    Jeffrey Yepez

    2011-06-03

    We revisit the quantum lattice gas model of a spinor quantum field theory-the smallest scale particle dynamics is partitioned into unitary collide and stream operations. The construction is covariant (on all scales down to a small length {\\ell} and small time {\\tau} = c {\\ell}) with respect to Lorentz transformations. The mass m and momentum p of the modeled Dirac particle depend on {\\ell} according to newfound relations m = mo cos (2{\\pi}{\\ell}/{\\lambda}) and p = (h/2{\\pi}{\\ell}) sin(2{\\pi}{\\ell}/{\\lambda}), respectively, where {\\lambda} is the Compton wavelength of the modeled particle. These relations represent departures from a relativistically invariant mass and the de Broglie relation-when taken as quantifying numerical errors the model is physically accurate when {\\ell} {\\ll} {\\lambda}. Calculating the vacuum energy in the special case of a massless spinor field, we find that it vanishes (or can have a small positive value) for a sufficiently large wave number cutoff. This is a marked departure from the usual behavior of such a massless field.

  11. Highly covariant quantum lattice gas model of the Dirac equation

    E-print Network

    Yepez, Jeffrey

    2011-01-01

    We revisit the quantum lattice gas model of a spinor quantum field theory-the smallest scale particle dynamics is partitioned into unitary collide and stream operations. The construction is covariant (on all scales down to a small length {\\ell} and small time {\\tau} = c {\\ell}) with respect to Lorentz transformations. The mass m and momentum p of the modeled Dirac particle depend on {\\ell} according to newfound relations m = mo cos (2{\\pi}{\\ell}/{\\lambda}) and p = (h/2{\\pi}{\\ell}) sin(2{\\pi}{\\ell}/{\\lambda}), respectively, where {\\lambda} is the Compton wavelength of the modeled particle. These relations represent departures from a relativistically invariant mass and the de Broglie relation-when taken as quantifying numerical errors the model is physically accurate when {\\ell} {\\ll} {\\lambda}. Calculating the vacuum energy in the special case of a massless spinor field, we find that it vanishes (or can have a small positive value) for a sufficiently large wave number cutoff. This is a marked departure from th...

  12. Quantum holographic encoding in a two-dimensional electron gas

    SciTech Connect

    Moon, Christopher

    2010-05-26

    The advent of bottom-up atomic manipulation heralded a new horizon for attainable information density, as it allowed a bit of information to be represented by a single atom. The discrete spacing between atoms in condensed matter has thus set a rigid limit on the maximum possible information density. While modern technologies are still far from this scale, all theoretical downscaling of devices terminates at this spatial limit. Here, however, we break this barrier with electronic quantum encoding scaled to subatomic densities. We use atomic manipulation to first construct open nanostructures - 'molecular holograms' - which in turn concentrate information into a medium free of lattice constraints: the quantum states of a two-dimensional degenerate Fermi gas of electrons. The information embedded in the holograms is transcoded at even smaller length scales into an atomically uniform area of a copper surface, where it is densely projected into both two spatial degrees of freedom and a third holographic dimension mapped to energy. In analogy to optical volume holography, this requires precise amplitude and phase engineering of electron wavefunctions to assemble pages of information volumetrically. This data is read out by mapping the energy-resolved electron density of states with a scanning tunnelling microscope. As the projection and readout are both extremely near-field, and because we use native quantum states rather than an external beam, we are not limited by lensing or collimation and can create electronically projected objects with features as small as {approx}0.3 nm. These techniques reach unprecedented densities exceeding 20 bits/nm{sup 2} and place tens of bits into a single fermionic state.

  13. Universal Quantum Viscosity in a Unitary Fermi Gas

    NASA Astrophysics Data System (ADS)

    Cao, Chenglin

    Unitary Fermi gases, first observed in 2002, have been widely studied as they provide model systems for tabletop research on a variety of strongly coupled systems, including the high temperature superconductors, quark-gluon plasmas and neutron stars. A two component 6Li unitary Fermi gas is created through a collisional Feshbach resonance centered around 834G, using all-optical trapping and cooling methods. In the vicinity of the Feshbach resonance, the atoms are strongly interacting and exhibit universal behaviors, where the equilibrium thermodynamic properties and transport coefficients are universal functions of the density n and temperature T. Thus, unitary Fermi gases provide a paradigm to study nonperturbative many-body physics, which is of fundamental significance and field-crossing interests. This dissertation reports the measurement of the quantum shear viscosity in a 6Li unitary Fermi gas, which is the first measurement of transport coefficients for unitary Fermi gases. Two hydrodynamic experiments are employed to measure the shear viscosity eta in different temperature regimes: the anisotropic expansion for the high temperature regime and the radial breathing mode for the low temperature regime. In order to consistently and quantitatively extract the shear viscosity from these two experiments, the hydrodynamic theory is utilized to derive the universal hydrodynamic equations, which include both friction force and heating arising from frictions. These equations are simplified and solved, considering the universal properties of unitary Fermi gases as well as the specific conditions for each experiment. Using these universal hydrodynamic equations, shear viscosity is extracted from the anisotropic expansion conducted at high temperatures and the predicted eta ? T3/2 scaling is demonstrated. The demonstration of the high temperature scaling sets a benchmark for measuring viscosity at low temperatures. For the low temperature breathing mode experiment, the shear viscosity is directly related to the damping rate of an oscillating cloud, through the same universal hydrodynamic equations. The raw data from the previously measured radial breathing experiments are carefully analyzed to extract the shear viscosity. The low temperature data join with the high temperature data smoothly, which presents the full measurement of the quantum shear viscosity from nearly the ground state to the two-body Boltzmann regime. The possible effects of the bulk viscosity in the high temperature anisotropic expansion experiment is also studied and found to be consistent with the predicted vanishing bulk viscosity in the normal fluid phase at unitarity. Using the measured shear viscosity eta and the previously measured entropy density s, the ratio of eta/s is estimated and therefore compared to a string theory limit, which conjectures eta/ s ? h/4pikB for any fluid and defines a perfect fluid when the equality is satisfied. It is found that eta/s, for a unitary Fermi gas at the normal-superfluid transition point, is about 5 times the string limit. This shows that our unitary Fermi gas exhibit nearly perfect fluidity at low temperatures. In addition to the quantum shear viscosity measurement, consistent and accurate methods of calibrating the energy and temperature for unitary Fermi gases is also developed in this thesis. While the energy is calculated from the cloud dimensions by exploiting the virial theorem, the temperature is determined using different methods for different temperature regimes. At high temperatures, the second virial coefficient approximation is applied to the energy density, from which a variety of thermodynamic quantities, including the temperature, are derived. For the low temperatures, the previous calibration from the energy E and entropy S measurement is improved by using a better calculation on the entropy and adding more constraints at higher temperatures using the second virial approximation. A power law curve with discontinues heat capacity is then fitted to the E-S curve and the temperature is obtained us

  14. Thermodynamics of Quantum Ultra-cold Neutron Gas under Gravity of The Earth

    E-print Network

    Hiromi Kaneko; Akihiro Tohsaki; Atsushi Hosaka

    2012-06-29

    The stored ultra-cold neutrons have been developed. A high density ultra-cold neutron gas has been recently produced by using the nuclear spallation method. We investigate the thermodynamic properties of the quantum ultra-cold neutron gas in the Earth's gravitational field. We find that the quantum effects increase temperature dependence of the chemical potential and the internal energy in the low temperature region. The density distribution of quantum ultra-cold neutron gas is modified by the Earth's gravitational field.

  15. The influence of quantum degeneracy and irreversibility on the performance of a Fermi quantum refrigeration cycle

    Microsoft Academic Search

    Yue Zhang; Bihong Lin; Jincan Chen

    2004-01-01

    An irreversible cycle model of the quantum refrigeration cycle using an ideal Fermi gas as the working substance is established. The cycle consists of two adiabatic and two isobaric processes and consequently may be simply referred to as the Fermi Brayton refrigeration cycle. The performance of the cycle is investigated, based on the equation of state of an ideal Fermi

  16. Quantum lattice-gas model for the Burgers equation

    Microsoft Academic Search

    Jeffrey Yepez

    2000-01-01

    A quantum algorithm is presented for modeling the time evolution of a continuous field governed by the nonlinear Burgers equation in one spa- tial dimension. It is a microscopic-scale algorithm for a type-II quantum computer, a large lattice of small quantum computers interconnected in nearest neighbor fashion by classical communication channels. A formula for quantum state preparation is presented. The

  17. Buoyancy-Driven Heat Transfer During Application of a Thermal Gradient for the Study of Vapor Deposition at Low Pressure Using and Ideal Gas

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Hung, R. J.; Paley, M. S.; Penn, B. G.; Long, Y. T.

    1996-01-01

    A mathematical model has been developed to determine heat transfer during vapor deposition of source materials under a variety of orientations relative to gravitational accelerations. The model demonstrates that convection can occur at total pressures as low as 10-2 mm Hg. Through numerical computation, using physical material parameters of air, a series of time steps demonstrates the development of flow and temperature profiles during the course of vapor deposition. These computations show that in unit gravity vapor deposition occurs by transport through a fairly complicated circulating flow pattern when applying heat to the bottom of the vessel with parallel orientation with respect to the gravity vector. The model material parameters for air predict the effect of kinematic viscosity to be of the same order as thermal diffusivity, which is the case for Prandtl number approx. 1 fluids. Qualitative agreement between experiment and the model indicates that 6-(2-methyl-4-nitroanilino)-2,4-hexadiyn-l-ol (DAMNA) at these pressures indeed approximates an ideal gas at the experiment temperatures, and may validate the use of air physical constants. It is apparent that complicated nonuniform temperature distribution in the vapor could dramatically affect the homogeneity, orientation, and quality of deposited films. The experimental test i's a qualitative comparison of film thickness using ultraviolet-visible spectroscopy on films generated in appropriately oriented vapor deposition cells. In the case where heating of the reaction vessel occurs from the top, deposition of vapor does not normally occur by convection due to a stable stratified medium. When vapor deposition occurs in vessels heated at the bottom, but oriented relative to the gravity vector between these two extremes, horizontal thermal gradients induce a complex flow pattern. In the plane parallel to the tilt axis, the flow pattern is symmetrical and opposite in direction from that where the vessel is positioned vertically. The ground-based experiments are sufficient preliminary tests of theory and should be of significant interest regarding vapor deposited films in microgravity.

  18. Experimental demonstration and exploration of quantum lattice gas algorithms

    E-print Network

    Chen, Zhiying, Ph. D. Massachusetts Institute of Technology

    2005-01-01

    Recently, it has been suggested that an array of small quantum information processors sharing classical information can be used to solve selected computational problems, referred to as a type-II quantum computer. The first ...

  19. Exploration the quantum and transport lifetimes of electron gas in partially alloyed AlGaAs quantum well

    NASA Astrophysics Data System (ADS)

    Rahmani, Amir; Sadeghzadeh, Mohammad Ali; Khordad, Reza

    2015-07-01

    Low temperature transport and quantum lifetimes (?T,?Q) of two dimensional electron gas (2DEG) confined in the partially alloyed AlxGa1-xAs (with 0 < x < 0.01) quantum well have been explored. Scattering angle ? , 2DEG density ns , and alloy content x dependence of electron lifetimes due to screened short range (alloy disorder) and long range Coulomb interaction (remote and background charged impurities) scattering mechanisms have been evaluated. We explain how different components limit the total transport and quantum electron lifetimes. Finally, the theoretical lifetimes versus alloy content x has been exemplified with experimental results.

  20. Quantum lattice gas model of Fermi systems with relativistic energy relations

    E-print Network

    Jeffrey Yepez

    2013-07-12

    Presented are several example quantum computing representations of quantum systems with a relativistic energy relation. Basic unitary representations of free Dirac particles and BCS superconductivity are given. Then, these are combined into a novel unitary representation of a Fermi condensate superfluid. The modeling approach employs an operator splitting method that is an analytically closed-form product decomposition of the unitary evolution operator, applied in the high-energy limit. This allows the relativistic wave equations to be cast as unitary finite-difference equations. The split evolution operators (comprising separate kinetic and interaction energy evolution terms) serve as quantum lattice gas models useful for efficient quantum simulation.

  1. Master Equation for a Quantum Particle in a Gas

    SciTech Connect

    Hornberger, Klaus [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, 80333 Munich (Germany)

    2006-08-11

    The equation for the quantum motion of a Brownian particle in a gaseous environment is derived by means of S-matrix theory. This quantum version of the linear Boltzmann equation accounts nonperturbatively for the quantum effects of the scattering dynamics and describes decoherence and dissipation in a unified framework. As a completely positive master equation it incorporates both the known equation for an infinitely massive Brownian particle and the classical linear Boltzmann equation as limiting cases.

  2. Quantum Lattice Gas Algorithms for MHD and Solitons

    Microsoft Academic Search

    George Vahala; Linda Vahala; Jeffrey Yepez

    2003-01-01

    While classical computers work on bits '0' and '1', quantum computers can form superposition of the qubits | 0 > and | 1 >. In geometric terms, the classical computer's operational space consists of two points, while that of the quantum computer is the Bloch sphere - the surface manifold of a unit sphere. It is this greater geometric freedom

  3. Modeling an adiabatic quantum computer via an exact map to a gas of particles.

    PubMed

    Zagoskin, A M; Savel'ev, S; Nori, Franco

    2007-03-23

    We map adiabatic quantum evolution on the classical Hamiltonian dynamics of a 1D gas (Pechukas gas) and simulate the latter numerically. This approach turns out to be both insightful and numerically efficient, as seen from our example of a CNOT gate simulation. For a general class of Hamiltonians we show that the escape probability from the initial state scales no faster than |lambda|gamma, where |lambda| is the adiabaticity parameter. The scaling exponent for the escape probability is gamma=1/2 for all levels, except the edge (bottom and top) ones, where gamma approximately < 1/3. In principle, our method can solve arbitrarily large adiabatic quantum Hamiltonians. PMID:17501105

  4. PET 424304 2013 Exercises 1+2 of 4 12 Feb + 14 Feb 2013 1. ideal gas: s = s2-s1 = cpln(T2/T1) -R ln(p2/p1) (T << Tcrit; p << pcrit)

    E-print Network

    Zevenhoven, Ron

    PET 424304 2013 Exercises 1+2 of 4 12 Feb + 14 Feb 2013 1. ideal gas: s = s2- s1 = cp·ln(T2/T1) - R· ln(p2/p1) (T 1 (20 1 bar, h2 h1) = 1 kg/s / 0,032 kg/mol = 31,25 mol/s s = - R· ln(1/20) = 24,9 J/(molK) x = ·T°· s = 31,25·293·24,9 = 228,1 kW 2. 1 kg Al

  5. Dynamics of a driven quantum gas: Non-hermiticity, pseudo-spectra and phase transitions

    NASA Astrophysics Data System (ADS)

    Makris, Konstantinos; Kulkarni, Manas; Tureci, Hakan

    2015-03-01

    System of an optically driven quantum gas coupled to a single mode of a leaky cavity offers a unique platform to study open quantum systems. This system displays two exceptional points and a quantum critical point when the drive strength (equivalently, the light-matter coupling) is tuned. Here, we study the non-normal properties of this system especially near these special points. Adapting the rich mathematics behind the theory of pseudo-spectra, we characterize the open quantum phase transitions in this system by studying the fluctuations. Our method offers a novel way to understand physics near criticality beyond the traditional approach of arriving at a phase diagram using the semi-classical solutions arising from a mean field approach. We further show that the quench dynamics of a driven dissipative quantum gas displays a non-Markovian dynamics featuring substantial transient amplification of the photon flux near the critical point. We also investigate the non-Hermitian physics behind two-operator products thereby shining light on higher order quantum correlations in an open quantum system.

  6. Chemical Potential Jump during Evaporation of a Quantum Bose Gas

    E-print Network

    E. A. Bedrikova; A. V. Latyshev

    2013-01-07

    The dependence of the chemical potential jump coefficient on the evaporation coefficient is analyzed for the case in which the evaporating component is a Bose gas. The concentration of the evaporating component is assumed to be much lower than the concentration of the carrier gas. The expression for the chemical potential jump is derived from the analytic solution of the problem for the case in which the collision frequency of molecules of the evaporating component is constant.

  7. Engineering Light: Quantum Cascade Lasers

    SciTech Connect

    Claire Gmachl

    2010-03-17

    Quantum cascade lasers are ideal for environmental sensing and medical diagnostic applications. Gmachl discusses how these lasers work, and their applications, including their use as chemical trace gas sensors. As examples of these applications, she briefly presents results from her field campaign at the Beijing Olympics, and ongoing campaigns in Texas, Maryland, and Ghana.

  8. Multi-frequency Superconducting Cavity Stabilized Oscillators (SCSO) for Quantum-Gas

    E-print Network

    Yeh, Nai-Chang

    Multi-frequency Superconducting Cavity Stabilized Oscillators (SCSO) for Quantum-Gas Measurements of Technology, Pasadena, CA 91109, USA We report on the development of a superconducting cavity stabilized oscil- lator (SCSO) for use as a high-stability frequency source and for precision measurements. The SCSO

  9. Cyclotron resonance photoconductivity of a two-dimensional electron gas in HgTe quantum wells

    E-print Network

    Ganichev, Sergey

    -dimensional electron gas (2DEG). From the resonance magnetic field strength effective masses and their dependenceH) oscillations used so far in this material our measurements demon- strate that the CRP provides a more accurate, heterostructure, HgTe quantum wells. * Corresponding author. Institute of Semiconductor Physics, pr. Lavrentjeva

  10. A quantum gas microscope for detecting single atoms in a Hubbard-regime optical lattice.

    PubMed

    Bakr, Waseem S; Gillen, Jonathon I; Peng, Amy; Fölling, Simon; Greiner, Markus

    2009-11-01

    Recent years have seen tremendous progress in creating complex atomic many-body quantum systems. One approach is to use macroscopic, effectively thermodynamic ensembles of ultracold atoms to create quantum gases and strongly correlated states of matter, and to analyse the bulk properties of the ensemble. For example, bosonic and fermionic atoms in a Hubbard-regime optical lattice can be used for quantum simulations of solid-state models. The opposite approach is to build up microscopic quantum systems atom-by-atom, with complete control over all degrees of freedom. The atoms or ions act as qubits and allow the realization of quantum gates, with the goal of creating highly controllable quantum information systems. Until now, the macroscopic and microscopic strategies have been fairly disconnected. Here we present a quantum gas 'microscope' that bridges the two approaches, realizing a system in which atoms of a macroscopic ensemble are detected individually and a complete set of degrees of freedom for each of them is determined through preparation and measurement. By implementing a high-resolution optical imaging system, single atoms are detected with near-unity fidelity on individual sites of a Hubbard-regime optical lattice. The lattice itself is generated by projecting a holographic mask through the imaging system. It has an arbitrary geometry, chosen to support both strong tunnel coupling between lattice sites and strong on-site confinement. Our approach can be used to directly detect strongly correlated states of matter; in the context of condensed matter simulation, this corresponds to the detection of individual electrons in the simulated crystal. Also, the quantum gas microscope may enable addressing and read-out of large-scale quantum information systems based on ultracold atoms. PMID:19890326

  11. Creation of a low-entropy quantum gas of polar molecules in an optical lattice

    E-print Network

    Moses, Steven A; Miecnikowski, Matthew T; Yan, Bo; Gadway, Bryce; Ye, Jun; Jin, Deborah S

    2015-01-01

    Ultracold polar molecules, with their long-range electric dipolar interactions, offer a unique platform for studying correlated quantum many-body phenomena such as quantum magnetism. However, realizing a highly degenerate quantum gas of molecules with a low entropy per particle has been an outstanding experimental challenge. In this paper, we report the synthesis of a low entropy molecular quantum gas by creating molecules at individual sites of a three-dimensional optical lattice that is initially loaded from a low entropy mixture of K and Rb quantum gases. We make use of the quantum statistics and interactions of the initial atom gases to load into the optical lattice, simultaneously and with good spatial overlap, a Mott insulator of bosonic Rb atoms and a single-band insulator of fermionic K atoms. Then, using magneto-association and optical state transfer, we efficiently produce ground-state molecules in the lattice at those sites that contained one Rb and one K atom. The achieved filling fraction of 25% ...

  12. Moderately dense gas quantum kinetic theory: Aspects of pair correlations R. F. Snider and G. W. Wei

    E-print Network

    Wei, Guo-Wei

    their decay via interactions with other particles in the gas. The molecular description is given of such a gasModerately dense gas quantum kinetic theory: Aspects of pair correlations R. F. Snider and G. W. Wei Department of Chemistry, University of British Columbia, Vancouver V6T 1Z1, Canada J. G. Muga

  13. Quantum phases of a one-dimensional dipolar Fermi gas

    NASA Astrophysics Data System (ADS)

    Mosadeq, Hamid; Asgari, Reza

    2015-02-01

    We quantitatively obtain the quantum ground-state phases of a Fermi system with on-site and dipole-dipole interactions in one-dimensional lattice chains within the density matrix renormalization group. We show, at a given spin polarization, the existence of six phases in the phase diagram and find that the phases are highly dependent on the spin degree of freedom. These phases can be constructed using available experimental techniques.

  14. Underbarrier nucleation kinetics in a metastable quantum liquid near the liquid-gas spinodal line

    SciTech Connect

    Burmistrov, S.N. [Kurchatov Institute, 123182, Moscow, Russia (Russian Federation); Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro, Tokyo 152-8551 (Japan); Dubovskii, L.B. [Kurchatov Institute, 123182, Moscow (Russian Federation); Okuda, Y. [Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro, Tokyo 152-8551 (Japan)

    2005-02-01

    We develop a theory that incorporates the relaxation properties of a condensed medium into the quantum decay of a metastable liquid near the liquid-gas spinodal line at low temperatures. We find that both the regime and the rate of quantum nucleation strongly depend on the relaxation time and its temperature behavior. The quantum nucleation rate slows down with decreasing relaxation time. We also discuss the low-temperature experiments on cavitation in normal {sup 3}He and superfluid {sup 4}He at negative pressures. It is the drastic distinctions in the properties of the high-frequency sound mode and in the temperature behavior of the relaxation time that make the quantum cavitation kinetics in {sup 3}He and {sup 4}He completely different.

  15. Creating a quantum degenerate gas of stable molecules via weak photoassociation

    NASA Astrophysics Data System (ADS)

    Mackie, Matt; Phou, Pierre

    2010-07-01

    Quantum degenerate molecules represent a new paradigm for fundamental studies and practical applications. Association of already quantum degenerate atoms into molecules provides a crucial shortcut around the difficulty of cooling molecules to ultracold temperatures. Whereas association can be induced with either laser or magnetic fields, photoassociation requires impractical laser intensity to overcome poor overlap between the atom pair and molecular wave functions, and experiments are currently restricted to magnetoassociation. Here we model realistic production of a quantum degenerate gas of stable molecules via two-photon photoassociation of Bose-condensed atoms. An adiabatic change of the laser frequency converts the initial atomic condensate almost entirely into stable molecular condensate, even for low-intensity lasers. Results for dipolar LiNa provide an upper bound on the necessary photoassociation laser intensity for alkali-metal atoms ~30 W/cm2, indicating a feasible path to quantum degenerate molecules beyond magnetoassociation.

  16. Creating a quantum degenerate gas of stable molecules via weak photoassociation

    SciTech Connect

    Mackie, Matt; Phou, Pierre [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)

    2010-07-15

    Quantum degenerate molecules represent a new paradigm for fundamental studies and practical applications. Association of already quantum degenerate atoms into molecules provides a crucial shortcut around the difficulty of cooling molecules to ultracold temperatures. Whereas association can be induced with either laser or magnetic fields, photoassociation requires impractical laser intensity to overcome poor overlap between the atom pair and molecular wave functions, and experiments are currently restricted to magnetoassociation. Here we model realistic production of a quantum degenerate gas of stable molecules via two-photon photoassociation of Bose-condensed atoms. An adiabatic change of the laser frequency converts the initial atomic condensate almost entirely into stable molecular condensate, even for low-intensity lasers. Results for dipolar LiNa provide an upper bound on the necessary photoassociation laser intensity for alkali-metal atoms {approx}30 W/cm{sup 2}, indicating a feasible path to quantum degenerate molecules beyond magnetoassociation.

  17. Creating a Quantum Degenerate Gas of Stable Molecules via Weak Photoassociation

    E-print Network

    Matt Mackie; Pierre Phou

    2010-08-10

    Quantum degenerate molecules represent a new paradigm for fundamental studies and practical applications. Association of already quantum degenerate atoms into molecules provides a crucial shortcut around the difficulty of cooling molecules to ultracold temperatures. Whereas association can be induced with either laser or magnetic fields, photoassociation requires impractical laser intensity to overcome poor overlap between the atom pair and molecular wavefunctions, and experiments are currently restricted to magnetoassociation. Here we model realistic production of a quantum degenerate gas of stable molecules via two-photon photoassociation of Bose-condensed atoms. An adiabatic change of the laser frequency converts the initial atomic condensate almost entirely into stable molecular condensate, even for low-intensity lasers. Results for dipolar LiNa provide an upper bound on the necessary photoassociation laser intensity for alkali-metal atoms ~30 W/cm^2, indicating a feasible path to quantum degenerate molecules beyond magnetoassociation.

  18. Quantum criticality of one-dimensional multicomponent Fermi gas with strongly attractive interaction

    NASA Astrophysics Data System (ADS)

    He, Peng; Jiang, Yuzhu; Guan, Xiwen; He, Jinyu

    2015-01-01

    Quantum criticality of strongly attractive Fermi gas with SU(3) symmetry in one dimension is studied via the thermodynamic Bethe ansatz (TBA) equations. The phase transitions driven by the chemical potential ? , effective magnetic field H1, H2 (chemical potential biases) are analyzed at the quantum criticality. The phase diagram and critical fields are analytically determined by the TBA equations in the zero temperature limit. High accurate equations of state, scaling functions are also obtained analytically for the strong interacting gases. The dynamic exponent z=2 and correlation length exponent ? =1/2 read off the universal scaling form. It turns out that the quantum criticality of the three-component gases involves a sudden change of density of states of one cluster state, two or three cluster states. In general, this method can be adapted to deal with the quantum criticality of multicomponent Fermi gases with SU(N) symmetry.

  19. Ideals and Category Typicality

    ERIC Educational Resources Information Center

    Kim, ShinWoo; Murphy, Gregory L.

    2011-01-01

    Barsalou (1985) argued that exemplars that serve category goals become more typical category members. Although this claim has received support, we investigated (a) whether categories have a single ideal, as negatively valenced categories (e.g., cigarette) often have conflicting goals, and (b) whether ideal items are in fact typical, as they often…

  20. OBTAINING LAWS OF THERMODYNAMICS FOR IDEAL GASES USING ELASTIC COLLISIONS

    E-print Network

    Montgomery-Smith, Stephen

    of gas B in the right half of the container. The molecules obey Newton's laws of motion, with elastic's laws of motion are all that are needed to predict the ideal gas laws, and that the collisionsOBTAINING LAWS OF THERMODYNAMICS FOR IDEAL GASES USING ELASTIC COLLISIONS STEPHEN MONTGOMERY

  1. Mesoscopic behaviour of the neutral Fermi gas 3He confined in quantum wires

    NASA Astrophysics Data System (ADS)

    Phillipson, S. L.; Guénault, A. M.; Fisher, S. N.; Pickett, G. R.; Thibault, P. J. Y.

    1998-10-01

    The behaviour of electron gases in restricted geometries provides a means to explore the fundamental quantum-mechanical properties of fermion gases at mesoscopic length scales. But the existence of Coulomb repulsion between electrons unavoidably complicates the physics. Quantum gases of neutral fermions - such as 3He quasiparticles in a dilute solution of 3He in 4He, cooled to millikelvin temperatures - therefore offer a means of probing regimes completely inaccessible to electronic systems. Here we demonstrate the quantum exclusion of a 3He fermion gas from a network of narrow channels, connected to a reservoir of 3He/4He solution. The effect is expected from simple quantum-mechanical arguments, which predict that the 3He atoms cannot enter the channels when their wavelength exceeds ?2 times the channel width. By adjusting the temperature of the solution, the energy of the particles and hence their average wavelength can becontrolled. In this way, we observe temperature-dependent changes in the penetration of the 3He quasiparticles into the channels. Our results demonstrate the macroscopic response of an atomic gas to basic quantum-mechanical restrictions at the mesoscopic level.

  2. Test of the quantumness of atom-atom correlations in a bosonic gas

    E-print Network

    D. Ivanov; S. Wallentowitz

    2006-03-16

    It is shown how the quantumness of atom-atom correlations in a trapped bosonic gas can be made observable. Application of continuous feedback control of the center of mass of the atomic cloud is shown to generate oscillations of the spatial extension of the cloud, whose amplitude can be directly used as a characterization of atom-atom correlations. Feedback parameters can be chosen such that the violation of a Schwarz inequality for atom-atom correlations can be tested at noise levels much higher than the standard quantum limit.

  3. Trace-gas sensing using the compliance voltage of an external cavity quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Phillips, Mark C.; Taubman, Matthew S.

    2013-05-01

    We present experimental demonstration of a new chemical sensing technique based on intracavity absorption in an external cavity quantum cascade laser (ECQCL). This new technique eliminates the need for an infrared photodetector and gas cell by detecting the intracavity absorption spectrum in the compliance voltage of the laser device itself. To demonstrate and characterize the technique, we measure infrared absorption spectra of chemicals including acetone and Freon-134a. Sub-ppm detection limits in one second are achieved, with the potential for increased sensitivity after further optimization. The technique enables development of handheld, high-sensitivity, and high-accuracy trace gas sensors for in-field use.

  4. Carbon Dioxide Gas Sensing Application of GRAPHENE/Y2O3 Quantum Dots Composite

    NASA Astrophysics Data System (ADS)

    Nemade, K. R.; Waghuley, S. A.

    Graphene/Y2O3 quantum dots (QDs) composite was investigated towards the carbon dioxide (CO2) gas at room temperature. Graphene synthesized by electrochemical exfoliation of graphite. The composite prepared by mixing 20-wt% graphene into the 1 g Y2O3 in organic medium (acetone). The chemiresistor of composite prepared by screen-printing on glass substrate. The optimum value of sensing response (1.08) was showed by 20-wt% graphene/Y2O3 QDs composite. The excellent stability with optimum sensing response evidenced for the composite. The gas sensing mechanism discussed on the basis of electron transfer reaction.

  5. Probing the Quantum State of a 1D Bose Gas Using Off-Resonant Light Scattering

    SciTech Connect

    Sykes, A. G. [Jack Dodd Centre for Quantum Technology, Department of Physics, University of Otago, PO Box 56, Dunedin (New Zealand); Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ballagh, R. J. [Jack Dodd Centre for Quantum Technology, Department of Physics, University of Otago, PO Box 56, Dunedin (New Zealand)

    2011-12-30

    We present a theoretical treatment of coherent light scattering from an interacting 1D Bose gas at finite temperatures. We show how this can provide a nondestructive measurement of the atomic system states. The equilibrium states are determined by the temperature and interaction strength, and are characterized by the spatial density-density correlation function. We show how this correlation function is encoded in the angular distribution of the fluctuations of the scattered light intensity, thus providing a sensitive, quantitative probe of the density-density correlation function and therefore the quantum state of the gas.

  6. VOLUME 87, NUMBER 17 P H Y S I C A L R E V I E W L E T T E R S 22 OCTOBER 2001 Transition from Collisionless to Hydrodynamic Behavior in an Ultracold Fermi Gas

    E-print Network

    Jin, Deborah

    first principles they provide an ideal testing ground for many-body theories of quantum fluids Collisionless to Hydrodynamic Behavior in an Ultracold Fermi Gas S. D. Gensemer and D. S. Jin JILA, Quantum atomic gas provides a sensitive probe of interactions. By studying the lowest frequency excitations

  7. Widely tunable quantum cascade lasers with coupled cavities for gas detection

    Microsoft Academic Search

    Peter Fuchs; Jochen Seufert; Johannes Koeth; Julia Semmel; Sven Höfling; Lukas Worschech; Alfred Forchel

    2010-01-01

    The authors report the fabrication of widely tunable monolithic quantum cascade lasers (QCLs) with coupled Fabry-Pérot (FP) cavities on indium phosphide. Quasicontinuous tuning of the single mode emission over a total spectral range of 242 nm was realized at two regions between 8.394 and 8.785 mum. An absorption experiment with ammonia shows principle feasibility of gas detection with multisegment QCL

  8. Quantum scattering theory of rotational relaxation and spectral line shapes in H2He gas mixtures

    Microsoft Academic Search

    Richard Shafer; Roy G. Gordon

    1973-01-01

    A systematic study is presented of the rotational relaxation and spectral line shape properties of dilute gas mixtures of H2 in He, in an effort to determine the radial and angular dependence of the H2&sngbnd;He intermolecular potential. The quantum mechanical theory of relaxation in gases is reviewed, and we express the results in terms of a matrix of cross sections

  9. Energy Band Structure of the Electron Gas in Periodic Quantum Wells

    NASA Astrophysics Data System (ADS)

    Mao, Sheng-Hong; Ma, Yu-Ting; Xue, Ju-Kui

    2012-08-01

    The energy band structure and current density of electron gas with an exchange-correlation effect in periodic quantum wells are discussed. It is found that the energy band shows a swallowtail structure at the boundary of the first Brillouin zone when the electron exchange-correlation effect is presented and the average electron density is smaller than a critical value. The energy band structure is closely related to the current density of the system.

  10. Lattice Boltzmann and quantum lattice gas representations of one-dimensional magnetohydrodynamic turbulence

    Microsoft Academic Search

    Linda Vahala; George Vahala; Jeffrey Yepez

    2003-01-01

    A simplified one-dimensional (1D) magnetohydrodynamics (MHD) is solved using a lattice Boltzmann and a quantum lattice gas model. It is shown that the magnetic field decreases the strength of the velocity shock fronts, with marked spikes in the magnetic field strength that gradually broaden in time. There is very good agreement between the lattice Boltzmann model—a representation of non-linear systems

  11. Quantum Degeneracy Effect on the Performance of a Bose Ericsson Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Lin, B.; He, J.; Chen, J.

    2003-07-01

    The Ericsson refrigeration cycle working with an ideal Bose gas is called the Bose Ericsson refrigeration cycle. The effect of quantum degeneracy on the performance of the cycle is investigated, based on the thermodynamic properties of an ideal Bose gas. The inherent regenerative losses of the cycle are analyzed, and the coefficient of performance and the refrigeration load of the cycle are calculated. The results obtained here are compared with those derived from the classical Ericsson refrigeration cycle using an ideal gas as the working substance. General performance characteristics of the Bose Ericsson refrigeration cycle are revealed.

  12. The Ideal Online Course

    Microsoft Academic Search

    Alison A. Carr-chellman; Philip C. Duchastel

    2001-01-01

    ALISONCARR-CHELLMAN AND PHILIP DUCHASTEL ABSTRACT THIS PAPER ADDRESSES MANY OF THE KEY ISSUES facing designers of web- based university level courses. Drawing from experienc in distance educa- tion and web-based design, we develop a set of key components to be addressed when creating an 'ideal' online course. Such an analysis forces a consideration of what constitutes good online teaching as

  13. Recurrence Time in the Quantum Dynamics of the 1D Bose Gas

    NASA Astrophysics Data System (ADS)

    Kaminishi, Eriko; Sato, Jun; Deguchi, Tetsuo

    2015-06-01

    Recurrence time is evaluated for some initial quantum states in the one-dimensional Bose gas with repulsive short-range interactions. In the relatively strong and weak coupling cases some different types of initial states show almost complete recurrence and the estimates of recurrence time are proportional to some powers of the system size at least in some range of the system size. They are much longer than in the case of free particles such as 100 times. In the free-bosonic and free-fermionic regimes we evaluate the recurrence time rigorously, which is proportional to the square of the system size. The estimate of recurrence time is given by the order of ten milliseconds in the corresponding experimental systems of cold atoms trapped in one dimension of ten micrometers in length. It is much shorter than the estimate in a generic quantum many-body system, which may be as long as the age of the universe.

  14. NMR dynamics of quantum discord for spin-carrying gas molecules in a closed nanopore

    SciTech Connect

    Yurishchev, M. A., E-mail: yur@itp.ac.ru [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation)

    2014-11-15

    A local orthogonal transformation that transforms any centrosymmetric density matrix of a two-qubit system to the X form has been found. A piecewise-analytic-numerical formula Q = min(Q{sub ?/2}, Q{sub ?}, Q{sub 0}), where Q{sub ?/2} and Q{sub 0} are analytical expressions and the branch Q{sub 0?} can be obtained only by numerically searching for the optimal measurement angle ? ? (0, ?/2), is proposed to calculate the quantum discord Q of a general X state. The developed approaches have been applied for a quantitative description of the recently predicted flickering (periodic disappearance and reappearance) of the quantum-information pair correlation between nuclear 1/2 spins of atoms or molecules of a gas (for example, {sup 129}Xe) in a bounded volume in the presence of a strong magnetic field.

  15. Unravelling the quantum-entanglement effect of noble gas coordination on the spin ground state of CUO

    E-print Network

    Tecmer, Pawel; Legeza, Ors; Reiher, Markus

    2013-01-01

    The accurate description of the complexation of the CUO molecule by Ne and Ar noble gas matrices represents a challenging task for present-day quantum chemistry. Especially, the accurate prediction of the spin ground state of different CUO--noble-gas complexes remains elusive. In this work, the interaction of the CUO unit with the surrounding noble gas matrices is investigated in terms of complexation energies and dissected into its molecular orbital quantum entanglement patterns. Our analysis elucidates the anticipated singlet--triplet ground-state reversal of the CUO molecule diluted in different noble gas matrices and demonstrates that the strongest uranium-noble gas interaction is found for CUOAr4 in its triplet configuration.

  16. On the dynamics of point vortices in a quantum gas confined in an annular region

    E-print Network

    Markus Lakaniemi

    2008-05-29

    The dynamics of one and two pointlike vortices in a planar quantum gas of spin-0 particles confined in an annular region is considered. New analytical and numerical solutions are found. The concept of stationarity radius, related to the doubly connected nature of the annulus, is defined. It is seen that the existence of these radii has great impact on the behaviour of the vortices. It is shown that, because of the existence of the stationarity radii, vortices exhibit similar behaviour regardless of the sign of their winding number. The energetically stable vortex solutions are studied qualitatively.

  17. Quantum and Thermal Effects of Dark Solitons in a One-Dimensional Bose Gas

    SciTech Connect

    Martin, A. D.; Ruostekoski, J. [School of Mathematics, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2010-05-14

    We numerically study the imprinting and dynamics of dark solitons in a bosonic atomic gas in a tightly confined one-dimensional harmonic trap both with and without an optical lattice. Quantum and thermal fluctuations are synthesized within the truncated Wigner approximation in the quasicondensate description. We track the soliton coordinates and calculate position and velocity uncertainties. We find that the phase fluctuations lower the classically predicted soliton speed and seed instabilities. Individual runs show interactions of solitons with sound waves, splitting, and disappearing solitons.

  18. Quantum anomaly, universal relations, and breathing mode of a two-dimensional Fermi gas.

    PubMed

    Hofmann, Johannes

    2012-05-01

    In this Letter, we show that the classical SO(2,1) symmetry of a harmonically trapped Fermi gas in two dimensions is broken by quantum effects. The anomalous correction to the symmetry algebra is given by a two-body operator that is well known as the contact. Taking into account this modification, we are able to derive the virial theorem for the system and a universal relation for the pressure of a homogeneous gas. The existence of an undamped breathing mode is associated with the classical symmetry. We provide an estimate for the anomalous frequency shift of this oscillation at zero temperature and compare the result with a recent experiment by [E. Vogt et al., Phys. Rev. Lett. 108, 070404 (2012)]. Discrepancies are attributed to finite temperature effects. PMID:22681087

  19. AlAs quantum wells: Transport properties of the two-dimensional electron gas

    NASA Astrophysics Data System (ADS)

    Gold, A.; Marty, R.

    2007-10-01

    We present a theory of the transport properties at zero temperature of the electron gas in AlAs. The two-dimensional electron gas in AlAs has a valley degeneracy gv=1 for a quantum well width L Lc. We calculate the mobility for interface-roughness scattering and for impurity scattering. In addition we discuss the single-particle relaxation time (Dingle temperature) and the magnetoresistance in a parallel magnetic field. We discuss how transport measurements can be used to get information about microscopic parameters of disorder and many-body effects. Experimental results obtained for the mobility, the magnetoresistance, and the metal-insulator transition are discussed and compared with our theory.

  20. Ideal intersections for radio-frequency trap networks

    E-print Network

    Janus H. Wesenberg

    2009-01-19

    We investigate the possible form of ideal intersections for two-dimensional rf trap networks suitable for quantum information processing with trapped ions. We show that the lowest order multipole component of the rf field that can contribute to an ideal intersection is a hexapole term uniquely determined by the tangents of the intersecting paths. The corresponding ponderomotive potential does not provide any confinement perpendicular to the paths if these intersect at right angles, indicating that ideal right-angle X intersections are impossible to achieve with hexapole fields. Based on this result, we propose an implementation of an ideal oblique-X intersection using a three-dimensional electrode structure.

  1. Collective motions of a quantum gas confined in a harmonic trap

    SciTech Connect

    Song, Dae-Yup [Department of Physics, Sunchon National University, Suncheon 540-742 (Korea, Republic of)

    2005-08-15

    Single-component quantum gas confined in a harmonic potential, but otherwise isolated, is considered. From the invariance of the system of the gas under a displacement-type transformation, it is shown that the center of mass oscillates along a classical trajectory of a harmonic oscillator. It is also shown that this harmonic motion of the center has, in fact, been implied by Kohn's theorem. If there is no interaction between the atoms of the gas, the system in a time-independent isotropic potential of frequency {nu}{sub c} is invariant under a squeeze-type unitary transformation, which gives collective radial breathing motion of frequency 2{nu}{sub c} to the gas. The amplitudes of the oscillating and breathing motions from the exact invariances could be arbitrarily large. For a Fermi system, appearance of 2{nu}{sub c} mode of the large breathing motion indicates that there is no interaction between the atoms, except for a possible long-range interaction through the inverse-square-type potential.

  2. Interacting Generalized Cosmic Chaplygin Gas in Loop Quantum Cosmology: A Singularity Free Universe

    NASA Astrophysics Data System (ADS)

    Chowdhury, Ratul; Rudra, Prabir

    2013-02-01

    In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by Loop quantum cosmology. Dark energy in the form of Generalized Cosmic Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is taken into account in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy model. Graphs and phase diagrams are drawn to study the variations of these parameters. It is seen that the background dynamics of Generalized Cosmic Chaplygin gas is completely consistent with the notion of an accelerated expansion in the late universe. From the graphs, generalized cosmic Chaplygin gas is identified as a dark fluid with a lesser negative pressure compared to Modified Chaplygin gas, thus supporting a `No Big Rip' cosmology. It has also been shown that in this model the universe follows the power law form of expansion around the critical point, which is consistent with the known results. Future singularities that may be formed in this model as an ultimate fate of the universe has been studied in detail. It was found that the model is completely free from any types of future singularities.

  3. Interacting Generalised Cosmic Chaplygin gas in Loop quantum cosmology: A singularity free universe

    E-print Network

    Ratul Chowdhury; Prabir Rudra

    2012-04-13

    In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by Loop quantum cosmology. Dark energy in the form of Generalised Cosmic Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is taken into account in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy model. Graphs and phase diagrams are drawn to study the variations of these parameters. It is seen that the background dynamics of Generalised Cosmic Chaplygin gas is completely consistent with the notion of an accelerated expansion in the late universe. From the graphs, generalised cosmic Chaplygin gas is identified as a dark fluid with a lesser negative pressure compared to Modified Chaplygin gas, thus supporting a 'No Big Rip' cosmology. It has also been shown that in this model the universe follows the power law form of expansion around the critical point, which is consistent with the known results. Future singularities that may be formed in this model as an ultimate fate of the universe has been studied in detail. It was found that the model is completely free from any types of future singularities.

  4. Ideal Integrating Bolometer

    NASA Technical Reports Server (NTRS)

    Kogut, A.; DiPirro, M.; Moseley, S. H.

    2004-01-01

    We describe a new "ideal integrator" bolometer as a prototype for a new generation of sensitive, flexible far-IR detectors suitable for use in large arrays. The combination of a non-dissipative sensor coupled with a fast heat switch provides breakthrough capabilities in both sensitivity and operation. The bolometer temperature varies linearly with the integrated infrared power incident on the detector, and may be sampled intermittently without loss of information between samples. The sample speed and consequent dynamic range depend only on the heat switch reset cycle and can be selected in software. Between samples, the device acts as an ideal integrator with noise significantly lower than resistive bolometers. Since there is no loss of information between samples, the device is well-suited for large arrays. A single SQUID readout could process an entire column of detectors, greatly reducing the complexity, power requirements, and cost of readout electronics for large pixel arrays.

  5. Delivering ideal employee experiences.

    PubMed

    Weiss, Marjorie D; Tyink, Steve; Kubiak, Curt

    2009-05-01

    Employee-centric strategies have moved from employee satisfaction and brand awareness to employee "affinity" or "attachment." In today's marketplace, occupational health nurses understand that differentiation (i.e., the perception of uniqueness) is the direct result of superior employee interactions, which lead to better employee care, enduring employee relationships, loyal employees, and satisfied employers. What drives employees to occupational health nurse attachment? The answer is a passion for rising above the competition to create ideal employee experiences. PMID:19492760

  6. FK-DLR properties of a quantum multi-type Bose-gas with a repulsive interaction

    NASA Astrophysics Data System (ADS)

    Suhov, Y.; Stuhl, I.

    2014-08-01

    The paper extends earlier results from Suhov and Kelbert ["FK-DLR states of a quantum Bose-gas with a hardcore interaction," arXiv:1304.0782] and Suhov et al. ["Shift-invariance for FK-DLR states of a 2D quantum Bose-gas," arXiv:1304.4177] about infinite-volume quantum bosonic states (FK-DLR states) to the case of multi-type particles with non-negative interactions. (An example is a quantum Widom-Rowlinson model.) Following the strategy from Suhov and Kelbert and Suhov et al., we establish that, for the values of fugacity z ? (0, 1) and inverse temperature ? > 0, finite-volume Gibbs states form a compact family in the thermodynamic limit. Next, in dimension two we show that any limit-point state (an FK-DLR state in the terminology adopted in Suhov and Kelbert and Suhov et al.) is translation-invariant.

  7. Investigation of the full configuration interaction quantum Monte Carlo method using homogeneous electron gas models.

    PubMed

    Shepherd, James J; Booth, George H; Alavi, Ali

    2012-06-28

    Using the homogeneous electron gas (HEG) as a model, we investigate the sources of error in the "initiator" adaptation to full configuration interaction quantum Monte Carlo (i-FCIQMC), with a view to accelerating convergence. In particular, we find that the fixed-shift phase, where the walker number is allowed to grow slowly, can be used to effectively assess stochastic and initiator error. Using this approach we provide simple explanations for the internal parameters of an i-FCIQMC simulation. We exploit the consistent basis sets and adjustable correlation strength of the HEG to analyze properties of the algorithm, and present finite basis benchmark energies for N = 14 over a range of densities 0.5 ? r(s) ? 5.0 a.u. A single-point extrapolation scheme is introduced to produce complete basis energies for 14, 38, and 54 electrons. It is empirically found that, in the weakly correlated regime, the computational cost scales linearly with the plane wave basis set size, which is justifiable on physical grounds. We expect the fixed-shift strategy to reduce the computational cost of many i-FCIQMC calculations of weakly correlated systems. In addition, we provide benchmarks for the electron gas, to be used by other quantum chemical methods in exploring periodic solid state systems. PMID:22755559

  8. An efficient and accurate quantum lattice-gas model for the many-body Schrödinger wave equation

    Microsoft Academic Search

    Jeffrey Yepez; Bruce Boghosian

    2002-01-01

    Presented is quantum lattice-gas model for simulating the time-dependent evolution of a many-body quantum mechanical system of particles governed by the non-relativistic Schrödinger wave equation with an external scalar potential. A variety of computational demonstrations are given where the numerical predictions are compared with exact analytical solutions. In all cases, the model results accurately agree with the analytical predictions and

  9. Investigation of biomass steam gasification gas using a GaAs based quantum cascade laser emitting at 11 ?m

    Microsoft Academic Search

    M. Lackner; Ch. Forsich; F. Winter; S. Anders; G. Strasser

    2003-01-01

    A GaAs-based quantum cascade laser was used to record the absorption spectrum of product gas from a biomass steam gasification plant. The quantum cascade laser, processed as distributed feedback laser, emitted single mode. Its emission wavelength was tuned from 886.76 to 889.16 cm?1 by sweeping the operation temperature of the laser from 185 to 225 K. The spectrum of the

  10. Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition.

    PubMed

    Landig, Renate; Brennecke, Ferdinand; Mottl, Rafael; Donner, Tobias; Esslinger, Tilman

    2015-01-01

    The dynamic structure factor is a central quantity describing the physics of quantum many-body systems, capturing structure and collective excitations of a material. In condensed matter, it can be measured via inelastic neutron scattering, which is an energy-resolving probe for the density fluctuations. In ultracold atoms, a similar approach could so far not be applied because of the diluteness of the system. Here we report on a direct, real-time and nondestructive measurement of the dynamic structure factor of a quantum gas exhibiting cavity-mediated long-range interactions. The technique relies on inelastic scattering of photons, stimulated by the enhanced vacuum field inside a high finesse optical cavity. We extract the density fluctuations, their energy and lifetime while the system undergoes a structural phase transition. We observe an occupation of the relevant quasi-particle mode on the level of a few excitations, and provide a theoretical description of this dissipative quantum many-body system. PMID:25944151

  11. Microscopy of a Quantum Gas in a 2D Optical Lattice

    NASA Astrophysics Data System (ADS)

    Bakr, Waseem; Peng, Amy; Tai, Ming; Ma, Ruichao; Jotzu, Gregor; Gillen, Jonathon; Foelling, Simon; Greiner, Markus

    2010-03-01

    Ultracold quantum gases in optical lattices provide a rich experimental toolbox for simulating the physics of condensed matter systems. With atoms in the lattice playing the role of electrons or Cooper pairs in real materials, it is possible to experimentally realize condensed matter Hamiltonians in a controlled way. To realize the full potential of such quantum simulations, we have created a quantum gas microscope (NA = 0.8) which can spatially resolve the atoms in the optical lattice at the single site level, and project arbitrary potential landscapes onto the atoms by combining the high resolution optics with static holographic masks or a spatial light modulator. The high resolution microscope operates with the atoms trapped in a two dimensional optical lattice at a distance of 10 microns from a glass surface that is part of the microscope. We have experimentally verified a resolution of ˜ 600 nm, providing the capability to study the phase diagram of the Bose Hubbard model by measuring occupation number at individual sites.

  12. Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition

    PubMed Central

    Landig, Renate; Brennecke, Ferdinand; Mottl, Rafael; Donner, Tobias; Esslinger, Tilman

    2015-01-01

    The dynamic structure factor is a central quantity describing the physics of quantum many-body systems, capturing structure and collective excitations of a material. In condensed matter, it can be measured via inelastic neutron scattering, which is an energy-resolving probe for the density fluctuations. In ultracold atoms, a similar approach could so far not be applied because of the diluteness of the system. Here we report on a direct, real-time and nondestructive measurement of the dynamic structure factor of a quantum gas exhibiting cavity-mediated long-range interactions. The technique relies on inelastic scattering of photons, stimulated by the enhanced vacuum field inside a high finesse optical cavity. We extract the density fluctuations, their energy and lifetime while the system undergoes a structural phase transition. We observe an occupation of the relevant quasi-particle mode on the level of a few excitations, and provide a theoretical description of this dissipative quantum many-body system. PMID:25944151

  13. Kelvin's ideal foam structure

    NASA Astrophysics Data System (ADS)

    Weaire, Denis

    2009-04-01

    Among his many extraordinary accomplishments, Kelvin was a pioneer of crystallography, elasticity and materials science. These interests came together to inspire his speculation on the nature of the ether in 1887. He conceived it to be an ordered liquid foam, of minimal surface area. Kelvin's ideal structure of foam has been realised in the laboratory only recently. In the meantime it was surpassed (in terms of surface area minimisation) by the Weaire-Phelan foam, which is the basis for one of the main buildings of the Beijing Olympics.

  14. Poset Resolutions of Monomial Ideals

    E-print Network

    Clark, Timothy B P

    2008-01-01

    We introduce the class of lattice-linear monomial ideals and use the LCM-lattice to give an explicit construction for their minimal free resolution. The class of lattice-linear ideals includes (among others) the class of monomial ideals with linear free resolution and the class of Scarf monomial ideals. Our main tool is a new construction by Tchernev that produces from a map of posets $\\eta:P\\lra\\mbb{N}^n$ a sequence of multigraded modules and maps.

  15. Logic of infinite quantum systems

    Microsoft Academic Search

    Daniele Mundici

    1993-01-01

    Limits of sequences of finite-dimensional (AF)C*-algebras, such as the CAR algebra for the ideal Fermi gas, are a standard mathematical tool to describe quantum statistical systems arising as thermodynamic limits of finite spin systems. Only in the infinite-volume limit one can, for instance, describe phase transitions as singularities in the thermodynamic potentials, and handle the proliferation of physically inequivalent Hilbert

  16. Common physical mechanism for integer and fractional quantum Hall effects

    E-print Network

    Jianhua wang; Kang Li; Shuming Long; Yi Yuan

    2012-01-24

    Integer and fractional quantum Hall effects were studied with different physics models and explained by different physical mechanisms. In this paper, the common physical mechanism for integer and fractional quantum Hall effects is studied, where a new unified formulation of integer and fractional quantum Hall effect is presented. Firstly, we introduce a 2-dimensional ideal electron gas model in the presence of strong magnetic field with symmetry gauge, and the transverse electric filed $\\varepsilon_2$ is also introduced to balance Lorentz force. Secondly, the Pauli equation is solved where the wave function and energy levels is given explicitly. Thirdly, after the calculation of the degeneracy density for 2-dimensional ideal electron gas system, the Hall resistance of the system is obtained, where the quantum Hall number $\

  17. The Quantum Dynamics of a Dilute Gas in a 3D BCC Optical Lattice

    NASA Astrophysics Data System (ADS)

    Reichl, Linda; Boretz, Yingyue

    2015-03-01

    The classical and quantum dynamics of a dilute gas of rubidium atoms, in a 3D body-centered cubic optical lattice, is studied for a range of polarizations of the laser beams forming the lattice. The relative polarization of the lasers determines the the structure of the potential energy seen by the rubidium atoms. If three pairs of in-phase mutually perpendicular laser beams, with the same wavelength, form the lattice, only a limited range of possible couplings can be realized in the lab. We have determined the band structure of the BCC optical lattice for all theoretically possible couplings, and find that the band structure for lattices realizable in the lab, differs significantly from that expected for a BCC crystal. As coupling is increased, the lattice becomes increasingly chaotic and it becomes possible to produce band structure that has qualitative similarity to a BCC. Welch Foundation

  18. Dual quantum cascade laser trace gas instrument with astigmatic Herriott cell at high pass number.

    PubMed

    McManus, J Barry; Zahniser, Mark S; Nelson, David D

    2011-02-01

    We have developed and demonstrated a high-sensitivity trace gas instrument employing two mid-infrared quantum cascade lasers and an astigmatic Herriott sample cell with up to a 240?m path length. Several aspects of astigmatic Herriott cell optics have been addressed to enable operation at a high pass number (up to 554), including aberrations and pattern selection to minimize interference fringes. The new instrument design, based on the 200?m cell, can measure various atmospheric trace gases, depending on the installed lasers, with multiple trace gases measured simultaneously. Demonstrated concentration noise levels (1?s average) are 40?parts per trillion [(ppt) 10(-12)] for formaldehyde, 10?ppt for carbonyl sulfide, 110?ppt for hydrogen peroxide (H2O2), and 180?ppt for nitrous acid (HONO). High-precision measurements of nitrous oxide and methane have been recorded at the same time as high-sensitivity measurements of HONO and H2O2. PMID:21283223

  19. Quasi-Ideal Memory System.

    PubMed

    Sun, Junwei; Shen, Yi

    2015-07-01

    The definition for ideal memory system is so strict that some physical elements cannot exist in the real world. In this paper, an ideal memory system can be extended to generate 15 different kinds of quasi-ideal memory systems, which are included in memory systems as its special cases and are different from ideal memory system. For a system to be a quasi-ideal memory system, it should show three unique fingerprints: 1) the pinched hysteretic loop of a quasi-ideal memory system must be odd symmetrical in the plane; 2) the pinched hysteretic loop of a quasi-ideal memory system must be "self-crossing"; and 3) the slope of tangent line for the pinched hysteresis loop must be strictly monotone in a given period. PMID:25204007

  20. Multi-species trace gas analysis with dual-wavelength quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Jágerská, Jana; Tuzson, Béla; Looser, Herbert; Jouy, Pierre; Hugi, Andreas; Mangold, Markus; Soltic, Patrik; Faist, Jérôme; Emmenegger, Lukas

    2015-04-01

    Simultaneous detection of multiple gas species using mid-IR laser spectroscopy is highly appealing for a large variety of applications ranging from air quality monitoring, medical breath analysis to industrial process control. However, state-of-the-art distributed-feedback (DFB) mid-IR lasers are usually tunable only within a narrow spectral range, which generally leads to one-laser-one-compound measurement strategy. Thus, multi-species detection involves several lasers and elaborate beam combining solutions [1]. This makes them bulky, costly, and highly sensitive to optical alignment, which limits their field deployment. In this paper, we explore an alternative measurement concept based on a dual-wavelength quantum cascade laser (DW-QCL) [2]. Such a laser can emit at two spectrally distinct wavelengths using a succession of two DFB gratings with different periodicities and a common waveguide to produce one output beam. The laser design was optimized for NOx measurements and correspondingly emits single-mode at 5.26 and 6.25 ?m. Electrical separation of the respective laser sections makes it possible to address each wavelength independently. Thereby, it is possible to detect NO and NO2 species with one laser using the same optical path, without any beam combining optics, i.e. in a compact and cost-efficient single-path optical setup. Operated in a time-division multiplexed mode, the spectrometer reaches detection limits at 100 s averaging of 0.5 and 1.5 ppb for NO2 and NO, respectively. The performance of the system was validated against the well-established chemiluminescence detection while measuring the NOx emissions on an automotive test-bench, as well as monitoring the pollution at a suburban site. [1] B. Tuzson, K. Zeyer, M. Steinbacher, J. B. McManus, D. D. Nelson, M. S. Zahniser, and L. Emmenegger, 'Selective measurements of NO, NO2 and NOy in the free troposphere using quantum cascade laser spectroscopy,' Atmospheric Measurement Techniques 6, 927-936 (2013). [2] J. Jágerská, P. Jouy, A. Hugi, B. Tuzson, H. Looser, M. Mangold, M. Beck, L. Emmenegger, and J. Faist, 'Dual-wavelength quantum cascade laser for trace gas spectroscopy,' Applied Physics Letters 105, 161109-161109-4 (2014).

  1. The ideal physician entrepreneur.

    PubMed

    Bottles, K

    2000-01-01

    How does the sometimes elusive and high-stakes world of venture capital really work? How can physician executives with innovative ideas or new technologies approach venture capitalists to help them raise capital to form a start-up company? These important questions are explored in this new column on the physician as entrepreneur. The ideal physician executive is described as: (1) an expert in an area that Wall Street perceives as hot; (2) a public speaker who can enthusiastically communicate scientific and business plans to a variety of audiences; (3) a team leader who is willing to share equity in the company with other employees; (4) a recruiter and a motivator; (5) an implementer who can achieve milestones quickly that allow the company to go public as soon as possible; and (6) a realist who does not resent the terms of the typical deal. The lucrative world of the venture capitalists is foreign territory for physician executives and requires a great idea, charisma, risk-taking, connections, patience, and perseverance to navigate it successfully. PMID:11187408

  2. Local syzygies of multiplier ideals

    Microsoft Academic Search

    Robert Lazarsfeld; Kyungyong Lee

    2007-01-01

    In recent years, multiplier ideals have found many applications in local and\\u000aglobal algebraic geometry. Because of their importance, there has been some\\u000ainterest in the question of which ideals on a smooth complex variety can be\\u000arealized as multiplier ideals. Other than integral closure no local\\u000aobstructions have been known up to now, and in dimension two it was

  3. Ideals of generalized matrix rings

    SciTech Connect

    Budanov, Aleksandr V [Tomsk State University, Tomsk (Russian Federation)

    2011-01-31

    Let R and S be rings, and {sub R}M{sub S} and {sub S}N{sub R} bimodules. In the paper, in terms of isomorphisms of lattices, relationships between the lattices of one-sided and two-sided ideals of the generalized matrix ring and the corresponding lattices of ideals of the rings R and S are described. Necessary and sufficient conditions for a pair of ideals I, J of rings R and S, respectively, to be the main diagonal of some ideal of the ring K are also obtained. Bibliography: 8 titles.

  4. Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas Christian Sanner, Edward J. Su, Aviv Keshet, Ralf Gommers, Yong-il Shin, Wujie Huang, and Wolfgang Ketterle

    E-print Network

    . Su, Aviv Keshet, Ralf Gommers, Yong-il Shin, Wujie Huang, and Wolfgang Ketterle MIT-Harvard Center profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise.1103/PhysRevLett.105.040402 PACS numbers: 03.75.Ss, 05.30.Fk, 67.85.Lm Systems of fermions obey the Pauli

  5. Steric, Quantum, and Electrostatic Effects on S{sub N}2 Reaction Barriers in Gas Phase

    SciTech Connect

    Liu, Shubin; Hu, Hao; Pedersen, Lee G.

    2010-05-13

    Biomolecular nucleophilic substitution reactions, S{sub N}2, are fundamental and commonplace in chemistry. It is the well-documented experimental finding in the literature that vicinal substitution with bulkier groups near the reaction center significantly slows the reaction due to steric hindrance, but theoretical understanding in the quantitative manner about factors dictating the S{sub N}2 reaction barrier height is still controversial. In this work, employing the new quantification approach that we recently proposed for the steric effect from the density functional theory framework, we investigate the relative contribution of three independent effects—steric, electrostatic, and quantum—to the S{sub N}2 barrier heights in gas phase for substituted methyl halide systems, R{sub 1}R{sub 2}R{sub 3}CX, reacting with the fluorine anion, where R{sub 1}, R{sub 2}, and R{sub 3} denote substituting groups and X = F or Cl. We found that in accordance with the experimental finding, for these systems, the steric effect dominates the transition state barrier, contributing positively to barrier heights, but this contribution is largely compensated by the negative, stabilizing contribution from the quantum effect due to the exchange-correlation interactions. Moreover, we find that it is the component from the electrostatic effect that is linearly correlated with the S{sub N}2 barrier height for the systems investigated in the present study. In addition, we compared our approach with the conventional method of energy decomposition in density functional theory as well as examined the steric effect from the wave function theory for these systems via natural bond orbital analysis.

  6. The Confucian ideal of harmony

    Microsoft Academic Search

    Chenyang Li

    2006-01-01

    He ? (harmony, harmonization) is probably the most cherished ideal in Chinese culture. Unfortunately, given its significance, it is arguably also the most understudied. It is therefore high time for some serious study of this ideal. This essay focuses on the Confucian tradition. It first explores the meaning of the Confucian notion of he; then it provides a philosophical analysis

  7. Primary Components of Binomial Ideals

    E-print Network

    Eser, Zekiye

    2014-07-11

    their primary components explicitly. An ideal I ? k[x_(1),….x_(n) ] is cellular if every variable is either a nonzerodivisor modulo I or is nilpotent modulo I. We characterize the minimal primary components of cellular binomial ideals explicitly. Another...

  8. Primary Components of Binomial Ideals 

    E-print Network

    Eser, Zekiye

    2014-07-11

    their primary components explicitly. An ideal I ? k[x_(1),….x_(n) ] is cellular if every variable is either a nonzerodivisor modulo I or is nilpotent modulo I. We characterize the minimal primary components of cellular binomial ideals explicitly. Another...

  9. Quantum Interference as the Source of Steric Asymmetry and Parity Propensity Rules in NO-Rare Gas Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Gijsbertsen, Arjan; Linnartz, Harold; Taatjes, Craig A.; Stolte, Steven

    2006-06-01

    Rotationally inelastic scattering of rare gas atoms and oriented NO molecules exhibits a remarkable alternation in the sign of steric asymmetry between even and odd changes in rotational quantum number. This effect has also been found in full quantum-mechanical scattering calculations. However, until now no physical picture has been given for the alternation. In this work, a newly developed quasi-quantum treatment (QQT) provides the first demonstration that quantum interferences between different orientations of the repulsive potential (that are present in the oriented wave function) are the source of this alternation. Further, from application of the treatment to collisions of nonoriented molecules, a previously unrecognized propensity rule is derived. The angular dependence of the cross sections for excitation to neighboring rotational states with the same parity is shown to be similar, except for a prefactor. Experimental results are presented to support this rule. Unlike conventional quantum-mechanical (or semiclassical) treatments, QQT requires no summation over the orbital angular momentum quantum number l or integration over the impact parameter b. This eliminates the need to solve large sets of coupled differential equations that couple l and rotational state channels among which interference can occur. The QQT provides a physical interpretation of the scattering amplitude that can be represented by a Legendre moment. Application of the QQT on a simple hard-shell potential leads to near-quantitative agreement with experimental observations.

  10. All-Optical Production of a Lithium Quantum Gas Using Narrow-Line Laser Cooling

    E-print Network

    Duarte, P M; Hitchcock, J M; Corcovilos, T A; Yang, T -L; Reed, A; Hulet, R G

    2011-01-01

    We have used the narrow $2S_{1/2} \\rightarrow 3P_{3/2}$ transition in the ultraviolet (UV) to laser cool and magneto-optically trap (MOT) $^{6}$Li atoms. Laser cooling of lithium is usually performed on the $2S_{1/2} \\rightarrow 2P_{3/2}$ (D2) transition, but unresolved hyperfine structure in the excited state hinders the attainment of sub-Doppler temperatures by polarization gradient cooling. Temperatures of roughly twice the Doppler limit, or ~300 {\\mu}K for lithium, are typically achieved. The linewidth of the UV transition is seven times narrower than the D2 line, resulting in lower Doppler cooling temperatures. We show that a MOT operating on the UV transition reaches temperatures as low as 59 {\\mu}K. Furthermore, we show that the light shift of the UV transition in an optical dipole trap at 1070 nm is small and blue-shifted, facilitating efficient loading from the UV MOT. Evaporative cooling of a two spin-state mixture of $^{6}$Li in the optical trap produces a quantum degenerate Fermi gas with $3 \\time...

  11. The degradation of quantum efficiency in negative electron affinity GaAs photocathodes under gas exposure

    NASA Astrophysics Data System (ADS)

    Chanlek, N.; Herbert, J. D.; Jones, R. M.; Jones, L. B.; Middleman, K. J.; Militsyn, B. L.

    2014-02-01

    The influence of O2, CO2, CO, N2, H2 and CH4 on the stability of the quantum efficiency (QE) of a negative electron affinity gallium arsenide (GaAs) photocathode activated with caesium (Cs) and oxygen (O) has been demonstrated for the first time under an extremely high vacuum condition, a base pressure of 1.5 × 10-11 mbar, where the influence of the background gas is minimized. It was found that exposure of a GaAs photocathode to N2, H2 and CH4 does not affect the QE, whereas exposure to O2, CO2 and CO leads to a substantial reduction in photocathode QE. It was also found that the QE of photocathodes which have been degraded under O2 exposure can be recovered to 95% of their initial QE level by the re-caesiation process, while those which have been degraded under exposure to CO and CO2 can only be partly restored to 60-70% of their initial QE levels.

  12. FK-DLR properties of a quantum multi-type Bose-gas with a repulsive interaction

    SciTech Connect

    Suhov, Y., E-mail: yms@statslab.cam.ac.uk [Statistical Laboratory, DPMMS, University of Cambridge (United Kingdom); Department of Statistics/IME, University of São Paulo (Brazil); IITP, RAS, Moscow (Russian Federation); Stuhl, I., E-mail: izabella@ime.usp.br [University of Debrecen (Hungary); IME, University of São Paulo (Brazil)

    2014-08-01

    The paper extends earlier results from Suhov and Kelbert [“FK-DLR states of a quantum Bose-gas with a hardcore interaction,” http://arxiv.org/abs/arXiv:1304.0782 ] and Suhov et al. [“Shift-invariance for FK-DLR states of a 2D quantum Bose-gas,” http://arxiv.org/abs/arXiv:1304.4177 ] about infinite-volume quantum bosonic states (FK-DLR states) to the case of multi-type particles with non-negative interactions. (An example is a quantum Widom–Rowlinson model.) Following the strategy from Suhov and Kelbert and Suhov et al., we establish that, for the values of fugacity z?(0, 1) and inverse temperature ? > 0, finite-volume Gibbs states form a compact family in the thermodynamic limit. Next, in dimension two we show that any limit-point state (an FK-DLR state in the terminology adopted in Suhov and Kelbert and Suhov et al.) is translation-invariant.

  13. In situ observation of sub-Poissonian atom-number fluctuations in a repulsive 1D Bose gas: quantum quasi-condensate and strongly interacting regimes

    E-print Network

    In situ observation of sub-Poissonian atom-number fluctuations in a repulsive 1D Bose gas: quantum for Quantum-Atom Optics, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia (Dated: March 21, 2011) We report on local measurements of atom number fluctuations

  14. Non-Euclidean ideal spectrometer

    E-print Network

    Earp, Henrique N Sá; Sicca, Vladmir

    2015-01-01

    We describe the mathematical scheme for an anomaly-free ideal spectrometer, based on a 2-dimensional plane medium with conical regions of bounded slope. Moreover, the construction may be realised in many different configurations.

  15. Uranyl complexes with diamide ligands: a quantum mechanics study of chelating properties in the gas phase.

    PubMed

    Coupez, Bernard; Wipff, Georges

    2003-06-01

    We report a quantum mechanical study on the complexes of UO(2)(2+) with diamide ligands L of malonamide and succinamide type, respectively, forming 6- and 7-chelate rings in their bidentate coordination to uranium. The main aims are to (i) assess how strong the chelate effect is (i.e., the preference for bi- versus monodentate binding modes of L), (ii) compare these ligands as a function of the chelate ring size, and (iii) assess the role of neutralizing counterions. For this purpose, we consider UO(2)L(2+), UO(2)L(2)(2+), UO(2)L(3)(2+), and UO(2)X(2)L type complexes with X(-) = Cl(-) versus NO(3)(-). Hartree-Fock and DFT calculations lead to similar trends and reveal the importance of saturation and steric repulsions ("strain") in the first coordination sphere. In the unsaturated UO(2)L(2+), UO(2)L(2)(2+), and UO(2)Cl(2)L complexes, the 7-ring chelate is preferred over the 6-ring chelate, and bidentate coordination is preferred over the monodentate one. However, in the saturated UO(2)(NO(3))(2)L complexes, the 6- and 7-chelating ligands have similar binding energies, and for a given ligand, the mono- and bidentate binding modes are quasi-isoenergetic. These conclusions are confirmed by the calculations of free energies of complexation in the gas phase. In condensed phases, the monodentate form of UO(2)X(2)L complexes should be further stabilized by coordination of additional ligands, as well as by interactions (e.g., hydrogen bonding) of the "free" carbonyl oxygen, leading to an enthalpic preference for this form, compared to the bidentate one. We also considered an isodesmic reaction exchanging one bidentate ligand L with two monoamide analogues, which reveals that the latter are clearly preferred (by 23-14 kcal/mol at the HF level and 24-12 kcal/mol at the DFT level). Thus, in the gas phase, the studied bidentate ligands are enthalpically disfavored, compared to bis-monodentate analogues. The contrast with trends observed in solution hints at the importance of "long range" forces (e.g., second shell interactions) and entropy effects on the chelate effect in condensed phases. PMID:12767210

  16. Trace gas measurements using optically resonant cavities and quantum cascade lasers operating at room temperature

    NASA Astrophysics Data System (ADS)

    Welzel, S.; Lombardi, G.; Davies, P. B.; Engeln, R.; Schram, D. C.; Röpcke, J.

    2008-11-01

    Achieving the high sensitivity necessary for trace gas detection in the midinfrared molecular fingerprint region generally requires long absorption path lengths. In addition, for wider application, especially for field measurements, compact and cryogen free spectrometers are definitely preferable. An alternative approach to conventional linear absorption spectroscopy employing multiple pass cells for achieving high sensitivity is to combine a high finesse cavity with thermoelectrically (TE) cooled quantum cascade lasers (QCLs) and detectors. We have investigated the sensitivity limits of an entirely TE cooled system equipped with an ˜0.5 m long cavity having a small sample volume of 0.3 l. With this spectrometer cavity enhanced absorption spectroscopy employing a continuous wave QCL emitting at 7.66 ?m yielded path lengths of 1080 m and a noise equivalent absorption of 2×10-7 cm-1 Hz-1/2. The molecular concentration detection limit with a 20 s integration time was found to be 6×108 molecules/cm3 for N2O and 2×109 molecules/cm3 for CH4, which is good enough for the selective measurement of trace atmospheric constituents at 2.2 mbar. The main limiting factor for achieving even higher sensitivity, such as that found for larger volume multi pass cell spectrometers, is the residual mode noise of the cavity. On the other hand the application of TE cooled pulsed QCLs for integrated cavity output spectroscopy and cavity ring-down spectroscopy (CRDS) was found to be limited by the intrinsic frequency chirp of the laser. Consequently the accuracy and advantage of an absolute internal absorption calibration, in theory inherent for CRDS experiments, are not achievable.

  17. Ideal near-field thermophotovoltaic cells

    NASA Astrophysics Data System (ADS)

    Molesky, Sean; Jacob, Zubin

    2015-05-01

    We ask the question, what are the ideal characteristics of a near-field thermophotovoltaic cell? Our search leads us to a reformulation of near-field radiative heat transfer in terms of the joint density of electronic states of the emitter-absorber pair in the thermophotovoltaic system. This form reveals that semiconducting materials with narrowband absorption spectra are critical to the energy-conversion efficiency. This essential feature is unavailable in conventional bulk semiconductor cells but can be obtained using low-dimensional materials. Our results show that the presence of matched van Hove singularities resulting from quantum confinement in the emitter and absorber of a thermophotovoltaic cell boosts both the magnitude and spectral selectivity of radiative heat transfer, dramatically improving energy-conversion efficiency. We provide a model near-field thermophotovoltaic system design making use of this idea by employing the van Hove singularities present in carbon nanotubes. Shockley-Queisser analysis shows that the predicted heat transfer characteristics of this model device are fundamentally better than existing thermophotovoltaic designs. Our work paves the way for the use of quantum dots, quantum wells, two-dimensional semiconductors, semiconductor nanowires, and carbon nanotubes as future materials for thermophotovoltaic cells.

  18. Quantum lattice gas model of Dirac particles in 1+1 dimensions

    E-print Network

    Jeffrey Yepez

    2013-07-12

    Presented is a quantum computing representation of Dirac particle dynamics. The approach employs an operator splitting method that is an analytically closed-form product decomposition of the unitary evolution operator. This allows the Dirac equation to be cast as a unitary finite-difference equation in a high-energy limit. The split evolution operator (with separate kinetic and interaction terms) is useful for efficient quantum simulation. For pedagogical purposes, here we restrict the treatment to Dirac particle dynamics in 1+1 spacetime dimensions. Independent derivations of the quantum algorithm are presented and the model's validity is tested in several quantum simulations by comparing the numerical results against analytical predictions. Using the relativistic quantum algorithm in the case when mc^2 >> pc, quantum simulations of a nonrelativistic particle in an external scalar square well and parabolic potential is presented.

  19. Effective medium theory of permeation through ideal polymer networks

    E-print Network

    Yong Wu

    2007-03-02

    The diffusion process through an ideal polymer network is studied by applying the effective medium theory (EMT) to a lattice-gas model. Polymers are modeled by random walks on the lattice bonds, across which molecules can hop with a certain probability. The steady state current of the system is calculated using the EMT and the results are compared to the simulations.

  20. Betti numbers of transversal monomial ideals

    E-print Network

    Zaare-Nahandi, Rahim

    2008-01-01

    In this paper, by a modification of a previously constructed minimal free resolution for a transversal monomial ideal, the Betti numbers of this ideal is explicitly computed. For convenient characteristics of the ground field, up to a change of coordinates, the ideal of $t$-minors of a generic pluri-circulant matrix is a transversal monomial ideal . Using a Gr\\"obner basis for this ideal, it is shown that the initial ideal of a generic pluri-circulant matrix is a stable monomial ideal when the matrix has two square blocks. By means of the Eliahou-Kervair resolution, the Betti numbers of this initial ideal is computed and it is proved that, for some significant values of $t$, this ideal has the same Betti numbers as the corresponding transversal monomial ideal. The ideals treated in this paper, naturally arise in the study of generic singularities of algebraic varieties.

  1. Use of external cavity quantum cascade laser compliance voltage in real-time trace gas sensing of multiple chemicals

    NASA Astrophysics Data System (ADS)

    Phillips, Mark C.; Taubman, Matthew S.; Kriesel, Jason

    2015-01-01

    We describe a prototype trace gas sensor designed for real-time detection of multiple chemicals. The sensor uses an external cavity quantum cascade laser (ECQCL) swept over its tuning range of 940-1075 cm-1 (9.30-10.7 ?m) at a 10 Hz repetition rate. The sensor was designed for operation in multiple modes, including gas sensing within a multi-pass Heriott cell and intracavity absorption sensing using the ECQCL compliance voltage. In addition, the ECQCL compliance voltage was used to reduce effects of long-term drifts in the ECQCL output power. The sensor was characterized for noise, drift, and detection of chemicals including ammonia, methanol, ethanol, isopropanol, Freon- 134a, Freon-152a, and diisopropyl methylphosphonate (DIMP). We also present use of the sensor for mobile detection of ammonia downwind of cattle facilities, in which concentrations were recorded at 1-s intervals.

  2. Gas

    MedlinePLUS

    ... and pain in the belly—especially after a big meal. Foods that can cause gas Some people naturally produce ... your stomach or throw up . Your breasts are big and sore . The area around your nipples gets darker. You crave certain foods. Or you really dislike certain foods. You feel ...

  3. COMMUTATIVE IDEAL THEORY WITHOUT FINITENESS ...

    E-print Network

    Oct 25, 2005 ... In Section 2 we establish basic properties of irreducible submodules of an .... (iv) ? (iii) Since we have established the equivalence of (i)-(iii), and ..... (vi) By (v), R is quasilocal with maximal ideal M, and M is the adjoint prime.

  4. [Harmony--idea and ideal].

    PubMed

    Scharfetter, C

    1996-03-01

    The concept of the whole as an ideal of gestalt and value is sketched. In the concrete situation of healer and patient a multiperspective approach rather than a realization of wholeness has to be enough, taking into account somatic, physiological, intraindividual-psychological, interpersonal-social and transpersonal aspects of personalities in diagnosis and treatment. PMID:8900879

  5. Carbon Nanomaterials: The Ideal Interconnect

    E-print Network

    Carbon Nanomaterials: The Ideal Interconnect Technology for Next- Generation ICs Hong Li, Chuan Xu-generation ICs. In this research, carbon nanomaterials, with their many attractive properties, are emerging-chip interconnects. In this article, we discuss various car- bon nanomaterials, along with their prospects for next

  6. Failure of the Bell Locality Condition over a Space of Ideal Particles and their Paths

    E-print Network

    Warren Leffler

    2013-02-21

    We construct a space of ideal elements (particles and their paths) to analyze certain aspects of quantum physics. The particles are taken from a model of particle interaction first described by David Deutsch (based on a different but related framework, that of MWI), and the paths are based on Richard Feynman's path-integral formulation of quantum mechanics. By combining the two systems we develop a new approach to quantum mechanics that eliminates various quantum paradoxes.

  7. Betti numbers of transversal monomial ideals

    Microsoft Academic Search

    Rahim Zaare-Nahandi

    2008-01-01

    In this paper, by a modification of a previously constructed minimal free resolution for a transversal monomial ideal, the Betti numbers of this ideal is explicitly computed. For convenient characteristics of the ground field, up to a change of coordinates, the ideal of $t$-minors of a generic pluri-circulant matrix is a transversal monomial ideal . Using a Gr\\\\\\

  8. Two-dimensional electron gas in InGaAs/InAlAs quantum wells Departamento de Fsica Fundamental, Universidad de Salamanca, 37008 Salamanca, Spain

    E-print Network

    Chen, Yong P.

    style analysis. The amplitude R of the envelope function of the SdH oscilla- tions was found to be wellTwo-dimensional electron gas in InGaAs/InAlAs quantum wells E. Diez Departamento de Física on two-dimensional electron gases confined in lattice-matched In0.53Ga0.47As/In0.52Al0.48As quantum wells

  9. M. Bahrami ENSC 461 (S 11) Jet Propulsion Cycle 1 Ideal JetPropulsion Cycle

    E-print Network

    Bahrami, Majid

    M. Bahrami ENSC 461 (S 11) Jet Propulsion Cycle 1 Ideal JetPropulsion Cycle Gas-turbine engines. Aircraft gas turbines operate on an open cycle called jet-propulsion cycle. Some of the major differences between the gas-turbine and jet-propulsion cycles are: gases are expanded in the turbine to a pressure

  10. A Quantum Chemistry Study of Natural Gas Hydrates Mert Atilhan,1

    E-print Network

    Pala, Nezih

    , with shiftings rising from host-guest interactions, and useful patterns in the terahertz region rising from water and academia because of the massive amounts of gas in the form of hydrates in ocean bed and under permafrost of natural gas hydrates requires low temperature (typically lower than 300 K) and moderate pressure

  11. Full Configuration Interaction Quantum Monte Carlo and Diffusion Monte Carlo: A Comparative Study of the 3D Homogeneous Electron Gas

    NASA Astrophysics Data System (ADS)

    Shepherd, James J.; López Ríos, Pablo; Needs, Richard J.; Drummond, Neil D.; Mohr, Jennifer A.-F.; Booth, George H.; Grüneis, Andreas; Kresse, Georg; Alavi, Ali

    2013-03-01

    Full configuration interaction quantum Monte Carlo1 (FCIQMC) and its initiator adaptation2 allow for exact solutions to the Schrödinger equation to be obtained within a finite-basis wavefunction ansatz. In this talk, we explore an application of FCIQMC to the homogeneous electron gas (HEG). In particular we use these exact finite-basis energies to compare with approximate quantum chemical calculations from the VASP code3. After removing the basis set incompleteness error by extrapolation4,5, we compare our energies with state-of-the-art diffusion Monte Carlo calculations from the CASINO package6. Using a combined approach of the two quantum Monte Carlo methods, we present the highest-accuracy thermodynamic (infinite-particle) limit energies for the HEG achieved to date. 1 G. H. Booth, A. Thom, and A. Alavi, J. Chem. Phys. 131, 054106 (2009). 2 D. Cleland, G. H. Booth, and A. Alavi, J. Chem. Phys. 132, 041103 (2010). 3 www.vasp.at (2012). 4 J. J. Shepherd, A. Grüneis, G. H. Booth, G. Kresse, and A. Alavi, Phys. Rev. B. 86, 035111 (2012). 5 J. J. Shepherd, G. H. Booth, and A. Alavi, J. Chem. Phys. 136, 244101 (2012). 6 R. Needs, M. Towler, N. Drummond, and P. L. Ríos, J. Phys.: Condensed Matter 22, 023201 (2010).

  12. Quantum Number Dependence of Lineshift Coefficients Induced by Collisions with Noble Gas Perturbers in the nu(3) Band of NO(2).

    PubMed

    Sumpf; Bouazza; Kissel; Kronfeldt

    2000-02-01

    To complete our study concerning lineshift in the rovibrational spectrum of (14)N(16)O(2), a pulse-driven three-channel lead salt diode laser spectrometer was applied to record high-resolution spectra at room temperature in the 6.2-µm region corresponding to the nu(3) band at low NO(2) concentrations. The shift was studied for collisions with the noble gases He, Ne, Ar, Kr, and Xe. This paper extends our recently published data in order to analyze the quantum number dependence of the shift effect more precisely. Therefore, in this paper, additionally eight unresolved NO(2) doublets covering an enlarged quantum number range (10 gas) and additionally broadening coefficients gamma(NO(2)-noble gas) were determined. Hereby, the experimental data confirm general trends published recently. In this study, in the case of broadening for the lighter rare gases helium, neon, and argon, only a slight decrease of gamma(NO(2)-noble gas) was observed, whereas for the rare gases with a higher atomic weight, i.e., krypton and xenon, a pronounced decrease of gamma(NO(2)-noble gas) with increasing rotational quantum number N(") occurred. All measured lineshift coefficients were negative. The absolute value of the determined lineshift coefficient ||delta(NO(2)-noble gas) || increases with the mass of the noble gas perturber, i.e., ||delta(NO(2)-He) || < ||delta(NO(2)-Ne) || < ||delta(NO(2)-Ar) || < ||delta(NO(2)-Kr) || < ||delta(NO(2)-Xe) ||. Within the studied quantum number range, an increase ||delta(NO(2)-noble gas) || with increase of N(") was observed. A typical trend of the shift and broadening data on the quantum number K(")(a) was not observed. Copyright 2000 Academic Press. PMID:10637106

  13. Ideal combustion of solid fuels

    SciTech Connect

    Ling, S.C.; Pao, H.P.

    1988-01-01

    Unlike the unstable, runaway, combustion of micro-fuel particles, solid fuel in the reconstituted form of a specifically shaped charge was found to have stable and ideal combustion characteristics suitable for the automatic control of combustion rate and temperature. Consequently, most environmental and operational problems associated with the atomized-combustion process can be eliminated. The shaped-charge fuel is applicable for both large power generation as well as for small home heating. 1 ref., 3 figs.

  14. Quantum de Laval nozzle: Stability and quantum dynamics of sonic horizons in a toroidally trapped Bose gas containing a superflow

    SciTech Connect

    Jain, P. [School of Chemical and Physical Sciences, Victoria University of Wellington (New Zealand); Jack Dodd and Dan Walls Centre for Photonics and Ultra Cold Atoms, University of Otago (New Zealand); Bradley, A. S. [ARC Centre of Excellence for Quantum-Atom Optics, Department of Physics, University of Queensland, Brisbane, QLD 4072 (Australia); Gardiner, C. W. [Jack Dodd and Dan Walls Centre for Photonics and Ultra Cold Atoms, University of Otago (New Zealand)

    2007-08-15

    We study an experimentally realizable system containing stable black hole-white hole acoustic horizons in toroidally trapped Bose-Einstein condensates--the quantum de Laval nozzle. We numerically obtain stationary flow configurations and assess their stability using Bogoliubov theory, finding both in hydrodynamic and nonhydrodynamic regimes there exist dynamically unstable regions associated with the creation of positive and negative energy quasiparticle pairs in analogy with the gravitational Hawking effect. The dynamical instability takes the form of a two mode squeezing interaction between resonant pairs of Bogoliubov modes. We study the evolution of dynamically unstable flows using the truncated Wigner method, which confirms the two mode squeezed state picture of the analogue Hawking effect for low winding number.

  15. Quantum dots and etch-induced depletion of a silicon two-dimensional electron gas

    NASA Astrophysics Data System (ADS)

    Klein, L. J.; Lewis, K. L. M.; Slinker, K. A.; Goswami, Srijit; van der Weide, D. W.; Blick, R. H.; Mooney, P. M.; Chu, J. O.; Coppersmith, S. N.; Friesen, Mark; Eriksson, M. A.

    2006-01-01

    The controlled depletion of electrons in semiconductors is the basis for numerous devices. Reactive-ion etching provides an effective technique for fabricating both classical and quantum devices. However, Fermi-level pinning must be carefully considered in the development of small devices, such as quantum dots. Because of depletion, the electrical size of the device is reduced in comparison with its physical dimension. To investigate this issue in modulation-doped silicon single-electron transistors, we fabricate several types of devices in silicon-germanium heterostructures using two different etches, CF4 and SF6. We estimate the depletion width associated with each etch by two methods: (i) conductance measurements in etched wires of decreasing thickness (to determine the onset of depletion), and (ii) capacitance measurements of quantum dots (to estimate the size of the active region). We find that the SF6 etch causes a much smaller depletion width, making it more suitable for device fabrication.

  16. [Mid-infrared distributed-feedback quantum cascade laser-based photoacoustic detection of trace methane gas].

    PubMed

    Tan, Song; Liu, Wan-feng; Wang, Li-jun; Zhang, Jin-chuan; Li, Lu; Liu, Jun-qi; Liu, Feng-qi; Wang, Zhan-guo

    2012-05-01

    There have been considerable interests in methane detection based on infrared absorption spectroscopy for industrial and environment monitoring. The authors report on the realization of photoacoustic detection of methane (CH4) using mid-infrared distributed-feedback quantum cascade laser (DFB-QCL). The absorption line at 1316.83 cm(-1) was selected for CH4 detection, which can be reached by the self-manufactured DFB-QCL source operating in pulsed mode near 7.6 microm at room-temperature. The CH4 gas is filled to a Helmholtz resonant photoacoustic cell, which was equipped with a commercial electret microphone. The DFB-QCL was operated at 234 Hz with an 80 mW optical peak power. A detection limit of 189 parts per billion in volume was derived when the signal-to-noise ratio equaled 1. PMID:22827065

  17. (Fuzzy) Ideals of BN-Algebras.

    PubMed

    Dymek, Grzegorz; Walendziak, Andrzej

    2015-01-01

    The notions of an ideal and a fuzzy ideal in BN-algebras are introduced. The properties and characterizations of them are investigated. The concepts of normal ideals and normal congruences of a BN-algebra are also studied, the properties of them are displayed, and a one-to-one correspondence between them is presented. Conditions for a fuzzy set to be a fuzzy ideal are given. The relationships between ideals and fuzzy ideals of a BN-algebra are established. The homomorphic properties of fuzzy ideals of a BN-algebra are provided. Finally, characterizations of Noetherian BN-algebras and Artinian BN-algebras via fuzzy ideals are obtained. PMID:26125050

  18. (Fuzzy) Ideals of BN-Algebras

    PubMed Central

    Walendziak, Andrzej

    2015-01-01

    The notions of an ideal and a fuzzy ideal in BN-algebras are introduced. The properties and characterizations of them are investigated. The concepts of normal ideals and normal congruences of a BN-algebra are also studied, the properties of them are displayed, and a one-to-one correspondence between them is presented. Conditions for a fuzzy set to be a fuzzy ideal are given. The relationships between ideals and fuzzy ideals of a BN-algebra are established. The homomorphic properties of fuzzy ideals of a BN-algebra are provided. Finally, characterizations of Noetherian BN-algebras and Artinian BN-algebras via fuzzy ideals are obtained. PMID:26125050

  19. Manifestation of quantum resonances and antiresonances in a finite-temperature dilute atomic gas

    SciTech Connect

    Saunders, M.; Halkyard, P. L.; Challis, K. J.; Gardiner, S. A. [Department of Physics, Durham University, Rochester Building, South Road, Durham DH1 3LE (United Kingdom)

    2007-10-15

    We investigate the effect of temperature on resonant and antiresonant dynamics in a dilute atomic gas kicked periodically by a standing-wave laser field. Our numerical calculations are based on a Monte Carlo method for an incoherent mixture of noninteracting plane waves, and show that the atomic dynamics are highly sensitive to the initial momentum width of the gas. We explain this sensitivity by examining the time evolution of individual atomic center-of-mass momentum eigenstates with varying quasimomentum, and we determine analytic expressions for the evolution of the second-order momentum moment to illustrate the range of behaviors.

  20. The manifestation of quantum resonances and antiresonances in a finite temperature dilute atomic gas

    E-print Network

    M. Saunders; P. L. Halkyard; K. J. Challis; S. A. Gardiner

    2007-08-07

    We investigate the effect of temperature on resonant and antiresonant dynamics in a dilute atomic gas kicked periodically by a standing wave laser field. Our numerical calculations are based on a Monte Carlo method for an incoherent mixture of non-interacting plane waves, and show that the atomic dynamics are highly sensitive to the initial momentum width of the gas. We explain this sensitivity by examining the time evolution of individual atomic centre of mass momentum eigenstates with varying quasimomentum, and we have determined analytic expressions for the evolution of the second-order momentum moment to illustrate the range of behaviours.

  1. Linear Syzygies Of Stanley-Reisner Ideals

    Microsoft Academic Search

    V. Reiner; V. Welker

    1998-01-01

    . We give an elementary description of the maps in the linear strandof the minimal free resolution of a square-free monomial ideal, that is, theStanley-Reisner ideal associated to a simplicial complex \\\\Delta. The descriptionis in terms of the homology of the canonical Alexander dual complex \\\\Delta. Asapplications we are able toffl prove for monomial ideals and j = 1 a

  2. IDEAL MAGNETOHYDRODYNAMIC STABILITY OF THE NCSX

    E-print Network

    Martín-Solís, José Ramón

    IDEAL MAGNETOHYDRODYNAMIC STABILITY OF THE NCSX G. Y. FU,a * M. ISAEV,b L. P. KU,a M. MIKHAILOV,b M Received March 1, 2006 Accepted for Publication March 30, 2006 The ideal magnetohydrodynamic (MHD are signifi- cantly more stable than the local infinite-n modes. KEYWORDS: ideal magnetohydrodynamic stability

  3. Closing the Idealization Gap with Theory Generation

    E-print Network

    Wing, Jeannette M.

    property checker logic L protocol P property y/n Figure 1: Basic Approach and a concrete protocol of the concrete messages exchanged in the protocol. It is difficult to produce a good idealization. For example idealization and concrete protocol together. Given a concrete protocol and formalized idealization, we can

  4. Life's Solutions are Not Ideal

    E-print Network

    Bob Eisenberg

    2011-05-01

    Life occurs in ionic solutions, not pure water. The ionic mixtures of these solutions are very different from water and have dramatic effects on the cells and molecules of biological systems, yet theories and simulations cannot calculate their properties. I suggest the reason is that existing theories stem from the classical theory of ideal or simple gases in which (to a first approximation) atoms do not interact. Even the law of mass action describes reactants as if they were ideal. I propose that theories of ionic solutions should start with the theory of complex fluids because that theory is designed to deal with interactions from the beginning. The variational theory of complex fluids is particularly well suited to describe mixtures like the solutions in and outside biological cells. When a component or force is added to a solution, the theory derives - by mathematics alone - a set of partial differential equations that captures the resulting interactions self-consistently. Such a theory has been implemented and shown to be computable in biologically relevant systems but it has not yet been thoroughly tested in equilibrium or flow.

  5. Representation of ideal magnetohydrodynamic modes

    SciTech Connect

    White, R. B. [Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)

    2013-02-15

    One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through {delta}B(vector sign)={nabla} Multiplication-Sign ({xi}(vector sign) Multiplication-Sign B(vector sign)) ensures that {delta}B(vector sign){center_dot}{nabla}{psi}=0 at a resonance, with {psi} labelling an equilibrium flux surface. Also useful for the analysis of guiding center orbits in a perturbed field is the representation {delta}B(vector sign)={nabla} Multiplication-Sign {alpha}B(vector sign). These two representations are equivalent, but the vanishing of {delta}B(vector sign){center_dot}{nabla}{psi} at a resonance is necessary but not sufficient for the preservation of field line topology, and a indiscriminate use of either perturbation in fact destroys the original equilibrium flux topology. It is necessary to find the perturbed field to all orders in {xi}(vector sign) to conserve the original topology. The effect of using linearized perturbations on stability and growth rate calculations is discussed.

  6. Critical points in a relativistic bosonic gas induced by the quantum structure of spacetime

    NASA Astrophysics Data System (ADS)

    Castellanos, E.; Camacho, Abel

    2009-11-01

    It is well known that phase transitions arise if the interaction among particles embodies an attractive as well as a repulsive contribution. In this work it will be shown that the breakdown of Lorentz symmetry, characterized through a deformation in the relation dispersion, plus the bosonic statistics predict the emergence of critical points. In other words, in some quantum gravity models the structure of spacetime implies the emergence of critical points even when no interaction among the particles has been considered.

  7. Optimizing Gas Sensors Based on Quantum Cascade Lasers and Photonic Bandgap Hollow Waveguides

    Microsoft Academic Search

    Christina Young; Susanne Hartwig; Armin Lambrecht; Seong-Soo Kim; Boris Mizaikoff

    2007-01-01

    In the present study, bending losses in conventional hollow waveguides (internally Ag\\/AgI coated) and in photonic bandgap (PBG) hollow waveguides (HWG) are compared based on studies via FT-IR spectroscopy and quantum cascade lasers (QCL). To date, literature on bending losses in hollow waveguides focuses on conventional HWG structures (e.g., silica structural tube with internal Ag\\/AgI coating), whereas the results discussed

  8. ccsd00001653, Exact scaling transform for a unitary quantum gas in a time

    E-print Network

    of spin 1=2 fermionic atoms are currently making rapid progresses. One of the most fascinating properties-potential [3]. Such stability of the strongly interacting Fermi gases opens up fascinating possibilities, e homogeneous gas are universal: they depend only on the Fermi energy and on the temperature. At zero

  9. Statistical mechanics based on fractional classical and quantum mechanics

    SciTech Connect

    Korichi, Z.; Meftah, M. T., E-mail: mewalid@yahoo.com [Physics Department, LRPPS Laboratory, Ouargla University, Ouargla 30000 (Algeria)

    2014-03-15

    The purpose of this work is to study some problems in statistical mechanics based on the fractional classical and quantum mechanics. At first stage we have presented the thermodynamical properties of the classical ideal gas and the system of N classical oscillators. In both cases, the Hamiltonian contains fractional exponents of the phase space (position and momentum). At the second stage, in the context of the fractional quantum mechanics, we have calculated the thermodynamical properties for the black body radiation, studied the Bose-Einstein statistics with the related problem of the condensation and the Fermi-Dirac statistics.

  10. Fuzzy $h$-ideals of hemirings

    E-print Network

    Jianming Zhan; Wies?aw A. Dudek

    2006-05-28

    A characterization of an $h$-hemiregular hemiring in terms of a fuzzy $h$-ideal is provided. Some properties of prime fuzzy $h$-ideals of $h$-hemiregular hemirings are investigated. It is proved that a fuzzy subset $\\zeta$ of a hemiring $S$ is a prime fuzzy left (right) $h$-ideal of $S$ if and only if $\\zeta$ is two-valued, $\\zeta(0) = 1$, and the set of all $x$ in $S$ such that $\\zeta(x) = 1$ is a prime (left) right $h$-ideal of $S$. Finally, the similar properties for maximal fuzzy left (right) $h$-ideals of hemirings are considered.

  11. Pulsatile flow through idealized trabeculae

    NASA Astrophysics Data System (ADS)

    Battista, Nicholas; Miller, Laura

    2013-11-01

    Trabeculae begin to form in the human developing heart for Reynolds numbers on the order of 10. Other hearts, such as the squid heart, have trabeculae for Re on the order of 10 and larger. The effect of trabeculae on the flow in this range of Re is not well understood. In this study, computational fluid dynamics is used to quantify the effects of Reynolds number and idealized trabeculae height on the resulting flows. An adaptive and parallelized version of the immersed boundary method (IBAMR) is used to solve the fluid-structure interaction problem. We see the formation of vortices depends upon Re and trabeculae height. We then explore how the periodicity of the flow effects vortex formation and shear patterns. This is important because it is thought that these dynamic processes are important to the generation of shear at the endothelial surface layer and strains at the epithelial layer, which will aid in proper development and functionality.

  12. [The ideal body: media pedagogy].

    PubMed

    Ribeiro, Rubia Guimarães; da Silva, Karen Schein; Kruse, Maria Henriqueta Luce

    2009-03-01

    We present enunciations that circulate in the media regarding the body, discussing the ways in which the speeches related with the maintenance of health and aesthetics invest in its improvement. Therefore, we used the Caderno Vida, a weekly insert of Zero Hora, for we understand it as owner of a proper speech that has the power of subjectivate people The analysis is part of Cultural Studies and it is based on the ideas of Michel Foucault. The methodological strategy used was the speech analysis of subjects about body care. The periodical questions its readers using speeches that point to beauty health and success The constructed categories were: how is the ideal body, what to do to have such body and why we must have this body Balanced feeding, practice of regular physical activities and the accomplishment of plastic surgeries are recommendations recurrently found in weekly inserts. PMID:19653558

  13. Modules over principal ideal rings

    E-print Network

    Vieaux, Jules Bellin

    1957-01-01

    - Then rlxl + r2 x 2 +. . . + rkxk = 0 where some choice of notation, we may suppose that rl g 0 ~ 4 r x = -r. -x -. . . - z' x = (-z )x +. . . + (-z )x 1 1 2 2 ''' k k 2 2 '' k k' so that xl is linearly dependent on x-, . . . , x . Now, without y..., we obtain an ascending chain of ideals (al'a2 al'a2'a3 c , ~ . or dl (d2 c ''' Hy Lemma 1, 6, this chain terminates in an 1deal (d&) (ai&a2 ~ ~ aH) and dH g c ~ f ip 2p l 5 Il. NODULES DEFINITION 2. 1. A left module 1s a commutative group M...

  14. The quantum mechanics of ion-enhanced field emission and how it influences microscale gas breakdown

    SciTech Connect

    Li, Yingjie [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Go, David B., E-mail: dgo@nd.edu [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2014-09-14

    The presence of a positive gas ion can enhance cold electron field emission by deforming the potential barrier and increasing the tunneling probability of electrons—a process known as ion-enhanced field emission. In microscale gas discharges, ion-enhanced field emission produces additional emission from the cathode and effectively reduces the voltage required to breakdown a gaseous medium at the microscale (<10 ?m). In this work, we enhance classic field emission theory by determining the impact of a gaseous ion on electron tunneling and compute the effect of ion-enhanced field emission on the breakdown voltage. We reveal that the current density for ion-enhanced field emission retains the same scaling as vacuum cold field emission and that this leads to deviations from traditional breakdown theory at microscale dimensions.

  15. Quantum-chemical modeling of boron and noble gas dopants in silicon

    NASA Technical Reports Server (NTRS)

    Aronowitz, S.

    1983-01-01

    The electron effects of the presence of boron and noble gas dopants in a model silicon lattice were investigated using a self-consistent charge extended Hueckel program. The extent of electronic interaction of the noble gas with the lattice is given by: Kr greater than Ar greater than Ne. Theoretically, boron diffusion in the presence of neon, argon or krypton was examined using a self-consistent charge extended Hueckel program. The net energy of interaction between boron and neon is strongly repulsive while argon-boron exhibits a region of relative stability; krypton exhibits behavior similar to argon though no region of stability was found for the range of separations used in the calculations. Finally, it is noted, from the relative energy of the topmost filled molecular orbital associated with boron (in an interstitial position), that activation of the boron does not require boron movement but can be accomplished by indirect transitions.

  16. Quantum Cascade Laser-Based Photoacoustic Sensor for Trace Detection of Formaldehyde Gas

    PubMed Central

    Elia, Angela; Di Franco, Cinzia; Spagnolo, Vincenzo; Lugarà, Pietro Mario; Scamarcio, Gaetano

    2009-01-01

    We report on the development of a photoacoustic sensor for the detection of formaldehyde (CH2O) using a thermoelectrically cooled distributed-feedback quantum cascade laser operating in pulsed mode at 5.6 ?m. A resonant photoacoustic cell, equipped with four electret microphones, is excited in its first longitudinal mode at 1,380 Hz. The absorption line at 1,778.9 cm?1 is selected for CH2O detection. A detection limit of 150 parts per billion in volume in nitrogen is achieved using a 10 seconds time constant and 4 mW laser power. Measurements in ambient air will require water vapour filters. PMID:22574040

  17. Quantum oscillations in a two-dimensional electron gas in black phosphorus thin films.

    PubMed

    Li, Likai; Ye, Guo Jun; Tran, Vy; Fei, Ruixiang; Chen, Guorui; Wang, Huichao; Wang, Jian; Watanabe, Kenji; Taniguchi, Takashi; Yang, Li; Chen, Xian Hui; Zhang, Yuanbo

    2015-07-01

    For decades, two-dimensional electron gases (2DEG) have allowed important experimental discoveries and conceptual developments in condensed-matter physics. When combined with the unique electronic properties of two-dimensional crystals, they allow rich physical phenomena to be probed at the quantum level. Here, we create a 2DEG in black phosphorus-a recently added member of the two-dimensional atomic crystal family-using a gate electric field. The black phosphorus film hosting the 2DEG is placed on a hexagonal boron nitride substrate. The resulting high carrier mobility in the 2DEG allows the observation of quantum oscillations. The temperature and magnetic field dependence of these oscillations yields crucial information about the system, such as cyclotron mass and lifetime of its charge carriers. Our results, coupled with the fact that black phosphorus possesses anisotropic energy bands with a tunable, direct bandgap, distinguish black phosphorus 2DEG as a system with unique electronic and optoelectronic properties. PMID:25984835

  18. C-C stretching Raman spectra and stabilities of hydrocarbon molecules in natural gas hydrates: a quantum chemical study.

    PubMed

    Liu, Yuan; Ojamäe, Lars

    2014-12-11

    The presence of specific hydrocarbon gas molecules in various types of water cavities in natural gas hydrates (NGHs) are governed by the relative stabilities of these encapsulated guest molecule-water cavity combinations. Using molecular quantum chemical dispersion-corrected hybrid density functional computations, the interaction (?E(host--guest)) and cohesive energies (?E(coh)), enthalpies, and Gibbs free energies for the complexes of host water cages and hydrocarbon guest molecules are calculated at the ?B97X-D/6-311++G(2d,2p) level of theory. The zero-point energy effect of ?E(host-guest) and ?E(coh) is found to be quite substantial. The energetically optimal host-guest combinations for seven hydrocarbon gas molecules (CH4, C2H6, C3H6, C3H8, C4H8, i-C4H10, and n-C4H10) and various water cavities (D, ID, T, P, H, and I) in NGHs are found to be CH4@D, C2H6@T, C3H6@T, C3H8@T, C4H8@T/P/H, i-C4H10@H, and n-C4H10@H, as the largest cohesive energy magnitudes will be obtained with these host-guest combinations. The stabilities of various water cavities enclosing hydrocarbon molecules are evaluated from the computed cohesive Gibbs free energies: CH4 prefers to be trapped in a ID cage; C2H6 prefer T cages; C3H6 and C3H8 prefer T and H cages; C4H8 and i-C4H10 prefer H cages; and n-C4H10 prefer I cages. The vibrational frequencies and Raman intensities of the C-C stretching vibrational modes for these seven hydrocarbon molecules enclosed in each water cavity are computed. A blue shift results after the guest molecule is trapped from gas phase into various water cages due to the host-guest interactions between the water cage and hydrocarbon molecule. The frequency shifts to the red as the radius of water cages increases. The model calculations support the view that C-C stretching vibrations of hydrocarbon molecules in the water cavities can be used as a tool to identify the types of crystal phases and guest molecules in NGHs. PMID:25406092

  19. Equation of state of a weakly interacting two-dimensional Bose gas studied at zero temperature by means of quantum Monte Carlo methods

    SciTech Connect

    Astrakharchik, G. E.; Boronat, J.; Casulleras, J. [Departament de Fisica i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain); Kurbakov, I. L.; Lozovik, Yu. E. [Institute of Spectroscopy, 142190 Troitsk, Moscow Region (Russian Federation)

    2009-05-15

    The equation of state of a weakly interacting two-dimensional Bose gas is studied at zero temperature by means of quantum Monte Carlo methods. Going down to as low densities as na{sup 2}{proportional_to}10{sup -100} permits us to obtain agreement on beyond mean-field level between predictions of perturbative methods and direct many-body numerical simulation, thus providing an answer to the fundamental question of the equation of state of a two-dimensional dilute Bose gas in the universal regime (i.e., entirely described by the gas parameter na{sup 2}). We also show that the measure of the frequency of a breathing collective oscillation in a trap at very low densities can be used to test the universal equation of state of a two-dimensional Bose gas.

  20. Thermal Casimir effect in ideal metal rectangular boxes

    E-print Network

    B. Geyer; G. L. Klimchitskaya; V. M. Mostepanenko

    2008-08-27

    The thermal Casimir effect in ideal metal rectangular boxes is considered using the method of zeta functional regularization. The renormalization procedure is suggested which provides the finite expression for the Casimir free energy in any restricted quantization volume. This expression satisfies the classical limit at high temperature and leads to zero thermal Casimir force for systems with infinite characteristic dimensions. In the case of two parallel ideal metal planes the results, as derived previously using thermal quantum field theory in Matsubara formulation and other methods, are reproduced starting from the obtained expression. It is shown that for rectangular boxes the temperature-dependent contribution to the electromagnetic Casimir force can be both positive and negative depending on side lengths. The numerical computations of the scalar and electromagnetic Casimir free energy and force are performed for cubes

  1. Steady states of a microwave-irradiated quantum-Hall gas.

    PubMed

    Auerbach, Assa; Finkler, Ilya; Halperin, Bertrand I; Yacoby, Amir

    2005-05-20

    We consider effects of a long-wavelength disorder potential on the zero conductance state (ZCS) of the microwave-irradiated 2D electron gas. Assuming a uniform Hall conductivity, we construct a Lyapunov functional and derive stability conditions on the domain structure of the photogenerated fields. We solve the resulting equations for a general one-dimensional and certain two-dimensional disorder potentials, and find nonzero conductances, photovoltages, and circulating dissipative currents. In contrast, weak white-noise disorder does not destroy the ZCS, but induces mesoscopic current fluctuations. PMID:16090195

  2. Quantum dynamics of an excited alkali atom in a noble gas cluster: lithium attached to a helium cluster.

    PubMed

    Pacheco, Alexander B; Thorndyke, Brian; Reyes, Andrés; Micha, David A

    2007-12-28

    An alkali atom-noble gas cluster system is considered as a model for solvation effects in optical spectra, within a quantum-classical description based on the density operator of a many-atom system and its partial Wigner transform. This leads to an eikonal-time-dependent molecular orbital treatment suitable for a time-dependent description of the coupling of light emission and atom dynamics in terms of the time-dependent electric dipole of the whole system. As an application, we consider an optically excited lithium atom as the dopant in a helium cluster at 0.5 K. We describe the motions of the excited Li atom interacting with a cluster of He atoms and calculate the time-dependent electric dipole of the Li-He(99) system during the dynamics. The electronic Hamiltonian is taken as a sum of three-body Li-He diatomic potentials including electronic polarization and repulsion, with l-dependent atomic pseudopotentials for Li and He, while we use a modified pair potential for He-He. The calculations involve the coupling of 12 quantum states with 300 classical degrees of freedom. We present results for the dynamics and spectra of a Li atom interacting with a model cluster surface of He atoms and also interacting with a droplet of He. We have found that the Li atom is attracted or repulsed from the He surface, depending on the orientation of its 2p orbitals. The spectra and dynamics of Li inside and at the surface of a cluster are found to be strongly dependent on its electronic states, its velocity direction, and whether light is present during emission or not. PMID:18163688

  3. Trace Gas Measurements with a Multiplexed Intra-Pulse Quantum Cascade Laser Spectrometer

    NASA Astrophysics Data System (ADS)

    Wilson, D.; Duxbury, G.; Langford, N.

    2012-06-01

    Quantitative measurements of the equilibrium concentrations of nitrogen dioxide and dinitrogen-tetroxide have been made using a multiplexed intra-pulse QC laser spectrometer. The measurements were made using long duration pulses from 7.84 and 7.46 micron Quantum Cascade (QC) lasers in the QC laser spectrometer. For double pulse operation the pulse signal from the first laser controller is used to generate a delayed optical pulse from the second laser by using a digital delay pulse generator.This allows two spectra to be recorded sequentially using the 2 Gs high speed digitiser. The spectra are compared with the dimer spectra recorded by J Vander Auwera and his colleagues using using a high resolution Fourier transform spectrometer at the Free University of Brussels.

  4. Half-quantum vortex molecules in a binary dipolar Bose gas.

    PubMed

    Shirley, Wilbur E; Anderson, Brandon M; Clark, Charles W; Wilson, Ryan M

    2014-10-17

    We study the ground state phases of a rotating two-component, or binary, Bose-Einstein condensate, wherein one component possesses a large permanent magnetic dipole moment. A variety of nontrivial phases emerge in this system, including a half-quantum vortex (HQV) chain phase and a HQV molecule phase, where HQVs bind at short distances. We attribute these phases to the development of a minimum in the HQV interaction potential, which emerges without coherent coupling or attractive interactions between the components. Thus, we show that the presence of dipolar interactions in this system provides a unique mechanism for the formation of HQV molecules and results in a rich ground state phase diagram. PMID:25361261

  5. Plasmon response of a quantum-confined electron gas probed by core-level photoemission

    SciTech Connect

    Ozer, Mustafa M [ORNL; Moon, Eun Ju [University of Tennessee, Knoxville (UTK); Eguiluz, Adolfo G [ORNL; Weitering, Harm H [ORNL

    2011-01-01

    We demonstrate the existence of quantized 'bulk' plasmons in ultrathin magnesium films on Si(111) by analyzing plasmon-loss satellites in core-level photoemission spectra, recorded as a function of the film thickness d. Remarkably, the plasmon energy is shown to vary as 1/d{sup 2} all the way down to three atomic layers. The loss spectra are dominated by the n=1 and n=2 normal modes, consistent with the excitation of plasmons involving quantized electronic subbands. With decreasing film thickness, spectral weight is gradually transferred from the plasmon modes to the low-energy single-particle excitations. These results represent striking manifestations of the role of quantum confinement on plasmon resonances in precisely controlled nanostructures.

  6. Variational mixed quantum/semiclassical simulation of dihalogen guest and rare-gas solid host dynamics

    NASA Astrophysics Data System (ADS)

    Cheng, Xiaolu; Cina, Jeffrey A.

    2014-07-01

    A variational mixed quantum-semiclassical theory for the internal nuclear dynamics of a small molecule and the induced small-amplitude coherent motion of a low-temperature host medium is developed, tested, and used to simulate the temporal evolution of nonstationary states of the internal molecular and surrounding medium degrees of freedom. In this theory, termed the Fixed Vibrational Basis/Gaussian Bath (FVB/GB) method, the system is treated fully quantum mechanically while Gaussian wave packets are used for the bath degrees of freedom. An approximate time-dependent wave function of the entire model is obtained instead of just a reduced system density matrix, so the theory enables the analysis of the entangled system and bath dynamics that ensues following initial displacement of the internal-molecular (system) coordinate from its equilibrium position. The norm- and energy-conserving properties of the propagation of our trial wave function are natural consequences of the Dirac-Frenkel-McLachlan variational principle. The variational approach also stabilizes the time evolution in comparison to the same ansatz propagated under a previously employed locally quadratic approximation to the bath potential and system-bath interaction terms in the bath-parameter equations of motion. Dynamics calculations are carried out for molecular iodine in a 2D krypton lattice that reveal both the time-course of vibrational decoherence and the details of host-atom motion accompanying energy dissipation and dephasing. This work sets the stage for the comprehensive simulation of ultrafast time-resolved optical experiments on small molecules in low-temperature solids.

  7. LATTICE GAS SUPERFLUID

    Microsoft Academic Search

    JEFFREY YEPEZ

    A quantum computer, with controlled decoherence, constructed out of a lattice based array of qubits undergoing a particular local and unitary evolution is eectively a bose condensate. Presented is a coupled lattice gas system, a quantum lattice gas and a classical lattice gas in mutual contact through \\\\external\\

  8. Repulsive atomic Fermi gas with Rashba spin-orbit coupling: A quantum Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Ambrosetti, Alberto; Silvestrelli, Pier Luigi; Pederiva, Francesco; Mitas, Lubos; Toigo, Flavio

    2015-05-01

    Thanks to the recent experimental realization and control of artificial gauge fields, spin-orbit (SO) couplings are witnessing an ever increasing interest in the field of cold atoms. However, predicting their effect on spin polarization and energetic properties of interacting systems is a major challenge, due to the complex interplay between spin and position dynamics. In this work we exploit the diffusion Monte Carlo algorithm to compute energetic and polarization properties of a three-dimensional repulsive Fermi gas in the presence of Rashba spin-orbit coupling. We find that SO effects tend to contrast the spin alignment induced by the exchange interaction, slightly shifting the onset of the Stoner instability towards larger values of the scattering length. In addition, polarization and energy properties of the system can be tuned trough a combined control of the repulsive interaction and Rashba coupling.

  9. Sensitive detection of NO in exhaust gas with a frequency-modulated, distributed-feedback, quantum-cascade laser

    NASA Astrophysics Data System (ADS)

    Weber, W. H.; Remillard, J. T.; Uy, D.; Gmachl, C.; Capasso, F.; Hutchinson, A. L.; Sivco, D. L.; Baillargeon, J. N.; Cho, A. Y.

    2001-03-01

    Measurements of NO concentrations at sub-ppm levels in vehicle exhaust are needed for emission certification of future ultra-low emission vehicles. We demonstrate a laser-based system that can measure NO at a few ppb in exhaust gas. A distributed-feedback quantum cascade laser operating cw at 90 K is frequency modulated at f = 1 kHz and locked to the center of a transition at ~ 1921 cm-1 in the fundamental band of NO. Part of the beam is passed through a reference cell with 0.5% NO/N2 and then onto a detector whose demodulated signal at 1f is fed back to control the laser frequency. The rest of the beam passes through a long-pass (100 m) cell and onto a detector whose demodulated signal at 2f directly measures the NO concentration. Doppler broadening, pressure broadening, and unresolved ? doubling combine to yield a pressure for optimum sensitivity of 100 Torr and a modulation amplitude of ~ 750 MHz. The rms error (1?) in the 2f signal corresponds to an uncertainty of ± 1 ppb, but systematic errors associated with adsorption and desorption of NO on the cell walls and plumbing can greatly exceed this random error.

  10. Cross-sections and quantum yields for the atmospheric photolysis of the potent greenhouse gas nitrogen trifluoride

    NASA Astrophysics Data System (ADS)

    Dillon, Terry J.; Horowitz, Abraham; Crowley, John N.

    2010-03-01

    Although NF 3, a trace gas of purely anthropogenic origin with a large global warming potential is accumulating in the Earth's atmosphere, little photochemical data exists from which to calculate its atmospheric removal rate. In this study, photodissociation quantum yields, ?1, were derived following 193.3 nm laser photolysis of NF 3, and quantitative conversion of the F-atom photoproducts to OH, which was detected by laser induced fluorescence. Values of ?1( P, T) = (1.03 ± 0.05) were determined at pressures between 28 and 100 mBar of He or N 2 and at either room temperature or 255 K. Absorption cross-sections, ?, obtained between 184 and 226 nm were combined with the values of ?1( P, T) to confirm a long (?700 year) photolysis lifetime for NF 3. No evidence for reaction of OH with NF 3 was found, indicating that this process makes little or no contribution to NF 3 removal from the atmosphere. These results underpin recent calculations of an NF 3 atmospheric lifetime ? ? 550 years, largely controlled by photolysis in the stratosphere. In the course of this work the rate coefficient k2(298 K) = (1.3 ± 0.2) × 10 -11 cm 3 molecule -1 s -1 was obtained for the reaction F + H 2O.

  11. Gas Phase Photoacoustic Spectroscopy in the long-wave IR using Quartz Tuning Forks and Amplitude Modulated Quantum Cascade Lasers

    SciTech Connect

    Wojcik, Michael D.; Phillips, Mark C.; Cannon, Bret D.

    2006-12-31

    A paper to accompany a 20 minute talk about the progress of a DARPA funded project called LPAS. ABSTRACT: We demonstrate the performance of a novel long-wave infrared photoacoustic laser absorbance spectrometer for gas-phase species using an amplitude modulated (AM) quantum cascade (QC) laser and a quartz tuning fork microphone. Photoacoustic signal was generated by focusing the output of a Fabry-Perot QC laser operating at 8.41 micron between the legs of a quartz tuning fork which served as a transducer for the transient acoustic pressure wave. The QC laser was modulated at the resonant frequency of the tuning fork (32.8 kHz). This sensor was calibrated using the infrared absorber Freon-134a by performing a simultanious absorption measurement using a 35 cm absorption cell. The NEAS of this instrument was determined to be 2 x 10^-8 W cm^-1 /Hz^1/2 and the fundamental sensitivity of this technique is limited by the noise floor of the tuning fork itself.

  12. [A trace gas sensor using mid-infrared quantum cascaded laser at 4.8 microm to detect carbon monoxide].

    PubMed

    Chen, Chen; Wang, Biao; Li, Chun-Guang; Li, Jian; Wang, Yi-Ding

    2014-03-01

    Presented in the present paper is a compact instrument developed for rapid, sensitive and continuous monitoring of trace gases in air, with results shown for carbon monoxide concentration. This instrument takes advantage of recent technology in mid-infrared quantum cascaded laser (QCL) operating at 4.8 microm and mercury cadmium telluride (HgCdTe) mid-infrared (MIR) detector, combing MIR multipass herriott cell with 76 m absorption path length to obtain low detection sensitivity down to 50 nmol x mol(-1) level in 4 s acquisition time. Meanwhile, in order to eliminate the instability induced by electrically modulated light source and effectively improve detection limit of the instrument, an optical structure with dual channel path was designed which is based on differential optical absorption spectroscopy method. The experimental results show that the instrument integrated with gas concentration inversion algorithm can be applied to in-situ measurements of trace gases without calibration. Additionally, operator could substitute a QCL operating at a different wavelength to measure other gases. PMID:25208424

  13. [A trace methane gas sensor using mid-infrared quantum cascaded laser at 7.5 microm].

    PubMed

    Chen, Chen; Dang, Jing-Min; Huang, Jian-Qiang; Yang, Yue; Wang, Yi-Ding

    2012-11-01

    Presented is a compact instrument developed for in situ high-stable and sensitive continuous measurement of trace gases in air, with results shown for ambient methane (CH4) concentration accurate, real-time and in-situ. This instrument takes advantage of recent technology in thermoelectrically cooling (TEC) pulsed Fabry-Perot (FP) quantum cascaded laser (QCL) driving in a pulse mode operating at 7.5 microm ambient temperature to cover a fundamental spectral absorption band near v4 of CH4. A high quality Liquid Nitrogen (LN) cooled Mercury Cadmium Telluride (HgCdTe) mid-infrared (MIR) detector is used along with a total reflection coated gold ellipsoid mirror offering 20 cm single pass optical absorption in an open-path cell to achieve stability of 5.2 x 10(-3) under experimental condition of 200 micromol x mol(-1) measured ambient CH4. The instrument integrated software via time discriminating electronics technology to control QCL provides continuous quantitative trace gas measurements without calibration. The results show that the instrument can be applied to field measurements of gases of environmental concern. Additional, operator could substitute a QCL operating at a different wavelength to measure other gases. PMID:23387197

  14. The mass and energy of a vapor bubble in a turbulent ideal fluid

    E-print Network

    Valery P. Dmitriyev

    2006-02-22

    The mass of a bubble in a fluid can be taken as the mass of the vapor in it. The self-energy of the bubble is defined as the work performed against the pressure of the fluid in order to create the bubble. Taking the vapor to be an ideal gas the relationship between the self-energy, the mass of the bubble and the speed of the perturbation wave in a turbulent ideal fluid can be obtained.

  15. Modelling thermal fluctuations in non-ideal fluids with the lattice Boltzmann method.

    PubMed

    Gross, M; Adhikari, R; Cates, M E; Varnik, F

    2011-06-13

    Recently, we proposed a theoretical framework to include thermal fluctuations into the Lattice Boltzmann (LB) method for non-ideal fluids. Here, we apply a variant thereof to a certain class of force-based non-ideal fluid LB models. We find that ideal-gas-like noise is an exact result of the fluctuation-dissipation theorem in the hydrodynamic regime. It is shown that satisfactory equilibration of the density and fluid momentum can be obtained in a simulation over a wide range of length scales. PMID:21536574

  16. Kinetics and mechanism of the beta-alanine + OH gas phase reaction: a quantum mechanical approach.

    PubMed

    Cruz-Torres, Armando; Galano, Annia; Alvarez-Idaboy, J Raúl

    2006-01-14

    The OH hydrogen abstraction reaction from beta-alanine has been studied using the BHandHLYP hybrid HF-density functional and 6-311G(d,p) basis sets. The energies have been improved by single point calculations at the CCSD(T)/6-311G(d,p) level of theory. The structures of the different stationary points are discussed. Reaction profiles are modeled including the formation of pre-reactive and product complexes. Negative net activation energy is obtained for the overall reaction. A complex mechanism is proposed, and the rate coefficients are calculated using transition state theory over the temperature range of 250-400 K. The rate coefficients are proposed for the first time and it was found that in the gas phase the hydrogen abstraction occurs mainly from the CH(2) group next to the amino end. The following expressions, in cm(3) mol(-1) s(-1), are obtained for the overall rate constants, at 250-400 and 290-310 K, respectively: k(250-400)= 2.36 x 10(-12) exp(340/T), and k(290-310)= 1.296 x 10(-12) exp(743/T). The three parameter expression that best describes the studied reaction is k(250-400)= 1.01 x 10(-21)T(3.09) exp(1374/T). The beta-alanine + OH reaction was found to be 1.5 times faster than the alpha-alanine + OH reaction. PMID:16482271

  17. Towards enhancing two-dimensional electron gas quantum confinement effects in perovskite oxide heterostructures

    NASA Astrophysics Data System (ADS)

    Nazir, Safdar; Behtash, Maziar; Yang, Kesong

    2015-03-01

    We explore the possibility of achieving highly confined two-dimensional electron gas (2DEG) within one single atomic layer through a comprehensive comparison study on three prototypical perovskite heterostructures, LaAlO3/ATiO3 (A = Ca, Sr, and Ba), using first-principles electronic structure calculations. We predict that the heterostructure LaAlO3/BaTiO3 has a highly confined 2DEG within a single atomic layer of the substrate BaTiO3, and exhibits relatively higher interfacial charge carrier density and larger magnetic moments than the well-known LaAlO3/SrTiO3 system. The long Ti-O bond length in the ab-plane of the LaAlO3/BaTiO3 heterostructure is responsible for the superior charge confinement. We propose BaTiO3 as an exceptional substrate material for 2DEG systems with potentially superior properties.

  18. Unique irredundant intersections of completely irreducible ideals

    E-print Network

    2005-02-25

    Feb 25, 2005 ... with Laszlo Fuchs in the articles [2], [3], [4] and [5]. We would like to .... (iv) For every proper ideal A of R, the set Z(A) of Zariski-Samuel associated. primes of A is ... By (vi) there is a collection {Ni : i ? I2} of maximal ideals such.

  19. A Practical Application of the IDEAL Model

    Microsoft Academic Search

    Valentine Casey; Ita Richardson

    2002-01-01

    The focus of this paper is to outline the experience of a European based software organization utilizing the IDEAL model, while implementing a tailored Capability Maturity Model (CMM) software process improvement program. The goal was to achieve process improvement rather than a specific CMM maturity level. In doing this, the IDEAL model was extensively researched and employed. The benefits and

  20. COMPUTING CANONICAL REPRESENTATIVES OF REGULAR DIFFERENTIAL IDEALS

    E-print Network

    Paris-Sud XI, Université de

    differential ring defined by a regular differential ideal. Keywords: differential algebra, RosenfeldCOMPUTING CANONICAL REPRESENTATIVES OF REGULAR DIFFERENTIAL IDEALS Franc¸ois Boulier Universit algebraic and differential characteristic sets. The third one is theoretical as well as practical: an al

  1. Ideals and flexibility in close relationships

    E-print Network

    Campbell, Lorne John

    1998-01-01

    and their ideal partner on three dimensions (warmth/trustworthiness, vitality/attractiveness, status/resources), report how likely they were to be satisfied with a person who does not match their ideals, and to rate how closely their current dating partner matched...

  2. Quantum friction

    E-print Network

    R. Tsekov

    2015-06-06

    The Brownian motion of a light quantum particle in a heavy classical gas is theoretically described and a new expression for the friction coefficient is obtained for arbitrary temperature. At zero temperature it equals to the de Broglie momentum of the mean free path divided by the mean free path. Alternatively, the corresponding mobility of the quantum particle in the classical gas is equal to the square of the mean free path divided by the Planck constant. The Brownian motion of a quantum particle in a quantum environment is also discussed.

  3. Kirkwood-Buff integrals for ideal solutions.

    PubMed

    Ploetz, Elizabeth A; Bentenitis, Nikolaos; Smith, Paul E

    2010-04-28

    The Kirkwood-Buff (KB) theory of solutions is a rigorous theory of solution mixtures which relates the molecular distributions between the solution components to the thermodynamic properties of the mixture. Ideal solutions represent a useful reference for understanding the properties of real solutions. Here, we derive expressions for the KB integrals, the central components of KB theory, in ideal solutions of any number of components corresponding to the three main concentration scales. The results are illustrated by use of molecular dynamics simulations for two binary solutions mixtures, benzene with toluene, and methanethiol with dimethylsulfide, which closely approach ideal behavior, and a binary mixture of benzene and methanol which is nonideal. Simulations of a quaternary mixture containing benzene, toluene, methanethiol, and dimethylsulfide suggest this system displays ideal behavior and that ideal behavior is not limited to mixtures containing a small number of components. PMID:20441282

  4. Atmospheric trace gas measurements using a dual quantum-cascade laser mid-infrared absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Jimenez, Rodrigo; Herndon, Scott; Shorter, Joanne H.; Nelson, David D.; McManus, J. B.; Zahniser, Mark S.

    2005-04-01

    We present an overview of the dual QC laser spectrometer developed at Aerodyne Research and various examples of its application for atmospheric trace gas detection. The instrument incorporates two pulsed QC lasers, a compact 76-m (or 56-m) multipass absorption cell, a dual HgCdTe detector, and a sophisticated signal generation, data acquisition and processing system. Recent findings and hardware innovations are highlighted. Our results show that the precision and minimal detectable absorbance obtainable with pulsed QC lasers are comparable to those achieved with cryogenically cooled CW Pb-salt lasers in spite of the broader laser linewidths inherent to pulsed operation. This is demonstrated through in situ measurements of several trace gases, including methane, nitrous oxide, carbon monoxide, formaldehyde, formic acid, nitrous acid and ethylene. Recent measurements of HCHO and HCOOH on board a NOAA aircraft are presented. The precision, stability and intrinsic accuracy of the instrument were assessed through inter-comparisons measuring CH4 and CO. These measurements were made either comparing two QC lasers sweeping over different transitions or comparing the dual QCL spectrometer and a standard instrument (NDIR CO). The absorbance precision achieved is typically 2x10-5 Hz-1/2. For long-lived species, such as CH4 and N2O, this implies 1-Hz fractional precisions of 0.1% or better, which fulfill the requirement for meaningful measurements from aircraft platforms. Spectroscopically derived mixing ratios are accurate within 5% or better. The spectrometer is equipped to perform automatic, periodic calibrations with zero and span gases whenever higher accuracy is required.

  5. Forging the Ideal Liberal LearningForging the Ideal Liberal Learning (Goals of Education)

    E-print Network

    Miyashita, Yasushi

    Active Learning of English for Science Students 3CWPCritical Writing Program 4 New Textbooks for Life1 Forging the Ideal Liberal LearningForging the Ideal Liberal Learning (Goals of Education the Ideal Liberal Learning 1 (Structuring of Knowledge) 2005 GFK lectures since 2005 #12;3 GFK

  6. Quantum chemical study of trimolecular reaction mechanism between nitric oxide and oxygen in the gas phase.

    PubMed

    Gadzhiev, Oleg B; Ignatov, Stanislav K; Razuvaev, Alexei G; Masunov, Artëm E

    2009-08-13

    Singlet and triplet potential energy surfaces of the reaction between molecular oxygen and two nitric oxide(II) molecules were studied by quantum chemical methods (coupled cluster, CASSCF, and density functional theory: B3LYP, TPSS, VSXC, BP86, PBE, B2-PLYP, B2K-PLYP). Elementary steps involving various N2O4 isomers (cyclic, cis-cis-, cis-trans-, trans-trans-ONOONO, cis- and trans-ONONO2, O2NNO2) were considered, as well as weakly bound molecular clusters preceding formation of O2NNO2, and Coupe-type quasi-aromatic hexagonal ring intermediate NO2.O2N. We found that activation energy strongly depends on the conformation of ONOONO peroxide, which is formed barrierlessly. The best agreements with experimental values were achieved by the B3LYP functional with aug-pc3 basis set. The lowest transition state (TS) energies correspond to the following reaction channel: 2NO + O2 (0 kJ/mol) --> cis-cis-ONOONO (-45 kJ/mol) --> TS1 --> NO2.O2N (-90 kJ/mol) --> TS2 --> cis-ONONO2 (-133 kJ/mol)--> TS3 --> trans-ONONO2 (-144 kJ/mol) --> TS4 --> O2NNO2 (-193 kJ/mol). A valley ridge inflection (VRI) point is located on the minimum energy path (MEP) connecting NO2.O2N and cis-ONONO2. The energy landscape between NO2.O2N and CC-TS2 can be classified as a downhill valley-pitchfork VRI bifurcation according to a recent classification of bifurcation events [Quapp, W. J. Mol. Struct. 2004, 95, 695-696]. The first and second transition states correspond to barrier heights of 10.6 and 37.0 kJ/mol, respectively. These values lead to the negative temperature dependence of the rate constant. The apparent activation enthalpy of the overall reaction was calculated to be Delta(r)H(0) = -4.5 kJ/mol, in perfect agreement with the experimental value. PMID:19610649

  7. Converging cylindrical shocks in ideal magnetohydrodynamics

    SciTech Connect

    Pullin, D. I. [Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, California 91125 (United States); Mostert, W.; Wheatley, V. [School of Mechanical and Mining Engineering, University of Queensland, Queensland 4072 (Australia); Samtaney, R. [Mechanical Engineering, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2014-09-15

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=?(?{sub 0}/p{sub 0}) I/(2 ?) where I is the current, ?{sub 0} is the permeability, and p{sub 0} is the pressure ahead of the shock. For shocks initiated at r ? R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then slows the shock Mach number growth producing a maximum followed by monotonic reduction towards magnetosonic conditions, even as the shock accelerates toward the axis. A parameter space of initial shock Mach number at a given radius is explored and the implications of the present results for inertial confinement fusion are discussed.

  8. Converging cylindrical shocks in ideal magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, R.

    2014-09-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=sqrt{? _0/p_0} I/(2 ? ) where I is the current, ?0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ? R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then slows the shock Mach number growth producing a maximum followed by monotonic reduction towards magnetosonic conditions, even as the shock accelerates toward the axis. A parameter space of initial shock Mach number at a given radius is explored and the implications of the present results for inertial confinement fusion are discussed.

  9. Ideal Gas of Strings and QCD at Hadronic Scales

    E-print Network

    Chung-I Tan

    1993-01-08

    By using lessons learned from modern string studies, we show how interesting non-perturbative features of QCD can be learned from future heavy ion collisions even if the deconfinement density is not reached.

  10. Statistical problem of ideal gas in general 2-dimensional regions

    E-print Network

    Ci Song; Wen-Du Li; Pardon Mwansa; Ping Zhang

    2014-12-19

    In this paper, based on the conformal mapping method and the perturbation theory, we develop a method to solve the statistical problem within general 2-dimensional regions. We consider some examples and the numerical results and fitting results are given. We also give the thermodynamic quantities of the general 2-dimensional regions, and compare the thermodynamic quantities of the different regions.

  11. Statistical problem of ideal gas in general 2-dimensional regions

    E-print Network

    Song, Ci; Mwansa, Pardon; Zhang, Ping

    2015-01-01

    In this paper, based on the conformal mapping method and the perturbation theory, we develop a method to solve the statistical problem within general 2-dimensional regions. We consider some examples and the numerical results and fitting results are given. We also give the thermodynamic quantities of the general 2-dimensional regions, and compare the thermodynamic quantities of the different regions.

  12. Definition and Properties of Ideal Amorphous Solids

    NASA Astrophysics Data System (ADS)

    Stachurski, Zbigniew H.

    2003-04-01

    It is proposed that two ideal amorphous structures, typeI and typeII, based on maximally random jammed packing of spheres of equal size, form a distinct class of ideal amorphous solids. The ideal amorphous structures contain wide variations in local density, limited by the condition of solidity. Four distinct characteristics, based on statistical geometry and topology, are shown to define this class. Voronoi tessellations carried out on simulated cells of random packed spheres and amorphous polymers give a broad distribution of individual volumes, skewed, with a tail at the high volume end.

  13. Definition and properties of ideal amorphous solids.

    PubMed

    Stachurski, Zbigniew H

    2003-04-18

    It is proposed that two ideal amorphous structures, type I and type II, based on maximally random jammed packing of spheres of equal size, form a distinct class of ideal amorphous solids. The ideal amorphous structures contain wide variations in local density, limited by the condition of solidity. Four distinct characteristics, based on statistical geometry and topology, are shown to define this class. Voronoi tessellations carried out on simulated cells of random packed spheres and amorphous polymers give a broad distribution of individual volumes, skewed, with a tail at the high volume end. PMID:12732045

  14. Vortices in non-ideal dusty plasmas

    NASA Astrophysics Data System (ADS)

    Nebbat, E.; Annou, R.

    2011-11-01

    Nebbat and Annou (c.f.Ref.[1]) proposed a time dependent non-linear model that considers vortices as a consequence of an instability, and where the plasma is considered ideal. In this note, we propose another approach consisting of including the grain-grain interaction force it in the pressure term. The fluid is no longer considered ideal and the pressure term is to be modified accordingly to account for the non-ideality of the dust fluid. We choose a Van Der Waals equation of state. A comparison is conducted between both approaches.

  15. Predicting film genres with implicit ideals.

    PubMed

    Olney, Andrew McGregor

    2012-01-01

    We present a new approach to defining film genre based on implicit ideals. When viewers rate the likability of a film, they indirectly express their ideal of what a film should be. Across six studies we investigate the category structure that emerges from likability ratings and the category structure that emerges from the features of film. We further compare these data-driven category structures with human annotated film genres. We conclude that film genres are structured more around ideals than around features of film. This finding lends experimental support to the notion that film genres are set of shifting, fuzzy, and highly contextualized psychological categories. PMID:23423823

  16. Expansion of the Gibbs potential for quantum many-body systems: General formalism with applications to the spin glass and the weakly nonideal Bose gas

    NASA Astrophysics Data System (ADS)

    Plefka, T.

    2006-01-01

    For general quantum systems the power expansion of the Gibbs potential and consequently the power expansion of the self-energy is derived in terms of the interaction strength. Employing a generalization of the projector technique, a compact representation of the general terms of the expansion results. The general aspects of the approach are discussed with special emphasis on the effects characteristic for quantum systems. The expansion is systematic and leads directly to contributions beyond the mean field of all thermodynamic quantities. These features are explicitly demonstrated and illustrated for two nontrivial systems, the infinite-range quantum spin glass and the weakly interacting Bose gas. The Onsager terms of both systems are calculated, which represent the first beyond-mean-field contributions. For the spin glass Thouless-Anderson-Palmer-like equations are presented and discussed in the paramagnetic region. The investigation of the Bose gas leads to a beyond-mean-field thermodynamic description. At the Bose-Einstein condensation temperature complete agreement is found with the results presented recently by alternative techniques.

  17. Monomization of power Ideals and parking functions

    E-print Network

    Desjardins, Craig J. (Craig Jeffrey)

    2010-01-01

    A zonotopal algebra is the quotient of a polynomial ring by an ideal generated by powers of linear forms which are derived from a zonotope, or dually it's hyperplane arrangement. In the case that the hyperplane arrangement ...

  18. Fundamental thermodynamics of ideal absorption cycles

    Microsoft Academic Search

    Ron W James

    1997-01-01

    Starting from the representation of a real absorption refrigeration cycle on a temperature-entropy diagram, step-by-step idealisations of the binary mixture, together with the thermodynamic transformations are considered, in order to derive the ideal thermodynamic absorption cycle performance and temperature formulae. It is demonstrated that the ideal absorption cycle is the combination of a Carnot driving cycle with a reverse Carnot

  19. IDEALS OF RINGS OF DIFFERENTIAL OPERATORS ON

    Microsoft Academic Search

    YURI BEREST; OLEG CHALYKH

    Let X be a smooth affine irreducible curve overC, and let D = D(X) be the ring of global differential operators on X. In this paper, we give a geometric classification of left ideals in D and study the natural action of the Picard group of D on the space I(D) of isomorphism classes of such ideals. We recall that,

  20. The Wendell Berry ideal: harmony and wholeness 

    E-print Network

    Kutach, Douglas Neil

    1992-01-01

    THE WENDELL BERRY IDEAL: HARMONY AND WHOLENESS A Thesis by DOUGLAS NEIL KUTACH Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF ARTS August 1992 Major... Subject: Philosophy THE WENDELL BERRY IDEAL: HARMONY AND WHOLENESS A Thesis by DOUGLAS NEIL KUTACH Approved as to style and content by: Paul B. Thompson (Chair of Committee) Paul Theobald (Member) John McDermott (Member) Herman Sa kamp (Head...

  1. Ideal shrinking and expansion of discrete sequences

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.

    1986-01-01

    Ideal methods are described for shrinking or expanding a discrete sequence, image, or image sequence. The methods are ideal in the sense that they preserve the frequency spectrum of the input up to the Nyquist limit of the input or output, whichever is smaller. Fast implementations that make use of the discrete Fourier transform or the discrete Hartley transform are described. The techniques lead to a new multiresolution image pyramid.

  2. Sahaja: an Indian ideal of mental health.

    PubMed

    Neki, J S

    1975-02-01

    Sahaja is an Indian ideal of mental and spiritual health that has received special emphasis in the Sikh scriptures--especially, the Adi Granth. Since the concept of sahaja has long been associated with mystical thought and practice, its description has become shrouded in peculiar esoteric terminologies. It is the purpose of this communication to divest sahaja of its esoteric, mystic connotations and to redefine it as a mental health ideal in the context of contemporary conditions. PMID:1114187

  3. Guiding Center Equations for Ideal Magnetohydrodynamic Modes

    SciTech Connect

    Roscoe B. White

    2013-02-21

    Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through ?~B = ? X (? X B) however perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement ? are derived which perserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

  4. Guiding center equations for ideal magnetohydrodynamic modes

    SciTech Connect

    White, R. B. [Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)

    2013-04-15

    Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through {delta}B-vector={nabla} Multiplication-Sign ({xi}-vector Multiplication-Sign B-vector), however, perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories, the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement {xi}-vector are derived which preserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

  5. Efficient channels for the ideal observer

    NASA Astrophysics Data System (ADS)

    Park, Subok; Kupinski, Matthew A.; Clarkson, Eric; Barrett, Harrison H.

    2004-05-01

    For a signal-detection task, the Bayesian ideal observer is optimal among all observers because it incorporates all the statistical information of the raw data from an imaging system. The ideal observer test statistic, the likelihood ratio, is difficult to compute when uncertainties are present in backgrounds and signals. In this work, we propose a new approximation technique to estimate the likelihood ratio. This technique is a dimensionality-reduction scheme we will call the channelized-ideal observer (CIO). We can reduce the high-dimensional integrals of the ideal observer to the low-dimensional integrals of the CIO by applying a set of channels to the data. Lumpy backgrounds and circularly symmetric Gaussian signals are used for simulations studies. Laguerre-Gaussian (LG) channels have been shown to be useful for approximating ideal linear observers with these backgrounds and signals. For this reason, we choose to use LG channels for our data. The concept of efficient channels is introduced to closely approximate ideal-observer performance with the CIO for signal-known-exactly (SKE) detection tasks. Preliminary results using one to three LG channels show that the performance of the CIO is better than the channelized-Hotelling observer for the SKE detection tasks.

  6. The Statistical Mechanics of Ideal MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2003-01-01

    Turbulence is a universal, nonlinear phenomenon found in all energetic fluid and plasma motion. In particular. understanding magneto hydrodynamic (MHD) turbulence and incorporating its effects in the computation and prediction of the flow of ionized gases in space, for example, are great challenges that must be met if such computations and predictions are to be meaningful. Although a general solution to the "problem of turbulence" does not exist in closed form, numerical integrations allow us to explore the phase space of solutions for both ideal and dissipative flows. For homogeneous, incompressible turbulence, Fourier methods are appropriate, and phase space is defined by the Fourier coefficients of the physical fields. In the case of ideal MHD flows, a fairly robust statistical mechanics has been developed, in which the symmetry and ergodic properties of phase space is understood. A discussion of these properties will illuminate our principal discovery: Coherent structure and randomness co-exist in ideal MHD turbulence. For dissipative flows, as opposed to ideal flows, progress beyond the dimensional analysis of Kolmogorov has been difficult. Here, some possible future directions that draw on the ideal results will also be discussed. Our conclusion will be that while ideal turbulence is now well understood, real turbulence still presents great challenges.

  7. Quantum Lattice-Gas Algorithm for Quantum Turbulence - CAP Simulations on 12,288 Cores of Cray XT-5 Einstein at NAVO

    Microsoft Academic Search

    George Vahala; Jeffrey Yepez; Min Soe; Linda Vahala; Sean Ziegeler

    2009-01-01

    A novel unitary quantum lattice algorithm is developed to explore quantum turbulence. Because of its low memory requirements and its near perfect parallelization to the full 12,288 cores on the Cray XT5, simulations were run up to spatial grids of 5,7603. The Gross-Pitaevskii equation, which describes the ground state of a Bose Einstein condensate (BEC), is solved and it is

  8. Transport and Mobility Properties of Bulk Indium Nitride (InN) and a Two-Dimensional Electron Gas in an InGaN\\/GaN Quantum Well

    Microsoft Academic Search

    Z. Yarar; B. Ozdemir; M. Ozdemir

    2007-01-01

    We studied the transport and low-field mobility properties of bulk InN and a two-dimensional electron gas confined in an InGaN\\/GaN\\u000a quantum well with regard to various parameters such as well width and interface roughness as a function of temperature. Since\\u000a new material parameters for InN have been suggested by recent studies, the traditionally accepted and recently published parameter\\u000a values for

  9. Quantum effects in the case of (6)Li+ and (7)Li+ ions evolving in a neutral (6)Li gas at a wide range of temperatures.

    PubMed

    Bouchelaghem, F; Bouledroua, M

    2014-02-01

    This work deals with the quantum-mechanical calculation of the temperature-dependent mobility of ionic lithium atoms diffusing in their parent gas. The computation of the quantal phase shifts in connection with the gerade and ungerade potential-energy curves, through which Li(+) approaches Li(2s), leads to the computation of the charge-transfer and diffusion cross sections. The behavior of the coefficients of diffusion and mobility with temperature is also examined. Throughout this work, the isotopic effects in the (6)Li(+)-(6)Li and (7)Li(+)-(6)Li collisions are emphasized. PMID:24326775

  10. Quantum oscillations and subband properties of the two-dimensional electron gas at the LaAlO{sub 3}/SrTiO{sub 3} interface

    SciTech Connect

    McCollam, A., E-mail: A.McCollam@science.ru.nl; Guduru, V. K.; Zeitler, U.; Maan, J. C. [High Field Magnet Laboratory and Institute for Molecules and Materials, Radboud University Nijmegen, 6525 ED Nijmegen (Netherlands); Wenderich, S.; Kruize, M. K.; Molegraaf, H. J. A.; Huijben, M.; Koster, G.; Blank, D. H. A.; Rijnders, G.; Brinkman, A.; Hilgenkamp, H. [Faculty of Science and Technology and MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands)

    2014-02-01

    We have performed high field magnetotransport measurements to investigate the interface electron gas in a high mobility SrTiO{sub 3}/SrCuO{sub 2}/LaAlO{sub 3}/SrTiO{sub 3} heterostructure. Shubnikov-de Haas oscillations reveal several 2D conduction subbands with carrier effective masses of 0.9m{sub e} and 2m{sub e}, quantum mobilities of order 2000 cm{sup 2}/V s, and band edges only a few millielectronvolts below the Fermi energy. Measurements in tilted magnetic fields confirm the 2D character of the electron gas, and show evidence of inter-subband scattering.

  11. Stochastic Quantum Gas Dynamics

    NASA Astrophysics Data System (ADS)

    Proukakis, Nick P.; Cockburn, Stuart P.

    2010-03-01

    We study the dynamics of weakly-interacting finite temperature Bose gases via the Stochastic Gross-Pitaevskii equation (SGPE). As a first step, we demonstrate [jointly with A. Negretti (Ulm, Germany) and C. Henkel (Potsdam, Germany)] that the SGPE provides a significantly better method for generating an equilibrium state than the number-conserving Bogoliubov method (except for low temperatures and small atom numbers). We then study [jointly with H. Nistazakis and D.J. Frantzeskakis (University of Athens, Greece), P.G.Kevrekidis (University of Massachusetts) and T.P. Horikis (University of Ioannina, Greece)] the dynamics of dark solitons in elongated finite temperature condensates. We demonstrate numerical shot-to-shot variations in soliton trajectories (S.P. Cockburn et al., arXiv:0909.1660.), finding individual long-lived trajectories as in experiments. In our simulations, these variations arise from fluctuations in the phase and density of the underlying medium. We provide a detailed statistical analysis, proposing regimes for the controlled experimental demonstration of this effect; we also discuss the extent to which simpler models can be used to mimic the features of ensemble-averaged stochastic trajectories.

  12. Entanglement preservation for multilevel systems under non-ideal pulse control

    E-print Network

    Z. Y. Xu; M. Feng

    2010-05-18

    We investigate how to effectively preserve the entanglement between two noninteracting multilevel oscillators coupled to a common reservoir under non-ideal pulse control. A universal characterization using fidelity is developed for the behavior of the system based on Nakajima-Zwanzig projection operator technique. Our analysis includes the validity of the approximation method and the decoherence-suppression by the non-ideal pulse control. The power of our strategy for protecting entanglement is numerically tested, showing potential applications for quantum information processing.

  13. Primitive ideals of C q [ SL(3)

    NASA Astrophysics Data System (ADS)

    Hodges, Timothy J.; Levasseur, Thierry

    1993-10-01

    The primitive ideals of the Hopf algebra C q [ SL(3)] are classified. In particular it is shown that the orbits in Prim C q [ SL(3)] under the action of the representation group H ? C *× C * are parameterized naturally by W×W, where W is the associated Weyl group. It is shown that there is a natural one-to-one correspondence between primitive ideals of C q [ SL(3)] and symplectic leaves of the associated Poisson algebraic group SL(3, C).

  14. Informationally Incomplete Quantum Tomography

    E-print Network

    Yong Siah Teo; Jaroslav Rehacek; Zdenek Hradil

    2013-11-13

    In quantum-state tomography on sources with quantum degrees of freedom of large Hilbert spaces, inference of quantum states of light for instance, a complete characterization of the quantum states for these sources is often not feasible owing to limited resources. As such, the concepts of informationally incomplete state estimation becomes important. These concepts are ideal for applications to quantum channel/process tomography, which typically requires a much larger number of measurement settings for a full characterization of a quantum channel. Some key aspects of both quantum-state and quantum-process tomography are arranged together in the form of a tutorial review article that is catered to students and researchers who are new to the field of quantum tomography, with focus on maximum-likelihood related techniques as instructive examples to illustrate these ideas.

  15. Frequency locking of single-mode 3.5-THz quantum cascade lasers using a gas cell

    E-print Network

    Ren, Y.

    We report frequency locking of two 3.5-THz third-order distributed feedback (DFB)quantum cascade lasers(QCLs) by using methanol molecular absorption lines, a proportional-integral-derivative controller, and a NbN bolometer. ...

  16. Dworkin's prudent insurance ideal: two revisions.

    PubMed

    Kurtulmus, A Faik

    2012-04-01

    This article offers two revisions to Dworkin's 'prudent insurance ideal', which aims to account for justice in the distribution of healthcare so that (a) it can deal with market failures in healthcare and (b) when applied to unjust societies it addresses health problems caused by injustice in a fair manner. PMID:22108579

  17. PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS

    E-print Network

    equality holding if dim R ? 2, but not holding in general if dim R ? 3. .... With this notation, Rees shows in [23] that vi,j is a valuation on R in the sense .... maximal ideal N that has R as a subring and b and c are elements of I such that IV =.

  18. Defining an Ideal Teacher Education Program1

    Microsoft Academic Search

    Mary M. Kennedy

    1997-01-01

    Program standards can take many different forms, as the history of the NCATE attests. One reason they take so many forms is that members of a field often disagree among themselves about what constitutes either essential minimums or ideal maximums. Because many standards are intended to guarantee minimum safeguards, they tend to focus on minimum requirements. When they aim higher,

  19. PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS

    E-print Network

    Heinzer, William

    PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS+. It is known that if I and J are projectively equivalent, then the set* * ReesI of Rees valuation rings of I is equal to the set ReesJ of Rees valuation rings of * *J and the values of I and J

  20. PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS

    E-print Network

    Heinzer, William

    PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS Catalin Ciuperca, William J. Heinzer, Louis J IN+. It is known that if I and J are projectively equivalent, then the set Rees I of Rees valuation rings of I is equal to the set Rees J of Rees valuation rings of J and the values of I and J

  1. PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS

    E-print Network

    Heinzer, William

    PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS Catalin Ciuperca, William J. Heinzer, Louis J, j # IN + . It is known that if I and J are projectively equivalent, then the set Rees I of Rees valuation rings of I is equal to the set Rees J of Rees valuation rings of J and the values of I and J

  2. The Nautilus: An Ideal Elementary School.

    ERIC Educational Resources Information Center

    Webb, Gertrude M.

    The author presents the design for an ideal elementary school that would create a climate in which children could be educated to their maximum potential. The design arises from a philosophical base that incorporates this century's research in child development and learning theory. Consideration is given to the needs of the individual at the…

  3. Ideal Spatial Adaptation by Wavelet Shrinkage

    Microsoft Academic Search

    1994-01-01

    With ideal spatial adaptation, an oracle furnishes information about how best toadapt a spatially variable estimator, whether piecewise constant, piecewise polynomial,variable knot spline, or variable bandwidth kernel, to the unknown function. Estimationwith the aid of an oracle offers dramatic advantages over traditional linear estimationby nonadaptive kernels; however, it is a priori unclear whether such performance canbe obtained by a procedure

  4. Ideal spatial adaptation by wavelet shrinkage

    Microsoft Academic Search

    DAVID L. DON; IAIN M. JOHNSTONE

    1993-01-01

    SUMMARY With ideal spatial adaptation, an oracle furnishes information about how best to adapt a spatially variable estimator, whether piecewise constant, piecewise polynomial, variable knot spline, or variable bandwidth kernel, to the unknown function. Estimation with the aid of an oracle offers dramatic advantages over traditional linear estimation by nonadapt- ive kernels; however, it is a priori unclear whether such

  5. Critical Thinking as an Educational Ideal.

    ERIC Educational Resources Information Center

    Siegel, Harvey

    Critical thinking is defined as the ability and willingness to be objective, impartial, and non-arbitrary, based on evidence. It is crucial to ethical instruction, study of theory, teaching methods, and training in skills or abilities. There are three reasons why critical thinking is an educational ideal: (1) it influences teachers to respect…

  6. Idealized Test Cases for Dynamical Core Experiments

    E-print Network

    Jablonowski, Christiane

    Idealized Test Cases for Dynamical Core Experiments Christiane Jablonowski (University of Michigan-13/2006 #12;Motivation · Test cases for 3D dynamical cores on the sphere ­ are hard to find in the literature groups ­ lack standardized & easy-to-use analysis techniques · Idea: Establish a collection of test cases

  7. Ideal” length of stay after colectomy

    Microsoft Academic Search

    David J. Schoetz; Marzina Bockler; Michael S. Rosenblatt; Shefali Malhotra; Patricia L. Roberts; John J. Murray; John A. Coller; Lawrence C. Rusin

    1997-01-01

    PURPOSE: In response to external pressure to achieve an idealized length of stay after colon resection, a study was designed to define perioperative factors that significantly impact average length of stay (ALOS). METHODS: We retrospectively reviewed the records of 226 patients undergoing open colon resection from 1988 to 1995 to determine the effects of age, type of procedure, nature of

  8. Critical Reflection as a Rationalistic Ideal

    ERIC Educational Resources Information Center

    van Woerkom, Marianne

    2010-01-01

    There is a growing interest in the concept of critical reflection in the adult learning and management literature. In this article, the author examines four different intellectual traditions that inform the use of the term "critical reflection" on the different ideals they express and the different definitions of critical reflection they use. On…

  9. Extended thermodynamics of molecular ideal gases

    Microsoft Academic Search

    G. M. Kremer

    1989-01-01

    The theory of extended thermodynamics developed by Liu and Miller (1983) and Kremer (1986) is applied to the molecular ideal gases. Consideration is given to the formulations for thermodynamic processes, the constitutive theory, the definition of equilibrium, the entropy principle, the principle of material-frame indifference, the identification of absolute temperature and transport coefficients, and the consequences of the entropy inequality.

  10. Ideal orifice pulse tube refrigerator performance

    NASA Technical Reports Server (NTRS)

    Kittel, P.

    1992-01-01

    The recent development of orifice pulse tube refrigerators has raised questions as to what limits their ultimate performance. Using an analogy to the Stirling cycle refrigerator, the efficiency (cooling power per unit input power) of an ideal orifice pulse tube refrigerator is shown to be T1/T0, the ratio of the cold temperature to the hot temperature.

  11. Ideal magnetohydrodynamic interchanges in low density plasmas

    Microsoft Academic Search

    Yi-Min Huang; Deepak Goel; A. B. Hassam

    2005-01-01

    The ideal magnetohydrodynamic equations are usually derived under the assumption VA<

  12. The Ideal Man and Woman According to University Students

    ERIC Educational Resources Information Center

    Weinstein, Lawrence; Laverghetta, Antonio V.; Peterson, Scott A.

    2009-01-01

    The present study determined if the ideal man has changed over the years and who and what the ideal woman is. We asked students at Cameron University to rate the importance of character traits that define the ideal man and woman. Subjects also provided examples of famous people exemplifying the ideal, good, average, and inferior man and woman. We…

  13. THE RATLIFFRUSH IDEALS IN A NOETHERIAN RING: A SURVEY1

    E-print Network

    Heinzer, William

    of Ratliff­Rush ideals. Much of what we discuss here is taken from the recent articles [HLS] and [HJLS]. 1. Several ways to realize Ratliff­Rush ideals. In [HLS] the behavior of the Ratliff-Rush property, there is another way to approach the associated Ratliff­Rush ideal: Theorem 2. [HLS, Fact 2.1] If I is an ideal

  14. T-splitting multiplicative sets of ideals in integral domains

    Microsoft Academic Search

    Gyu Whan Chang; Tiberiu Dumitrescu; Muhammad Zafrullah

    2005-01-01

    Let D be an integral domain. We study those multiplicative sets of ideals S of D with the property that every nonzero principal ideal dD of D can be written as dD=(AB)t with A, B ideals of D such that A contains some ideal in S and (C+B)t=D for each C?S.

  15. The ideal subject distance for passport pictures.

    PubMed

    Verhoff, Marcel A; Witzel, Carsten; Kreutz, Kerstin; Ramsthaler, Frank

    2008-07-01

    In an age of global combat against terrorism, the recognition and identification of people on document images is of increasing significance. Experiments and calculations have shown that the camera-to-subject distance - not the focal length of the lens - can have a significant effect on facial proportions. Modern passport pictures should be able to function as a reference image for automatic and manual picture comparisons. This requires a defined subject distance. It is completely unclear which subject distance, in the taking of passport photographs, is ideal for the recognition of the actual person. We show here that the camera-to-subject distance that is perceived as ideal is dependent on the face being photographed, even if the distance of 2m was most frequently preferred. So far the problem of the ideal camera-to-subject distance for faces has only been approached through technical calculations. We have, for the first time, answered this question experimentally with a double-blind experiment. Even if there is apparently no ideal camera-to-subject distance valid for every face, 2m can be proposed as ideal for the taking of passport pictures. The first step would actually be the determination of a camera-to-subject distance for the taking of passport pictures within the standards. From an anthropological point of view it would be interesting to find out which facial features allow the preference of a shorter camera-to-subject distance and which allow the preference of a longer camera-to-subject distance. PMID:18450396

  16. Conformations of silicon-containing rings. 5. Conformational properties of 1-methyl-1-silacyclohexane: gas electron diffraction, low-temperature NMR, and quantum chemical calculations.

    PubMed

    Arnason, Ingvar; Kvaran, Agust; Jonsdottir, Sigridur; Gudnason, Palmar I; Oberhammer, Heinz

    2002-05-31

    The molecular structure of 1-methyl-1-silacyclohexane 3 has been determined by gas electron diffraction (GED). The conformational preference of the methyl group was studied experimentally in the gas phase (GED) and in solution (low-temperature (13)C NMR) and by quantum chemical calculations (HF, MP2, and B3LYP with 6-31G basis sets and mPW1PW91/6-311G(2df,p)). Both experimental methods result in a preference of the equatorial position of the methyl group, 68(7)% in the gas phase at 298 K and 74(1)% in solution at 110 K. The calculations predict 68-73% equatorial conformer at room temperature. From coalescence temperatures, Gibbs free energies of activation for ring inversion DeltaG++ (eq --> ax) = 5.81(18) and DeltaG++ (ax --> eq) = 5.56(18) kcal mol(-1) were derived. The calculated values for DeltaG++ (eq --> ax) are 5.92 (B3LYP) and 5.84 kcal mol(-1) (mPW1PW91). PMID:12027699

  17. New insights into the ideal adsorbed solution theory.

    PubMed

    Furmaniak, Sylwester; Koter, Stanis?aw; Terzyk, Artur P; Gauden, Piotr A; Kowalczyk, Piotr; Rychlicki, Gerhard

    2015-03-21

    The GCMC technique is used for simulation of adsorption of CO2-CH4, CO2-N2 and CH4-N2 mixtures (at 298 K) on six porous carbon models. Next we formulate a new condition of the IAS concept application, showing that our simulated data obey this condition. Calculated deviations between IAS predictions and simulation results increase with the rise in pressure as in the real experiment. For the weakly adsorbed mixture component the deviation from IAS predictions is higher, especially when its content in the gas mixture is low, and this is in agreement with the experimental data. Calculated activity coefficients have similar plots to deviations between IAS and simulations, moreover obtained from simulated data activity coefficients are similar qualitatively as well as quantitatively to experimental data. Since the physical interpretation of activity coefficients is completely lacking we show for the first time that they can be described by the formulas derived from the expression for G(ex) for the ternary mixture. Finally we also for the first time show the linear relationship between the chemical potentials of nonideal and ideal solutions and the reduced temperature of interacting mixture components, and it is proved that the deviation from ideality is larger if adsorption occurs in a more microporous system. PMID:25689966

  18. Int-soft (generalized) bi-ideals of semigroups.

    PubMed

    Jun, Young Bae; Song, Seok-Zun

    2015-01-01

    The notions of int-soft semigroups and int-soft left (resp., right) ideals in semigroups are studied in the paper by Song et al. (2014). In this paper, further properties and characterizations of int-soft left (right) ideals are studied, and the notion of int-soft (generalized) bi-ideals is introduced. Relations between int-soft generalized bi-ideals and int-soft semigroups are discussed, and characterizations of (int-soft) generalized bi-ideals and int-soft bi-ideals are considered. Given a soft set (?;S) over U, int-soft (generalized) bi-ideals generated by (?;S) are established. PMID:25710051

  19. Subcycle engineering of laser filamentation in gas by harmonic seeding

    E-print Network

    Béjot, P; Billard, F; Doussot, J; Hertz, E; Lavorel, B; Faucher, O

    2014-01-01

    Manipulating at will the propagation dynamics of high power laser pulses is a long-standing dream whose accomplishment would lead to the control of a plethora of fascinating physical phenomena emerging from laser-matter interaction. The present work represents a significant step towards such an ideal control by manipulating the nonlinear optical properties of the gas medium at the quantum level. This is accomplished by engineering the intense laser pulse experiencing filamentation at the subcycle level with a relatively weak (about 1%) third-harmonic radiation. The control results from quantum interferences between a single and a two-color (mixing the fundamental frequency with its 3rd harmonic) ionization channel. This mechanism, which depends on the relative phase between the two electric fields, is responsible for wide refractive index modifications in relation with significant enhancement or suppression of the ionization rate. As a first application, we demonstrate the production and control of an axially...

  20. Thermodynamics of the ideal overlap quarks on the lattice

    SciTech Connect

    Banerjee, Debasish; Gavai, R. V.; Sharma, Sayantan [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

    2008-07-01

    The thermodynamics of massless ideal gas of overlap quarks has been investigated both analytically and numerically for both zero and nonzero baryon chemical potential. Any {mu}{sup 2} divergence is shown analytically to be absent for a class of actions with nonzero chemical potential. All such actions are shown to violate chiral invariance. While the parameter M can be shown to be irrelevant in the continuum limit, as expected, it is shown numerically that the continuum limit can be reached with relatively coarser lattices for 1.5{<=}M{<=}1.6. Numerical limitations of the existing method of introduction of chemical potential are demonstrated. Finally we also show that the energy density for the massive overlap fermions has the correct continuum limit.

  1. Searching Out the Ideal: Awareness of Ideal Body Standards Predicts Lower Global Self-esteem in Women

    Microsoft Academic Search

    Emily Balcetis; Shana Cole; Marie B. Chelberg; Mark Alicke

    2012-01-01

    Does awareness of female body ideals affect women's global self-esteem? We measured awareness of ideal standards for beauty via two approaches. As one approach, participants (55 undergraduate women) self-reported their general propensity to be aware of society's thin ideal standard. As a second approach, we measured visual attention orienting to ideal standards; we covertly measured participants' eye movements to peers'

  2. Gröbner Bases of Ideals Defined by Functionals with an Application to Ideals of Projective Points

    Microsoft Academic Search

    Maria Grazia Marinari; H. Michael Möller; Teo Mora

    1993-01-01

    In this paper we study 0-dimensional polynomial ideals defined by a dual basis, i.e. as the set of polynomials which are in the kernel of a set of linear morhpisms from the polynomial ring to the base field. For such ideals, we give polynomial complexity algorithms to compute a Gršbner basis, generalizing the Buchberger-Mšller algorithm for computing a basis of

  3. Light absorption during alkali atom-noble gas atom interactions at thermal energies: A quantum dynamics treatment

    Microsoft Academic Search

    Alexander B. Pacheco; Andrés Reyes; David A. Micha

    2006-01-01

    The absorption of light during atomic collisions is treated by coupling electronic excitations, treated quantum mechanically, to the motion of the nuclei described within a short de Broglie wavelength approximation, using a density matrix approach. The time-dependent electric dipole of the system provides the intensity of light absorption in a treatment valid for transient phenomena, and the Fourier transform of

  4. Non-ideal solution thermodynamics of cytoplasm.

    PubMed

    Ross-Rodriguez, Lisa U; Elliott, Janet A W; McGann, Locksley E

    2012-10-01

    Quantitative description of the non-ideal solution thermodynamics of the cytoplasm of a living mammalian cell is critically necessary in mathematical modeling of cryobiology and desiccation and other fields where the passive osmotic response of a cell plays a role. In the solution thermodynamics osmotic virial equation, the quadratic correction to the linear ideal, dilute solution theory is described by the second osmotic virial coefficient. Herein we report, for the first time, intracellular solution second osmotic virial coefficients for four cell types [TF-1 hematopoietic stem cells, human umbilical vein endothelial cells (HUVEC), porcine hepatocytes, and porcine chondrocytes] and further report second osmotic virial coefficients indistinguishable from zero (for the concentration range studied) for human hepatocytes and mouse oocytes. PMID:23840923

  5. Logic of infinite quantum systems

    NASA Astrophysics Data System (ADS)

    Mundici, Daniele

    1993-10-01

    Limits of sequences of finite-dimensional (AF) C *-algebras, such as the CAR algebra for the ideal Fermi gas, are a standard mathematical tool to describe quantum statistical systems arising as thermodynamic limits of finite spin systems. Only in the infinite-volume limit one can, for instance, describe phase transitions as singularities in the thermodynamic potentials, and handle the proliferation of physically inequivalent Hilbert space representations of a system with infinitely many degrees of freedom. As is well known, commutative AF C *-algebras correspond to countable Boolean algebras, i.e., algebras of propositions in the classical two-valued calculus. We investigate the noncommutative logic properties of general AF C *-algebras, and their corresponding systems. We stress the interplay between Gödel incompleteness and quotient structures in the light of the “nature does not have ideals” program, stating that there are no quotient structures in physics. We interpret AF C *-algebras as algebras of the infinite-valued calculus of Lukasiewicz, i.e., algebras of propositions in Ulam's “ twenty questions” game with lies.

  6. Multiplicity scaling in ideal and viscous hydrodynamics

    Microsoft Academic Search

    Song Huichao; Ulrich Heinz

    2008-01-01

    Using numerical results from ideal and viscous relativistic hydrodynamic simulations with three different equations of state, for Au+Au and Cu+Cu collisions at different centralities and initial energy densities, we explore the dependence of the eccentricity-scaled elliptic flow, v\\/, and the produced entropy fraction, S\\/S, on the final charged hadron multiplicity density dN{sub ch}\\/dy per unit transverse overlap area S,(1\\/S)dN{sub ch}\\/dy.

  7. Multiplicity scaling in ideal and viscous hydrodynamics

    Microsoft Academic Search

    Huichao Song; Ulrich W. Heinz

    2008-01-01

    Using numerical results from ideal and viscous relativistic hydrodynamic simulations with three different equations of state, for Au+Au and Cu+Cu collisions at different centralities and initial energy densities, we explore the dependence of the eccentricity-scaled elliptic flow, v2\\/?, and the produced entropy fraction, DeltaS\\/S0, on the final charged hadron multiplicity density dNch\\/dy per unit transverse overlap area S,(1\\/S)dNch\\/dy. The viscous

  8. Extended thermodynamics of molecular ideal gases

    NASA Astrophysics Data System (ADS)

    Kremer, G. M.

    1989-02-01

    The theory of extended thermodynamics developed by Liu and Miller (1983) and Kremer (1986) is applied to the molecular ideal gases. Consideration is given to the formulations for thermodynamic processes, the constitutive theory, the definition of equilibrium, the entropy principle, the principle of material-frame indifference, the identification of absolute temperature and transport coefficients, and the consequences of the entropy inequality. The relationships between this extended theory and both conventional thermodynamics and the kinetic theory of molecular gases are explored.

  9. Linear ideal MHD stability calculations for ITER

    SciTech Connect

    Hogan, J.T.

    1988-01-01

    A survey of MHD stability limits has been made to address issues arising from the MHD--poloidal field design task of the US ITER project. This is a summary report on the results obtained to date. The study evaluates the dependence of ballooning, Mercier and low-n ideal linear MHD stability on key system parameters to estimate overall MHD constraints for ITER. 17 refs., 27 figs.

  10. Stability of idealized condensed phase detonations

    Microsoft Academic Search

    Mark Short; Iana I. Anguelova; Tariq D. Aslam; John B. Bdzil; Andrew K. Henrick; Gary J. Sharpe

    The linear and nonlinear stability of Chapman-Jouguet (CJ) and overdriven detonations of Zeldovich-von Neumann-Doring (ZND) type are examined in the context of the idealized condensed phase (liquid or solid) detonation model. This model includes a two-component mixture (fuel and product), with a one-step irre- versible reaction possessing a rate that is pressure-sensitive (p n ) and has a variable reaction

  11. Principles for designing ideal protein structures

    PubMed Central

    Koga, Nobuyasu; Tatsumi-Koga, Rie; Liu, Gaohua; Xiao, Rong; Acton, Thomas B.; Montelione, Gaetano T.; Baker, David

    2013-01-01

    Unlike random heteropolymers, natural proteins fold into unique ordered structures. Understanding how these are encoded in amino-acid sequences is complicated by energetically unfavourable non-ideal features—for example kinked ?-helices, bulged ?-strands, strained loops and buried polar groups—that arise in proteins from evolutionary selection for biological function or from neutral drift. Here we describe an approach to designing ideal protein structures stabilized by completely consistent local and non-local interactions. The approach is based on a set of rules relating secondary structure patterns to protein tertiary motifs, which make possible the design of funnel-shaped protein folding energy landscapes leading into the target folded state. Guided by these rules, we designed sequences predicted to fold into ideal protein structures consisting of ?-helices, ?-strands and minimal loops. Designs for five different topologies were found to be monomeric and very stable and to adopt structures in solution nearly identical to the computational models. These results illuminate how the folding funnels of natural proteins arise and provide the foundation for engineering a new generation of functional proteins free from natural evolution. PMID:23135467

  12. Ramsey interferometry with a two-level generalized Tonks-Girardeau gas

    SciTech Connect

    Mousavi, S. V.; Campo, A. del; Lizuain, I.; Muga, J. G. [Departamento de Quimica-Fisica, Universidad del Pais Vasco, Apartado 644, 48080 Bilbao (Spain) and Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran (Iran, Islamic Republic of); Departamento de Quimica-Fisica, Universidad del Pais Vasco, Apartado 644, 48080 Bilbao (Spain)

    2007-09-15

    We propose a solvable generalization of the Tonks-Girardeau model that describes a coherent one-dimensional (1D) gas of cold two-level bosons which interact with two external fields in a Ramsey interferometer. They also interact among themselves by idealized, infinitely strong contact potentials, with interchange of momentum and internal state. We study the corresponding Ramsey fringes and the quantum projection noise which, essentially unaffected by the interactions, remains that for ideal bosons. The dual system of this gas, an ideal gas of two-level fermions coupled by the interaction with the separated fields, produces the same fringes and noise fluctuations. The cases of time-separated and spatially separated fields are studied. For spatially separated fields the fringes may be broadened slightly by increasing the number of particles, but only for large particle numbers far from present experiments with Tonks-Girardeau gases. The uncertainty in the determination of the atomic transition frequency diminishes, essentially with the inverse root of the particle number. The difficulties to implement the model experimentally and possible shortcomings of strongly interacting 1D gases for frequency standards and atomic clocks are discussed.

  13. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Remote laser detection of natural gas leakages from pipelines

    NASA Astrophysics Data System (ADS)

    Petukhov, V. O.; Gorobets, V. A.; Andreev, Yu M.; Lanskii, G. V.

    2010-02-01

    A differential absorption lidar based on a tunable TEA CO2 laser emitting at 42 lines of the 'hot' 0111 — 1110 band in the range from 10.9 to 11.4 ?m is developed for detecting natural gas leakages from oil pipelines by measuring the ethane content in the atmosphere. The ethane detection sensitivity is 0.9 ppm km. The presence of methane does not distort the measurement results. The developed lidar can detect the natural gas leakage from kilometre heights at the flying velocities up to 200 km h-1 and a probe pulse repetition rate of 5 Hz.

  14. Ideal Fluids, the Quark Gluon Plasma, and Hadronic Gases

    NASA Astrophysics Data System (ADS)

    Demir, Nasser

    2015-01-01

    A detailed comparison between two methods to calculate the shear viscosity coefficient of a hot hadronic gas is presented. We choose two systems in this comparison which are massless particles with current algebra cross section and a mixture comprised of pions with rho resonances. The two methods involved are the Green-Kubo method, applied using the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) model to simulate the hadronic medium, and the Chapman-Enskog method. In addition, the effect of the resonance lifetime on the shear viscosity coefficient is investigated.

  15. Trapped quantum light

    NASA Astrophysics Data System (ADS)

    Brune, M.; Raimond, J. M.

    2015-04-01

    Matter-field interaction finds its simplest implementation in Cavity Quantum Electrodynamics (CQED). A single two-level atom is coupled to a few photons stored in a single mode of a high-quality resonator. In the strong-coupling regime, the coherent atom-field interaction overwhelms dissipative processes. This situation illustrates the basic quantum postulates. It is also ideal for the exploration of the quantum-classical boundary and for the realization of quantum information protocols. We briefly describe the general frame of CQED. We illustrate its fundamental interest by discussing two recent experiments, performed with circular Rydberg atoms and superconducting millimeter-wave cavities.

  16. Ultra-shallow quantum dots in an undoped GaAs/AlGaAs two-dimensional electron gas

    SciTech Connect

    Mak, W. Y.; Sfigakis, F.; Beere, H. E.; Farrer, I.; Griffiths, J. P.; Jones, G. A. C.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom)] [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Das Gupta, K. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom) [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Klochan, O.; Hamilton, A. R. [School of Physics, University of New South Wales, Sydney (Australia)] [School of Physics, University of New South Wales, Sydney (Australia)

    2013-03-11

    We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy. Due to the absence of dopants, an improvement of more than one order of magnitude in mobility (at 2 Multiplication-Sign 10{sup 11} cm{sup -2}) with respect to doped heterostructures with similar depths is observed. These undoped wafers can easily be gated with surface metallic gates patterned by e-beam lithography, as demonstrated here from single-level transport through a quantum dot showing large charging energies (up to 1.75 meV) and excited state energies (up to 0.5 meV).

  17. Trace-Gas Detection in Ambient Air with a Thermoelectrically Cooled, Pulsed Quantum-Cascade Distributed Feedback Laser

    Microsoft Academic Search

    Anatoliy A. Kosterev; Frank K. Tittel; Claire Gmachl; Federico Capasso; Deborah L. Sivco; James N. Baillargeon; Albert L. Hutchinson; Alfred Y. Cho

    2000-01-01

    A pulsed quantum-cascade distributed feedback laser operating at near room temperature was used for sensitive high-resolution IR absorption spectroscopy of ambient air at a wavelength of 8 m. Near-transform-limited laser pulses were obtained owing to short ( 5-ns) current pulse excitation and optimized electrical coupling. Fast and slow computer-controlled frequency scanning techniques were implemented and characterized. Fast computer-controlled laser wavelength

  18. Applications of quantum cascade lasers for sensitive trace gas measurements of CO, CH 4 , N 2 O and HCHO

    Microsoft Academic Search

    C. L. Schiller; H. Bozem; C. Gurk; U. Parchatka; R. Königstedt; G. W. Harris; J. Lelieveld; H. Fischer

    2008-01-01

    We describe here a sensitive quantum cascade laser absorption spectrometer (QCLAS) employed for aircraft based measurements\\u000a during the GABRIEL 2005 and HOOVER 2006 and 2007 campaigns. This 3-channel instrument measures CO, HCHO, CH4 and N2O using a 64-m path double corner cube White cell. Performance of the instrument was examined for the four species and precisions\\u000a for CO, N2O and

  19. arXiv:cond-mat/9807406v130Jul1998 Exploring a quantum degenerate gas of fermionic atoms

    E-print Network

    Jin, Deborah

    phenomena in the behavior of an ultra- cold, trapped gas of fermionic atoms. We find that quan- tum must be p-wave since Fermi-Dirac (FD) statistics prohibits s-wave collisions between identical particles. However, the p-wave colli- sion cross-section is suppressed at low temperature due

  20. Population transfer and rapid passage effects in a low pressure gas using a continuous wave quantum cascade laser.

    PubMed

    McCormack, E A; Lowth, H S; Bell, M T; Weidmann, D; Ritchie, G A D

    2012-07-21

    A continuous wave quantum cascade laser (cw-QCL) operating at 10 ?m has been used to record absorption spectra of low pressure samples of OCS in an astigmatic Herriott cell. As a result of the frequency chirp of the laser, the spectra show clearly the effects of rapid passage on the absorption line shape. At the low chirp rates that can be obtained with the cw-QCL, population transfer between rovibrational quantum states is predicted to be much more efficient than in typical pulsed QCL experiments. This optical pumping is investigated by solving the Maxwell Bloch equations to simulate the propagation of the laser radiation through an inhomogeneously broadened two-level system. The calculated absorption profiles show good quantitative agreement with those measured experimentally over a range of chirp rates and optical thicknesses. It is predicted that at a low chirp rate of 0.13 MHz ns(-1), the population transfer between rovibrational quantum states is 12%, considerably more than that obtained at the higher chirp rates utilised in pulsed QCL experiments. PMID:22830701

  1. QUANTUM CRYPTOGRAPHY QUANTUM COMPUTING

    E-print Network

    Bachoc, Christine

    QUANTUM CRYPTOGRAPHY QUANTUM COMPUTING 1. Quantum cryptography : from basic principles to practical realizations. 2. Quantum computing : a conceptual revolution hard to materialize Philippe Grangier, Institut d useful for quantum cryptography QUBITS | 0 | 1 cos() | 0 + sin() | 1 #12;QUANTUM COMPUTING

  2. The equations of the ideal latches

    E-print Network

    Serban E. Vlad

    2004-11-08

    The latches are simple circuits with feedback from the digital electrical engineering. We have included in our work the C element of Muller, the RS latch, the clocked RS latch, the D latch and also circuits containing two interconnected latches: the edge triggered RS flip-flop, the D flip-flop, the JK flip-flop, the T flip-flop. The purpose of this study is to model with equations the previous circuits, considered to be ideal, i.e. non-inertial. The technique of analysis is the pseudoboolean differential calculus.

  3. "The Scientific Method" as Myth and Ideal

    NASA Astrophysics Data System (ADS)

    Woodcock, Brian A.

    2014-10-01

    "The Scientific Method" as it has been portrayed in popular and introductory contexts has been declared a myth. The variation that one finds in introductory presentations of "The Scientific Method" is explained by the fact that there is no canonical account among historians and philosophers of science. What, in particular, is wrong with "The Scientific Method"? This essay provides a fairly comprehensive survey of shortcomings of "The Scientific Method". Included are corrections to several misconceptions that often accompany such presentations. Rather than treating "The Scientific Method" as a useful approximation or an ideal, the myth should be discarded. Lessons can be learned for introductory pedagogical contexts from considering the shortcomings of the myth.

  4. Cylindrical ideal magnetohydrodynamic equilibria with incompressible flows

    SciTech Connect

    Throumoulopoulos, G.N. [Section of Theoretical Physics, Department of Physics, University of Ioannina, GR 451 10 Ioannina (Greece)] [Section of Theoretical Physics, Department of Physics, University of Ioannina, GR 451 10 Ioannina (Greece); Tasso, H. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)] [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

    1997-05-01

    It is proved that (a) the solutions of the ideal magnetohydrodynamic equation, which describes the equilibrium states of a cylindrical plasma with purely poloidal flow and arbitrary cross-sectional shape [G. N. Throumoulopoulos and G. Pantis, Plasma Phys. Controlled Fusion {bold 38}, 1817 (1996)], are also valid for incompressible equilibrium flows with the axial velocity component being a free surface quantity and that (b) for the case of isothermal incompressible equilibria the magnetic surfaces necessarily have a circular cross-section. {copyright} {ital 1997 American Institute of Physics.}

  5. Idealized simulations of aerosol influences on tornadogenesis

    NASA Astrophysics Data System (ADS)

    Lerach, David G.; Gaudet, Brian J.; Cotton, William R.

    2008-12-01

    Numerical simulations of an idealized supercell thunderstorm were performed to assess effects of increased aerosol concentrations acting as cloud condensation nuclei (CCN) and giant CCN (GCCN) on tornadogenesis. Initial background profiles of CCN and GCCN concentrations were set to represent ``clean'' continental and aerosol-polluted environments, respectively. With a reduction in warm- and cold-rain processes, the polluted environment produced a longer-lived supercell with a well-defined rear flank downdraft (RFD) and relatively weak forward flank downdraft (FFD) that produced weak evaporative cooling, a weak cold pool, and an EF-1 tornado. The clean environment produced no tornado and was less favorable for tornadogenesis.

  6. Ideal pre-conceptual design development

    SciTech Connect

    Gentzlinger, R.; Mendelsohn, S.; Abel, B. [Grumman Corp., Princeton, NJ (United States)] [and others

    1993-12-31

    A preconceptual design has been produced for a plasma device to further divertor concepts and validate technology in support of the International Thermonuclear Experimental Reactor program. The ITER Diverter Experiment and Laboratory (IDEAL) design effort is to develop a reliable, maintainable and robust facility for steady-state divertor simulation experiments. The configuration includes a 30 meter vacuum vessel, enclosed within a set of 30 high field superconducting solenoid modules, a resistive quadrupole coil set, a radio-frequency heating system and a complement of diagnostics. It is planned to utilize existing facilities, and off-the-shelf hardware, wherever possible to maximize technological return on investment.

  7. Momentum spectra, anisotropic flow, and ideal fluids

    E-print Network

    N. Borghini; J. -Y. Ollitrault

    2006-07-28

    If the matter produced in ultrarelativistic heavy-ion collisions reaches thermal equilibrium, its subsequent evolution follows the laws of ideal fluid dynamics. We show that general predictions can be made on this basis alone, irrespective of the details of the hydrodynamical model. We derive several scaling rules for momentum spectra and anisotropic flow (in particular the elliptic flow, v2, and the hexadecupole flow, v4) of identified particles. Comparison with existing data is briefly discussed, and qualitative predictions are made for LHC.

  8. Hamiltonian description of the ideal fluid

    SciTech Connect

    Morrison, P.J.

    1994-01-01

    Fluid mechanics is examined from a Hamiltonian perspective. The Hamiltonian point of view provides a unifying framework; by understanding the Hamiltonian perspective, one knows in advance (within bounds) what answers to expect and what kinds of procedures can be performed. The material is organized into five lectures, on the following topics: rudiments of few-degree-of-freedom Hamiltonian systems illustrated by passive advection in two-dimensional fluids; functional differentiation, two action principles of mechanics, and the action principle and canonical Hamiltonian description of the ideal fluid; noncanonical Hamiltonian dynamics with examples; tutorial on Lie groups and algebras, reduction-realization, and Clebsch variables; and stability and Hamiltonian systems.

  9. The equations of the ideal latches

    E-print Network

    Serban E. Vlad

    2008-04-05

    The latches are simple circuits with feedback from the digital electrical engineering. We have included in our work the C element of Muller, the RS latch, the clocked RS latch, the D latch and also circuits containing two interconnected latches: the edge triggered RS flip-flop, the D flip-flop, the JK flip-flop, the T flip-flop. The purpose of this study is to model with equations the previous circuits, considered to be ideal, i.e. non-inertial. The technique of analysis is the pseudoboolean differential calculus.

  10. Das ideale Quantenlabor: Bose-Einstein-Kondensation

    NASA Astrophysics Data System (ADS)

    Sengstock, Klaus; Bongs, Kai; Reichel, Jakob

    2003-07-01

    Bose-Einstein-Kondensate (BEC) sind extrem kalte Gase aus bosonischen Atomen, die sich alle im energetischen Grundzustand versammeln. Ein BEC ist ein perfektes Quantenlabor. Es bietet eine makroskopische Materiewelle aus vielen Tausend Teilchen an, die dem Experiment offen zugänglich ist. Das unterscheidet es von anderen makroskopischen Quantenzuständen wie der Suprafluidität oder der Supraleitung, denn diese verbergen sich in Flüssigkeiten oder Festkörpern. Das BEC ist also ein ideales Modellsystem, um diese und andere Phänomene der Quantenmechanik zu studieren. Neue Perspektiven eröffnet die schnelle Erzeugung und leichte Manipulation eines Kondensats auf einem Mikrochip. Dazu gehören auch vielfältige Anwendungen bis hin zum Quantencomputer.

  11. Broken symmetry in ideal magnetohydrodynamic turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1993-01-01

    A numerical study of the long-time evolution of a number of cases of inviscid, isotropic, incompressible, three-dimensional fluid, and magneto-fluid turbulence has been completed. The results confirm that ideal magnetohydrodynamic turbulence is non-ergodic if there is no external magnetic field present. This is due essentially to a canonical symmetry being broken in an arbitrary dynamical representation. The broken symmetry manifests itself as a coherent structure, i.e., a non-zero time-averaged part of the turbulent magnetic field. The coherent structure is observed, in one case, to contain about eighteen percent of the total energy.

  12. Poset resolutions and lattice-linear monomial ideals

    Microsoft Academic Search

    Timothy B. P. Clark

    2010-01-01

    We introduce the class of lattice-linear monomial ideals and use the lcm-lattice to give an explicit construction for their minimal free resolution. The class of lattice-linear ideals includes (among others) the class of monomial ideals with a linear free resolution and the class of Scarf monomial ideals. Our main tool is a new construction by Tchernev that produces from a

  13. Real-Time Trace Gas Sensing of Fluorocarbons using a Swept-wavelength External Cavity Quantum Cascade Laser

    SciTech Connect

    Phillips, Mark C.; Taubman, Matthew S.; Bernacki, Bruce E.; Cannon, Bret D.; Stahl, Robert D.; Schiffern, John T.; Myers, Tanya L.

    2014-05-04

    We present results demonstrating real-time sensing of four different fluorocarbons at low-ppb concentrations using an external cavity quantum cascade laser (ECQCL) operating in a swept-wavelength configuration. The ECQCL was repeatedly swept over its full tuning range at a 20 Hz rate with a scan rate of 3535 cm-1/s, and a detailed characterization of the ECQCL scan stability and repeatability is presented. The sensor was deployed on a mobile automotive platform to provide spatially resolved detection of fluorocarbons in outdoor experiments. Noise-equivalent detection limits of 800-1000 parts-per-trillion (ppt) are demonstrated for 1 s integration times.

  14. The Ideal Structure of Cuntz-Krieger Algebras

    Microsoft Academic Search

    Astrid An Huef; Iain Raeburn

    1996-01-01

    We construct a universal Cuntz-Krieger algebra AO A , which isisomorphic to the usual Cuntz-Krieger algebra O A when A satises thecondition (I) of Cuntz and Krieger. Cuntz's classication of ideals inO A when A satises condition (II) extends to a classication of thegauge invariant ideals in AO A . We use this to describe the topologyon the primitive ideal

  15. Psychological Bulletin The Predictive Validity of Ideal Partner Preferences: A

    E-print Network

    Reber, Paul J.

    Psychological Bulletin The Predictive Validity of Ideal Partner Preferences: A Review and Meta. (2013, April 15). The Predictive Validity of Ideal Partner Preferences: A Review and Meta-Analysis. Psychological Bulletin. Advance online publication. doi: 10.1037/a0032432 #12;The Predictive Validity of Ideal

  16. Black and White Adolescent Females Perceptions of Ideal Body Size.

    ERIC Educational Resources Information Center

    Parnell, Kathy; And Others

    1996-01-01

    White and black adolescent females (n=344) participated in a survey of ideal body size beliefs using a questionnaire and 9 female and male body size drawings. Black females preferred a significantly heavier ideal female body size than whites and perceived that their parents and friends would select as ideal a significantly heavier female body size…

  17. Promoting Spiritual Ideals through Design Thinking in Public Schools

    ERIC Educational Resources Information Center

    Tan, Charlene; Wong, Yew-Leong

    2012-01-01

    Against a backdrop of the debates on religious education in public or state schools, we argue for the introduction of "spiritual ideals" into the public school curriculum. We distinguish our notion of spiritual ideals from "religious ideals" as conceptualised by De Ruyter and Merry. While we agree with De Ruyter and Merry that ideas drawn from…

  18. The Calculation of Radical Ideals in Positive Characteristic Gregor Kemper

    E-print Network

    Kemper, Gregor

    The Calculation of Radical Ideals in Positive Characteristic Gregor Kemper IWR, Universit 13, 2002 Abstract We propose an algorithm for computing the radical of a polynomial ideal in positive of the radical I of a given ideal I K[x1, . . . , xn] in a polynomial ring is one of the basic tasks

  19. Ideal transformers in the synthesis of analog computer circuits

    Microsoft Academic Search

    R. H. MacNeal; G. D. McCann

    1955-01-01

    The need for ideal transformers in the solution of network synthesis problems, especially in multi-terminal problems, has long been recognized. Nevertheless, there has been a general feeling that solutions to synthesis problems containing ideal transformers are of little more than academic interest because of the impracticability of constructing transformers good enough to be called ideal. Whenever possible, inductances in the

  20. Nonlinear stability of ideal fluid equilibria

    SciTech Connect

    Holm, D.D.

    1988-01-01

    The Lyapunov method for establishing stability is related to well- known energy principles for nondissipative dynamical systems. A development of the Lyapunov method for Hamiltonian systems due to Arnold establishes sufficient conditions for Lyapunov stability by using the energy plus other conserved quantities, together with second variations and convexity estimates. When treating the stability of ideal fluid dynamics within the Hamiltonian framework, a useful class of these conserved quantities consists of the Casimir functionals, which Poisson-commute with all functionals of the dynamical fluid variables. Such conserved quantities, when added to the energy, help to provide convexity estimates that bound the growth of perturbations. These convexity estimates, in turn, provide norms necessary for establishing Lyapunov stability under the nonlinear evolution. In contrast, the commonly used second variation or spectral stability arguments only prove linearized stability. As ideal fluid examples, in these lectures we discuss planar barotropic compressible fluid dynamics, the three-dimensional hydrostatic Boussinesq model, and a new set of shallow water equations with nonlinear dispersion due to Basdenkov, Morosov, and Pogutse(1985). Remarkably, all three of these samples have the same Hamiltonian structure and, thus, possess the same Casimir functionals upon which their stability analyses are based. We also treat stability of modified quasigeostrophic flow, a problem whose Hamiltonian structure and Casimirs closely resemble Arnold's original example. Finally, we discuss some aspects of conditional stability and the applicability of Arnold's development of the Lyapunov technique. 100 refs.

  1. Optimal Forager against Ideal Free Distributed Prey.

    PubMed

    Garay, József; Cressman, Ross; Xu, Fei; Varga, Zoltan; Cabello, Tomás

    2015-07-01

    The introduced dispersal-foraging game is a combination of prey habitat selection between two patch types and optimal-foraging approaches. Prey's patch preference and forager behavior determine the prey's survival rate. The forager's energy gain depends on local prey density in both types of exhaustible patches and on leaving time. We introduce two game-solution concepts. The static solution combines the ideal free distribution of the prey with optimal-foraging theory. The dynamical solution is given by a game dynamics describing the behavioral changes of prey and forager. We show (1) that each stable equilibrium dynamical solution is always a static solution, but not conversely; (2) that at an equilibrium dynamical solution, the forager can stabilize prey mixed patch use strategy in cases where ideal free distribution theory predicts that prey will use only one patch type; and (3) that when the equilibrium dynamical solution is unstable at fixed prey density, stable behavior cycles occur where neither forager nor prey keep a fixed behavior. PMID:26098343

  2. Ideal teleradiology configuration from a physician's perspective

    NASA Astrophysics Data System (ADS)

    Leckie, Robert G.; de Treville, Robert E.; Lyche, David K.; Norton, Gary S.; Goeringer, Fred; Willis, Charles E.; Cawthon, Michael A.; Smith, Donald V.; Hansen, Mark

    1993-09-01

    Teleradiology systems are being developed and implemented around the world. The ultimate success of these systems depends on the acceptance by the end users -- the physicians. From a physician's perspective, several major areas need to be addressed in the ideal situation. The areas include (1) image quality and ease of manipulation of images on a workstation; (2) expert interpretation by a specialist or sub-specialist; (3) good communication between the radiologist, radiology technologist, primary care physician, and the patient; (4) accessibility to images; (5) system reliability; (6) costs and assistance in balancing workloads; and (7) education and research. The Medical Diagnostic Imaging Support (MDIS) System is a large tri-service project to install picture archive and communication systems (PACS) and teleradiology at military medical treatment facilities across the United States and abroad. The first sites primarily involved with teleradiology will be installed in the summer of 1993. Ways in which the MDIS teleradiology system address the physicians' ideal configuration as well as possible future improvements are discussed.

  3. Global invariants in ideal magnetohydrodynamic turbulence

    SciTech Connect

    Shebalin, John V. [Astromaterials Research Office, NASA Johnson Space Center, Houston, Texas 77058-3696 (United States)] [Astromaterials Research Office, NASA Johnson Space Center, Houston, Texas 77058-3696 (United States)

    2013-10-15

    Magnetohydrodynamic (MHD) turbulence is an important though incompletely understood factor affecting the dynamics of many astrophysical, geophysical, and technological plasmas. As an approximation, viscosity and resistivity may be ignored, and ideal MHD turbulence may be investigated by statistical methods. Incompressibility is also assumed and finite Fourier series are used to represent the turbulent velocity and magnetic field. The resulting model dynamical system consists of a set of independent Fourier coefficients that form a canonical ensemble described by a Gaussian probability density function (PDF). This PDF is similar in form to that of Boltzmann, except that its argument may contain not just the energy multiplied by an inverse temperature, but also two other invariant integrals, the cross helicity and magnetic helicity, each multiplied by its own inverse temperature. However, the cross and magnetic helicities, as usually defined, are not invariant in the presence of overall rotation or a mean magnetic field, respectively. Although the generalized form of the magnetic helicity is known, a generalized cross helicity may also be found, by adding terms that are linear in the mean magnetic field and angular rotation vectors, respectively. These general forms are invariant even in the presence of overall rotation and a mean magnetic field. We derive these general forms, explore their properties, examine how they extend the statistical theory of ideal MHD turbulence, and discuss how our results may be affected by dissipation and forcing.

  4. From the ideal market to the ideal clinic: constructing a normative standard of fairness for human subjects research.

    PubMed

    Phillips, Trisha

    2011-02-01

    Preventing exploitation in human subjects research requires a benchmark of fairness against which to judge the distribution of the benefits and burdens of a trial. This paper proposes the ideal market and its fair market price as a criterion of fairness. The ideal market approach is not new to discussions about exploitation, so this paper reviews Wertheimer's inchoate presentation of the ideal market as a principle of fairness, attempt of Emanuel and colleagues to apply the ideal market to human subjects research, and Ballantyne's criticisms of both the ideal market and the resulting benchmark of fairness. It argues that the criticism of this particular benchmark is on point, but the rejection of the ideal market is mistaken. After presenting a complete account of the ideal market, this paper proposes a new method for applying the ideal market to human subjects research and illustrates the proposal by considering a sample case. PMID:21270474

  5. The ideal energy of classical lattice dynamics

    E-print Network

    Margolus, Norman

    2015-01-01

    We define, as local quantities, the least energy and momentum allowed by quantum mechanics and special relativity for physical realizations of some classical lattice dynamics. These definitions depend on local rates of finite-state change. In two example dynamics, we see that these rates evolve like classical mechanical energy and momentum.

  6. Christiana Honsberg Derivation of the ideal diode equation for solar cells Derivation of the Ideal Diode Equation for Photovoltaics

    E-print Network

    Honsberg, Christiana

    Christiana Honsberg Derivation of the ideal diode equation for solar cells Derivation of the Ideal Diode Equation for Photovoltaics Christiana Honsberg Basic Equations: 1. Poisson's equation of the ideal diode equation for solar cells General Procedure using the depletion approximation: Divide

  7. On controlling nonlinear dissipation in high order filter methods for ideal and non-ideal MHD

    NASA Technical Reports Server (NTRS)

    Yee, H. C.; Sjogreen, B.

    2004-01-01

    The newly developed adaptive numerical dissipation control in spatially high order filter schemes for the compressible Euler and Navier-Stokes equations has been recently extended to the ideal and non-ideal magnetohydrodynamics (MHD) equations. These filter schemes are applicable to complex unsteady MHD high-speed shock/shear/turbulence problems. They also provide a natural and efficient way for the minimization of Div(B) numerical error. The adaptive numerical dissipation mechanism consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. The numerical dissipation considered consists of high order linear dissipation for the suppression of high frequency oscillation and the nonlinear dissipative portion of high-resolution shock-capturing methods for discontinuity capturing. The applicable nonlinear dissipative portion of high-resolution shock-capturing methods is very general. The objective of this paper is to investigate the performance of three commonly used types of nonlinear numerical dissipation for both the ideal and non-ideal MHD.

  8. Nonlinear theory of ion-acoustic waves in an ideal plasma with degenerate electrons

    SciTech Connect

    Dubinov, A. E. [Russian Federal Nuclear Center, All-Russia Research Institute of Experimental Physics (Russian Federation); Dubinova, A. A. [Lobachevsky Nizhni Novgorod State University, Advanced School of General and Applied Physics (Russian Federation)

    2007-10-15

    A nonlinear theory is constructed that describes steady-state ion-acoustic waves in an ideal plasma in which the electron component is a degenerate Fermi gas and the ion component is a classical gas. The parameter ranges in which such a plasma can exist are determined, and dispersion relations for ion-acoustic waves are obtained that make it possible to find the linear ion-acoustic velocity. Analytic gas-dynamic models of ion sound are developed for a plasma with the ion component as a cold, an isothermal, or an adiabatic gas, and moreover, the solutions to the equations of all the models are brought to a quadrature form. Profiles of a subsonic periodic and a supersonic solitary wave are calculated, and the upper critical Mach numbers of a solitary wave are determined. For a plasma with cold ions, the critical Mach number is expressed by an explicit exact formula.

  9. QUANTUM CRYPTOGRAPHY QUANTUM COMPUTING

    E-print Network

    Bachoc, Christine

    QUANTUM CRYPTOGRAPHY QUANTUM COMPUTING 1. Quantum cryptography : from basic principles to practical'Optique, Orsay #12;QIPC / S4P QUANTUM CRYPTOGRAPHY A. Beveratos1, A. Villing1, F. Grosshans1, J. Wenger1, T principles of quantum key distribution (quantum cryptography)(quantum cryptography) 2. Quantum key

  10. [What criteria for an ideal antipsychotic treatment?].

    PubMed

    Bordet, R

    2015-02-01

    Antipsychotics are, by definition, drugs to treat all symptomatic dimensions of schizophrenia, even if, following the discovery of chlorpromazine, the effect assessment has been focused on the ability to reduce positive symptoms. Nevertheless, expectations of treatment are no longer limited to only support this one dimension, but integrate the need to treat negative, cognitive and affective symptoms, through long-term modulation of dopamine transmission but also non-dopaminergic pathways. Beyond symptomatic treatment, it is also necessary to have a treatment modifying the evolution course of the disease (disease modifier), acting by a long-term effect on neuropathological and neurochemical abnormalities. The limitation of long-term effect remains the issue of therapeutic observance. Moreover, this concern for efficiency should be at the cost of reduced induction of adverse effects to maximize the benefit/risk ratio. All these dimensions should the components to profile an ideal antipsychotic treatment in 2015. PMID:25638050

  11. Review of Idealized Aircraft Wake Vortex Models

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; Proctor, Fred H.; Duparcmeur, Fanny M. Limon; Jacob, Don

    2014-01-01

    Properties of three aircraft wake vortex models, Lamb-Oseen, Burnham-Hallock, and Proctor are reviewed. These idealized models are often used to initialize the aircraft wake vortex pair in large eddy simulations and in wake encounter hazard models, as well as to define matched filters for processing lidar observations of aircraft wake vortices. Basic parameters for each vortex model, such as peak tangential velocity and circulation strength as a function of vortex core radius size, are examined. The models are also compared using different vortex characterizations, such as the vorticity magnitude. Results of Euler and large eddy simulations are presented. The application of vortex models in the postprocessing of lidar observations is discussed.

  12. Ideal magnetohydrodynamic interchanges in low density plasmas

    SciTech Connect

    Huang Yimin; Goel, Deepak; Hassam, A.B. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2005-03-01

    The ideal magnetohydrodynamic equations are usually derived under the assumption V{sub A}<

  13. Quantum Quench and Prethermalization Dynamics in a Two-Dimensional Fermi Gas with Long-Range Interactions

    NASA Astrophysics Data System (ADS)

    Nessi, N.; Iucci, A.; Cazalilla, M. A.

    2014-11-01

    We study the effect of suddenly turning on a long-range interaction in a spinless Fermi gas in two dimensions. The short- to intermediate-time dynamics is described using the method of bosonization of the Fermi surface. The space-time dependence of the nonequilibrium fermion density matrix as well as the evolution after the quench of the discontinuity at the Fermi momentum of the momentum distribution are computed. We find that the asymptotic state predicted by bosonization is consistent with the existence of a prethermalization plateau, which is also predicted by a perturbative approach in terms of the fermionic degrees of freedom. The bosonized representation, however, explicitly allows for the construction of the generalized Gibbs ensemble describing the prethermalized state.

  14. Development of 275kV gas cooled type gas-insulated power transformer

    Microsoft Academic Search

    A. Kudo; T. Nishitani; T. Yoshikawa; C. T. Wan

    1993-01-01

    A world's first 275kV gas cooled type gas insulated power transformer with a low sound level ideal for urban area, which depends on SF6 gas alone for both insulation and cooling, was developed and has been put into commercial service since 1990 in Hong Kong. This paper presents the design philosophy, the principal technical items, the rating and the feature

  15. Oscillations and evolution of a hot and dense gas of flavor neutrinos: a quantum field theory study

    E-print Network

    D. Boyanovsky; C. M. Ho

    2004-04-09

    We study the time evolution of the distribution functions for hot and or degenerate gases of two flavors of Dirac neutrinos as a result of flavor mixing and dephasing. This is achieved by obtaining the time evolution of the flavor density matrix directly from quantum field theory at finite temperature and density. The time evolution features a rich hierarchy of scales which are widely separated in the nearly degenerate or relativistic cases and originate in interference phenomena between particle and antiparticle states. In the degenerate case the flavor asymmetry $\\Delta N(t)$ relaxes to the asymptotic limit $\\Delta N(\\infty)=\\Delta N(0)\\cos^2(2\\theta)$ via dephasing resulting from the oscillations between flavor modes that are not Pauli blocked, with a power law $1/t$ for $t>t_s \\approx 2 k_F/\\Delta M^2$. $k_F$ is the largest of the Fermi momenta. The distribution function for flavor neutrinos and antineutrinos as well as off-diagonal densities are obtained. Flavor particle-antiparticle pairs are produced by mixing and oscillations with typical momentum $k\\sim \\bar{M}$ the average mass of the neutrinos. An effective field theory description emerges on long time scales in which the Heisenberg operators obey a Bloch-type equation of motion valid in the relativistic and nearly degenerate cases. We find the non-equilibrium propagators and correlation functions in this effective theory and discuss its regime of validity as well as the potential corrections.

  16. Quantum field theory for the three-body constrained lattice Bose gas. II. Application to the many-body problem

    NASA Astrophysics Data System (ADS)

    Diehl, S.; Baranov, M.; Daley, A. J.; Zoller, P.

    2010-08-01

    We analyze the ground-state phase diagram of attractive lattice bosons, which are stabilized by a three-body onsite hardcore constraint. A salient feature of this model is an Ising-type transition from a conventional atomic superfluid to a dimer superfluid with vanishing atomic condensate. The study builds on an exact mapping of the constrained model to a theory of coupled bosons with polynomial interactions, proposed in a related paper [S. Diehl, M. Baranov, A. Daley, and P. Zoller, Phys. Rev. B 82, 064509 (2010).10.1103/PhysRevB.82.064509]. In this framework, we focus by analytical means on aspects of the phase diagram which are intimately connected to interactions, and are thus not accessible in a mean-field plus spin-wave approach. First, we determine shifts in the mean-field phase border, which are most pronounced in the low-density regime. Second, the investigation of the strong coupling limit reveals the existence of a “continuous supersolid,” which emerges as a consequence of enhanced symmetries in this regime. We discuss its experimental signatures. Third, we show that the Ising-type phase transition, driven first order via the competition of long-wavelength modes at generic fillings, terminates into a true Ising quantum critical point in the vicinity of half filling.

  17. Einstein's idealism and a new kind of space research

    NASA Astrophysics Data System (ADS)

    Popov, M. A.

    In 1935, Albert Einstein, Boris Podolsky and Nathan Rosen made an attempt to imagine quantum experimental nonsense or some impossible experiment (EPR-experiment) in order to justify their local realism in physics. However, in the mid-1960s, John Bell showed that it is possible to realize this kind of nonsense in laboratory. Today, when EPR-refutation of local realism is routine in modern experimental physics (Clauser and Freedman [1972]; Aspect, Dalibard and Roger [1982]; Zeilinger et al. [1998]), we must; nevertheless, remark that Albert Einstein was not always a realist. As is known, in his Special Relativitz A. Einstein introduced some pure idealistic principle which K. Godel developed in famous "Remark about the relationship between Relativity theorz and Idealistic Philosophy" (1949). Kurt Godel for the first time showed an existence of special-relativistic solipsism, assuming that objective simultaneity in experimental science "loses its objective meaning". Correspondingly, there is only subjective simultaneity, that is provable by calculations with the finite velocity of light and astronomical observations. In particular, this space solipsism means that when we observe the sun, we can see only what happend on Sun 8.33 minutes ago; in other words, we percieve only certain sensations or a certain collections of ideas of the past, but not the present. Similarly, when astronomers observe galaxies estimated to be two billion light years from the Earth, they see these galaxies as they were two billion light years ago not as they are Now. Thus, in accordance with this, we may await that in this context for some pairs of astronomical objects we cannot prove they exist NOW. Moreover, this new kind of space research could be connected with introduction of the Cognitive Dark Matter, or, what is associated with manifold of the large-scale events of the Universe as a whole which are realizing Now, beyond consciousness of the observers-humans. Because we cannot know present time in Cosmology, the Cognitive Dark Matter is Kant-like superphenomental, or transcendental "noumental process" (Noumena). To describe Transcendental Dark Matter by methods of experimental idealism is, probably, the most sursprising and profound task for new space discipline ("Space Idealism"). We may await also that some fundamental characteristics of physical Dark Matter, discovered by Ostiker, Steinhardt, Krauss and Turner (1955), can be explained by our hypothethis, because it is not impossible that the Dark Matter is a part of the Cognitive Dark Matter, contained an observer's impact, which cannot be neglected after Special Relativity.

  18. A Full Ranking for Decision Making Units Using Ideal and Anti-Ideal Points in DEA

    PubMed Central

    Barzegarinegad, A.; Jahanshahloo, G.; Rostamy-Malkhalifeh, M.

    2014-01-01

    We propose a procedure for ranking decision making units in data envelopment analysis, based on ideal and anti-ideal points in the production possibility set. Moreover, a model has been introduced to compute the performance of a decision making unit for these two points through using common set of weights. One of the best privileges of this method is that we can make ranking for all decision making units by solving only three programs, and also solving these programs is not related to numbers of decision making units. One of the other advantages of this procedure is to rank all the extreme and nonextreme efficient decision making units. In other words, the suggested ranking method tends to seek a set of common weights for all units to make them fully ranked. Finally, it was applied for different sets holding real data, and then it can be compared with other procedures. PMID:25147844

  19. A full ranking for decision making units using ideal and anti-ideal points in DEA.

    PubMed

    Barzegarinegad, A; Jahanshahloo, G; Rostamy-Malkhalifeh, M

    2014-01-01

    We propose a procedure for ranking decision making units in data envelopment analysis, based on ideal and anti-ideal points in the production possibility set. Moreover, a model has been introduced to compute the performance of a decision making unit for these two points through using common set of weights. One of the best privileges of this method is that we can make ranking for all decision making units by solving only three programs, and also solving these programs is not related to numbers of decision making units. One of the other advantages of this procedure is to rank all the extreme and nonextreme efficient decision making units. In other words, the suggested ranking method tends to seek a set of common weights for all units to make them fully ranked. Finally, it was applied for different sets holding real data, and then it can be compared with other procedures. PMID:25147844

  20. On properties of Velikhov-Chandrasekhar MRI in ideal and non-ideal plasma

    NASA Astrophysics Data System (ADS)

    Shakura, N.; Postnov, K.

    2015-04-01

    Conditions of Velikhov-Chandrasekhar magnetorotational instability (MRI) in ideal and non-ideal plasmas are examined. Linear WKB analysis of hydromagnetic axially symmetric flows shows that in the Rayleigh-unstable hydrodynamic case where the angular momentum decreases with radius, the MRI branch becomes stable, and the magnetic field suppresses the Rayleigh instability at small wavelengths. We investigate the limiting transition from hydromagnetic flows to hydrodynamic flows. The Rayleigh mode smoothly transits to the hydrodynamic case, while the Velikhov-Chandrasekhar MRI mode completely disappears without the magnetic field. The effects of viscosity and magnetic diffusivity in plasma on the MRI conditions in thin accretion discs are studied. We find the limits on the mean-free path of ions allowing MRI to operate in such discs.

  1. Faked states attack and quantum cryptography protocols

    E-print Network

    Denny, Travis

    2011-01-01

    Leveraging quantum mechanics, cryptographers have devised provably secure key sharing protocols. Despite proving the security in theory, real-world application falls short of the ideal. Last year, cryptanalysts completed an experiment demonstrating a successful eavesdropping attack on commercial quantum key distribution (QKD) systems. This attack exploits a weakness in the typical real-world implementation of quantum cryptosystems. Cryptanalysts have successfully attacked several protocols. In this paper, we examine the Kak quantum cryptography protocol and how it may perform under such attacks.

  2. Field topologies in ideal and near-ideal magnetohydrodynamics and vortex dynamics

    NASA Astrophysics Data System (ADS)

    Low, B. C.

    2015-01-01

    Magnetic field topology frozen in ideal magnetohydrodynamics (MHD) and its breakage in near-ideal MHD are reviewed in two parts, clarifying and expanding basic concepts. The first part gives a physically complete description of the frozen field topology derived from magnetic flux conservation as the fundamental property, treating four conceptually related topics: Eulerian and Lagrangian descriptions of three dimensional (3D) MHD, Chandrasekhar-Kendall and Euler-potential field representations, magnetic helicity, and inviscid vortex dynamics as a fluid system in physical contrast to ideal MHD. A corollary of these developments clarifies the challenge of achieving a high degree of the frozen-in condition in numerical MHD. The second part treats field-topology breakage centered around the Parker Magnetostatic Theorem on a general incompatibility of a continuous magnetic field with the dual demand of force-free equilibrium and an arbitrarily prescribed, 3D field topology. Preserving field topology as a global constraint readily results in formation of tangential magnetic discontinuities, or, equivalently, electric current-sheets of zero thickness. A similar incompatibility is present in the steady force-thermal balance of a heated radiating fluid subject to an anisotropic thermal flux conducted strictly along its frozen-in magnetic field in the low- ? limit. In a weakly resistive fluid the thinning of current sheets by these general incompatibilities inevitably results in sheet dissipation, resistive heating and topological changes in the field notwithstanding the small resistivity. Strong Faraday induction drives but also macroscopically limits this mode of energy dissipation, trapping or storing free energy in self-organized ideal-MHD structures. This property of MHD turbulence captured by the Taylor hypothesis is reviewed in relation to the Sun's corona, calling for a basic quantitative description of the breakdown of flux conservation in the low-resistivity limit. A cylindrical initial-boundary value problem provides specificity in the general MHD ideas presented.

  3. Blowups of ideal triangulations Definition. A blowup of an ideal triangula

    E-print Network

    Jaco, William

    that crush­ ing T along #X gives T # . PSfrag replacements (X, T ) ( # X , T # ) v # 1 v # 2 v # 3 #1 #2 #3 T1 T2 T 3 S1 S 2 S3 Blow­up Crush I AM THE WALRUS, GOO, GOO, GOO, JOOB! # = {#1 , #2 , #3} 1 #12; . Crushing triangulations along normal sur­ faces Set Up: ­ M a 3--manifold, T a triangulation (or ideal

  4. Numerical Modeling of Fractured Shale-Gas and Tight-Gas Reservoirs Using Unstructured Grids 

    E-print Network

    Olorode, Olufemi Morounfopefoluwa

    2012-02-14

    -ideal fracture geometries and coupled primary-secondary fracture interactions on reservoir performance in these unconventional gas reservoirs. This thesis provides a grid construction tool to generate high-resolution unstructured meshes using Voronoi grids...

  5. Ideal bandpasses for type Ia supernova cosmology

    SciTech Connect

    Davis, Tamara M.; Schmidt, Brian P.; Kim, Alex G.

    2005-10-24

    To use type Ia supernovae as standard candles for cosmologywe need accurate broadband magnitudes. In practice the observed magnitudemay differ from the ideal magnitude-redshift relationship either throughintrinsic inhomogeneities in the type Ia supernova population or throughobservational error. Here we investigate how we can choose filterbandpasses to reduce the error caused by both these effects. We find thatbandpasses with large integral fluxes and sloping wings are best able tominimise several sources of observational error, and are also leastsensitive to intrinsic differences in type Ia supernovae. The mostimportant feature of a complete filter set for type Ia supernovacosmology is that each bandpass be a redshifted copy of the first. Wedesign practical sets of redshifted bandpasses that are matched totypical high resistivity CCD and HgCdTe infra-red detector sensitivities.These are designed to minimise systematic error in well observedsupernovae, final designs for specific missions should also considersignal-to-noise requirements and observing strategy. In addition wecalculate how accurately filters need to be calibrated in order toachieve the required photometric accuracy of future supernova cosmologyexperiments such as the SuperNova-Acceleration-Probe (SNAP), which is onepossible realisation of the Joint Dark-Energy mission (JDEM). We considerthe effect of possible periodic miscalibrations that may arise from theconstruction of an interference filter.

  6. Molecular structure and stabilities of fumaric acid conformers: Gas phase electron diffraction (GED) and quantum-chemical studies

    NASA Astrophysics Data System (ADS)

    Vogt, Natalja; Abaev, Maxim A.; Karasev, Nikolai M.

    2011-02-01

    The molecular structure of fumaric acid was reinvestigated by the gas phase electron diffraction (GED) method because it was determined several years ago assuming the existence of one conformer only. According to MP2/cc-pVTZ predictions, the molecule has six stable conformations, and three of them, sp,sp,sp,sp (I), ap,sp,sp,sp (II) and ap,ap,sp,sp (III), with relative energies within ca. 3 kJ mol -1 should be present in detectable amounts at the experimental temperature of ca. 480 K. The best fit to the GED intensities was achieved at the approximately equal amounts of the conformers I-III. To take into account vibrational effects, the corrections to the experimental r a bond lengths ( r e - r a) were calculated using quadratic and cubic force constants from high-level ab initio calculations (MP2/cc-pVTZ). The deduced equilibrium bond lengths of the conformer II with the estimated total errors (in Å) are the following: r e(C dbnd C) = 1.331(3), r e(C sbnd C) s-trans = 1.473(3), r e(C sbnd C) s-cis = 1.479(3), r e(C sbnd O) s-trans = 1.345(3), r e(C sbnd O) s-cis = 1.344(3), r e(C dbnd O) s-trans = 1.205(3), r e(C dbnd O) s-cis = 1.204(3). The structural effects arising due to presence of the C dbnd C double bond were analysed. In comparison to the experiment, the MP2/cc-pVQZ approximation overestimates some bond lengths in fumaric acid and similar molecules by up to 0.005 Å. The rotational constants of the conformers I-III were derived from the GED equilibrium geometries.

  7. Money in Gas-Like Markets: Gibbs and Pareto Laws

    Microsoft Academic Search

    Arnab Chatterjeeand; Bikas K. Chakrabarti; S. S. Manna

    2003-01-01

    We consider the ideal-gas models of trading markets, where each agent is identified with a gas molecule and each trading as an elastic or money-conserving (two-body) collision. Unlike in the ideal gas, we introduce a saving propensity lambda of agents, such that each agent saves a fraction lambda of its money and trades with the rest. We show that the

  8. Hamiltonian description of the ideal fluid

    SciTech Connect

    Morrison, P.J. [Department of Physics and Institute for Fusion Studies, University of Texas, Austin, Texas 78712-1060 (United States)] [Department of Physics and Institute for Fusion Studies, University of Texas, Austin, Texas 78712-1060 (United States)

    1998-04-01

    The Hamiltonian viewpoint of fluid mechanical systems with few and infinite number of degrees of freedom is described. Rudimentary concepts of finite-degree-of-freedom Hamiltonian dynamics are reviewed, in the context of the passive advection of a scalar or tracer field by a fluid. The notions of integrability, invariant-tori, chaos, overlap criteria, and invariant-tori breakup are described in this context. Preparatory to the introduction of field theories, systems with an infinite number of degrees of freedom, elements of functional calculus and action principles of mechanics are reviewed. The action principle for the ideal compressible fluid is described in terms of Lagrangian or material variables. Hamiltonian systems in terms of noncanonical variables are presented, including several examples of Eulerian or inviscid fluid dynamics. Lie group theory sufficient for the treatment of reduction is reviewed. The reduction from Lagrangian to Eulerian variables is treated along with Clebsch variable decompositions. Stability in the canonical and noncanonical Hamiltonian contexts is described. Sufficient conditions for stability, such as Rayleigh-like criteria, are seen to be only sufficient in the general case because of the existence of negative-energy modes, which are possessed by interesting fluid equilibria. Linearly stable equilibria with negative energy modes are argued to be unstable when nonlinearity or dissipation is added. The energy-Casimir method is discussed and a variant of it that depends upon the notion of dynamical accessibility is described. The energy content of a perturbation about a general fluid equilibrium is calculated using three methods. {copyright} {ital 1998} {ital The American Physical Society}

  9. [Ideal family size in Arab countries].

    PubMed

    Ayad, M

    1987-01-01

    This study on the ideal family size in Arab countries, is based on the findings of the World Fertility Survey led in 8 Arab countries (Egypt, 1980; Jordan, 1976; Morocco, 1980; Mauritania, 1981; Sudan, 1979; Syria, 1978; Tunisia, 1978; and Arab Republic of Yemen, 1979). During these surveys, a questionnaire was presented to a specimen of 2,500 to 8,500 women, 1st to married and fertile women, then to childless or pregnant women. The study of the responses shows that a great majority of Arab women desire a large family. Less than 20% of them do not want to have another child in the future in Mauritania, Sudan, and Yemen; between 37% and 53% in the 5 other countries. The total number of children wanted is 4.9 in Morocco, 5.4 in Yemen, 6.1 in Sudan, 6.3 in Jordan and Syria, and 8.7 in Mauritania. Women prefer to have boys rather than girls. In Egypt and Tunisia, respectively, 83% and 66% do not want to have another child when there are as many boys as girls in the family. As expected, the more children a woman has, the less she wants to have another one. The more women use contraception and modern contraceptives, the less they want another child. Of the women who do not want another child, 67% are using contraception in Tunisia, 65% in Egypt, 50% in Syria, Morocco, and Jordan, but 25% in Sudan, 17% in Yemen, and 15% in Mauritania. The transition from natural fertility to planned fertility is very slow in Mauritania, Yemen, and Sudan, while Syria and Jordan present the beginning of an evolution. The decline of fertility is faster in Egypt, Tunisia, and Morocco. In Arab countries, the weight of the traditional patriarchal family, and the lack of education and social opportunities for women is slowing down demographic transition. PMID:12179478

  10. Idealized computational models for auditory receptive fields.

    PubMed

    Lindeberg, Tony; Friberg, Anders

    2015-01-01

    We present a theory by which idealized models of auditory receptive fields can be derived in a principled axiomatic manner, from a set of structural properties to (i) enable invariance of receptive field responses under natural sound transformations and (ii) ensure internal consistency between spectro-temporal receptive fields at different temporal and spectral scales. For defining a time-frequency transformation of a purely temporal sound signal, it is shown that the framework allows for a new way of deriving the Gabor and Gammatone filters as well as a novel family of generalized Gammatone filters, with additional degrees of freedom to obtain different trade-offs between the spectral selectivity and the temporal delay of time-causal temporal window functions. When applied to the definition of a second-layer of receptive fields from a spectrogram, it is shown that the framework leads to two canonical families of spectro-temporal receptive fields, in terms of spectro-temporal derivatives of either spectro-temporal Gaussian kernels for non-causal time or a cascade of time-causal first-order integrators over the temporal domain and a Gaussian filter over the logspectral domain. For each filter family, the spectro-temporal receptive fields can be either separable over the time-frequency domain or be adapted to local glissando transformations that represent variations in logarithmic frequencies over time. Within each domain of either non-causal or time-causal time, these receptive field families are derived by uniqueness from the assumptions. It is demonstrated how the presented framework allows for computation of basic auditory features for audio processing and that it leads to predictions about auditory receptive fields with good qualitative similarity to biological receptive fields measured in the inferior colliculus (ICC) and primary auditory cortex (A1) of mammals. PMID:25822973

  11. Idealized Computational Models for Auditory Receptive Fields

    PubMed Central

    Lindeberg, Tony; Friberg, Anders

    2015-01-01

    We present a theory by which idealized models of auditory receptive fields can be derived in a principled axiomatic manner, from a set of structural properties to (i) enable invariance of receptive field responses under natural sound transformations and (ii) ensure internal consistency between spectro-temporal receptive fields at different temporal and spectral scales. For defining a time-frequency transformation of a purely temporal sound signal, it is shown that the framework allows for a new way of deriving the Gabor and Gammatone filters as well as a novel family of generalized Gammatone filters, with additional degrees of freedom to obtain different trade-offs between the spectral selectivity and the temporal delay of time-causal temporal window functions. When applied to the definition of a second-layer of receptive fields from a spectrogram, it is shown that the framework leads to two canonical families of spectro-temporal receptive fields, in terms of spectro-temporal derivatives of either spectro-temporal Gaussian kernels for non-causal time or a cascade of time-causal first-order integrators over the temporal domain and a Gaussian filter over the logspectral domain. For each filter family, the spectro-temporal receptive fields can be either separable over the time-frequency domain or be adapted to local glissando transformations that represent variations in logarithmic frequencies over time. Within each domain of either non-causal or time-causal time, these receptive field families are derived by uniqueness from the assumptions. It is demonstrated how the presented framework allows for computation of basic auditory features for audio processing and that it leads to predictions about auditory receptive fields with good qualitative similarity to biological receptive fields measured in the inferior colliculus (ICC) and primary auditory cortex (A1) of mammals. PMID:25822973

  12. High Performance Quantum Computing

    E-print Network

    Simon J. Devitt; William J. Munro; Kae Nemoto

    2008-10-14

    The architecture scalability afforded by recent proposals of a large scale photonic based quantum computer, utilizing the theoretical developments of topological cluster states and the photonic chip, allows us to move on to a discussion of massively scaled Quantum Information Processing (QIP). In this letter we introduce the model for a secure and unsecured topological cluster mainframe. We consider the quantum analogue of High Performance Computing, where a dedicated server farm is utilized by many users to run algorithms and share quantum data. The scaling structure of photonics based topological cluster computing leads to an attractive future for server based QIP, where dedicated mainframes can be constructed and/or expanded to serve an increasingly hungry user base with the ideal resource for individual quantum information processing.

  13. Quantum Electron Star

    E-print Network

    Allais, Andrea

    We construct and probe a holographic description of a state of matter that results from coupling a Fermi liquid to a relativistic conformal field theory (CFT). The bulk solution is described by a quantum gas of fermions ...

  14. Quantum chemical approach for condensed-phase thermochemistry (II): Applications to formation and combustion reactions of liquid organic molecules

    NASA Astrophysics Data System (ADS)

    Ishikawa, Atsushi; Nakai, Hiromi

    2015-03-01

    The harmonic solvation model (HSM), which was recently developed for evaluating condensed-phase thermodynamics by quantum chemical calculations (Nakai and Ishikawa, 2014), was applied to formation and combustion reactions of simple organic molecules. The conventional ideal gas model (IGM) considerably overestimated the entropies of the liquid molecules. The HSM could significantly improve this overestimation; mean absolute deviations for the Gibbs energies of the formation and combustion reactions were (49.6, 26.7) for the IGM and (9.7, 5.4) for the HSM in kJ/mol.

  15. Non-ideal Effects in Streaming Bi-Dust Acoustic Instability

    SciTech Connect

    Puerta, J. [Departamento de Fisica, Universidad Simon Bolivar, Apdo. 89000 (Venezuela); Castro, E.; Martin, P.; Arias, H. [Caracas (Venezuela)

    2006-12-04

    Streaming dust acoustic instabilities in the presence of a dust beam in a weakly non-ideal dusty plasma have been studied considering a new form for the state equation with two kind of grains. Fluctuating charging effects are not considered in this work. Homogeneous dust-acoustic waves (DAWS) are studied for a perturbed plasma in a very low frequency regime, where dusty plasmas support new kind of waves and instabilities due to the dust collective dynamics. In this analysis a fluid model is used and electrons and ions are determined by their Boltzmann factors in order to find an adequate dispersion relation, which has several parameters depending of the state equation constants. In this paper we use the state equation structured by Ree and Hoover using Pade approximant for a hard-sphere gas in the form P = nT 1 + nb{sub 0} (1 + a{sub 1}b{sub 0}n + a{sub 2}b{sub 0}{sup 2}n{sup 2}/1 - b{sub 1}b{sub 0}n + b{sub 2}b{sub 0}{sup 2}n{sup 2}) is applied, where b0 is calculated by the second virial term for the hard-core model. This type of equation is more accurate than other expressions and easier to manipulate. Comparisons between the ideal and non ideal cases is performed. Constants a1, a2, b1, b2, are calculated with the Pade method. The onset of the instability and also the growth rates are studied in function of relevant parameters of the system as the radius of the grains and their densities. In our analysis the instability region for non ideal plasma is compared with that of the ideal ones.

  16. The Quantum World of Ultra-Cold Atoms and Light - Book 1: Foundations of Quantum Optics

    NASA Astrophysics Data System (ADS)

    Gardiner, Crispin; Zoller, Peter

    2014-03-01

    Abstract The Table of Contents is as follows: * I - THE PHYSICAL BACKGROUND * 1. Controlling the Quantum World * 1.1 Quantum Optics * 1.2 Quantum Information * 2. Describing the Quantum World * 2.1 Classical Stochastic Processes * 2.2. Theoretical Quantum Optics * 2.3. Quantum Stochastic Methods * 2.4. Ultra-Cold Atoms * II - CLASSICAL STOCHASTIC METHODS * 3. Physics in a Noisy World * 3.1. Brownian Motion and the Thermal Origin of Noise * 3.2. Brownian Motion, Friction, Noise and Temperature * 3.3. Measurement in a Fluctuating System * 4. Stochastic Differential Equations * 4.1. Ito Stochastic Differential Equation * 4.2. The Fokker-Planck Equation * 4.3. The Stratonovich Stochastic Differential Equation * 4.4. Systems with Many Variables * 4.5. Numerical Simulation of Stochastic Differential Equations * 5. The Fokker-Planck Equation * 5.1. Fokker-Planck Equation in One Dimension * 5.2. Eigenfunctions of the Fokker-Planck Equation * 5.3. Many-Variable Fokker-Planck Equations * 6. Master Equations and Jump Processes * 6.1. The Master Equation * 7. Applications of Random Processes * 7.1. The Ornstein-Uhlenbeck Process * 7.2. Johnson Noise * 7.3. Complex Variable Oscillator Processes * 8. The Markov Limit * 8.1. The White Noise Limit * 8.2. Interpretation and Generalizations of the White Noise Limit * 8.3. Linear Non-Markovian Stochastic Differential Equations * 9. Adiabatic Elimination of Fast Variables * 9.1 Slow and Fast Variables * 9.2. Other Applications of the Adiabatic Elimination Method * III - FIELDS, QUANTA AND ATOMS * 10. Ideal Bose and Fermi Systems * 10.1. The Quantum Gas * 10.2. Thermal States * 10.3. Fluctuations in the Ideal Bose Gas * 10.4. Bosonic Quantum Gaussian Systems * 10.5. Coherent States * 10.6. Fluctuations in Systems of Fermions * 10.7. Two-Level Systems and Pauli Matrices * 11. Quantum Fields * 11.1 Kinds of Quantum Field * 11.2 Coherence and Correlation Functions * 12. Atoms, Light and their Interaction * 12.1. Interaction with the Quantized Radiation Field * 12.2. Decay of an Excited Atom * 12.3. The Two-Level Atom in a Strong Classical Driving Field * 12.4. Interaction of a Two-Level Atom with a Single Mode * IV - QUANTUM STOCHASTIC PROCESSES * 13. Quantum Markov Processes * 13.1. Two-Level Atom in a Finite-Temperature Electromagnetic Field * 13.2. Derivation of theMaster Equation * 13.3. More General Heat Baths * 13.4. Quantum Correlation Functions and Spectra * 14. Applications of the Master Equation * 14.1. A Two-Level Atom Interacting with a Thermal Heat Bath * 14.2. The Two-Level Atom Driven by a Coherent Light Field * 14.3. Master Equations for Harmonic Oscillator Systems * 14.4. A Simple Model of Laser Cooling * V - PHASE SPACE METHODS * 15. Phase Space Representations for Bosons * 15.1. The Quantum Characteristic Function * 15.2. Phase Space Representations of the Density Operator * 16. Wigner Function Methods * 16.1. Operator Correspondences and Equations of Motion * 16.2. Damped and Driven Systems * 16.3. The Wigner Distribution Function f (x, p) * 16.4. Quantum Fluctuations in Equations of Motion * 17. P-Function Methods * 17.1. Introduction * 17.2. Artificial Neural Networks * 17.3. Clinical Example * VI - QUANTUM MEASUREMENT THEORY * 18. Foundations and Formalism of Quantum Measurement * 18.1. Formulations of Quantum Mechanics * 18.2. Modelling a Measurement-Tracks in a Cloud Chamber * 18.3. Formal Quantum Measurement Theory * 18.4. Multitime Measurements * 19. Continuous Measurements * 19.1. Photon Counting * 19.2. Wavefunction Interpretation of Continuous Measurement * 19.3. Application to Matter Wave Interference * 19.4. Damping of Quantum Coherence * 19.5. The Emergence of the oscopic World * 20. The Quantum Zeno Effect * 20.1. Theoretical Basis for the Quantum Zeno Effect * 20.2. A Quantum Model of Trapped Atoms * 20.3. Quantum Zeno Effect for a Bose-Einstein Condensate * References * Author Index * Subject Index

  17. Modeling Gas-Grain Chemistry with Quantum Chemical Cluster Calculations. I. Heterogeneous Hydrogenation of CO and H2CO on Icy Grain Mantles

    NASA Astrophysics Data System (ADS)

    Woon, David E.

    2002-04-01

    Formaldehyde (H2CO) and methanol (CH3OH) are thought to be produced in the interstellar medium by the successive hydrogenation of carbon monoxide (CO) on grain surfaces. In the gas phase, the steps in which H adds to CO and H2CO possess modest barriers and are too inefficient to account for the observed abundances. Recent laboratory work has confirmed that formaldehyde and methanol are formed when H atoms are deposited on CO ice at 12 K. The present study employs ab initio quantum chemical calculations to investigate the impact of water ice on the sequential hydrogenation of CO. The most favorable pathway is CO-->HCO (formyl radical)-->H2CO-->CH3O (methoxy radical)-->CH3OH. There is sufficient reaction energy in the final step to fragment CH3OH into methyl and hydroxyl radicals, which can be hydrogenated to yield methane and water, as observed in the experimental work. The emphasis here was on the two steps with barriers, H+CO and H+H2CO, with both addition and abstraction considered for the latter. Calculations with up to four explicit water molecules were performed, as well as further modeling to incorporate bulk effects. While ice was found to have a nearly negligible impact on H+CO-->HCO, it modestly enhances the addition reaction H+H2CO-->CH3O and hinders the abstraction reaction H+H2CO-->H2+HCO. The deuterium-substituted reactions D+CO-->DCO and D+H2CO-->CDH2O were found to be slightly favored over the corresponding H reactions, particularly in the latter case. Overall, the energetics are not favorable: water ice is evidently not a good catalytic substrate for H+CO or H+H2CO addition reactions at very cold temperatures.

  18. Measurable Control System Security through Ideal Driven Technical Metrics

    Microsoft Academic Search

    Miles McQueen; Wayne Boyer; Sean McBride; Marie Farrar; Zachary Tudor

    2008-01-01

    The Department of Homeland Security National Cyber Security Division supported development of a small set of security ideals as a framework to establish measurable control systems security. Based on these ideals, a draft set of proposed technical metrics was developed to allow control systems owner-operators to track improvements or degradations in their individual control systems security posture. The technical metrics

  19. CLONES FROM IDEALS MATHIAS BEIGLBOCK, MARTIN GOLDSTERN, LUTZ HEINDORF,

    E-print Network

    Beiglböck, Mathias

    CLONES FROM IDEALS MATHIAS BEIGLB¨OCK, MARTIN GOLDSTERN, LUTZ HEINDORF, AND MICHAEL PINSKER Abstract. On an infinite base set X, every ideal of subsets of X can be associated with the clone of those of such clones in the clone lattice. 0. Introduction 0.1. Clones. Let X be an infinite set and denote the set

  20. Coefficient Ideals in and Blowups of a Commutative Noetherian ...

    E-print Network

    Section 3 studies M-primary ideals in a quasi-unmixed (i.e., formally equidimensional, in the. terminology of [Mt2 ... for a maximal ideal of R of height two and x2y5 ? (I2 : I) ? I, so I is not Ratliff–Rush. The .... We refer the reader to [

  1. Idealization in Chemistry: Pure Substance and Laboratory Product

    NASA Astrophysics Data System (ADS)

    Fernández-González, Manuel

    2013-07-01

    This article analyzes the concept of idealization in chemistry and the role played by pure substance and laboratory product. This topic has evident repercussions in the educational contexts that are applied to the science classroom, which are highlighted throughout the text. A common structure for knowledge construction is proposed for both physics and chemistry with particular emphasis on the relations between two of the levels: the ideal level and the quasi-ideal level. The ideal level is crucial for operations related to theoretical constructions and explanations, whereas the quasi-ideal level is of special importance in the verification of propositions. In chemistry, the ideal level and the quasi-ideal level include the entities, pure substance and laboratory product, respectively. This article provides an in-depth discussion of the concept of pure substance, an idealized entity whose empirical correlate is laboratory product. The study of the link between the two is a very significant part of the problem of the relations between theory and reality in chemistry. These entities are used to analyze and interpret different situations and contexts in research as well as teaching. The article concludes by using classroom examples to illustrate the didactic implications of the issues addressed.

  2. Teachers' ethnotheories of the ‘ideal student’ in five western cultures

    Microsoft Academic Search

    Sara Harkness; Marjolijn Blom; Alfredo Oliva; Ughetta Moscardino; Piotr Olaf Zylicz; Moises Rios Bermudez; Xin Feng; Giovanna Axia; Charles M. Super

    2007-01-01

    This paper explores teachers' ethnotheories of the ‘ideal student’ in five western societies: Italy, The Netherlands, Poland, Spain, and the US. Quantitative and qualitative methods are used to derive culture?specific profiles of the ‘ideal student’ as described by kindergarten and primary school teachers in semi?structured interviews (sample n's = 12 to 21). Discriminant function analysis shows that teachers' descriptor profiles

  3. Extension of the Piecewise Parabolic Method to Multidimensional Ideal Magnetohydrodynamics

    Microsoft Academic Search

    Wenlong Dai; Paul R. Woodward

    1994-01-01

    An extension of the piecewise parabolic method to treat multidimensional ideal magnetohydrodynamical equations is presented in this paper. The multidimensional scheme is constructed from a one-dimensional functioning code based on the dimensional splitting method originally suggested by Strang. The functioning code is built upon a nonlinear Riemann solver for ideal MHD equations recently developed by the authors. The correctness of

  4. Women's and Men's Ratings of Their Own and Ideal Speech.

    ERIC Educational Resources Information Center

    Kramer, Cheris

    1978-01-01

    A study comparing women's and men's ratings of their own and ideal speech showed that a greater number of speech characteristics of males differed from the speech characteristics of the ideal speaker. Women are advised to consider the desirable characteristics associated with female speech before altering their speech by such means as…

  5. UNIFORM APPROXIMATION OF ABHYANKAR VALUATION IDEALS IN SMOOTH FUNCTION FIELDS

    E-print Network

    UNIFORM APPROXIMATION OF ABHYANKAR VALUATION IDEALS IN SMOOTH FUNCTION FIELDS LAWRENCE EIN, ROBERT that the valuation ideals of a rank one Abhyankar valuation centered at a smooth point of a complex algebraic variety be a rank one valuation centered on R. Recall that this is equivalent to asking that Å¡ be an R

  6. Games and the Impossibility of Realizable Ideal Functionality

    E-print Network

    Paris-Sud XI, Université de

    Games and the Impossibility of Realizable Ideal Functionality Michael Backes1 , Anupam Datta2 in a variety of ways, such as a condition involving a game against an attacker, construction of an ideal functionality, or a list of properties that must hold in the face of attack. While game conditions are widely

  7. Sadi Carnot's Ingenious Reasoning of Ideal Heat Engine Reversible Cycles

    E-print Network

    Kostic, Milivoje M.

    Sadi Carnot's Ingenious Reasoning of Ideal Heat Engine Reversible Cycles MILIVOJE M. KOSTIC was not noticed at his time, when his ingenious reasoning of ideal heat engine reversible cycles is not fully presented here. Key Words: Sadi Carnot, heat engine, reversible process, Thermodynamic temperature, entropy

  8. Modeling the assembly of compliant, non-ideal parts

    Microsoft Academic Search

    Minho Chang; David C. Gossard

    1997-01-01

    All manufactured parts and tooling have unavoidable variations from their nominal shapes. During assembly, compliant parts are further deformed by the relatively rigid assembly tooling. Lack of knowledge regarding variations and deformations often results in expensive problems. Since most current computer-aided design (CAD) systems today are based on ideally sized, ideally located, and rigid geometry, they are unable to model

  9. Allylic alcohols: ideal radical allylating agents?

    PubMed

    Debien, Laurent; Quiclet-Sire, Béatrice; Zard, Samir Z

    2015-05-19

    Radical allylations represent effective routes to various alkenes, but to date they have relied chiefly on organostannane derivatives and still suffer from significant limitations with respect to the substitution pattern of the starting allylating agent. Indeed, while substituents at the ?-position relative to the radical leaving group are well-tolerated, introduction of ?-substituents induces a major complication due to the rapid and usually irreversible isomerization of the starting allylating agents. Although a number of research groups have made substantial efforts to develop heavy-metal-free radical allylations, methods compatible with ?-substitution of the allylating agent are still scarce. Furthermore, quite a few systems are limited by the relative inaccessibility of the substrates. This Account summarizes our sustained efforts regarding the development of allylic alcohols into "ideal" radical allylating agents and presents published as well as some unpublished results. The systems we have developed combine the use of readily available xanthates and allylic alcohol derivatives under metal-free conditions to furnish not only alkenes but also aldehydes and saturated and unsaturated ketones through the virtually unprecedented homolytic cleavage of the normally strong C-O or C-C bond. The former route hinges on first converting the allylic alcohol into a 2-fluoro-6-pyridoxy derivative by reacting the corresponding alcoholate with 2,6-difluoropyridine, while the latter relies on attaching a cumyl group to the carbon bearing the free allylic alcohol. Either substrate is then exposed to the action of a suitable xanthate in the presence of a stoichiometric amount of a peroxide, usually lauroyl peroxide (DLP) in refluxing ethyl acetate or di-tert-butyl peroxide (TBHP) in refluxing chlorobenzene for the more difficult cases. Even though C-O or C-C bond homolysis leads to a stabilized 2-fluoro-6-pyridinyloxyl radical or a cumyl radical, respectively, the ?-scission in both cases is relatively slow and at the lower limit of useful elementary radical steps. The kinetic barrier of the fragmentation can nevertheless be overcome because of the long relative lifetime of radicals generated by the degenerate transfer of the xanthate group, and this is a key element for success. This novel technology offers numerous advantages. The starting activated allylic alcohol derivatives are readily accessible in two steps from aldehydes or ketones. They can also be obtained by base-induced opening of epoxides. Numerous functional groups are tolerated under the mild reaction conditions for the radical addition-elimination, as nicely illustrated by over 150 examples of radical allylations, not all of which can be included in the present Account. In addition, substitution at both the ?- and ?-positions of the allylating agent is possible, a rare feature in this area. PMID:25905563

  10. Interacting Ions in Biophysics: Real is not Ideal

    PubMed Central

    Eisenberg, Bob

    2013-01-01

    Ions in water are important throughout biology, from molecules to organs. Classically, ions in water were treated as ideal noninteracting particles in a perfect gas. Excess free energy of each ion was zero. Mathematics was not available to deal consistently with flows, or interactions with other ions or boundaries. Nonclassical approaches are needed because ions in biological conditions flow and interact. The concentration gradient of one ion can drive the flow of another, even in a bulk solution. A variational multiscale approach is needed to deal with interactions and flow. The recently developed energetic variational approach to dissipative systems allows mathematically consistent treatment of the bio-ions Na+, K+, Ca2+, and Cl? as they interact and flow. Interactions produce large excess free energy that dominate the properties of the high concentration of ions in and near protein active sites, ion channels, and nucleic acids: the number density of ions is often >10 M. Ions in such crowded quarters interact strongly with each other as well as with the surrounding protein. Nonideal behavior found in many experiments has classically been ascribed to allosteric interactions mediated by the protein and its conformation changes. The ion-ion interactions present in crowded solutions—independent of conformation changes of the protein—are likely to change the interpretation of many allosteric phenomena. Computation of all atoms is a popular alternative to the multiscale approach. Such computations involve formidable challenges. Biological systems exist on very different scales from atomic motion. Biological systems exist in ionic mixtures (like extracellular and intracellular solutions), and usually involve flow and trace concentrations of messenger ions (e.g., 10?7 M Ca2+). Energetic variational methods can deal with these characteristic properties of biological systems as we await the maturation and calibration of all-atom simulations of ionic mixtures and divalents. PMID:23663828

  11. Room-Temperature Quantum Cloning Machine with Full Coherent Phase

    E-print Network

    Wang, Wei Hua

    Room-Temperature Quantum Cloning Machine with Full Coherent Phase Control in Nanodiamond Yan to the classical world, an unknown quantum state cannot be cloned ideally, as stated by the no-cloning theorem. However, it is expected that approximate or probabilistic quantum cloning will be necessary for different

  12. Imaging vasculature and lymphatic flow in mice using quantum dots.

    PubMed

    Ballou, Byron; Ernst, Lauren A; Andreko, Susan; Fitzpatrick, James A J; Lagerholm, B Christoffer; Waggoner, Alan S; Bruchez, Marcel P

    2009-01-01

    Quantum dots are ideal probes for fluorescent imaging of vascular and lymphatic tissues. On injection into appropriate sites, red- and near-infrared-emitting quantum dots provide excellent definition of vasculature, lymphoid organs, and lymph nodes draining both normal tissues and tumors. We detail methods for use with commercially available quantum dots and discuss common difficulties. PMID:19685300

  13. Two Quantum Polytropic Cycles

    NASA Astrophysics Data System (ADS)

    Arias-Hernández, L. A.; Morales-Serrano, A. F.

    2002-11-01

    In this work we follow the Bender et al paper [1] to study the quantum analogues of the Stirling and Ericsson polytropic cycles. In the context of the classical thermodynamics, the Stirling and Ericsson cycles correspond to reversible heat engines with two isothermal processes joined by two polytropic branches which occur in a device called regenerator. If this device is an ideal one, the efficiency of these cycles is the Carnot efficiency. Here, we introduce the quantum analogues of the Stirling and Ericsson cycles, the first one based on a double square potential well with a finite potential barrier, since in this system the tunnel effect could be the analogue to the regeneration classical process, therefore the isochoric quantum branches would really correspond to an internal energy storage, and the last one with an unknown system where the isobaric quantum processes don't induce changes in its quantum state. With these systems the quantum engines have cycles consisting of polytropic and isothermal quantum processes analogues to the corresponding classical processes. We show that in both cases the quantum cycles have an efficiency given by ?CQM = 1 - EC/EH, which is the same expression for the quantum analogue of the Carnot cycle studied by Bender.

  14. Genetic and Environmental Influences on Thin-Ideal Internalization

    PubMed Central

    Suisman, Jessica L.; O’Connor, Shannon M.; Sperry, Steffanie; Thompson, J. Kevin; Keel, Pamela K.; Burt, S. Alexandra; Neale, Michael; Boker, Steven; Sisk, Cheryl; Klump, Kelly L.

    2012-01-01

    Objective Current research on the etiology of thin-ideal internalization focuses on psychosocial influences (e.g., media exposure). The possibility that genetic influences also account for variance in thin-ideal internalization has never been directly examined. This study used a twin design to estimate genetic effects on thin-ideal internalization and examine if environmental influences are primarily shared or nonshared in origin. Method Participants were 343 post-pubertal female twins (ages 12–22; M=17.61) from the Michigan State University Twin Registry. Thin-ideal internalization was assessed using the Sociocultural Attitudes toward Appearance Questionniare-3. Results Twin modeling suggested significant additive genetic and nonshared environmental influences on thin-ideal internalization. Shared environmental influences were small and non-significant. Discussion Although prior research focused on psychosocial factors, genetic influences on thin-ideal internalization were significant and moderate in magnitude. Research is needed to investigate possible interplay between genetic and nonshared environmental factors in the development of thin-ideal internalization. PMID:23034902

  15. The ideal strength of iron in tension and shear

    SciTech Connect

    Clatterbuck, D.M.; Chrzan, D.C.; Morris, Jr., J.W.

    2002-12-01

    The ideal strength of a material is the stress at which the lattice itself becomes unstable and, hence, sets a firm upper bound on the mechanical strength the material can have. The present paper includes an ab-initio calculation of the ideal shear strength of Fe. It is, to our knowledge, the first such computation for any ferromagnetic material. The paper also elaborates on our earlier calculation of the ideal tensile strength of Fe by studying the effects of strains which break the tetragonal symmetry. The strengths were calculated using the Projector Augmented Wave Method within the framework of density functional theory and the generalized gradient approximation. In <001> tension the ideal strength is determined by an elastic instability of the ferromagnetic phase along the ''Bain'' strain path from bcc to fcc. An <001> tensile strain also leads to instability with respect to transformation into a face centered orthorhombic structure, and to various magnetic instabilities. However, these are encountered at larger strains and, thus, do not affect the ideal strength. We also investigated the ideal shear strength of bcc iron in two prominent shear systems, <111>{l_brace}112{r_brace} and <111>{l_brace}110{r_brace}. In both shear systems the ideal strength is determined by the body centered tetragonal structure that defines a nearby saddle point on the energy surface. The ideal shear strengths are thus very similar, though they are not identical since the two shears follow slightly different strain paths from bcc to bct. We investigated the magnetic instabilities encountered during <111>{l_brace}112{r_brace} shear. These instabilities do not appear until the strain is significantly greater than the instability strain of the ferromagnetic crystal. Hence while Fe exhibits some novel effects due to magnetism, they do not affect the ideal strength, which is determined by the same elastic instabilities that determine the strengths of most other bcc metals.

  16. Quantum Formalism: Brief Epistemological Considerations

    E-print Network

    Helen Lynn; Michele Caponigro

    2006-10-26

    We argue about a conceptual approach to quantum formalism. Starting from philosophical conjectures (Platonism, Idealism and Realism) as basic ontic elements (namely: math world, data world, and state of matter), we will analyze the quantum superposition principle. This analysis bring us to demonstrate that the basic assumptions affect in different ways:(a) the general problem of the information and computability about a system, (b) the nature of the math tool utilized and (c) the correspondent physical reality.

  17. Left-Ideals, Dirac Fermions and SU(2)-Flavour

    E-print Network

    F. M. C. Witte

    2007-07-17

    In this paper I reconsider the use of the left ideals of the even-grade subalgebra of spacetime algebra to describe fermionic excitations. When interpreted as rotors the general elements of an even-grade left-ideal describe massless particles in chiral flavour doublets. To study the application of these ideas to the standard Dirac formalism I construct a $2 \\times 2$-matrix representation with bivector insertions for the Dirac algebra. This algebra has four ideals, and this approach clarifies how the identification of Dirac $\\g_{\\mu}$-matrices with orthonormal basisvectors ${\\bf e}_{\

  18. The molecular structure of tris-2,2,6,6-tetramethyl-heptane-3,5-dione aluminium: gas-phase electron diffraction, quantum chemical calculations and X-ray crystallography

    Microsoft Academic Search

    N. V. BelovaB; B. Dalhus; G. V. Girichev; N. I. Giricheva; A. Haaland; N. P. Kuzmima; T. A. Zhukova

    2011-01-01

    The molecular structure of tris-2,2,6,6-tetramethyl-heptane-3,5-dione aluminium, or Al(thd)3, has been determined by quantum chemical (DFT) calculations, X-ray crystallography and gas-phase electron diffraction monitored\\u000a by mass spectrometry (GED\\/MS). The DFT calculations yield an equilibrium structure of D\\u000a 3 symmetry. The space group imposes no on the molecule in the crystalline phase. Nevertheless, the molecule structure obtained\\u000a by X-ray crystallography has close

  19. Molecular structure and internal rotation of CF? group of methyl trifluoroacetate: gas electron diffraction, microwave spectroscopy, and quantum chemical calculation studies.

    PubMed

    Kuze, Nobuhiko; Ishikawa, Atsushi; Kono, Maho; Kobayashi, Takayuki; Fuchisawa, Noriyuki; Tsuji, Takemasa; Takeuchi, Hiroshi

    2015-03-01

    The molecular structure of methyl trifluoroacetate (CF3COOCH3) has been determined by gas electron diffraction (GED), microwave spectroscopy (MW), and quantum chemical calculations (QC). QC study provides the optimized geometries and force constants of the molecule. They were used to estimate the structural model for GED study and to calculate the vibrational corrections for GED and MW data. In addition, potential energy curves for the internal rotations of CF3 and CH3 groups have been calculated for anti (dihedral angle of ?(CCOC) is 180°) and syn (?(CCOC) = 0°) conformers of methyl trifluoroacetate. Both the GED and MW data revealed the existence of the anti conformer. Molecular constants determined by MW are A0 = 3613.4(3) MHz, B0 = 1521.146(8) MHz, C0 = 1332.264(9) MHz, ?J = 0.09(2) kHz, and ?JK = 0.23(6) kHz. The GED data were well-reproduced by the analysis in which a large-amplitude motion of the CF3 group was taken into account. The barrier of the internal rotation of the CF3 group was determined to be V3 = 2.3(4) kJ?mol(-1), where V3 is the potential coefficient of the assumed potential function, V(?) = (V3/2)(1 - cos?3?), and ? is a rotational angle for the CF3 group. The values of geometrical parameters (re structure) of the anti conformer of CF3COOCH3 are r((O?)C-O) = 1.326(6) Å, r(O-CH3) = 1.421(4) Å, r(C-H(in-plane)) = 1.083(14) Å, r(C-H(out-of-plane)) = 1.087(14) Å, r(C?O) = 1.190(7) Å, r(C-C) = 1.533(4) Å, r(C-F(in-plane)) = 1.319(4) Å, r(C-F(out-of-plane)) = 1.320(6) Å, ?COC = 116.3(5)°, ?OCH(in-plane) = 105.2° (fixed), ?OCH(out-of-plane) = 110.0° (fixed), ?O?CC = 123.7° (fixed), ?O-CC = 111.2(5)°, ?OCO = 125.2(5)°, ?CCF = 110.1(3)°, and OCCF (out-of-plane dihedral angles) = ± 121.5(1)°. Numbers in parentheses are three times the standard deviations of the data fit. PMID:25437246

  20. LaRC results on nuclear pumped noble gas lasers

    Microsoft Academic Search

    R. J. Deyoung

    1979-01-01

    The recent experiment and theoretical results obtained for noble gas nuclear laser systems are presented. It is shown that the noble gas lasers are among the easiest systems to pump by nuclear excitation and as a result, all of the noble gases except He have lased under nuclear excitation. The noble gas systems are not ideal for high-power applications but

  1. Approaching the ideal elastic limit of metallic glasses

    E-print Network

    Tian, Lin

    The ideal elastic limit is the upper bound to the stress and elastic strain a material can withstand. This intrinsic property has been widely studied for crystalline metals, both theoretically and experimentally. For ...

  2. Wittgenstein's Philosophy of Mathematics Ethics in German Idealism

    E-print Network

    in the Islamic World Philosophy of Art Philosophy of Cognitive Science Philosophy of Education EducationKant Aesthetics Wittgenstein's Philosophy of Mathematics Ethics in German Idealism Social of Historical Capital Ottoman Paleography Turkish Folk Literature History and Technology Philosophy

  3. Some remarks on non-commutative principal ideal rings

    E-print Network

    Sylvain Carpentier; Alberto De Sole; Victor G. Kac

    2013-05-02

    We prove some algebraic results on the ring of matrix differential operators over a differential field in the generality of non-commutative principal ideal rings. These results are used in the theory of non-local Poisson structures.

  4. Incorporating demand shifters in the Almost Ideal demand system

    Microsoft Academic Search

    Julian M. Alston; James A. Chalfant; Nicholas E. Piggott

    2001-01-01

    Intercepts of share equations generally include demand shift variables. In the Almost Ideal demand system and related models, this results in estimates that depend on units of measurement. Solutions to this problem are identified and discussed.

  5. Hadamard ideals and Hadamard matrices with two circulant cores

    E-print Network

    Seberry, Jennifer

    Hadamard ideals and Hadamard matrices with two circulant cores Ilias S. Kotsireas a,1, , Christos address: ikotsire@wlu.ca (Ilias S. Kotsireas). 1 Supported in part by a grant from the Research Office

  6. Hadamard ideals and Hadamard matrices with two circulant cores

    E-print Network

    Seberry, Jennifer

    Hadamard ideals and Hadamard matrices with two circulant cores Ilias S. Kotsireas a,1, , Christos, ON N2L 3C5, Canada Email address: ikotsire@wlu.ca (Ilias S. Kotsireas). 1 Supported in part by a grant

  7. Hadamard ideals and Hadamard matrices with circulant core

    E-print Network

    Seberry, Jennifer

    Hadamard ideals and Hadamard matrices with circulant core Ilias S. Kotsireas a,1, , Christos@wlu.ca (Ilias S. Kotsireas). 1 Supported in part by a grant from the Research Office of Wilfrid Laurier Uni

  8. 2. SECTIONAL BOILER '#4 IDEAL RED FLASH.' Hot Springs ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. SECTIONAL BOILER '#4 IDEAL RED FLASH.' - Hot Springs National Park, Bathhouse Row, Ozark Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  9. Reported Effects of Masculine Ideals on Gay Men

    Microsoft Academic Search

    Francisco J. Sánchez; Stefanie T. Greenberg; William Ming Liu; Eric Vilain

    2009-01-01

    This exploratory study used consensual qualitative research methodology to analyze what gay men associate with masculinity and femininity, how they feel masculine ideals affect their self-image, and how masculine ideals affect their same-sex relationships. Written responses were collected from 547 self-identified gay men in the United States via an Internet-based survey. Findings supported previous reports that perceptions of gender roles

  10. Ideal spiral bevel gears - A new approach to surface geometry

    NASA Technical Reports Server (NTRS)

    Huston, R. L.; Coy, J. J.

    1980-01-01

    This paper discusses the fundamental geometrical characteristics of spiral bevel gear tooth surfaces. The parametric representation of an ideal spiral bevel tooth is developed. The development is based on the elements of involute geometry, differential geometry, and fundamental gearing kinematics. A foundation is provided for the study of nonideal gears and the effects of deviations from ideal geometry on the contact stresses, lubrication, wear, fatigue life, and gearing kinematics.

  11. Ideal spiral bevel gears: A new approach to surface geometry

    NASA Technical Reports Server (NTRS)

    Huston, R. L.; Coy, J. J.

    1980-01-01

    The fundamental geometrical characteristics of spiral bevel gear tooth surfaces are discussed. The parametric representation of an ideal spiral bevel tooth is developed based on the elements of involute geometry, differential geometry, and fundamental gearing kinematics. A foundation is provided for the study of nonideal gears and the effects of deviations from ideal geometry on the contact stresses, lubrication, wear, fatigue life, and gearing kinematics.

  12. Robot task planning in a non-ideal blocks world 

    E-print Network

    Rangadass, Vasudev

    1988-01-01

    ROBOT TASK PLANNING IN A NON-IDEAL BLOCKS WORLD A Thesis by VASUDEV RANGADASS Submitted to the Graduate College Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1988 Major Subject...: Computer Science ROBOT TASK PLANNING IN A NON-IDEAL BLOCKS WORLD A Thesis by VASUDEV RANGADASS Approved as to style and content by: Amitabha Mu ee (Chairman of Committee) Glen Williams (Member) Arun Sen (Member) Glen Williams (Head...

  13. Feminist Ideals for a Healthy Female Adolescent Sexuality: A Critique

    Microsoft Academic Search

    Sharon Lamb

    2010-01-01

    This paper explores the ideals of healthy sexuality for teenage girls in the U.S. proposed by feminist theorists and researchers.\\u000a Current ideals emphasize desire, pleasure, and subjectivity, and appear to be a response to three historically problematic\\u000a areas for women and girls: objectification; abuse and victimization; and stereotypes of female passivity. There are, however,\\u000a several problems with using these qualities

  14. Design and verification of nearly ideal flow and heat transfer in a rotating disk chemical vapor deposition reactor

    Microsoft Academic Search

    William G. Breiland; G. H. Evans

    1991-01-01

    A research chemical vapor deposition reactor design is presented for a rotating disk configuration. The reactor can be operated under conditions such that nearly ideal, one-dimensional, infinite-radius disk behavior is achieved over most of the disk surface. Boundary conditions, flow stability under both isothermal and heated-disk conditions, and gas temperatures are addressed with both one- and two-dimensional numerical fluid mechanics

  15. Detonation Failure Characterization of Non-Ideal Explosives

    NASA Astrophysics Data System (ADS)

    Janesheski, Robert; Son, Steven; Groven, Lori

    2011-06-01

    Non-ideal explosives are currently poorly characterized, which limits the modeling of them. Current characterization requires large-scale testing to obtain detonation wave characterization for analysis due to the relatively thick reaction zones. Use of a microwave interferometer applied to small-scale confined experiments is being implemented to allow for time resolved characterization of a failing detonation. The microwave interferometer measures the failing detonation wave in a tube, and this experiment only requires small amounts of non-ideal explosives. A non-ideal explosive is initiated with a booster charge and a measurement of the failure distance and a continuous position-time trace of the detonation front location can be obtained. Initial tests have been performed that show this method is feasible using an ammonium perchlorate (AP) composite propellant as a model non-ideal explosive. Future work will apply this approach to non-ideal explosives. Successful results of this method would allow for the calibration of detonation models for many different non-ideal explosives. This project was funded by the Department of Homeland Security through the Center of Excellence for Explosive Detection, Mitigation, and Response under award number 080409/0002251.

  16. Topological order in the fractional quantum Hall states

    E-print Network

    Barkeshli, Maissam

    2010-01-01

    This thesis is focused on the theoretical characterization of topological order in non-Abelian fractional quantum Hall (FQH) states. The first part of the thesis is concerned with the ideal wave function approach to FQH ...

  17. This paper considers an idealized subclass of surface reflectivities; namely, a simple superposition of ideal diffuse and ideal specular, restricted to

    E-print Network

    Banks, David

    fur [Kajiya85], hair [Anjyo92, Miller88, LeBlanc91, Watanabe92], or anisotropic grooves on a surfaceABSTRACT This paper considers an idealized subclass of surface reflectivities; namely, a simple codimensions. If a surface is grooved or furry, it can be illuminated with a hybrid model that incorporates

  18. Quantum rotor in nanostructured superconductors

    PubMed Central

    Lin, Shi-Hsin; Miloševi?, M. V.; Covaci, L.; Jankó, B.; Peeters, F. M.

    2014-01-01

    Despite its apparent simplicity, the idealized model of a particle constrained to move on a circle has intriguing dynamic properties and immediate experimental relevance. While a rotor is rather easy to set up classically, the quantum regime is harder to realize and investigate. Here we demonstrate that the quantum dynamics of quasiparticles in certain classes of nanostructured superconductors can be mapped onto a quantum rotor. Furthermore, we provide a straightforward experimental procedure to convert this nanoscale superconducting rotor into a regular or inverted quantum pendulum with tunable gravitational field, inertia, and drive. We detail how these novel states can be detected via scanning tunneling spectroscopy. The proposed experiments will provide insights into quantum dynamics and quantum chaos. PMID:24686241

  19. Quantum rotor in nanostructured superconductors.

    PubMed

    Lin, Shi-Hsin; Miloševi?, M V; Covaci, L; Jankó, B; Peeters, F M

    2014-01-01

    Despite its apparent simplicity, the idealized model of a particle constrained to move on a circle has intriguing dynamic properties and immediate experimental relevance. While a rotor is rather easy to set up classically, the quantum regime is harder to realize and investigate. Here we demonstrate that the quantum dynamics of quasiparticles in certain classes of nanostructured superconductors can be mapped onto a quantum rotor. Furthermore, we provide a straightforward experimental procedure to convert this nanoscale superconducting rotor into a regular or inverted quantum pendulum with tunable gravitational field, inertia, and drive. We detail how these novel states can be detected via scanning tunneling spectroscopy. The proposed experiments will provide insights into quantum dynamics and quantum chaos. PMID:24686241

  20. Quantum rotor in nanostructured superconductors

    NASA Astrophysics Data System (ADS)

    Lin, Shi-Hsin; Miloševi?, M. V.; Covaci, L.; Jankó, B.; Peeters, F. M.

    2014-04-01

    Despite its apparent simplicity, the idealized model of a particle constrained to move on a circle has intriguing dynamic properties and immediate experimental relevance. While a rotor is rather easy to set up classically, the quantum regime is harder to realize and investigate. Here we demonstrate that the quantum dynamics of quasiparticles in certain classes of nanostructured superconductors can be mapped onto a quantum rotor. Furthermore, we provide a straightforward experimental procedure to convert this nanoscale superconducting rotor into a regular or inverted quantum pendulum with tunable gravitational field, inertia, and drive. We detail how these novel states can be detected via scanning tunneling spectroscopy. The proposed experiments will provide insights into quantum dynamics and quantum chaos.

  1. Childhood Lifestyle and Clinical Determinants of Adult Ideal

    PubMed Central

    Laitinen, Tomi T.; Pahkala, Katja; Venn, Alison; Woo, Jessica G; Oikonen, Mervi; Dwyer, Terence; Mikkilä, Vera; Hutri-Kähönen, Nina; Smith, Kylie J.; Gall, Seana L.; Morrison, John A.; Viikari, Jorma S.A.; Raitakari, Olli T.; Magnussen, Costan G.; Juonala, Markus

    2013-01-01

    Background The American Heart Association recently defined ideal cardiovascular health by simultaneous presence of seven health behaviors and factors. The concept is associated with cardiovascular disease incidence, and cardiovascular disease and all-cause mortality. To effectively promote ideal cardiovascular health already early in life, childhood factors predicting future ideal cardiovascular health should be investigated. Our aim was thus to comprehensively explore childhood determinants of adult ideal cardiovascular health in population based cohorts from three continents. Methods The sample comprised a total of 4409 participants aged 3–19 years at baseline from the Cardiovascular Risk in Young Finns Study (YFS; N=1883) from Finland, Childhood Determinants of Adult Health Study (CDAH; N=1803) from Australia and Princeton Follow-up Study (PFS; N=723) from the United States. Participants were re-examined 19–31 years later when aged 30–48 years. Results In multivariable analyses, independent childhood predictors of adult ideal cardiovascular health were family socioeconomic status (P<0.01; direct association) and BMI (P<0.001; inverse association) in all cohorts. In addition, blood pressure (P=0.007), LDL-cholesterol (P<0.001) and parental smoking (P=0.006) in the YFS, and own smoking (P=0.001) in CDAH were inversely associated with future ideal cardiovascular health. Conclusions Among several lifestyle and clinical indicators studied, higher family socioeconomic status and non-smoking (parental/own) in childhood independently predict ideal cardiovascular health in adulthood. As atherosclerotic cardiovascular diseases are rooted in childhood, our findings suggest that special attention could be paid to children who are from low socioeconomic status families, and who smoke or whose parents smoke, to prevent cardiovascular disease morbidity and mortality. PMID:24075574

  2. Quantum cascade laser investigations of CH{sub 4} and C{sub 2}H{sub 2} interconversion in hydrocarbon/H{sub 2} gas mixtures during microwave plasma enhanced chemical vapor deposition of diamond

    SciTech Connect

    Ma Jie; Cheesman, Andrew; Ashfold, Michael N. R. [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Hay, Kenneth G.; Wright, Stephen; Langford, Nigel; Duxbury, Geoffrey [Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Mankelevich, Yuri A. [Skobel'tsyn Institute of Nuclear Physics, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)

    2009-08-01

    CH{sub 4} and C{sub 2}H{sub 2} molecules (and their interconversion) in hydrocarbon/rare gas/H{sub 2} gas mixtures in a microwave reactor used for plasma enhanced diamond chemical vapor deposition (CVD) have been investigated by line-of-sight infrared absorption spectroscopy in the wavenumber range of 1276.5-1273.1 cm{sup -1} using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or Ne), input gas mixing ratio], height (z) above the substrate, and time (t) after addition of hydrocarbon to a pre-existing Ar/H{sub 2} plasma. The line integrated absorptions so obtained have been converted to species number densities by reference to the companion two-dimensional (r,z) modeling of the CVD reactor described in Mankelevich et al. [J. Appl. Phys. 104, 113304 (2008)]. The gas temperature distribution within the reactor ensures that the measured absorptions are dominated by CH{sub 4} and C{sub 2}H{sub 2} molecules in the cool periphery of the reactor. Nonetheless, the measurements prove to be of enormous value in testing, tensioning, and confirming the model predictions. Under standard process conditions, the study confirms that all hydrocarbon source gases investigated (methane, acetylene, ethane, propyne, propane, and butane) are converted into a mixture dominated by CH{sub 4} and C{sub 2}H{sub 2}. The interconversion between these two species is highly dependent on the local gas temperature and the H atom number density, and thus on position within the reactor. CH{sub 4}->C{sub 2}H{sub 2} conversion occurs most efficiently in an annular shell around the central plasma (characterized by 1400gas}<2200 K), while the reverse transformation C{sub 2}H{sub 2}->CH{sub 4} is favored in the more distant regions where T{sub gas}<1400 K. Analysis of the multistep interconversion mechanism reveals substantial net consumption of H atoms accompanying the CH{sub 4}->C{sub 2}H{sub 2} conversion, whereas the reverse C{sub 2}H{sub 2}->CH{sub 4} process only requires H atoms to drive the reactions; H atoms are not consumed by the overall conversion.

  3. Ultra LI-ideals in lattice implication algebras and MTL-algebras

    E-print Network

    Xiaohong Zhang; Keyun Qin; Wieslaw A. Dudek

    2007-10-20

    A mistake concerning the ultra \\textit{LI}-ideal of a lattice implication algebra is pointed out, and some new sufficient and necessary conditions for an \\textit{LI}-ideal to be an ultra \\textit{LI}-ideal are given. Moreover, the notion of an \\textit{LI}-ideal is extended to MTL-algebras, the notions of a (prime, ultra, obstinate, Boolean) \\textit{LI}-ideal and an \\textit{ILI}-ideal of an MTL-algebra are introduced, some important examples are given, and the following notions are proved to be equivalent in MTL-algebra: (1) prime proper \\textit{LI}-ideal and Boolean \\textit{LI}-ideal, (2) prime proper \\textit{LI}-ideal and \\textit{ILI}-ideal, (3) proper obstinate \\textit{LI}-ideal, (4) ultra \\textit{LI}-ideal.

  4. Relativistic quantum private database queries

    NASA Astrophysics Data System (ADS)

    Sun, Si-Jia; Yang, Yu-Guang; Zhang, Ming-Ou

    2015-04-01

    Recently, Jakobi et al. (Phys Rev A 83, 022301, 2011) suggested the first practical private database query protocol (J-protocol) based on the Scarani et al. (Phys Rev Lett 92, 057901, 2004) quantum key distribution protocol. Unfortunately, the J-protocol is just a cheat-sensitive private database query protocol. In this paper, we present an idealized relativistic quantum private database query protocol based on Minkowski causality and the properties of quantum information. Also, we prove that the protocol is secure in terms of the user security and the database security.

  5. Informational derivation of Quantum Theory

    E-print Network

    G. Chiribella; G. M. D'Ariano; P. Perinotti

    2011-07-15

    Quantum theory can be derived from purely informational principles. Five elementary axioms-causality, perfect distinguishability, ideal compression, local distinguishability, and pure conditioning-define a broad class of theories of information-processing that can be regarded as a standard. One postulate-purification-singles out quantum theory within this class. The main structures of quantum theory, such as the representation of mixed states as convex combinations of perfectly distinguishable pure states, are derived directly from the principles without using the Hilbert space framework.

  6. Ionization Chemistry and Role of Grains on Non-ideal MHD Effects in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Xu, Rui; Bai, Xue-Ning; Oberg, Karin I.

    2015-01-01

    Ionization in protoplanetary disks (PPDs) is one of the key elements for understanding disk chemistry. It also determines the coupling between gas and magnetic fields hence strongly affect PPD gas dynamics. We study the ionization chemistry in the presence of grains in the midplane region of PPDs and its impact on gas conductivity reflected in non-ideal MHD effects including Ohmic resistivity, Hall effect and ambipolar diffusion. We first develop a reduced chemical reaction network from the UMIST database. The reduced network contains much smaller number of species and reactions while yields reliable estimates of the disk ionization level compared with the full network. We further show that grains are likely the dominant charge carrier in the midplane regions of the inner disk, which significantly affects the gas conductivity. In particular, ambipolar diffusion is strongly reduced and the Hall coefficient changes sign in the presence of strong magnetic field. The latter provides a natural mechanism to the saturation of the Hall-shear instability.

  7. PLANETESIMAL AND PROTOPLANET DYNAMICS IN A TURBULENT PROTOPLANETARY DISK: IDEAL STRATIFIED DISKS

    SciTech Connect

    Yang, Chao-Chin [Department of Astronomy, University of Illinois, Urbana, IL 61801 (United States); Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, New York, NY 10024 (United States); Menou, Kristen, E-mail: ccyang@ucolick.org, E-mail: mordecai@amnh.org, E-mail: kristen@astro.columbia.edu [Department of Astronomy, Columbia University, New York, NY 10027 (United States)

    2012-04-01

    Due to the gravitational influence of density fluctuations driven by magneto-rotational instability in the gas disk, planetesimals and protoplanets undergo diffusive radial migration as well as changes in other orbital properties. The magnitude of the effect on particle orbits can have important consequences for planet formation scenarios. We use the local-shearing-box approximation to simulate an ideal, isothermal, magnetized gas disk with vertical density stratification and simultaneously evolve numerous massless particles moving under the gravitational field of the gas and the host star. We measure the evolution of the particle orbital properties, including mean radius, eccentricity, inclination, and velocity dispersion, and its dependence on the disk properties and the particle initial conditions. Although the results converge with resolution for fixed box dimensions, we find the response of the particles to the gravity of the turbulent gas correlates with the horizontal box size, up to 16 disk scale heights. This correlation indicates that caution should be exercised when interpreting local-shearing-box models involving gravitational physics of magneto-rotational turbulence. Based on heuristic arguments, nevertheless, the criterion L{sub h} /R {approx} O(1), where L{sub h} is the horizontal box size and R is the distance to the host star, is proposed to possibly circumvent this conundrum. If this criterion holds, we can still conclude that magneto-rotational turbulence seems likely to be ineffective at driving either diffusive migration or collisional erosion under most circumstances.

  8. Modeling of heavy-gas effects on airfoil flows

    NASA Technical Reports Server (NTRS)

    Drela, Mark

    1992-01-01

    Thermodynamic models were constructed for a calorically imperfect gas and for a non-ideal gas. These were incorporated into a quasi one dimensional flow solver to develop an understanding of the differences in flow behavior between the new models and the perfect gas model. The models were also incorporated into a two dimensional flow solver to investigate their effects on transonic airfoil flows. Specifically, the calculations simulated airfoil testing in a proposed high Reynolds number heavy gas test facility. The results indicate that the non-idealities caused significant differences in the flow field, but that matching of an appropriate non-dimensional parameter led to flows similar to those in air.

  9. Evaluation of liquid-gas separator materials for a silver zinc cell vent

    Microsoft Academic Search

    C. C. Badcock; A. H. Zimmerman

    1979-01-01

    The gas permeability of TFE Teflon, FEP Teflon, polyethylene, and microporous Teflon was measured in order to evaluate the suitability of these materials for use as liquid-gas separators for silver zinc cell vents. Microporous Teflon was found to have ideal characteristics for a liquid-gas separator. This material has a high gas permeability, it is not wetted by electrolyte, and it

  10. Similarity solutions for imploding shocks in non-ideal magnetogasdynamics

    NASA Astrophysics Data System (ADS)

    Singh, L. P.; Singh, M.; Husain, Akmal

    2011-02-01

    In the present article, similarity solutions of second kind to a problem of imploding cylindrical shock wave in non-ideal magnetogasdynamics are investigated. The equation of state of the medium is assumed to be in the form of the Mie-Gruneisen type. A numerical study of singular points of the differential equations leads to determination of the similarity exponent. Numerical description of the flow field has been presented in non-ideal magnetogasdynamics. The results obtained are compared with the numerical solution obtained by using CCW approximation method. Detailed studies are carried out for two different physically meaningful non-ideal medium in the presence of magnetic field. Also, the effect on magnetic field of flow variables such as density, velocity, pressure and magnetic pressure behind the wave front is illustrated through figures.

  11. Body ideals for heterosexual romantic partners: gender and sociocultural influences.

    PubMed

    Murnen, Sarah K; Poinsatte, Katherine; Huntsman, Karen; Goldfarb, Jesse; Glaser, Daniel

    2015-01-01

    In the present study, heterosexual college women (N=327) and men (N=160) were asked about their body type preferences for (hypothetical) romantic partners. Participants chose a particular silhouette value as ideal for a romantic partner, and rated how important it was to them for their partner to have this ideal body type. Men placed more importance on the body silhouette they chose for a partner than women did, and men's importance ratings were positively associated with the rated sexual permissiveness of their peer group and their total media use. Consuming sports media and watching reality television were the best media predictors of men's judgments about women's bodies. Less variability was explained in women's preferences for men partners' bodies, but endorsing adversarial sexual attitudes was positively related to judging the ideals chosen for men's bodies as important. Results were interpreted within both evolutionary and sociocultural theoretical frameworks. PMID:25462878

  12. An experimental test of noncontextuality without unwarranted idealizations

    E-print Network

    Michael D. Mazurek; Matthew F. Pusey; Ravi Kunjwal; Kevin J. Resch; Robert W. Spekkens

    2015-05-22

    To make precise the sense in which nature fails to respect classical physics, one requires a formal notion of classicality. Ideally, such a notion should be defined operationally, so that it can be subjected to a direct experimental test, and it should be applicable in a wide variety of experimental scenarios, so that it can cover the breadth of phenomena that are thought to defy classical understanding. Bell's notion of local causality fulfills the first criterion but not the second. The notion of noncontextuality fulfills the second criterion, but it is a long-standing question whether it can be made to fulfill the first. Previous attempts to experimentally test noncontextuality have all presumed certain idealizations that do not hold in real experiments, namely, noiseless measurements and exact operational equivalences. We here show how to devise tests that are free of these idealizations. We also perform a photonic implementation of one such test that rules out noncontextual models with high confidence.

  13. Reported Effects of Masculine Ideals on Gay Men

    PubMed Central

    Sánchez, Francisco J.; Greenberg, Stefanie T.; Liu, William Ming; Vilain, Eric

    2010-01-01

    This exploratory study used consensual qualitative research methodology (Hill et al., 2005) to analyze what gay men associate with masculinity and femininity, how they feel masculine ideals affect their self-image, and how masculine ideals affect their same-sex relationships. Written responses were collected from 547 self-identified gay men in the U.S. via an Internet-based survey. Findings supported previous reports that perceptions of gender roles among gay men appear based on masculine and feminine stereotypes. Additionally, more adverse versus positive effects on self-image and same-sex romantic relationships were reported including difficulty being emotional and affectionate, pressure to be physically attractive, and pressure to appear masculine in order to be accepted by society and to be seen as desirable by other gay men. While research on gay men’s experience with masculinity continues, psychologists should consider the possible influence of traditional masculine ideals when conceptualizing their gay male clients. PMID:20628534

  14. Optimum Anthropometric Criteria for Ideal Body Composition Related Fitness

    PubMed Central

    Kilani, Hashem; Abu-Eisheh, Asem

    2010-01-01

    Objectives The three aims of this study were to establish equations for ideal body composition related fitness to be used by adults willing to gain optimum body composition related fitness; to predict the possible symmetrical major muscle circumference, and to compute the ideal body fat percentage (BFP) with ideal body weight (IBW) based on the body mass index (BMI). Methods Twenty-four athletes were intentionally selected, with heights of 166–190 cm and aged 20–42 years, according to a judging committee that used modified International Fitness Federation criteria for the Mr. Fitness competition “super body category”. Common anthropometric and body composition measurements were taken for the following independent variables: body height, upper limb length, lower limb length, thigh length, arm length, shoulder width, forearm length, shank length, and wrist girth; and for the following dependent variables: circumferences of shoulder, thigh, waist, hip, chest, biceps, forearm, shank, and neck. Skin fold thickness was measured at three sites by a Harpenden caliper to calculate BFP. Results The findings indicate that there was a predictive correlation between major independent variables and body circumferences. The mean range used to find out the ideal BFP percentage which was 5.6–6.7 %. The BMI equation used to find the IBW was H2 × 23.77 ± 2 SE. Stepwise multiple regressions were also used to derive predictive equations. The most predictive independent variables were wrist girth and height. Conclusion It is suggested that the above equations, the ideal BFP percentage and the IBW be used as criteria in training sessions to achieve ideal body composition related fitness. PMID:21509084

  15. Health care market deviations from the ideal market.

    PubMed

    Mwachofi, Ari; Al-Assaf, Assaf F

    2011-08-01

    A common argument in the health policy debate is that market forces allocate resources efficiently in health care, and that government intervention distorts such allocation. Rarely do those making such claims state explicitly that the market they refer to is an ideal in economic theory which can only exist under very strict conditions. This paper explores the strict conditions necessary for that ideal market in the context of health care as a means of examining the claim that market forces do allocate resources efficiently in health care. PMID:22087373

  16. Non-ideal effects on the solar equation of state

    NASA Astrophysics Data System (ADS)

    Bi, S. L.; di Mauro, M. P.; Christensen-Dalsgaard, J.

    2001-01-01

    This paper presents a simple and efficient equation of state which can be used for quick and accurate computation of the thermodynamic functions of partly ionized and weakly coupled plasmas (Bi, Di Mauro and Christensen-Dalsgaard 2000). Based on the free energy minimization method, the improvement of the equation of state includes a detailed account of the physical processes of non-ideal effects consisting of electron degeneracy, Coulomb coupling and pressure ionization. The non-ideal corrections to the equation of state are calculated under solar interior conditions. The result reveals that the contribution is quite significant, and hence modifies the thermodynamic properties of the plasma substantially.

  17. Castelnuovo regularity and graded rings associated to an ideal

    E-print Network

    Johnston, Bernard; Katz, Daniel L.

    1995-03-01

    reads as follows: Theorem (Goto-Huckaba). Let (R, m) be a Cohen-Macaulay local ring with in- finite residue field and I ç R an ideal having positive height which is generically a complete intersection and has analytic deviation one. Let s = s(I). Then 3t...-Shimoda theorem and the Trung-Ikeda theorem, but indeed there is. This connection is provided by the following result [T, Proposition 3.2]. Proposition (Trung). Let (R, m) be a local ring with infinite residue field and I ç R an ideal. For any minimal reduction J...

  18. Emergence of quantum chaos in the quantum computer core and how to manage it

    PubMed

    Georgeot; Shepelyansky

    2000-11-01

    We study the standard generic quantum computer model, which describes a realistic isolated quantum computer with fluctuations in individual qubit energies and residual short-range interqubit couplings. It is shown that in the limit where the fluctuations and couplings are small compared to the one-qubit energy spacing, the spectrum has a band structure, and a renormalized Hamiltonian is obtained which describes the eigenstate properties inside one band. Studies are concentrated on the central band of the computer ("core") with the highest density of states. We show that above a critical interqubit coupling strength, quantum chaos sets in, leading to a quantum ergodicity of the computer eigenstates. In this regime the ideal qubit structure disappears, the eigenstates become complex, and the operability of the computer is quickly destroyed. We confirm that the quantum chaos border decreases only linearly with the number of qubits n, although the spacing between multiqubit states drops exponentially with n. The investigation of time evolution in the quantum computer shows that in the quantum chaos regime, an ideal (noninteracting) state quickly disappears, and exponentially many states become mixed after a short chaotic time scale for which the dependence on system parameters is determined. Below the quantum chaos border an ideal state can survive for long times, and an be used for computation. The results show that a broad parameter region does exist where the efficient operation of a quantum computer is possible. PMID:11101971

  19. Nanosensors: towards morphological control of gas sensing activity. SnO2, In2O3, ZnO and WO3 case studies

    NASA Astrophysics Data System (ADS)

    Gurlo, Aleksander

    2011-01-01

    Anisotropy is a basic property of single crystals. Dissimilar facets/surfaces have different geometric and electronic structure that results in dissimilar functional properties. Several case studies unambiguously demonstrated that the gas sensing activity of metal oxides is determined by the nature of surfaces exposed to ambient gas. Accordingly, a control over crystal morphology, i.e. over the angular relationships, size and shape of faces in a crystal, is required for the development of better sensors with increased selectivity and sensitivity in the chemical determination of gases. The first step toward this nanomorphological control of the gas sensing properties is the design and synthesis of well-defined nanocrystals which are uniform in size, shape and surface structure. These materials possess the planes of the symmetrical set {hkl} and must therefore behave identically in chemical reactions and adsorption processes. Because of these characteristics, the form-controlled nanocrystals are ideal candidates for fundamental studies of mechanisms of gas sensing which should involve (i) gas sensing measurements on specific surfaces, (ii) their atomistic/quantum chemical modelling and (ii) spectroscopic information obtained on same surfaces under operation conditions of sensors.Anisotropy is a basic property of single crystals. Dissimilar facets/surfaces have different geometric and electronic structure that results in dissimilar functional properties. Several case studies unambiguously demonstrated that the gas sensing activity of metal oxides is determined by the nature of surfaces exposed to ambient gas. Accordingly, a control over crystal morphology, i.e. over the angular relationships, size and shape of faces in a crystal, is required for the development of better sensors with increased selectivity and sensitivity in the chemical determination of gases. The first step toward this nanomorphological control of the gas sensing properties is the design and synthesis of well-defined nanocrystals which are uniform in size, shape and surface structure. These materials possess the planes of the symmetrical set {hkl} and must therefore behave identically in chemical reactions and adsorption processes. Because of these characteristics, the form-controlled nanocrystals are ideal candidates for fundamental studies of mechanisms of gas sensing which should involve (i) gas sensing measurements on specific surfaces, (ii) their atomistic/quantum chemical modelling and (ii) spectroscopic information obtained on same surfaces under operation conditions of sensors. Current address: Harvard School of Applied and Engineering Sciences (SEAS), Harvard University, 29 Oxford Street, Cambridge, MA 02138, USA; Phone: 001-617-496-4295; e-mail: agurlo@seas.harvard.edu

  20. Social Comparison and the Idealized Images of Advertising

    Microsoft Academic Search

    Marsha L. Richins

    1991-01-01

    This article reviews theories that might explain how advertising causes dissatisfaction with the self. It is hypothesized that consumers compare themselves with idealized advertising images. Exposure to such images may change consumers comparison standards for what they desire or lower perceptions of their own performance on relevant dimensions; the result is lowered satisfaction. Explanatory and experimental research examined these hypotheses

  1. Theoretical Analysis of an Ideal Startup Scheme in Multihomed SCTP

    E-print Network

    Boyer, Edmond

    Theoretical Analysis of an Ideal Startup Scheme in Multihomed SCTP Johan Eklund1 , Karl the available bandwidth on the alternate path it is possible to utilize a more efficient startup scheme startup scenario. We identify three different scenarios, where a path swap could occur. Further, we

  2. Exploring the Ideal of Teaching as Consummatory Experience

    ERIC Educational Resources Information Center

    Oral, Sevket Benhur

    2013-01-01

    In this article, it is argued that fulfilling teaching and educative experiences go hand in hand. Not only is it possible to be fully alive as a teacher, it is also essential for educative experience to unfold in students. To substantiate the claim made here, an analysis of what I would like to call the ideal of teaching as consummatory experience…

  3. Linearizing the inverse quadratic almost ideal demand system

    Microsoft Academic Search

    Toshinobu Matsuda

    2007-01-01

    This article investigates the linear approximation to the inverse quadratic almost ideal demand system (IQUAIDS), a recently introduced flexible functional form with potential usefulness. Linearizing this nonlinear model is of practical importance because nonstationary data, which are likely to be used in inverse demand systems, can be handled more properly in linear models. The IQUAIDS is linearized by replacing the

  4. Linear approximations to the quadratic almost ideal demand system

    Microsoft Academic Search

    Toshinobu Matsuda

    2006-01-01

    This paper investigates linear approximations to the recently popular quadratic almost ideal demand system (QUAIDS) by proposing a new composite variable and conducting a simulation study. The linear approximations are especially useful when one uses nonstationary time series, to which nonlinear systems are difficult to apply properly. The new composite variable performs well in combination with the price indices appropriate

  5. Be Very Afraid: Cyborg Athlete, Transhuman Ideals & Posthumanity

    Microsoft Academic Search

    Andy Miah

    2004-01-01

    This paper argues that transhumanism lacks persuasiveness because its futurological underpinnings are met with skepticism, not due to a lack of applicability, but for the lack of clarity about how transhumanity can become manifest within a cautious technological society. It is considered that the integration of transhuman ideals within social praxis is problematic in a variety of social contexts, but

  6. Standard Bases of Differential Ideals (1) Francois Ollivier

    E-print Network

    Ollivier, François

    ­ dard bases of D­modules introduced by Castro [Cas]. We will deal with commutative differential rings, not rings of differential operators. Effective---or almost effective---methods for solving systems1 Standard Bases of Differential Ideals (1) Fran¸cois Ollivier Laboratoire d'Informatique de l'X (L

  7. On the prime ideal structure of symbolic Rees algebras

    Microsoft Academic Search

    S. Bouchiba; S. Kabbaj

    2009-01-01

    This paper contributes to the study of the prime spectrum and dimension theory of symbolic Rees algebra over Noetherian domains. We first establish some general results on the prime ideal structure of subalgebras of affine domains, which actually arise, in the Noetherian context, as domains between a domain $A$ and $A[a^{-1}]$. We then examine closely the special context of symbolic

  8. Secretarial Personality: The Ideal According to Holland and Bem Profiles.

    ERIC Educational Resources Information Center

    Brink, T. L.

    Personnel directors (N=34) responded to a mailed adjective checklist describing the ideal secretary. This list contained eight adjectives cxorresponding to each of Holland's six vocationally-related personality traits (Realistic, Social, Investigative, Enterprising, Conventional, and Artistic) and eight feminine and eight masculine adjectives from…

  9. Trees, parking functions, syzygies, and deformations of monomial ideals

    Microsoft Academic Search

    Alexander Postnikov; Boris Shapiro

    2003-01-01

    For a graph G, we construct two algebras, whose dimensions are both equal to the number of spanning trees of G. One of these algebras is the quotient of the polynomial ring modulo certain monomial ideal, while the other is the quotient of the polynomial ring modulo certain powers of linear forms. We describe the set of monomials that forms

  10. Education as Immortality: Toward the Rehabilitation of an Ideal.

    ERIC Educational Resources Information Center

    Blacker, David

    1998-01-01

    Observes that immortality remains an important animating ideal for teaching and learning, despite being long neglected as theological or egoistic. Makes the case that the role of immortality in pedagogy has a long history in Western thought. Argues that individuals should recognize and address ways that longing for immortality shapes educators'…

  11. Symbols of Democracy: An Introduction to Icons and Ideals

    ERIC Educational Resources Information Center

    Kofsky, Jackie; Morris, Barb

    2006-01-01

    Many young students are unfamiliar with key symbols of the United States and the ideals that these symbols represent. These symbols consist of images and words that adults know by heart, but too often take for granted. The lesson activities described in this article focus on four well-known symbols--their history and what they mean to American…

  12. Analysis of Contingency Tables by Ideal Point Discriminant Analysis.

    ERIC Educational Resources Information Center

    Takane, Yoshio

    1987-01-01

    Ideal point discriminant analysis (IPDA) is proposed for the analysis of contingency tables of cross-classified data. Several data sets illustrate IPDA, which combines log-linear and dual scaling models to provide a spatial representation of row and column categories and allow statistical evaluation of various structural hypotheses about…

  13. The ideal physician: implications for contemporary hospital marketing.

    PubMed

    Gochman, D S; Stukenborg, G J; Feler, A

    1986-06-01

    A questionnaire asking individuals to identify freely the characteristics most descriptive of physicians who are closest to their ideal was mailed to a systematically derived cluster sample in a medium-size metropolitan area. Respondents clearly valued psychosocial and interpersonal characteristics such as communicating and caring much more than technical medical skills. PMID:10277633

  14. Surface wave propagation in non-ideal plasmas

    NASA Astrophysics Data System (ADS)

    Pandey, B. P.; Dwivedi, C. B.

    2015-03-01

    The properties of surface waves in a partially ionized, compressible magnetized plasma slab are investigated in this work. The waves are affected by the non-ideal magnetohydrodynamic (MHD) effects which causes finite drift of the magnetic field in the medium. When the magnetic field drift is ignored, the characteristics of the wave propagation in a partially ionized plasma fluid is similar to the fully ionized ideal MHD except now the propagation properties depend on the fractional ionization as well as on the compressibility of the medium. The phase velocity of the sausage and kink waves increases marginally (by a few per cent) due to the compressibility of the medium in both ideal as well as Hall-diffusion-dominated regimes. However, unlike ideal regime, only waves below certain cut-off frequency can propagate in the medium in Hall dominated regime. This cut-off for a thin slab has a weak dependence on the plasma beta whereas for thick slab no such dependence exists. More importantly, since the cut-off is introduced by the Hall diffusion, the fractional ionization of the medium is more important than the plasma compressibility in determining such a cut-off. Therefore, for both compressible as well incompressible medium, the surface modes of shorter wavelength are permitted with increasing ionization in the medium. We discuss the relevance of these results in the context of solar photosphere-chromosphere.

  15. Kinetic Theory Derivation of the Adiabatic Law for Ideal Gases.

    ERIC Educational Resources Information Center

    Sobel, Michael I.

    1980-01-01

    Discusses how the adiabatic law for ideal gases can be derived from the assumption of a Maxwell-Boltzmann (or any other) distribution of velocities--in contrast to the usual derivations from thermodynamics alone, and the higher-order effect that leads to one-body viscosity. An elementary derivation of the adiabatic law is given. (Author/DS)

  16. Characterizing Ideal Weighted Threshold Secret Sharing Amos Beimel

    E-print Network

    Beimel, Amos

    . As a motivation, consider sharing a secret among the shareholders of some company, each holding a different amount is ideal in the sense Dept. of Computer Science, Ben-Gurion University, Beer-Sheva 84105, Israel. E. of Computer Science, Ben-Gurion University, Beer-Sheva 84105, Israel. Dept. of Comput

  17. Perception on Ideal Qualities of a Communication Student

    ERIC Educational Resources Information Center

    Pelayo, Jose Maria G., III; Mallari, Shaedy Dee C.; Manio, Joana C.; Pelayo, Jose Juancho S.

    2015-01-01

    This research study focused on the opinions and contemporary perceptions of Bachelor of Arts in Communication students in Systems Plus College Foundation. The researchers determined the acuity of the students perse on ideal qualities that the respondents should possess or acquire. It addressed with the opinions, insights and also thoughts about…

  18. Ideal Magnetohydrodynamic Spectra of Static and Flowing Plasmas

    E-print Network

    Tatsuno, Tomoya

    Ideal Magnetohydrodynamic Spectra of Static and Flowing Plasmas Tomoya Tatsuno November, 2001 #12 to be an incomplete approach. i #12;#12;Contents Abstract i 1 Introduction 1 2 Single fluid magnetohydrodynamics 5 2.1 Magnetohydrodynamic equations . . . . . . . . . . . . . . . . . . . . 5 2.2 Galilei invariance of Maxwell equations

  19. In Search for an Ideal Computer-Assisted Drawing System

    E-print Network

    Igarashi, Takeo

    In Search for an Ideal Computer-Assisted Drawing System yTakeo Igarashi, zSachiko Kawachiya, y@mtl.t.u-tokyo.ac.jp, fsachiko, matsug@is.s.u-tokyo.ac.jp ABSTRACT Diagram drawing with conventional computer-assisted drawing lead to fundamental improvement in overall drawing eciency. We have conducted an experiment to verify

  20. Correlates of Ideal Body Size among Black and White Adolescents

    ERIC Educational Resources Information Center

    Nollen, Nicole; Kaur, Harsohena; Pulvers, Kim; Choi, Won; Fitzgibbon, Marian; Li, Chaoyang; Nazir, Niaman; Ahluwalia, Jasjit S.

    2006-01-01

    Cultural differences have been found in body image perceptions among Black and White adolescents, however little is known about the factors associated with perceptions of an ideal body size (IBS). This study examined differences in correlates of IBS among 265 Black (116 girls and 62 boys) and White (63 girls and 24 boys) adolescents. IBS for White…

  1. Idealizing Ion Channel Recordings by a Jump Segmentation Multiresolution Filter

    E-print Network

    Munk, Axel

    1 Idealizing Ion Channel Recordings by a Jump Segmentation Multiresolution Filter Thomas Hotz, Ole Abstract Based on a combination of jump segmentation and statistical multiresolution analysis for dependent multiresolution criterion; subconductance. T. Hotz is with the Institute of Mathematics, Ilmenau University

  2. Amsterdam: planning and policy for the ideal city?

    Microsoft Academic Search

    John I. Gilderbloom; Matthew J. Hanka; Carrie Beth Lasley

    2009-01-01

    Is Amsterdam the “ideal city?” Many of the social, economic, and environmental problems facing Amsterdam are considerably less than those in cities in the USA, and in most cases, Western Europe. Amsterdam, at this moment in history, might be the world's greatest city because of its ability to ensure basic necessities, freedom, and creativity. Tolerance of drugs, sexual freedom, along

  3. Intrinsic geometry of convex ideal polyhedra in hyperbolic 3-space

    E-print Network

    Igor Rivin

    2000-05-23

    The main result is that every complete finite area hyperbolic metric on a sphere with punctures can be uniquely realized as the induced metric on the surface of a convex ideal polyhedron in hyperbolic 3-space. A number of other observations are included.

  4. A new shock-capturing numerical scheme for ideal hydrodynamics

    E-print Network

    Feckova, Zuzana

    2015-01-01

    We present a new algorithm for solving ideal relativistic hydrodynamics based on Godunov method with an exact solution of Riemann problem for an arbitrary equation of state. Standard numerical tests are executed, such as the sound wave propagation and the shock tube problem. Low numerical viscosity and high precision are attained with proper discretization.

  5. A new shock-capturing numerical scheme for ideal hydrodynamics

    E-print Network

    Zuzana Feckova; Boris Tomasik

    2015-01-07

    We present a new algorithm for solving ideal relativistic hydrodynamics based on Godunov method with an exact solution of Riemann problem for an arbitrary equation of state. Standard numerical tests are executed, such as the sound wave propagation and the shock tube problem. Low numerical viscosity and high precision are attained with proper discretization.

  6. A new shock-capturing numerical scheme for ideal hydrodynamics

    NASA Astrophysics Data System (ADS)

    Fecková, Z.; Tomášik, B.

    2015-05-01

    We present a new algorithm for solving ideal relativistic hydrodynamics based on Godunov method with an exact solution of Riemann problem for an arbitrary equation of state. Standard numerical tests are executed, such as the sound wave propagation and the shock tube problem. Low numerical viscosity and high precision are attained with proper discretization.

  7. The Ideal of a Catholic Education in a Secularized Society

    ERIC Educational Resources Information Center

    Cuypers, Stefaan E.

    2004-01-01

    This paper argues that the progressive, revisionist reaction within Catholic education and schooling, as well as within Catholicism at large, to the challenge of modernity is a mistake. In view of modernity's malaises, it advocates instead the affirmation or reaffirmation of the ideal of traditional Catholicism as the only authentic response for…

  8. Anharmonic Vibrations of an "Ideal" Hooke's Law Oscillator

    ERIC Educational Resources Information Center

    Thomchick, John; McKelvey, J. P.

    1978-01-01

    Presents a model describing the vibrations of a mass connected to fixed supports by "ideal" Hooke's law springs which may serve as a starting point in the study of the properties of irons in a crystal undergoing soft mode activated transition. (SL)

  9. Ventilation of the Miocene Arctic Ocean: An idealized model study

    Microsoft Academic Search

    Bijoy Thompson; Johan Nilsson; Jonas Nycander; Martin Jakobsson; Kristofer Döös

    2010-01-01

    A model study of an idealized early Miocene Arctic Ocean has been undertaken. The work is motivated by the first drill core retrieved from the Lomonosov Ridge in the central Arctic Ocean, which suggests a transition from anoxic to oxic condition during the early Miocene, a feature presumably related to the opening of the Fram Strait. Here, the ventilation in

  10. An Ideal Observer Analysis of Visual Working Memory

    ERIC Educational Resources Information Center

    Sims, Chris R.; Jacobs, Robert A.; Knill, David C.

    2012-01-01

    Limits in visual working memory (VWM) strongly constrain human performance across many tasks. However, the nature of these limits is not well understood. In this article we develop an ideal observer analysis of human VWM by deriving the expected behavior of an optimally performing but limited-capacity memory system. This analysis is framed around…

  11. Ideal Knowing: Logics of Knowledge in Primary School Curricula

    ERIC Educational Resources Information Center

    Macknight, Vicki

    2011-01-01

    This paper is written to draw attention to the ideal knower and the logic of knowledge embedded in curricula. New logics and new knowers, I argue, are conjured with the hope they will be capable of succeeding in curriculum designers' imagined future. I frame this discussion in terms of debates about the place of knowledge in the sociology of…

  12. On the Complexity of the Montes Ideal Factorization Algorithm

    E-print Network

    Ford, David

    On the Complexity of the Montes Ideal Factorization Algorithm David Ford and Olga Veres Concordia@cse.concordia.ca, overes@mathstat.concordia.ca Abstract. Let p be a rational prime and let (X) be a monic irreducible of the Montes algorithm, merely testing (X) for irreducibility over Qp, is given in [19], together with a full

  13. Mad about Ideals? Educating Children to Become Reasonably Passionate

    ERIC Educational Resources Information Center

    Sieckelinck, Stijn M. A.; de Ruyter, Doret J.

    2009-01-01

    The current public concern about radicalization and extremism challenges philosophers and particularly philosophers of education to explore questions such as "Why do adolescents with strong ideas transgress?" and "What can we do about it?" The first question can be addressed by examining the role of their passionate commitment to their ideals as…

  14. Globalisation, Globalism and Cosmopolitanism as an Educational Ideal

    ERIC Educational Resources Information Center

    Papastephanou, Marianna

    2005-01-01

    In this paper, I discuss globalisation as an empirical reality that is in a complex relation to its corresponding discourse and in a critical distance from the cosmopolitan ideal. I argue that failure to grasp the distinctions between globalisation, globalism, and cosmopolitanism derives from mistaken identifications of the Is with the Ought and…

  15. Radical Ideals and their Varieties The Strong Nullstellensatz

    E-print Network

    Kalla, Priyank

    Radical Ideals and their Varieties The Strong Nullstellensatz Priyank Kalla Associate Professor. Kalla (Univ. of Utah) Radicals and I(V (J)) Nov 10-12, 2014 2 / 22 #12;Before we get to Strong (Univ. of Utah) Radicals and I(V (J)) Nov 10-12, 2014 3 / 22 #12;Before we get to Strong Nullstellensatz

  16. Cork agglomerates as an ideal core material in lightweight structures

    Microsoft Academic Search

    Osvaldo Castro; José M. Silva; Tessaleno Devezas; Arlindo Silva; Luís Gil

    2010-01-01

    The experiments carried out in this investigation were oriented in order to optimize the properties of cork-based agglomerates as an ideal core material for sandwich components of lightweight structures, such as those used in aerospace applications. Static bending tests were performed in order to characterize the mechanical strength of different types of cork agglomerates which were obtained considering distinct production

  17. Current dipole localization with an ideal magnetometer system

    Microsoft Academic Search

    Bernd Lutkenhoner

    1996-01-01

    The goal of the study was to explore the most fundamental aspects of a magnetoencephalography (MEG)-based dipole source analysis. For that purpose, a MEG measurement with an ideal magnetometer system (providing the radial component of the magnetic field as a continuous function) is considered. The analytical formulas derived for the variances and covariances of the parameter estimation errors, validated by

  18. Idealized Hot Spot Experiments with a General Circulation Model

    E-print Network

    Maloney, Eric

    Idealized Hot Spot Experiments with a General Circulation Model Eric D. Maloney* College of Oceanic to an initial localized positive equatorial SST anomaly, or "hot spot". A hot spot is imposed upon an aquaplanet develops near the hot spot, forcing an anomalous large-scale circulation that resembles the linear response

  19. University educational reform in the sixties — Ideals, goals, and results

    Microsoft Academic Search

    Christian Bay

    1988-01-01

    This paper discusses in historical context the most basic ideals and goals of the student rebels of the 1960s. Primary attention is paid to developments in the United States since the most important impetus for the Canadian student activists came from south of the border, where the crucial issues were racism in the southern states and the American war in

  20. Resistive Magnetohydrodynamics Simulations of the Ideal Tearing Mode

    NASA Astrophysics Data System (ADS)

    Landi, S.; Del Zanna, L.; Papini, E.; Pucci, F.; Velli, M.

    2015-06-01

    We study the linear and nonlinear evolution of the tearing instability on thin current sheets by means of two-dimensional numerical simulations, within the framework of compressible, resistive MHD. In particular we analyze the behavior of current sheets whose inverse aspect ratio scales with the Lundquist number S as {{S}-1/3}. This scaling has been recently recognized to yield the threshold separating fast, ideal reconnection, with an evolution and growth that are independent of S provided this is high enough, as it should be natural having the ideal case as a limit for S\\to ? . Our simulations confirm that the tearing instability growth rate can be as fast as ? ? 0.6 {{? }A}-1, where {{? }A} is the ideal Alfvénic time set by the macroscopic scales, for our least diffusive case with S={{10}7}. The expected instability dispersion relation and eigenmodes are also retrieved in the linear regime, for the values of S explored here. Moreover, in the nonlinear stage of the simulations we observe secondary events obeying the same critical scaling with S, here calculated on the local, much smaller lengths, leading to increasingly faster reconnection. These findings strongly support the idea that in a fully dynamic regime, as soon as current sheets develop, thin, and reach this critical threshold in their aspect ratio, the tearing mode is able to trigger plasmoid formation and reconnection on the local (ideal) Alfvénic timescales, as required to explain the explosive flaring activity often observed in solar and astrophysical plasmas.