Dissipation and decoherence by ideal quantum gas
Janos Polonyi
2015-10-12
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.
Relaxation dynamics of a quantum Brownian particle in an ideal gas
Bassano Vacchini; Klaus Hornberger
2007-06-29
We show how the quantum analog of the Fokker-Planck equation for describing Brownian motion can be obtained as the diffusive limit of the quantum linear Boltzmann equation. The latter describes the quantum dynamics of a tracer particle in a dilute, ideal gas by means of a translation-covariant master equation. We discuss the type of approximations required to obtain the generalized form of the Caldeira-Leggett master equation, along with their physical justification. Microscopic expressions for the diffusion and relaxation coefficients are obtained by analyzing the limiting form of the equation in both the Schroedinger and the Heisenberg picture.
Arik, Metin; Kholmetskii, Alexander L
2009-01-01
Previously, we established a connection between the macroscopic classical laws of gases and the quantum mechanical description of molecules of an ideal gas (T. Yarman et al. arXiv:0805.4494). In such a gas, the motion of each molecule can be considered independently on all other molecules, and thus the macroscopic parameters of the ideal gas, like pressure P and temperature T, can be introduced as a result of simple averaging over all individual motions of the molecules. It was shown that for an ideal gas enclosed in a macroscopic cubic box of volume V, the constant, arising along with the classical law of adiabatic expansion, i.e. PV5/3=constant, can be explicitly derived based on quantum mechanics, so that the constant comes to be proportional to h^2/m; here h is the Planck Constant, and m is the relativistic mass of the molecule the gas is made of. In this article we show that the same holds for a photon gas, although the related setup is quite different than the previous ideal gas setup. At any rate, we c...
Feng Wu; Lingen Chen; Fengrui Sun; Chih Wu; Fangzhong Guo; Qing Li
2006-01-01
The model of an irreversible Otto cycle using an ideal Fermi gas as the working fluid, which is called as the irreversible\\u000a Fermi Otto cycle, is established in this paper. Based on the equation of state of an ideal Fermi gas, the ecological optimization\\u000a performance of an irreversible Fermi Otto cycle is examined by taking an ecological optimization criterion as
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
Arnaud, Jacques; Philippe, Fabrice
2011-01-01
When a cylinder terminated by a piston, containing $N$ corpuscles, and with height $h$ is raised at temperature $\\theta$, the force that the corpuscles exerts on the piston is, to within constant factors: $F=N\\,\\theta/h$. This law, called the "ideal gas law", is valid at any temperature (except at very low temperatures when quantum effects are significant) and for any collection of corpuscles, in a space of arbitrary dimensions. It is usually derived under the assumption that the temperature is proportional to the corpuscle's kinetic energy. We show that this law rests only upon the democritian concept of corpuscles moving in vacuum, postulating that it is independent of the law of motion. This view-point puts aside restrictive assumptions that are sources of confusion. The present paper should accordingly facilitate the understanding of the physical meaning of the ideal gas law. The mathematics is elementary.
2/2015 ideal gas 1/8 IDEAL AND NON-IDEAL GASES
Gustafsson, Torgny
, thermometer, hot plate, stand. INTRODUCTION: The Ideal Gas The ideal gas law states that PV = nRT where be read directly from the equation. A Non-Ideal Gas We noted above that the ideal gas law holds for low-density gases. In theoretically deriving the ideal gas law it is necessary to make two assumptions -- the gas
Ideal quantum gas in expanding cavity: nature of non-adiabatic force
K. Nakamura; S. K. Avazbaev; Z. A. Sobirov; D. U. Matrasulov; T. Monnai
2011-05-21
We consider a quantum gas of non-interacting particles confined in the expanding cavity, and investigate the nature of the non-adiabatic force which is generated from the gas and acts on the cavity wall. Firstly, with use of the time-dependent canonical transformation which transforms the expanding cavity to the non-expanding one, we can define the force operator. Secondly, applying the perturbative theory which works when the cavity wall begins to move at time origin, we find that the non-adiabatic force is quadratic in the wall velocity and thereby does not break the time-reversal symmetry, in contrast with the general belief. Finally, using an assembly of the transitionless quantum states, we obtain the nonadiabatic force exactly. The exact result justifies the validity of both the definition of force operator and the issue of the perturbative theory. The mysterious mechanism of nonadiabatic transition with use of transitionless quantum states is also explained. The study is done on both cases of the hard-wall and soft-wall confinement with the time-dependent confining length.
Thermodynamics of ideal quantum gas with fractional statistics in D dimensions.
Potter, Geoffrey G; Müller, Gerhard; Karbach, Michael
2007-06-01
We present exact and explicit results for the thermodynamic properties (isochores, isotherms, isobars, response functions, velocity of sound) of a quantum gas in dimensions D > or = 1 and with fractional exclusion statistics 0 < or = g < or =1 connecting bosons (g=0) and fermions (g=1) . In D=1 the results are equivalent to those of the Calogero-Sutherland model. Emphasis is given to the crossover between bosonlike and fermionlike features, caused by aspects of the statistical interaction that mimic long-range attraction and short-range repulsion. A phase transition along the isobar occurs at a nonzero temperature in all dimensions. The T dependence of the velocity of sound is in simple relation to isochores and isobars. The effects of soft container walls are accounted for rigorously for the case of a pure power-law potential. PMID:17677233
Ideal Gas Law and the Gas Constant
NSDL National Science Digital Library
David N. Blauch
This site offers an interactive tutorial in which students test the validity of the ideal gas law by measuring the pressure of a gas at various molar concentrations. The value of the gas constant is determined graphically. This tutorial is coupled to others to further guide the student to a better understanding of the principles which govern the behavior of gases.
NASA Astrophysics Data System (ADS)
Wang, Jianhui; Ma, Yongli; He, Jizhou
2015-07-01
Based on quantum thermodynamic processes, we make a quantum-mechanical (QM) extension of the typical heat engine cycles, such as the Carnot, Brayton, Otto, Diesel cycles, etc., with no introduction of the concept of temperature. When these QM engine cycles are implemented by an ideal gas confined in an arbitrary power-law trap, a relation between the quantum adiabatic exponent and trap exponent is found. The differences and similarities between the efficiency of a given QM engine cycle and its classical counterpart are revealed and discussed.
Yu. E. Kuzovlev
2013-11-13
Statistics of classical Hamiltonian random walk of particle colliding with atoms of ideal gas is considered from viewpoint of earlier suggested exact pseudo-quantum path integral representation of the problem, and qualitative agreement is demostrated between results of an naturally arising simple approximation of this integral and results obtained by formally different methods, thus in a new fashion showing inevitability of scaleless 1/f-type fluctuations in rates of molecular Brownian motions and other dynamical transport and evolution processes.
ERIC Educational Resources Information Center
Sevilla, F. J.; Olivares-Quiroz, L.
2012-01-01
In this work, we address the concept of the chemical potential [mu] in classical and quantum gases towards the calculation of the equation of state [mu] = [mu](n, T) where n is the particle density and "T" the absolute temperature using the methods of equilibrium statistical mechanics. Two cases seldom discussed in elementary textbooks are…
NSDL National Science Digital Library
2011-01-01
ChemTeacher compiles background information, videos, articles, demonstrations, worksheets and activities for high school teachers to use in their classrooms. The Ideal Gas Law page includes resources for teaching students about the definition and applications of the Ideal Gas Law.
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.
Ideal quantum clocks and operator time
Walter Gessner
2013-05-04
In the framework of any quantum theory in the Schroedinger picture a general operator time concept is given. For this purpose certain systems are emphasized as ideal quantum clocks. Their definition follows heuristically from a common property of ideal clocks and from general postulates of traditional quantum theory. Any such ideal quantum clock allows the definition of a symmetric time operator T. T and the Hamiltonian H necessarily satisfy the time-energy uncertainty relation. The argument of Pauli against the existence of any time operator does not strike, because T is symmetric but not selfadjoint.
Ideal Quantum Gases in Ddimensional Space and PowerLaw Potentials
Ideal Quantum Gases in Ddimensional Space and PowerLaw Potentials Luca Salasnich Istituto Ideal Fermi and Bose Gases Let us consider a confined quantum gas of noninteracting identical Fermions Celoria 16, 20133 Milano, Italy email: salasnich@mi.infm.it Abstract We investigate ideal quantum gases
Ideal Gas Laws: Experiments for General Chemistry
ERIC Educational Resources Information Center
Deal, Walter J.
1975-01-01
Describes a series of experiments designed to verify the various relationships implicit in the ideal gas equation and shows that the success of the Graham's law effusion experiments can be explained by elementary hydrodynamics. (GS)
Ideal Gas Carnot Engines and Efficiency Chemistry 223
Ronis, David M.
Ideal Gas Carnot Engines and Efficiency Chemistry 223 Fig. 1. The Carnot Cycle The Carnot engine parts of the Carnot cycle for an ideal gas. 1. Energy in an Ideal Gas: Joule's Experiment In his study depicted below: Fall Term, 2014 #12;Ideal Gas Carnot Engines and Efficiency -2- Chemistry 223 P=0
Ideal gas matching for thermal Galilean holography
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.
Thermodynamics of an ideal generalized gas: I. Thermodynamic laws.
Lavenda, B H
2005-11-01
The equations of state for an ideal relativistic, or generalized, gas, like an ideal quantum gas, are expressed in terms of power laws of the temperature. In contrast to an ideal classical gas, the internal energy is a function of volume at constant temperature, implying that the ideal generalized gas will show either attractive or repulsive interactions. This is a necessary condition in order that the third law be obeyed and for matter to have an electromagnetic origin. The transition from an ideal generalized to a classical gas occurs when the two independent solutions of the subsidiary equation to Lagrange's equation coalesce. The equation of state relating the pressure to the internal energy encompasses the full range of cosmological scenarios, from the radiation to the matter dominated universes and finally to the vacuum energy, enabling the coefficient of proportionality, analogous to the Grüeisen ratio, to be interpreted in terms of the degrees of freedom related to the temperature exponents of the internal energy and the absolute temperature expressed in terms of a power of the empirical temperature. The limit where these exponents merge is shown to be the ideal classical gas limit. A corollary to Carnot's theorem is proved, asserting that the ratio of the work done over a cycle to the heat absorbed to increase the temperature at constant volume is the same for all bodies at the same volume. As power means, the energy and entropy are incomparable, and a new adiabatic potential is introduced by showing that the volume raised to a characteristic exponent is also the integrating factor for the quantity of heat so that the second law can be based on the property that power means are monotonically increasing functions of their order. The vanishing of the chemical potential in extensive systems implies that energy cannot be transported without matter and is equivalent to the condition that Clapeyron's equation be satisfied. PMID:16231132
Quantum cryptography with an ideal local relay
Gaetana Spedalieri; Carlo Ottaviani; Samuel L. Braunstein; Tobias Gehring; Christian S. Jacobsen; Ulrik L. Andersen; Stefano Pirandola
2015-09-03
We consider two remote parties connected to a relay by two quantum channels. To generate a secret key, they transmit coherent states to the relay, where the states are subject to a continuous-variable (CV) Bell detection. We study the ideal case where Alice's channel is lossless, i.e., the relay is locally situated in her lab and the Bell detection is performed with unit efficiency. This configuration allows us to explore the optimal performances achievable by CV measurement-device-independent (MDI) quantum key distribution (QKD). This corresponds to the limit of a trusted local relay, where the detection loss can be re-scaled. Our theoretical analysis is confirmed by an experimental simulation where 10^-4 secret bits per use can potentially be distributed at 170km assuming ideal reconciliation.
Thermodynamics of Ideal Gas in Cosmology
Ying-Qiu Gu
2009-10-04
The equation of state and the state functions for the gravitational source are necessary conditions for solving cosmological model and stellar structure. The usual treatments are directly based on the laws of thermodynamics, and the physical meanings of some concepts are obscure. This letter show that, we can actually derive all explicit fundamental state functions for the ideal gas in the context of cosmology via rigorous dynamical and statistical calculation. These relations have clear physical meanings, and are valid in both non-relativistic and ultra-relativistic cases. Some features of the equation of state are important for a stable structure of a star with huge mass.
Generalized Ideal Gas Equations for Structureful Universe
Shahid N. Afridi; Khalid Khan
2006-09-04
We have derived generalized ideal gas equations for a structureful universe consisting of all forms of matters. We have assumed a universe that contains superclusters. Superclusters are then made of clusters. Each cluster can be further divided into smaller ones and so on. We have derived an expression for the entropy of such a universe. Our model is rather independent of the geometry of the intermediate clusters. Our calculations are valid for a non-interacting universe within non-relativistic limits. We suggest that structure formation can reduce the expansion rate of the universe.
How is the Ideal Gas Law Explanatory?
NASA Astrophysics Data System (ADS)
Woody, Andrea I.
2013-07-01
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 insights from these investigations that are salient for pedagogical concerns. Perhaps most importantly, this essay argues that science teachers should be mindful of the normative and prescriptive components of explanatory discourse both in the classroom and in science more generally. Giving attention to this dimension of explanation not only will do justice to the nature of explanatory activity in science but also will support the development of robust reasoning skills in science students while helping them understand an important respect in which science is more than a straightforward collection of empirical facts, and consequently, science education involves more than simply learning them.
Ideal quantum reading of optical memories Michele Dall'Arno
D'Ariano, Giacomo Mauro
Ideal quantum reading of optical memories Michele Dall'Arno Graduate School of Information Science stored in an optical memory with low energy and high accuracy. Focusing on the ideal scenario where noise. Nevertheless, a theoretical analysis of the ideal, i.e. lossless and noiseless, quantum reading provides
Quantum Darwinism in non-ideal environments
Michael Zwolak; H. T. Quan; Wojciech H. Zurek
2010-06-08
Quantum Darwinism provides an information-theoretic framework for the emergence of the objective, classical world from the quantum substrate. The key to this emergence is the proliferation of redundant information throughout the environment where observers can then intercept it. We study this process for a purely decohering interaction when the environment, E, is in a non-ideal (e.g., mixed) initial state. In the case of good decoherence, that is, after the pointer states have been unambiguously selected, the mutual information between the system, S, and an environment fragment, F, is given solely by F's entropy increase. This demonstrates that the environment's capacity for recording the state of S is directly related to its ability to increase its entropy. Environments that remain nearly invariant under the interaction with S, either because they have a large initial entropy or a misaligned initial state, therefore have a diminished ability to acquire information. To elucidate the concept of good decoherence, we show that - when decoherence is not complete - the deviation of the mutual information from F's entropy change is quantified by the quantum discord, i.e., the excess mutual information between S and F is information regarding the initial coherence between pointer states of S. In addition to illustrating these results with a single qubit system interacting with a multi-qubit environment, we find scaling relations for the redundancy of information acquired by the environment that display a universal behavior independent of the initial state of S. Our results demonstrate that Quantum Darwinism is robust with respect to non-ideal initial states of the environment: the environment almost always acquires redundant information about the system but its rate of acquisition can be reduced.
Ideal Gas: properties Collection of atoms/molecules that
Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University
by the same factor P ~ T #12;10 Boyle & Charles & Gay-Lussac IDEAL GAS LAW PV/T = nR n: number of mols) Rewrite ideal gas law: PV/T = NkB where kB=R/NA=1.38x10-23 J/K Boltzmann's constant #12;16 From1 Ideal Gas: properties Collection of atoms/molecules that Â· Exert no force upon each other
Ideal Gas Behavior of a Strongly Coupled Complex (Dusty) Plasma
NASA Astrophysics Data System (ADS)
Oxtoby, Neil P.; Griffith, Elias J.; Durniak, Céline; Ralph, Jason F.; Samsonov, Dmitry
2013-07-01
In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.
Ideal gas behavior of a strongly coupled complex (dusty) plasma.
Oxtoby, Neil P; Griffith, Elias J; Durniak, Céline; Ralph, Jason F; Samsonov, Dmitry
2013-07-01
In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas. PMID:23863006
Pauli paramagnetism of an ideal Fermi gas
Lee, Ye-Ryoung
We show how to use trapped ultracold atoms to measure the magnetic susceptibility of a two-component Fermi gas. The method is illustrated for a noninteracting gas of [superscript 6]Li, using the tunability of interactions ...
Gas lift systems make ideal offshore workers
1999-05-01
With a low initial installation cost and small footprint, gas lift systems are well suited for offshore installations where compressed gas is usually already available. These systems are used on multiple and slimhole completions and handle sandy conditions well. They are also used to kick off wells that will flow naturally once the heavier completion fluids leave the production string. Gas lift itself is a mature workaday technology. Measurement and control of gas flow is an area of intense development in gas lift technology. One new control method involves production of multiple completions through a single wellbore. Typically, gas lift valves are opened and closed through tubing pressure. But downhole measurement technology does not yet yield information good enough for stable gas lift control of multiple completions. Gas lift is proving to be a useful AL technique in conjunction with electric submersible pumps (ESP). Located above the ESP pump, the gas lift can reduce the head and allow greater flow. This is helpful when small casing restricts the size of the downhole ESP pump. Wells can usually be produced by the gas lift alone in case of ESP failure, or by replacing the ESP where schedules, high repair costs or low prices rule out repair.
Irreversibility and decoherence in an ideal gas
Janos Polonyi
2015-02-13
Different models are described where non-interacting particles generate dissipative effective forces by the mixing of infinitely many soft normal modes. The effective action is calculated for these models within the Closed Time Path formalism. This is a well known scheme for quantum systems but its application in classical mechanics presents a new, more unified derivation and treatment of dissipative forces within classical and quantum physics.
Irreversibility and decoherence in an ideal gas
NASA Astrophysics Data System (ADS)
Polonyi, Janos
2015-07-01
Different models are described where non-interacting particles generate dissipative effective forces by the mixing of infinitely many soft normal modes. The effective action is calculated for these models within the Closed Time Path formalism. This is a well known scheme for quantum systems but its application in classical mechanics presents a new, more unified derivation and treatment of dissipative forces within classical and quantum physics.
Irreversibility and decoherence in an ideal gas
Polonyi, Janos
2015-01-01
Different models are described where non-interacting particles generate dissipative effective forces by the mixing of infinitely many soft normal modes. The effective action is calculated for these models within the Closed Time Path formalism. This is a well known scheme for quantum systems but its application in classical mechanics presents a new, more unified derivation and treatment of dissipative forces within classical and quantum physics.
K. Kowalski; J. Rembielinski; K. A. Smolinski
2007-12-18
The Lorentz covariant classical and quantum statistical mechanics and thermodynamics of an ideal relativistic gas of bradyons (particles slower than light), luxons (particles moving with the speed of light) and tachyons (hypothetical particles faster than light) is discussed. The Lorentz covariant formulation is based on the preferred frame approach which among others enables consistent, free of paradoxes description of tachyons. The thermodynamic functions within the covariant approach are obtained both in classical and quantum case.
Kowalski, K.; Rembielinski, J.; Smolinski, K. A. [Department of Theoretical Physics, University of Lodz, ul. Pomorska 149/153, 90-236 Lodz (Poland)
2007-08-15
The Lorentz covariant classical and quantum statistical mechanics and thermodynamics of an ideal relativistic gas of bradyons (particles slower than light), luxons (particles moving with the speed of light), and tachyons (hypothetical particles faster than light) is discussed. The Lorentz covariant formulation is based on the preferred frame approach which among others enables a consistent, free of paradoxes description of tachyons. The thermodynamic functions within the covariant approach are obtained both in the classical and quantum case.
Influence of the Heisenberg Principle on the Ideal Bose Gas
Hua Zheng; Gianluca Giuliani; Aldo Bonasera
2013-03-26
The ideal Bose gas has two major shortcomings: at zero temperature, all the particles 'condense' at zero energy or momentum, thus violating the Heisenberg principle; the second is that the pressure below the critical point is independent of density resulting in zero incompressibility (or infinite isothermal compressibility) which is unphysical. We propose a modification of the ideal Bose gas to take into account the Heisenberg principle. This modification results in a finite (in)compressibility at all temperatures and densities. The main properties of the ideal Bose gas are preserved, i.e. the relation between the critical temperature and density, but the specific heat has a maximum at the critical temperature instead of a discontinuity. Of course interactions are crucial for both cases in order to describe actual physical systems.
Ideal Quantum Gases with Planck Scale Limitations
Collier, Rainer
2015-01-01
A thermodynamic system of non-interacting quantum particles changes its statistical distribution formulas if there is a universal limitation for the size of energetic quantum leaps (magnitude of quantum leaps smaller than Planck energy). By means of a restriction of the a priori equiprobability postulate one can reach a thermodynamic foundation of these corrected distribution formulas. The number of microstates is determined by means of a suitable counting method and combined with thermodynamics via the Boltzmann principle. The result is that, for particle energies that come close to the Planck energy, the thermodynamic difference between fermion and boson distribution vanishes. Both distributions then approximate a Boltzmann distribution. The wave and particle character of the quantum particles, too, can be influenced by choosing the size of the temperature and particle energy parameters relative to the Planck energy, as you can see from the associated fluctuation formulas. In the case of non-relativistic de...
Ideal Quantum Gases with Planck Scale Limitations
Rainer Collier
2015-03-14
A thermodynamic system of non-interacting quantum particles changes its statistical distribution formulas if there is a universal limitation for the size of energetic quantum leaps (magnitude of quantum leaps smaller than Planck energy). By means of a restriction of the a priori equiprobability postulate one can reach a thermodynamic foundation of these corrected distribution formulas. The number of microstates is determined by means of a suitable counting method and combined with thermodynamics via the Boltzmann principle. The result is that, for particle energies that come close to the Planck energy, the thermodynamic difference between fermion and boson distribution vanishes. Both distributions then approximate a Boltzmann distribution. The wave and particle character of the quantum particles, too, can be influenced by choosing the size of the temperature and particle energy parameters relative to the Planck energy, as you can see from the associated fluctuation formulas. In the case of non-relativistic degeneration, the critical parameters Fermi momentum (fermions) and Einstein temperature (bosons) vanish as soon as the rest energy of the quantum particles reaches the Planck energy. For the Bose-Einstein condensation there exists, in the condensation range, a finite upper limit for the number of particles in the ground state, which is determined by the ratio of Planck mass to the rest mass of the quantum particles. In the relativistic high-temperature range, the energy densities of photon and neutrino radiation have finite limit values, which is of interest with regard to the start of cosmic expansion.
Experimental verification of Boyle's law and the ideal gas law
NASA Astrophysics Data System (ADS)
Trifonov Ivanov, Dragia
2007-03-01
We offer two new experiments concerning the experimental verification of Boyle's law and the ideal gas law. To carry out the experiments we use glass tubes, water, a syringe and a metal manometer. The pressure of the saturated water vapour is taken into consideration. For educational purposes, the experiments are characterized by their accessibility and the considerable precision of results.
Thermodynamics of Ideal Gas in Doubly Special Relativity
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.
Experimental Verification of Boyle's Law and the Ideal Gas Law
ERIC Educational Resources Information Center
Ivanov, Dragia Trifonov
2007-01-01
Two new experiments are offered concerning the experimental verification of Boyle's law and the ideal gas law. To carry out the experiments, glass tubes, water, a syringe and a metal manometer are used. The pressure of the saturated water vapour is taken into consideration. For educational purposes, the experiments are characterized by their…
From Free Expansion to Abrupt Compression of an Ideal Gas
ERIC Educational Resources Information Center
Anacleto, Joaquim; Pereira, Mario G.
2009-01-01
Using macroscopic thermodynamics, the general law for adiabatic processes carried out by an ideal gas was studied. It was shown that the process reversibility is characterized by the adiabatic reversibility coefficient r, in the range 0 [less than or equal] r [less than or equal] 1 for expansions and r [greater than or equal] 1 for compressions.…
Implications of Minimal Length Scale on the Statistical Mechanics of Ideal Gas
Kourosh Nozari; S. H. Mehdipour
2006-10-21
Several alternative approaches to quantum gravity problem suggest the modification of the {\\it fundamental volume $\\omega_{0}$} of the accessible phase space for representative points. This modified fundamental volume has a novel momentum dependence. In this paper, we study the effects of this modification on the thermodynamics of an ideal gas within the microcanonical ensemble and using the generalized uncertainty principle(GUP). Although the induced modifications are important only in quantum gravity era, possible experimental manifestation of these effects may provides strong support for underlying quantum gravity proposal.
Condensation of an ideal gas with intermediate statistics on the horizon
NASA Astrophysics Data System (ADS)
Zare, Somayeh; Raissi, Zahra; Mohammadzadeh, Hosein; Mirza, Behrouz
2012-09-01
We consider a boson gas on the stretched horizon of the Schwartzschild and Kerr black holes. It is shown that the gas is in a Bose-Einstein condensed state with the Hawking temperature T c = T H if the particle number of the system be equal to the number of quantum bits of space-time N ˜eq{A}/{lp2}. Entropy of the gas is proportional to the area of the horizon ( A) by construction. For a more realistic model of quantum degrees of freedom on the horizon, we should presumably consider interacting bosons (gravitons). An ideal gas with intermediate statistics could be considered as an effective theory for interacting bosons. This analysis shows that we may obtain a correct entropy just by a suitable choice of parameter in the intermediate statistics.
Relativistic ideal Fermi gas at zero temperature and preferred frame
Kowalski, K.; Rembielinski, J.; Smolinski, K. A. [Department of Theoretical Physics, University of Lodz, ul. Pomorska 149/153, 90-236 Lodz (Poland)
2007-12-15
We discuss the limit T{yields}0 of the relativistic ideal Fermi gas of luxons (particles moving with the speed of light) and tachyons (hypothetical particles faster than light) based on observations of our recent paper: K. Kowalski, J. Rembielinski, and K. A. Smolinski, Phys. Rev. D 76, 045018 (2007). For bradyons this limit is in fact the nonrelativistic one and therefore it is not studied herein.
Quantum state of an ideal propagating laser field.
van Enk, S J; Fuchs, Christopher A
2002-01-14
We give a quantum information-theoretic description of an ideal propagating cw laser field and reinterpret typical quantum-optical experiments in light of this. In particular, we show that, contrary to recent claims [T. Rudolph and B. C. Sanders, Phys. Rev. Lett. 87, 077903 (2001)], a conventional laser can be used for quantum teleportation with continuous variables and for generating continuous-variable entanglement. Optical coherence is not required, but phase coherence is. We also show that coherent states play a privileged role in the description of laser light. PMID:11801038
Thermodynamics of a statistically interacting quantum gas in D dimensions
NASA Astrophysics Data System (ADS)
Potter, Geoffrey G.; Müller, Gerhard; Karbach, Michael
2007-12-01
We present the exact thermodynamics (isochores, isotherms, isobars, response functions) of a statistically interacting quantum gas in D dimensions. The results in D=1 are those of the thermodynamic Bethe ansatz for the nonlinear Schrödinger model, a gas with repulsive two-body contact potential. In all dimensions the ideal boson and fermion gases are recovered in the weak-coupling and strong-coupling limits, respectively. For all nonzero couplings ideal fermion gas behavior emerges for D?1 and, in the limit D?? , a phase transition occurs at T>0 . Significant deviations from ideal quantum gas behavior are found for intermediate coupling and finite D .
Primitive ideals in quantum Schubert cells: dimension of the strata
Bell, Jason; Launois, Stéphane
2010-01-01
The aim of this paper is to study the representation theory of quantum Schubert cells. Let $\\g$ be a simple complex Lie algebra. To each element $w$ of the Weyl group $W$ of $\\g$, De Concini, Kac and Procesi have attached a subalgebra $U_q[w]$ of the quantised enveloping algebra $U_q(\\g)$. Recently, Yakimov showed that these algebras can be interpreted as the quantum Schubert cells on quantum flag manifolds. In this paper, we study the primitive ideals of $U_q[w]$. More precisely, it follows from the Stratification Theorem of Goodearl and Letzter that the primitive spectrum of $U_q[w]$ admits a stratification indexed by those primes that are invariant under a natural torus action. Moreover each stratum is homeomorphic to the spectrum of maximal ideals of a torus. The main result of this paper gives an explicit formula for the dimension of the stratum associated to a given torus-invariant prime.
Measurement of optical Feshbach resonances in an ideal gas.
Blatt, S; Nicholson, T L; Bloom, B J; Williams, J R; Thomsen, J W; Julienne, P S; Ye, J
2011-08-12
Using a narrow intercombination line in alkaline earth atoms to mitigate large inelastic losses, we explore the optical Feshbach resonance effect in an ultracold gas of bosonic (88)Sr. A systematic measurement of three resonances allows precise determinations of the optical Feshbach resonance strength and scaling law, in agreement with coupled-channel theory. Resonant enhancement of the complex scattering length leads to thermalization mediated by elastic and inelastic collisions in an otherwise ideal gas. Optical Feshbach resonance could be used to control atomic interactions with high spatial and temporal resolution. PMID:21902391
Thermal transport through non-ideal Andreev quantum dots
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.
Kåre Olaussen; Asle Sudbø
2015-02-04
The virial expansion of ideal quantum gases reveals some interesting and amusing properties when considered as a function of dimensionality $d$. In particular, the convergence radius $\\rho_c(d)$ of the expansion is particulary large at {\\em exactly\\/} $d=3$ dimensions, $\\rho_c(3) = 7.1068\\ldots \\times \\lim_{d\\to3} \\rho_c(d)$. The same phenomenon occurs in a few other special (non-integer) dimensions. We explain the origin of these facts, and discuss more generally the structure of singularities governing the asymptotic behavior of the ideal gas virial expansion.
Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas
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 ...
Largetime behavior of solutions to the equations of a onedimensional viscous polytropic ideal gas in
LargeÂtime behavior of solutions to the equations of a oneÂdimensional viscous polytropic ideal gas and initial boundary value problems for a oneÂ dimensional viscous polytropic ideal gas in unbounded domains to the equations of motion of a oneÂdimensional viscous polytropic ideal gas in unbounded domains. The motion
CHAPTER 5 -SYSTEMS UNDER PRESSURE 5.1 Ideal gas law
Boal, David
CHAPTER 5 - SYSTEMS UNDER PRESSURE 5.1 Ideal gas law The quantitative study of gases goes back more as it is heated. These two observations are combined into an expression known as the ideal gas law, which weB is Boltzmann's constant (see Chap. 4). It is more conventional to express the ideal gas law in terms
M. Bahrami ENSC 461 (S 11) Tutorial 1 1 ENSC 461 Tutorial, Week#2 Ideal Gas
Bahrami, Majid
) To solve for the final pressure of the system we can make use of the Ideal Gas Law to express the pressureM. Bahrami ENSC 461 (S 11) Tutorial 1 1 ENSC 461 Tutorial, Week#2 Ideal Gas Consider a rigid from the tank to the surroundings. 3) Air is modelled as an ideal gas with constant specific heats over
Winokur, Michael
. HC-1 The Ideal Gas Law and Absolute Zero: In this lab you will do Experiments I and II. In ExperimentHC-1 Ideal Gas and Absolute Zero Name_______________________ Lab Worksheet Group member names;HC-1 Ideal Gas and Absolute Zero Name_______________________ Lab Worksheet 3 4) Now compare
Effect of the Minimal Length on Bose-Einstein Condensation in the Relativistic Ideal Bose Gas
Xiuming Zhang; Chi Tian
2014-10-10
Based on the generalized uncertainty principle (GUP), the critical temperature and the Helmholtz free energy of Bose-Einstein condensation (BEC) in the relativistic ideal Bose gas are investigated. At the non-relativistic limit and the ultra-relativistic limit, we calculate the analytical form of the shifts of the critical temperature and the Helmholtz free energy caused by weak quantum gravitational effects. The exact numerical results of these shifts are obtained. Quantum gravity effects lift the critical temperature of BEC. By measuring the shift of the critical temperature, we can constrain the deformation parameter $\\beta_0$. Furthermore, at lower densities, omitting quantum gravitational effects may lead to a metastable state while at sufficiently high densities, quantum gravitational effects tend to make BEC unstable. Using the numerical methods, the stable-unstable transition temperature is found.
NASA Astrophysics Data System (ADS)
Dorofeeva, Olga V.; Vishnevskiy, Yuriy V.; Rykov, Anatolii N.; Karasev, Nikolai M.; Moiseeva, Natalia F.; Vilkov, Lev V.; Oberhammer, Heinz
2006-05-01
3-Fluoroanisole (3-FA) and 3,5-difluoroanisole (3,5-DFA) have been studied by gas-phase electron diffraction, ab initio (HF and MP2), and density functional theory (B3LYP) calculations. Both molecules have a planar heavy atom skeleton. 3,5-DFA exists as a single conformer of Cs symmetry, whereas 3-FA exists as a mixture of two planar conformers of Cs symmetry with the syn form (the O-CH 3 bond is oriented toward the fluorine atom) being 0.1-0.2 kcal/mol lower in energy than the anti form (the O-CH 3 bond is oriented away from the fluorine atom). From the experimental scattering intensities the following geometric parameters ( ra distances and ? ? angles with 3? uncertainties) were derived for 3,5-DFA: r(C-C) av=1.391(2) Å, r(C Ph-O)=1.359(13) Å, r(C Me-O)=1.427(19) Å, r(C-F) av=1.350(6) Å, ?C-C-C=116.0-123.6°, ?C-O-C=118.7(12)°, ?C2-C1-O=114.9(10)°, ?C6-C1-O=124.9(10)°, ?(C-C-F) av=118.4(17)°, and for 3-FA, syn conformer: r(C-C) av=1.393(3) Å, r(C Ph-O)=1.364(13) Å, r(C Me-O)=1.423(14) Å, r(C-F)=1.348(9) Å, ?C-C-C=117.7-123.1°, ?C-O-C=118.4(11)°, ?C2-C1-O=124.7(17)°, ?C6-C1-O=115.1(17)°, ?C2-C3-F=118.0(24)°. The mole fractions of the syn and anti conformers were found to be 0.55(17) and 0.45, respectively, in good agreement with the theoretical prediction. Ideal gas thermodynamic functions, S°( T), Cp°(T), H°( T)- H°(0), for anisole, 3-FA, and 3,5-DFA were obtained on the basis of B3LYP calculations. Enthalpies of formations, ? fH298°, were calculated using a Gaussian-3X (G3X) method and the method of isodesmic reactions. Calculated values of Cp°(T) and ? fH298° for anisole are in good agreement with experimental data.
Microeconomics of the ideal gas like market models
NASA Astrophysics Data System (ADS)
Chakrabarti, Anindya S.; Chakrabarti, Bikas K.
2009-10-01
We develop a framework based on microeconomic theory from which the ideal gas like market models can be addressed. A kinetic exchange model based on that framework is proposed and its distributional features have been studied by considering its moments. Next, we derive the moments of the CC model (Eur. Phys. J. B 17 (2000) 167) as well. Some precise solutions are obtained which conform with the solutions obtained earlier. Finally, an output market is introduced with global price determination in the model with some necessary modifications.
Convection in an ideal gas at high Rayleigh numbers.
Tilgner, A
2011-08-01
Numerical simulations of convection in a layer filled with ideal gas are presented. The control parameters are chosen such that there is a significant variation of density of the gas in going from the bottom to the top of the layer. The relations between the Rayleigh, Peclet, and Nusselt numbers depend on the density stratification. It is proposed to use a data reduction which accounts for the variable density by introducing into the scaling laws an effective density. The relevant density is the geometric mean of the maximum and minimum densities in the layer. A good fit to the data is then obtained with power laws with the same exponent as for fluids in the Boussinesq limit. Two relations connect the top and bottom boundary layers: The kinetic energy densities computed from free fall velocities are equal at the top and bottom, and the products of free fall velocities and maximum horizontal velocities are equal for both boundaries. PMID:21929106
Convection in an ideal gas at high Rayleigh numbers
Tilgner, A
2011-01-01
Numerical simulations of convection in a layer filled with ideal gas are presented. The control parameters are chosen such that there is a significant variation of density of the gas in going from the bottom to the top of the layer. The relations between the Rayleigh, Peclet and Nusselt numbers depend on the density stratification. It is proposed to use a data reduction which accounts for the variable density by introducing into the scaling laws an effective density. The relevant density is the geometric mean of the maximum and minimum densities in the layer. A good fit to the data is then obtained with power laws with the same exponent as for fluids in the Boussinesq limit. Two relations connect the top and bottom boundary layers: The kinetic energy densities computed from free fall velocities are equal at the top and bottom, and the products of free fall velocities and maximum horizontal velocities are equal for both boundaries.
Quantum Algorithms for Unit Group and principal ideal problem
Hong Wang; Zhi Ma
2010-09-01
Computing the unit group and solving the principal ideal problem for a number field are two of the main tasks in computational algebraic number theory. This paper proposes efficient quantum algorithms for these two problems when the number field has constant degree. We improve these algorithms proposed by Hallgren by using a period function which is not one-to-one on its fundamental period. Furthermore, given access to a function which encodes the lattice, a new method to compute the basis of an unknown real-valued lattice is presented.
Eight Methods for Determining R in the Ideal Gas Law
Macnaughton, Donald B
2007-01-01
The ideal gas law of physics and chemistry says that PV = nRT. This law is a statement of the relationship between four variables that reflect key properties of a quantity of gas: P (pressure), V (volume), n (amount), and T (temperature). The law enables us to make accurate predictions of the value of any one of the four variables from the values of the other three. The term R (called the "molar gas constant") is the sole "parameter" of the equation. R is a fixed number that has been shown through experiments to have a value of approximately 8.314472. Eight methods are available to analyze the data from a relevant experiment to determine the value of R. These methods are specific instances of eight general methods that scientists use to determine the value(s) of the parameter(s) of the model equation of any relationship between variables. An apparent slight error in the official value of R is discussed.
Finite size effect on classical ideal gas revisited
NASA Astrophysics Data System (ADS)
Ghosh, P.; Ghosh, S.; Mitra, J.; Bera, N.
2015-09-01
Finite size effects on classical ideal gas are revisited. The micro-canonical partition function for a collection of ideal particles confined in a box is evaluated using Euler–Maclaurin’s as well as Poisson's summation formula. In Poisson's summation formula there are some exponential terms which are absent in Euler–Maclaurin’s formula. In the thermodynamic limit the exponential correction is negligibly small but in the macro/nano dimensions and at low temperatures they may have a great significance. The consequences of finite size effects have been illustrated by redoing the calculations in one and three dimensions keeping the exponential corrections. Global and local thermodynamic properties, diffusion driven by the finite size effect, and effect on speed of sound have been discussed. Thermo-size effects, similar to thermoelectric effects, have been described in detail and may be a theoretical basis with which to design nano-scaled devices. This paper can also be very helpful for undergraduate and graduate students in physics and chemistry as an instructive exercise for a good course in statistical mechanics.
MÃ¼ller, Markus
Ideal quantum glass transitions: Many-body localization without quenched disorder M. Schiulaz and M://scitation.aip.org/termsconditions. Downloaded to IP: 87.102.243.104 On: Mon, 18 Aug 2014 14:07:47 #12;Ideal quantum glass transitions: many classical systems, where the existence of such an ideal glass transition remains a controversial issue
First Law of Thermodynamics Two closed thermodynamic cycles for an ideal gas
Winokur, Michael
1 First Law of Thermodynamics Two closed thermodynamic cycles for an ideal gas are depicted-static if: 1. They happen slowly. It is reasonable to use the ideal-gas model in this problem on the pV diagram. Imagine processing the gas clockwise through Cycle 1 once. Determine whether the change
Marcoen J. T. F. Cabbolet
2015-09-13
Referring to the 18th century idealism of George Berkeley in which an object exists if and only if it is observed, this note shows that orthodox quantum mechanics (OQM) entails a Berkelian idealism regarding properties (BIRP): a quantum `has' a property X with quantitative value x if and only if the property X has just been measured with outcome x. It is then impossible to recontextualize GR's principle of curvature in any quantum framework that implies this BIRP, for a quantum cannot curve space-time if it doesn't have a definite energy - which is supposed to be the cause of curvature - in absence of observation to begin with. Concluding, it is ruled out that a quantum theory of gravity, in which GR's principle of curvature is built in as a fundamental physical principle, can be developed in any framework implying this BIRP.
High School Forum. The Solution: "Derivation of the Ideal Gas Law."
ERIC Educational Resources Information Center
Herron, J. Dudley, Ed.
1980-01-01
Presents responses to an earlier report concerning a procedure for the derivation of the Ideal Gas Law from Charles', Boyle's, and other gas laws. Logic errors and solutions that work are discussed. (CS)
Steady flow around a plane cascade by an ideal gas
NASA Astrophysics Data System (ADS)
Kraiko, A. N.; Shironosov, V. A.; Shironosova, E. Ya.
1984-11-01
The steady separation-free flow around a flat cascade by an ideal gas is discussed. Most of the attention is devoted to blocking regimes with a supersonic velocity in the entire flow and its subsonic component normal to the front of the cascade. A “directing action” of the cascade (the direction of the velocity and the Mach number of the advancing flow turn out to be related) is exhibited in these regimes which is a consequence of an independence of the flow in front of the cascade of the conditions behind it [1 5]. The most widespread method of their calculation [3, 4, 6] is based on the method of characteristics with establishment of the flow outside the cascade in a timelike coordinate. Although the integrated conservation laws also permit finding the parameters at infinity, the numerical construction of as long-range fields as desired with periodic sequences of attenuating discontinuities is practically impossible. The approximation of nonlinear acoustics (ANA) [7, 8] is justified here, as it is very effective in such problems [8 12]. A combination of ANA, the integrated conservation laws, and establishment in a calculation according to [13, 14] with isolation of the discontinuities has been realized in [5] for the construction of a solution on the entrance section of a cascade and everywhere in front of it. Below the method of [5] is extended to the entire flow and simplified even more. The flow on the entrance section of the cascade is, just as in [3], found in the approximation of a simple wave, in the rest of it and in a finite strip behind it-the flow is found with the help of the “straight-through” version of the scheme of [13, 14], and in the “long-range field”-in the ANA. A simpler version is proposed. In it ANA is applied outside the cascade and the linear theory is applied inside the cascade. Examples of the calculations are given. Similarity laws are formulated for all the regimes of streamline flow.
A cryogenic quantum gas scanning magnetic microscope
NASA Astrophysics Data System (ADS)
Turner, Richard; Naides, Matthew; Lai, Ruby; Disciacca, Jack; Lev, Benjamin
2014-05-01
Improved measurements of strongly correlated and topologically non-trivial systems open the path to a better fundamental understanding of these materials as well as the possibility for predictive design of new materials. We are working to demonstrate atom chip trapping of quantum gases to enable single-shot, large area imaging of electronic transport through these materials via detection of magnetic flux at the 10- 7 flux quantum level and below. Using the exquisite sensitivity of ultracold atoms in the form of either an atomic clock or Bose-Einstein condensate, the cryogenic atom chip technology we have recently demonstrated will provide a magnetic flux detection capability that surpasses other techniques while allowing sample temperatures spanning < 10 K to room temperature. We will report on experimental progress toward developing this novel quantum gas scanning magnetic microscope and describe our recent proposal to image topologically protected transport through a non-ideal topological insulator in a relatively model-independent fashion.
A cryogenic quantum gas scanning magnetic microscope
NASA Astrophysics Data System (ADS)
Disciacca, Jack; Naides, Matthew; Turner, Richard; Lai, Ruby; Lev, Benjamin
2014-03-01
Improved measurements of strongly correlated and topologically non-trivial systems open the path to a better fundamental understanding of these materials as well as the possibility for predictive design of new materials. We are working to demonstrate atom chip trapping of quantum gases to enable single-shot, large area imaging of electronic transport through these materials via detection of magnetic flux at the 10-7 flux quantum level and below. Using the exquisite sensitivity of ultracold atoms in the form of either an atomic clock or Bose-Einstein condensate, the cryogenic atom chip technology we have recently demonstrated will provide a magnetic flux detection capability that surpasses other techniques while allowing sample temperatures spanning <10 K to room temperature. We will report on experimental progress toward developing this novel quantum gas scanning magnetic microscope and describe our recent proposal to image topologically protected transport through a non-ideal topological insulator in a relatively model-independent fashion.
A cryogenic quantum gas scanning magnetic microscope
NASA Astrophysics Data System (ADS)
Turner, Richard; Naides, Matthew; Lai, Ruby; Disciacca, Jack; Lev, Benjamin
2014-05-01
Improved measurements of strongly correlated and topologically non-trivial systems open the path to a better fundamental understanding of these materials as well as the possibility for predictive design of new materials. We are working to demonstrate atom chip trapping of quantum gases to enable single-shot, large area imaging of electronic transport through these materials via detection of magnetic flux at the 10-7 flux quantum level and below. Using the exquisite sensitivity of ultracold atoms in the form of either an atomic clock or Bose-Einstein condensate, the cryogenic atom chip technology we have recently demonstrated will provide a magnetic flux detection capability that surpasses other techniques while allowing sample temperatures spanning < 10 K to room temperature. We will report on experimental progress toward developing this novel quantum gas scanning magnetic microscope and describe our recent proposal to image topologically protected transport through a non-ideal topological insulator in a relatively model-independent fashion.
Boal, David
The ideal gas law describes most gases fairly well at very low density, where the intermolecular separation. Virial expansion The ideal gas law can be trivially rewritten as P / kBT = N / V. (6.1) Although to the ideal gas law. Because it is more common to Chapter 6 - Periodic boundaries 78 Â©1997 by David Boal
Reynolds and Favre-averaged rapid distortion theory for compressible, ideal-gas turbulence
Lavin, Tucker Alan
2007-09-17
Compressible ideal-gas turbulence subjected to homogeneous shear is investigated at the rapid distortion limit. Specific issues addressed are (i) the interaction between kinetic and internal energies and role of pressure-dilatation; (ii...
40 CFR 1065.645 - Amount of water in an ideal gas.
Code of Federal Regulations, 2011 CFR
2011-07-01
...calculations. Use the equation for the vapor pressure of water in paragraph (a) of this...an ideal gas. p H20 = water vapor pressure at the measured dewpoint...relative humidity. p H20 = water vapor pressure at 100%...
40 CFR 1065.645 - Amount of water in an ideal gas.
Code of Federal Regulations, 2012 CFR
2012-07-01
...calculations. Use the equation for the vapor pressure of water in paragraph (a) of this...an ideal gas. p H20 = water vapor pressure at the measured dewpoint...relative humidity. p H20 = water vapor pressure at 100%...
40 CFR 1065.645 - Amount of water in an ideal gas.
Code of Federal Regulations, 2010 CFR
2010-07-01
...calculations. Use the equation for the vapor pressure of water in paragraph (a) of this...an ideal gas. p H20 = water vapor pressure at the measured dewpoint...relative humidity. p H20 = water vapor pressure at 100%...
40 CFR 1065.645 - Amount of water in an ideal gas.
Code of Federal Regulations, 2013 CFR
2013-07-01
...calculations. Use the equation for the vapor pressure of water in paragraph (a) of this...an ideal gas. p H20 = water vapor pressure at the measured dewpoint...relative humidity. p H20 = water vapor pressure at 100%...
Student understanding of the ideal gas law, Part II: A microscopic perspective
NASA Astrophysics Data System (ADS)
Kautz, Christian H.; Heron, Paula R. L.; Shaffer, Peter S.; McDermott, Lillian C.
2005-11-01
Evidence from research indicates that many undergraduate science and engineering majors have seriously flawed microscopic models for the pressure and temperature in an ideal gas. In the investigation described in this paper, some common mistaken ideas about microscopic processes were identified. Examples illustrate the use of this information in the design of instruction that helped improve student understanding of the ideal gas law, especially its substance independence. Some broader implications of this study for the teaching of thermal physics are noted.
A Quantum Gas Microscope for Ultracold Fermions
NASA Astrophysics Data System (ADS)
Cheuk, Lawrence; Nichols, Matthew; Okan, Melih; Lompe, Thomas; Zwierlein, Martin
2015-05-01
Ultracold atoms in optical lattices are ideal systems to study model quantum many-body physics in a clean and well-controlled environment. Experiments at Harvard and MPQ Munich using bosonic 87Rb atoms in optical lattices have demonstrated the ability to detect and address atoms at the single-site level, revealing microscopic density distributions and correlations difficult to extract from bulk measurements. The goal of our experiment is to achieve such single-site control for a quantum gas of fermions. This allows for exploring physics that arise in strongly-correlated fermionic systems. In this talk, we present results of site-resolved fluorescent imaging of fermionic 40K with high fidelity.
Fluctuations in an Ideal Modified Bosonic Gas Trapped in an Arbitrary 3-dim Power-Law Potential
Castellanos, E
2012-01-01
We analyze the number of particle fluctuations within the semiclassical approximation of an ideal bosonic gas with an anomalous single--particle dispersion relation suggested in several quantum--gravity approaches trapped in a generic 3--dimensional power--law potential as a criterium of thermodynamic stability for these systems. We show that the analysis of the fluctuations in the number of particles caused by a deformation in the dispersion relation, leads to an observable consequence associated to the thermodynamic stability for a specific choice of the trap parameters. Additionally, we deduce the shift in the critical temperature in the thermodynamic limit associated with this "modified bosonic gas" and show that this shift expressed in function of the number of particles, can be used as an amplifier for some quantum gravity manifestations for stable systems.
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.
Kheruntsyan, Karen
2012-01-01
PHYSICAL REVIEW A 86, 023618 (2012) Two-body anticorrelation in a harmonically trapped ideal Bose in the second-order coherence function of a partially condensed ideal Bose gas in harmonic confinement-number fluctuation catastrophe of the ideal Bose gas. The anticorrelation is most pronounced in highly anisotropic
Dettmann, Carl
Statistical mechanics problem sheet 3 1. Does an ideal gas satisfy the third law of thermodynamics of an ideal gas. 4. Consider an atmosphere containing two species with molecular masses m1, m2 and effective degrees of freedom d1, d2. Assume ideal conditions, ie no interactions between the particles. (a) Show
Anomalous heat conduction in a one-dimensional ideal gas.
Casati, Giulio; Prosen, Tomaz
2003-01-01
We provide firm convincing evidence that the energy transport in a one-dimensional gas of elastically colliding free particles of unequal masses is anomalous, i.e., the Fourier law does not hold. Our conclusions are confirmed by a theoretical and numerical analysis based on a Green-Kubo-type approach specialized to momentum-conserving lattices. PMID:12636549
Ultracold strongly coupled gas: A near-ideal liquid
NASA Astrophysics Data System (ADS)
Gelman, Boris A.; Shuryak, Edward V.; Zahed, Ismail
2005-10-01
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 ? : ?=?n?? , where ?? 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 ???(6?)-1 . We relate the damping of low-frequency density oscillations of ultracold optically trapped Li6 atoms to viscosity and find that the value of the coefficient ?? 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.
Ideal Shear Strength of a Quantum Crystal Edgar Josu Landinez Borda,1,
Cai, Wei
-859 Campinas, São Paulo, Brazil 2 Department of Mechanical Engineering, Stanford University, Stanford in which the quantum- mechanical effects are mostly negligible [2,3,1418]. Recently, however, there hasIdeal Shear Strength of a Quantum Crystal Edgar Josué Landinez Borda,1, Wei Cai,2, and Maurice de
Performance of a multilevel quantum heat engine of an ideal N-particle Fermi system.
Wang, Rui; Wang, Jianhui; He, Jizhou; Ma, Yongli
2012-08-01
We generalize the quantum heat engine (QHE) model which was first proposed by Bender et al. [J. Phys. A 33, 4427 (2000)] to the case in which an ideal Fermi gas with an arbitrary number N of particles in a box trap is used as the working substance. Besides two quantum adiabatic processes, the engine model contains two isoenergetic processes, during which the particles are coupled to energy baths at a high constant energy E(h) and a low constant energy E(c), respectively. Directly employing the finite-time thermodynamics, we find that the power output is enhanced by increasing particle number N (or decreasing minimum trap size L(A)) for given L(A) (or N), without reduction in the efficiency. By use of global optimization, the efficiency at possible maximum power output (EPMP) is found to be universal and independent of any parameter contained in the engine model. For an engine model with any particle-number N, the efficiency at maximum power output (EMP) can be determined under the condition that it should be closest to the EPMP. Moreover, we extend the heat engine to a more general multilevel engine model with an arbitrary 1D power-law potential. Comparison between our engine model and the Carnot cycle shows that, under the same conditions, the efficiency ? = 1 - E(c)/E(h) of the engine cycle is bounded from above the Carnot value ?(c) =1 - T(c)/T(h). PMID:23005748
Student understanding of the ideal gas law, Part I: A macroscopic perspective
NASA Astrophysics Data System (ADS)
Kautz, Christian H.; Heron, Paula R. L.; Loverude, Michael E.; McDermott, Lillian C.
2005-11-01
Our findings from a long-term investigation indicate that many students cannot properly interpret or apply the ideal gas law after instruction in introductory physics and chemistry as well as more advanced courses. The emphasis in this paper is on the concepts of pressure, volume, and temperature at the macroscopic level. We describe some serious conceptual and reasoning difficulties that we have identified. Results from our research were applied in the design of a curriculum that has helped improve student understanding of the ideal gas law.
Ideal quantum glass transitions: Many-body localization without quenched disorder
Schiulaz, M. [International School for Advanced Studies (SISSA), via Bonomea 265, 34136 Trieste (Italy); Müller, M. [The Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste (Italy)
2014-08-20
We explore the possibility for translationally invariant quantum many-body systems to undergo a dynamical glass transition, at which ergodicity and translational invariance break down spontaneously, driven entirely by quantum effects. In contrast to analogous classical systems, where the existence of such an ideal glass transition remains a controversial issue, a genuine phase transition is predicted in the quantum regime. This ideal quantum glass transition can be regarded as a many-body localization transition due to self-generated disorder. Despite their lack of thermalization, these disorder-free quantum glasses do not possess an extensive set of local conserved operators, unlike what is conjectured for many-body localized systems with strong quenched disorder.
Seeing zeros of random polynomials: quantized vortices in the ideal Bose gas
Yvan Castin; Zoran Hadzibabic; Sabine Stock; Jean Dalibard; Sandro Stringari
2005-11-14
We propose a physical system allowing one to experimentally observe the distribution of the complex zeros of a random polynomial. We consider a degenerate, rotating, quasi-ideal atomic Bose gas prepared in the lowest Landau level. Thermal fluctuations provide the randomness of the bosonic field and of the locations of the vortex cores. These vortices can be mapped to zeros of random polynomials, and observed in the density profile of the gas.
Cooking under Pressure: Applying the Ideal Gas Law in the Kitchen
ERIC Educational Resources Information Center
Chen, Ling; Anderson, Jennifer Y.; Wang, Diane R.
2010-01-01
This case study uses a daily cooking scenario to demonstrate how the boiling point of water is directly related to the external pressures in order to reinforce the concepts of boiling and boiling point, apply ideal gas law, and relate chemical reaction rates with temperatures. It also extends its teaching to autoclaves used to destroy…
Statistical relativistic temperature transformation for ideal gas of bradyons, luxons and tachyons
Felipe Asenjo; Cristian A. Farías; Pablo S. Moya
2009-03-05
Starting from a microcanonical statistical approach and special relativity, the relativistic transformations for temperature and pressure for an ideal gas of bradyons, luxons or tachyons is found. These transformations are in agreement with the three laws of thermodynamic and our temperature transformation is the same as Ott's. Besides, it is shown that the thermodynamic $dS$ element is Lorentz-invariant.
40 CFR 1065.645 - Amount of water in an ideal gas.
Code of Federal Regulations, 2014 CFR
2014-07-01
...in an ideal gas. p H20 = water vapor pressure at the measured dewpoint...relative humidity. p H20 = water vapor pressure at 100% relative humidity...p H2Oscaled , which is the water vapor pressure scaled to the...
Simple ideal gas model of the Pavlovskii high-explosive opening switch
T. J. Tucker
1983-01-01
The behavior of the Pavlovskii type high-explosive opening switch is modeled using an ideal gas formulation. It is shown that this simple 1 dimensional model agrees with experiment during early arc compression but that at later times the process exhibits a more complex behavior, resulting from turbulent mixing.
Case Study: Cooking Under Pressure--Applying the Ideal Gas Law in the Kitchen
NSDL National Science Digital Library
Diane R. Wang
2010-11-01
This case study uses a daily cooking scenario to demonstrate how the boiling point of water is directly related to the external pressures in order to reinforce the concepts of boiling and boiling point, apply ideal gas law, and relate chemical reaction ra
Kinetic Models for Adiabatic Reversible Expansion of a Monatomic Ideal Gas.
ERIC Educational Resources Information Center
Chang, On-Kok
1983-01-01
A fixed amount of an ideal gas is confined in an adiabatic cylinder and piston device. The relation between temperature and volume in initial/final phases can be derived from the first law of thermodynamics. However, the relation can also be derived based on kinetic models. Several of these models are discussed. (JN)
NASA Astrophysics Data System (ADS)
Qin, Fang; Wen, Wen; Chen, Ji-Sheng
2014-07-01
The thermal and electrical transport properties of an ideal anyon gas within fractional exclusion statistics are studied. By solving the Boltzmann equation with the relaxation-time approximation, the analytical expressions for the thermal and electrical conductivities of a three-dimensional ideal anyon gas are given. The low-temperature expressions for the two conductivities are obtained by using the Sommerfeld expansion. It is found that the Wiedemann—Franz law should be modified by the higher-order temperature terms, which depend on the statistical parameter g for a charged anyon gas. Neglecting the higher-order terms of temperature, the Wiedemann—Franz law is respected, which gives the Lorenz number. The Lorenz number is a function of the statistical parameter g.
ERIC Educational Resources Information Center
Smith, Brent
2002-01-01
Describes equations of state as a supplement to an introductory thermodynamics undergraduate course. Uses rubber-elastic materials (REM) which have strong analogies to the concept of an ideal gas and explains the molar basis of REM. Provides examples of the analogies between ideal gas and REM and mathematical analogies. (Contains 22 references.)…
ERIC Educational Resources Information Center
Smith, Brent
2002-01-01
Describes the laws of thermodynamics as a supplement to an introductory thermodynamics undergraduate course. Uses rubber-elastic materials (REM) which have strong analogies to the concept of ideal gas. Provides examples of the analogies between ideal gas and REM and mathematical analogies. (YDS)
NASA Astrophysics Data System (ADS)
Kreis, K.; Fogarty, A. C.; Kremer, K.; Potestio, R.
2015-06-01
In adaptive resolution simulations, molecular fluids are modeled employing different levels of resolution in different subregions of the system. When traveling from one region to the other, particles change their resolution on the fly. One of the main advantages of such approaches is the computational efficiency gained in the coarse-grained region. In this respect the best coarse-grained system to employ in the low resolution region would be the ideal gas, making intermolecular force calculations in the coarse-grained subdomain redundant. In this case, however, a smooth coupling is challenging due to the high energetic imbalance between typical liquids and a system of non-interacting particles. In the present work, we investigate this approach, using as a test case the most biologically relevant fluid, water. We demonstrate that a successful coupling of water to the ideal gas can be achieved with current adaptive resolution methods, and discuss the issues that remain to be addressed.
Critical behavior of the ideal-gas Bose-Einstein condensation in the Apollonian network
NASA Astrophysics Data System (ADS)
de Oliveira, I. N.; dos Santos, T. B.; de Moura, F. A. B. F.; Lyra, M. L.; Serva, M.
2013-08-01
We show that the ideal Boson gas displays a finite-temperature Bose-Einstein condensation transition in the complex Apollonian network exhibiting scale-free, small-world, and hierarchical properties. The single-particle tight-binding Hamiltonian with properly rescaled hopping amplitudes has a fractal-like energy spectrum. The energy spectrum is analytically demonstrated to be generated by a nonlinear mapping transformation. A finite-size scaling analysis over several orders of magnitudes of network sizes is shown to provide precise estimates for the exponents characterizing the condensed fraction, correlation size, and specific heat. The critical exponents, as well as the power-law behavior of the density of states at the bottom of the band, are similar to those of the ideal Boson gas in lattices with spectral dimension ds=2ln(3)/ln(9/5)?3.74.
Critical behavior of the ideal-gas Bose-Einstein condensation in the Apollonian network.
de Oliveira, I N; dos Santos, T B; de Moura, F A B F; Lyra, M L; Serva, M
2013-08-01
We show that the ideal Boson gas displays a finite-temperature Bose-Einstein condensation transition in the complex Apollonian network exhibiting scale-free, small-world, and hierarchical properties. The single-particle tight-binding Hamiltonian with properly rescaled hopping amplitudes has a fractal-like energy spectrum. The energy spectrum is analytically demonstrated to be generated by a nonlinear mapping transformation. A finite-size scaling analysis over several orders of magnitudes of network sizes is shown to provide precise estimates for the exponents characterizing the condensed fraction, correlation size, and specific heat. The critical exponents, as well as the power-law behavior of the density of states at the bottom of the band, are similar to those of the ideal Boson gas in lattices with spectral dimension d(s)=2ln(3)/ln(9/5)~/=3.74. PMID:24032807
A Quantum Gas Microscope for Ultracold Fermions
NASA Astrophysics Data System (ADS)
Nichols, Matthew; Cheuk, Lawrence; Okan, Melih; Lompe, Thomas; Zwierlein, Martin
2015-05-01
In the past decade ultracold atoms in optical lattices have been established as an ideal model system to study quantum many body physics in a clean and well-controlled environment. Recently, experiments at Harvard and MPQ Munich using bosonic 87Rb atoms have made these systems even more powerful by demonstrating the ability to observe and address atoms in optical lattices with single-site resolution. The goal of our experiment is to achieve such single-site resolution for a quantum gas of fermionic atoms. Such local probing would reveal microscopic density or spin correlations which are difficult to extract from bulk measurements. This technique could for example be used to directly observe antiferromagnetic ordering in a fermionic Mott insulator. As the starting point for our experiments we cool fermionic potassium atoms with bosonic sodium as a sympathetic coolant. The atoms are then loaded into an optical lattice located seven microns below a solid immersion microscope for high-resolution imaging. In this poster we describe how we perform single-site resolved fluorescence imaging of 40K atoms in an optical lattice with high detection fidelity.
Separation factor method for the analysis of ideal binary mixtures in gas-solid adsorption
Lee, T.V.; Huang, J.C.; Madey, R.
1984-01-01
A correlation formula based on the separation factor is proposed for the mixture concentration in the adsorbed phase of an ideal binary solution in gas-solid adsorption. This formula is shown to apply to two binary systems (viz., 1,3-butadiene and n-butane on cross-linked polystyrene at 25/sup 0/C, and acetylene and ethane on activated carbon at 25/sup 0/C) with similar molecular and thermodynamic properties in the two components for each system. Comparison between the calculated and experimental values of the separation factor showed that the assumption of an ideal mixture is justified for each of these two binary systems. Mixture isotherms for the two ideal binary systems are calculated by the proposed correlation formula from the corresponding single-component isotherms. Good agreement between the calculated and experimental mixture isotherm data confirms that a binary system of two components with similar molecular properties (viz., molecular weight, normal boiling point, vapor pressure, number of carbon atoms in molecules, etc.) tends to form an ideal mixture (i.e., one with a constant separation factor.). 24 references, 5 tables.
Equation of state of an ideal gas with nonergodic behavior in two connected vessels.
Naplekov, D M; Semynozhenko, V P; Yanovsky, V V
2014-01-01
We consider a two-dimensional collisionless ideal gas in the two vessels connected through a small hole. One of them is a well-behaved chaotic billiard, another one is known to be nonergodic. A significant part of the second vessel's phase space is occupied by an island of stability. In the works of Zaslavsky and coauthors, distribution of Poincaré recurrence times in similar systems was considered. We study the gas pressure in the vessels; it is uniform in the first vessel and not uniform in second one. An equation of the gas state in the first vessel is obtained. Despite the very different phase-space structure, behavior of the second vessel is found to be very close to the behavior of a good ergodic billiard but of different volume. The equation of state differs from the ordinary equation of ideal gas state by an amendment to the vessel's volume. Correlation of this amendment with a share of the phase space under remaining intact islands of stability is shown. PMID:24580310
Equation of state of an ideal gas with nonergodic behavior in two connected vessels
NASA Astrophysics Data System (ADS)
Naplekov, D. M.; Semynozhenko, V. P.; Yanovsky, V. V.
2014-01-01
We consider a two-dimensional collisionless ideal gas in the two vessels connected through a small hole. One of them is a well-behaved chaotic billiard, another one is known to be nonergodic. A significant part of the second vessel's phase space is occupied by an island of stability. In the works of Zaslavsky and coauthors, distribution of Poincaré recurrence times in similar systems was considered. We study the gas pressure in the vessels; it is uniform in the first vessel and not uniform in second one. An equation of the gas state in the first vessel is obtained. Despite the very different phase-space structure, behavior of the second vessel is found to be very close to the behavior of a good ergodic billiard but of different volume. The equation of state differs from the ordinary equation of ideal gas state by an amendment to the vessel's volume. Correlation of this amendment with a share of the phase space under remaining intact islands of stability is shown.
Entanglement witnessing and quantum cryptography with non-ideal ferromagnetic detectors
Waldemar K?obus; Andrzej Grudka; Andreas Baumgartner; Damian Tomaszewski; Christian Schönenberger; Jan Martinek
2014-03-05
We investigate theoretically the use of non-ideal ferromagnetic contacts as a mean to detect quantum entanglement of electron spins in transport experiments. We use a designated entanglement witness and find a minimal spin polarization of $\\eta > 1/\\sqrt{3} \\approx 58 %$ required to demonstrate spin entanglement. This is significantly less stringent than the ubiquitous tests of Bell's inequality with $\\eta > 1/\\sqrt[4]{2}\\approx 84%$. In addition, we discuss the impact of decoherence and noise on entanglement detection and apply the presented framework to a simple quantum cryptography protocol. Our results are directly applicable to a large variety of experiments.
Boal, David
PHYS 445 Lecture 6 - Classical ideal gas 6 - 1 Â© 2001 by David Boal, Simon Fraser University. All rights reserved; further resale or copying is strictly prohibited. Lecture 6 - Classical ideal gas What's Important: Â· classical phase space Text: Reif Classical ideal gas In the previous lecture, we introduced
A complete theory for the magnetism of an ideal gas of electrons
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.
Probability theory for 3-layer remote sensing in ideal gas law environment.
Ben-David, Avishai; Davidson, Charles E
2013-08-26
We extend the probability model for 3-layer radiative transfer [Opt. Express 20, 10004 (2012)] to ideal gas conditions where a correlation exists between transmission and temperature of each of the 3 layers. The effect on the probability density function for the at-sensor radiances is surprisingly small, and thus the added complexity of addressing the correlation can be avoided. The small overall effect is due to (a) small perturbations by the correlation on variance population parameters and (b) cancellation of perturbation terms that appear with opposite signs in the model moment expressions. PMID:24105525
Collision of BEC dark matter structures and comparison with the collision of ideal gas structures
Guzman, F. S.; Gonzalez, J. A.
2010-12-07
In this work we present an important feature of the Bose Einstein Condensate (BEC) dark matter model, that is, the head-on collision of BEC dark matter virialized structures. This model of dark matter is assumed to be ruled by the Schroedinger-Poisson system of equations, which is interpreted as the Gross-Pitaevskii equation with a gravitational potential sourced by the density of probability. It has been shown recently that during the collision of two structures a pattern formation in the density of probability appears. We explore the pattern formation for various initial dynamical conditions during the collision. In order to know whether or not the pattern formation is a particular property of the BEC dark matter, we compare with the collision of two structures of virialized ideal gas under similar dynamical initial conditions, which is a model more consistent with usual models of dark matter. In order to do so, we also solve Euler's equations using a smoothed particle hydrodynamics approach. We found that the collision of the ideal gas structures does not show interference patterns, which in turn implies that the pattern formation is a property of the BEC dark matter.
NASA Astrophysics Data System (ADS)
Shech, Elay
2015-09-01
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.
Ideal Negative Measurements in Quantum Walks Disprove Theories Based on Classical Trajectories
NASA Astrophysics Data System (ADS)
Robens, Carsten; Alt, Wolfgang; Meschede, Dieter; Emary, Clive; Alberti, Andrea
2015-01-01
We report on a stringent test of the nonclassicality of the motion of a massive quantum particle, which propagates on a discrete lattice. Measuring temporal correlations of the position of single atoms performing a quantum walk, we observe a 6 ? violation of the Leggett-Garg inequality. Our results rigorously excludes (i.e., falsifies) any explanation of quantum transport based on classical, well-defined trajectories. We use so-called ideal negative measurements—an essential requisite for any genuine Leggett-Garg test—to acquire information about the atom's position, yet avoiding any direct interaction with it. The interaction-free measurement is based on a novel atom transport system, which allows us to directly probe the absence rather than the presence of atoms at a chosen lattice site. Beyond the fundamental aspect of this test, we demonstrate the application of the Leggett-Garg correlation function as a witness of quantum superposition. Here, we employ the witness to discriminate different types of walks spanning from merely classical to wholly quantum dynamics.
Boyd, Robert W.
Quantum noise properties of non-ideal optical amplifiers and attenuators This article has been properties of non-ideal optical amplifiers and attenuators Zhimin Shi1 , Ksenia Dolgaleva1,2 and Robert W 26 1817) of the noise properties of ideal linear amplifiers to include the possibility of non-ideal
Compressible flow of a multiphase fluid between two vessels. Part 1: Ideal carrier gas
NASA Astrophysics Data System (ADS)
Chenoweth, Donald R.; Paolucci, Samuel
1990-06-01
The transfer of a multiphase fluid from a high pressure vessel to one initially at lower pressure is investigated. The fluid is composed of two phases which do not undergo any change. The phases consist of an ideal gas, and solid particles (or liquid droplets) having constant density. The mixture is assumed to be stagnant and always perfectly mixed as well as at thermal equilibrium in each constant volume vessel. The fluid also remains homogeneous and at equilibrium while flowing between vessels. The transport properties of the mixture are taken to be zero. One important finding is that the expanding mixture or pseudo-fluid behaves similar to a polytropic Abel-Noble gas. The mixture thermodynamic properties, the end state in each vessel at pressure equilibrium, the critical parameters, and time dependent results are given for the adiabatic and isothermal limiting cases. The results include both initially sonic and initially subsonic transfer. No mathematical restriction is placed on the particle concentration, although some limiting results are given for small particle volume fraction. The mass transferred at adiabatic pressure equilibrium can be significantly less than that when thermal equilibrium is also reached. Furthermore, the adiabatic pressure equilibrium level may not be the same as that obtained at thermal equilibrium, even when all initial temperatures are the same. Finally, it is shown that the transfer times can be very slow compared to those of a pure gas due to the large reduction possible in the mixture sound speed.
Generic features of the wealth distribution in ideal-gas-like markets
NASA Astrophysics Data System (ADS)
Mohanty, P. K.
2006-07-01
We provide an exact solution to the ideal-gas-like models studied in econophysics to understand the microscopic origin of Pareto law. In these classes of models the key ingredient necessary for having a self-organized scale-free steady-state distribution is the trading or collision rule where agents or particles save a definite fraction of their wealth or energy and invest the rest for trading. Using a Gibbs ensemble approach we could obtain the exact distribution of wealth in this model. Moreover we show that in this model (a) good savers are always rich and (b) every agent poor or rich invests the same amount for trading. Nonlinear trading rules could alter the generic scenario observed here.
Real-time dynamics of an impurity in an ideal Bose gas in a trap
NASA Astrophysics Data System (ADS)
Volosniev, A. G.; Hammer, H.-W.; Zinner, N. T.
2015-08-01
We investigate the behavior of a harmonically trapped system consisting of an impurity in a dilute ideal Bose gas after the boson-impurity interaction is suddenly switched on. As a theoretical framework, we use a field-theory approach in the space-time domain within the T -matrix approximation. We establish the form of the corresponding T matrix and address the dynamical properties of the system. As a numerical application, we consider a simple system of a weakly interacting impurity in one dimension where the interaction leads to oscillations of the impurity density. Moreover, we show that the amplitude of the oscillations can be driven by periodically switching the interaction on and off.
Generic features of the wealth distribution in ideal-gas-like markets
P. K. Mohanty
2006-07-10
We provide an exact solution to the ideal-gas-like models studied in econophysics to understand the microscopic origin of Pareto-law. In these class of models the key ingredient necessary for having a self-organized scale-free steady-state distribution is the trading or collision rule where agents or particles save a definite fraction of their wealth or energy and invests the rest for trading. Using a Gibbs ensemble approach we could obtain the exact distribution of wealth in this model. Moreover we show that in this model (a) good savers are always rich and (b) every agent poor or rich invests the same amount for trading. Nonlinear trading rules could alter the generic scenario observed here.
Fielitz, P
2009-01-01
We consider a general information transfer model which comprises any natural process which is able to transfer information and which can be characterised by only two independent process variables. We further postulate that these independent process variables serve as source and destination of information during a natural process. To define information which is directly related to the process variables, we apply the definition of information originally formulated by Hartley. We demonstrate that the proposed information transfer model yields well known laws, which, as yet, have not been directly related to information theory, such as the ideal gas law, the radioactive decay law, the formation law of vacancies in single crystals, and Fick's first law. Further, for the propagation of photons from a point source the information transfer model shows that any detector device, if at rest relative to the point source, will measure a redshift relative to the photon wavelength which is emitted from the point source. Tha...
Heat-flow equation motivated by the ideal-gas shock wave.
Holian, Brad Lee; Mareschal, Michel
2010-08-01
We present an equation for the heat-flux vector that goes beyond Fourier's Law of heat conduction, in order to model shockwave propagation in gases. Our approach is motivated by the observation of a disequilibrium among the three components of temperature, namely, the difference between the temperature component in the direction of a planar shock wave, versus those in the transverse directions. This difference is most prominent near the shock front. We test our heat-flow equation for the case of strong shock waves in the ideal gas, which has been studied in the past and compared to Navier-Stokes solutions. The new heat-flow treatment improves the agreement with nonequilibrium molecular-dynamics simulations of hard spheres under strong shockwave conditions. PMID:20866940
Generic features of the wealth distribution in ideal-gas-like markets.
Mohanty, P K
2006-07-01
We provide an exact solution to the ideal-gas-like models studied in econophysics to understand the microscopic origin of Pareto law. In these classes of models the key ingredient necessary for having a self-organized scale-free steady-state distribution is the trading or collision rule where agents or particles save a definite fraction of their wealth or energy and invest the rest for trading. Using a Gibbs ensemble approach we could obtain the exact distribution of wealth in this model. Moreover we show that in this model (a) good savers are always rich and (b) every agent poor or rich invests the same amount for trading. Nonlinear trading rules could alter the generic scenario observed here. PMID:16907070
Real-Time Dynamics of an Impurity in an Ideal Bose Gas in a Trap
Volosniev, A G; Zinner, N T
2015-01-01
We investigate the behavior of a harmonically trapped system consisting of an impurity in a dilute ideal Bose gas after the boson-impurity interaction is suddenly switched on. As theoretical framework, we use a field theory approach in the space-time domain within the T-matrix approximation. We establish the form of the corresponding T-matrix and address the dynamical properties of the system. As a numerical application, we consider a simple system of a weakly interacting impurity in one dimension where the interaction leads to oscillations of the impurity density. Moreover, we show that the amplitude of the oscillations can be driven by periodically switching the interaction on and off.
Non-ideal effects in organic inorganic materials for gas separation membranes
NASA Astrophysics Data System (ADS)
Moore, Theodore T.; Koros, William J.
2005-04-01
Organic-inorganic hybrids, so-called 'mixed matrix', materials comprising highly selective rigid phases, such as zeolites, dispersed in a continuous polymeric matrix are leading candidates for challenging membrane applications. In addition to ideal additive effects modeled in terms of the intrinsic properties of the continuous and dispersed phases, the dispersed phase may affect the surrounding polymer matrix at the interface between the two phases. For instance, the dispersed phase may cause an undesirable void at the interface or create varying degrees of rigidification in the surrounding polymer. The observed performance as a gas separation material depends strongly upon the specific preparation conditions. The properties of the interface may, therefore, be understood better by considering gas permeation and sorption experiments, coupled with appropriate modeling. For a given polymer and dispersed phase, the stress at the interface during membrane preparation is believed to determine whether a void or a rigidified region of polymer forms at the interface and to what extent. This stress depends primarily on the amount of solvent left to be removed when the nascent polymer matrix vitrifies. The response to preparation-generated stresses can also be affected by chemical 'priming', for example using silane or other coupling agents. Here, we discuss how solvent evaporation, thermal effects, and the resulting stresses at the polymer-dispersed phase interface cause a complex, but at least partially understood array of effects ranging from void formation to stress-dilated regions or even zones of compression in the polymer layers nearest the polymer-dispersed phase interface. Other non-ideal effects can be due to partial or apparent clogging of the dispersed phase. In fact, depending on particle size, shape and preparation protocols, two or more of these effects may superimpose to create a rich array of properties beyond those described by simple models based on only pure material properties. Using this framework, preparation conditions to tailor the interfacial morphology and therefore, membrane transport properties are discussed.
Slippage and boundary layer probed in an almost ideal gas by a nanomechanical oscillator.
Defoort, M; Lulla, K J; Crozes, T; Maillet, O; Bourgeois, O; Collin, E
2014-09-26
We measure the interaction between ?He gas at 4.2 K and a high-quality nanoelectromechanical string device for its first three symmetric modes (resonating at 2.2, 6.7, and 11 MHz with quality factor Q>0.1×10?) over almost 6 orders of magnitude in pressure. This fluid can be viewed as the best experimental implementation of an almost ideal monoatomic and inert gas of which properties are tabulated. The experiment ranges from high pressure where the flow is of laminar Stokes-type presenting slippage down to very low pressures where the flow is molecular. In the molecular regime, when the mean-free path is of the order of the distance between the suspended nanomechanical probe and the bottom of the trench, we resolve for the first time the signature of the boundary (Knudsen) layer onto the measured dissipation. Our results are discussed in the framework of the most recent theories investigating boundary effects in fluids (both analytic approaches and direct simulation Monte Carlo methods). PMID:25302905
Analytical theory of mesoscopic Bose-Einstein condensation in an ideal gas
Kocharovsky, Vitaly V.; Kocharovsky, Vladimir V.
2010-03-15
We find the universal structure and scaling of the Bose-Einstein condensation (BEC) statistics and thermodynamics (Gibbs free energy, average energy, heat capacity) for a mesoscopic canonical-ensemble ideal gas in a trap with an arbitrary number of atoms, any volume, and any temperature, including the whole critical region. We identify a universal constraint-cutoff mechanism that makes BEC fluctuations strongly non-Gaussian and is responsible for all unusual critical phenomena of the BEC phase transition in the ideal gas. The main result is an analytical solution to the problem of critical phenomena. It is derived by, first, calculating analytically the universal probability distribution of the noncondensate occupation, or a Landau function, and then using it for the analytical calculation of the universal functions for the particular physical quantities via the exact formulas which express the constraint-cutoff mechanism. We find asymptotics of that analytical solution as well as its simple analytical approximations which describe the universal structure of the critical region in terms of the parabolic cylinder or confluent hypergeometric functions. The obtained results for the order parameter, all higher-order moments of BEC fluctuations, and thermodynamic quantities perfectly match the known asymptotics outside the critical region for both low and high temperature limits. We suggest two- and three-level trap models of BEC and find their exact solutions in terms of the cutoff negative binomial distribution (which tends to the cutoff gamma distribution in the continuous limit) and the confluent hypergeometric distribution, respectively. Also, we present an exactly solvable cutoff Gaussian model of BEC in a degenerate interacting gas. All these exact solutions confirm the universality and constraint-cutoff origin of the strongly non-Gaussian BEC statistics. We introduce a regular refinement scheme for the condensate statistics approximations on the basis of the infrared universality of higher-order cumulants and the method of superposition and show how to model BEC statistics in the actual traps. In particular, we find that the three-level trap model with matching the first four or five cumulants is enough to yield remarkably accurate results for all interesting quantities in the whole critical region. We derive an exact multinomial expansion for the noncondensate occupation probability distribution and find its high-temperature asymptotics (Poisson distribution) and corrections to it. Finally, we demonstrate that the critical exponents and a few known terms of the Taylor expansion of the universal functions, which were calculated previously from fitting the finite-size simulations within the phenomenological renormalization-group theory, can be easily obtained from the presented full analytical solutions for the mesoscopic BEC as certain approximations in the close vicinity of the critical point.
Quantum characteristics of occurrence scattering time in two-component non-ideal plasmas
NASA Astrophysics Data System (ADS)
Hong, Woo-Pyo; Jung, Young-Dae
2015-10-01
The quantum diffraction and plasma screening effects on the occurrence time for the collision process are investigated in two-component non-ideal plasmas. The micropotential model taking into account the quantum diffraction and screening with the eikonal analysis is employed to derive the occurrence time as functions of the collision energy, density parameter, Debye length, de Broglie wavelength, and scattering angle. It is shown that the occurrence time for forward scattering directions decreases the tendency of time-advance with increasing scattering angle and de Broglie wavelength. However, it is found that the occurrence time shows the oscillatory time-advance and time-retarded behaviors with increasing scattering angle. It is found that the plasma screening effect enhances the tendency of time-advance on the occurrence time for forward scattering regions. It is also shown the quantum diffraction effect suppresses the occurrence time advance for forward scattering angles. In addition, it is shown that the occurrence time advance decreases with an increase of the collision energy.
TP A SOLUTION For an ideal monatomic gas U=3/2nRT , RCV 2/3= and RRRCP 2/52/3 =+= .
Gustafsson, Torgny
kT . Then, if n is eliminated using the ideal gas law (P = nkT), one can solve for the chemical with the ideal gas law. #12;TP C2 SOLUTION (a) ( ) 23 210 26 2 /1046.9 108.54 104 4 mW m W R P J orbit SunTP A SOLUTION For an ideal monatomic gas U=3/2nRT , RCV 2/3= and RRRCP 2/52/3 =+= . Since
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…
The ideal relativistic rotating gas as a perfect fluid with spin
Becattini, F.; Tinti, L.
2010-08-15
We show that the ideal relativistic spinning gas at complete thermodynamical equilibrium is a fluid with a non-vanishing spin density tensor {sigma}{sub {mu}{nu}}. After having obtained the expression of the local spin-dependent phase-space density f(x, p){sub {sigma}{tau}} in the Boltzmann approximation, we derive the spin density tensor and show that it is proportional to the acceleration tensor {Omega}{sub {mu}{nu}} constructed with the Frenet-Serret tetrad. We recover the proper generalization of the fundamental thermodynamical relation, involving an additional term -(1/2){Omega}{sub {mu}{nu}{sigma}}{sup {mu}{nu}}. We also show that the spin density tensor has a non-vanishing projection onto the four-velocity field, i.e. t{sup {mu}} = {sigma}{sub {mu}}{nu}u{sup {nu}} {ne} 0, in contrast to the common assumption t{sup {mu}} = 0, known as Frenkel condition, in the thus-far proposed theories of relativistic fluids with spin. We briefly address the viewpoint of the accelerated observer and inertial spin effects.
Determination of ideal-gas enthalpies of formation for key compounds:
Steele, W.V.; Chirico, R.D.; Nguyen, A.; Hossenlopp, I.A.; Smith, N.K.
1991-10-01
The results of a study aimed at improvement of group-contribution methodology for estimation of thermodynamic properties of organic and organosilicon 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 the condensed phase, vapor-pressure measurements, and differential scanning calorimetric (d.s.c.) heat-capacity measurements. Ideal-gas enthalpies of formation of ({plus minus})-butan-2-ol, tetradecan-1-ol, hexan-1,6-diol, methacrylamide, benzoyl formic acid, naphthalene-2,6-dicarboxylic acid dimethyl ester, and tetraethylsilane are reported. A crystalline-phase enthalpy of formation at 298.15 K was determined for naphthalene-2,6-dicarboxylic acid, which decomposed at 695 K before melting. The combustion calorimetry of tetraethylsilane used the proven fluorine-additivity methodology. Critical temperature and critical density were determined for tetraethylsilane with differential scanning calorimeter and the critical pressure was derived. Group-additivity parameters useful in the application of group- contribution correlations are derived. 112 refs., 13 figs., 19 tabs.
Quantum learning for a quantum lattice gas computer
NASA Astrophysics Data System (ADS)
Behrman, Elizabeth; Steck, James
2015-03-01
Quantum lattice gas is the logical generalization of quantum cellular automata. In low energy the dynamics are well described by the Gross-Pitaevskii equation in the mean field limit, which is an effective nonlinear interaction model of a Bose-Einstein condensate. In previous work, we have shown in simulation that both spatial and temporal models of quantum learning computers can be used to ``design'' non-trivial quantum algorithms. The advantages of quantum learning over the usual practice of using quantum gate building blocks are, first, the rapidity with which the problem can be solved, without having to decompose the problem; second, the fact that our technique can be used readily even when the problem, or the operator, is not well understood; and, third, that because the interactions are a natural part of the physical system, connectivity is automatic. The advantage to quantum learning obviously grows with the size and the complexity of the problem. We develop and present our learning algorithm as applied to the mean field lattice gas equation, and present a few preliminary results.
Quantum learning in a quantum lattice gas computer
NASA Astrophysics Data System (ADS)
Behrman, Elizabeth; Steck, James
2015-04-01
Quantum lattice gas is the logical generalization of quantum cellular automata. At low energy the dynamics are well described by the Gross-Pitaevskii equation in the mean field limit, which is an effective nonlinear interaction model of a Bose-Einstein condensate. In previous work, we have shown in simulation that both spatial and temporal models of quantum learning computers can be used to ``design'' non-trivial quantum algorithms. The advantages of quantum learning over the usual practice of using quantum gate building blocks are, first, the rapidity with which the problem can be solved, without having to decompose the problem; second, the fact that our technique can be used readily even when the problem, or the operator, is not well understood; and, third, that because the interactions are a natural part of the physical system, connectivity is automatic. The advantage to quantum learning obviously grows with the size and the complexity of the problem. We develop and present our learning algorithm as applied to the mean field lattice gas equation, and present a few preliminary results.
Risto Leinonen; Mervi A. Asikainen; Pekka E. Hirvonen
This study focuses on second-year university students’ explanations and reasoning related to adiabatic compression of an ideal\\u000a gas. The phenomenon was new to the students, but it was one which they should have been capable of explaining using their\\u000a previous upper secondary school knowledge. The students’ explanations and reasoning were investigated with the aid of paper\\u000a and pencil tests (n?=?86)
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).
History dependent quantum random walks as quantum lattice gas automata
NASA Astrophysics Data System (ADS)
Shakeel, Asif; Meyer, David A.; Love, Peter J.
2014-12-01
Quantum Random Walks (QRW) were first defined as one-particle sectors of Quantum Lattice Gas Automata (QLGA). Recently, they have been generalized to include history dependence, either on previous coin (internal, i.e., spin or velocity) states or on previous position states. These models have the goal of studying the transition to classicality, or more generally, changes in the performance of quantum walks in algorithmic applications. We show that several history dependent QRW can be identified as one-particle sectors of QLGA. This provides a unifying conceptual framework for these models in which the extra degrees of freedom required to store the history information arise naturally as geometrical degrees of freedom on the lattice.
Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles
Sašo Grozdanov; Janos Polonyi
2015-01-26
We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, composite sound waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition between the hydrodynamical regime of an ideal gas, defined in this work, and the hydrodynamical regime in phenomenological hydrodynamics, which is normally used for the description of interacting gases.
Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles
Sašo Grozdanov; Janos Polonyi
2015-09-03
We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, {\\it composite sound} waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition between the hydrodynamical regime of an ideal gas, defined in this work, and the hydrodynamical regime in phenomenological hydrodynamics, which is normally used for the description of interacting gases.
On the Equipartition of Kinetic Energy in an Ideal Gas Mixture
ERIC Educational Resources Information Center
Peliti, L.
2007-01-01
A refinement of an argument due to Maxwell for the equipartition of translational kinetic energy in a mixture of ideal gases with different masses is proposed. The argument is elementary, yet it may work as an illustration of the role of symmetry and independence postulates in kinetic theory. (Contains 1 figure.)
Mesoscopic Effects in Bose-Einstein Condensate Fluctuations of an Ideal Gas in a Box
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...
Towards a Quantum Gas Microscope for Ultracold Fermions
NASA Astrophysics Data System (ADS)
Nichols, Matthew; Cheuk, Lawrence; Okan, Melih; Ramasesh, Vinay; Bakr, Waseem; Lompe, Thomas; Zwierlein, Martin
2014-05-01
In the past decade ultracold atoms in optical lattices have been established as an ideal model system to study quantum many body physics in a clean and well-controlled environment. Recently, experiments at Harvard and MPQ Munich using bosonic 87Rb atoms have made these systems even more powerful by demonstrating the ability to observe and address atoms in optical lattices with single-site resolution. The goal of our experiment is to achieve such single-site resolution for a quantum gas of fermionic atoms. Such local probing would reveal microscopic density or spin correlations which are difficult to extract from bulk measurements. This technique could for example be used to directly observe antiferromagnetic ordering in a fermionic Mott insulator. As the starting point for our experiments we cool fermionic potassium atoms with bosonic sodium as a sympathetic coolant. The atoms are then magnetically transported to an optical trap located ten microns below a solid immersion microscope for high-resolution imaging. In this poster we give a description of our experimental setup and report on our progress towards performing single-site resolved fluorescence imaging of 40K atoms trapped in a deep optical lattice. Currently at University of California, Berkeley.
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.
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.
The Heat Capacity of Ideal Gases
ERIC Educational Resources Information Center
Scott, Robert L.
2006-01-01
The heat capacity of an ideal gas has been shown to be calculable directly by statistical mechanics if the energies of the quantum states are known. However, unless one makes careful calculations, it is not easy for a student to understand the qualitative results. Why there are maxima (and occasionally minima) in heat capacity-temperature curves…
NASA Technical Reports Server (NTRS)
Hall, R. M.; Adcock, J. B.
1981-01-01
The real gas behavior of nitrogen, the gas normally used in transonic cryogenic tunnels, is reported for the following flow processes: isentropic expansion, normal shocks, boundary layers, and interactions between shock waves and boundary layers. The only difference in predicted pressure ratio between nitrogen and an ideal gas which may limit the minimum operating temperature of transonic cryogenic wind tunnels occur at total pressures approaching 9 atm and total temperatures 10 K below the corresponding saturation temperature. These pressure differences approach 1 percent for both isentropic expansions and normal shocks. Alternative cryogenic test gases were also analyzed. Differences between air and an ideal diatomic gas are similar in magnitude to those for nitrogen and should present no difficulty. However, differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. It is concluded that helium and cryogenic hydrogen would not approximate the compressible flow of an ideal diatomic gas.
Appalachian independent producers approach to marketing gas: Idealism vs. reality - a case study
Linn, M.C.
1988-08-01
The new marketplace dictates lower prices through the development of new marketing techniques and transportation policies. This environment has created a new means of doing business through the spot market. It has become routine for an end user to purchase a 30-day supply of gas from a Gulf Coast producer and enter into transportation contracts with interstate pipelines and his local utility company, thereby saving considerable sums of money at the burner tip. The end user knows that natural gas has become an openly traded commodity in a highly competitive marketplace. The Appalachian basin producer must operate within this environment by pursuing industrial end-user markets. The authors can successfully execute contracts and deliver their gas to small industries that are willing to pay a slightly higher price in order to have a reliable supply. The producer may even choose to blend his gas with other sources to provide a more competitive burner-tip price. Meridian Exploration Corporation is recognized as being a pioneer in direct gas sales. The company serves as operator for over 850 natural gas and associated oil wells located principally in Pennsylvanian and New York. Meridian is moving nearly 80% of its daily gas output to numerous end users. Meridian counts among its customers large volume industries, colleges and universities, apartment complexes, shopping centers, and greenhouses.
Quantum lattice-gas model for computational fluid dynamics.
Yepez, J
2001-04-01
Quantum-computing ideas are applied to the practical and ubiquitous problem of fluid dynamics simulation. Hence, this paper addresses two separate areas of physics: quantum mechanics and fluid dynamics (or specifically, the computational simulation of fluid dynamics). The quantum algorithm is called a quantum lattice gas. An analytical treatment of the microscopic quantum lattice-gas system is carried out to predict its behavior at the mesoscopic scale. At the mesoscopic scale, a lattice Boltzmann equation with a nonlocal collision term that depends on the entire system wave function, governs the dynamical system. Numerical results obtained from an exact simulation of a one-dimensional quantum lattice model are included to illustrate the formalism. A symbolic mathematical method is used to implement the quantum mechanical model on a conventional workstation. The numerical simulation indicates that classical viscous damping is not present in the one-dimensional quantum lattice-gas system. PMID:11308976
NASA Astrophysics Data System (ADS)
Leinonen, Risto; Asikainen, Mervi A.; Hirvonen, Pekka E.
2012-12-01
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 investigated with the aid of paper and pencil tests ( n = 86) and semi-structured interviews ( n = 5) at the start of a thermal physics course at the University of Eastern Finland. The paper and pencil test revealed that the students had difficulties in applying content taught during earlier education in a new context: only a few of them were able to produce a correct explanation for the phenomenon. A majority of the students used either explanations with invalid but physically correct models, such as the ideal gas law or a microscopic model, or erroneous dependencies between quantities. The results also indicated that students had problems in seeing deficiencies or inconsistencies in their reasoning, in both test and interview situations. We suggest in our conclusion that the contents of upper secondary school thermal physics courses should be carefully examined to locate the best emphases for different laws, principles, concepts, and models. In particular, the limitations of models should be made explicit in teaching and students should be guided towards critical scientific thinking, including metaconceptual awareness.
Bose-Einstein condensation of photons in an ideal atomic gas
NASA Astrophysics Data System (ADS)
Kruchkov, Alex; Slyusarenko, Yurii
2013-07-01
We study peculiarities of Bose-Einstein condensation of photons that are in thermodynamic equilibrium with atoms of noninteracting gases. General equations of the thermodynamic equilibrium of the system under study are obtained. We examine solutions of these equations in the case of high temperatures, when the atomic components of the system can be considered as nondegenerated ideal gases of atoms, and the photonic component can form a state with the Bose condensate. Transcendental equation for transition temperature and expression for the density of condensed photons in the considered system are derived. We also obtain analytical solutions of the equation for the critical temperature in a number of particular cases. The existence of two regimes of Bose condensation of photons, which differ significantly in nature of transition temperature dependence on the total density of photons pumped into the system, is revealed. In one case, this dependence is a traditional fractional-power law, and in another one it is the logarithmic law. Applying numerical methods, we determine boundaries of existence and implementation conditions for different regimes of condensation depending on the physical parameters of the system under study. We also show that for a large range of physical systems that are in equilibrium with photons (from ultracold gases of alkali metals to certain types of ideal plasma), the condensation of photons should occur according to the logarithmic regime.
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.
Quantum-gas microscope for fermionic atoms.
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
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.
Idealized gas turbine combustor for performance research and validation of large eddy simulations.
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. PMID:17411224
Condensation of ideal Bose gas confined in a box within a canonical ensemble
Glaum, Konstantin; Kleinert, Hagen; Pelster, Axel [Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, 14195 Berlin (Germany); Fachbereich Physik, Universitaet Duisburg-Essen, Campus Duisburg, Lotharstrasse 1, 47048 Duisburg (Germany)
2007-12-15
We set up recursion relations for the partition function and the ground-state occupancy for a fixed number of noninteracting bosons confined in a square box potential and determine the temperature dependence of the specific heat and the particle number in the ground state. A proper semiclassical treatment is set up which yields the correct small-T behavior in contrast to an earlier theory in Feynman's textbook on statistical mechanics, in which the special role of the ground state was ignored. The results are compared with an exact quantum-mechanical treatment. Furthermore, we derive the finite-size effect of the system.
Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles
Grozdanov, Sašo
2015-01-01
We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, composite sound waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition betwee...
NASA Technical Reports Server (NTRS)
Lee, Jeffrey M.
1999-01-01
This study establishes a consistent set of differential equations for use in describing the steady secondary flows generated by periodic compression and expansion of an ideal gas in pulse tubes. Also considered is heat transfer between the gas and the tube wall of finite thickness. A small-amplitude series expansion solution in the inverse Strouhal number is proposed for the two-dimensional axisymmetric mass, momentum and energy equations. The anelastic approach applies when shock and acoustic energies are small compared with the energy needed to compress and expand the gas. An analytic solution to the ordered series is obtained in the strong temperature limit where the zeroth-order temperature is constant. The solution shows steady velocities increase linearly for small Valensi number and can be of order I for large Valensi number. A conversion of steady work flow to heat flow occurs whenever temperature, velocity or phase angle gradients are present. Steady enthalpy flow is reduced by heat transfer and is scaled by the Prandtl times Valensi numbers. Particle velocities from a smoke-wire experiment were compared with predictions for the basic and orifice pulse tube configurations. The theory accurately predicted the observed steady streaming.
Ideal gas in a strong gravitational field: Area dependence of entropy
Kolekar, Sanved; Padmanabhan, T. [IUCAA, Pune University Campus, Ganeshkhind, Pune 411007 (India)
2011-03-15
We study the thermodynamic parameters like entropy, energy etc. of a box of gas made up of indistinguishable particles when the box is kept in various static background spacetimes having a horizon. We compute the thermodynamic variables using both statistical mechanics as well as by solving the hydrodynamical equations for the system. When the box is far away from the horizon, the entropy of the gas depends on the volume of the box except for small corrections due to background geometry. As the box is moved closer to the horizon with one (leading) edge of the box at about Planck length (L{sub p}) away from the horizon, the entropy shows an area dependence rather than a volume dependence. More precisely, it depends on a small volume A{sub perpendicular}L{sub p}/2 of the box, up to an order O(L{sub p}/K){sup 2} where A{sub perpendicular} is the transverse area of the box and K is the (proper) longitudinal size of the box related to the distance between leading and trailing edge in the vertical direction (i.e. in the direction of the gravitational field). Thus the contribution to the entropy comes from only a fraction O(L{sub p}/K) of the matter degrees of freedom and the rest are suppressed when the box approaches the horizon. Near the horizon all the thermodynamical quantities behave as though the box of gas has a volume A{sub perpendicular}L{sub p}/2 and is kept in a Minkowski spacetime. These effects are: (i) purely kinematic in their origin and are independent of the spacetime curvature (in the sense that the Rindler approximation of the metric near the horizon can reproduce the results) and (ii) observer dependent. When the equilibrium temperature of the gas is taken to be equal to the horizon temperature, we get the familiar A{sub perpendicular}/L{sub p}{sup 2} dependence in the expression for entropy. All these results hold in a D+1 dimensional spherically symmetric spacetime. The analysis based on methods of statistical mechanics and the one based on thermodynamics applied to the gas treated as a fluid in static geometry, lead to the same results showing the consistency. The implications are discussed.
Thermodynamics and kinetics of binary nucleation in ideal-gas mixtures
NASA Astrophysics Data System (ADS)
Alekseechkin, Nikolay V.
2015-08-01
The nonisothermal single-component theory of droplet nucleation [N. V. Alekseechkin, Physica A 412, 186 (2014)] is extended to binary case; the droplet volume V, composition x, and temperature T are the variables of the theory. An approach based on macroscopic kinetics (in contrast to the standard microscopic model of nucleation operating with the probabilities of monomer attachment and detachment) is developed for the droplet evolution and results in the derived droplet motion equations in the space (V, x, T)—equations for V ? ? d V / d t , x ? , and T ? . The work W(V, x, T) of the droplet formation is obtained in the vicinity of the saddle point as a quadratic form with diagonal matrix. Also, the problem of generalizing the single-component Kelvin equation for the equilibrium vapor pressure to binary case is solved; it is presented here as a problem of integrability of a Pfaffian equation. The equation for T ? is shown to be the first law of thermodynamics for the droplet, which is a consequence of Onsager's reciprocal relations and the linked-fluxes concept. As an example of ideal solution for demonstrative numerical calculations, the o-xylene-m-xylene system is employed. Both nonisothermal and enrichment effects are shown to exist; the mean steady-state overheat of droplets and their mean steady-state enrichment are calculated with the help of the 3D distribution function. Some qualitative peculiarities of the nucleation thermodynamics and kinetics in the water-sulfuric acid system are considered in the model of regular solution. It is shown that there is a small kinetic parameter in the theory due to the small amount of the acid in the vapor and, as a consequence, the nucleation process is isothermal.
Thermodynamics and kinetics of binary nucleation in ideal-gas mixtures.
Alekseechkin, Nikolay V
2015-08-01
The nonisothermal single-component theory of droplet nucleation [N. V. Alekseechkin, Physica A 412, 186 (2014)] is extended to binary case; the droplet volume V, composition x, and temperature T are the variables of the theory. An approach based on macroscopic kinetics (in contrast to the standard microscopic model of nucleation operating with the probabilities of monomer attachment and detachment) is developed for the droplet evolution and results in the derived droplet motion equations in the space (V, x, T)-equations for V??dV/dt, ?, and ?. The work W(V, x, T) of the droplet formation is obtained in the vicinity of the saddle point as a quadratic form with diagonal matrix. Also, the problem of generalizing the single-component Kelvin equation for the equilibrium vapor pressure to binary case is solved; it is presented here as a problem of integrability of a Pfaffian equation. The equation for ? is shown to be the first law of thermodynamics for the droplet, which is a consequence of Onsager's reciprocal relations and the linked-fluxes concept. As an example of ideal solution for demonstrative numerical calculations, the o-xylene-m-xylene system is employed. Both nonisothermal and enrichment effects are shown to exist; the mean steady-state overheat of droplets and their mean steady-state enrichment are calculated with the help of the 3D distribution function. Some qualitative peculiarities of the nucleation thermodynamics and kinetics in the water-sulfuric acid system are considered in the model of regular solution. It is shown that there is a small kinetic parameter in the theory due to the small amount of the acid in the vapor and, as a consequence, the nucleation process is isothermal. PMID:26254656
Ideal-Modified Bosonic Gas Trapped in an Arbitrary Three Dimensional Power-Law Potential
E. Castellanos; C. Laemmerzahl
2012-10-22
We analyze the effects caused by an anomalous single-particle dispersion relation suggested in several quantum-gravity models, upon the thermodynamics of a Bose-Einstein condensate trapped in a generic 3-dimensional power-law potential. We prove that the shift in the condensation temperature, caused by a deformed dispersion relation, described as a non-trivial function of the number of particles and the shape associated to the corresponding trap, could provide bounds for the parameters associated to such deformation. Additionally, we calculate the fluctuations in the number of particles as a criterium of thermodynamic stability for these systems. We show that the apparent instability caused by the anomalous fluctuations in the thermodynamic limit can be suppressed considering the lowest energy associated to the system in question.
Beau, Mathieu, E-mail: mbeau@stp.dias.ie [Dublin Institute for Advanced Studies School of Theoretical Physics, 10 Burlington Road, Dublin 4 (Ireland)] [Dublin Institute for Advanced Studies School of Theoretical Physics, 10 Burlington Road, Dublin 4 (Ireland); Savoie, Baptiste, E-mail: baptiste.savoie@gmail.com [Department of Mathematical Sciences, University of Aarhus, Ny Munkegade, Building 1530, DK-8000 Aarhus C (Denmark)] [Department of Mathematical Sciences, University of Aarhus, Ny Munkegade, Building 1530, DK-8000 Aarhus C (Denmark)
2014-05-15
In this paper, we rigorously investigate the reduced density matrix (RDM) associated to the ideal Bose gas in harmonic traps. We present a method based on a sum-decomposition of the RDM allowing to treat not only the isotropic trap, but also general anisotropic traps. When focusing on the isotropic trap, the method is analogous to the loop-gas approach developed by Mullin [“The loop-gas approach to Bose-Einstein condensation for trapped particles,” Am. J. Phys. 68(2), 120 (2000)]. Turning to the case of anisotropic traps, we examine the RDM for some anisotropic trap models corresponding to some quasi-1D and quasi-2D regimes. For such models, we bring out an additional contribution in the local density of particles which arises from the mesoscopic loops. The close connection with the occurrence of generalized-Bose-Einstein condensation is discussed. Our loop-gas-like approach provides relevant information which can help guide numerical investigations on highly anisotropic systems based on the Path Integral Monte Carlo method.
Ideal Stabilization 197 Ideal Stabilization
Nesterenko, Mikhail
Ideal Stabilization 197 Ideal Stabilization Mikhail Nesterenko Kent State University, USA S and reasoning about forward recovery fault tolerant programs. We call it ideal stabilization. The program is ideally stabilizing if its every state is legitimate. Ideal stabilization allows the specification
Quantum Joule-Thomson effect in a saturated homogeneous Bose gas.
Schmidutz, Tobias F; Gotlibovych, Igor; Gaunt, Alexander L; Smith, Robert P; Navon, Nir; Hadzibabic, Zoran
2014-01-31
We study the thermodynamics of Bose-Einstein condensation in a weakly interacting quasihomogeneous atomic gas, prepared in an optical-box trap. We characterize the critical point for condensation and observe saturation of the thermal component in a partially condensed cloud, in agreement with Einstein's textbook picture of a purely statistical phase transition. Finally, we observe the quantum Joule-Thomson effect, namely isoenthalpic cooling of an (essentially) ideal gas. In our experiments this cooling occurs spontaneously, due to energy-independent collisions with the background gas in the vacuum chamber. We extract a Joule-Thomson coefficient ?JT>10(9)??K/bar, about 10 orders of magnitude larger than observed in classical gases. PMID:24580421
Quantum noise of non-ideal Sagnac speed meter interferometer with asymmetries
NASA Astrophysics Data System (ADS)
Danilishin, S. L.; Gräf, C.; Leavey, S. S.; Hennig, J.; Houston, E. A.; Pascucci, D.; Steinlechner, S.; Wright, J.; Hild, S.
2015-04-01
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 generalized, 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 to illustrate how our findings affect Sagnac speed meters with metre- and kilometre-long baselines.
Large deviations for ideal quantum Joel L. Lebowitz 1;2; \\Lambda Marco Lenci 1;y
08854, U.S.A. 3 Zentrum Mathematik and Physik Department Technische UniversitÂ¨at 80290 MÂ¨unchen, GermanyÂdimensional quantum system of nonÂinterÂ acting particles, with suitable statistics, in a very large (formally infi Statistical mechanics is the bridge between the microscopic world of atoms and the macroscopic world of bulk
Quantum noise of non-ideal Sagnac speed meter interferometer with asymmetries
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.
Jack polynomials as fractional quantum Hall states and the Betti numbers of the (k+1)-equals ideal
Christine Berkesch Zamaere; Stephen Griffeth; Steven V Sam
2014-04-23
We show that for Jack parameter \\alpha = -(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 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 2k+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.
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…
Approaching the ideal quantum key distribution with two-intensity decoy states
NASA Astrophysics Data System (ADS)
Zhang, Chun-Hui; Luo, Sun-Long; Guo, Guang-Can; Wang, Qin
2015-08-01
We present a scheme for the practical decoy-state quantum key distribution with heralded single-photon source. In this scheme, only two-intensity decoy states are employed. However, its performance can approach the asymptotic case of using infinite decoy states. We compare it with the standard three-intensity decoy-state method, and through numerical simulations, we demonstrate its significant improvement over the three-intensity method in both the final key rate and the secure transmission distance. Furthermore, when taking statistical fluctuations into account, a very high key generation rate can still be obtained even at a long transmission distance.
NASA Astrophysics Data System (ADS)
Krayko, A. N.; Tillyayeva, N. I.; Shcherbakov, S. A.
1987-06-01
A method of calculations for flow of an ideal gas through nozzles is outlined which combines the Godunov-Kolgan modification of the Godunov scheme with the method of characteristics, using analytical solutions at the nozzle axis and at an acoustic saliency. Monotonicity of the original Godunov scheme is retained, owing to a procedure for determining large quantities on both sides of the grid boundary. This combination method is applicable to any arbitrary two-dimensional or three-dimensional grid. Its efficiency and precision are demonstrated on irregular grids for nozzles with broken-line contours. As a test case, a nozzle contour is selected with a supersonic saliency, but resorting to the method of characteristics facilitates calculations for transonic and subsonic flow as well without restrictions on the degree of contour smoothness. Analytical solutions yield the inclination angle of the velocity vector on an acoustic line as a function of one coordinate so that the other coordinate can be found and the acoustic line can be plotted in the plane of flow. The method has been programmed on a BESM-6 high-speed computer.
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.
1910-40-61
satisfying the ascending chain condition on ideals every ideal is the ..... there is a sufficient supply of them); 2) every Krull associated prime is contained ..... three indeterminates over a field F and the maximal ideals N1 = (x, y, z)E and. N2 = (x ...
Thermodynamic properties of H 4SiO 4 in the ideal gas state as evaluated from experimental data
NASA Astrophysics Data System (ADS)
Plyasunov, Andrey V.
2011-07-01
Solid phases of silicon dioxide react with water vapor with the formation of hydroxides and oxyhydroxides of silica. Recent transpiration and mass-spectrometric studies convincingly demonstrate that H 4SiO 4 is the predominant form of silica in vapor phase at water pressure in excess of 10 -2 MPa. Available literature transpiration and solubility data for the reactions of solid SiO 2 phases and low-density water, extending from 424 to 1661 K, are employed for the determination of ?fG0, ?fH0 and S0 of H 4SiO 4 in the ideal gas state at 298.15 K, 0.1 MPa. In total, there are 102 data points from seven literature sources. The resulting values of the thermodynamic functions of H 4SiO 4(g) are: ?fG0 = -1238.51 ± 3.0 kJ mol -1, ?fH0 = -1340.68 ± 3.5 kJ mol -1 and S0 = 347.78 ± 6.2 J K -1 mol -1. These values agree quantitatively with one set of ab initio calculations. The relatively large uncertainties are mainly due to conflicting Cp0 data for H 4SiO 4(g) from various sources, and new determinations of Cp0 would be helpful. The thermodynamic properties of this species, H 4SiO 4(g), are necessary for realistic modeling of silica transport in a low-density water phase. Applications of this analysis may include the processes of silicates condensation in the primordial solar nebula, the precipitation of silica in steam-rich geothermal systems and the corrosion of SiO 2-containing alloys and ceramics in moist environments.
Quantum memory in warm rubidium vapor with buffer gas
Mark Bashkansky; Fredrik K. Fatemi; Igor Vurgaftman
2011-12-02
The realization of quantum memory using warm atomic vapor cells is appealing because of their commercial availability and the perceived reduction in experimental complexity. In spite of the ambiguous results reported in the literature, we demonstrate that quantum memory can be implemented in a single cell with buffer gas using the geometry where the write and read beams are nearly co-propagating. The emitted Stokes and anti-Stokes photons display cross-correlation values greater than 2, characteristic of quantum states, for delay times up to 4 microseconds.
Quantum chemical studies of trace gas adsorption on ice nanoparticles
NASA Astrophysics Data System (ADS)
Schrems, Otto; Ignatov, Stanislav K.; Gadzhiev, Oleg B.; Masunov, Artem E.
2013-04-01
We have investigated the interaction of atmospheric trace gases with crystalline water ice particles of nanoscale size by modern quantum chemical methods. Small ice particles which can be formed in different altitudes play an important role in chemistry and physics of the Earth atmosphere. Knowledge about the uptake and incorporation of atmospheric trace gases in ice particles as well as their interactions with water molecules is very important for the understanding of processes at the air/ice interface. The interaction of the atmospheric trace gases with atmospheric ice nanoparticles is also an important issue for the development of modern physicochemical models. Usually, the interactions between trace gases and small particles considered theoretically apply small-size model complexes or the surface models representing only fragments of the ideal surface. Ice particles consisting of 48, 72, 216 and 270 water molecules with a distorted structure of hexagonal water ice Ih were studied using the new SCC-DFTBA method combining well the advantages of the DFT theory and semiempirical methods of quantum chemistry. The largest clusters correspond to the minimal nanoparticle size which are considered to be crystalline as determined experimentally. The clusters up to (H2O)72 were studied at the B3LYP/6-31++G(d,p) and B3LYP/6-311++G(2d,2p) levels. The larger clusters were studied using DFTBA and DFTB+ methods. Several adsorption complexes for the (H2O)270 water ice cluster were optimized at the RI-BLYP/6-31+G(d) theory level to verify the DFTB+ results. Trace gas molecules were coordinated on different sites of the nanoparticles corresponding to different ice Ih crystal planes: (0001), (10-10), (11-20). As atmospheric trace gases we have chosen CO, CO2, HCO*, HCOH*, HCHO, HCOOH and (HCO)2. which are the possible products and intermediates of the UV photolysis of organic molecules such as HCHCHO adsorbed on the ice surface. The structures of the corresponding coordination complexes, their vibrational frequencies, their adsorption energies and thermodynamic parameters (the enthalpy and the Gibbs free energy of adsorption) were evaluated using the full optimization followed by the frequency calculations. Additionally, the different modes of incorporation of trace gas molecules into the ice particles were considered and the corresponding structural and energetic parameters were evaluated. The transition states for the possible hydration were located and the influence of the water cluster surrounding on the barrier heights was studied as well. Acknowledgements: Financial support by the Russian Foundation for basic Research, project No. 11-03-00085 and German Academic Exchange Service (DAAD) within the Eastpartnership program is greatly acknowledged. O.B.G. and A.E.M. are grateful to DOE NERSC, I2lab, and Institute for Simulation and Training (IST) for making computer time available.
Topological quantum correction to an atomic ideal gas law as a dark energy effect
Kholopov, Eugene V
2012-01-01
The traditional ambiguity about the bulk electrostatic potentials in crystals is due to the conditional convergence of Coulomb series. The classical Ewald approach turns out to be the first one resolving this task as consistent with a translational symmetry. The latter result appears to be directly associated with the thermodynamic limit in crystals. In this case the solution can also be obtained upon direct lattice summation, but after subtracting the mean Bethe potential. As shown, this effect is associated with special periodic boundary conditions at infinity so as to neutralize an arbitrary choice of the unit-cell charge distribution. However, the fact that any additional potential exerted by some charge distribution must in turn affect that charge distribution in equilibrium is not discussed in the case at hand so far. Here we show that in the simplest event of gaseous atomic hydrogen as an example, the self-consistent mean-field-potential correction results in an additional pressure contribution to an i...
A Non-destructive Quantum Gas Microscope for Fermions
NASA Astrophysics Data System (ADS)
Patil, Yogesh; Chakram, Srivatsan; Vengalattore, Mukund
2014-05-01
We have demonstrated a two photon fluorescence imaging technique which allows in situ imaging of a lattice gas of Rb atoms. We report progress on extending this technique to fermionic species, in our case, 6 Li . In contrast to demonstrated means of quantum gas microscopy using molasses cooling, our scheme is not restricted to atomic species amenable to polarization gradient cooling. Furthermore, our imaging scheme is nondestructive in the limit of zero duty cycle of using the Raman transition for imaging and cooling. This presents new opportunities for non-equilibrium many-body studies involving the continuous measurement of system dynamics, measurement based many-body control of the lattice gas and quantum zeno physics. We also describe progress towards augmenting our current system with single site resolution imaging. This work was supported by the NSF and DARPA QuASAR program through a grant from the ARO.
Coulomb quantum kinetics in a dense electron gas
NASA Astrophysics Data System (ADS)
Haug, Hartmut; Ell, Claudia
1992-07-01
The semiclassical Boltzmann equation for a dense electron gas is generalized to a quantum kinetic equation beyond the approximation of isolated collisions. The resulting quantum kinetic equation for the Wigner function contains memory effects, which are determined by the retarded and advanced non- equilibrium Green's functions of the scattered electrons and the screened Coulomb potential. A closed set of equations for the distribution and the spectral functions is given which is exact within the generalized Kadanoff-Baym ansatz and the random-phase approximation. Simplifying approximations are given which result in a quantum kinetic equation with memory kernels similar to those obtained for the electron-phonon scattering. In the limit of completed collisions, the quantum kinetic equation reduces to a Boltzmann equation in which the energy conservation is smeared out due to the finite time interval and due to collision broadening.
NASA Astrophysics Data System (ADS)
Nath, Gorakh
Similarity solutions are obtained for one-dimensional isothermal and adiabatic unsteady flow behind a strong cylindrical shock wave propagating in a rotational axisymmetric dusty gas, which has a variable azimuthal fluid velocity together with a variable axial fluid velocity. The experimental studies and astrophysical observations show that the outer atmosphere of the planets rotates due to rotation of the planets. Macroscopic motion with supersonic speed occurs in an interplanetary atmosphere and shock waves are generated. Thus rotation of planets or stars significantly affect the process taking place in their outer layers, therefore question connected with the explosions in rotating gas atmospheres are of definite astrophysical interest. The shock is assumed to be driven out by a moving piston and the dusty gas to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. It is assumed that the equilibrium flow-condition is maintained and variable energy input is continuously supplied by the piston. The shock Mach number is not infinite, but has a finite value. The azimuthal and axial component of the fluid velocity in the ambient medium are assume to be vary and obey power laws, and the density of the ambient medium is assumed to be constant. In order to obtain the similarity solutions the angular velocity of the ambient medium is assume to be decreasing as the distance from the axis increases. Effects of the variation of the parameter of non-idealness of the gas in the mixture, the mass concentration of solid particles and the ratio of the density of solid particles to the initial density of the gas are investigated.
S. Saikin; L. Fedichkin
2003-05-02
We examine a 31P donor electron spin in a Si crystal to be used for the purposes of quantum computation. The interaction with an uncontrolled system of 29Si nuclear spins influences the electron spin dynamics appreciably. The hyperfine field at the 29Si nuclei positions is non-collinear with the external magnetic field. Quantum operations with the electron wave function, i.e. using magnetic field pulses or electrical gates, change the orientation of hyperfine field and disturb the nuclear spin system. This disturbance produces a deviation of the electron spin qubit from an ideal state, at a short time scale in comparison with the nuclear spin diffusion time. For H_ext=9 T, the estimated error rate is comparable to the threshold value required by the quantum error correction algorithms. The rate is lower at higher external magnetic fields.
Dual-wavelength quantum cascade laser for trace gas spectroscopy
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.
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.
Shortcut to Adiabaticity for an Anisotropic Gas Containing Quantum Defects.
Papoular, D J; Stringari, S
2015-07-10
We present a shortcut to adiabaticity (STA) protocol applicable to 3D unitary Fermi gases and 2D weakly interacting Bose gases containing defects such as vortices or solitons. Our protocol relies on a new class of exact scaling solutions in the presence of anisotropic time-dependent harmonic traps. It connects stationary states in initial and final traps having the same frequency ratios. The resulting scaling laws exhibit a universal form and also apply to the classical Boltzmann gas. The duration of the STA can be made very short so as to realize a quantum quench from one stationary state to another. When applied to an anisotropically trapped superfluid gas, the STA conserves the shape of the quantum defects hosted by the cloud, thereby acting like a perfect microscope, which sharply contrasts with their strong distortion occurring during the free expansion of the cloud. PMID:26207476
Shortcut to Adiabaticity for an Anisotropic Gas Containing Quantum Defects
NASA Astrophysics Data System (ADS)
Papoular, D. J.; Stringari, S.
2015-07-01
We present a shortcut to adiabaticity (STA) protocol applicable to 3D unitary Fermi gases and 2D weakly interacting Bose gases containing defects such as vortices or solitons. Our protocol relies on a new class of exact scaling solutions in the presence of anisotropic time-dependent harmonic traps. It connects stationary states in initial and final traps having the same frequency ratios. The resulting scaling laws exhibit a universal form and also apply to the classical Boltzmann gas. The duration of the STA can be made very short so as to realize a quantum quench from one stationary state to another. When applied to an anisotropically trapped superfluid gas, the STA conserves the shape of the quantum defects hosted by the cloud, thereby acting like a perfect microscope, which sharply contrasts with their strong distortion occurring during the free expansion of the cloud.
Interacting modified Chaplygin gas in loop quantum cosmology
Mubasher Jamil; Ujjal Debnath
2011-02-14
We investigate the background dynamics when dark energy is coupled to dark matter in the universe described by loop quantum cosmology. We consider dark energy of the form modified Chaplygin gas. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. It henceforth resolves the famous cosmic coincidence problem in modern cosmology. The statefinder parameters are also calculated to classify this dark energy model.
Which are the Maximal Ideals ?
Elemer E Rosinger
2006-07-04
Ideals of continuous functions which satisfy an off diagonality condition proved to be important connected with the solution of large classes of nonlinear PDEs, and more recently, in General Relativity and Quantum Gravity. Maximal ideals within those which satisfy that off diagonality condition are important since they lead to differential algebras of generalized functions which can handle the largest classes of singularities. The problem of finding such maximal ideals satisfying the off diagonality condition is formulated within some background detail, and commented upon.
The spin Hall effect in a quantum gas.
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
NASA Astrophysics Data System (ADS)
Nath, Gorakh
Self-similar solutions are obtained for one-dimensional unsteady adiabatic flow behind a spherical shock wave propagating in a dusty gas with conductive and radiative heat fluxes under a gravitational field. The shock is assumed to be driven out by a moving piston and the dusty gas to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. It is assumed that the equilibrium flow-conditions are maintained and variable energy input is continuously supplied by the piston. The heat conduction is express 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 and the absorption coefficient are assumed to vary with temperature and density. The medium is assumed to be under a gravitational field due to heavy nucleus at the origin (Roche Model). The unsteady model of Roche consists of a dusty gas distributed with spherical symmetry around a nucleus having large mass It is assumed that the gravitational effect of the mixture itself can be neglected compared with the attraction of the heavy nucleus. The density of the ambient medium is taken to be constant. Our analysis reveals that after inclusion of gravitational field effect surprisingly the shock strength increases and remarkable difference can be found in the distribution of flow variables. The effects of the variation of the heat transfer parameters, the gravitational parameter and non-idealness of the gas in the mixture are investigated. Also, the effects of an increase in (i) the mass concentration of solid particles in the mixture and (ii) the ratio of the density of solid particles to the initial density of the gas on the flow variables are investigated. It is found that the shock strength is increased with an increase in the value of gravitational parameter. Further, it is investigated that the presence of gravitational field increases the compressibility of the medium, due to which it is compressed and therefore the distance between the piston and the shock surface is reduced. The shock waves in dusty gas under a gravitational field can be important for description of shocks in supernova explosions, in the study of central part of star burst galaxies, nuclear explosion, star formation in shocks, shocks in supernova explosions and shocks in stellar explosion, rupture of a pressurized vessels and explosion in the ionosphere etc. A comparison is made between the solutions in the cases of the gravitating and the non-gravitating medium.
Quantum control of I2 in the gas phase and in condensed phase solid Kr matrix
Apkarian, V. Ara
Quantum control of I2 in the gas phase and in condensed phase solid Kr matrix Christopher J for an example of quantum control in both gas and condensed phase environments. Specifically, we show into account using both exact quantum dynamics and nearly classical theory. For the condensed phase, since
Knapp, Julia L A; Osenbrück, Karsten; Cirpka, Olaf A
2015-10-15
Estimating respiration and photosynthesis rates in streams usually requires good knowledge of reaeration at the given locations. For this purpose, gas-tracer tests can be conducted, and reaeration rate coefficients are determined from the decrease in gas concentration along the river stretch. The typical procedure for analysis of such tests is based on simplifying assumptions, as it neglects dispersion altogether and does not consider possible fluctuations and trends in the input signal. We mathematically derive the influence of these non-idealities on estimated reaeration rates and how they are propagated onto the evaluation of aerobic respiration and photosynthesis rates from oxygen monitoring. We apply the approach to field data obtained from a gas-tracer test using propane in a second-order stream in Southwest Germany. We calculate the reaeration rate coefficients accounting for dispersion as well as trends and uncertainty in the input signals and compare them to the standard approach. We show that neglecting dispersion significantly underestimates reaeration, and results between sections cannot be compared if trends in the input signal of the gas tracer are disregarded. Using time series of dissolved oxygen and the various estimates of reaeration, we infer respiration and photosynthesis rates for the same stream section, demonstrating that the bias and uncertainty of reaeration using the different approaches significantly affects the calculation of metabolic rates. PMID:26150069
Roma "La Sapienza", UniversitÃ di
Gas Un gas ideale `e un sistema di particelle puntiformi non interagenti. Nel seguito immag- ineremo che queste particelle possano essere singoli atomi o molecole biatomiche e di uti- lizzare un diatomici. Scrivere un programma che: 1. Stampi sullo schermo una breve descrizione di quel che far`a ; 2
On a slow drift of a massive piston in an ideal gas that remains at mechanical equilibrium
Chernov, Nikolai
the system is at the so called mechanical equilibrium, and according to the laws of thermodynamics this state. Chernov Department of Mathematics University of Alabama at Birmingham Birmingham, AL 35294, USA chernov with gas. However, the system as a whole is not in a true equilibrium state, unless T- = T+, hence
A quantum-gas microscope for fermionic potassium
NASA Astrophysics Data System (ADS)
Cotta, Dylan; Hudson, James; Kelly, Andrew; Peaudecerf, Bruno; Haller, Elmar; Kuhr, Stefan; Single-atom imaging Team
2015-05-01
Recent experiments with single-site resolution and addressing of strongly correlated rubidium atoms in optical lattices have resulted in the direct observation of, e.g., bosonic Mott insulators, and out-of-equilibrium physics. Here we present a quantum-gas microscope for single-atom-resolved fluorescence detection of fermionic 40K. The atoms are held in a single layer of a 1064 nm optical lattice and observed by a high-resolution optical microscope with numerical aperture NA = 0.68. This setup will enable quantum simulation of the Fermi-Hubbard model with single-particle access, allowing for the direct observation and characterization of, e.g., fermionic Mott insulators, Band insulators, metallic phases or Néel antiferromagnets.
External cavity tunable quantum cascade lasers and their applications to trace gas monitoring.
Rao, Gottipaty N; Karpf, Andreas
2011-02-01
Since the first quantum cascade laser (QCL) was demonstrated approximately 16 years ago, we have witnessed an explosion of interesting developments in QCL technology and QCL-based trace gas sensors. QCLs operate in the mid-IR region (3-24??m) and can directly access the rotational vibrational bands of most molecular species and, therefore, are ideally suited for trace gas detection with high specificity and sensitivity. These sensors have applications in a wide range of fields, including environmental monitoring, atmospheric chemistry, medical diagnostics, homeland security, detection of explosive compounds, and industrial process control, to name a few. Tunable external cavity (EC)-QCLs in particular offer narrow linewidths, wide ranges of tunability, and stable power outputs, which open up new possibilities for sensor development. These features allow for the simultaneous detection of multiple species and the study of large molecules, free radicals, ions, and reaction kinetics. In this article, we review the current status of EC-QCLs and sensor developments based on them and speculate on possible future developments. PMID:21283214
Quintessence and (anti-)Chaplygin gas in loop quantum cosmology
Lamon, Raphael; Woehr, Andreas J. [Institut fuer Theoretische Physik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany)
2010-01-15
The concordance model of cosmology contains several unknown components such as dark matter and dark energy. Many proposals have been made to describe them by choosing an appropriate potential for a scalar field. We study four models in the realm of loop quantum cosmology: the Chaplygin gas, an inflationary and radiationlike potential, quintessence and an anti-Chaplygin gas. For the latter we show that all trajectories start and end with a type II singularity and, depending on the initial value, may go through a bounce. On the other hand the evolution under the influence of the first three scalar fields behaves classically at times far away from the big bang singularity and bounces as the energy density approaches the critical density.
Carlisle, TK; Wiesenauer, EF; Nicodemus, GD; Gin, DL; Noble, RD
2013-01-23
Six vinyl-based, imidazolium room-temperature ionic liquid (RTIL) monomers were synthesized and photopolymerized to form dense poly(RTIL) membranes. The effect of polymer backbone (i.e., poly(ethylene), poly(styrene), and poly(acrylate)) and functional cationic substituent (e.g., alkyl, fluoroalkyl, oligo(ethylene glycol), and disiloxane) on ideal CO2/N-2 and CO2/CH4 membrane separation performance was investigated. The vinyl-based poly(RTIL)s were found to be generally less CO2-selective compared to analogous styrene- and acrylate-based poly(RTIL)s. The CO2 permeability of n-hexyl-(69 barrers) and disiloxane- (130 barrers) substituted vinyl-based poly(RTIL)s were found to be exceptionally larger than that of previously studied styrene and acrylate poly(RTIL)s. The CO2 selectivity of oligo(ethylene glycol)-functionalized vinyl poly(RTIL)s was enhanced, and the CO2 permeability was reduced when compared to the n-hexyl-substituted vinyl-based poly(RTIL). Nominal improvement in CO2/CH4 selectivity was observed upon fluorination of the n-hexyl vinyl-based poly(RTIL), with no observed change in CO2 permeability. However, rather dramatic improvements in both CO2 permeability and selectivity were observed upon blending 20 mol % RTIL (emim Tf2N) into the n-hexyl- and disiloxane-functionalized vinyl poly(RTIL)s to form solid liquid composite films.
Wenxian Zhang; Paola Cappellaro; Natania Antler; Brian Pepper; David G. Cory; Viatcheslav V. Dobrovitski; Chandrasekhar Ramanathan; Lorenza Viola
2009-06-12
The 19F spins in a crystal of fluorapatite have often been used to experimentally approximate a one-dimensional spin system. Under suitable multi-pulse control, the nuclear spin dynamics may be modeled to first approximation by a double-quantum one-dimensional Hamiltonian, which is analytically solvable for nearest-neighbor couplings. Here, we use solid-state nuclear magnetic resonance techniques to investigate the multiple quantum coherence dynamics of fluorapatite, with an emphasis on understanding the region of validity for such a simplified picture. Using experimental, numerical, and analytical methods, we explore the effects of long-range intra-chain couplings, cross-chain couplings, as well as couplings to a spin environment, all of which tend to damp the oscillations of the multiple quantum coherence signal at sufficiently long times. Our analysis characterizes the extent to which fluorapatite can faithfully simulate a one-dimensional quantum wire.
Zhang, Wenxian; Antler, Natania; Pepper, Brian; Cory, David G; Dobrovitski, Viatcheslav V; Ramanathan, Chandrasekhar; Viola, Lorenza
2009-01-01
The 19F spins in a crystal of fluorapatite have often been used to experimentally approximate a one-dimensional spin system. Under suitable multi-pulse control, the nuclear spin dynamics may be modeled to first approximation by a double-quantum one-dimensional Hamiltonian, which is analytically solvable for nearest-neighbor couplings. Here, we use solid-state nuclear magnetic resonance techniques to investigate the multiple quantum coherence dynamics of fluorapatite, with an emphasis on understanding the region of validity for such a simplified picture. Using experimental, numerical, and analytical methods, we explore the effects of long-range intra-chain couplings, cross-chain couplings, as well as couplings to a spin environment, all of which tend to damp the oscillations of the multiple quantum coherence signal at sufficiently long times. Our analysis characterizes the extent to which fluorapatite can faithfully simulate a one-dimensional quantum wire.
Doret J. de Ruyter; Ben Spiecker
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 ideals.
NASA Astrophysics Data System (ADS)
Tarasov, S. V.; Kocharovsky, Vl. V.; Kocharovsky, V. V.
2015-09-01
We find a self-similar analytical solution for the grand-canonical-ensemble (GCE) statistics and thermodynamics in the critical region of Bose-Einstein condensation. It is valid for an arbitrary trap, loaded with an ideal gas, in the thermodynamic limit. We show that for the quantities, changing by a finite amount across the critical region, the exact GCE result differs from the corresponding canonical-ensemble result by a factor on the order of unity even in the thermodynamic limit. Thus, a widely used GCE approach does not describe correctly the critical phenomena at the phase transition for the actual systems with a fixed number of particles and yields only an asymptotics far outside the critical region.
Quantum Hall ferromagnet in a two-dimensional electron gas coupled with quantum dots
NASA Astrophysics Data System (ADS)
Gusev, G. M.; Sotomayor, N. M.; Seabra, A. C.; Quivy, A. A.; Lamas, T. E.; Portal, J. C.
2006-08-01
We have studied the magnetoresistance in the two-dimensional electron gas (2DEG) coupled with quantum dots. The structures consist of asymmetrically doped GaAs double quantum wells separated by tunneling GaxAl1-xAs barrier of 50 Å width. On the top of the structure the hexagonal superlattice of the antidots with periodicity 0.6 ?m and diameter 0.2 ?m was patterned in the PMMA resist, which was then covered by the gold gate. When the negative gate voltage is applied, potential of the neighbor antidots is overlapped, and the array of disconnected quantum dots with triangular shape has been formed in the top quantum well. Therefore, bilayer system is transformed to the single layer of electrons, which is strongly coupled with quantum dots separated by tunneling barrier. We observed the sudden jump in the magnetoresistance at filling factor 3, which also reveals a pronounced hysteresis. The data may signal an quantum Hall ferromagnetism associated with pseudospin (layer) ferromagnetic order.
Control of hot-carrier relaxation for realizing ideal quantum-dot intermediate-band solar cells
NASA Astrophysics Data System (ADS)
Tex, David M.; Kamiya, Itaru; Kanemitsu, Yoshihiko
2014-02-01
For intermediate-band solar cells, the broad absorption spectrum of quantum dots (QDs) offers a favorable conversion efficiency, and photocurrent generation via efficient two-step two-photon-absorption (TS-TPA) in QDs is essential for realizing high-performance solar cells. In the last decade, many works were dedicated to improve the TS-TPA efficiency by modifying the QD itself, however, the obtained results are far from the requirements for practical applications. To reveal the mechanisms behind the low TS-TPA efficiency in QDs, we report here on two- and three-beam photocurrent measurements of InAs quantum structures embedded in AlGaAs. Comparison of two- and three-beam photocurrent spectra obtained by subbandgap excitation reveals that the QD TS-TPA efficiency is improved significantly by suppressing the relaxation of hot TS-TPA carriers to unoccupied shallow InAs quantum structure states.
Control of hot-carrier relaxation for realizing ideal quantum-dot intermediate-band solar cells.
Tex, David M; Kamiya, Itaru; Kanemitsu, Yoshihiko
2014-01-01
For intermediate-band solar cells, the broad absorption spectrum of quantum dots (QDs) offers a favorable conversion efficiency, and photocurrent generation via efficient two-step two-photon-absorption (TS-TPA) in QDs is essential for realizing high-performance solar cells. In the last decade, many works were dedicated to improve the TS-TPA efficiency by modifying the QD itself, however, the obtained results are far from the requirements for practical applications. To reveal the mechanisms behind the low TS-TPA efficiency in QDs, we report here on two- and three-beam photocurrent measurements of InAs quantum structures embedded in AlGaAs. Comparison of two- and three-beam photocurrent spectra obtained by subbandgap excitation reveals that the QD TS-TPA efficiency is improved significantly by suppressing the relaxation of hot TS-TPA carriers to unoccupied shallow InAs quantum structure states. PMID:24535195
Ravi Samtaney
2009-02-10
We present a numerical method to solve the linear stability of impulsively accelerated density interfaces in two dimensions such as those arising in the Richtmyer-Meshkov instability. The method uses an Eulerian approach, and is based on an unwind method to compute the temporally evolving base state and a flux vector splitting method for the perturbations. The method is applicable to either gas dynamics or magnetohydrodynamics. Numerical examples are presented for cases in which a hydrodynamic shock interacts with a single or double density interface, and a doubly shocked single density interface. Convergence tests show that the method is spatially second order accurate for smooth flows, and between first and second order accurate for flows with shocks.
condmat/9912229 On the Quantization of the Monoatomic Ideal
RÃ¡cz, ZoltÃ¡n
condÂmat/9912229 14 Dec 1999 On the Quantization of the Monoatomic Ideal Gas E. Fermi translated and Technology, Gaithersburg, Maryland 20899 Introduction A recent experiment [1] has brought a nearlyÂideal gas degeneracy on the equation of state of an ideal gas, in the paper translated here.[2] Fermi confined the gas
Swihart, Mark T.
of how computational quantum chemistry can be used in developing gas phase reaction mechanisms chemistry; Reaction mechanism; Silicon; Aluminum; ab initio 1. Introduction Detailed chemical kineticAssembling gas-phase reaction mechanisms for high temperature inorganic systems based on quantum
NASA Astrophysics Data System (ADS)
Mehedi Faruk, Mir
2015-09-01
The average energy per fermion in the case of a Fermi gas with any kinematic characteristic, trapped under the most general power law potential in d-dimension has been calculated at zero temperature. In a previous paper (Acharyya M 2010 Eur. J Phys. 31 L89) it was shown, in the case of a free ideal Fermi gas, as the dimension increases the average energy approaches the Fermi energy and in infinite dimension the average energy becomes equal to the Fermi energy at T = 0. In this letter it is shown that, for a trapped system at finite dimension the average energy depends on a power law exponent, but as the dimension tends to infinity the average energy coincides with the Fermi energy for any power law exponent. The result obtained in this manuscript is more general, as we can describe the free system as well as any trapped system with an appropriate choice of power law exponent, and is true for any kinematic parameter.
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…
NASA Astrophysics Data System (ADS)
Chen, Xiaohong; Xu, Hongmei; Lin, Na; Xu, Fuchun; Chen, Hangyang; Cai, Duanjun; Kang, Junyong
2015-03-01
A technique for achieving square-shape quantum wells (QWs) against the intrinsic polar discontinuity and interfacial diffusion through self-compensated pair interlayers is reported. Ultrathin low-and-high % pair interlayers that have diffusion-blocking and self-compensation capacities is proposed to resist the elemental diffusion at nanointerfaces and to grow the theoretically described abrupt rectangular AlGaN/GaN superlattices by metal-organic chemical vapor deposition. Light emission efficiency in such nanostructures is effectively enhanced and the quantum-confined Stark effect could be partially suppressed. This concept could effectively improve the quality of ultrathin QWs in functional nanostructures with other semiconductors or through other growth methods.
Probing a quantum gas with single Rydberg atoms
Nguyen, Huan; Schlagmüller, Michael; Lochead, Graham; Westphal, Karl M; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman
2015-01-01
We present a novel spectroscopic method for probing the \\insitu~density of quantum gases. We exploit the density-dependent energy shift of highly excited {Rydberg} states, which is of the order $10$\\MHz\\,/\\,1E14\\,cm$^{\\text{-3}}$ for \\rubidium~for triplet s-wave scattering. The energy shift combined with a density gradient can be used to localize Rydberg atoms in density shells with a spatial resolution less than optical wavelengths, as demonstrated by scanning the excitation laser spatially across the density distribution. We use this Rydberg spectroscopy to measure the mean density addressed by the Rydberg excitation lasers, and to monitor the phase transition from a thermal gas to a Bose-Einstein condensate (BEC).
Bahrami, Majid
is to be determined using the ideal gas equation and the Benedict-Webb-Rubin equation of state. Analysis (a) From Using the coefficients of Table 4-4 for methane and the given data, the Benedict-Webb-Rubin equation
Measurement-based quantum lattice gas model of fluid dynamics in 2+1 dimensions
NASA Astrophysics Data System (ADS)
Micci, Michael M.; Yepez, Jeffrey
2015-09-01
Presented are quantum simulation results using a measurement-based quantum lattice gas algorithm for Navier-Stokes fluid dynamics in 2+1 dimensions. Numerical prediction of the kinematic viscosity was measured by the decay rate of an initial sinusoidal flow profile. Due to local quantum entanglement in the quantum lattice gas, the minimum kinematic viscosity in the measurement-based quantum lattice gas is lower than achievable in a classical lattice gas. The numerically predicted viscosities precisely match the theoretical predictions obtained with a mean field approximation. Uniform flow profile with double shear layers, on a 16 K ×8 K lattice, leads to the Kelvin-Helmholtz instability, breaking up the shear layer into pairs of counter-rotating vortices that eventually merge via vortex fusion and dissipate because of the nonzero shear viscosity.
Zhou, Hongyi; Zhou, Yaoqi
2002-01-01
The distance-dependent structure-derived potentials developed so far all employed a reference state that can be characterized as a residue (atom)-averaged state. Here, we establish a new reference state called the distance-scaled, finite ideal-gas reference (DFIRE) state. The reference state is used to construct a residue-specific all-atom potential of mean force from a database of 1011 nonhomologous (less than 30% homology) protein structures with resolution less than 2 ?. The new all-atom potential recognizes more native proteins from 32 multiple decoy sets, and raises an average Z-score by 1.4 units more than two previously developed, residue-specific, all-atom knowledge-based potentials. When only backbone and C? atoms are used in scoring, the performance of the DFIRE-based potential, although is worse than that of the all-atom version, is comparable to those of the previously developed potentials on the all-atom level. In addition, the DFIRE-based all-atom potential provides the most accurate prediction of the stabilities of 895 mutants among three knowledge-based all-atom potentials. Comparison with several physical-based potentials is made. PMID:12381853
Thermodynamics of Quantum Ultra-cold Neutron Gas under Gravity of The Earth
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.
Suppression of the quantum-mechanical collapse by repulsive interactions in a quantum gas
Sakaguchi, Hidetsugu [Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Malomed, Boris A. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)
2011-01-15
The quantum-mechanical collapse (alias fall onto the center of particles attracted by potential -r{sup -2}) is a well-known issue in quantum theory. It is closely related to the quantum anomaly, i.e., breaking of the scaling invariance of the respective Hamiltonian by quantization. We demonstrate that the mean-field repulsive nonlinearity prevents the collapse and thus puts forward a solution to the quantum-anomaly problem that differs from that previously developed in the framework of the linear quantum-field theory. This solution may be realized in the 3D or 2D gas of dipolar bosons attracted by a central charge and in the 2D gas of magnetic dipoles attracted by a current filament. In the 3D setting, the dipole-dipole interactions are also taken into regard, in the mean-field approximation, resulting in a redefinition of the scattering length which accounts for the contact repulsion between the bosons. In lieu of the collapse, the cubic nonlinearity creates a 3D ground state (GS), which does not exist in the respective linear Schroedinger equation. The addition of the harmonic trap gives rise to a tristability, in the case when the Schroedinger equation still does not lead to the collapse. In the 2D setting, the cubic nonlinearity is not strong enough to prevent the collapse; however, the quintic term does it, creating the GS, as well as its counterparts carrying the angular momentum (vorticity). Counterintuitively, such self-trapped 2D modes exist even in the case of a weakly repulsive potential r{sup -2}. The 2D vortical modes avoid the phase singularity at the pivot (r=0) by having the amplitude diverging at r{yields}0 instead of the usual situation with the amplitude of the vortical mode vanishing at r{yields}0 (the norm of the mode converges despite of the singularity of the amplitude at r{yields}0). In the presence of the harmonic trap, the 2D quintic model with a weakly repulsive central potential r{sup -2} gives rise to three confined modes, the middle one being unstable, spontaneously developing into a breather. In both the 3D and 2D cases, the GS wave functions are found in a numerical form and in the form of an analytical approximation, which is asymptotically exact in the limit of the large norm.
Zhang, Chi; Liu, Song; Zhou, Hongyi; Zhou, Yaoqi
2004-01-01
Structure prediction on a genomic scale requires a simplified energy function that can efficiently sample the conformational space of polypeptide chains. A good energy function at minimum should discriminate native structures against decoys. Here, we show that a recently developed, residue-specific, all-atom knowledge-based potential (167 atomic types) based on distance-scaled, finite ideal-gas reference state (DFIRE-all-atom) can be substantially simplified to 20 residue types located at side-chain center of mass (DFIRE-SCM) without a significant change in its capability of structure discrimination. Using 96 standard multiple decoy sets, we show that there is only a small reduction (from 80% to 78%) in success rate of ranking native structures as the top 1. The success rate is higher than two previously developed, all-atom distance-dependent statistical pair potentials. Applied to structure selections of 21 docking decoys without modification, the DFIRE-SCM potential is 29% more successful in recognizing native complex structures than an all-atom statistical potential trained by a database of dimeric interfaces. The potential also achieves 92% accuracy in distinguishing true dimeric interfaces from artificial crystal interfaces. In addition, the DFIRE potential with the C? positions as the interaction centers recognizes 123 native structures out of a comprehensive 125-protein TOUCHSTONE decoy set in which each protein has 24,000 decoys with only C? positions. Furthermore, the performance by DFIRE-SCM on newly established 25 monomeric and 31 docking Rosetta-decoy sets is comparable to (or better than in the case of monomeric decoy sets) that of a recently developed, all-atom Rosetta energy function enhanced with an orientation-dependent hydrogen bonding potential. PMID:14739325
Observation of quantum-measurement backaction with an ultracold atomic gas
Loss, Daniel
ARTICLES Observation of quantum-measurement backaction with an ultracold atomic gas KATER W. MURCH1 . However, previous efforts have lacked the means to measure the motion of an atomic ensemble at the quantum (and which, for our set-up, can be treated as independent to a good approximation) within the resonator
Experimental demonstration and exploration of quantum lattice gas algorithms
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 ...
Zevenhoven, Ron
PET 424304 2015 Exercises 3+4 of 4 10 Feb + 13 Feb 2015 1. ideal gas: s = s2- s1 = cp·ln(T2/T1,1 kWh/kg Al) This is also the minimum exergy input need for Al production from pure Al2O3. PET 424304 be neglected for this purity !) molkJ n bn b i i i o ichemi o /7020 , #12;PET 424304 2015 Exercises 3+4 of 4
Zevenhoven, Ron
PET 424304 2013 Exercises 1+2 of 4 12 Feb + 14 Feb 2013 1. ideal gas: s = s2- s1 = cp·ln(T2/T1,1 kWh/kg Al) This is also the minimum exergy input need for Al production from pure Al2O3. PET 424304 be neglected for this purity !) molkJ n bn b i i i o ichemi o /7020 , #12;PET 424304 2013 Exercises 1+2 of 4
Ideal Sub. Ideal Basic Ideal Super. CORRELATIONWITHIDEALMATRIX(R)
Li, Fei-Fei
*** ** *** hV4 * *** *** ** TOS * *** *** *** PPA * * *** ** * RSC * * *** *** ** FFA * *** *** *** * LOC 0.1 0 Subordinate Ideal Basic Ideal Superordinate ns *** *** * * V1 ** * * V2 * * V3v ** ** ** hV4 *** ** * TOS. In Margolis & Laurence (eds.) Concepts: Core readings (MIT Press, 2011). References0.30 0.02 r LOC TOS FFA PPA
Quantum lattice gas model of Fermi systems with relativistic energy relations
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.
Construction of a quantum gas microscope for fermionic atoms
Ramasesh, Vinay (Vinay V.)
2013-01-01
This thesis reports the construction of a novel apparatus for experiments with ultracold atoms in optical lattices: the Fermi gas microscope. Improving upon similar designs for bosonic atoms, our Fermi gas microscope has ...
Prime ideals in quantum algebras
Russell, Ewan
The central objects of study in this thesis are quantized coordinate algebras. These algebras originated in the 1980s in the work of Drinfeld and Jumbo and are noncommutative analogues of coordinate rings of algebraic ...
IDEAL FACTORIZATION KEITH CONRAD
Lozano-Robledo, Alvaro
IDEAL FACTORIZATION KEITH CONRAD 1. Introduction We will prove here the fundamental theorem of ideal theory in number fields: every nonzero proper ideal in the integers of a number field admits unique factorization into a product of nonzero prime ideals. Then we will explore how far the techniques
Single-atom imaging of fermions in a quantum-gas microscope
NASA Astrophysics Data System (ADS)
Haller, Elmar; Hudson, James; Kelly, Andrew; Cotta, Dylan A.; Peaudecerf, Bruno; Bruce, Graham D.; Kuhr, Stefan
2015-09-01
Single-atom-resolved detection in optical lattices using quantum-gas microscopes has enabled a new generation of experiments in the field of quantum simulation. Although such devices have been realized with bosonic species, a fermionic quantum-gas microscope has remained elusive. Here we demonstrate single-site- and single-atom-resolved fluorescence imaging of fermionic potassium-40 atoms in a quantum-gas microscope set-up, using electromagnetically-induced-transparency cooling. We detected on average 1,000 fluorescence photons from a single atom within 1.5 s, while keeping it close to the vibrational ground state of the optical lattice. A quantum simulator for fermions with single-particle access will be an excellent test bed to investigate phenomena and properties of strongly correlated fermionic quantum systems, allowing direct measurement of ordered quantum phases and out-of-equilibrium dynamics, with access to quantities ranging from spin-spin correlation functions to many-particle entanglement.
Ideal Sub. Ideal Basic Ideal Super. CORRELATIONWITHIDEALMATRIX(R)
Li, Fei-Fei
*** ** *** hV4 * *** *** ** TOS * *** *** *** PPA * * *** ** * RSC * * *** *** ** FFA * *** *** *** * LOC 0.1 0 Subordinate Ideal Basic Ideal Superordinate ns *** *** * * V1 ** * * V2 * * V3v ** ** ** hV4 *** ** * TOS in the visual system may optimize basic-level categorizations 0.30 0.02 r LOC TOS FFA PPA hV4 V3v V2 V1 RSC LOC
Single-atom imaging of fermions in a quantum-gas microscope
Haller, Elmar; Kelly, Andrew; Cotta, Dylan A; Peaudecerf, Bruno; Bruce, Graham D; Kuhr, Stefan
2015-01-01
Single-atom-resolved detection in optical lattices using quantum-gas microscopes has enabled a new generation of experiments in the field of quantum simulation. Fluorescence imaging of individual atoms has so far been achieved for bosonic species with optical molasses cooling, whereas detection of fermionic alkaline atoms in optical lattices by this method has proven more challenging. Here we demonstrate single-site- and single-atom-resolved fluorescence imaging of fermionic potassium-40 atoms in a quantum-gas microscope setup using electromagnetically-induced-transparency cooling. We detected on average 1000 fluorescence photons from a single atom within 1.5s, while keeping it close to the vibrational ground state of the optical lattice. Our results will enable the study of strongly correlated fermionic quantum systems in optical lattices with resolution at the single-atom level, and give access to observables such as the local entropy distribution and individual defects in fermionic Mott insulators or anti-...
NASA Astrophysics Data System (ADS)
Ivanov, V. A.
2010-12-01
The possibility of ensuring equivalence in operation and efficiency of real cycles with intermediate cooling (heating) and isothermal-adiabatic compressions (expansion) in ideal simple cycles formed on the T- S diagrams in the second stage of real cycles. The possibility of using the equivalence of cycles for determining the maximum efficiency of operation of real cycles is demonstrated.
Quantum mechanical Carnot engine
C. M. Bender; D. C. Brody; B. K. Meister
2000-07-03
A cyclic thermodynamic heat engine runs most efficiently if it is reversible. Carnot constructed such a reversible heat engine by combining adiabatic and isothermal processes for a system containing an ideal gas. Here, we present an example of a cyclic engine based on a single quantum-mechanical particle confined to a potential well. The efficiency of this engine is shown to equal the Carnot efficiency because quantum dynamics is reversible. The quantum heat engine has a cycle consisting of adiabatic and isothermal quantum processes that are close analogues of the corresponding classical processes.
Ideal clocks—a convenient fiction
NASA Astrophysics Data System (ADS)
Lorek, Krzysztof; Louko, Jorma; Dragan, Andrzej
2015-09-01
We show that no device built according to the rules of quantum field theory can measure proper time along its path. Highly accelerated quantum clocks experience the Unruh effect, which inevitably influences their time rate. This contradicts the concept of an ideal clock, whose rate should only depend on the instantaneous velocity.
Quantum Control by Imaging : The Zeno effect in an ultracold lattice gas
Y. S. Patil; S. Chakram; M. Vengalattore
2014-11-11
We demonstrate the control of quantum tunneling in an ultracold lattice gas by the measurement backaction imposed by an imaging process. A {\\em in situ} imaging technique is used to acquire repeated images of an ultracold gas confined in a shallow optical lattice. The backaction induced by these position measurements modifies the coherent quantum tunneling of atoms within the lattice. By smoothly varying the rate at which spatial information is extracted from the atomic ensemble, we observe the continuous crossover from the 'weak measurement regime' where position measurements have little influence on the tunneling dynamics, to the 'strong measurement regime' where measurement-induced localization causes a large suppression of tunneling. This suppression of coherent tunneling is a manifestation of the Quantum Zeno effect. Our study realizes an experimental demonstration of the paradigmatic Heisenberg microscope in a lattice gas and sheds light on the implications of quantum measurement on the coherent evolution of a mesoscopic quantum system. In addition, this demonstrates a powerful technique for the control of an interacting many-body quantum system via spatially resolved measurement backaction.
Impurity transport through a strongly interacting bosonic quantum gas
Johnson, T. H. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Clark, S. R. [Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Keble College, University of Oxford, Parks Road, Oxford OX1 3PG (United Kingdom); Bruderer, M. [Fachbereich Physik, Universitaet Konstanz, D-78457 Konstanz (Germany); Jaksch, D. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Keble College, University of Oxford, Parks Road, Oxford OX1 3PG (United Kingdom)
2011-08-15
Using near-exact numerical simulations, we study the propagation of an impurity through a one-dimensional Bose lattice gas for varying bosonic interaction strengths and filling factors at zero temperature. The impurity is coupled to the Bose gas and confined to a separate tilted lattice. The precise nature of the transport of the impurity is specific to the excitation spectrum of the Bose gas, which allows one to measure properties of the Bose gas nondestructively, in principle, by observing the impurity; here we focus on the spatial and momentum distributions of the impurity as well as its reduced density matrix. For instance, we show it is possible to determine whether the Bose gas is commensurately filled as well as the bandwidth and gap in its excitation spectrum. Moreover, we show that the impurity acts as a witness to the crossover of its environment from the weakly to the strongly interacting regime, i.e., from a superfluid to a Mott insulator or Tonks-Girardeau lattice gas, and the effects on the impurity in both of these strongly interacting regimes are clearly distinguishable. Finally, we find that the spatial coherence of the impurity is related to its propagation through the Bose gas.
Chemiresistive gas sensors employing solution-processed metal oxide quantum dot films
Liu, Huan, E-mail: huan@mail.hust.edu.cn; Xu, Songman; Li, Min; Shao, Gang; Zhang, Wenkai; Wei, Wendian; He, Mingze [School of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Rd., Wuhan, Hubei 430074 (China); Song, Huaibing; Gao, Liang; Song, Haisheng; Tang, Jiang [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Rd., Wuhan, Hubei 430074 (China)
2014-10-20
We report low-temperature chemiresistive gas sensors based on tin oxide colloidal quantum dots (CQDs), in which the benefits of CQDs such as extremely small crystal size, solution-processability, and tunable surface activity are exploited to enhance the gas-sensing effect. The sensor fabrication is simply employing spin-coating followed by a solid-state ligand exchange treatment at room temperature in air ambient. The optimal gas sensor exhibited rapid and significant decrease in resistance upon H{sub 2}S gas exposure when operated at 70?°C, and it was fully recoverable upon gas release. We observed a power law correlation between the sensor response and H{sub 2}S gas concentration, and the sensing mechanism was discussed using the completely depletion model with a flat band diagram.
Kheruntsyan, Karen
Probing Three-Body Correlations in a Quantum Gas Using the Measurement of the Third Moment gases. Such measurements are able to probe quantum many-body states of interacting systems, often giving in several ultracold gas experiments by measuring the rates of two- and three-body inelastic processes
2004-07-26
Jul 26, 2004 ... A great deal is known about the structure of the irreducible ideals of a ... appearing in such a representation is an invariant, and each such .... Completely irreducible ideals can be characterized in various ways as we demon-.
Jayanta Ghosh; T. K. Samanta
2010-10-12
In this paper we have studied the relation between the fuzzy left (respectively right) ideals of $\\Gamma-$semiring and that of operator semiring. Thereafter, we have established that the Lattices of all fuzzy left (respectively right) ideal of $\\Gamma-$semiring is equivalent to that of Left operator semiring. Also we have established few properties relating the $k-$ideals and $h-$ideals of $\\Gamma-$semiring with that of operator semiring.
Chemical Potential Jump during Evaporation of a Quantum Bose Gas
Bedrikova, E A
2013-01-01
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.
Chemical Potential Jump during Evaporation of a Quantum Bose Gas
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.
Cooling an electron gas using quantum dot based electronic refrigeration
Prance, Jonathan Robert
2009-10-13
of linear transport (VSD = VS?VD = 0) in this situation was given by Beenakker [35], and for non-linear transport (VSD 6= 0) by Averin, Korotkov and Likharev [36, 37]. The energy levels for a quantum dot in the linear regime are depicted in Fig- ure 2...
ERIC Educational Resources Information Center
Dosiere, M.
1985-01-01
Background information, procedures used, and typical results obtained are provided for an experiment in which gas chromatography is used to prove the application of quantum symmetry restrictions in homonuclear diatomic molecules. Comparisons between experimental results and theoretical computed values show good agreement, within one to two…
The Hidden Symmetries of Spin-1 Ising Lattice Gas for Usual Quantum Hamiltonians
NASA Astrophysics Data System (ADS)
Payandeh, Farrin
2015-07-01
In this letter, the most common quantum Hamiltonian is exploited in order to compare the definite equivalences, corresponding to possible spin values in a lattice gas model, to those in a spin-1 Ising model. Our approach also requires interpolating both results in a p-state clock model, in order to find the hidden symmetries of both under consideration models.
Quantum Transport through a Tonks-Girardeau Gas
Palzer, Stefan; Zipkes, Christoph; Sias, Carlo; Koehl, Michael [Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE (United Kingdom)
2009-10-09
We investigate the propagation of spin impurity atoms through a strongly interacting one-dimensional Bose gas. The initially well localized impurities are accelerated by a constant force, very much analogous to electrons subject to a bias voltage, and propagate as a one-dimensional impurity spin wave packet. We follow the motion of the impurities in situ and characterize the interaction induced dynamics. We observe a very complex nonequilibrium dynamics, including the emergence of large density fluctuations in the remaining Bose gas, and multiple scattering events leading to dissipation of the impurity's motion.
Observation of Fermi surface deformation in a dipolar quantum gas
NASA Astrophysics Data System (ADS)
Aikawa, K.; Baier, S.; Frisch, A.; Mark, M.; Ravensbergen, C.; Ferlaino, F.
2014-09-01
In the presence of isotropic interactions, the Fermi surface of an ultracold Fermi gas is spherical. Introducing anisotropic interactions can deform the Fermi surface, but the effect is subtle and challenging to observe experimentally. Here, we report on the observation of a Fermi surface deformation in a degenerate dipolar Fermi gas of erbium atoms. The deformation is caused by the interplay between strong magnetic dipole-dipole interaction and the Pauli exclusion principle. We demonstrate the many-body nature of the effect and its tunability with the Fermi energy. Our observation provides a basis for future studies on anisotropic many-body phenomena in normal and superfluid phases.
Creation of a low-entropy quantum gas of polar molecules in an optical lattice
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% ...
Engineering Light: Quantum Cascade Lasers
Claire Gmachl
2010-09-01
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.
Engineering Light: Quantum Cascade Lasers
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.
Negative Differential Conductivity in an Interacting Quantum Gas
NASA Astrophysics Data System (ADS)
Labouvie, Ralf; Santra, Bodhaditya; Heun, Simon; Wimberger, Sandro; Ott, Herwig
2015-07-01
We report on the observation of negative differential conductivity (NDC) in a quantum transport device for neutral atoms employing a multimode tunneling junction. The system is realized with a Bose-Einstein condensate loaded in a one-dimensional optical lattice with high site occupancy. We induce an initial difference in chemical potential at one site by local atom removal. The ensuing transport dynamics are governed by the interplay between the tunneling coupling, the interaction energy, and intrinsic collisions, which turn the coherent coupling into a hopping process. The resulting current-voltage characteristics exhibit NDC, for which we identify atom number-dependent tunneling as a new microscopic mechanism. Our study opens new ways for the future implementation and control of complex neutral atom quantum circuits.
Negative Differential Conductivity in an Interacting Quantum Gas.
Labouvie, Ralf; Santra, Bodhaditya; Heun, Simon; Wimberger, Sandro; Ott, Herwig
2015-07-31
We report on the observation of negative differential conductivity (NDC) in a quantum transport device for neutral atoms employing a multimode tunneling junction. The system is realized with a Bose-Einstein condensate loaded in a one-dimensional optical lattice with high site occupancy. We induce an initial difference in chemical potential at one site by local atom removal. The ensuing transport dynamics are governed by the interplay between the tunneling coupling, the interaction energy, and intrinsic collisions, which turn the coherent coupling into a hopping process. The resulting current-voltage characteristics exhibit NDC, for which we identify atom number-dependent tunneling as a new microscopic mechanism. Our study opens new ways for the future implementation and control of complex neutral atom quantum circuits. PMID:26274404
Why Explanations Lie: Idealization in Explanation
Strevens, Michael
;2. Explaining Boyle's Law Before continuing, let me give an example of a causally distorting explanation's law using the ideal gas model. Boyle's law states that, when kept at a constant temperature is volume, and the constant k's value is determined by the amount of gas and its temperature. Boyle's law
Satyendranath Bose: Co-Founder of Quantum Statistics
ERIC Educational Resources Information Center
Blanpied, William A.
1972-01-01
Satyendranath Bose was first to prove Planck's Law by using ideal quantum gas. Einstein credited Bose for this first step in the development of quantum statistical mechanics. Bose did not realize the importance of his work, perhaps because of peculiar academic settings in India under British rule. (PS)
What does an ideal wall look like? H. Struchtrup
Struchtrup, Henning
What does an ideal wall look like? H. Struchtrup ETH Zürich, Department of Materials, Polymer-007-0066-5 Abstract This paper deals with the interface between a solid and an ideal gas. The surface of the solid is considered to be an ideal wall, if the flux of entropy is continuous, i.e. if the interaction between wall
COMMUTATIVE IDEAL THEORY WITHOUT FINITENESS CONDITIONS: COMPLETELY IRREDUCIBLE IDEALS
Heinzer, William
COMMUTATIVE IDEAL THEORY WITHOUT FINITENESS CONDITIONS: COMPLETELY IRREDUCIBLE IDEALS LASZLO FUCHS, WILLIAM HEINZER, AND BRUCE OLBERDING Abstract.An ideal of a ring is completely the structure of co* *mpletely irrreducible ideals in a commutative ring without finiteness conditions
Condensation dynamics in a quantum-quenched Bose gas.
Smith, Robert P; Beattie, Scott; Moulder, Stuart; Campbell, Robert L D; Hadzibabic, Zoran
2012-09-01
By quenching the strength of interactions in a partially condensed Bose gas, we create a "supersaturated" vapor which has more thermal atoms than it can contain in equilibrium. Subsequently, the number of condensed atoms (N(0)) grows even though the temperature (T) rises and the total atom number decays. We show that the nonequilibrium evolution of the system is isoenergetic and, for small initial N(0), observe a clear separation between T and N(0) dynamics, thus explicitly demonstrating the theoretically expected "two-step" picture of condensate growth. For increasing initial N(0) values, we observe a crossover to classical relaxation dynamics. The size of the observed quench-induced effects can be explained using a simple equation of state for an interacting harmonically trapped atomic gas. PMID:23005294
Quantum State-Resolved Reactive and Inelastic Scattering at Gas-Liquid and Gas-Solid Interfaces
NASA Astrophysics Data System (ADS)
Grütter, Monika; Nelson, Daniel J.; Nesbitt, David J.
2012-06-01
Quantum state-resolved reactive and inelastic scattering at gas-liquid and gas-solid interfaces has become a research field of considerable interest in recent years. The collision and reaction dynamics of internally cold gas beams from liquid or solid surfaces is governed by two main processes, impulsive scattering (IS), where the incident particles scatter in a few-collisions environment from the surface, and trapping-desorption (TD), where full equilibration to the surface temperature (T{TD}? T{s}) occurs prior to the particles' return to the gas phase. Impulsive scattering events, on the other hand, result in significant rotational, and to a lesser extent vibrational, excitation of the scattered molecules, which can be well-described by a Boltzmann-distribution at a temperature (T{IS}>>T{s}). The quantum-state resolved detection used here allows the disentanglement of the rotational, vibrational, and translational degrees of freedom of the scattered molecules. The two examples discussed are (i) reactive scattering of monoatomic fluorine from room-temperature ionic liquids (RTILs) and (ii) inelastic scattering of benzene from a heated (˜500 K) gold surface. In the former experiment, rovibrational states of the nascent HF beam are detected using direct infrared absorption spectroscopy, and in the latter, a resonace-enhanced multi-photon-ionization (REMPI) scheme is employed in combination with a velocity-map imaging (VMI) device, which allows the detection of different vibrational states of benzene excited during the scattering process. M. E. Saecker, S. T. Govoni, D. V. Kowalski, M. E. King and G. M. Nathanson Science 252, 1421, 1991. A. M. Zolot, W. W. Harper, B. G. Perkins, P. J. Dagdigian and D. J. Nesbitt J. Chem. Phys 125, 021101, 2006. J. R. Roscioli and D. J. Nesbitt Faraday Disc. 150, 471, 2011.
NASA Astrophysics Data System (ADS)
Yan, Wei
2015-03-01
We investigate the hydrodynamic theory of metals, offering systematic studies of the linear-response dynamics for an inhomogeneous electron gas. We include the quantum functional terms of the Thomas-Fermi kinetic energy, the von Weizsäcker kinetic energy, and the exchange-correlation Coulomb energies under the local density approximation. The advantages, limitations, and possible improvements of the hydrodynamic theory are transparently demonstrated. The roles of various parameters in the theory are identified. We anticipate that the hydrodynamic theory can be applied to investigate the linear response of complex metallic nanostructures, including quantum effects, by adjusting theory parameters appropriately.
Spontaneous Pattern Formation in an Antiferromagnetic Quantum Gas
Kronjaeger, Jochen; Bongs, Kai [MUARC, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Institut fuer Laser-Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Becker, Christoph; Soltan-Panahi, Parvis; Sengstock, Klaus [Institut fuer Laser-Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)
2010-08-27
In this Letter we report on the spontaneous formation of surprisingly regular periodic magnetic patterns in an antiferromagnetic Bose-Einstein condensate (BEC). The structures evolve within a quasi-one-dimensional BEC of {sup 87}Rb atoms on length scales of a millimeter with typical periodicities of 20...30 {mu}m, given by the spin healing length. We observe two sets of characteristic patterns which can be controlled by an external magnetic field. We identify these patterns as linearly unstable modes within a mean-field approach and calculate their mode structure as well as time and energy scales, which we find to be in good agreement with observations. These investigations open new prospects for controlled studies of symmetry breaking and complex quantum magnetism in bulk BEC.
NASA Astrophysics Data System (ADS)
Skinner, Brian; Fogler, Michael M.
2010-11-01
We describe a variational procedure for calculating the energy of an electron gas in which the long-range Coulomb interaction is truncated, for example by the screening effect of a nearby metallic gate. We use this procedure to compute the quantum capacitance of a two-dimensional electron gas next to a metallic gate as a function of electron density and spin polarization. The accuracy of the method is verified against published Monte Carlo data. The results compare favorably with a recent experiment.
Probing the quantum state of a 1D Bose gas using off-resonant light scattering.
Sykes, A G; Ballagh, R J
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. PMID:22243293
Probing the Quantum State of a 1D Bose Gas Using Off-Resonant Light Scattering
Sykes, A. G.; Ballagh, R. J.
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.
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.
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.
Many-Body Quantum Chemistry for the Electron Gas: Convergent Perturbative Theories
NASA Astrophysics Data System (ADS)
Shepherd, James J.; Grüneis, Andreas
2013-05-01
We investigate the accuracy of a number of wave function based methods at the heart of quantum chemistry for metallic systems. Using the Hartree-Fock wave function as a reference, perturbative (Møller-Plesset) and coupled cluster theories are used to study the uniform electron gas model. Our findings suggest that nonperturbative coupled cluster theories are acceptable for modeling electronic interactions in metals while perturbative coupled cluster theories are not. Using screened interactions, we propose a simple modification to the widely used coupled cluster singles and doubles plus perturbative triples method that lifts the divergent behavior and is shown to give very accurate correlation energies for the homogeneous electron gas.
The Ideal Electromechanical Oscillator System
Osvaldo F. Schilling
2003-10-25
Oscillators and rotators are among the most important physical systems. For centuries the only known rotating systems that actually reached the limits of the ideal situation of undamped periodical motion were the planets in their orbits. Physics had to develop quantum mechanics to discover new systems that actually behaved like ideal, undamped, oscillators or rotators. However, all examples of this latter systems occur in atomic or molecular scale. The objective of the present letter is to show how the limit of ideal oscillating motion can be challenged by a man-made system. We demonstrate how a simple model electromechanical system consisting of a superconducting coil and a magnet can be made to display both mechanical and electrical undamped oscillations for certain experimental conditions. The effect might readily be attainable with the existing materials technologies and we discuss the conditions to circumvent energy losses. The result is a lossless system that might generate hundreds of Ampere of rectified electrical current by means of the periodical conversion between gravitational potential, kinetic, and magnetic energies.
Superfluidity with disorder in a thin film of quantum gas.
Krinner, Sebastian; Stadler, David; Meineke, Jakob; Brantut, Jean-Philippe; Esslinger, Tilman
2013-03-01
We investigate the properties of a strongly interacting superfluid gas of (6)Li(2) Feshbach molecules forming a thin film confined in a quasi-two-dimensional channel with a tunable random potential, creating a microscopic disorder. We measure the atomic current, extract the resistance of the film in a two-terminal configuration, and identify a superfluid state at low disorder strength, which evolves into a normal poorly conducting state for strong disorder. The transition takes place when the chemical potential reaches the percolation threshold of the disorder. The evolution of the conduction properties contrasts with the smooth behavior of the density and compressibility across the transition, measured in situ at equilibrium. These features suggest the emergence of a glasslike phase at strong disorder. PMID:23521243
I. D. Feranchuk; A. A. Ivanov
2004-09-26
Operator method and cumulant expansion are used for nonperturbative calculation of the partition function and the free energy in quantum statistics. It is shown for Boltzmann diatomic molecular gas with some model intermolecular potentials that the zeroth order approximation of the proposed method interpolates the thermodynamic values with rather good accuracy in the entire range of both the Hamiltonian parameters and temperature. The systematic procedure for calculation of the corrections to the zeroth order approximation is also considered.
A. Pinczuk; B. S. Dennis; L. N. Pfeiffer; K. W. West; E. Burstein
1994-01-01
Mechanisms of resonant inelastic light scattering by the electron gas are evaluated here for their impact in the current research of semiconductor nano-structures. Recent experiments in the fractonal quantum Hall regime highlight the power of the resonant inelastic light-scattering method in studies of electron-electron interactions in semiconductors of reduced dimensions. These applications follow from its capabilities to measure spin-density and
Observation of scaling in the dynamics of a strongly quenched quantum gas
Nicklas, Eike; Höfer, Moritz; Johnson, Aisling; Muessel, Wolfgang; Strobel, Helmut; Tomkovi?, Ji?í; Gasenzer, Thomas; Oberthaler, Markus
2015-01-01
We report on the experimental observation of scaling in the time evolution following a sudden quench into the vicinity of a quantum critical point. The experimental system, a two-component Bose gas with coherent exchange between the constituents, allows for the necessary high level of control of parameters as well as the access to time-resolved spatial correlation functions. The theoretical analysis reveals that quenching the system close to the critical point, the energy introduced by the quench leads to a short-time evolution exhibiting crossover reminiscent of the finite-temperature critical properties in the system's universality class. Observing the time evolution after a quench represents a paradigm shift in accessing and probing experimentally universal properties close to a quantum critical point and allows in a new way benchmarking of quantum many-body theory with experiments.
Observation of scaling in the dynamics of a strongly quenched quantum gas
Eike Nicklas; Markus Karl; Moritz Höfer; Aisling Johnson; Wolfgang Muessel; Helmut Strobel; Ji?í Tomkovi?; Thomas Gasenzer; Markus Oberthaler
2015-09-07
We report on the experimental observation of scaling in the time evolution following a sudden quench into the vicinity of a quantum critical point. The experimental system, a two-component Bose gas with coherent exchange between the constituents, allows for the necessary high level of control of parameters as well as the access to time-resolved spatial correlation functions. The theoretical analysis reveals that quenching the system close to the critical point, the energy introduced by the quench leads to a short-time evolution exhibiting crossover reminiscent of the finite-temperature critical properties in the system's universality class. Observing the time evolution after a quench represents a paradigm shift in accessing and probing experimentally universal properties close to a quantum critical point and allows in a new way benchmarking of quantum many-body theory with experiments.
Quantum-defect method and valence excitons in rare-gas solids
NASA Astrophysics Data System (ADS)
Saile, V.; Reininger, R.; Laporte, P.; Steinberger, I. T.; Findley, G. L.
1988-06-01
In Resca's Comment on three of our papers (preceding paper), he attributes to us a much greater criticism of the quantum-defect method applied to valence excitons than we ourselves originally intended. In this Reply, we attempt to clarify the issue (i) by stating very explicitly where we differ with the original Resca-Resta quantum-defect model, and (ii) by recapitulating the experimental results which support our conclusions. In particular, we find ourselves in full agreement with the basic Resca-Resta nonstructural theory of rare-gas excitons. Unlike the original Resca-Resta quantum-defect model, however, we attribute nonatomic contributions to the exciton short-ranged potentials.
Quantum gas microscopy with spin, atom-number, and multilayer readout
NASA Astrophysics Data System (ADS)
Preiss, Philipp M.; Ma, Ruichao; Tai, M. Eric; Simon, Jonathan; Greiner, Markus
2015-04-01
Atom- and site-resolved experiments with ultracold atoms in optical lattices provide a powerful platform for the simulation of strongly correlated materials. In this Rapid Communication, we present a toolbox for the preparation, control, and site-resolved detection of a tunnel-coupled bilayer degenerate quantum gas. Using a collisional blockade, we engineer occupation-dependent interplane transport which enables us to circumvent light-assisted pair loss during imaging and count n =0 to n =3 atoms per site. We obtain the first number- and site-resolved images of the Mott insulator "wedding cake" structure and observe the emergence of antiferromagnetic ordering across a magnetic quantum phase transition. We are further able to employ the bilayer system for spin-resolved readout of a mixture of two hyperfine states. This work opens the door to direct detection of entanglement and Kosterlitz-Thouless-type phase dynamics, as well as studies of coupled planar quantum materials.
Single-atom imaging of fermions in a quantum-gas microscope
Elmar Haller; James Hudson; Andrew Kelly; Dylan A. Cotta; Bruno Peaudecerf; Graham D. Bruce; Stefan Kuhr
2015-08-20
Single-atom-resolved detection in optical lattices using quantum-gas microscopes has enabled a new generation of experiments in the field of quantum simulation. Fluorescence imaging of individual atoms has so far been achieved for bosonic species with optical molasses cooling, whereas detection of fermionic alkaline atoms in optical lattices by this method has proven more challenging. Here we demonstrate single-site- and single-atom-resolved fluorescence imaging of fermionic potassium-40 atoms in a quantum-gas microscope setup using electromagnetically-induced-transparency cooling. We detected on average 1000 fluorescence photons from a single atom within 1.5s, while keeping it close to the vibrational ground state of the optical lattice. Our results will enable the study of strongly correlated fermionic quantum systems in optical lattices with resolution at the single-atom level, and give access to observables such as the local entropy distribution and individual defects in fermionic Mott insulators or anti-ferromagnetically ordered phases.
COMMUTATIVE IDEAL THEORY WITHOUT FINITENESS CONDITIONS: COMPLETELY IRREDUCIBLE IDEALS
Heinzer, William
COMMUTATIVE IDEAL THEORY WITHOUT FINITENESS CONDITIONS: COMPLETELY IRREDUCIBLE IDEALS LASZLO FUCHS, WILLIAM HEINZER, AND BRUCE OLBERDING Abstract. An ideal of a ring is completely irreducible ideals in a commutative ring without finiteness conditions. It is known that every ideal of a ring
Ideal Multilinear Maps Based on Ideal Lattices Gu Chunsheng
International Association for Cryptologic Research (IACR)
1 Ideal Multilinear Maps Based on Ideal Lattices Gu Chunsheng School of Computer Engineering of ideal multilinear maps using ideal lattices, which support arbitrary multilinearity level. The security of our construction depends on hardness assumption over ideal lattices. Then, we describe a construction
Interacting Generalised Cosmic Chaplygin gas in Loop quantum cosmology: A singularity free universe
Chowdhury, Ratul
2012-01-01
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 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 nega...
Quantum oscillations in the kinetic energy density: Gradient corrections from the Airy gas
NASA Astrophysics Data System (ADS)
Lindmaa, A.; Mattsson, A. E.; Armiento, R.
2014-08-01
We derive a closed-form expression for the quantum corrections to the kinetic energy density in the Thomas-Fermi limit of a linear potential model system in three dimensions (the Airy gas). The universality of the expression is tested numerically in a number of three-dimensional model systems: (i) jellium surfaces, (ii) confinement in a hydrogenlike potential (the Bohr atom), (iii) particles confined by a harmonic potential in one and (iv) all three dimensions, and (v) a system with a cosine potential (the Mathieu gas). Our results confirm that the usual gradient expansion of extended Thomas-Fermi theory does not describe the quantum oscillations for systems that incorporate surface regions where the electron density drops off to zero. We find that the correction derived from the Airy gas is universally applicable to relevant spatial regions of systems of types (i), (ii), and (iv), but somewhat surprisingly not (iii). We discuss possible implications of our findings to the development of functionals for the kinetic energy density.
Trace-gas sensing using the compliance voltage of an external cavity quantum cascade laser
Phillips, Mark C.; Taubman, Matthew S.
2013-06-04
Quantum cascade lasers (QCLs) are increasingly being used to detect, identify, and measure levels of trace gases in the air. External cavity QCLs (ECQCLs) provide a broadly-tunable infrared source to measure absorption spectra of chemicals and provide high detection sensitivity and identification confidence. Applications include detecting chemical warfare agents and toxic industrial chemicals, monitoring building air quality, measuring greenhouse gases for atmospheric research, monitoring and controlling industrial processes, analyzing chemicals in exhaled breath for medical diagnostics, and many more. Compact, portable trace gas sensors enable in-field operation in a wide range of platforms, including handheld units for use by first responders, fixed installations for monitoring air quality, and lightweight sensors for deployment in unmanned aerial vehicles (UAVs). 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 water vapor 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.
Suppression of quantum collapse in an anisotropic gas of dipolar bosons
Sakaguchi, Hidetsugu; Malomed, Boris A.
2011-09-15
In recent work [Sakaguchi and Malomed, Phys. Rev. A 83, 013607 (2011)], a solution to the problem of the quantum collapse (fall onto the center) in the three-dimensional space with the attractive potential -(U{sub 0}/2)r{sup -2} was proposed, based on the replacement of the linear Schroedinger equation by the Gross-Pitaevskii (GP) equation with the repulsive cubic term. The model applies to a quantum gas of molecules carrying permanent electric dipole moments, with the attraction center representing a fixed electric charge. It was demonstrated that the repulsive nonlinearity suppresses the quantum collapse and creates the corresponding spherically symmetric ground state (GS), which was missing in the case of the linear Schroedinger equation. Here, we aim to extend the analysis to the cylindrical geometry and to eigenstates carrying angular momentum. The cylindrical anisotropy is imposed by a uniform dc field, which fixes the orientation of the dipole moments, thus altering the potential of the attraction to the center. First, we analyze the modification of the condition for the onset of the quantum collapse in the framework of the linear Schroedinger equation with the cylindrically symmetric potential for the states with azimuthal quantum numbers m=0 (the GS) and m=1, 2. The corresponding critical values of the strength of the attractive potential (U{sub 0}){sub cr}(m) are found. Next, a numerical solution of the nonlinear GP equation is developed, which demonstrates the replacement of the quantum collapse by the originally missing eigenstates with m=0,1,2. Their dynamical stability is verified by means of numerical simulations of the perturbed evolution. For m=0, the Thomas-Fermi approximation is presented too, in an analytical form. Crucially important for the solution is the proper choice of the boundary conditions at r{yields}0.
Cavity quantum electrodynamics with many-body states of a two-dimensional electron gas.
Smolka, Stephan; Wuester, Wolf; Haupt, Florian; Faelt, Stefan; Wegscheider, Werner; Imamoglu, Ataç
2014-10-17
Light-matter interaction has played a central role in understanding as well as engineering new states of matter. Reversible coupling of excitons and photons enabled groundbreaking results in condensation and superfluidity of nonequilibrium quasiparticles with a photonic component. We investigated such cavity-polaritons in the presence of a high-mobility two-dimensional electron gas, exhibiting strongly correlated phases. When the cavity was on resonance with the Fermi level, we observed previously unknown many-body physics associated with a dynamical hole-scattering potential. In finite magnetic fields, polaritons show distinct signatures of integer and fractional quantum Hall ground states. Our results lay the groundwork for probing nonequilibrium dynamics of quantum Hall states and exploiting the electron density dependence of polariton splitting so as to obtain ultrastrong optical nonlinearities. PMID:25278508
Fractional Quantum Hall Effects in a Two-Dimensional Atomic Gas
NASA Astrophysics Data System (ADS)
Zhao, Jianshi; Jacome, Louis; Gemelke, Nathan
2014-03-01
Fractional Hall effects in two-dimensional electron gases have dramatically altered the way we look at ordering in quantum many body systems. Despite heroic advances since their discovery, many predictions regarding unique behavior have yet to be observed. We describe new efforts to produce similar effects in cold atomic Bose gases. Previous experiments have observed strong correlation in large ensembles of rapidly rotating few body samples consistent with a description using bosonic analogues of fractional hall states. We describe extensions of these experiments to observe individual systems in a quantum gas micropscope, introduce strong interactions through Feshbach resonance, and extend effects to larger numbers of atoms. The use of impurity atoms to probe fractional hall droplets will also be discussed, as will the extension of these effects to higher spin samples by using multiple internal states of Rubidium-87.
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.
NMR dynamics of quantum discord for spin-carrying gas molecules in a closed nanopore
Yurishchev, M. A.
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.
On decomposing ideals into products of comaximal ideals
Heinzer, William
On decomposing ideals into products of comaximal ideals J. W. Brewer and W. J. Heinzer Department] asserts that if D is a one-dimensional Noethe- rian domain, then each nonzero ideal A of D is a product of pairwise comaximal primary ideals. Another result along these lines is a vari- ant of the Chinese Remainder
Multiplier ideals and jumping numbers Preliminaries on simple complete ideals
Faridi, Sara
Multiplier ideals and jumping numbers Preliminaries on simple complete ideals Main results JUMPING NUMBERS OF A SIMPLE COMPLETE IDEAL IN A TWO DIMENSIONAL REGULAR LOCAL RING Eero Hyry, Tarmo JÂ¨arvilehto 19th July 2006 Eero Hyry, Tarmo JÂ¨arvilehto Jumping numbers of a simple complete ideal #12;Multiplier
On decomposing ideals into products of comaximal ideals
Heinzer, William
On decomposing ideals into products of comaximal ideals J. W. Brewer and W. J. Heinzer Department] asserts that if D is a oneÂdimensional NoetheÂ rian domain, then each nonzero ideal A of D is a product of pairwise comaximal primary ideals. Another result along these lines is a variÂ ant of the Chinese Remainder
Weakly Relativistic Quantum Effects in a Two-Dimensional Electron Gas: Dispersion of Langmuir Waves
NASA Astrophysics Data System (ADS)
Andreev, P. A.; Ivanov, A. Yu.
2015-01-01
A weakly-relativistic quantum-hydrodynamic model for charged spinless particles applied to low-dimensional systems is described in detail. The equations are constructed in the self-consistent field approximation. The Darwin term, the current-current interaction, and the weakly relativistic correction to the kinetic energy, all described by the Breit Hamiltonian, are considered together with the Coulomb interaction. The contributions of the described effects and also of relativistic-temperature effects to the dispersion of the Langmuir waves in a two-dimensional electron gas are calculated. A comparison with the corresponding formula for a three-dimensional system of particles is presented.
Observation of Universal Temperature Scaling in the Quantum Viscosity of a Unitary Fermi Gas
Cao, C; Joseph, J; Wu, H; Petricka, J; Schaefer, T; Thomas, J E
2010-01-01
A Fermi gas of atoms tuned near a Feshbach resonance should obey universal hydrodynamics, where the shear viscosity and other transport coefficients are universal functions of the density and temperature. At temperatures well above the superfluid transition, the viscosity has a universal quantum scale $p_T^3/\\hbar^2$, where $p_T$ is the thermal momentum. We observe the expansion of a unitary Fermi gas in this regime and show that the slowing of the dynamics with increasing temperature $T$ is explained by a shear viscosity that scales precisely as $T^{3/2}$. These results are important for measurement of the shear viscosity just above the critical temperature, where the ratio of the shear viscosity to the entropy density is expected to exhibit a minimum that can be compared to a recent conjecture regarding perfect normal fluids.
Itinerant ferromagnetism of a repulsive atomic Fermi gas: a quantum monte carlo study.
Pilati, S; Bertaina, G; Giorgini, S; Troyer, M
2010-07-16
We investigate the phase diagram of a two-component repulsive Fermi gas at T=0 by means of quantum Monte Carlo simulations. Both purely repulsive and resonant attractive model potentials are considered in order to analyze the limits of the universal regime where the details of interatomic forces can be neglected. The equation of state of both balanced and unbalanced systems is calculated as a function of the interaction strength and the critical density for the onset of ferromagnetism is determined. The energy of the strongly polarized gas is calculated and parametrized in terms of the physical properties of repulsive polarons, which are relevant for the stability of the fully ferromagnetic state. Finally, we analyze the phase diagram in the interaction-polarization plane under the assumption that only phases with homogeneous magnetization can be produced. PMID:20867750
ERIC Educational Resources Information Center
New York State Education Dept., Albany.
This profile of the ideal teacher was compiled by the Commissioner's Student Advisory Committee which is made up of 17 secondary school students representing their respective geographic regions across New York State. Part 1 outlines positive personal characteristics, good teaching methods, and elements of sound teacher-student relationships. Brief…
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
ERIC Educational Resources Information Center
Cram, David D.
1975-01-01
The twelve characteristics of an ideal training course discussed in the article are based on the workshop course Criterion-Referenced Instruction: Analysis, Design and Implementation by Bob Mager and Peter Pipe. Behavioral objectives, provision for student differences, practice, feedback, diverse materials, and progress information are some of the…
Steele, W.V.
2002-07-01
Ideal-gas enthalpies of formation of methyl benzoate, ethyl benzoate, (R)-(+)-limonene, tert-amyl methyl ether, trans-crotonaldehyde, and diethylene glycol are reported. The standard energy of combustion and hence standard enthalpy of formation of each compound in the liquid phase has been measured using an oxygen rotating-bomb calorimeter without rotation. Vapor pressures were measured to a pressure limit of 270 kPa or the lower decomposition point for each of the six compounds using a twin ebulliometric apparatus. Liquid-phase densities along the saturation line were measured for each compound over a range of temperature (ambient to a maximum of 548 K). A differential scanning calorimeter was used to measure two-phase (liquid + vapor) heat capacities for each compound in the temperature region ambient to the critical temperature or lower decomposition point. For methyl benzoate and tert-amyl methyl ether, critical temperatures and critical densities were determined from the DSC results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for each of the remaining compounds. The results of the measurements were combined to derive a series of thermophysical properties including critical temperature, critical density, critical pressure, acentric factor, enthalpies of vaporization (restricted to within {+-}50 K of the temperature region of the experimentally determined vapor pressures), and heat capacities along the saturation line. Wagner-type vapor-pressure equations were derived for each compound. All measured and derived values were compared with those obtained in a search of the literature. Recommended critical parameters are listed for each of the compounds studied. Group-additivity parameters, useful in the application of the Benson gas-phase group-contribution correlations, were derived.
Ideal intersections for radio-frequency trap networks
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.
Obtaining Laws of Thermodynamics for Ideal Gases using Elastic Collisions
Montgomery-Smith, Stephen
2013-01-01
The purpose of this note is to see to what extent ideal gas laws can be obtained from simple Newtonian mechanics, specifically elastic collisions. We present simple one-dimensional situations that seem to validate the laws. The first section describes a numerical simulation that demonstrates the second law of thermodynamics. The second section mathematically demonstrates the adiabatic law of expansion of ideal gases.
Life Cycle of Superfluid Vortices and Quantum Turbulence in the Unitary Fermi Gas
Gabriel Wlaz?owski; Aurel Bulgac; Michael McNeil Forbes; Kenneth J. Roche
2014-07-21
The unitary Fermi gas (UFG) offers an unique opportunity to study quantum turbulence both experimentally and theoretically in a strongly interacting fermionic superfluid. It yields to accurate and controlled experiments, and admits the only dynamical microscopic description via time-dependent density functional theory (DFT) - apart from dilute bosonic gases - of the crossing and reconnection of superfluid vortex lines conjectured by Feynman in 1955 to be at the origin of quantum turbulence in superfluids at zero temperature. We demonstrate how various vortex configurations can be generated by using well established experimental techniques: laser stirring and phase imprinting. New imagining techniques demonstrated by the MIT group [Ku et al. arXiv:1402.7052] should be able to directly visualize these crossings and reconnections in greater detail than performed so far in liquid helium. We demonstrate the critical role played by the geometry of the trap in the formation and dynamics of a vortex in the UFG and how laser stirring and phase imprint can be used to create vortex tangles with clear signatures of the onset of quantum turbulence.
Life cycle of superfluid vortices and quantum turbulence in the unitary Fermi gas
NASA Astrophysics Data System (ADS)
Wlaz?owski, Gabriel; Bulgac, Aurel; Forbes, Michael McNeil; Roche, Kenneth J.
2015-03-01
The unitary Fermi gas (UFG) offers a unique opportunity to study quantum turbulence both experimentally and theoretically in a strongly interacting fermionic superfluid with the highest vortex line density of any known superfluid. It yields to accurate and controlled experiments and admits the only dynamical microscopic description via time-dependent density-functional theory, apart from dilute bosonic gases, of the crossing and reconnection of superfluid vortex lines conjectured by Feynman [R. P. Feynman, Prog. Low Temp. Phys. 1, 17 (1955), 10.1016/S0079-6417(08)60077-3] to be at the origin of quantum turbulence in superfluids at zero temperature. We demonstrate how various vortex configurations can be generated by using well-established experimental techniques: laser stirring and phase imprinting. New imaging techniques demonstrated by Ku et al. [M. J. H. Ku et al., Phys. Rev. Lett. 113, 065301 (2014), 10.1103/PhysRevLett.113.065301] should be able to directly visualize these crossings and reconnections in greater detail than performed so far in liquid helium. We demonstrate the critical role played by the geometry of the trap in the formation and dynamics of a vortex in the UFG and how laser stirring and phase imprint can be used to create vortex tangles with clear signatures of the onset of quantum turbulence.
Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition
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
Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition.
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
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.
ChemTeacher Resource: Ideal Gases with Movable Partition
NSDL National Science Digital Library
2012-08-01
An applet shows two containers of an ideal gas separated by a movable partition. By adjusting temperature and/or number of particles, the user causes the partition to move and can watch the resulting changes.
Percolation properties of non-ideal gas
E. Pechersky; A. Yambartsev
2009-09-28
We estimate locations of the regions of the percolation and of the non-percolation in the plane $(\\lambda,\\beta)$: the Poisson rate -- the inverse temperature, for interacted particle systems in finite dimension Euclidean spaces. Our results about the percolation and about the non-percolation are obtained under different assumptions. The intersection of two groups of the assumptions reduces the results to two dimension Euclidean space, $\\R^2$, and to a potential function of the interactions having a hard core. The technics for the percolation proof is based on a contour method which is applied to a discretization of the Euclidean space. The technics for the non-percolation proof is based on the coupling of the Gibbs field with a branching process.
Schiemangk, Max; Lampmann, Kai; Dinkelaker, Aline; Kohfeldt, Anja; Krutzik, Markus; Kürbis, Christian; Sahm, Alexander; Spießberger, Stefan; Wicht, Andreas; Erbert, Götz; Tränkle, Günther; Peters, Achim
2015-06-10
We present micro-integrated diode laser modules operating at wavelengths of 767 and 780 nm for cold quantum gas experiments on potassium and rubidium. The master-oscillator-power-amplifier concept provides both narrow linewidth emission and high optical output power. With a linewidth (10 ?s) below 1 MHz and an output power of up to 3 W, these modules are specifically suited for quantum optics experiments and feature the robustness required for operation at a drop tower or on-board a sounding rocket. This technology development hence paves the way toward precision quantum optics experiments in space. PMID:26192832
NASA Astrophysics Data System (ADS)
Deng, Nianpei
The two dimensional electron gas subjected to a magnetic field has been a model system in contemporary condensed matter physics which generated many beautiful experiments as well as novel fundamental concepts. These novel concepts are of broad interests and have benefited other fields of research. For example, the observations of conventional odd-denominator fractional quantum Hall states have enriched many-body physics with important concepts such as fractional statistics and composite fermions. The subsequent discovery of the enigmatic even-denominator nu=5/2 fractional quantum Hall state has led to more interesting concepts such as non-Abelian statistics and pairing of composite fermions which can be intimately connected to the electron pairing in superconductivity. Moreover, the observations of stripe phases and reentrant integer quantum Hall states have stimulated research on exotic electron solids which have more intricate structures than the Wigner Crystal. In contrast to fractional quantum Hall states and stripes phases, the reentrant integer quantum Hall states are very little studied and their ground states are the least understood. There is a lack of basic information such as exact filling factors, temperature dependence and energy scales for the reentrant integer quantum Hall states. A critical experimental condition in acquiring this information is a stable ultra-low temperature environment. In the first part of this dissertation, I will discuss our unique setup of 3He immersion cell in a state-of-art dilution refrigerator which achieves the required stability of ultra-low temperature. With this experimental setup, we are able to observe for the first time very sharp magnetotransport features of reentrant integer quantum Hall states across many Landau levels for the first time. I will firstly present our results in the second Landau level. The temperature dependence measurements reveal a surprisingly sharp peak signature that is unique to the reentrant integer quantum Hall states. Such a peak signature allows us to define the energy scale of reentrant integer quantum Hall state. An analysis of the energy scales indicate the collective nature of electron solid states. In the following I will present our results in the third Landau level and higher Landau levels which are used in testing the bubble theory predictions for the reentrant integer quantum Hall states. Currently there is no direct experimental probe of the microscopic structures of the reentrant integer quantum Hall states. Instead, by contrasting their energy scales, we find that certain predictions of the bubble theory are at odds with experimental data in the low Landau level limit. Furthermore, an orbital dependent energy scale from the second Landau level to the fifth Landau level is found which will provide useful insights in determining the bubble structures of these reentrant integer quantum Hall states. It must be appreciated that the reentrant integer quantum Hall states have only been observed in the cleanest GaAs/AlGaAs samples. While the highest electron mobility has been achieved in this system by Molecular Beam Epitaxy technique, further improvements are still necessary to facilitate the study of fragile many-body ground states. However, it is little understood that how different disorder which limits the electron mobility affects the strength of the many-body ground states. In the second part of this dissertation, I will present our work on the impact of alloy disorder on the nu=5/2 fractional quantum Hall state. This work is conducted in a series of specially engineered GaAs/AlGaAs samples with controllable alloy disorder. We are able to quantitatively measure the suppression of the nu=5/2 fractional quantum Hall state by alloy disorder scattering. Surprisingly, the nu=5/2 state is found to develop at significantly reduced mobility compared with the empirical mobility threshold according to prior experiments. An analysis of the results indicates that the short-range alloy disorder and the long-range Coulomb disorder play different r
Theta Bodies for Polynomial Ideals
Parrilo, Pablo A.
Inspired by a question of Lovász, we introduce a hierarchy of nested semidefinite relaxations of the convex hull of real solutions to an arbitrary polynomial ideal called theta bodies of the ideal. These relaxations ...
Dalibard, Jean
2009-01-01
Journal Club, Nature 457 p. 639 (2009) A quantum gas specialist learns about crystals from his own science. Crystals can behave as electrical insulators or conductors. In a few and under right conditions of this phase, its incompressibility (U. Schneider et al, Science 322, 1520; 2008). This work is a crucial step
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
Ferromagnetism of a repulsive atomic Fermi gas in an optical lattice: a quantum Monte Carlo study.
Pilati, S; Zintchenko, I; Troyer, M
2014-01-10
Using continuous-space quantum Monte Carlo methods, we investigate the zero-temperature ferromagnetic behavior of a two-component repulsive Fermi gas under the influence of periodic potentials that describe the effect of a simple-cubic optical lattice. Simulations are performed with balanced and with imbalanced components, including the case of a single impurity immersed in a polarized Fermi sea (repulsive polaron). For an intermediate density below half filling, we locate the transitions between the paramagnetic, and the partially and fully ferromagnetic phases. As the intensity of the optical lattice increases, the ferromagnetic instability takes place at weaker interactions, indicating a possible route to observe ferromagnetism in experiments performed with ultracold atoms. We compare our findings with previous predictions based on the standard computational method used in material science, namely density functional theory, and with results based on tight-binding models. PMID:24483906
ERIC Educational Resources Information Center
Heyting, Frieda
2004-01-01
In reaction to Doret De Ruyter's recent defence of the importance of ideals in education, I advocate cautiousness in three respects. First, I explain the importance of distinguishing ideals more sharply from goals by demonstrating the problems of considering ideals even approximately realisable. Second, I substantiate my doubts about their…
An ytterbium quantum gas microscope with narrow-line laser cooling
Yamamoto, Ryuta; Kuno, Takuma; Kato, Kohei; Takahashi, Yoshiro
2015-01-01
We demonstrate site-resolved imaging of individual bosonic $^{174}\\mathrm{Yb}$ atoms in a Hubbard-regime two-dimensional optical lattice with a short lattice constant of 266 nm. To suppress the heating by probe light with the $^1S_0$-$^1P_1$ transition of the wavelength $\\lambda$ = 399 nm for high-resolution imaging and preserve atoms at the same lattice sites during the fluorescence imaging, we simultaneously cool atoms by additionally applying narrow-line optical molasses with the $^1S_0$-$^3P_1$ transition of the wavelength $\\lambda$ = 556 nm. We achieve a low temperature of $T = 7.4(1.3)\\ \\mu\\mathrm{K}$, corresponding to a mean oscillation quantum number along the horizontal axes of 0.22(4) during imaging process. We detect on average 200 fluorescence photons from a single atom within 400 ms exposure time, and estimate the detection fidelity of 87(2)%. The realization of a quantum gas microscope with enough fidelity for Yb atoms in a Hubbard-regime optical lattice opens up the possibilities for studying v...
NASA Astrophysics Data System (ADS)
Cenatiempo, S.; Giuliani, A.
2014-07-01
We present a renormalization group construction of a weakly interacting Bose gas at zero temperature in the two-dimensional continuum, both in the quantum critical regime and in the presence of a condensate fraction. The construction is performed within a rigorous renormalization group scheme, borrowed from the methods of constructive field theory, which allows us to derive explicit bounds on all the orders of renormalized perturbation theory. Our scheme allows us to construct the theory of the quantum critical point completely, both in the ultraviolet and in the infrared regimes, thus extending previous heuristic approaches to this phase. For the condensate phase, we solve completely the ultraviolet problem and we investigate in detail the infrared region, up to length scales of the order (? ^3? _0)^{-1/2} (here ? is the interaction strength and ? _0 the condensate density), which is the largest length scale at which the problem is perturbative in nature. We exhibit violations to the formal Ward Identities, due to the momentum cutoff used to regularize the theory, which suggest that previous proposals about the existence of a non-perturbative non-trivial fixed point for the infrared flow should be reconsidered.
Serena Cenatiempo; Alessandro Giuliani
2014-07-18
We present a renormalization group construction of a weakly interacting Bose gas at zero temperature in the two-dimensional continuum, both in the quantum critical regime and in the presence of a condensate fraction. The construction is performed within a rigorous renormalization group scheme, borrowed from the methods of constructive field theory, which allows us to derive explicit bounds on all the orders of renormalized perturbation theory. Our scheme allows us to construct the theory of the quantum critical point completely, both in the ultraviolet and in the infrared regimes, thus extending previous heuristic approaches to this phase. For the condensate phase, we solve completely the ultraviolet problem and we investigate in detail the infrared region, up to length scales of the order $(\\lambda^3 \\rho_0)^{-1/2}$ (here $\\lambda$ is the interaction strength and $\\rho_0$ the condensate density), which is the largest length scale at which the problem is perturbative in nature. We exhibit violations to the formal Ward Identities, due to the momentum cutoff used to regularize the theory, which suggest that previous proposals about the existence of a non-perturbative non-trivial fixed point for the infrared flow should be reconsidered.
Fractional quantum Hall states of a Bose gas with a spin-orbit coupling
NASA Astrophysics Data System (ADS)
Graß, T.; Juliá-Díaz, B.; Burrello, M.; Lewenstein, M.
2013-07-01
We study the fractional quantum Hall phases of a pseudospin-1/2 Bose gas in an artificial gauge field. In addition to an external magnetic field, the gauge field mimics an intrinsic spin-orbit coupling of the Rashba type. While the spin degeneracy of the Landau levels is lifted by the spin-orbit coupling, the crossing of two Landau levels at certain coupling strengths gives rise to a new degeneracy. We therefore take into account two Landau levels and perform exact diagonalization of the many-body Hamiltonian. We study and characterize the quantum Hall phases which occur in the vicinity of the degeneracy point. Notably, we describe the different states appearing at the Laughlin fillings, ? = 1/2 and ? = 1/4. While for these filling factors incompressible phases disappear at the degeneracy point, we find gaps in the spectra of denser systems at ? = 3/2 and ? = 2. For filling factors ? = 2/3 and ? = 4/3, we discuss the connection of the exact ground states to the non-Abelian spin singlet states, obtained as the ground states of (k + 1)-body contact interactions.
Common physical mechanism for integer and fractional quantum Hall effects
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 $\
Eulerian and Newtonian dynamics of quantum particles
NASA Astrophysics Data System (ADS)
Rashkovskiy, S. A.
2013-06-01
We derive the classical equations of hydrodynamics (the Euler and continuity equations), from which the Schrödinger equation follows as a limit case. It is shown that the statistical ensemble corresponding to a quantum system and described by the Schrödinger equation can be considered an inviscid gas that obeys the ideal gas law with a quickly oscillating sign-alternating temperature. This statistical ensemble performs the complex movements consisting of smooth average movement and fast oscillations. It is shown that the average movements of the statistical ensemble are described by the Schrödinger equation. A model of quantum motion within the limits of classical mechanics that corresponds to the hydrodynamic system considered is suggested.
NASA Astrophysics Data System (ADS)
Luo, Ercang
2012-06-01
This paper analyzes the thermodynamic cycle of oscillating-flow regenerative machines. Unlike the classical analysis of thermodynamic textbooks, the assumptions for pistons' movement limitations are not needed and only ideal flowing and heat transfer should be maintained in our present analysis. Under such simple assumptions, the meso-scale thermodynamic cycles of each gas parcel in typical locations of a regenerator are analyzed. It is observed that the gas parcels in the regenerator undergo Lorentz cycle in different temperature levels, whereas the locus of all gas parcels inside the regenerator is the Ericson-like thermodynamic cycle. Based on this new finding, the author argued that ideal oscillating-flow machines without heat transfer and flowing losses is not the Stirling cycle. However, this new thermodynamic cycle can still achieve the same efficiency of the Carnot heat engine and can be considered a new reversible thermodynamic cycle under two constant-temperature heat sinks.
OBTAINING LAWS OF THERMODYNAMICS FOR IDEAL GASES USING ELASTIC COLLISIONS
Montgomery-Smith, Stephen
Newtonian. For example, the motion is reversible, thus demonstrating that the second law of thermodynamics N molecules of gas B in the right half of the container. The molecules obey Newton's laws of motion that Newton's laws of motion are all that are needed to predict the ideal gas laws, and that the collisions
Kim, Jai Sam
Critical nature of ideal Bose-Einstein condensation: Similarity with Yang-Lee theory of phase of the thermodynamic potential of an ideal Bose gas is connected with the physical root z0 1 of the inverse of an ideal Bose gas and found that below the critical temperature, particles begin to condense in the lowest
of the sensor such as gate bias dependence of sensitivity, relationship between the required work in tunneling probability for TFETs with temperature are explained. It is shown that TFET gas-sensors can of thin films and heterogeneous catalysis. Specially, the gas-sensors based on the work- function
Characterization of Pb??Te?? quantum dot thin film synthesized by inert gas condensation.
Mahdy, Manal A; Mahdy, Iman A; El Zawawi, I K
2015-01-01
Air-stable and thermal-stable lead telluride quantum dot was successfully prepared on glass substrate by inert gas condensation (IGC) method. Argon (Ar) is the inert gas used during deposition process with a constant flow rate of 3 × 10(-3)Torr. The effect of heat-treatment process at different times was studies for structure, optical and electrical properties for nanocrystalline thin films. The structures of the as deposited and heat-treated films were investigated using grazing incident in-plane X-ray diffraction (GIIXD). The GIIXD pattern showed nanostructure face centered cubic structure of PbTe thin films. The energy dispersive X-ray analysis (EDX) of as deposited PbTe thin film was carried out and showed that the atomic ratio of Pb/Te was 24/76. The particle size of the as deposited PbTe film and after stored it in an unhumid atmosphere are 6.8 ± 0.3 nm and 7.2 ± 0.3 nm respectively as estimated form TEM image (i.e. in the same level of particle size). However, the particle size was changed to be 11.8 ± 0.3 nm after heat-treated for 5h at 473K. These particle size values of PbTe thin film are smaller than its Bohr radius. The estimated value of optical band gap Eg decreased from 1.71 eV for the as deposited film to 1.62 eV for film heat-treated (5 h at 473K). The dc electrical conductivity is increased with raising temperature in the range (303-473K) for all thin films under investigation. The deduced activation energy decreased from 0.222 eV for as deposited sample to 0.125 eV after heat-treated at 473K for 5 h. PMID:25022502
Characterization of Pb24Te76 quantum dot thin film synthesized by inert gas condensation
NASA Astrophysics Data System (ADS)
Mahdy, Manal A.; Mahdy, Iman A.; El Zawawi, I. K.
2015-01-01
Air-stable and thermal-stable lead telluride quantum dot was successfully prepared on glass substrate by inert gas condensation (IGC) method. Argon (Ar) is the inert gas used during deposition process with a constant flow rate of 3 × 10-3 Torr. The effect of heat-treatment process at different times was studies for structure, optical and electrical properties for nanocrystalline thin films. The structures of the as deposited and heat-treated films were investigated using grazing incident in-plane X-ray diffraction (GIIXD). The GIIXD pattern showed nanostructure face centered cubic structure of PbTe thin films. The energy dispersive X-ray analysis (EDX) of as deposited PbTe thin film was carried out and showed that the atomic ratio of Pb/Te was 24/76. The particle size of the as deposited PbTe film and after stored it in an unhumid atmosphere are 6.8 ± 0.3 nm and 7.2 ± 0.3 nm respectively as estimated form TEM image (i.e. in the same level of particle size). However, the particle size was changed to be 11.8 ± 0.3 nm after heat-treated for 5 h at 473 K. These particle size values of PbTe thin film are smaller than its Bohr radius. The estimated value of optical band gap Eg decreased from 1.71 eV for the as deposited film to 1.62 eV for film heat-treated (5 h at 473 K). The dc electrical conductivity is increased with raising temperature in the range (303-473 K) for all thin films under investigation. The deduced activation energy decreased from 0.222 eV for as deposited sample to 0.125 eV after heat-treated at 473 K for 5 h.
Quantum chaos in ultracold collisions of gas-phase erbium atoms
NASA Astrophysics Data System (ADS)
Frisch, Albert; Mark, Michael; Aikawa, Kiyotaka; Ferlaino, Francesca; Bohn, John L.; Makrides, Constantinos; Petrov, Alexander; Kotochigova, Svetlana
2014-03-01
Atomic and molecular samples reduced to temperatures below one microkelvin, yet still in the gas phase, afford unprecedented energy resolution in probing and manipulating the interactions between their constituent particles. As a result of this resolution, atoms can be made to scatter resonantly on demand, through the precise control of a magnetic field. For simple atoms, such as alkalis, scattering resonances are extremely well characterized. However, ultracold physics is now poised to enter a new regime, where much more complex species can be cooled and studied, including magnetic lanthanide atoms and even molecules. For molecules, it has been speculated that a dense set of resonances in ultracold collision cross-sections will probably exhibit essentially random fluctuations, much as the observed energy spectra of nuclear scattering do. According to the Bohigas-Giannoni-Schmit conjecture, such fluctuations would imply chaotic dynamics of the underlying classical motion driving the collision. This would necessitate new ways of looking at the fundamental interactions in ultracold atomic and molecular systems, as well as perhaps new chaos-driven states of ultracold matter. Here we describe the experimental demonstration that random spectra are indeed found at ultralow temperatures. In the experiment, an ultracold gas of erbium atoms is shown to exhibit many Fano-Feshbach resonances, of the order of three per gauss for bosons. Analysis of their statistics verifies that their distribution of nearest-neighbour spacings is what one would expect from random matrix theory. The density and statistics of these resonances are explained by fully quantum mechanical scattering calculations that locate their origin in the anisotropy of the atoms' potential energy surface. Our results therefore reveal chaotic behaviour in the native interaction between ultracold atoms.
A quantum chemistry study for ionic liquids applied to gas capture and separation.
Damas, Giane B; Dias, Amina B A; Costa, Luciano T
2014-07-31
In recent years, the global climate change is in evidence and it is almost a consensus that it is caused by the greenhouse gases emissions. An alternative to reduce these emissions is carbon capture and storage (CCS), which employs solvents based on amine compounds. In this scene, ionic liquids (IL) have been investigated to a greater extent for this application. In this work, we make an evaluation of interactions between gases (CO2, SO2, and H2S) and anion/cation from IL, as well as cation-anion interactions. For this, quantum calculations under vacuum were performed at the B3LYP/6-311+G** level of theory and using the M06-2X functional, where dispersion effects are considered. Among the well-studied systems based on imidazolium cations and fluorinated anions, we also studied the tetraalkylammonium, tetraalkylphosphonium, ether-functionalized imidazolium based systems, and tetrahexylammonium bis(trifluoromethanesulfonyl)imide, [THA][Tf2N], as a potential prototype. The ion pairs evaluated include [Tf2N](-)-based IL, with alkyl chain varying from [C1mim](+) to [C8mim](+) and [C1mim](+)-based IL. We found that the anion becomes more available to interact with gas with the weakening of the cation-anion interaction. [THA][Tf2N] has a binding energy of -274.89 kJ/mol at the B3LYP/6-311+G** level of theory, which is considered energetically interesting to gas capture applications. PMID:24988534
UNIQUE IRREDUNDANT INTERSECTIONS OF COMPLETELY IRREDUCIBLE IDEALS
Heinzer, William
UNIQUE IRREDUNDANT INTERSECTIONS OF COMPLETELY IRREDUCIBLE IDEALS WILLIAM HEINZER AND BRUCE OLBERDING Abstract.An ideal of a commutative ring is completely* * ideal is an intersection of completely irreducible ideals. We characterize the ri* *ngs
Maxwell's demon in the quantum world
Kim, Sang Wook; De Liberato, Simone; Ueda, Masahito
2010-01-01
Maxwell's demon (MD) is a hypothetical being of intelligence that was conceived to illuminate possible limitations of the second law of thermodynamics. Leo Szilard made a classical analysis of the MD, considering an idealized heat engine with one molecule gas, and directly associated the information acquired by measurement with physical entropy to save the second law. Although Szilard's engine (SZE) deals with a truly quantum-mechanical object, namely an engine with a single molecule, surprisingly its fully quantum-mechanical analysis has been elusive except for the measurement process. Here, we present the first complete quantum analysis of the SZE, and report two important findings. First, we derive an analytic expression of the quantum-mechanical work performed by a quantum SZE containing an arbitrary number of molecules, where it is crucial to regard the process of insertion or removal of a wall as a legitimate thermodynamic process. Secondly, we find that the indistinguishability of quantum identical par...
Phillips, Mark C.; Craig, Ian M.
2013-11-03
We analyze the long-term performance and stability of a trace-gas sensor based on an external cavity quantum cascade laser using data collected over a one-year period in a building air monitoring application.
NASA Astrophysics Data System (ADS)
den Hartog, S. G.; van Wees, B. J.; Nazarov, Yu. V.; Klapwijk, T. M.; Borghs, G.
1997-10-01
We have investigated the superconducting-phase-modulated reduction in the resistance of a ballistic quantum point contact (QPC) connected via a disordered two-dimensional electron gas (2DEG) to superconductors. We show that this reduction is caused by coherent Andreev backscattering of holes through the QPC, which increases monotonically by reducing the bias voltage to zero. In contrast, the magnitude of the phase-dependent resistance of the disordered 2DEG displays a nonmonotonic reentrant behavior versus bias voltage.
Thermal photons in QGP and non-ideal effects
Jitesh R. Bhatt; Hiranmaya Mishra; V. Sreekanth
2010-11-09
We investigate the thermal photon production-rates using one dimensional boost-invariant second order relativistic hydrodynamics to find proper time evolution of the energy density and the temperature. The effect of bulk-viscosity and non-ideal equation of state are taken into account in a manner consistent with recent lattice QCD estimates. It is shown that the \\textit{non-ideal} gas equation of state i.e $\\epsilon-3\\,P\\,\
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.
Density-induced processes in quantum gas mixtures in optical lattices
Ole Jürgensen; Klaus Sengstock; Dirk-Sören Lühmann
2014-09-10
We show that off-site processes and multi-orbital physics have a crucial impact on the phase diagram of quantum gas mixtures in optical lattices. In particular, we discuss Bose-Fermi mixtures where the intra- and interspecies interactions induce competing density-induced hopping processes, the so-called bond-charge interactions. Furthermore, higher bands strongly influence tunneling and on-site interactions. We apply a multi-orbital interaction-induced dressing of the lowest band which leads to renormalized hopping processes. These corrections give rise to an extended Hubbard model with intrinsically occupation-dependent parameters. The resulting decrease of the tunneling competes with a decrease of the total on-site interaction energy both affecting the critical lattice depth of the superfluid to Mott insulator transition. In contrast to the standard Bose-Fermi-Hubbard model, we predict a large shift of the transition to shallower lattice depths with increasing Bose-Fermi attraction. The applied theoretical model allows an accurate prediction of the modified tunneling amplitudes and the critical lattice depth both recently observed experimentally.
Gas-Phase Reactivity of Cesium-Containing Species by Quantum Chemistry.
Šulková, Katarína; Cantrel, Laurent; Louis, Florent
2015-09-01
Thermodynamics and kinetics of cesium species reactions have been studied by using high-level quantum chemical tools. A systematic theoretical study has been done to find suitable methodology for calculation of reliable thermodynamic properties, allowing us to determine bimolecular rate constants with appropriate kinetic theories of gas-phase reactions. Four different reactions have been studied in this work: CsO + H2 = CsOH + H (R1), Cs + HI = CsI + H (R2), CsI + H2O = CsOH + HI (R3), and CsI + OH = CsOH + I (R4). All reactions involve steam, hydrogen, and iodine in addition of cesium. Most of the reactions are fast and (R3) and (R4) proceed even without energetic barrier. In terms of chemical reactivity in the reactor coolant system (RCS) in the case of severe accident, it can be expected that there will be no kinetic limitations for main cesium species (CsOH and CsI) transported along the RCS. Cs chemical speciation inside the RCS should be governed by the thermodynamics. PMID:26237575
STRONGLY IRREDUCIBLE IDEALS OF A COMMUTATIVE RING
Heinzer, William
STRONGLY IRREDUCIBLE IDEALS OF A COMMUTATIVE RING William J. Heinzer, Louis J. Ratliff Jr. and David E. Rush Abstract An ideal I of a ring R is said to be strongly irreducible if for ideals J and K of irreducible ideals, strongly irreducible ideals, and prime ideals of a commutative ring R is considered
Be Ye Perfect? Religious Ideals in Education
ERIC Educational Resources Information Center
de Ruyter, Doret J.
2006-01-01
This article explores the meaning of "religious ideals" and their possible role in education. "Religious ideals" are defined as ideals that acquire meaning due to a belief in transcendence or a divine being. Two kinds of religious ideals are being distinguished, namely ideals that are constituted by a belief in a transcendent being and ideals that…
Be ye perfect? Religious ideals in education
Doret J. de Ruyter
2006-01-01
This article explores the meaning of ‘religious ideals’ and their possible role in education. ‘Religious ideals’ are defined as ideals that acquire meaning due to a belief in transcendence or a divine being. Two kinds of religious ideals are being distinguished, namely ideals that are constituted by a belief in a transcendent being and ideals that are being determined by
FK-DLR properties of a quantum multi-type Bose-gas with a repulsive interaction
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.
Size-controlled synthesis of SnO2 quantum dots and their gas-sensing performance
NASA Astrophysics Data System (ADS)
Du, Jianping; Zhao, Ruihua; Xie, Yajuan; Li, Jinping
2015-08-01
Tin dioxide quantum dots (TQDs) with controllable size were synthesized by changing the amount of alkaline reagent in the hydrothermal process. The gas-sensing properties were investigated by operating chemoresistor type sensor. The morphology and structure were characterized by X-ray diffraction, scanning/transmission electron microscopy, UV-vis and Raman spectrometry. The as-synthesized SnO2 shows the characteristics of quantum dots and the narrowest size distribution is about 2-3 nm. The gas-sensing results indicate that the responses are strongly dependent on the size of quantum dots. TQDs with different sizes exhibit different sensitivities and selectivities to volatile toxic chemicals such as aldehyde, acetone, methanol, ethanol and amine. Especially, when the sensors are exposed to 100 ppm triethylamine (TEA), the sensing response value of TQDs with small size is two times higher than that of the large-size TQDs. The maximum response values of TQDs to 1 ppm and 100 ppm TEA are 15 and 153, respectively. The response time is 1 s and the recovery time is 47 s upon exposure to 1 ppm TEA. The results suggest that it is an effective method by regulating the size of SnO2 quantum dots to detect low-concentration hazardous volatile compounds.
Ideals, Education, and Happy Flourishing
ERIC Educational Resources Information Center
de Ruyter, Doret
2007-01-01
In this essay, Doret J. de Ruyter defends the claim that parents as well as professional educators need to impart ideals to children in order to realize their wish that children become happy and flourishing adults. The argument consists of two parts. First, de Ruyter shows how ideals are important to construing the meaning of objective goods.…
Primary Components of Binomial Ideals
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...
An entropic solver for ideal Lagrangian magnetohydrodynamics
Bezard, F.; Despres, B.
1999-09-01
In this paper, the authors adapt to the ideal 1D lagrangian MHD equations a class of numerical schemes of order one in time and space presented in an earlier paper and applied to the gas dynamics system. They use some properties of systems of conservation laws with zero entropy flux which describe fluid models invariant by galilean transformation and reversible for regular solutions. These numerical schemes satisfy an entropy inequality under CFL conditions. In the last section, they describe a particular scheme for the MHD equations and show with some numerical applications its robustness and accuracy. The generalization to full Eulerian multidimensional MHD will be the subject of a forthcoming paper.
Infrared absorption of holes in a parabolic quantum well M. Sundarama)
Geller, Michael R.
candidate for such a test. More importantly, the valence band is composite, i.e., composed of many branches, but also in composite bands. The LuttingerÂKohn Hamiltonian for a hole gas in an ideal parabolic quantum to 0.01 at the center Fig. 1 . The grading was accomplished using the digital alloy technique, i
Constraining parameters of generalized cosmic Chaplygin gas in loop quantum cosmology
NASA Astrophysics Data System (ADS)
Ranjit, Chayan; Debnath, Ujjal
2014-12-01
We have assumed an FRW universe in a loop quantum cosmology (LQC) model, filled with dark matter and Generalized Cosmic Chaplygin gas (GCCG) dark energy, where dark matter follows a linear equation of state. We present the Hubble parameter in terms of the observable parameters ? m0 and H 0 with the redshift z and the other parameters like A, B, w m , ? and ? which coming from our model. From Stern data set (12 points) & SNe Type Ia 292 data (from Riess et al. in Astrophys. J. 607:665, 2004; Astrophys. J. 659:98, 2007; Astier et al. in Astron. Astrophys. 447:31, 2006) we have obtained the bounds of the arbitrary parameters by minimizing the ? 2 test. The best-fit values of the parameters are obtained by 66 %, 90 % and 99 % confidence levels. Next due to joint analysis with Stern + BAO and Stern + BAO + CMB observations, we have also obtained the bounds of the parameters ( A, B) by fixing some other parameters ?, w m and ?. From the best fit values of the parameters, we have obtained the distance modulus ?( z) for our theoretical GCCG model in LQC and from Supernovae Type Ia (Union2 sample 552 data from Amanullah et al. in Astrophys. J. 716:712, 2010 & Riess 292 data from Riess et al. in Astrophys. J. 607:665, 2004; Astrophys. J. 659:98, 2007; Astier et al. in Astron. Astrophys. 447:31, 2006), we have concluded that our model is in agreement with the Supernovae Type Ia sample data. In addition, we have investigated in details about the various types of Future Singularities that may be formed in this model and it is notable that our model is completely free from any types of future singularities.
Some applications of the quantum-lattice-gas model to high- Tc superconductivity
NASA Astrophysics Data System (ADS)
De Jongh, L. J.
1989-12-01
The quantum-lattice-gas model has been introduced by Matsubara and Matsuda to describe the superfluid properties of 4He. It relates the Hamiltonian of a system of hard-core bosonic quasi-particles, hopping on a lattice with nearest-neighbour transfer integral t and interaction v, to that of a spin S = {1}/{2}, Heisenberg antiferromagnet with uniaxial anisotropy. The quasi-particle density in the boson problem maps on the magnetization in an applied magnetic field in the antiferromagnetic problem. Interest in the charged-boson version of this model has recently been revived by its application to the superconductivity (superfluidity) of local pairs of carriers (onsite and/or intersite bipolarons) by Ranninger, Micnas, Alexandrov and Robaszkiewicz. In this paper we investigate some applications of this model to the observed properties of the superconducting oxides. Here we profit from the wealth of knowledge that is available on the antiferromagnetic Heisenberg model with uniaxial anisotropy in a magnetic field. Once the idea is accepted that the superconductivity in the oxides is due to local (real-space pairs), one may directly transpose this knowledge of the magnetic analogues to the boson problem. In particular the comparison between the cubic, BaBiO 3-based superconductors and the quasi 2-dimensional copper-oxide superconductors appears to be quite rewarding. We discuss account of the phase diagrams of T c versus carrier density, the behaviour of the specific heat, the fluctuation effects, the field-dependent effects and the variation of T c with the number of sheets in the superconducting multilayer compounds.
Constraining Parameters of Generalized Cosmic Chaplygin Gas in Loop Quantum Cosmology
Chayan Ranjit; Ujjal Debnath
2014-09-20
We have assumed the FRW universe in loop quantum cosmology (LQC) model filled with the dark matter and the Generalized Cosmic Chaplygin gas (GCCG) type dark energy where dark matter follows the linear equation of state. We present the Hubble parameter in terms of the observable parameters $\\Omega_{m0}$ and $H_{0}$ with the redshift $z$ and the other parameters like $A$, $B$, $w_{m}$, $ \\omega$ and $\\alpha$ which coming from our model. From Stern data set (12 points)\\& SNe Type Ia 292 data (from \\cite{Riess1,Riess2,Astier}) we have obtained the bounds of the arbitrary parameters by minimizing the $\\chi^{2}$ test. The best-fit values of the parameters are obtained by 66\\%, 90\\% and 99\\% confidence levels. Next due to joint analysis with Stern+BAO and Stern+BAO+CMB observations, we have also obtained the bounds of the parameters ($A,B$) by fixing some other parameters $\\alpha$, $w_{m}$ and $\\omega$. From the best fit values of the parameters, we have obtained the distance modulus $\\mu(z)$ for our theoretical GCCG model in LQC and from Supernovae Type Ia (union2 sample 552 data from [\\cite{Amanullah}] \\& Riess 292 data from [\\cite{Riess1,Riess2,Astier}]), we have concluded that our model is in agreement with the Supernovae Type Ia sample data. In addition, we have investigated in details about the various types of Future Singularities that may be formed in this model and it is notable that our model is completely free from any types of future singularities.
Miller, Ezra N.
Multiplier ideals Monomial ideals Log resolutions Cellular resolutions Polyhedral subdivisions References Multiplier ideals of sums via cellular resolutions Ezra Miller University of Minnesota ezra on joint work with Shin-Yao Jow (Michigan) #12;Multiplier ideals Monomial ideals Log resolutions Cellular
Macroscopic transport equations for rarefied gas flows Henning Struchtrup
Struchtrup, Henning
closure problem find additional equations for pressure deviator ij and heat flux qi ideal gas law: p, Springer Berlin-Heidelberg 2005, 258 pages #12;What is an ideal gas? we shall discuss monatomic ideal gases collisions a gas is ideal if · its particles are in free flight most of the time, ri ¿ 1 · the mean
Ideal AFROC and FROC observers.
Khurd, Parmeshwar; Liu, Bin; Gindi, Gene
2010-02-01
Detection of multiple lesions in images is a medically important task and free-response receiver operating characteristic (FROC) analyses and its variants, such as alternative FROC (AFROC) analyses, are commonly used to quantify performance in such tasks. However, ideal observers that optimize FROC or AFROC performance metrics have not yet been formulated in the general case. If available, such ideal observers may turn out to be valuable for imaging system optimization and in the design of computer aided diagnosis techniques for lesion detection in medical images. In this paper, we derive ideal AFROC and FROC observers. They are ideal in that they maximize, amongst all decision strategies, the area, or any partial area, under the associated AFROC or FROC curve. Calculation of observer performance for these ideal observers is computationally quite complex. We can reduce this complexity by considering forms of these observers that use false positive reports derived from signal-absent images only. We also consider a Bayes risk analysis for the multiple-signal detection task with an appropriate definition of costs. A general decision strategy that minimizes Bayes risk is derived. With particular cost constraints, this general decision strategy reduces to the decision strategy associated with the ideal AFROC or FROC observer. PMID:20129845
Quantum lattice gas model of Dirac particles in 1+1 dimensions
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.
A new two-stream instability mode in magnetized quantum plasma
NASA Astrophysics Data System (ADS)
Haas, Fernando; Eliasson, Bengt
2015-08-01
A new transverse mode in a two-stream magnetized quantum plasma is studied by means of a quantum hydrodynamic model, under non-relativistic and ideal Fermi gas assumptions. It is found that Fermi pressure effects induce a minimum cutoff wavelength for instability, unlike the classical case which is unstable for larger wavenumbers. The external magnetic field is also shown to produce a stabilizing effect. Conditions for the applicability of the model and specific parameters for experimental observations are thoroughly discussed.
Quantum Chaos & Quantum Computers
D. L. Shepelyansky
2000-06-15
The standard generic quantum computer model is studied analytically and numerically and the border for emergence of quantum chaos, induced by imperfections and residual inter-qubit couplings, is determined. This phenomenon appears in an isolated quantum computer without any external decoherence. The onset of quantum chaos leads to quantum computer hardware melting, strong quantum entropy growth and destruction of computer operability. The time scales for development of quantum chaos and ergodicity are determined. In spite the fact that this phenomenon is rather dangerous for quantum computing it is shown that the quantum chaos border for inter-qubit coupling is exponentially larger than the energy level spacing between quantum computer eigenstates and drops only linearly with the number of qubits n. As a result the ideal multi-qubit structure of the computer remains rather robust against imperfections. This opens a broad parameter region for a possible realization of quantum computer. The obtained results are related to the recent studies of quantum chaos in such many-body systems as nuclei, complex atoms and molecules, finite Fermi systems and quantum spin glass shards which are also reviewed in the paper.
Goswami, Srijit; Aamir, Mohammed Ali; Shamim, Saquib; Ghosh, Arindam; Siegert, Christoph; Farrer, Ian; Ritchie, David A.; Pepper, Michael
2013-12-04
We use a dual gated device structure to introduce a gate-tuneable periodic potential in a GaAs/AlGaAs two dimensional electron gas (2DEG). Using only a suitable choice of gate voltages we can controllably alter the potential landscape of the bare 2DEG, inducing either a periodic array of antidots or quantum dots. Antidots are artificial scattering centers, and therefore allow for a study of electron dynamics. In particular, we show that the thermovoltage of an antidot lattice is particularly sensitive to the relative positions of the Fermi level and the antidot potential. A quantum dot lattice, on the other hand, provides the opportunity to study correlated electron physics. We find that its current-voltage characteristics display a voltage threshold, as well as a power law scaling, indicative of collective Coulomb blockade in a disordered background.
A MULTIWAVE APPROXIMATE RIEMANN SOLVER FOR IDEAL MHD BASED ON RELAXATION I THEORETICAL FRAMEWORK
for ideal MHD that is an extension of the Suliciu relaxation system for the Euler equations of gas dynamics of state connecting p to # and e. For an ideal gas, p = (# - 1)#e with # > 1, but we consider here a more gas on the other hand, one would still solve (1.1)Â(1.5) with s = cst, except that from the second law
Functoriality of the canonical fractional Galois ideal
Functoriality of the canonical fractional Galois ideal The fractional Galois ideal of [Victor P. Snaith, Stark's conjecture and new Stickelberger phenomena, Canad Galois ideal to arbitrary (possibly infinite and non-abelian) Galois extensions of number fields
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.
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.
NASA Astrophysics Data System (ADS)
Kuze, Nobuhiko; Sakaizumi, Takeshi; Ohashi, Osamu; Yokouchi, Yutaka; Iijima, Kinya
2010-08-01
The gas-phase structure of ( E)-benzaldehyde oxime (C 6H 5sbnd CH dbnd NOH), has been determined by gas-phase electron diffraction (GED), microwave spectroscopy (MW) and quantum-chemical calculations. Two sets of the data analyses were performed. One was GED + MW data analysis with a small-amplitude vibrational model. A planar conformation for this molecule was adopted in the analysis. Another was GED data analysis of a large-amplitude motion of the C sbnd C torsion. The potential minimum was located on the planar conformation of this molecule. Above two sets of the data analyses were led to the one consistent result that showed good agreement between the experimental and calculated molecular intensities.
Effective medium theory of permeation through ideal polymer networks
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.
Taylor, J B
2003-09-12
Ripples in the confining field may exert a torque on a rotating plasma. Time reversal symmetry implies that this torque should vanish for an ideal plasma. However, even in an apparently ideal plasma, singularities can give rise to a nonzero torque. This torque is evaluated for a simple configuration. Although the primary force is magnetic, an essential contribution arises from other nonlinear terms in the equations of motion. The net force is confined to the singular layer, in the direction of the ripple wave vector and related to the energy absorbed in the layer. PMID:14525433
NASA Astrophysics Data System (ADS)
Meier, C.; Beswick, J. A.
2004-09-01
The process of decoherence of vibrational states of I2 in a dense helium environment is studied theoretically using the mixed quantum/classical method based on the Bohmian formulation of quantum mechanics [E. Gindensperger, C. Meier, and J. A. Beswick, J. Chem. Phys. 113, 9369 (2000)]. Specifically, the revival of vibrational wave packets is a quantum phenomena which depends sensitively on the coherence between the vibrational states excited by an ultrafast laser pulse. Its detection by a pump-probe setup as a function of rare gas pressure forms a very accurate way of detecting vibrational dephasing. Vibrational revivals of I2 in high pressure rare gas environments have been observed experimentally, and the very good agreement with the simulated spectra confirms that the method can accurately describe decoherence processes of quantum systems in interaction with an environment.
Failure of the Bell Locality Condition over a Space of Ideal Particles and their Paths
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.
Critical Thinking and Educational Ideal
ERIC Educational Resources Information Center
Liu, Qian
2007-01-01
Critical thinking, as an educational trend, has been much discussed and proposed nowadays. In this paper, an analysis is made on the gap between our present educational practice and educational ideal from three different aspects, that is, the content, the manner and the one-sidedness of our teaching. It's observed that there is still a long way to…
Kucera, Antonin
2007-01-01
We show that there is a low T-upper bound for the class of K-trivial sets, namely those which are weak from the point of view of algorithmic randomness. This result is a special case of a more general characterization of ideals in the T-degrees below 0' for which there is a low T-upper bound.
Antonín Kucera; Theodore A. Slaman
2009-01-01
We show that there is a low T-upper bound for the class of K- trivial sets, namely those which are weak from the point of view of algorithmic randomness. This result is a special case of a more general characterization of ideals in 0 2 T-degrees for which there is a low T-upper bound.
Carbon Nanomaterials: The Ideal Interconnect
's note: Carbon nanotubes and graphene nanoribbons are two promising next- generation interconnectCarbon Nanomaterials: The Ideal Interconnect Technology for Next- Generation ICs Hong Li, Chuan Xu- sectional dimension of copper wires approach their mean free path (about 40 nm at room temperature
Chemical Laws, Idealization and Approximation
ERIC Educational Resources Information Center
Tobin, Emma
2013-01-01
This paper examines the notion of laws in chemistry. Vihalemm ("Found Chem" 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all "ceteris paribus" laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are…
Ideal Eutectic Phase Diagrams Chemistry 243
Ronis, David M.
Ideal Eutectic Phase Diagrams Chemistry 243 David Ronis McGill University The ideal lead immiscible and that the solution was ideal. The liquid- solid coexistence lines are computed from energy for the system (again for ideal solutions and immiscible solids): G = n(s) A Âµ (0) A (solid, T
G IDEALS OF COMPACT SETS SLAWOMIR SOLECKI
Solecki, Slawomir
G IDEALS OF COMPACT SETS SLAWOMIR SOLECKI Abstract. We investigate the structure of G ideals of compact sets. We define a class of G ideals of compact sets that, on the one hand, avoids certain phenomena present among general G ideals of compact sets and, on the other hand, includes all naturally
The Quantum Field Theory of the Ensemble Operator
Porter, Richard N. [Department of Chemistry, State University of New York, Stony Brook, New York, 11794-3400 (United States)
2009-03-09
Quantum field theory (QFT) provides a systematic investigative tool for ensembles of molecules. The grand-canonical ensemble operator (GCEO) for an ideal gas is presented in terms of the Fock creation and annihilation operators. The ideal GCEO can be shown to obey a simple equation which facilitates calculation of quantum-statistical properties of bosonic and fermionic molecules. Examples are linked-cluster QFT derivations of the grand-canonical partition function and the Poisson distribution for non-interacting molecules. The Boltzmann limit is achieved by omitting exchange diagrams. Summations of Feynman diagrams for long- and short-range interactions to infinite order lead to a useful model of the pair-correlation function and a new avenue for the study of dynamics near the critical point for gas-liquid phase transitions.
Positron kinetics in an idealized PET environment
Robson, R. E.; Brunger, M. J.; Buckman, S. J.; Garcia, G.; Petrovi?, Z. Lj.; White, R. D.
2015-01-01
The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the ‘gas-phase’ assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations. PMID:26246002
Positron kinetics in an idealized PET environment
NASA Astrophysics Data System (ADS)
Robson, R. E.; Brunger, M. J.; Buckman, S. J.; Garcia, G.; Petrovi?, Z. Lj.; White, R. D.
2015-08-01
The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the ‘gas-phase’ assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations.
Positron kinetics in an idealized PET environment.
Robson, R E; Brunger, M J; Buckman, S J; Garcia, G; Petrovi?, Z Lj; White, R D
2015-01-01
The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the 'gas-phase' assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations. PMID:26246002
The Gas Sensing Mechanism of the Low-Dimension Carbon Composites with Metal Oxide Quantum Dots
NASA Astrophysics Data System (ADS)
Ma, Hui; Zhou, Weiman; Yuan, Wu; Jie, Zheng; Liu, Hongzhong; Li, Xin.
In this paper, we obtained three kinds of composite materials which were composed of metal oxides (ZnO, SnO2 and TiO2) and CNTs through catalytic pyrolysis method. Then we carried out the surface morphology, field emission and gas sensitivity properties test for them, and summarized the composite ways of metal oxides/CNTs by comparing three composite properties such as the changes in field emission and gas sensing properties, so that we might explore a set of preparation methods and processes of high performance gas sensors. At the same time, the study of field emission can also provide some improved methods to the traditional display technology.
Heterodyne gas cell measurements at 2.9 THz using a quantum cascade laser as local oscillator
NASA Astrophysics Data System (ADS)
Ren, Y.; Gao, J. R.; Hovenier, J. N.; Higgins, R.; Zhang, W.; Bell, A.; Klein, B.; Klapwijk, T. M.; Shi, S. C.; Kao, T.-Y.; Kumar, S.; Hu, Q.; Reno, J. L.
2010-07-01
High-resolution heterodyne spectrometers operating at above 2 THz are crucial for detecting, e.g., the HD line at 2.7 THz and oxygen OI line at 4.7 THz in astronomy. The potential receiver technology is a combination of a hot electron bolometer (HEB) mixer and a THz quantum cascade laser (QCL) local oscillator (LO).Here we report the first highresolution heterodyne spectroscopy measurement of a gas cell using such a HEB-QCL receiver. The receiver employs a 2.9 THz free-running QCL as local oscillator and a NbN HEB as a mixer. By using methanol (CH3OH) gas as a signal source, we successfully recorded the methanol emission line at 2.92195 THz. Spectral lines at IF frequency at different pressures were measured using a FFTS and well fitted with a Lorentzian profile. Our gas cell measurement is a crucial demonstration of the QCL as LO for practical heterodyne instruments. Together with our other experimental demonstrations, such as using a QCL at 70 K to operate a HEB mixer and the phase locking of a QCL such a receiver is in principle ready for a next step, which is to build a real instrument for any balloon-, air-, and space-borne observatory.
Dicke quantum phase transition with a superfluid gas in an optical cavity.
Baumann, Kristian; Guerlin, Christine; Brennecke, Ferdinand; Esslinger, Tilman
2010-04-29
A phase transition describes the sudden change of state of a physical system, such as melting or freezing. Quantum gases provide the opportunity to establish a direct link between experiments and generic models that capture the underlying physics. The Dicke model describes a collective matter-light interaction and has been predicted to show an intriguing quantum phase transition. Here we realize the Dicke quantum phase transition in an open system formed by a Bose-Einstein condensate coupled to an optical cavity, and observe the emergence of a self-organized supersolid phase. The phase transition is driven by infinitely long-range interactions between the condensed atoms, induced by two-photon processes involving the cavity mode and a pump field. We show that the phase transition is described by the Dicke Hamiltonian, including counter-rotating coupling terms, and that the supersolid phase is associated with a spontaneously broken spatial symmetry. The boundary of the phase transition is mapped out in quantitative agreement with the Dicke model. Our results should facilitate studies of quantum gases with long-range interactions and provide access to novel quantum phases. PMID:20428162
M. Bahrami ENSC 461 (S 11) Jet Propulsion Cycle 1 Ideal JetPropulsion Cycle
Bahrami, Majid
. Aircraft gas turbines operate on an open cycle called jet-propulsion cycle. Some of the major differences that the gas undergoes provides a thrust to the aircraft the fluid passes through a diffuser first whereM. Bahrami ENSC 461 (S 11) Jet Propulsion Cycle 1 Ideal JetPropulsion Cycle Gas-turbine engines
Computational chemistry, in conjunction with gas chromatography/mass spectrometry/Fourier transform infrared spectrometry (GC/MS/FT-IR), was used to tentatively identify seven tetrachlorobutadiene (TCBD) isomers detected in an environmental sample. Computation of the TCBD infrare...
Dynamics of correlations in a quasi-2D dipolar Bose gas following a quantum quench
Stefan S. Natu; L. Campanello; S. Das Sarma
2014-10-17
We study the evolution of correlations in a quasi-2D dipolar gas driven out-of-equilibrium by a sudden ramp of the interaction strength. For sufficiently strong ramps, the momentum distribution, excited fraction and density-density correlation function all display pronounced features that are directly related to the appearance of a roton minimum in the underlying spectrum. Our study suggests that the evolution of correlations following a quench can be used as a probe of roton-like excitations in a dipolar gas. We also find that the build up of density-density correlations following a quench occurs much more slowly in the dipolar gas compared to a non-dipolar gas, owing to the long-range interactions.
Cylindrical magnets and ideal solenoids
NASA Astrophysics Data System (ADS)
Derby, Norman; Olbert, Stanislaw
2010-03-01
Both wire-wound solenoids and cylindrical magnets can be approximated as ideal azimuthally symmetric solenoids. We present an exact solution for the magnetic field of an ideal solenoid in an easy to use form. The field is expressed in terms of a single function that can be rapidly computed by means of a compact efficient algorithm, which can be coded as an add-in function to a spreadsheet, making field calculations accessible to introductory students. These expressions are not only accurate but are also as fast as most approximate expressions. We demonstrate their utility by simulating the dropping of a cylindrical magnet through a nonmagnetic conducting tube and comparing the calculation with data obtained from experiments suitable for an undergraduate laboratory.
Modules over principal ideal rings
Vieaux, Jules Bellin
1957-01-01
(PIP2P3) and by Lemms. I ~ 6, this chain must terminate with some ideal (plp2p3. . . p ). Thus a = bplp2p3 ~ . , p where b is a unit ~ r I 2'3 r To show that the representation for a is unique, 1st ( I) = plp2. . . p ? qlq2. ~ . q ' be two..., 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 l5 Il. NODULES DEFINITION 2. 1. A left module 1s a commutative group M...
IDEMPOTENT IDEALS THE TRANSFINITE RADICAL TELESCOPE CONJECTURE Idempotent ideals in a module IDEALS THE TRANSFINITE RADICAL TELESCOPE CONJECTURE Definition Let C be a skeletally small additive category. A (2-sided) ideal I of C is a collection of morphisms such that: #12;IDEMPOTENT IDEALS
Performance evaluation of TCP connections in ideal and non-ideal network environments
ElAarag, Hala
Performance evaluation of TCP connections in ideal and non-ideal network environments Hala El In this paper, we study the performance of TCP in both ideal and non-ideal network environments. For the ideal environments, we develop a simple analytical model for the throughput and transfer time of TCP as a function
Quantum-tunneling dynamics of a spin-polarized Fermi gas in a double-well potential
Salasnich, L.; Mazzarella, G.; Toigo, F. [Dipartimento di Fisica 'Galileo Galilei' and CNISM, Universita di Padova, Via Marzolo 8, I-35122 Padua (Italy); Salerno, M. [Dipartimento di Fisica 'E.R. Caianiello', CNISM and INFN-Gruppo Collegato di Salerno, Universita di Salerno, Via Ponte don Melillo, I-84084 Fisciano(Italy)
2010-02-15
We study the exact dynamics of a one-dimensional spin-polarized gas of fermions in a double-well potential at zero and finite temperature. Despite the system being made of noninteracting fermions, its dynamics can be quite complex, showing strongly aperiodic spatio-temporal patterns during the tunneling. The extension of these results to the case of mixtures of spin-polarized fermions interacting with self-trapped Bose-Einstein condensates (BECs) at zero temperature is considered as well. In this case we show that the fermionic dynamics remains qualitatively similar to that observed in the absence of BEC but with the Rabi frequencies of fermionic excited states explicitly depending on the number of bosons and on the boson-fermion interaction strength. From this, the possibility of controlling quantum fermionic dynamics by means of Feshbach resonances is suggested.
An Alternative Derivation of Gas Pressure Using the Kinetic Theory Frank Rioux
Rioux, Frank
Carpenter pointed out many years ago (2), it is through a comparison of equation (5) with the ideal gas law theory is used to derive the pressure of an ideal gas assuming that the gas occupies a spherical to derive the pressure of an ideal gas do so by studying a gas in a cubic or rectangular container (1
Perpetual motion of a mobile impurity in a one-dimensional quantum gas
Oleg Lychkovskiy
2014-03-04
Consider an impurity particle injected in a degenerate one-dimensional gas of noninteracting fermions (or, equivalently, Tonks-Girardeau bosons) with some initial momentum $p_0$. We examine the infinite-time value of the momentum of the impurity, $p_\\infty$, as a function of $p_0$. A lower bound on $|p_\\infty(p_0)|$ is derived under fairly general conditions. The derivation, based on the existence of the lower edge of the spectrum of the host gas, does not resort to any approximations. The existence of such bound implies the perpetual motion of an impurity in a one-dimensional gas of noninteracting fermions or Tonks-Girardeau bosons at zero temperature. The bound has an especially simple and useful form when the interaction between the impurity and host particles is everywhere repulsive.
Perpetual motion of a mobile impurity in a one-dimensional quantum gas
NASA Astrophysics Data System (ADS)
Lychkovskiy, O.
2014-03-01
Consider an impurity particle injected in a degenerate one-dimensional gas of noninteracting fermions (or, equivalently, Tonks-Girardeau bosons) with some initial momentum p0. We examine the infinite-time value of the momentum of the impurity, p?, as a function of p0. A lower bound on |p?(p0)| is derived under fairly general conditions. The derivation, based on the existence of the lower edge of the spectrum of the host gas, does not resort to any approximations. The existence of such bound implies the perpetual motion of the impurity in a one-dimensional gas of noninteracting fermions or Tonks-Girardeau bosons at zero temperature. The bound admits an especially simple and useful form when the interaction between the impurity and host particles is everywhere repulsive.
Borisov, A. G. [Laboratoire des Collisions Atomiques et Moleculaires (CNRS UMR 8625), Batiment 351, Universite Paris-Sud, 91405 Orsay Cedex (France); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Juaristi, J. I. [Departamento de Fisica de Materiales, Facultad de Quimicas UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain); Unidad de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU, P. Manuel de Lardizabal 3, 20018 San Sebastian (Spain); Muino, R. Diez; Sanchez-Portal, D. [Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Unidad de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU, P. Manuel de Lardizabal 3, 20018 San Sebastian (Spain); Echenique, P. M. [Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Facultad de Quimicas UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain); Unidad de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU, P. Manuel de Lardizabal 3, 20018 San Sebastian (Spain)
2006-01-15
Time-dependent density-functional theory is used to calculate quantum-size effects in the energy loss of antiprotons interacting with a confined two-dimensional electron gas. The antiprotons follow a trajectory normal to jellium circular clusters of variable size, crossing every cluster at its geometrical center. Analysis of the characteristic time scales that define the process is made. For high-enough velocities, the interaction time between the projectile and the target electrons is shorter than the time needed for the density excitation to travel along the cluster. The finite-size object then behaves as an infinite system, and no quantum-size effects appear in the energy loss. For small velocities, the discretization of levels in the cluster plays a role and the energy loss does depend on the system size. A comparison to results obtained using linear theory of screening is made, and the relative contributions of electron-hole pair and plasmon excitations to the total energy loss are analyzed. This comparison also allows us to show the importance of a nonlinear treatment of the screening in the interaction process.
NASA Astrophysics Data System (ADS)
Kormann, R.; Königstedt, R.; Parchatka, U.; Lelieveld, J.; Fischer, H.
2005-07-01
We describe QUALITAS, a mid-infrared spectrometer with multipass absorption cell, suitable to apply lead chalcogenide and quantum cascade lasers as light sources in CW operation at cryogenic temperatures. The instrument has been designed for the measurement of trace gases such as carbon monoxide, nitrous oxide or methane in the clean atmosphere from space-restricted and experimentally challenging mobile platforms. The design involves compact optics, which fit into the space limitations of a standard aircraft borne 19in. rack (W×H×D?48×45×40cm3). The instrument allows high sensitivity (?5×10-7m-1Hz-1/2 during flight; ?1×10-7m-1Hz-1/2 in the laboratory) in combination with a low sample gas volume (0.3L) for high time resolution (<1s, using a moderately sized pump). We employ a combination of elements already applied in former spectrometers in our laboratory and a novel arrangement of spherical mirrors. The design criteria, the optical, electronic and mechanical set-up are described in detail. The application of the instrument to measure atmospheric concentrations of carbon monoxide is discussed, using both, a lead chalcogenide as well as a DFB-structured quantum cascade laser (R3 line at 2158.3cm-1).
Rheology of nearly ideal 3d foams
C. D. Jones; K. N. Nordstrom; D. J. Durian
2014-04-10
We probe the complex rheology of nearly ideal 3d foam by flowing through a narrow column. The foams we investigate have large bubble size, to minimize the effects of coarsening, and are very dry. Foams of this type cannot be studied via conventional rheometry. The foam flows upward through a vertical rectangular column with a 4:1 cross-sectional aspect ratio, by bubbling gas through a soapy solution at the base of our apparatus. At the column's narrow surfaces are sticky boundaries, which create shear due to the zero velocity boundary condition. As expected, the flow profile between the adjacent slippery broad faces is flat, however the profile between the narrow, sticky faces exhibits a curved velocity profile that is dependent on gas flow rate. We are able to analyze a 2d velocity profile from a 3d bulk system. We employ particle image velocimetry to measure the strain rate, and compute the stress from the pressure drop along the channel, to investigate the local stress-strain relationships in a flowing foam. We find these dry foams to have a Hershel-Bulkley exponent of 0.21, which is significantly lower (more shear thinning) than other results shown in the literature for much wetter foams.
Quantum oscillations in a two-dimensional electron gas in black phosphorus thin films
NASA Astrophysics Data System (ADS)
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.
Magnetoresistance quantum oscillations in a magnetic two-dimensional electron gas
NASA Astrophysics Data System (ADS)
Kunc, J.; Piot, B. A.; Maude, D. K.; Potemski, M.; Grill, R.; Betthausen, C.; Weiss, D.; Kolkovsky, V.; Karczewski, G.; Wojtowicz, T.
2015-08-01
Magnetotransport measurements of Shubnikov-de Haas (SdH) oscillations have been performed on two-dimensional electron gases (2DEGs) confined in CdTe and CdMnTe quantum wells. The quantum oscillations in CdMnTe, where the 2DEG interacts with magnetic Mn ions, can be described by incorporating the electron-Mn exchange interaction into the traditional Lifshitz-Kosevich formalism. The modified spin splitting leads to characteristic beating pattern in the SdH oscillations, the study of which indicates the formation of Mn clusters resulting in direct anti-ferromagnetic Mn-Mn interaction. The Landau-level broadening in this system shows a peculiar decrease with increasing temperature, which could be related to statistical fluctuations of the Mn concentration.
Critical points in a relativistic bosonic gas induced by the quantum structure of spacetime
Castellanos, Elias
2008-01-01
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 particle has been considered.
Fermi one-dimensional quantum gas: Luttinger liquid approach and spin-charge separation
A. Recati; P. O. Fedichev; W. Zwerger; P. Zoller
2003-01-01
We discuss the properties of quasi-one-dimensional quantum gases of fermionic atoms using the Luttinger liquid theory, including the presence of an optical lattice and of a longitudinal trapping potential. We analyse in particular the nature and manifestations of spin-charge separation, where in the case of atoms 'spin' and 'charge' refers to two internal atomic states and the atomic mass density,
Fermi 1D quantum gas: Luttinger liquid approach and spin-charge separation
A. Recati; P. O. Fedichev; W. Zwerger; P. Zoller
2002-12-09
We discuss the properties of quasi-1D quantum gases of fermionic atoms using the Luttinger liquid theory, including the presence of an optical lattice and of a longitudinal trapping potential. We analyze in particular the nature and manifestations of spin-charge separation, where in the case of atoms ``spin'' and ``charge'' refers to two internal atomic states and the atomic mass density, respectively.
Fermi 1D quantum gas: Luttinger liquid approach and spin-charge separation
A. Recati; P. O. Fedichev; W. Zwerger; P. Zoller
2002-01-01
We discuss the properties of quasi-1D quantum gases of fermionic atoms using\\u000athe Luttinger liquid theory, including the presence of an optical lattice and\\u000aof a longitudinal trapping potential. We analyze in particular the nature and\\u000amanifestations of spin-charge separation, where in the case of atoms ``spin''\\u000aand ``charge'' refers to two internal atomic states and the atomic mass\\u000adensity,
Detonation Failure in Ideal and Non-Ideal Explosives
NASA Astrophysics Data System (ADS)
Haskins, P. J.; Cook, M. D.
2007-06-01
In this paper we revisit and extend the classic treatment of detonation failure developed by Eyring et. al. [1]. We recently published a development of this theory [2] in which a pressure dependant rate law was substituted for the Arrhenius temperature dependant law originally considered. Here we show that by assuming a 2-component rate law based upon a temperature dependant ignition phase and a pressure dependant growth phase we are able to rationalise the very different failure characteristics (critical diameter and velocity decrement at failure) of ideal and non-ideal explosives. [1] Eyring, H., Powell, R.E., Duffy, G.H., and Parlin, R.B., ``The stability of detonation,'' Chem. Rev. 45, 69-181 (1949). [2] Haskins, P.J., Cook, M.D., and Wood, A.D., ``On the dependence of critical diameter and velocity decrement at failure on the burn law,'' in proceedings of the 33rd International Pyrotechnics Seminar, Fort Collins, Co, USA, 385-391 (2006).
On the Splitting of a Quantum Degenerate Gas of Identical Bosons
NASA Astrophysics Data System (ADS)
Faust, Douglas Karl
2011-12-01
The observation of Bose-Einstein condensation in dilute clouds of trapped atoms has stimulated a great deal of research in the last 15 years. Since the basic description of a single Bose-Einstein condensate (BEC) is that of a single macroscopic condensate wavefunction, or condensate order parameter, which displays all of the interference and non-local phenomena associated with the typical quantum mechanical wavefunction, yet describes up to millions of particles, these systems have the potential to bridge the quantum mechanical and visible classical worlds. Many basic scientific questions can be addressed by examining what happens when a single such system is split into multiple entities, independently manipulated and then recombined as has been done experimentally in the case of two potential welts [1] and many potential wells [2], [3]. This thesis shows that these experiments can operate in both a classical and quantum mechanical splitting regime and demarcates the boundary in between the two. By analyzing two specific BEC splitting experiments, it is shown that splitting experiments operating in the limit of a large number of particles per well can exhibit a phenomenon analogous to supercooling in classical phase transitions. In order to perform these simulations, a novel method, extending earlier theoretical work on the splitting problem is presented, computationally implemented, and supported by analytic calculations when possible.
Efficient Parallel Computing for Laser-Gas Quantum Interaction and Propagation
Lorin, Emmanuel
the propagation of an electro-magnetic field in a gas modeled by many Time Dependent Schr¨odinger Equations (TDSE 10-14 second), intense (more than 1013 W · cm-2 ) and high frequency (less than 800 nm) laser pulses
A Quantum Chemistry Study of Natural Gas Hydrates Mert Atilhan,1
Pala, Nezih
clathrate compounds, are crystalline inclusion compounds formed when a small gas molecule (e.g. methane reservoirs.1,2,3 Methane present in hydrates is considered as a very attractive new source of energy requiring new technologies to exploit them.4 Likewise, methane hydrates may also considered as global
NASA Astrophysics Data System (ADS)
Rota, R.; Tramonto, F.; Galli, D. E.; Giorgini, S.
2013-12-01
We investigate the dynamic structure factor of a system of Bose particles at zero temperature using quantum Monte Carlo methods. Interactions are modeled using a hard-sphere potential of size a and simulations are performed for values of the gas parameter na3 ranging from the dilute regime up to densities n where the thermodynamically stable phase is a solid. With increasing density, we observe a crossover of the dispersion of elementary excitations from a Bogoliubov-type spectrum to a phonon-maxon-roton curve and the emergence of a broad multiphonon contribution accompanying the single-quasiparticle peak. In particular, for na3=0.2138, which corresponds to superfluid 4He at equilibrium density, the extracted spectrum turns out to be in good agreement with the experimental energy-momentum dispersion relation in the roton region and for higher momenta. The behavior of the spectral function at the same density in the stable solid and metastable gas phase above the freezing point is also discussed.
Chemical Laws, Idealization and Approximation
NASA Astrophysics Data System (ADS)
Tobin, Emma
2013-07-01
This paper examines the notion of laws in chemistry. Vihalemm ( Found Chem 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all ceteris paribus laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are fundamentally different to the laws of physics, because they involve approximations. Christie ( Stud Hist Philos Sci 25:613-629, 1994) and Christie and Christie ( Of minds and molecules. Oxford University Press, New York, pp. 34-50, 2000) agree that the laws of chemistry are operationally different to the laws of physics, but claim that the distinction between exact and approximate laws is too simplistic to taxonomise them. Approximations in chemistry involve diverse kinds of activity and often what counts as a scientific law in chemistry is dictated by the context of its use in scientific practice. This paper addresses the question of what makes chemical laws distinctive independently of the separate question as to how they are related to the laws of physics. From an analysis of some candidate ceteris paribus laws in chemistry, this paper argues that there are two distinct kinds of ceteris paribus laws in chemistry; idealized and approximate chemical laws. Thus, while Christie ( Stud Hist Philos Sci 25:613-629, 1994) and Christie and Christie ( Of minds and molecules. Oxford University Press, New York, pp. 34--50, 2000) are correct to point out that the candidate generalisations in chemistry are diverse and heterogeneous, a distinction between idealizations and approximations can nevertheless be used to successfully taxonomise them.
Nearly ideal lens optimization procedure
Brixner, B.
1985-01-01
The Brixner lens optimization procedure, in which a lens design moves steadily toward diffraction-limited performance, samples lens performance with bundles of precisely traced skew rays, analyzes performance by calculating the image-spot sizes and positions, and optimizes performance in a least squares system that minimizes the lateral ray deviations from their ideal image points. Minimizing the rms image-spot size minimizes the rms optical path differences (OPDs). Minimizing the rms OPDs also optimizes the diffraction modulation transfer function (DMTF). Minimizing the image-spot size and position errors also minimizes and balances the Seidel and higher-order aberrations. 23 refs., 2 figs.
(Fuzzy) Ideals of BN-Algebras.
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
The Ideal Self and State Authenticity
Power, Katherine Emilia
2011-11-23
The current study investigated the effect of priming people with alignment or distance to ideal self attributes on their feelings of authenticity. The effect of priming participants with self-irrelevant alignment or distance to ideal attributes...
On the Learnability of Shuffle Ideals
Eisenstat, Sarah Charmian
PAC learning of unrestricted regular languages is long known to be a difficult problem. The class of shuffle ideals is a very restricted subclass of regular languages, where the shuffle ideal generated by a string u is the ...
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
Loss, Daniel
correlated2 source of atoms that allows us to observe n-body correlations up to the sixth- order at the ideal pivotal in the establishment of the field of quantum optics. Importantly, the definition of a coher- ent including astronomy6 , particle physics7 , quantum optics8 , and quantum atom optics9 . In particular
UNIQUE IRREDUNDANT INTERSECTIONS OF COMPLETELY IRREDUCIBLE IDEALS
Heinzer, William
UNIQUE IRREDUNDANT INTERSECTIONS OF COMPLETELY IRREDUCIBLE IDEALS WILLIAM HEINZER AND BRUCE OLBERDING Abstract. An ideal of a commutative ring is completely irreducible if it is not the intersection of any set of proper overideals. It is known that every ideal is an intersection of completely
FAITHFUL IDEAL MODELS FOR RECURSIVE POLYMORPHIC TYPES
Plotkin, Gordon
FAITHFUL IDEAL MODELS FOR RECURSIVE POLYMORPHIC TYPES MARTÂ´IN ABADI Digital Equipment Corporation of Computer Science King's Building University of Edinburgh Edinburgh, EH9 3JZ, UK ABSTRACT We explore idealQueen, Plotkin, and Sethi. The use of suitable ideals yields a close fit between models and programming language
Identifying Ideal Lattices Jintai Ding1
International Association for Cryptologic Research (IACR)
Identifying Ideal Lattices Jintai Ding1 and Richard Lindner2 1 University of Cincinnati, Department@cdc.informatik.tu-darmstadt.de Abstract. Micciancio defined a generalization of cyclic lattices, called ideal lattices. These lattices can. This provable se- curity relies on the assumption that reducing bases of ideal lattices is similar to reducing
Characterizing integral domains by semigroups of ideals
Fontana, Marco
Characterizing integral domains by semigroups of ideals Stefania Gabelli Notes for an advanced course in Ideal Theory a. a. 2009-2010 1 #12;Contents 1 Star operations 4 1.1 The v-operation and the t . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.5 t-invertible t-prime ideals . . . . . . . . . . . . . . . . . . . . 13 2 Relevant classes
A Saturation Algorithm for Homogeneous Binomial Ideals
Mehta, Shashank K
A Saturation Algorithm for Homogeneous Binomial Ideals Deepanjan Kesh and Shashank K Mehta Indian, . . . , xn] be a polynomial ring in n variables, and let I k[x1, . . . , xn] be a homogeneous binomial ideal I is a toric ideal, we present some preliminary results comparing our algorithm with Project
A study on ideal ward continuity
Huseyin Cakalli
2013-12-05
In this paper, we prove that any ideal ward continuous function is uniformly continuous either on an interval or on an ideal ward compact subset of $\\textbf{R}$. A characterization of uniform continuity is also given via ideal quasi-Cauchy sequences.
Recharging Our Sense of Idealism: Concluding Thoughts
ERIC Educational Resources Information Center
D'Andrea, Michael; Dollarhide, Colette T.
2011-01-01
In this article, the authors aim to recharge one's sense of idealism. They argue that idealism is the Vitamin C that sustains one's commitment to implementing humanistic principles and social justice practices in the work of counselors and educators. The idealism that characterizes counselors and educators who are humanistic and social justice…
ERIC Educational Resources Information Center
Holko, David A.
1982-01-01
Presents a complete computer program demonstrating the relationship between volume/pressure for Boyle's Law, volume/temperature for Charles' Law, and volume/moles of gas for Avagadro's Law. The programing reinforces students' application of gas laws and equates a simulated moving piston to theoretical values derived using the ideal gas law.…
Life's Solutions are Not Ideal
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.
Representation of ideal magnetohydrodynamic modes
White, R. B.
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.
The quantum mechanics of ion-enhanced field emission and how it influences microscale gas breakdown
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.
Hair, S.R.; Beswick, J.A.; Janda, K.C.
1988-10-01
An approximate description of the van der Waals vibrations of ethylene dimer and rare gas--ethylene complexes is presented. Using a model atom--atom potential, this calculation examines the mixing of the ethylene ..nu../sub 7/ vibration with a set of background vibrational levels, consisting of combinations of the van der Waals vibrations and the ethylene ..nu../sub 10/ vibration. The ethylene dimer exhibits extensive vibrational mixing, while the rare gas--ethylene molecules do not. For the ethylene dimer, calculated line strengths produce a complex spectrum of vibrational lines that span a 10 cm/sup -1/ region, in agreement with the experimental spectrum. This result suggests new explanations for the coexistence of broad and narrow lines in the ethylene dimer ..nu../sub 7/ dissociation spectrum.
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.
Finite-temperature quantum Monte Carlo study of the one-dimensional polarized Fermi gas
Wolak, M. J. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Rousseau, V. G. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Miniatura, C. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, F-06560 Valbonne (France); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Gremaud, B. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Scalettar, R. T. [Physics Department, University of California, Davis, California 95616 (United States); Batrouni, G. G. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, F-06560 Valbonne (France)
2010-07-15
Quantum Monte Carlo (QMC) techniques are used to provide an approximation-free investigation of the phases of the one-dimensional attractive Hubbard Hamiltonian in the presence of population imbalance. The temperature at which the ''Fulde-Ferrell-Larkin-Ovchinnikov'' (FFLO) phase is destroyed by thermal fluctuations is determined as a function of the polarization. It is shown that the presence of a confining potential does not dramatically alter the FFLO regime and that recent experiments on trapped atomic gases likely lie just within the stable temperature range.
Statistical mechanics based on fractional classical and quantum mechanics
Korichi, Z.; Meftah, M. T.
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.
NASA Astrophysics Data System (ADS)
Nieuwenhuizen, Theo M.; Mehmani, Bahar; Špi?ka, Václav; Aghdami, Maryam J.; Khrennikov, Andrei Yu
2007-09-01
pt. A. Introductions. The mathematical basis for deterministic quantum mechanics / G.'t Hooft. What did we learn from quantum gravity? / A. Ashtekar. Bose-Einstein condensates and EPR quantum non-locality / F. Laloe. The quantum measurement process: lessons from an exactly solvable model / A.E. Allahverdyan, R. Balian and Th. M. Nieuwenhuizen -- pt. B. Quantum mechanics and quantum information. POVMs: a small but important step beyond standard quantum mechanics / W. M. de Muynck. State reduction by measurements with a null result / G. Nienhuis. Solving open questions in the Bose-Einstein condensation of an ideal gas via a hybrid mixture of laser and statistical physics / M. Kim, A. Svidzinsky and M.O. Scully. Twin-Photon light scattering and causality / G. Puentes, A. Aiello and J. P. Woerdman. Simultaneous measurement of non-commuting observables / G. Aquino and B. Mehmani. Quantum decoherence and gravitational waves / M.T. Jaekel ... [et al.]. Role of various entropies in the black hole information loss problem / Th. M. Nieuwenhuizen and I.V. Volovich. Quantum and super-quantum correlations / G.S. Jaeger -- pt. C. Long distance correlations and bell inequalities. Understanding long-distance quantum correlations / L. Marchildon. Connection of probability models to EPR experiments: probability spaces and Bell's theorem / K. Hess and W. Philipp. Fair sampling vs no-signalling principle in EPR experiments / G. Adenier and A. Yu. Khrennikov -- pt. D. Mathematical foundations. Where the mathematical structure of quantum mechanics comes from / G.M. D'Ariano. Phase space description of quantum mechanics and non-commutative geometry: Wigner-Moyal and Bohm in a wider context / B.J. Hiley. Quantum mechanics as simple algorithm for approximation of classical integrals / A. Yu. Khrennikov. Noncommutative quantum mechanics viewed from Feynman Formalism / J. Lages ... [et al.]. Beyond the quantum in Snyder space / J.F.S. van Huele and M. K. Transtrum -- pt. E. Stochastic electrodynamics. Some quantum experiments from the point of view of Stochastic electrodynamics / V. Spicka ... [et al.]. On the ergodic behaviour of atomic systems under the action of the zero-point radiation field / L. De La Peña and A. M. Cetto. Inertia and the vacuum-view on the emergence of the inertia reaction force / A. Rueda and H. Sunahata -- pt. F. Models for the electron. Rotating Hopf-Kinks: oscillators in the sense of de Broglie / U. Enz. Kerr-Newman particles: symmetries and other properties / H.I. Arcos and J.G. Pereira. Kerr geometry beyond the quantum theory / Th. M. Nieuwenhuizen -- pt. G. Philosophical considerations. Probability in non-collapse interpretations of a quantum mechanics / D. Dieks. The Schrödinger-Park paradox about the concept of "State" in quantum statistical mechanics and quantum information theory is still open: one more reason to go beyond? / G.P. Beretta. The conjecture that local realism is possible / E. Santos -- pt. H. The round table. Round table discussion / A.M. Cetto ... [et al.].
Vortex in a weakly relativistic Bose gas at zero temperature and relativistic fluid approximation
B. Boisseau
2004-09-14
The Bogoliubov procedure in quantum field theory is used to describe a relativistic almost ideal Bose gas at zero temperature. Special attention is given to the study of a vortex. The radius of the vortex in the field description is compared to that obtained in the relativistic fluid approximation. The Kelvin waves are studied and, for long wavelengths, the dispersion relation is obtained by an asymptotic matching method and compared with the non relativistic result.
Quantum field theory for the three-body constrained lattice Bose gas. I. Formal developments
Diehl, S.; Daley, A. J.; Zoller, P. [Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Baranov, M. [Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); RRC 'Kurchatov Institute', Kurchatov Square 1, 123182 Moscow (Russian Federation)
2010-08-01
We develop a quantum field theoretical framework to analytically study the three-body constrained Bose-Hubbard model beyond mean field and noninteracting spin wave approximations. It is based on an exact mapping of the constrained model to a theory with two coupled bosonic degrees of freedom with polynomial interactions, which have a natural interpretation as single particles and two-particle states. The procedure can be seen as a proper quantization of the Gutzwiller mean field theory. The theory is conveniently evaluated in the framework of the quantum effective action, for which the usual symmetry principles are now supplemented with a ''constraint principle'' operative on short distances. We test the theory via investigation of scattering properties of few particles in the limit of vanishing density, and we address the complementary problem in the limit of maximum filling, where the low-lying excitations are holes and diholes on top of the constraint-induced insulator. This is the first of a sequence of two papers. The application of the formalism to the many-body problem, which can be realized with atoms in optical lattices with strong three-body loss, is performed in a related work [S. Diehl, M. Baranov, A. Daley, and P. Zoller, Phys. Rev. B 82, 064510 (2010)].
Quantum oscillations in a two-dimensional electron gas in black phosphorus thin films.
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
Modified Coulomb gas construction of quantum Hall states from nonunitary conformal field theories
Milovanovic, M. V.; Vidanovic, I. [Institute of Physics, P.O. Box 68, 11080 Belgrade (Serbia); Jolicoeur, Th. [Laboratoire de Physique Theorique et Modeles Statistiques, Universite Paris-Sud, 91405 Orsay (France)
2009-10-15
Some fractional quantum Hall states observed in experiments may be described by first-quantized wavefunctions with special clustering properties such as the Moore-Read Pfaffian for filling factor {nu}=5/2. This wavefunction has been constructed by constructing correlation functions of a two-dimensional conformal field theory (CFT) involving a free boson and a Majorana fermion. By considering other CFTs many other clustered states have been proposed as candidate fractional quantum Hall states under appropriate circumstances. It is believed that the underlying CFT should be unitary if one wants to describe an incompressible, i.e., gapped liquid state. We show that by changing the way one derives the wavefunction from its parent CFT it is possible to obtain an incompressible candidate state when starting from a nonunitary parent. The construction mimics a global change in parameters in the phase space of the electron system. We explicit our construction in the case of the so-called Gaffnian state (a state for filling factor 2/5) and also for the Haldane-Rezayi state (a spin-singlet state at filling 1/2). We note that there are obstructions along this path in the case of the permanent spin-singlet state of Read and Rezayi which can be characterized as a robust gapless state.
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.
Computational Methods for Ideal Magnetohydrodynamics
NASA Astrophysics Data System (ADS)
Kercher, Andrew D.
Numerical schemes for the ideal magnetohydrodynamics (MHD) are widely used for modeling space weather and astrophysical flows. They are designed to resolve the different waves that propagate through a magnetohydro fluid, namely, the fast, Alfven, slow, and entropy waves. Numerical schemes for ideal magnetohydrodynamics that are based on the standard finite volume (FV) discretization exhibit pseudo-convergence in which non-regular waves no longer exist only after heavy grid refinement. A method is described for obtaining solutions for coplanar and near coplanar cases that consist of only regular waves, independent of grid refinement. The method, referred to as Compound Wave Modification (CWM), involves removing the flux associated with non-regular structures and can be used for simulations in two- and three-dimensions because it does not require explicitly tracking an Alfven wave. For a near coplanar case, and for grids with 213 points or less, we find root-mean-square-errors (RMSEs) that are as much as 6 times smaller. For the coplanar case, in which non-regular structures will exist at all levels of grid refinement for standard FV schemes, the RMSE is as much as 25 times smaller. A multidimensional ideal MHD code has been implemented for simulations on graphics processing units (GPUs). Performance measurements were conducted for both the NVIDIA GeForce GTX Titan and Intel Xeon E5645 processor. The GPU is shown to perform one to two orders of magnitude greater than the CPU when using a single core, and two to three times greater than when run in parallel with OpenMP. Performance comparisons are made for two methods of storing data on the GPU. The first approach stores data as an Array of Structures (AoS), e.g., a point coordinate array of size 3 x n is iterated over. The second approach stores data as a Structure of Arrays (SoA), e.g. three separate arrays of size n are iterated over simultaneously. For an AoS, coalescing does not occur, reducing memory efficiency. All results are given for Cartesian grids, but the algorithms are implemented for a general geometry on a unstructured grids.
On Fuzzy Bi-ideals and Fuzzy Quasi Ideals in Gamma-Semigroups
Sujit Kumar Sardar; Samit Kumar Majumder; Soumitra Kayal
2011-01-25
The purpose of this paper is to investigate some properties of fuzzy ideals and fuzzy bi-ideals in gamma-semigroups and to introduce the notion of fuzzy quasi ideals in gamma-semigroups. Here we also characterize a regular gamma-semigroup in terms of fuzzy quasi ideals.
ON THE DISTRIBUTION OF PRIME IDEALS WITHIN THE IDEAL CLASS GROUP
ON THE DISTRIBUTION OF PRIME IDEALS WITHIN THE IDEAL CLASS GROUP Robert Gilmer, William Heinzer a Dedekind domain D with class group K such that, for each k in K, exactly \\Delta(k) maximal ideals of D for a nonidentity element k of K to contain exactly one maximal ideal of D? We show in Example 6 that (Q) has
THE MULTIPLIER IDEAL IS A UNIVERSAL TEST IDEAL Karen E. Smith \\Lambda
Smith, Karen E.
THE MULTIPLIER IDEAL IS A UNIVERSAL TEST IDEAL Karen E. Smith \\Lambda Dedicated to Professor Robin Hartshorne on the occasion of his sixtieth birthday 1. Introduction Two different ideals have been defined algebra, the test ideal defined by Hochster and Huneke [HH1] plays a central role in the theory of tight
Diameter effect and detonation front curvature of ideal and non-ideal explosives
NASA Astrophysics Data System (ADS)
Sandstrom, F. W.; Abernathy, R. L.; Leone, M. G.; Banks, M. L.
2000-04-01
Diameter effect and detonation front curvature data are presented for several representative ideal and non-ideal explosives, including cast TNT, Tritonal, urea nitrate (UN), ANFO, and two variants of ammonium nitrate (AN)/solid fuel explosives. The ideal vs. non-ideal detonation characteristics of these various explosives are compared and contrasted with respect to particle size and chemical composition.
Irreversibility in an ideal fluid
Jenkins, Alejandro
2013-01-01
When a real fluid is expelled quickly from a tube, it forms a jet separated from the surrounding fluid by a thin, turbulent layer. On the other hand, when the same fluid is sucked into the tube, it comes in from all directions, forming a sink-like flow. We show that, even for the ideal flow described by the time-reversible Euler equation, an experimenter who only controls the pressure in a pump attached to the tube would see jets form in one direction exclusively. The asymmetry between outflow and inflow therefore does not depend on viscous dissipation, but rather on the experimenter's limited control of initial and boundary conditions. This illustrates, in a rather different context from the usual one of thermal physics, how irreversibility may arise in systems whose microscopic dynamics are fully reversible.
[The ideal body: media pedagogy].
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
Extended chiral algebras and the emergence of SU(2) quantum numbers in the Coulomb gas
NASA Astrophysics Data System (ADS)
Nichols, Alexander
2003-08-01
We study a set of chiral symmetries contained in degenerate operators beyond the `minimal' sector of the cp,q models. For the operators h(2j+2)q-1,1 = h1,(2j+2)p-1 at conformal weight [(j+1)p-1][(j+1)q-1], for every 2jinBbb N, we find 2j+1 chiral operators which have quantum numbers of a spin j representation of SU(2). We give a free-field construction of these operators which makes this structure explicit and allows their OPEs to be calculated directly without any use of screening charges. The first non-trivial chiral field in this series, at j = 1/2, is a fermionic or parafermionic doublet. The three chiral bosonic fields, at j = 1, generate a closed W-algebra and we calculate the vacuum character of these triplet models.
Quantum oscillations of the two-dimensional hole gas at atomically flat diamond surfaces
NASA Astrophysics Data System (ADS)
Takahide, Yamaguchi; Okazaki, Hiroyuki; Deguchi, Keita; Uji, Shinya; Takeya, Hiroyuki; Takano, Yoshihiko; Tsuboi, Hidetoshi; Kawarada, Hiroshi
2014-06-01
Shubnikov-de Haas oscillations are observed in atomically flat hydrogen-terminated diamond surfaces with high-density hole carriers introduced by the electric field effect using an ionic liquid. The Shubnikov-de Haas oscillations depend only on the magnetic field component perpendicular to the diamond surface, thus providing evidence of two-dimensional Fermi surfaces. The effective masses estimated from the temperature dependence of the oscillations are close to the cyclotron effective masses of the valence band maxima in diamond. The estimated quantum scattering time is one order of magnitude longer than the transport scattering time and indicates that the carrier mobility is locally as high as several thousand cm2/V s at low temperature.
Visualizing edge states with an atomic Bose gas in the quantum Hall regime.
Stuhl, B K; Lu, H-I; Aycock, L M; Genkina, D; Spielman, I B
2015-09-25
Bringing ultracold atomic gases into the quantum Hall regime is challenging. We engineered an effective magnetic field in a two-dimensional lattice with an elongated-strip geometry, consisting of the sites of an optical lattice in the long direction and of three internal atomic spin states in the short direction. We imaged the localized states of atomic Bose-Einstein condensates in this strip; via excitation dynamics, we further observed both the skipping orbits of excited atoms traveling down the system's edges, analogous to edge magnetoplasmons in two-dimensional electron systems, and a dynamical Hall effect for bulk excitations. Our technique involves minimal heating, which will be important for spectroscopic measurements of the Hofstadter butterfly and realizations of Laughlin's charge pump. PMID:26404830
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.
Computer Algebra for Computer Ideal-Variety Correspondence and Ideals in k[x
Kalla, Priyank
Computer Algebra for Computer Engineers Ideal-Variety Correspondence and Ideals in k[x] Priyank;Ideals Definition 1 A subset I R = k[x1, . . . , xn] is an ideal if: 0 I If f, g I, then f + g I If f . . . , fs = { s i=1 fihi : h1, . . . hs k[x1, . . . , xn]} (1) I = f1, f2 . . . , fs is an ideal generated
Hiromi Kaneko
2013-10-14
In our previous paper, we have investigated the thermodynamics of the quantum ultra-cold neutron gas trapped in the two-dimensional square-well potential on the Earth's gravitational field. We have pointed out that they have strong dependence on the shape of the trapping potential. In the present paper, we estimate the Fermi energy and the density distribution of the Fermi gas with two-dimensional harmonic oscillator potential, instead of the square-well potential. Then we discuss them in terms of the Fermi energy and the density distribution as compared with both of cases.
B. König; I. A. Merkulov; D. R. Yakovlev; W. Ossau; S. M. Ryabchenko; M. Kutrowski; T. Wojtowicz; G. Karczewski; J. Kossut
2000-01-01
An efficient energy-transfer channel from photocarriers to the Mn spin system via a two-dimensional electron gas (2DEG) in n-type modulation-doped Cd0.99Mn0.01Te\\/Cd0.76Mg0.24Te quantum wells has been found. The energy relaxation of photoexcited carriers is assumed to cause heating of the electron gas, which subsequently leads to an increase of the temperature of the Mn spin system. The mechanism of the energy
Thermal Casimir effect in ideal metal rectangular boxes
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
Quantum gases. Critical dynamics of spontaneous symmetry breaking in a homogeneous Bose gas.
Navon, Nir; Gaunt, Alexander L; Smith, Robert P; Hadzibabic, Zoran
2015-01-01
Kibble-Zurek theory models the dynamics of spontaneous symmetry breaking, which plays an important role in a wide variety of physical contexts, ranging from cosmology to superconductors. We explored these dynamics in a homogeneous system by thermally quenching an atomic gas with short-range interactions through the Bose-Einstein phase transition. Using homodyne matter-wave interferometry to measure first-order correlation functions, we verified the central quantitative prediction of the Kibble-Zurek theory, namely the homogeneous-system power-law scaling of the coherence length with the quench rate. Moreover, we directly confirmed its underlying hypothesis, the freezing of the correlation length near the transition. Our measurements agree with a beyond-mean-field theory and support the expectation that the dynamical critical exponent for this universality class is z = 3/2. PMID:25574021
Rare-gas precipitates in metals as quantum dots for polaritons
Goliney, I. Yu.; Sugakov, V. I.
2000-10-15
A study of the optical spectra of metals containing inclusions of rare-gas precipitates of spherical shape is presented. A unique feature of this system is that rare-gas atoms inside the precipitates form a crystal lattice even at temperatures much higher than room temperature. Energy spectra of the size quantization of excitons in Xe, Kr, Ar, and Ne precipitates in Al and their manifestation in reflection spectra are calculated, taking into account polariton effects (dipole-dipole exciton interactions), spatial dispersion, and mixing of the electronic excitations of the inclusion with collective excitations of the surrounding metal (plasmons). It was shown that (i) the proximity of energies of the exciton levels and the plasmons localized on the inclusion (surface plasmons) results in a gigantic shift (up to 1 eV) of the levels of coupled excitations, (ii) the transfer of the oscillator strength from the plasmon level to the exciton levels leads to the amplification of optical transitions in bubbles by several orders of magnitude. If the energy of the surface plasmon is smaller than the energy of the surface polariton (Ar, Ne), the latter is situated inside the discrete exciton spectrum and is coupled to the discrete exciton levels. In this case the surface polariton line in the reflection spectra is broadened by a set of dips representing quantized exciton levels. In the case of Xe and Kr in Al, the energy of the surface plasmon level is larger than the energy of the surface polariton. As a result, the surface polariton is pushed out of the exciton band and manifests itself in the reflection spectrum by a very narrow dip.
Rare-gas precipitates in metals as quantum dots for polaritons
NASA Astrophysics Data System (ADS)
Goliney, I. Yu.; Sugakov, V. I.
2000-10-01
A study of the optical spectra of metals containing inclusions of rare-gas precipitates of spherical shape is presented. A unique feature of this system is that rare-gas atoms inside the precipitates form a crystal lattice even at temperatures much higher than room temperature. Energy spectra of the size quantization of excitons in Xe, Kr, Ar, and Ne precipitates in Al and their manifestation in reflection spectra are calculated, taking into account polariton effects (dipole-dipole exciton interactions), spatial dispersion, and mixing of the electronic excitations of the inclusion with collective excitations of the surrounding metal (plasmons). It was shown that (i) the proximity of energies of the exciton levels and the plasmons localized on the inclusion (surface plasmons) results in a gigantic shift (up to 1 eV) of the levels of coupled excitations, (ii) the transfer of the oscillator strength from the plasmon level to the exciton levels leads to the amplification of optical transitions in bubbles by several orders of magnitude. If the energy of the surface plasmon is smaller than the energy of the surface polariton (Ar, Ne), the latter is situated inside the discrete exciton spectrum and is coupled to the discrete exciton levels. In this case the surface polariton line in the reflection spectra is broadened by a set of dips representing quantized exciton levels. In the case of Xe and Kr in Al, the energy of the surface plasmon level is larger than the energy of the surface polariton. As a result, the surface polariton is pushed out of the exciton band and manifests itself in the reflection spectrum by a very narrow dip.
Gas-Phase Spectroscopy of Biomolecular Building Blocks
NASA Astrophysics Data System (ADS)
de Vries, Mattanjah S.; Hobza, Pavel
2007-05-01
Gas-phase spectroscopy lends itself ideally to the study of isolated molecules and provides important data for comparison with theory. In recent years, we have seen enormous progress in the study of biomolecular building blocks in the gas phase. The motivation for such work is threefold: (a) It is important to distinguish between intrinsic molecular properties and properties that result from the biological environment. (b) Gas-phase spectroscopy of clusters provides insights into fundamental interactions and into microsolvation. (c) Gas-phase data support quantum-chemical calculations. This review focuses on the current status of (poly)amino acids and DNA bases. Recent results help elucidate structure and hydrogen-bonded interactions, as well as showcase a successful interplay between theory and experiment.
Ideal perturbed equilibria in tokamaks
NASA Astrophysics Data System (ADS)
Park, Jong-Kyu
Tokamaks are almost axisymmetric, but highly sensitive to a small non-axisymmetric magnetic field in the level of 10-4 compared to the axisymmetric magnetic field. The small non-axisymmetries can significantly degrade or improve the tokamak plasma performance. Only recently has the importance of understanding the plasma response to the small non-axisymmetries been appreciated. Since the non-axisymmetric field is almost static on the time scales of the equilibrium relaxation, the basic and fundamental understanding can be achieved by studying perturbed equilibria. The previous approach for these perturbed plasma states was to superpose the external vacuum field onto the axisymmetric equilibrium field. This is not self-consistent since it ignores the perturbed plasma currents arising as the plasma response. Ideal Perturbed Equilibrium Code (IPEC), which has been developed to include the plasma response effects, is based on the DCON and the VACUUM stability codes. IPEC solves free-boundary ideal equilibria when axisymmetric equilibria are perturbed by small non-axisymmetric perturbations. The complications related to the external boundary conditions are efficiently handled using equivalent surface currents on a control surface instead of directly using the current sources in the external coils. As the internal boundary conditions, the ideal constraints are used at the resonant surfaces, which prevent the destruction of flux surfaces by magnetic islands. IPEC solutions include the perturbed field and the displacement throughout the entire region, but in particular, there are the two important pieces of information: (1) the singular currents that shield out the resonant field driving the islands, and (2) the variation in the field strength on the deformed magnetic surfaces, or equivalently along the perturbed magnetic field lines. IPEC can determine both the strength of the resonant field that is trying to open magnetic islands and the variation in the field strength, which is essential for the evaluation of non-ambipolar transport. These IPEC solutions have been tested in cylindrical force-free limit, and also benchmarked against a perturbed equilibrium code for stellarators and a non-linear MHD code. Applications of IPEC are: (1) The opening of a magnetic island can stop the plasma rotation in a tokamak. This is called locking, which must be avoided for successful tokamak operations. The resonant field that tends to drive islands, when calculated by IPEC, gave a successful explanation for recent NSTX and DIII-D tokamak locking experiments, which were inconsistent when the plasma response was ignored. (2) IPEC results were also applied to study the parametric dependency of locking, based on data of three US major tokamaks, NSTX, DIII-D and C-MOD. This yielded different expectations and extrapolations to ITER, which will test the first burning plasma in a worldwide collaboration. (3) A non-axisymmetric variation in the field strength can strongly enhance rotational damping through non-ambipolar transport, or equivalently the Neoclassical Toroidal Viscosity (NTV). However, the previous approach using only the external field coupled with an asymptotic NTV calculations showed inconsistency between theory and experiment. In order to resolve the inconsistency, a new analytic treatment of NTV was developed to include important physics effects such as the particle precession and bounce-harmonic resonances. When the generalized NTV theory is coupled with the variation in the field strength calculated by IPEC, far better consistency is found between theory and experiment. Non-axisymmetric magnetic perturbations can be used for plasma control. To do the control, both the resonant field and the NTV must be determined to avoid degrading the plasma performance. A new control scheme is presented based on the coupling between the resonant field driving islands and the external field. The proposed scheme can determine dominant external field to which various locations in the plasma are most sensitive. The similarity of the dominant external
NASA Astrophysics Data System (ADS)
Carelli, Fabio; Gianturco, Francesco Antonio; Franz, Jan; Satta, Mauro
2015-06-01
Electron and positron scattering processes in the gas-phase are analysed for uracil and pyrimidine molecules using a multichannel quantum approach at energies close to threshold. The special effects on the scattering dynamics induced by the large dipole moments in both molecules on the spatial features of the continuum leptonic wavefunctions are here linked to the possible bound states of the Rydberg-like molecular anions or `positroned' molecules which could be reached via further couplings with molecular internal degrees of freedom.
Masahito Ikenaga; Koichi Nakamura; Akitomo Tachibana; Koh Matsumoto
2002-01-01
We have discussed the gas-phase parasitic reactions in MR3\\/H2\\/NH3 (M=Al, Ga, In; R=CH3, C2H5) systems following the elimination of methane or ethane in terms of the regional density functional theory by carrying out ab initio quantum chemical calculations. It is clearly shown that Al source gases enhance reactivity for both of R=CH3 and C2H5. Furthermore, the difference in reactivity between
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.
Wojcik, Michael D.; Phillips, Mark C.; Cannon, Bret D.; Taubman, Matthew S.
2006-10-01
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 ?m 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) and delivered a modest 5.3 mW at the tuning fork. This spectrometer was calibrated using the infrared absorber Freon-134a by performing a simultaneous absorption measurement using a 35 cm absorption cell. The NEAS of this instrument was determined to be 2 x 10{sup -8} W cm-1 Hz{sup -1/2}. A corresponding theoretical analysis of the instrument sensitivity is presented and is capable of quantitatively reproducing the experimental NEAS, indicating that the fundamental sensitivity of this technique is limited by the noise floor of the tuning fork itself.
Phillips, Kathy L; Sandler, Stanley I; Chiu, Pei C
2011-01-30
Nitroaromatic compounds (NACs) are widespread environmental contaminants, and the one-electron reduction potential (E?oH) is an important parameter used in modeling their environmental fate. We have identified a method that is both accurate and efficient to predict E?oH values for NACs, using gas-phase quantum mechanics (QM) calculations combined with empirical correlations. First, the adiabatic electron affinity (EA) at 0 K is calculated using the B98/MG3S method, and the predictions are scaled by a factor of 0.802 to account for systematic errors in the density functional calculations. Second, the E?oH values are predicted from a linear correlation between E?oH and EA. Using this method, E?oH values were predicted with a mean absolute deviation from measured values of 0.021 V for the 14 NACs used to obtain the correlation and 0.029 V for six additional NACs. This represents a substantial improvement in accuracy over predictions by other QM methods, which are affected by large errors in solvation or aqueous-phase calculations for some compounds. PMID:20662081
NASA Astrophysics Data System (ADS)
Li, Xin; Koloren?, Jind?ich; Mitas, Lubos
2011-08-01
We calculate the ground-state properties of an unpolarized two-component Fermi gas with the aid of the diffusion quantum Monte Carlo (DMC) methods. Using an extrapolation to the zero effective range of the attractive two-particle interaction, we find E/Efree in the unitary limit to be 0.212(2), 0.407(2), 0.409(3), and 0.398(3) for 4, 14, 38, and 66 atoms, respectively. Our calculations indicate that the dependence of the total energy on the effective range of the interaction Reff is sizable and the extrapolation to Reff=0 is therefore important for reaching the true unitary limit. To test the quality of nodal surfaces and to estimate the impact of the fixed-node approximation, we perform released-node DMC calculations for 4 and 14 atoms. Analysis of the released-node and the fixed-node results suggests that the main sources of the fixed-node errors are long-range correlations, which are difficult to sample in the released-node approaches due to the fast growth of the bosonic noise. Besides energies, we evaluate the two-body density matrix and the condensate fraction. We find that the condensate fraction for the 66-atom system converges to 0.56(1) after the extrapolation to the zero interaction range.
NASA Astrophysics Data System (ADS)
Baren, Randall E.; Parrish, Milton E.; Shafer, Kenneth H.; Harward, Charles N.; Shi, Quan; Nelson, David D.; McManus, J. Barry; Zahniser, Mark S.
2004-12-01
A compact, fast response, infrared spectrometer using four pulsed quantum cascade (QC) lasers has been applied to the analysis of gases in mainstream (MS) and sidestream (SS) cigarette smoke. QC lasers have many advantages over the traditional lead-salt tunable diode lasers, including near room temperature operation with thermoelectric cooling and single mode operation with improved long-term stability. The new instrument uses two 36 m, 0.3 l multiple pass absorption gas cells to obtain a time response of 0.1 s for the MS smoke system and 0.4 s for the SS smoke system. The concentrations of ammonia, ethylene, nitric oxide, and carbon dioxide for three different reference cigarettes were measured simultaneously in MS and SS smoke. A data rate of 20 Hz provides sufficient resolution to determine the concentration profiles during each 2 s puff in the MS smoke. Concentration profiles before, during and after the puffs also have been observed for these smoke constituents in SS smoke. Also, simultaneous measurements of CO 2 from a non-dispersive infrared (NDIR) analyzer are obtained for both MS and SS smoke. In addition, during this work, nitrous oxide was detected in both the MS and SS smoke for all reference cigarettes studied.
Patimisco, Pietro; Borri, Simone; Sampaolo, Angelo; Beere, Harvey E; Ritchie, David A; Vitiello, Miriam S; Scamarcio, Gaetano; Spagnolo, Vincenzo
2014-05-01
An innovative quartz enhanced photoacoustic (QEPAS) gas sensing system operating in the THz spectral range and employing a custom quartz tuning fork (QTF) is described. The QTF dimensions are 3.3 cm × 0.4 cm × 0.8 cm, with the two prongs spaced by ?800 ?m. To test our sensor we used a quantum cascade laser as the light source and selected a methanol rotational absorption line at 131.054 cm(-1) (?3.93 THz), with line-strength S = 4.28 × 10(-21) cm mol(-1). The sensor was operated at 10 Torr pressure on the first flexion QTF resonance frequency of 4245 Hz. The corresponding Q-factor was 74?760. Stepwise concentration measurements were performed to verify the linearity of the QEPAS signal as a function of the methanol concentration. The achieved sensitivity of the system is 7 parts per million in 4 seconds, corresponding to a QEPAS normalized noise-equivalent absorption of 2 × 10(-10) W cm(-1) Hz(-1/2), comparable with the best result of mid-IR QEPAS systems. PMID:24167816
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
Baren, Randall E; Parrish, Milton E; Shafer, Kenneth H; Harward, Charles N; Shi, Quan; Nelson, David D; McManus, J Barry; Zahniser, Mark S
2004-12-01
A compact, fast response, infrared spectrometer using four pulsed quantum cascade (QC) lasers has been applied to the analysis of gases in mainstream (MS) and sidestream (SS) cigarette smoke. QC lasers have many advantages over the traditional lead-salt tunable diode lasers, including near room temperature operation with thermoelectric cooling and single mode operation with improved long-term stability. The new instrument uses two 36 m, 0.3 l multiple pass absorption gas cells to obtain a time response of 0.1s for the MS smoke system and 0.4s for the SS smoke system. The concentrations of ammonia, ethylene, nitric oxide, and carbon dioxide for three different reference cigarettes were measured simultaneously in MS and SS smoke. A data rate of 20Hz provides sufficient resolution to determine the concentration profiles during each 2s puff in the MS smoke. Concentration profiles before, during and after the puffs also have been observed for these smoke constituents in SS smoke. Also, simultaneous measurements of CO(2) from a non-dispersive infrared (NDIR) analyzer are obtained for both MS and SS smoke. In addition, during this work, nitrous oxide was detected in both the MS and SS smoke for all reference cigarettes studied. PMID:15561630
Improved Classification of Mammograms Following Idealized Training
Hornsby, Adam N.; Love, Bradley C.
2014-01-01
People often make decisions by stochastically retrieving a small set of relevant memories. This limited retrieval implies that human performance can be improved by training on idealized category distributions (Giguère & Love, 2013). Here, we evaluate whether the benefits of idealized training extend to categorization of real-world stimuli, namely classifying mammograms as normal or tumorous. Participants in the idealized condition were trained exclusively on items that, according to a norming study, were relatively unambiguous. Participants in the actual condition were trained on a representative range of items. Despite being exclusively trained on easy items, idealized-condition participants were more accurate than those in the actual condition when tested on a range of item types. However, idealized participants experienced difficulties when test items were very dissimilar from training cases. The benefits of idealization, attributable to reducing noise arising from cognitive limitations in memory retrieval, suggest ways to improve real-world decision making. PMID:24955325
Huseyin Cakalli; Bipan Hazarika
2012-03-09
An ideal $I$ is a family of subsets of positive integers $\\textbf{N}$ which is closed under taking finite unions and subsets of its elements. A sequence $(x_n)$ of real numbers is said to be $I$-convergent to a real number $L$, if for each \\;$ \\varepsilon> 0$ the set $\\{n:|x_{n}-L|\\geq \\varepsilon\\}$ belongs to $I$. We introduce $I$-ward compactness of a subset of $\\textbf{R}$, the set of real numbers, and $I$-ward continuity of a real function in the senses that a subset $E$ of $\\textbf{R}$ is $I$-ward compact if any sequence $(x_{n})$ of points in $E$ has an $I$-quasi-Cauchy subsequence, and a real function is $I$-ward continuous if it preserves $I$-quasi-Cauchy sequences where a sequence $(x_{n})$ is called to be $I$-quasi-Cauchy when $(\\Delta x_{n})$ is $I$-convergent to 0. We obtain results related to $I$-ward continuity, $I$-ward compactness, ward continuity, ward compactness, ordinary compactness, ordinary continuity, $\\delta$-ward continuity, and slowly oscillating continuity.
NASA Astrophysics Data System (ADS)
Sharpe, G. J.; Luheshi, M. Y.; Braithwaite, M.; Falle, S. A. E. G.
2009-12-01
Highly non-ideal explosives, such as commercial ammonium nitrate based explosives used in mining and blasting, have critical charge diameters of several centimetres and relatively low detonation speeds. Shock polar match analyses between these explosives and confining inert materials give two main types of interactions. For the first type (denoted here by case I), the detonation drives an oblique shock into the confiner. For the second type (case II), a wave propagates in the confiner ahead of the detonation wave in the explosive. In case I, numerical simulations show that for a given explosive model there is a unique relationship (valid for all charge diameters and confinements) between the velocity of detonation (VoD) and the curvature of the detonation shock at the charge axis. This relationship is shown to be well predicted by a quasi-one-dimensional analysis. A simple detonation shock dynamics method which uses this relationship predicts the VoD provided the explosive is sufficiently confined (usually the case in mining), but is inaccurate in the limit of an unconfined charge. For commercial explosives confined by rocks, a significant proportion of problems are case II. Numerical simulations are performed to investigate the coupling mechanisms in these situations. It is found that, in agreement with an approximate theory, the detonation is driven up to VoDs near the confiner's sound speed, and the wave in the confiner weakly pre-compresses the explosive ahead of the detonation front.
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.
Unpolarized Fermi gas in squeezed anisotropic harmonic trap by Quantum Monte Carlo methods
NASA Astrophysics Data System (ADS)
Li, Xin; Mitas, Lubos
2012-02-01
Using diffusion Monte Carlo (DMC) method, we calculate the ground state properties of unpolarized Fermi gas at unitarity regime in both isotropic and anisotropic harmonic potentials. We study the effects of anisotropy by increasing the frequency in z direction ?z of the harmonic potential while keeping the frequency in x and y direction unchanged. The true unitarity regime is obtained by extrapolating the interaction range to zero and the calculations are done using the fixed-node diffusion Monte Carlo method. The trial function is of the BCS form with the pairing function expanded in appropriate linear combinations of the anisotropic oscillator eigenstates. We evaluate the binding energies for varying particle numbers and we estimate its behavior in the limit of large number of atoms. We estimate dependence of projected density profile and momentum distribution on the X-Y plane with respect to ?z. Our results can be readily used as a benchmark for the cold atom experiment with similar experimental set-up. Supported by ARO and NSF.
Gas-phase formation of the prebiotic molecule formamide: insights from new quantum computations
NASA Astrophysics Data System (ADS)
Barone, V.; Latouche, C.; Skouteris, D.; Vazart, F.; Balucani, N.; Ceccarelli, C.; Lefloch, B.
2015-10-01
New insights into the formation of interstellar formamide, a species of great relevance in prebiotic chemistry, are provided by electronic structure and kinetic calculations for the reaction NH2 + H2CO ? NH2CHO + H. Contrarily to what previously suggested, this reaction is essentially barrierless and can, therefore, occur under the low temperature conditions of intestellar objects thus providing a facile formation route of formamide. The rate coefficient parameters for the reaction channel leading to NH2CHO + H have been calculated to be A = 2.6 × 10-12 cm3 s-1, ? = -2.1 and ? = 26.9 K in the range of temperatures 10-300 K. Including these new kinetic data in a refined astrochemical model, we show that the proposed mechanism can well reproduce the abundances of formamide observed in two very different interstellar objects: the cold envelope of the Sun-like protostar IRAS16293-2422 and the molecular shock L1157-B2. Therefore, the major conclusion of this Letter is that there is no need to invoke grain-surface chemistry to explain the presence of formamide provided that its precursors, NH2 and H2CO, are available in the gas phase.
Ideal Free Distribution (IFD) Pattern: Consumers across Resource Patches
Caraco, Thomas
Ideal Free Distribution (IFD) Pattern: Consumers across Resource Patches Ideal: Information at IFD Suppose Consumers Not Ideal Perceptual Constraint: Consumers Limited in Ability to Distinguish Intake & Avoiding Predation Risk-sensitivity: "Overmatching" #12;Interference Model Consumers Ideal
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.
Girardeau, M. D.
2009-06-19
A model of two 1D ideal Bose gases A and B with strong odd-wave AB attractions induced by a p-wave AB Feshbach resonance is studied. The model is solved exactly by a Bose-Bose duality mapping, and it is shown that there is no A-component or B-component Bose-Einstein condensation and no AB-pair off-diagonal long-range order (ODLRO), but both AA-pair and BB-pair ODLRO. After generalization by adding even-wave AA and BB repulsions and reducing the strength of the odd-wave AB attraction by Feshbach resonance detuning, a quantum phase transition occurs between a phase with AB contact nodes and one with no such nodes.
Demagnetization Dynamics of a Unitary Fermi Gas
NASA Astrophysics Data System (ADS)
Thywissen, J. H.
2015-05-01
We observe the spin dynamics of a quantum degenerate Fermi gas of 40K near an s-wave interaction resonance. The starting point of our measurements is a transversely spin-polarized gas, where each atom is in a superposition of the lowest two Zeeman eigenstates. In the presence of an external gradient, a spin texture develops across the cloud, which drives diffusive spin currents. Spin transport is described with two coefficients: D0⊥, the transverse spin diffusivity, and ?, the Leggett-Rice parameter. Diffusion is a dissipative effect that increases the entropy of the gas, eventually creating a mixture of spin states. ? parameterizes the rate at which spin current precesses around the local magnetization. Using a spin-echo sequence, we measure the transport parameters for a range of interaction strengths and temperatures. At unitarity, we find D0⊥ = 2 . 3(4) ? / m and ? = 1 . 08(9) , where m is the atomic mass. In the limit of zero temperature, ? and D0⊥ are scale-invariant universal transport parameters of the unitary Fermi gas. The value of D0⊥ reveals strong scattering in the unitary gas, and is near its proposed quantum limit, such that the inferred value of the transport lifetime ?? is comparable to ? /?F . This raises the possibility that incoherent transport may play a role. The nonzero value of ? tells us that spin waves in unitary Fermi gas are dispersive, or in other words, that the gas has a spin stiffness in the long-wavelength limit. Time permitting, we will also discuss a time-resolved measurement of the contact, through which we observe the microscopic transformation of the gas from ideal to strongly correlated.
Fateev, Evgeny G
2013-01-01
The principles of quantum motors based on Casimir platforms (thin-film nanostructures are at issue) are discussed in plain language. The generation of quantum propulsion is caused by the noncompensated integral action of virtual photon momenta upon a configuration unit cell in the platform. The cells in a Casimir platform should be situated in a certain order with optimal geometric parameters. The evaluation of the quantum propulsion shows that, for example, ten square meters of ideal Casimir platforms (it is a complex single-layer structure) could make Cheops pyramid move!
Evgeny G. Fateev
2013-09-12
The principles of quantum motors based on Casimir platforms (thin-film nanostructures are at issue) are discussed in plain language. The generation of quantum propulsion is caused by the noncompensated integral action of virtual photon momenta upon a configuration unit cell in the platform. The cells in a Casimir platform should be situated in a certain order with optimal geometric parameters. The evaluation of the quantum propulsion shows that, for example, ten square meters of ideal Casimir platforms (it is a complex single-layer structure) could make Cheops pyramid move!
The mass and energy of a vapor bubble in a turbulent ideal fluid
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.
Initialization and readout of spin chains for quantum information transport
Kaur, Gurneet
Linear chains of spins acting as quantum wires are a promising approach for achieving scalable quantum information processors. Nuclear spins in apatite crystals provide an ideal test bed for the experimental study of quantum ...
Maintaining ideal body weight counseling sessions
Brammer, S.H.
1980-10-09
The purpose of this program is to provide employees with the motivation, knowledge and skills necessary to maintain ideal body weight throughout life. The target audience for this program, which is conducted in an industrial setting, is the employee 40 years of age or younger who is at or near his/her ideal body weight.
HOCHSCHILD COHOMOLOGY OF ALGEBRAS WITH HOMOLOGICAL IDEALS
Xi, Changchang
heredity ideal, then the long exact sequence provides information on H i (A), H i (B) and the extension, the quotient A # B := A/J is a homological epimorphism. Furthermore, if J is a heredity ideal of A, that is, J
Ideal and Nonideal Reasoning in Educational Theory
ERIC Educational Resources Information Center
Jaggar, Alison M.
2015-01-01
The terms "ideal theory" and "nonideal theory" are used in contemporary Anglophone political philosophy to identify alternative methodological approaches for justifying normative claims. Each term is used in multiple ways. In this article Alison M. Jaggar disentangles several versions of ideal and nonideal theory with a view to…
Evaluating human enhancements: the importance of ideals.
Roduit, Johann A R; Baumann, Holger; Heilinger, Jan-Christoph
2014-01-01
Is it necessary to have an ideal of perfection in mind to identify and evaluate true biotechnological human "enhancements", or can one do without? To answer this question we suggest employing the distinction between ideal and non-ideal theory, found in the debate in political philosophy about theories of justice: the distinctive views about whether one needs an idea of a perfectly just society or not when it comes to assessing the current situation and recommending steps to increase justice. In this paper we argue that evaluating human enhancements from a non-ideal perspective has some serious shortcomings, which can be avoided when endorsing an ideal approach. Our argument starts from a definition of human enhancement as improvement, which can be understood in two ways. The first approach is backward-looking and assesses improvements with regard to a status quo ante. The second, a forward-looking approach, evaluates improvements with regard to their proximity to a goal or according to an ideal. After outlining the limitations of an exclusively backward-looking view (non-ideal theory), we answer possible objections against a forward-looking view (ideal theory). Ultimately, we argue that the human enhancement debate would lack some important moral insights if a forward-looking view of improvement is not taken into consideration. PMID:25743059
NASA Astrophysics Data System (ADS)
Ksenafontov, Denis N.; Moiseeva, Natalia F.; Khristenko, Lyudmila V.; Karasev, Nikolai M.; Shishkov, Igor F.; Vilkov, Lev V.
2010-12-01
The geometric structure of piracetam was studied by quantum chemical calculations (DFT and ab initio), gas electron diffraction (GED), and FTIR spectroscopy. Two stable mirror symmetric isomers of piracetam were found. The conformation of pyrrolidine ring is an envelope in which the C4 atom deviates from the ring plane, the angle between the planes (C3 sbnd C4 sbnd C5) and (C2 sbnd C3 sbnd C5) is 154.1°. The direction of the deviation is the same as that of the side acetamide group. The piracetam molecule is stabilized in the gas phase by an intramolecular hydrogen bond between the N9H 2 group and the oxygen O6, bonded to C2. The principal structural parameters ( re, Å and ?e, degrees; uncertainties are 3 ?LS values) were found to be: r(?3 sbnd ?4) = 1.533(1), r(C4 sbnd C5) = 1.540(1), r(N1 sbnd C5) = 1.456(1), r(C2 sbnd C3) = 1.520(1), r(N1 sbnd C7) = 1.452(1), r(C7 sbnd C8) = 1.537(1), r(N1 sbnd C2) = 1.365(2), r(C8 sbnd N9) = 1.360(2), r(C2 dbnd O6) = 1.229(1), r(C8 dbnd O10) = 1.221(1), ?C2 sbnd N1 sbnd C5 = 113.4(6), ?N1 sbnd C2 sbnd C3 = 106.9(6), ?N1 sbnd C7 sbnd C8 = 111.9(6), ?C7 sbnd C8 sbnd N9 = 112.5(6), ?N1 sbnd C2 sbnd O6 = 123.0(4), ?C3 sbnd N1 sbnd C7 = 120.4(4), ?C7 sbnd C8 sbnd O10 = 120.2(4), ?C5 sbnd N1 sbnd C2 sbnd O6 = 170(6), ?C3 sbnd C2 sbnd N1 sbnd C7 = 178(6), ?C2 sbnd N1 sbnd C7 sbnd C8 = 84.2, ?N1 sbnd C7 sbnd C8 sbnd O10 = 111.9.
Gravity, Cartan geometry, and idealized waywisers
H. F. Westman; T. G. Zlosnik
2015-02-16
The primary aim of this paper is to provide a simple and concrete interpretation of Cartan geometry in terms of the mathematics of idealized waywisers. Waywisers, also called hodometers, are instruments traditionally used to measure distances. The mathematical representation of an idealized waywiser consists of a choice of symmetric space called a {\\em model space} and represents the `wheel' of the idealized waywiser. The geometry of a manifold is then completely characterized by a pair of variables $\\{V^A(x),A^{AB}(x)\\}$, each of which admit simple interpretations: $V^A$ is the point of contact between the waywiser's idealized wheel and the manifold whose geometry one wishes to characterize, and $A^{AB}=A_\\mu^{\\phantom{\\mu} AB}dx^\\mu$ is a connection one-form dictating how much the idealized wheel of the waywiser has rotated when rolled along the manifold. The familiar objects from differential geometry (e.g. metric $g_{\\mu\
Statistical problem of ideal gas in general 2-dimensional regions
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.
Mitosis, diffusible crosslinkers, and the ideal gas law.
Odde, David J
2015-03-12
During mitosis, molecular motors hydrolyze ATP to generate sliding forces between adjacent microtubules and form the bipolar mitotic spindle. Lansky et al. now show that the diffusible microtubule crosslinker Ase1p can generate sliding forces between adjacent microtubules, and it does so without ATP hydrolysis. PMID:25768899
NASA Astrophysics Data System (ADS)
Dakkouri, M.; Novikov, V. P.; Vilkov, L. V.
2010-08-01
The gas-phase electron diffraction experiment has shown that 1-monobromosilacyclobutane (MBSCB) exists in two conformational forms, the axial and equatorial with a significantly higher prevalence of the latter form (73(6)%). Various quantum mechanical procedures have been applied to investigate the thermodynamic equilibrium of the two conformers as well as the geometrical parameters of MBSCB. Among these methods was MP2/6-311++G(2df,2pd). This level of theory provided an axial to equatorial ratio of 29:71% and values for the geometrical parameters that are in good agreement with the experimental values except for the C-C bond length, which is by 0.02 Å shorter than in the experiment. The main geometrical parameters obtained from the experiment are: ( ra Å, ?a°): Si-C 1.872(3); C-C 1.583(6); Si-Br 2.225(3); ?CSiC 79.3; dihedral angle ? 28.8(52) ( axial) and 39.9(2) ( equatorial). Natural bond orbital (NBO) and atoms in molecule (AIM) analyses have been performed. Both, the donor-acceptor (Lewis and non-Lewis) orbital interactions and the topological properties of the charge density at the critical points ?( r) have consistently confirmed the experimental results and facilitated their interpretation. For the purpose of comparison and systematic investigation, we optimized the geometries and analyzed the NBOs and the topological properties of silacyclobutane, 1-monofluorosilacyclobutane (MFSCB), and 1-monochlorosilacyclobutane (MCSCB). Simple relationship has been found between the puckering angle ? and the puckering amplitude q, which allows for the prediction of either ? or q for mono- and dihaloginated silacyclobutanes. Additionally, NBO deletion analysis comprising NOSTAR, NOVIC, and NOGEM deletion algorithms have been conducted. Interesting conclusions regarding structure and conformational stability of the studied monohalogenated silacyclobutanes could be drawn from this analysis.
Jie Ma; Andrew Cheesman; Michael N. R. Ashfold; Kenneth G. Hay; Stephen Wright; Nigel Langford; Geoffrey Duxbury; Yuri A. Mankelevich
2009-01-01
CH4 and C2H2 molecules (and their interconversion) in hydrocarbon\\/rare gas\\/H2 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-1 using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or
Converging cylindrical shocks in ideal magnetohydrodynamics
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.
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.
Ideal regularization for learning kernels from labels.
Pan, Binbin; Lai, Jianhuang; Shen, Lixin
2014-08-01
In this paper, we propose a new form of regularization that is able to utilize the label information of a data set for learning kernels. The proposed regularization, referred to as ideal regularization, is a linear function of the kernel matrix to be learned. The ideal regularization allows us to develop efficient algorithms to exploit labels. Three applications of the ideal regularization are considered. Firstly, we use the ideal regularization to incorporate the labels into a standard kernel, making the resulting kernel more appropriate for learning tasks. Next, we employ the ideal regularization to learn a data-dependent kernel matrix from an initial kernel matrix (which contains prior similarity information, geometric structures, and labels of the data). Finally, we incorporate the ideal regularization to some state-of-the-art kernel learning problems. With this regularization, these learning problems can be formulated as simpler ones which permit more efficient solvers. Empirical results show that the ideal regularization exploits the labels effectively and efficiently. PMID:24824969
Dimensional transitions in thermodynamic properties of ideal Maxwell–Boltzmann gases
NASA Astrophysics Data System (ADS)
Aydin, Alhun; Sisman, Altug
2015-04-01
An ideal Maxwell–Boltzmann gas confined in various rectangular nanodomains is considered under quantum size effects. Thermodynamic quantities are calculated from their relations with the partition function, which consists of triple infinite summations over momentum states in each direction. To obtain analytical expressions, summations are converted to integrals for macrosystems by a continuum approximation, which fails at the nanoscale. To avoid both the numerical calculation of summations and the failure of their integral approximations at the nanoscale, a method which gives an analytical expression for a single particle partition function (SPPF) is proposed. It is shown that a dimensional transition in momentum space occurs at a certain magnitude of confinement. Therefore, to represent the SPPF by lower-dimensional analytical expressions becomes possible, rather than numerical calculation of summations. Considering rectangular domains with different aspect ratios, a comparison of the results of derived expressions with those of summation forms of the SPPF is made. It is shown that analytical expressions for the SPPF give very precise results with maximum relative errors of around 1%, 2% and 3% at exactly the transition point for single, double and triple transitions, respectively. Based on dimensional transitions, expressions for free energy, entropy, internal energy, chemical potential, heat capacity and pressure are given analytically valid for any scale.
Predicting film genres with implicit ideals.
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
Homological Invariants of Monomial and Binomial Ideals
Kummini, Neelakandhan Manoj
2008-08-19
and square-free monomial ideals in k[V]. This correspondence has an equivalent description. Let ? be a simplicial complex on V and I its Stanley-Reisner ideal. Then I = intersectiontext F?? ( ?F)R where ( ?F)R denotes the prime ideal generated by ?F :=V...?W, then for all x?? \\W, ??|? is a cone with vertex x, which, being contractible, does not have any homology. Applying Hochster?s formula (Discussion 1.3.7) we see that ?l,?(R/J) = 0. Now let ? ?W and F ?V. Then F ??|? if and only if I ?( ?F)R and F ?? if and only...
Predicting Film Genres with Implicit Ideals
Olney, Andrew McGregor
2013-01-01
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
NASA Astrophysics Data System (ADS)
Tishchenko, V. N.; Grachev, G. N.; Pavlov, A. A.; Smirnov, A. L.; Pavlov, A. A.; Golubev, M. P.
2008-01-01
The effect of energy removal from the combustion zone of a motionless optical pulsating discharge in the horizontal direction along the axis of a repetitively pulsed laser beam producing the discharge is discovered. The directivity diagram of a hot gas flow is formed during the action of hundreds of pulses. The effect is observed for short pulse durations, when the discharge efficiently generates shock waves. For long pulse durations, the heated gas propagates upward, as in a thermal source.
Puzzarini, Cristina; Biczysko, Malgorzata; Barone, Vincenzo; Largo, Laura; Peña, Isabel; Cabezas, Carlos; Alonso, José Luis
2014-02-01
Accurate structures of aminoacids in the gas phase have been obtained by joint microwave and quantum-chemical investigations. However, the structure and conformational behavior of ?-aminoacids once incorporated into peptide chains are completely different and have not yet been characterized with the same accuracy. To fill this gap, we present here an accurate characterization of the simplest dipeptide analogue (N-acetyl-glycinamide) involving peptidic bonds. State-of-the-art quantum-chemical computations are complemented by a comprehensive study of the rotational spectrum using a combination of Fourier transform microwave spectroscopy with laser ablation. The coexistence of the C7 and C5 conformers has been proved and energetically as well as spectroscopically characterized. This joint theoretical-experimental investigation demonstrated the feasibility of obtaining accurate structures for flexible small biomolecules, thus paving the route to the elucidation of the inherent behavior of peptides. PMID:26276605
Nattino, Francesco; Ueta, Hirokazu; Chadwick, Helen; van Reijzen, Maarten E; Beck, Rainer D; Jackson, Bret; van Hemert, Marc C; Kroes, Geert-Jan
2014-04-17
The dissociative chemisorption of methane on metal surfaces is of fundamental and practical interest, being a rate-limiting step in the steam reforming process. The reaction is best modeled with quantum dynamics calculations, but these are currently not guaranteed to produce accurate results because they rely on potential energy surfaces based on untested density functionals and on untested dynamical approximations. To help overcome these limitations, here we present for the first time statistically accurate reaction probabilities obtained with ab initio molecular dynamics (AIMD) for a polyatomic gas-phase molecule reacting with a metal surface. Using a general purpose density functional, the AIMD reaction probabilities are in semiquantitative agreement with new quantum-state-resolved experiments on CHD3 + Pt(111). The comparison suggests the use of the sudden approximation for treating the rotations even though CHD3 has large rotational constants and yields an estimated reaction barrier of 0.9 eV for CH4 + Pt(111). PMID:26269970
NASA Astrophysics Data System (ADS)
Puzzarini, Cristina; Biczysko, Malgorzata; Barone, Vincenzo; Largo, Laura; Peña, Isabel; Cabezas, Carlos; Alonso, José L.
2014-06-01
Accurate structures of aminoacids in the gas phase have been obtained by joint microwave and quantum-chemical investigations. However, the structure and conformational behavior of ?-aminoacids once incorporated into peptide chains are completely different and have not yet been characterized with the same accuracy. To fill this gap, we present here an accurate characterization of the simplest dipeptide analogue (N-acetylglycinamide) involving peptidic bonds. State-of-the-art quantum-chemical computations are complemented by a comprehensive study of the rotational spectrum using a combination of Fourier transform microwave spectroscopy with laser ablation. The coexistence of the C_7 and C_5 conformers has been proved and energetically as well as spectroscopically characterized. This joint theoretical-experimental investigation demonstrated the feasibility of obtaining accurate structures for flexible small biomolecules, thus paving the route to the elucidation of the inherent behavior of peptides.
Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.
1997-11-01
The results of the study are aimed at improvement of group-contribution methodology for estimation of thermodynamic properties of organic substances. 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 the condensed phase, vapor-pressure measurements, and differential scanning calorimetric (DSC) heat-capacity measurements. Ideal-gas enthalpies of formation of hexachloroprop-1-ene, N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, dimethyl carbonate, di-n-octyl sulfide, dicyclohexyl sulfide, diethylenetriamine, tetrakis(dimethylamino)ethylene, piperazine, and 1,2,4-triazolo[1,5-a]pyrimidine are reported. Enthalpies of fusion were determined for N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, piperazine and 1,2,4-triazolo[1,5-a]pyrimidine. Two-phase (solid + vapor) or (liquid + vapor) heat capacities were determined from 300 K to the critical region or earlier decomposition temperature for each compound studied. Liquid-phase densities along the saturation line were measured for N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, dimethyl carbonate, and dicyclohexyl sulfide. For dimethyl carbonate and piperazine, critical temperatures and critical densities were determined from the DSC results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for hexachloroprop-1-ene, di-n-octyl sulfide, dicyclohexyl sulfide, and diethylenetriamine. Group-additivity parameters and 1,4-interaction terms useful in the application of group-contribution correlations were derived.
Experimental study of the thermodynamics of an interacting trapped Bose-Einstein condensed gas
Thywissen, Joseph
law, N0/N=1- T/Tc 0 3 , where Tc 0 is the ideal-gas condensation temperature in the thermodynamic energy, we measure unambiguous deviations from ideal-gas thermodynamics and obtain good agreement ideal gas behavior are small [4Â9]. Although sev- eral key thermodynamical properties, such as condensed
Ideal fluid and acceleration of the universe
O. Gorbunova
2006-08-07
The solution of the dark energy problem in models without scalars is presented. It is shown that a late-time accelerating cosmology may be generated by an ideal fluid with some implicit equation of state.
Medical learning curves and the Kantian ideal.
Le Morvan, P; Stock, B
2005-09-01
A hitherto unexamined problem for the "Kantian ideal" that one should always treat patients as ends in themselves, and never only as a means to other ends, is explored in this paper. The problem consists of a prima facie conflict between this Kantian ideal and the reality of medical practice. This conflict arises because, at least presently, medical practitioners can only acquire certain skills and abilities by practising on live, human patients, and given the inevitability and ubiquity of learning curves, this learning requires some patients to be treated only as a means to this end. A number of ways of attempting to establish the compatibility of the Kantian Ideal with the reality of medical practice are considered. Each attempt is found to be unsuccessful. Accordingly, until a way is found to reconcile them, we conclude that the Kantian ideal is inconsistent with the reality of medical practice. PMID:16131552
Ideals and flexibility in close relationships
Campbell, Lorne John
1998-01-01
Two studies examined the roles that ideal standards aphics. for a romantic partner, and the flexibility of these standards, play in relationships. In the first study, 239 men and women involved in dating relationships were asked to rate themselves...
Medical learning curves and the Kantian ideal
Le Morvan, P; Stock, B
2005-01-01
A hitherto unexamined problem for the "Kantian ideal" that one should always treat patients as ends in themselves, and never only as a means to other ends, is explored in this paper. The problem consists of a prima facie conflict between this Kantian ideal and the reality of medical practice. This conflict arises because, at least presently, medical practitioners can only acquire certain skills and abilities by practising on live, human patients, and given the inevitability and ubiquity of learning curves, this learning requires some patients to be treated only as a means to this end. A number of ways of attempting to establish the compatibility of the Kantian Ideal with the reality of medical practice are considered. Each attempt is found to be unsuccessful. Accordingly, until a way is found to reconcile them, we conclude that the Kantian ideal is inconsistent with the reality of medical practice. PMID:16131552
McCall, Benjamin J.
Cascade Lasers Prospectus for Preliminary Examination Department of Chemistry, School of Chemical Sciences University of Illinois Jacob T. Stewart 29 April 2011 B124 CLSL 11:00 AM #12;1 Introduction Quantum cascade spectrum by varying the underlying quantum well structure of the laser chip. The original lasers had
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.