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1

High resolution kinetic beam schemes in generalized coordinates for ideal quantum gas dynamics  

Microsoft Academic Search

A class of high resolution kinetic beam schemes in multiple space dimensions in general coordinates system for the ideal quantum gas is presented for the computation of quantum gas dynamical flows. The kinetic Boltzmann equation approach is adopted and the local equilibrium quantum statistics distribution is assumed. High-order accurate methods using essentially non-oscillatory interpolation concept are constructed. Computations of shock

Yu-Hsin Shi; J. C. Huang; J. Y.. Yang

2007-01-01

2

Relaxation dynamics of a quantum Brownian particle in an ideal gas  

E-print Network

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.

Bassano Vacchini; Klaus Hornberger

2007-06-29

3

Relaxation dynamics of a quantum Brownian particle in an ideal gas  

E-print Network

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.

Vacchini, Bassano

2007-01-01

4

Relaxation dynamics of a quantum Brownian particle in an ideal gas  

NASA Astrophysics Data System (ADS)

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 Schrödinger and the Heisenberg picture.

Vacchini, B.; Hornberger, K.

2007-12-01

5

Ideal Gas Laws  

NSDL National Science Digital Library

This lab manual contains descriptions of a series of laboratories covering the ideal gas laws and ideal gas processes. These experiments are designed for introductory high school and college introductory physics, chemistry, and engineering courses. Each experiment includes the intended audience, learning goals, and a short introduction to the physics. The experiments include Boyleâs Law, work done in an isothermal process, adiabatic processes, thermodynamic cycles, and the heat capacity of a gas. These labs are designed for an adiabatic gas law apparatus developed at Andrews University.

Kutzner, Mickey; Wong, Peter

2011-11-18

6

High Resolution Quantum Kinetic Beam Schemes and Its Applications to Ideal Quantum Gas Dynamical Flows  

Microsoft Academic Search

Extensive theoretical and computational methods have been developed to solve the Euler equations of classical gas dynamics.\\u000a Among the various methods such as the exact and approximate Riemann solvers [5, 12], most are constructed based on the hyperbolic\\u000a conservation laws of the Euler equations. Some kinetic methods have been devised in the past to solve the Euler equations\\u000a of classical

Y. H. Shi; J. Y. Yang

7

Ideal Gas Expansion  

NSDL National Science Digital Library

The EJS Ideal Gas Expansion model simulates a two-dimensional ideal gas in a square box. This simulation can be used as part of the activity described in "The Statistical Interpretation of Entropy: An Activity" by Todd Timberlake, to be published in The Physics Teacher. In the model, the particles are initially all on the left (red) side of the box with otherwise random positions and random velocities (distributed according to a Maxwell distribution). Separate windows show the motion of the gas particles, a plot of the number of particles on each side versus time, and a histogram of the number of occurrences of a given number of particles on the left. The user can modify this simulation if EJS is installed locally by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. EJS Ideal Gas Expansion model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_entropy_IdealGasExpansion.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional EJS models re available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Timberlake, Todd

2010-06-18

8

Non ideal gas behavior  

SciTech Connect

For a closed Thermodynamic System in equilibrium, the internal energy of the system (U) is a function of two variables. The equilibrium states of a closed system, for example, described by means of 3 thermodynamic coordinates P, V, and T are completely determined by only two, since the third is fixed by the equation of state. For this reason the internal energy (U) may be considered as a function of only two (any two) of the other thermodynamic coordinates. If we use the two variable chain rule with U = f(T,V), we get the following: dU = ({partial_derivative}U/{partial_derivative}T) {sub v} dT + ({partial_derivative}U/{partial_derivative}V){sub T} dV. The first partial derivative is the heat capacity at constant volume. The second partial derivative is zero for an ideal gas, since interactions between the gas molecules is neglected the internal energy does not change with a change in volume at constant T. The purpose of this paper is to evaluate this second partial derivative for several non ideal equations of state, using mathematics and a software package {open_quotes}Mathematica.{close_quotes} The results (graphics and tables) illustrate the conditions where forces of attraction become significant. Next we see where the forces of repulsion becomes important.

Wakefield, C.B.

1996-12-31

9

Ideal Gas Law and the Gas Constant  

NSDL National Science Digital Library

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.

Blauch, David N.

10

Chemical Potential for the Interacting Classical Gas and the Ideal Quantum Gas Obeying a Generalized Exclusion Principle  

ERIC Educational Resources Information Center

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…

Sevilla, F. J.; Olivares-Quiroz, L.

2012-01-01

11

Ideal Gas with Maxwell's Demon  

NSDL National Science Digital Library

The EJS Ideal Gas with Maxwell's Demon model simulates a two-dimensional ideal gas in a square box, monitored by Maxwell's Demon (which allows only faster than average particles to move from the right side to the left side, while allowing only slower than average particles to move the other way). This simulation can be used as part of the activity described in "The Statistical Interpretation of Entropy: An Activity" by Todd Timberlake, to be published in The Physics Teacher. In the model, the particles are initially spread throughout the box with random positions and random velocities (with a Maxwell distribution of speeds). One window shows an animation of the motion of the particles in the box, while another window plots the temperature of the gas on each side of the box as a function of time. The user can turn the Demon on/off, or reverse the velocities of all particles. You can modify this simulation if you have EJS installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. EJS Ideal Gas with Maxwell's Demon model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_entropy_IdealGasMaxwellsDemon.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional EJS models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Timberlake, Todd

2010-07-01

12

STP Temperature Measurement Ideal Gas Program  

NSDL National Science Digital Library

The STP DemonIdealGas program displays a histogram of the energy of a demon that exchanges energy with an ideal gas of particles. The purpose of this simulation is to understand why the demon acts as a perfect thermometer and why its mean energy is a measure of the temperature of the gas. The default system is a one-dimensional ideal gas of N=40 particles. Additional states and parameters can be specified using the Display|Switch GUI menu item. STP DemonIdealGas is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double-clicking the stp_DemonIdealGas.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2008-05-28

13

Box of Ideal Gas in Free Fall  

E-print Network

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.

Dawood Kothawala

2011-08-31

14

Ideal Gas Laws: Experiments for General Chemistry  

ERIC Educational Resources Information Center

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)

Deal, Walter J.

1975-01-01

15

STP Ideal Gas Number Of States Program  

NSDL National Science Digital Library

The STP IdealGasNumberOfStates program numerically evaluates the number of states of an ideal gas and demonstrates finite size effects by plotting the actual number of states and the asymptotic expression. The default is two-dimensional system (d=2). STP IdealGasNumberOfStates is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double clicking the stp_IdealGasNumberOfStates.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-02-17

16

Ideal shear strength of a quantum crystal.  

PubMed

Using path-integral Monte Carlo simulations, we compute the ideal shear strength (ISS) on the basal plane of hcp (4)He. The failure mode upon reaching the ISS limit is characterized by the homogeneous nucleation of a stacking fault and it is found to be anisotropic, consistent with Schmid's law of resolved shear stress. Comparing the ISS of hcp (4)He to a large set of classical crystals shows that it closely fits the approximately universal modified Frenkel model of ideal strength. In addition to giving quantitative stress levels for the homogeneous nucleation of extended defects in hcp (4)He, our findings lend support to assumptions in the literature that inherently classical models remain useful for the description of mechanical behavior in quantum crystals. PMID:24785047

Borda, Edgar Josué Landinez; Cai, Wei; de Koning, Maurice

2014-04-18

17

Quantum ideal hydrodynamics on the lattice  

E-print Network

After discussing the problem of defining the hydrodynamic limit from microscopic scales, we give an introduction to ideal hydrodynamics in the Lagrange picture, and show that it can be viewed as a field theory, which can be quantized using the usual Feynman sum-over-paths prescription. We then argue that this picture can be connected to the usually neglected thermal microscopic scale in the hydrodynamic expansion. After showing that this expansion is generally non-perturbative, we show how the lattice can be used to understand the impact quantum and thermal fluctuations can have on the fluid behavior.

Tommy Burch; Giorgio Torrieri

2013-11-13

18

Equation of State - Ideal Gas  

NSDL National Science Digital Library

Gases have various observable properties, such as pressure (p), temperature (T), mass (m), and volume (V). Careful scientific observation has determined that these variables are related to one another, and the values of these properties determine the state of the gas. Users can read an explanation of the three laws (Boyle's Law, Charles' Law, and Gay-Lussac's Law) that describe the properties of gases and observe how gases behave under changing conditions.

2001-06-01

19

Derivation of the Ideal Gas Law  

ERIC Educational Resources Information Center

Undergraduate and graduate physics and chemistry books usually state that combining the gas laws results in the ideal gas law. Leaving the derivation to the students implies that this should be a simple task, most likely a substitution. Boyle's law, Charles's law, and the Avogadro's principle are given under certain conditions; therefore, direct…

Laugier, Alexander; Garai, Jozsef

2007-01-01

20

Thermostatistics of the polymeric ideal gas  

NASA Astrophysics Data System (ADS)

In this paper, we formulate statistical mechanics of the polymerized systems in the semiclassical regime. On the corresponding polymeric symplectic manifold, we set up a noncanonical coordinate system in which all of the polymeric effects are summarized in the density of states. Since we show that the polymeric effects only change the number of microstates of a statistical system, working in this coordinate is quite reasonable from the statistical point of view. The results show that the number of microstates decreases due to existence of an upper bound for the momentum of the test particles in the polymer framework. We obtain a corresponding canonical partition function by means of the deformed density of states. By using the partition function, we study thermodynamics of the ideal gas in the polymer framework and show that our results are in good agreement with those that arise from the full quantum consideration at high temperature, and they coincide with their usual counterpart in the limit of low temperature.

Gorji, M. A.; Nozari, K.; Vakili, B.

2014-08-01

21

Thermodynamics of Ideal Gas in Cosmology  

E-print Network

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.

Ying-Qiu Gu

2007-08-22

22

Standard thermodynamic properties of nitrobenzene in the ideal gas state  

Microsoft Academic Search

The standard enthalpy of formation of gaseous nitrobenzene was calculated by the G3X nonempirical quantum-mechanical method.\\u000a The value obtained (56 kJ\\/mol) was noticeably lower than the experimental enthalpy, which casts doubt on the accuracy of measurements.\\u000a The thermodynamic functions (C°\\u000a p\\u000a , S°, ?[G° ? H°(0)]\\/T, H° ? H°(0), ?f\\u000a H°, and ?f\\u000a G°) of nitrobenzene in the ideal gas

O. V. Dorofeeva; N. F. Moiseeva

2008-01-01

23

How is the Ideal Gas Law Explanatory?  

NASA Astrophysics Data System (ADS)

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.

Woody, Andrea I.

2013-07-01

24

Information, Entropy, and the Classical Ideal Gas  

NASA Astrophysics Data System (ADS)

The physical basis of the canonical and grand canonical distributions is questioned. In particular, we question the usual methods by which these distributions are derived, namely that fluctuations in entropy around energy and particle number are assumed to occur when the entropy depends only on variables which cannot themselves fluctuate. We show, starting from the Maxwellian velocity distribution, that the probability that a classical ideal gas at a fixed temperature occupies a given energy state corresponds not to the canonical ensemble of classical statistical mechanics but to the Gamma distribution. Computer simulations of a hard-sphere fluid demonstrate the principles. The analysis is extended to open systems in which the number of particles fluctuates and we show that for a system connected to a particle reservoir the Poisson distribution governs the probability of finding a given number of particles. The resulting probability distributions are used to calculate the Shannon information entropy which is then compared with the thermodynamic entropy. We argue that information theoretic entropy and thermodynamic entropy, whilst related, are not necessarily identical and that the information entropy contains non-thermodynamic components.

Sands, David; Dunning-Davies, Jeremy

2013-09-01

25

Ideal Electron Gas & Absorption Lines 2 November 2011  

E-print Network

radius. Since the temperature gradient is negative, the region from which they escape is cooler. Near an absorption line. #12;ideal electron gas & absorption lines 4 3. Let's estimate the lowest temperature whereIdeal Electron Gas & Absorption Lines 2 November 2011 Goals · Review some different regimes

Militzer, Burkhard

26

S10-Ideal gas 1 Page 1 of 7 IDEAL AND NON-IDEAL GASES  

E-print Network

assumptions -- the gas molecules are very small (they have no volume) and the molecules are non- interacting molecules are far apart. The purpose of the experiment is to determine experimentally how the pressure P and represents the total volume per mole of gas that is inaccessible to other molecules because it is already

Glashausser, Charles

27

Gas lift systems make ideal offshore workers  

SciTech Connect

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.

NONE

1999-05-01

28

Lorentz covariant statistical mechanics and thermodynamics of the relativistic ideal gas and preferred frame  

E-print Network

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.

K. Kowalski; J. Rembielinski; K. A. Smolinski

2007-12-17

29

Lorentz covariant statistical mechanics and thermodynamics of the relativistic ideal gas and preferred frame  

SciTech Connect

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.

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

30

On Brownian motion in ideal gas and related principles  

E-print Network

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

Yuriy E. Kuzovlev

2008-06-25

31

Computer program for calculation of ideal gas thermodynamic data  

NASA Technical Reports Server (NTRS)

Computer program calculates ideal gas thermodynamic properties for any species for which molecular constant data is available. Partial functions and derivatives from formulas based on statistical mechanics are provided by the program which is written in FORTRAN 4 and MAP.

Gordon, S.; Mc Bride, B. J.

1968-01-01

32

Anomaly/Transport in an Ideal Weyl gas  

E-print Network

We study some of the transport processes which are specific to an ideal gas of relativistic Weyl fermions and relate the corresponding transport coefficients to various anomaly coefficients of the system. We propose that these transport processes can be thought of as arising from the continuous injection of chiral states and their subsequent adiabatic flow driven by vorticity. This in turn leads to an elegant expression relating the anomaly induced transport coefficients to the anomaly polynomial of the Ideal Weyl gas.

R. Loganayagam; Piotr Surówka

2012-01-13

33

Hierarchy of free heat convection models for an ideal gas  

Microsoft Academic Search

Derivations of different asymptotic models of the free heat convection of an ideal gas are presented. By comparing solutions to the convection problem for a closed rectangular region, obtained on the basis of the full system of Navier-Stokes equations for a compressible gas, with those based on the models proposed here, the applicability limits of the models are analyzed with

O. A. Nekhamkina; D. A. Nikulin; M. Kh. Strelets

1989-01-01

34

Implications of Minimal Length Scale on the Statistical Mechanics of Ideal Gas  

E-print Network

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.

Kourosh Nozari; S. H. Mehdipour

2006-01-15

35

Direct simulation methods for compressible inviscid ideal-gas flow  

Microsoft Academic Search

Two novel schemes are proposed for the calculation of compressible flow of an ideal fluid. One method is the equilibrium analog of the well-known discrete-particle direct simulation Monte Carlo method for the treatment of nonequilibrium ideal-gas flows. The second follows from an analytical treatment of the model inertial-transport mechanisms inherent in the first scheme. Accounts of the methods are presented

D. I. Pullin

1980-01-01

36

Effective Dynamics of a Tracer Particle Interacting with an Ideal Bose Gas  

NASA Astrophysics Data System (ADS)

We study a system consisting of a heavy quantum particle, called the tracer particle, coupled to an ideal gas of light Bose particles, the ratio of masses of the tracer particle and a gas particle being proportional to the gas density. All particles have non-relativistic kinematics. The tracer particle is driven by an external potential and couples to the gas particles through a pair potential. We compare the quantum dynamics of this system to an effective dynamics given by a Newtonian equation of motion for the tracer particle coupled to a classical wave equation for the Bose gas. We quantify the closeness of these two dynamics as the mean-field limit is approached (gas density ). Our estimates allow us to interchange the thermodynamic with the mean-field limit.

Deckert, Dirk-André; Fröhlich, Jürg; Pickl, Peter; Pizzo, Alessandro

2014-06-01

37

Experimental verification of Boyle's law and the ideal gas law  

NASA Astrophysics Data System (ADS)

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.

Trifonov Ivanov, Dragia

2007-03-01

38

Experimental Verification of Boyle's Law and the Ideal Gas Law  

ERIC Educational Resources Information Center

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…

Ivanov, Dragia Trifonov

2007-01-01

39

Experimental verification of Boyle's law and the ideal gas law  

Microsoft Academic Search

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.

Dragia Trifonov Ivanov

2007-01-01

40

David Maloney's Physics Examples: Thermo Example 3-Ideal Gas Behavior  

NSDL National Science Digital Library

This item is an annotated homework problem involving an ideal gas contained in a cylinder with a movable piston. The author provides explicit explanations of isothermal, adiabatic, isobaric, and isochoric processes to guide users in solving for a number of unknowns. This item is part of a larger collection of introductory physics homework examples.

Maloney, David

2008-10-03

41

Theory of vortical helical ideal gas flows in laval nozzles  

Microsoft Academic Search

An asymptotic solution is found for the direct problem of the motion of an arbitrarily vortical helical ideal gas flow in a nozzle. The solution is constructed in the form of double series in powers of parameters characterizing the curvature of the nozzle wall at the critical section and the intensity of stream vorticity. The solution obtained is compared with

Yu. A. Gostintsev; O. A. Uspenskii

1978-01-01

42

On the Stability of Vortices in an Ideal Gas  

Microsoft Academic Search

Two distinct mechanisms of three-dimensional instability in compressible planar vortices in an ideal gas are presented. Both mechanisms have been obtained with the geometrical optics (WKB) stability theory which consists in studying the evolution of short-wavelength disturbances localized along the trajectories of the vortex. The first one corresponds to parametric resonances arising when a vortex is periodically compressed; the resulting

Stephane Leblanc; Anne Le Duc; Lionel Le Penven

2000-01-01

43

A Demonstration of Ideal Gas Principles Using a Football.  

ERIC Educational Resources Information Center

Uses a true-to-life story of accusations made against a college football team to illustrate ideal gas laws. Students are asked to decide whether helium-filled footballs would increase punt distances and how to determine whether a football contained air or helium. (WRM)

Bare, William D.; Andrews, Lester

1999-01-01

44

Quantum-statistics-induced flow patterns in driven ideal Fermi gases  

NASA Astrophysics Data System (ADS)

While classical or quantum interacting liquids become turbulent under sufficiently strong driving, it is not obvious what flow pattern an ideal quantum gas develops under similar conditions. Unlike classical noninteracting particles which exhibit rather trivial flow, ideal fermions have to satisfy the exclusion principle, which acts as a form of collective repulsion. We thus study the flow of an ideal Fermi gas as it is driven out of a narrow orifice of width comparable to the Fermi wavelength, employing both a microcanonical approach to transport, and solving a Lindblad equation for Markovian driving leads. Both methods are in good agreement and predict an outflowing current density with a complex microscopic pattern of vorticity in the steady state. Applying a bias of the order of the chemical potential results in a short-range correlated antiferromagnetic vorticity pattern, corresponding to local moments of the order of a tenth of a magneton, e?/2m, if the fermions are charged. The latter may be detectable by magnetosensitive spectroscopy in strongly driven cold gases (atoms) or clean electronic nanostructures (electrons).

Beria, Marco; Iqbal, Yasir; Di Ventra, Massimiliano; Müller, Markus

2013-10-01

45

Effect of the Minimal Length on Bose-Einstein Condensation in the Relativistic Ideal Bose Gas  

E-print Network

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.

Zhang, Xiuming

2014-01-01

46

Effect of the Minimal Length on Bose-Einstein Condensation in the Relativistic Ideal Bose Gas  

E-print Network

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.

Xiuming Zhang; Chi Tian

2014-10-10

47

How many is different? Answer from ideal Bose gas  

NASA Astrophysics Data System (ADS)

How many H2O molecules are needed to form water? While the precise answer is not known, it is clear that the answer should be a finite number rather than infinity. We revisit with care the ideal Bose gas confined in a cubic box which is discussed in most statistical physics textbooks. We show that the isobar of the ideal gas zigzags on the temperature-volume plane featuring a boiling-like discrete phase transition, provided the number of particles is equal to or greater than a particular value: 7616. This demonstrates for the first time how a finite system can feature a mathematical singularity and realize the notion of 'Emergence', without resorting to the thermodynamic limit.

Park, Jeong-Hyuck

2014-03-01

48

Relativistic ideal Fermi gas at zero temperature and preferred frame  

SciTech Connect

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.

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

49

On the Stability of Vortices in an Ideal Gas  

Microsoft Academic Search

Two distinct mechanisms of three-dimensional instability in compressible planar vortices in an ideal gas are presented. Both\\u000a mechanisms have been obtained with the geometrical optics (WKB) stability theory which consists in studying the evolution\\u000a of short-wavelength disturbances localized along the trajectories of the vortex. The first one corresponds to parametric resonances\\u000a arising when a vortex is periodically compressed; the resulting

Stéphane Leblanc; Anne Duc; Lionel Penven

50

Quantum arrival and dwell times via idealized clocks  

SciTech Connect

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

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

2011-08-15

51

Correlation of the ideal gas properties of five aromatic hydrocarbons  

SciTech Connect

The ideal gas thermodynamic properties of isobaric heat capacity, entropy, and enthalpy have been correlated for benzene, toluene, o-xylene, m-xylene, and p-xylene by a uniform, semiempirical function of temperature. The correlation is based on literature values calculated from statistical mechanics for temperature up to 1,500K for benzene and up to 3,000K for the other molecules. The temperature function chosen is more accurate than that used for previous correlations, and can be used in a wider temperature range.

Laesecke, A. (National Inst. of Standards and Technology, Boulder, CO (United States))

1993-04-01

52

What Is Entropy? Advanced Undergraduate Performance Comparing Ideal Gas Processes  

NSDL National Science Digital Library

We report data on upper-level student understanding of entropy and the Second Law of Thermodynamics when comparing the isothermal and free expansions of an ideal gas. Data from pre- and post-instruction written questions are presented, and several noteworthy features of student performance are identified and discussed. These features include ways students think about these topics prior to instruction as well as specific difficulties and other interesting aspects of student thought that persist after instruction. Implications for future research are also addressed.

Bucy, Brandon; Thompson, John R.; Mountcastle, Donald B.

2009-07-13

53

Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas  

NASA Astrophysics Data System (ADS)

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

Sanner, Christian; Su, Edward J.; Keshet, Aviv; Gommers, Ralf; Shin, Yong-Il; Huang, Wujie; Ketterle, Wolfgang

2010-07-01

54

Isobaric expansion coefficient and isothermal compressibility for a finite-size ideal Fermi gas system  

NASA Astrophysics Data System (ADS)

Due to quantum size effects (QSEs), the isobaric thermal expansion coefficient and isothermal compressibility well defined for macroscopic systems are invalid for finite-size systems. The two parameters are redefined and calculated for a finite-size ideal Fermi gas confined in a rectangular container. It is found that the isobaric thermal expansion coefficient and isothermal compressibility are generally anisotropic, i.e., they are generally different in different directions. Moreover, it is found the thermal expansion coefficient may be negative in some directions under the condition that the pressures in all directions are kept constant.

Su, Guozhen; Chen, Liwei; Chen, Jincan

2014-06-01

55

Fluctuation theorem for the effusion of an ideal gas B. Cleuren* and C. Van den Broeck  

E-print Network

Fluctuation theorem for the effusion of an ideal gas B. Cleuren* and C. Van den Broeck Hasselt of the entropy production for the effusion of an ideal gas between two com- partments is calculated explicitly, 05.20. y I. INTRODUCTION Effusion is the motion of a gas through a small pore or opening. The linear

Kawai, Ryoichi

56

Ideal quantum glass transitions: Many-body localization without quenched disorder  

NASA Astrophysics Data System (ADS)

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.

Schiulaz, M.; Müller, M.

2014-08-01

57

High School Forum. The Solution: "Derivation of the Ideal Gas Law."  

ERIC Educational Resources Information Center

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)

Herron, J. Dudley, Ed.

1980-01-01

58

CHAPTER 5 -SYSTEMS UNDER PRESSURE 5.1 Ideal gas law  

E-print Network

CHAPTER 5 - SYSTEMS UNDER PRESSURE 5.1 Ideal gas law The quantitative study of gases goes back more than three centuries. In 1662, Robert Boyle showed that at a fixed temperature T, the product as it is heated. These two observations are combined into an expression known as the ideal gas law, which we

Boal, David

59

Fluctuation theorem for entropy production during effusion of a relativistic ideal gas B. Cleuren,1  

E-print Network

Fluctuation theorem for entropy production during effusion of a relativistic ideal gas B. Cleuren,1 production for the effusion of a relativistic ideal gas is calculated explicitly. This result of the fundamental laws of nature: time revers- ibility and time translational invariance. The effusion of gases

Engel, Andreas

60

Suppression of density fluctuations in a quantum degenerate Fermi gas.  

PubMed

We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10?000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems. PMID:20867822

Sanner, Christian; Su, Edward J; Keshet, Aviv; Gommers, Ralf; Shin, Yong-Il; Huang, Wujie; Ketterle, Wolfgang

2010-07-23

61

The idealized quantum two-slit gedanken experiment revisited—Criticism and reinterpretation  

Microsoft Academic Search

An idealized two-slit experiment is envisaged in which the hypothetical experimental set-up is constructed in such a way as to resemble a toy model giving information about the structure of quantum space–time itself. Thus starting from a very simple equation which may be interpreted as a physical realization of Gödel’s undecidability theorem, we proceed to show that space–time is very

Mohamed Saladin El Naschie

2006-01-01

62

The Ideal Gas and Real Gas Heat Capacity of Sodium Atoms  

NASA Astrophysics Data System (ADS)

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

Biolsi, Louis

2014-10-01

63

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

64

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

NASA Astrophysics Data System (ADS)

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.

Blanco, Luis H.; Romero, Carmen M.

1995-10-01

65

A Unified Theory of Non-Ideal Gas Lattice Boltzmann Models  

NASA Technical Reports Server (NTRS)

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

Luo, Li-Shi

1998-01-01

66

Heat capacity of an ideal free-electron gas: A rigorous derivation  

NSDL National Science Digital Library

It is shown that the usual derivation of the heat capacity of an ideal free-electron gas is made invalid by the use of a divergent series. A plausible argument is offered to indicate that these series are asymptotic expansions which provide good approximations through their first few terms. The usual procedure is modified by the replacement of an infinite series by its first two terms plus a remainder whose bounds are estimated as being negligible to the accuracy required; a rigorous derivation of the well-known temperature dependence of the electronic heat capacity of an ideal Fermi gas results.

Weinstock, Robert

2011-08-30

67

Student understanding of the ideal gas law, Part I: A macroscopic perspective  

NSDL National Science Digital Library

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.

Kautz, Christian H.; Heron, Paula R.; Loverude, Michael E.; Mcdermott, Lillian C.

2012-07-12

68

Seeing zeros of random polynomials: quantized vortices in the ideal Bose gas  

E-print Network

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.

Yvan Castin; Zoran Hadzibabic; Sabine Stock; Jean Dalibard; Sandro Stringari

2005-11-14

69

Quantized Vortices in the Ideal Bose Gas: A Physical Realization of Random Polynomials  

SciTech Connect

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.

Castin, Yvan; Hadzibabic, Zoran; Stock, Sabine; Dalibard, Jean [Laboratoire Kastler Brossel, Ecole normale superieure, 24 rue Lhomond, 75005 Paris (France); Stringari, Sandro [Laboratoire Kastler Brossel, Ecole normale superieure, 24 rue Lhomond, 75005 Paris (France); College de France, 11 place Marcelin Berthelot, 75005 Paris (France); Dipartimento di Fisica, Universita di Trento and CNR-INFM BEC Center, I-38050 Povo, Trento (Italy)

2006-02-03

70

Quantized vortices in the ideal bose gas: a physical realization of random polynomials.  

PubMed

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. PMID:16486796

Castin, Yvan; Hadzibabic, Zoran; Stock, Sabine; Dalibard, Jean; Stringari, Sandro

2006-02-01

71

Ab-Initio Calculations and Ideal Gas Thermodynamic Functions of Cyclopentadiene and Cyclopentadiene Derivatives  

Microsoft Academic Search

Structures, frequencies and energies, ideal gas thermodynamic properties and values, have been calculated for cyclopentadiene, cyclopentadienols, and a number of radicals derived from them. The necessary molecular information for these calculaions was found by ab-initio molecular orbital calculations. The gometries, vibrational frequencies and moments of inertia of 8 species are reported. In order to estimate the accuracy of the computations

Miriam Karni; Izhack Oref; Alexander Burcat

1991-01-01

72

Kinetic Models for Adiabatic Reversible Expansion of a Monatomic Ideal Gas.  

ERIC Educational Resources Information Center

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)

Chang, On-Kok

1983-01-01

73

Quantized Vortices in the Ideal Bose Gas: A Physical Realization of Random Polynomials  

Microsoft Academic Search

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

Yvan Castin; Zoran Hadzibabic; Sabine Stock; Jean Dalibard; Sandro Stringari

2006-01-01

74

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

E-print Network

Fluctuation theorem for entropy production during effusion of an ideal gas with momentum transfer December 2006; published 19 June 2007 We derive an exact expression for entropy production during effusion are presented in appendices. II. FLUCTUATION THEOREM FOR EFFUSION WITH MOMENTUM TRANSFER We begin by

Kawai, Ryoichi

75

NIST Standard Reference Database 88 NIST/TRC Ideal Gas Database  

E-print Network

#12;NIST Standard Reference Database 88 NIST/TRC Ideal Gas Database Version 2.0 Users' Guide Data of the database and to verify that the data contained therein have been selected on the basis of sound scientific that may result from errors or omissions in the database. COPYRIGHT (C) 2006 copyright by the U

Magee, Joseph W.

76

Thermal and Electrical Conductivities of a Three-Dimensional Ideal Anyon Gas with Fractional Exclusion Statistics  

NASA Astrophysics Data System (ADS)

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.

Qin, Fang; Wen, Wen; Chen, Ji-Sheng

2014-07-01

77

Ballistic and diffusive dynamics in a two-dimensional ideal gas of macroscopic chaotic Faraday waves.  

PubMed

We have constructed a macroscopic driven system of chaotic Faraday waves whose statistical mechanics, we find, are surprisingly simple, mimicking those of a thermal gas. We use real-time tracking of a single floating probe, energy equipartition, and the Stokes-Einstein relation to define and measure a pseudotemperature and diffusion constant and then self-consistently determine a coefficient of viscous friction for a test particle in this pseudothermal gas. Because of its simplicity, this system can serve as a model for direct experimental investigation of nonequilibrium statistical mechanics, much as the ideal gas epitomizes equilibrium statistical mechanics. PMID:24827228

Welch, Kyle J; Hastings-Hauss, Isaac; Parthasarathy, Raghuveer; Corwin, Eric I

2014-04-01

78

Evolution of ideal gas mixtures confined in an insulated container by two identical pistons  

NASA Astrophysics Data System (ADS)

We study the quasistatic adiabatic expansion of monatomic-diatomic ideal gas mixtures bounded by identical pistons and obtain closed form expressions for the temperature of the gas as a function of the time. We find that the temperature decreases as an inverse power of the time for large times, with the exponent as a function of the monatomic to diatomic gas ratio. The piston speeds increase from zero to a maximum value determined by the heat capacity of the gas and the masses of the pistons. Plots of the temperature and piston speed versus the logarithm of the time show points of inflection, which are interpreted as signaling the onset of steady state behavior. These points shift to later times as the monatomic to diatomic gas ratio is varied from purely monatomic to purely diatomic.

Amor, Rumelo C.; Esguerra, Jose Perico H.

2010-09-01

79

Characteristic decomposition of compressible Euler equations for a non-ideal gas in two-dimensions  

NASA Astrophysics Data System (ADS)

We consider a two-dimensional compressible Euler system for a non-ideal gas, and use the characteristic decomposition to establish that any pseudo-steady isentropic irrotational flow, adjacent to a constant state, must be a simple wave. Further, the constancy of the entropy and vorticity along the pseudo-flow characteristics extends the foregoing conclusion to full Euler system. An attention is drawn to the fact that the result is also applicable to the shallow water system as it bears a close structural resemblance with the system under study. These results are generalization of the well-known theorem on reducible equations by Courant and Friedrichs [Supersonic Flow and Shock Waves (Springer-Verlag, New York, 1999)] and a recent result on compressible Euler system for an ideal gas by Li et al. ["Simple waves and a characteristic decomposition of the two-dimensional compressible Euler equations," Commun. Math. Phys. 267, 1-12 (2006)

Zafar, M.; Sharma, V. D.

2014-09-01

80

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

SciTech Connect

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

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

2010-06-15

81

M. Bahrami ENSC 461 (S 11) Tutorial 1 1 ENSC 461 Tutorial, Week#2 Ideal Gas  

E-print Network

M. Bahrami ENSC 461 (S 11) Tutorial 1 1 ENSC 461 Tutorial, Week#2 ­ Ideal Gas Consider a rigid 343 50 5 A2 T2 P2 25 B2 T2 P2 5 #12;M. Bahrami ENSC 461 (S 11) Tutorial 1 2 Step 4: State your specific internal energies (Recall U = mu), Eq6 is obtained. #12;M. Bahrami ENSC 461 (S 11) Tutorial 1 3

Bahrami, Majid

82

Cooking Under Pressure Applying the Ideal Gas Law in the Kitchen  

NSDL National Science Digital Library

The Clarksons are making dinner for friends and decide to try out their new pressure cooker. As students read the dialogue that ensues, they learn about how the boiling point of water is directly related to external pressure, apply the ideal gas law, and relate chemical reaction rates with temperatures in addition to learning about the conservation of energy. Designed for a non-majors’ general chemistry course, the case could be extended to other disciplines, including physics, nutrition, and microbiology.

Chen, Ling; Anderson, Jennifer Y.; Wang, Diane R.

2009-01-01

83

Seeing zeros of random polynomials: quantized vortices in the ideal Bose gas  

Microsoft Academic Search

We propose a physical system allowing one to experimentally observe the\\u000adistribution of the complex zeros of a random polynomial. We consider a\\u000adegenerate, rotating, quasi-ideal atomic Bose gas prepared in the lowest Landau\\u000alevel. Thermal fluctuations provide the randomness of the bosonic field and of\\u000athe locations of the vortex cores. These vortices can be mapped to zeros of

Yvan Castin; Zoran Hadzibabic; Sabine Stock; Jean Dalibard; Sandro Stringari

2005-01-01

84

David Maloney's Physics Examples: Thermo Example 4-Work Done by Ideal Gas  

NSDL National Science Digital Library

This item is an annotated homework problem for introductory physics students relating to the amount of work done by, or on, an ideal gas. The author provides explicit explanations of the steps required to solve for net work during four stages involving isobaric and non-isobaric processes. This resource is intended to supplement classroom instruction and traditional text materials. It is part of a larger collection of similar introductory physics homework problems.

Maloney, David

2008-10-03

85

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

E-print Network

We derive an exact expression for entropy production during effusion of an ideal gas driven by momentum transfer in addition to energy and particle flux. Following the treatment in Phys. Rev. E Vol. 74, 021117 (2006), we construct a master equation formulation of the process and explicitly verify the thermodynamic fluctuation theorem, thereby directly exhibiting its extended applicability to particle flows and hence to hydrodynamic systems.

Wood, K; Kawai, R; Lindenberg, K; Wood, Kevin; Lindenberg, Katja

2006-01-01

86

Gravitationally bound ideal gas sphere in Newtonian and in Einsteinian gravity  

NASA Astrophysics Data System (ADS)

The gravitational hydrostatic equilibrium of an isothermal ideal gas with pressure proportional to density is investigated. The system is known from the literature as the singular isothermal sphere since it has infinite central density and infinite total mass. In spite of these unphysical features the system is of pedagogical interest since it allows exact mathematical treatment both within Newtonian gravity and within general relativity. The difference between these two theories is nicely illustrated.

Essén, Hanno

2014-11-01

87

Effect of the Minimal Length on the Thermodynamics of Ultra-Relativistic Ideal Fermi Gas  

NASA Astrophysics Data System (ADS)

Based on the generalized uncertainty principle, the thermodynamics of Fermi gas in high density, high pressure and high temperature are calculated. As the temperature and density increases, the energy and entropy becomes saturated and the pressure blows up without any bound. Using the conservation equation of the Robertson—Walker cosmology, we find that, when the energy exceeds the EH = ?0-1/2c2Mp, the expansion cannot be driven by the photon gas and the fermion gas. This requires some new physical mechanism related to quantum gravity, such as tachyons and dilatons.

Zhang, Xiu-Ming; Sun, Jiu-Xun; Yang, Li

2014-04-01

88

Universality of the quantum boundary layer for a Maxwellian gas  

NASA Astrophysics Data System (ADS)

For an ideal gas confined in a rectangular domain, it has been shown that the density is not homogenous even in thermodynamic equilibrium and it goes to zero within a layer near to the boundaries due to the wave character of particles. This layer has been called the quantum boundary layer (QBL). In literature, an analytical expression for the thickness of QBL has been given for only a rectangular domain since both energy eigenvalues and eigenfunctions of the Schrödinger equation can analytically be obtained for only a rectangular domain. In this study, ideal Maxwellian gases confined in spherical and cylindrical domains are considered to investigate whether the thickness of QBL is independent of the domain shape. Although the energy eigenvalues are the roots of Bessel functions and there is no analytical expression giving the roots, the thickness of QBL is expressed analytically by considering the density distributions and using some simplifications based on the numerical calculations. It is found that QBL has the same thickness for the domains of different shapes. Therefore, QBL seems to have a universal thickness independent of the domain shape for an ideal Maxwellian gas.

Firat, C.; Sisman, A.

2009-06-01

89

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

NASA Astrophysics Data System (ADS)

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.

Biswas, Shyamal; Sen, Swati; Jana, Debnarayan

2013-05-01

90

Quantum Information from Graviton-Matter Gas  

E-print Network

We present basics of conceptually new-type way for explaining of the origin, evolution and current physical properties of our Universe from the graviton-matter gas viewpoint. Quantization method for the Friedmann-Lemaitre Universe based on the canonical Hamilton equations of motion is proposed and quantum information theory way to physics of the Universe is showed. The current contribution from the graviton-matter gas temperature in quintessence approximation is discussed.

Lukasz-Andrzej Glinka

2007-07-23

91

History Dependent Quantum Random Walks as Quantum Lattice Gas Automata  

E-print Network

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.

Asif Shakeel; David A. Meyer; Peter J. Love

2014-05-05

92

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

NASA Astrophysics Data System (ADS)

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

Kaehler, G.; Wagner, A. J.

2013-06-01

93

Slippage and Boundary Layer Probed in an Almost Ideal Gas by a Nanomechanical Oscillator  

NASA Astrophysics Data System (ADS)

We measure the interaction between He4 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 >0.1×106) 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).

Defoort, M.; Lulla, K. J.; Crozes, T.; Maillet, O.; Bourgeois, O.; Collin, E.

2014-09-01

94

Analytical theory of mesoscopic Bose-Einstein condensation in an ideal gas  

SciTech Connect

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.

Kocharovsky, Vitaly V. [Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Institute of Applied Physics, Russian Academy of Science, RU-603950 Nizhny Novgorod (Russian Federation); Kocharovsky, Vladimir V. [Institute of Applied Physics, Russian Academy of Science, RU-603950 Nizhny Novgorod (Russian Federation)

2010-03-15

95

Determination of ideal-gas enthalpies of formation for key compounds:  

SciTech Connect

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.

Steele, W.V.; Chirico, R.D.; Nguyen, A.; Hossenlopp, I.A.; Smith, N.K.

1991-10-01

96

Quantum degenerate Fermi gas entanglement in optomechanics  

NASA Astrophysics Data System (ADS)

We explain the steady-state entanglement of a quantum degenerate Fermi gas with a light field inside a Fabry-Perot cavity. The logarithmic negativity, from the covariance matrix formalism in a unified framework, shows that the bi-stability parameter and the effective detuning depend explicitly on the behavior of the entanglement. Numerical experiments reveal the sensitivity of the entanglement to experimentally controlled parameters such as, the mass of the atoms, the pump rate of the cavity, the effective detuning, and the bi-stability parameters.

Asjad, Muhammad; Shahzad, Muhammad Adnan; Saif, Farhan

2013-09-01

97

Quantum Information from Graviton-Matter Gas  

E-print Network

One of main experimental datum about our Universe is presence of the Cosmic Microwave Background radiation. We present basics of conceptually new-type way for explain of the origin, evolution and today physical properties of our Universe from the CMB anisotropies viewpoint. Quantization method for the Friedmann-Lemaitre Universe based on the canonical Hamilton equations of motion is proposed and quantum information theory way to physics of the Universe is showed. Today contribution from the Graviton-Matter gas temperature in Quintessence approximation is concluded.

Glinka, L A

2007-01-01

98

Physical model for the generation of ideal resources in multipartite quantum networking  

NASA Astrophysics Data System (ADS)

We propose a physical model for generating multipartite entangled states of spin-s particles that have important applications in distributed quantum information processing. Our protocol is based on a process where mobile spins induce the interaction among remote scattering centers. As such, a major advantage lies in the management of stationary and well-separated spins. Among the generable states, there is a class of N-qubit singlets allowing for optimal quantum telecloning in a scalable and controllable way. We also show how to prepare Aharonov, W, and Greenberger-Horne-Zeilinger states.

Ciccarello, F.; Paternostro, M.; Bose, S.; Browne, D. E.; Palma, G. M.; Zarcone, M.

2010-09-01

99

The Heat Capacity of Ideal Gases  

ERIC Educational Resources Information Center

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…

Scott, Robert L.

2006-01-01

100

Validation of the Jarzynski relation for a system with strong thermal coupling: An isothermal ideal gas model  

NASA Astrophysics Data System (ADS)

We revisit the paradigm of an ideal gas under isothermal conditions. A moving piston performs work on an ideal gas in a container that is strongly coupled to a heat reservoir. The thermal coupling is modeled by stochastic scattering at the boundaries. In contrast to recent studies of an adiabatic ideal gas with a piston [R.C. Lua and A.Y. Grosberg, J. Phys. Chem. B 109, 6805 (2005); I. Bena , Europhys. Lett. 71, 879 (2005)], the container and piston stay in contact with the heat bath during the work process. Under this condition the heat reservoir as well as the system depend on the work parameter ? and microscopic reversibility is broken for a moving piston. Our model is thus not included in the class of systems for which the nonequilibrium work theorem has been derived rigorously either by Hamiltonian [C. Jarzynski, J. Stat. Mech. (2004) P09005] or stochastic methods [G.E. Crooks, J. Stat. Phys. 90, 1481 (1998)]. Nevertheless the validity of the nonequilibrium work theorem is confirmed both numerically for a wide range of parameter values and analytically in the limit of a very fast moving piston, i.e., in the far nonequilibrium regime.

Baule, A.; Evans, R. M. L.; Olmsted, P. D.

2006-12-01

101

Some integrals of motion of an ideally conducting gas in a transverse magnetic field  

Microsoft Academic Search

A general Lagrange-Cauchy integral is obtained for the two-dimensional vortex flows of an inviscid compressible ideally conducting fluid in a transverse magnetic field. Under certain conditions the flow is governed by specified vorticity theorems and Ertel' integrals, whereas in the case of barotropism the flow is governed by the Helmholtz vorticity theorem.

V. B. Gorskii

1980-01-01

102

Universal fine structure of the specific heat at the critical ?-point for an ideal Bose gas in an arbitrary trap  

NASA Astrophysics Data System (ADS)

We analytically find the universal fine structure of the noted discontinuity in the value and/or derivative of the specific heat of an ideal Bose gas in an arbitrary trap in the whole critical region around the λ-point of the Bose–Einstein condensation. The result reveals a remarkable dependence of the λ-point structure on the trapʼs form and boundary conditions, even for a macroscopically large system. We suggest measuring this strong effect in the experiments with a controllable trap potential.

Tarasov, S. V.; Kocharovsky, Vl V.; Kocharovsky, V. V.

2014-10-01

103

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

E-print Network

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

O. M. Umurhan

2007-01-09

104

Quantum Joule-Thomson effect in a saturated homogeneous Bose gas.  

PubMed

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

Schmidutz, Tobias F; Gotlibovych, Igor; Gaunt, Alexander L; Smith, Robert P; Navon, Nir; Hadzibabic, Zoran

2014-01-31

105

Quantum Master Equation of Particle in Gas Environment  

Microsoft Academic Search

The evolution of the reduced density operatorof Brownian particle is discussed in single collision approach valid typically in low density gas environments. This is the first succesful derivation of quantum friction caused by local environmental interactions. We derive a Lindblad master equation for ?, whose generators are calculated from differential cross section of a single collision between Brownian and gas

Lajos Diosi

106

Condensation of ideal Bose gas confined in a box within a canonical ensemble  

SciTech Connect

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.

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

107

“Lateral” interaction of a supersonic underexpanded ideal-gas jet with surfaces of different shape  

Microsoft Academic Search

A numerical investigation is made of the interaction of an underexpanded jet of an inviscid and nonheat-conducting gas issuing from an axisymmetric conical nozzle with plane, cylindrical, and spherical surfaces. It is assumed that the flow turning angle for flow about a barrier is smaller than the critical angle, and subsonic regions are absent in the flow field studied. The

M. Ya. Ivanov; V. P. Nazarov

1974-01-01

108

Ideal gas in a strong gravitational field: Area dependence of entropy  

SciTech Connect

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.

Kolekar, Sanved; Padmanabhan, T. [IUCAA, Pune University Campus, Ganeshkhind, Pune 411007 (India)

2011-03-15

109

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

NSDL National Science Digital Library

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

Huguet, Jesse; Taylor, Robert; Woodbury, Keith

2011-05-09

110

Quantum memory in warm rubidium vapor with buffer gas  

E-print Network

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.

Mark Bashkansky; Fredrik K. Fatemi; Igor Vurgaftman

2011-12-02

111

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

E-print Network

Tc. Assuming that the degeneracy factor g = 1, one has: Tc = 3.31planckover2pi1 2 mn 2/3, (1.2) where n is the number density of the gas. Below the critical temperature the mean number of atoms ?n0 with the zero momentum p = 0 (the condensed atoms... of the operator ?nk = ?a?k?ak giving the number of atoms in the single-particle state. They obey the usual commutation relationships: [?ap,?a?k] = ?p,k, [?ak,?ap] = 0, [?a?p,?a?k] = 0. (1.26) BEC occurs when the mean number of atoms ?n0 of a particular single...

Dorfman, Konstantin Evgenievich

2009-05-15

112

Quantum Control of Molecular Gas Hydrodynamics  

NASA Astrophysics Data System (ADS)

We demonstrate that strong impulsive gas heating or heating suppression at standard temperature and pressure can occur from coherent rotational excitation or deexcitation of molecular gases using a sequence of nonionizing laser pulses. For the case of excitation, subsequent collisional decoherence of the ensemble leads to gas heating significantly exceeding that from plasma absorption under the same laser focusing conditions. In both cases, the macroscopic hydrodynamics of the gas can be finely controlled with ˜40 fs temporal sensitivity.

Zahedpour, S.; Wahlstrand, J. K.; Milchberg, H. M.

2014-04-01

113

Observation of Fermi surface deformation in a dipolar gas: a quantum nematic phase in the ultracold regime  

E-print Network

The deformation of a Fermi surface is a fundamental phenomenon leading to a plethora of exotic quantum phases with broken symmetries. Understanding these phases, which play crucial roles in a wealth of systems, is a major challenge in condensed matter physics. Here, we report on the observation of a Fermi surface deformation in a quantum gas of erbium atoms. The deformation is triggered by the strong magnetic dipole-dipole interaction among erbium atoms. We demonstrate that the Fermi surface deformation is tunable via an external trapping potential. Our work shows that the ground state of a dipolar Fermi gas is a nematic phase and that a dipolar Fermi gas provides an ideal clean system for exploring a nematic phase in a highly controlled manner.

Aikawa, K; Frisch, A; Mark, M; Ravensbergen, C; Ferlaino, F

2014-01-01

114

Thermal and Transport Properties of a Nonrelativistic Quantum Gas Interacting Through a Delta-Shell Potential  

NASA Astrophysics Data System (ADS)

This work extends the seminal work of Gottfried on the two-body quantum physics of particles interacting through a delta-shell potential to many-body physics by studying a system of nonrelativistic particles when the thermal De-Broglie wavelength of a particle is larger than the range of the potential and the density is such that average distance between particles is larger than the above range. The ability of the delta-shell potential to reproduce some basic properties of the deuteron are examined. Relations for moments of bound-states are derived. The virial expansion is used to calculate the first quantum correction to the ideal gas pressure in the form of the second virial coefficient. Additionally, all thermodynamical functions are calculated up to the first-order quantum corrections. For small departures from equilibrium, the net flows of mass, energy and momentum, characterized by the coefficients of diffusion, thermal conductivity and shear viscosity, respectively, are calculated. Properties of the gas are examined for various values of physical parameters including the case of infinite scattering length when the unitary limit is achieved.

Postnikov, Sergey; Prakash, Madappa

2013-10-01

115

Gas of wormholes in Euclidean quantum field theory  

E-print Network

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

Savelova, E P

2012-01-01

116

Quantum Lattice-Gas Representation of the Dirac Equation.  

National Technical Information Service (NTIS)

This paper reports explicit quantum lattice-gas unitary matrix representations for the 1D and 2D Dirac equations, and the 1D, 2D, and 3D Weyl equations. It also clarifies some algorithms and results introduced in Bialynivki-Birula 1994 and Myer 1996. Most...

G. T. Fairley

2002-01-01

117

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

NASA Astrophysics Data System (ADS)

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.

Beau, Mathieu; Savoie, Baptiste

2014-05-01

118

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

SciTech Connect

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

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

1993-09-01

119

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

ERIC Educational Resources Information Center

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…

Yu, Anne

2010-01-01

120

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

NASA Astrophysics Data System (ADS)

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

Trefzger, Christian; Castin, Yvan

2014-09-01

121

Interacting modified Chaplygin gas in loop quantum cosmology  

E-print Network

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.

Mubasher Jamil; Ujjal Debnath

2011-02-14

122

Universal scaling in the statistics and thermodynamics of a Bose-Einstein condensation of an ideal gas in an arbitrary trap  

NASA Astrophysics Data System (ADS)

We analytically calculate the critical phenomena of a Bose-Einstein condensation of an ideal gas in an arbitrary trap with any mesoscopic or macroscopic number of particles and find all universality classes of the system's statistics and thermodynamics. In particular, we find analytically the universal fine structure of the famous discontinuity in the value or/and derivative of the specific heat in the critical region around the ? point.

Tarasov, S. V.; Kocharovsky, Vl. V.; Kocharovsky, V. V.

2014-09-01

123

Quantum Simulation using Next Generation Degenerate Fermi Gas Apparatus  

NASA Astrophysics Data System (ADS)

Ultracold neutral atoms in optical lattices are a perfect toy model to simulate and study Hubbard model physics relevant to high temperature superconductivity and other exotic phases of matter. We present the design and construction of a novel apparatus to study these exciting condensed matter systems. We also investigate the viability of a various transport schemes to transport a quantum-degenerate Fermi gas of ultracold lithium atoms into a Science Chamber. The high optical access of the science chamber permits innovative probing and manipulation of BECs.

Wooley-Brown, Kate; Huber, Florian; Setiawan, Widagdo; Greiner, Markus

2010-03-01

124

Equation of state and ideal-gas heat capacity of a gaseous mixture of 1,1,1,2-tetrafluoroethane, pentafluoroethane, and difluoromethane  

SciTech Connect

The authors present the gas-phase equation of state and ideal-gas heat capacity of a ternary mixture of 1,1,1,2-tetrafluoroethane (35%), pentafluoroethane (30%), and difluoromethane (35%) for temperatures between 260 and 453 K and pressures between 0.05 and 7.7 MPa. These results were based on two very different measurement techniques. The first technique measured the gas density of the mixture in a Burnett apparatus from 313 to 453 K and from 0.2 to 7.7 MPa. The second technique deduced the gas density and ideal-gas heat capacity from high-accuracy speed-of-sound measurements in the mixture at temperatures between 260 and 400 K and at pressures between 0.05 and 1.0 MPa. The data from the two techniques were analyzed together to obtain an equation of state that reproduced the densities from the Burnett technique with a fractional RMS deviation of 0.038%, and it also reproduced the sound speeds with a fractional RMS deviation of 0.003%. Finally, the results are compared to a predictive model based on the properties of the pure fluids.

Hurly, J.J.; Schmidt, J.W.; Gillis, K.A. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1997-05-01

125

Quintessence and (anti-)Chaplygin gas in loop quantum cosmology  

SciTech Connect

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.

Lamon, Raphael; Woehr, Andreas J. [Institut fuer Theoretische Physik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany)

2010-01-15

126

Umklapp superradiance with a collisionless quantum degenerate Fermi gas.  

PubMed

The quantum dynamics of the electromagnetic light mode of an optical cavity filled with a coherently driven Fermi gas of ultracold atoms strongly depends on the geometry of the Fermi surface. Superradiant light generation and self-organization of the atoms can be achieved at low pumping threshold due to resonant atom-photon umklapp processes, where the fermions are scattered from one side of the Fermi surface to the other by exchanging photon momenta. The cavity spectrum exhibits sidebands that, despite strong atom-light coupling and cavity decay, retain narrow linewidth, due to absorptionless transparency windows outside the atomic particle-hole continuum and the suppression of broadening and thermal fluctuations in the collisionless Fermi gas. PMID:24765951

Piazza, Francesco; Strack, Philipp

2014-04-11

127

Quantum control of I2 in the gas phase and in condensed phase solid Kr matrix  

E-print Network

into account using both exact quantum dynamics and nearly classical theory. For the condensed phase, since control is indeed possible in con- densed phases. There are two paradigms for quantum control: a dynamicQuantum control of I2 in the gas phase and in condensed phase solid Kr matrix Christopher J

Apkarian, V. Ara

128

Fluid dynamics of gas exchange in high-frequency oscillatory ventilation: in vitro investigations in idealized and anatomically realistic airway bifurcation models.  

PubMed

The objective of this work is to develop understanding of the local fluid dynamic mechanisms that underpin gas exchange in high-frequency oscillatory ventilation (HFOV). The flow field during HFOV was investigated experimentally using particle image velocimetry in idealized and realistic models of a single bifurcation. Results show that inspiratory and expiratory fluid streams coexist in the airway at flow reversal, and mixing between them is enhanced by secondary flow and by vortices associated with shear layers. Unsteady flow separation and recirculation occurs in both geometries. The magnitude of secondary flow is greater in the realistic model than in the idealized model, and the structure of secondary flow is quite different. However, other flow structures are qualitatively similar. PMID:18785010

Heraty, Kevin B; Laffey, John G; Quinlan, Nathan J

2008-11-01

129

SnO2 quantum dots and quantum wires: controllable synthesis, self-assembled 2D architectures, and gas-sensing properties.  

PubMed

SnO2 quantum dots (QDs) and ultrathin nanowires (NWs) with diameters of approximately 0.5-2.5 and approximately 1.5-4.5 nm, respectively, were controllably synthesized in a simple solution system. They are supposed to be ideal models for studying the continuous evolution of the quantum-confinement effect in SnO2 1D --> 0D systems. The observed transition from strong to weak quantum confinement in SnO2 QDs and ultrathin NWs is interpreted through the use of the Brus effective-mass approximation and the Nosaka finite-depth well model. Photoluminescence properties that were coinfluenced by size effects, defects (oxygen vacancies), and surface capping are discussed in detail. With the SnO2 QDs as building blocks, various 2D porous structures with ordered hexagonal, distorted hexagonal, and square patterns were prepared on silicon-wafer surfaces and exhibited optical features of 2D photonic crystals and enhanced gas sensitivity. PMID:18715007

Xu, Xiangxing; Zhuang, Jing; Wang, Xun

2008-09-17

130

Suppression of the quantum-mechanical collapse by repulsive interactions in a quantum gas  

SciTech Connect

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.

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

131

Quantum-electrodynamical parametric instability in the incoherent photon gas.  

PubMed

We present a theory for the quantum-electrodynamical (QED) parametric scattering instability of an intense photon pulse in an incoherent radiation background. The pump electromagnetic (EM) wave can decay into a scattered daughter EM wave and an acousticlike wave due to the QED vacuum polarization nonlinearity. By a linear instability analysis we obtain a nonlinear dispersion relation for the growth rate of the scattering instability. The nonlinear QED scattering instability can give rise to the exchange of orbital angular momentum between intense Laguerre-Gaussian mode photon pulses and the two daughter waves, which may be a useful method to detect the highly energetic photon gases existing in the vicinity of rotating dense bodies in the Universe, such as pulsars and magnetars. The observation of the scattered waves may reveal information about the twisted acoustic waves in the incoherent photon gas. PMID:23496629

Wang, Yunliang; Shukla, P K; Eliasson, B

2013-02-01

132

Observational constraints of modified Chaplygin gas in loop quantum cosmology  

NASA Astrophysics Data System (ADS)

We have considered the FRW universe in loop quantum cosmology (LQC) model filled with the dark matter (perfect fluid with negligible pressure) and the modified Chaplygin gas (MCG) type dark energy. We present the Hubble parameter in terms of the observable parameters ? m0, ? x0 and H 0 with the redshift z and the other parameters like A, B, C, and ?. From the Stern data set (12 points), 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 BAO and CMB observations, we have also obtained the bounds of the parameters ( B, C) by fixing some other parameters ? and A. From the best fit of the distance modulus ?( z) for our theoretical MCG model in LQC, we concluded that our model is in agreement with the Union2 sample data.

Chakraborty, Shuvendu; Debnath, Ujjal; Ranjit, Chayan

2012-08-01

133

Universal quantum viscosity in a unitary Fermi gas.  

PubMed

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

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

2011-01-01

134

Quantum lattice-gas model for the Burgers equation  

Microsoft Academic Search

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

Jeffrey Yepez

2000-01-01

135

Universal Quantum Viscosity in a Unitary Fermi Gas  

NASA Astrophysics Data System (ADS)

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

Cao, Chenglin

136

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

E-print Network

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.

Hiromi Kaneko; Akihiro Tohsaki; Atsushi Hosaka

2012-05-02

137

Thermodynamics of Quantum Ultra-Cold Neutron Gas under Gravity of the Earth  

NASA Astrophysics Data System (ADS)

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.

Kaneko, H.; Tohsaki, A.; Hosaka, A.

2012-09-01

138

Quantum forces of a gas confined in nano structures  

NASA Astrophysics Data System (ADS)

In nano domains, thermodynamic properties of gases considerably differ from those in macro domains. One of the reasons for this difference is the quantum size effects, which become important when the thermal de Broglie wavelength of particles is not negligible in comparison with domain size. In this study, it is shown that quantum forces may appear in gases confined in nano structures due to the quantum boundary layer caused by quantum size effects. In the case of experimental verification of these quantum forces, a macroscopic manifestation of the effect of the quantum boundary layer on the thermodynamic behavior of gases can be confirmed.

Firat, Coskun; Sisman, Altug

2013-04-01

139

Sex Education and Ideals  

ERIC Educational Resources Information Center

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…

de Ruyter, Doret J.; Spiecker, Ben

2008-01-01

140

COVER IMAGE A quantum gas trapped in an optical  

E-print Network

Quantum computation: Honesty test Tomoyuki Morimae 694 Ultracold atoms: An exotic quantum object Ennio­Gordon 697 Quantum information: From bits to solids Renato Renner LETTERS 699 Unusual stable trapping-energy-gap oxide topological insulator based on the superconductor BaBiO3 Binghai Yan, Martin Jansen and Claudia

Loss, Daniel

141

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

E-print Network

study the so-called canonical ensemble problem. It describes, in some sense, an intermediate situation as com- pared with the microcanonical ensemble and the grand- canonical ensemble. In the microcanonical ensemble, the gas is completely isolated, E...%n0 2nl~nk11 !pn0 ,$ . . . ,nl21, . . . ,nk11, . . . %n0# 1hkl@nl~nk11 !pn0 ,$nk%n0 2~nl11 !nkpn0 ,$ . . . ,nl11, . . . ,nk21, . . . %n0#% 2k ($nk%n0 (k8.0 @~hk811 !~n011 !nk8pn0 ,$nk%n0 2~hk811 !n0~nk811 !pn021,$nk1dk ,k8%n021 1hk8n0~nk811 !pn0...

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

2000-01-01

142

Construction of a quantum gas microscope for fermionic atoms  

E-print Network

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 ...

Ramasesh, Vinay (Vinay V.)

2013-01-01

143

a Quantum Monte Carlo Study of the Two-Dimensional Electron Gas  

Microsoft Academic Search

Quantum Monte Carlo has recently made great progress as a computational tool for quantum many-body systems. We have extended previous Monte Carlo methods to study both ground state and excited states of the two-dimensional electron gas. For ground state properties we have used variational and fixed-node diffusion Monte Carlo methods, the latter of which is a nearly exact method for

Yongkyung Kwon

1994-01-01

144

Observation of quantum-measurement backaction with an ultracold atomic gas  

E-print Network

Current research on micro-mechanical resonators strives for quantum-limited detection of the motion of macroscopic objects. Prerequisite to this goal is the observation of measurement backaction consistent with quantum metrology limits. However, thermal noise presently dominates measurements and precludes ground-state preparation of the resonator. Here we establish the collective motion of an ultracold atomic gas confined tightly within a Fabry-Perot optical cavity as a system for investigating the quantum mechanics of macroscopic bodies. The cavity-mode structure selects a single collective vibrational mode that is measured by the cavity's optical properties, actuated by the cavity optical field, and subject to backaction by the quantum force fluctuations of this field. Experimentally, we quantify such fluctuations by measuring the cavity-light-induced heating of the intracavity atomic ensemble. These measurements represent the first observation of backaction on a macroscopic mechanical resonator at the standard quantum limit.

Kater W. Murch; Kevin L. Moore; Subhadeep Gupta; Dan M. Stamper-Kurn

2007-06-07

145

Engineering Light: Quantum Cascade Lasers  

SciTech Connect

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.

Claire Gmachl

2010-03-17

146

Engineering Light: Quantum Cascade Lasers  

ScienceCinema

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.

Claire Gmachl

2010-09-01

147

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

PubMed

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

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

2009-11-01

148

Magnetic susceptibility and Landau diamagnetism of a quantum collisional Plasmas with arbitrary degree of degeneration of electronic gas  

E-print Network

The kinetic description of magnetic susceptibility and Landau diamagnetism of quantum collisional plasmas with any degeration of electronic gas is given. The correct expression of electric conductivity of quantum collisional plasmas with any degeration of electronic gas (see A. V. Latyshev and A. A. Yushkanov, Transverse electrical conductivity of a quantum collisional plasma in the Mermin approach. - Theor. and Math. Phys., V. 175(1):559-569 (2013)) is used.

Latyshev, A V

2013-01-01

149

Satyendranath Bose: Co-Founder of Quantum Statistics  

ERIC Educational Resources Information Center

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)

Blanpied, William A.

1972-01-01

150

Impurity transport through a strongly interacting bosonic quantum gas  

SciTech Connect

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.

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

151

Vortex-antivortex wavefunction of a degenerate quantum gas  

E-print Network

A mechanism of a pinning of the quantized matter wave vortices by optical vortices in a specially arranged optical dipole traps is discussed. The vortex-antivortex optical arrays of rectangular symmetry are shown to transfer angular orbital momentum and form the "antiferromagnet"-like matter waves. The separable Hamiltonian for matter waves in pancake trapping geometry is proposed and 3D-wavefunction is factorized in a product of wavefunctions of the 1D harmonic oscillator and 2D vortex-antivortex quantum state. The 2D wavefunction's phase gradient field associated via Madelung transform with the field of classical velocities forms labyrinth-like structure. The macroscopic quantum state composed of periodically spaced counter-rotating BEC superfluid vortices has zero angular momentum and nonzero rotational energy.

A. Yu. Okulov

2009-08-03

152

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

Microsoft Academic Search

The dynamics of one and two pointlike vortices in a planar quantum gas of spin-0 particles confined in an annular region is considered. New analytical and numerical solutions are found. The concept of stationarity radius, related to the doubly connected nature of the annulus, is defined. It is seen that the existence of these radii has great impact on the

Markus Lakaniemi

2007-01-01

153

Breakdown of a topological phase: Quantum phase transition in a loop gas model with tension  

Microsoft Academic Search

We discuss the stability of topological order against local perturbations by considering the effect of a magnetic field on a spin model -- the toric code -- which is in a topological phase. The model can be mapped onto a quantum loop gas where the perturbation introduces a bare loop tension. When the loop tension is small, the topological order

Simon Trebst; Philipp Werner; Matthias Troyer; Kirill Shtengel; Chetan Nayak

2007-01-01

154

BreakdownofaTopological Phase:QuantumPhaseTransitioninaLoopGasModel withTension  

Microsoft Academic Search

We study the stability of topological order against local perturbations by considering the effect of a magnetic field on a spin model—the toric code —which is in a topological phase. The model can be mapped onto a quantum loop gas where the perturbation introduces a bare loop tension. When the loop tension is small, the topological order survives. When it

Simon Trebst; Philipp Werner; Matthias Troyer; Kirill Shtengel; Chetan Nayak

2007-01-01

155

Thermoelectric properties of a two-dimensional electron gas exhibiting the quantum Hall effect  

Microsoft Academic Search

This Communication reports studies of the thermoelectric properties of a two-dimensional electron gas in the quantum Hall regime. The data are compared to theoretical predictions for the thermopower when the chemical potential lies either in the middle of a Landau level or midway between two levels. For the comparison a Gaussian broadening is assumed and a good fit to the

J. S. Davidson; E. Dan Dahlberg; A. J. Valois; G. Y. Robinson

1986-01-01

156

Chemiresistive gas sensors employing solution-processed metal oxide quantum dot films  

NASA Astrophysics Data System (ADS)

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 H2S 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 H2S gas concentration, and the sensing mechanism was discussed using the completely depletion model with a flat band diagram.

Liu, Huan; Xu, Songman; Li, Min; Shao, Gang; Song, Huaibing; Zhang, Wenkai; Wei, Wendian; He, Mingze; Gao, Liang; Song, Haisheng; Tang, Jiang

2014-10-01

157

Breakdown of a topological phase: quantum phase transition in a loop gas model with tension.  

PubMed

We study the stability of topological order against local perturbations by considering the effect of a magnetic field on a spin model--the toric code--which is in a topological phase. The model can be mapped onto a quantum loop gas where the perturbation introduces a bare loop tension. When the loop tension is small, the topological order survives. When it is large, it drives a continuous quantum phase transition into a magnetic state. The transition can be understood as the condensation of "magnetic" vortices, leading to confinement of the elementary "charge" excitations. We also show how the topological order breaks down when the system is coupled to an Ohmic heat bath and relate our results to error rates for topological quantum computations. PMID:17359006

Trebst, Simon; Werner, Philipp; Troyer, Matthias; Shtengel, Kirill; Nayak, Chetan

2007-02-16

158

Breakdown of a topological phase: Quantum phase transition in a loop gas model with tension  

E-print Network

We study the stability of topological order against local perturbations by considering the effect of a magnetic field on a spin model -- the toric code -- which is in a topological phase. The model can be mapped onto a quantum loop gas where the perturbation introduces a bare loop tension. When the loop tension is small, the topological order survives. When it is large, it drives a continuous quantum phase transition into a magnetic state. The transition can be understood as the condensation of `magnetic' vortices, leading to confinement of the elementary `charge' excitations. We also show how the topological order breaks down when the system is coupled to an Ohmic heat bath and discuss our results in the context of quantum computation applications.

Simon Trebst; Philipp Werner; Matthias Troyer; Kirill Shtengel; Chetan Nayak

2006-09-03

159

Polarized interacting exciton gas in quantum wells and bulk semiconductors J. Fernandez-Rossier and C. Tejedor  

E-print Network

Polarized interacting exciton gas in quantum wells and bulk semiconductors J. Ferna light on the exciton luminescence of GaAs quantum wells. We study the breaking of the spin degeneracy to be due to many-body interexcitonic exchange while the spin relaxation time is controlled by intraexciton

Viña, Luis

160

Multiple quantum NMR dynamics in a gas of spin-carrying molecules in fluctuating nanopores  

NASA Astrophysics Data System (ADS)

The effect of Gaussian fluctuations of nanopores filled with a gas of spin-carrying molecules ( s = 1/2) on the multiple quantum (MQ) NMR dynamics is investigated at different variances and correlation times of the fluctuations. We show that the fluctuations smooth out the evolution of MQ NMR coherence intensities which rapidly oscillate as functions of time in the absence of fluctuations. The growth and decay of the MQ coherence clusters in the fluctuating nanopore are also investigated.

Fel'dman, E. B.; Zenchuk, A. I.

2011-11-01

161

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

NASA Astrophysics Data System (ADS)

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.

Phillips, Mark C.; Taubman, Matthew S.

2013-05-01

162

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

NASA Astrophysics Data System (ADS)

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.

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

163

Quantum gases. Observation of Fermi surface deformation in a dipolar quantum gas.  

PubMed

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. PMID:25237096

Aikawa, K; Baier, S; Frisch, A; Mark, M; Ravensbergen, C; Ferlaino, F

2014-09-19

164

Dielectric environment mediated quantum screening of one dimensional electron gas  

E-print Network

Relaxing the assumption of "infinite and homogenous background" the dielectric response function of one-dimensional (1D) semiconducting nanowires embedded in a dielectric environment is calculated. It is shown that high-k (higher than semiconductor dielectric constant) dielectric environment reduces the screening by the free carriers inside the nanostructure whereas, low dielectric environment increases the Coulombic interaction between free carriers and enhances the strength of screening function. In long wavelength limit, dielectric screening and collective excitation of electron gas are found to be solely determined by the environment instead of the semiconductor. Behavior of static dielectric function is particularly addressed at a specific wavevector q=2k_F; a wavevector ubiquitously appears in charge transport in nanostructures

Aniruddha Konar; Tian Fang; Debdeep Jena

2011-02-15

165

The Raman dressed spin-1 spin-orbit coupled quantum gas  

E-print Network

The recently realized spin-orbit coupled quantum gases (Y.-J Lin {\\it et al}., Nature 471, 83-86 (2011); P. Wang {\\it et al}., PRL 109, 095301 (2012); L. W. Cheuk {\\it et al}., PRL 109, 095302 (2012)) mark a breakthrough in the cold atom community. In these experiments, two hyperfine states are selected from a hyperfine manifold to mimic a pseudospin-1/2 spin-orbit coupled system by the method of Raman dressing, which is applicable to both bosonic and fermionic gases. In this work, we show that the method used in these experiments can be generalized to create any large pseudospin spin-orbit coupled gas if more hyperfine states are coupled equally by the Raman lasers. As an example, we study in detail a quantum gas with three hyperfine states coupled by the Raman lasers, and show when the state-dependent energy shifts of the three states are comparable, triple-degenerate minima will appear at the bottom of the band dispersions, thus realizing a spin-1 spin-orbit coupled quantum gas. A novel feature of this three minima regime is that there can be two different kinds of stripe phases with different wavelengths, which has an interesting connection to the ferromagnetic and polar phases of spin-1 spinor BECs without spin-orbit coupling.

Zhihao Lan; Patrik Ohberg

2013-11-24

166

What does an ideal wall look like?  

NASA Astrophysics Data System (ADS)

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 and gas is non-dissipative. The concept of an ideal wall is discussed within the framework of kinetic theory. In particular it is shown that a non-dissipative wall must be adiabatic and does not exerts shear stresses to the gas, if the interaction of a gas atom with the wall is not influenced by the presence of other gas atoms. It follows that temperature jumps and slip will be observed at virtually all walls, although they will be negligibly small in the hydrodynamic regime (i.e., for small Knudsen numbers).

Struchtrup, H.

2008-03-01

167

Quantum State-Resolved Reactive and Inelastic Scattering at Gas-Liquid and Gas-Solid Interfaces  

NASA Astrophysics Data System (ADS)

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.

Grütter, Monika; Nelson, Daniel J.; Nesbitt, David J.

2012-06-01

168

Ideals and Category Typicality  

ERIC Educational Resources Information Center

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

Kim, ShinWoo; Murphy, Gregory L.

2011-01-01

169

Suppression of quantum collapse in an anisotropic gas of dipolar bosons  

SciTech Connect

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.

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 IL-69978 (Israel); ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, ES-08860 Castelldefels (Barcelona) (Spain)

2011-09-15

170

Interplay of disorder and interaction in electron gas on liquid helium and in quantum dots  

NASA Astrophysics Data System (ADS)

We study nontrivial effects resulting from the interplay of interactions and disorder in an electron gas. The particular systems we investigate are electrons on liquid helium and closed quantum dots. In the first part of the thesis we analyze quantum correction to the classical Drude conductance for non-degenerate electrons on the surface of liquid helium. We show that the interference of closed electron paths in this system is suppressed by an exponential cubic factor due to thermal motion of helium vapor atoms. We test our theory by a detailed comparison to experimental data which reveals that the usual exponential dephasing is also present and it is a consequence of electron-electron interaction. We also derive analytic asymptotic formulae for the conductance peak spacing distribution in closed GaAs quantum dots using Universal Hamiltonian description in conjunction with Random Matrix Theory. Our formulae are in excellent agreement with brute-force numerical simulations and should significantly simplify experimental data analysis. In addition, we find new classes of Universal Hamiltonians that are applicable to silicon MOSFETs. The main difference from the GaAs quantum dots is that in MOSFETs electrons carry a valley index that results in qualitatively different and much richer physics. As another application of Random Matrix Theory we study the fluctuations of order parameter in isotropic phase of nanodroplets in nematic liquid crystals.

Herman, Damir

171

Why Explanations Lie: Idealization in Explanation  

E-print Network

;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

Strevens, Michael

172

Hot and Cold Ideal Gases  

NSDL National Science Digital Library

The EJS Hot and Cold Ideal Gases model simulates the mixing of hot and cold two-dimensional ideal gases in a square box. This simulation can be used as part of the activity described in "The Statistical Interpretation of Entropy: An Activity" by Todd Timberlake, to be published in The Physics Teacher. In the model, one gas is initially confined to the left side of the box while the other gas is confined to the right side. An animation window shows the motion of the particles in the box, while an optional graph window plots the temperature of each side of the box, which is determined by measuring the average KE of the particles on each side. The initial number of particles and temperature on each side of the square can be changed and a button allows the user to reverse the particle velocities at any time. The user can modify this simulation if EJS is installed locally by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. EJS Hot and Cold Ideal Gases model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_entropy_HotAndColdIdealGases.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional EJS models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Timberlake, Todd

2010-07-01

173

Quantum Monte Carlo study of the three-dimensional spin-polarized homogeneous electron gas  

NASA Astrophysics Data System (ADS)

We have studied the spin-polarized three-dimensional homogeneous electron gas using the diffusion quantum Monte Carlo method, with trial wave functions including backflow and three-body correlations in the Jastrow factor, and we have used twist averaging to reduce finite-size effects. Calculations of the pair-correlation function, including the on-top pair density, as well as the structure factor and the total energy, are reported for systems of 118 electrons in the density range rs=0.5-20 a.u., and for spin polarizations of 0, 0.34, 0.66, and 1. We consider the spin resolution of the pair-correlation function and structure factor, and the energy of spin polarization. We show that a control variate method can reduce the variance when twist averaging, and we have achieved higher accuracy and lower noise than earlier quantum Monte Carlo studies.

Spink, G. G.; Needs, R. J.; Drummond, N. D.

2013-08-01

174

Cavity quantum electrodynamics with many-body states of a two-dimensional electron gas.  

PubMed

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

Smolka, Stephan; Wuester, Wolf; Haupt, Florian; Faelt, Stefan; Wegscheider, Werner; Imamoglu, Ataç

2014-10-17

175

Quantum oscillations in the kinetic energy density: Gradient corrections from the Airy gas  

NASA Astrophysics Data System (ADS)

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.

Lindmaa, A.; Mattsson, A. E.; Armiento, R.

2014-08-01

176

Exciton gas compression and metallic condensation in a single semiconductor quantum wire.  

PubMed

We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidence of metallic liquid condensation at low temperatures. First, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Second, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at n{c} approximately 1 x 10;{5} cm;{-1} and T{c} approximately 35 K, respectively. PMID:18764504

Alén, B; Fuster, D; Muñoz-Matutano, G; Martínez-Pastor, J; González, Y; Canet-Ferrer, J; González, L

2008-08-01

177

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

E-print Network

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

Markus Lakaniemi

2007-08-14

178

Quantum  

Microsoft Academic Search

All unitary representations of the quantum ``az+b'' group are found. It turns out that this quantum group is self dual i.e. all unitary representations are 'numbered' by elements of the same group. Moreover, the formula for all unitary representations involving the quantum exponential function is proven.

Malgorzata Rowicka

2001-01-01

179

Quantum \\  

Microsoft Academic Search

All unitary representations of the quantum ``az+b'' group are found. It turns\\u000aout that this quantum group is self dual i.e. all unitary representations are\\u000a'numbered' by elements of the same group. Moreover, the formula for all unitary\\u000arepresentations involving the quantum exponential function is proven.

Malgorzata Rowicka

2001-01-01

180

Life Cycle of Superfluid Vortices and Quantum Turbulence in the Unitary Fermi Gas  

E-print Network

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.

Gabriel Wlaz?owski; Aurel Bulgac; Michael McNeil Forbes; Kenneth J. Roche

2014-04-03

181

Self-similar solution of cylindrical shock wave propagation in a rotational axisymmetric mixture of a non-ideal gas and small solid particles  

Microsoft Academic Search

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

Gorakh Nath

2010-01-01

182

OBTAINING LAWS OF THERMODYNAMICS FOR IDEAL GASES USING ELASTIC COLLISIONS  

E-print Network

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 collisionsOBTAINING LAWS OF THERMODYNAMICS FOR IDEAL GASES USING ELASTIC COLLISIONS STEPHEN MONTGOMERY

Montgomery-Smith, Stephen

183

Common physical mechanism for integer and fractional quantum Hall effects  

E-print Network

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 $\

Jianhua wang; Kang Li; Shuming Long; Yi Yuan

2011-07-05

184

Eulerian and Newtonian dynamics of quantum particles  

NASA Astrophysics Data System (ADS)

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.

Rashkovskiy, S. A.

2013-06-01

185

Ideal proportional navigation  

NASA Astrophysics Data System (ADS)

Proportional navigation has been proved to be a useful guidance technique in several surface-to-air and air-to-air homing systems for interception of airborne targets. Besides the familiar pure, true, and generalized proportional navigation guidance laws, a new guidance scheme, named ideal proportional navigation with commanded acceleration applied in the direction normal to the relative velocity between interceptor and target, is presented. In this study, the closed-form solutions of ideal proportional navigation are completely derived for maneuvering and non-maneuvering target and some important characteristics related to the system performance are introduced and investigated. Under this scheme, the capture criterion is related to the effective proportional navigation constant only, no matter what the initial condition and target maneuver are. With some more cost of energy consumption, this new guidance scheme has a larger capture area and is much more effective than previous ones.

Yuan, Pin-Jar; Chern, Jeng-Shing

186

Breakdown of a Topological Phase: Quantum Phase Transition in a Loop Gas Model with Tension Simon Trebst,1  

E-print Network

state. The transition can be understood as the condensation of ``magnetic'' vortices, leadingBreakdown of a Topological Phase: Quantum Phase Transition in a Loop Gas Model with Tension Simon the stability of topological order against local perturbations by considering the effect of a magnetic field

Trebst, Simon

187

Finite-Temperature Pairing Gap of a Unitary Fermi Gas by Quantum Monte Carlo Calculations  

SciTech Connect

We calculate the one-body temperature Green's (Matsubara) function of the unitary Fermi gas via quantum Monte Carlo, and extract the spectral weight function A(p,omega) using the methods of maximum entropy and singular value decomposition. From A(p,omega) we determine the quasiparticle spectrum, which can be accurately parametrized by three functions of temperature: an effective mass m*, a mean-field potential U, and a gap DELTA. Below the critical temperature T{sub c}=0.15epsilon{sub F} the results for m*, U, and DELTA can be accurately reproduced using an independent quasiparticle model. We find evidence of a pseudogap in the fermionic excitation spectrum for temperatures up to T*{approx_equal}0.20{epsilon}{sub F}>T{sub c}.

Magierski, Piotr; Wlazlowski, Gabriel [Faculty of Physics, Warsaw University of Technology, ulica Koszykowa 75, 00-662 Warsaw (Poland); Bulgac, Aurel; Drut, Joaquin E. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States)

2009-11-20

188

Fermi-edge superfluorescence from a quantum-degenerate electron-hole gas  

PubMed Central

Nonequilibrium can be a source of order. This rather counterintuitive statement has been proven to be true through a variety of fluctuation-driven, self-organization behaviors exhibited by out-of-equilibrium, many-body systems in nature (physical, chemical, and biological), resulting in the spontaneous appearance of macroscopic coherence. Here, we report on the observation of spontaneous bursts of coherent radiation from a quantum-degenerate gas of nonequilibrium electron-hole pairs in semiconductor quantum wells. Unlike typical spontaneous emission from semiconductors, which occurs at the band edge, the observed emission occurs at the quasi-Fermi edge of the carrier distribution. As the carriers are consumed by recombination, the quasi-Fermi energy goes down toward the band edge, and we observe a continuously red-shifting streak. We interpret this emission as cooperative spontaneous recombination of electron-hole pairs, or superfluorescence (SF), which is enhanced by Coulomb interactions near the Fermi edge. This novel many-body enhancement allows the magnitude of the spontaneously developed macroscopic polarization to exceed the maximum value for ordinary SF, making electron-hole SF even more “super” than atomic SF. PMID:24257510

Kim, Ji-Hee; II, G. Timothy Noe; McGill, Stephen A.; Wang, Yongrui; Wojcik, Aleksander K.; Belyanin, Alexey A.; Kono, Junichiro

2013-01-01

189

Fermi-edge superfluorescence from a quantum-degenerate electron-hole gas  

NASA Astrophysics Data System (ADS)

Nonequilibrium can be a source of order. This rather counterintuitive statement has been proven to be true through a variety of fluctuation-driven, self-organization behaviors exhibited by out-of-equilibrium, many-body systems in nature (physical, chemical, and biological), resulting in the spontaneous appearance of macroscopic coherence. Here, we report on the observation of spontaneous bursts of coherent radiation from a quantum-degenerate gas of nonequilibrium electron-hole pairs in semiconductor quantum wells. Unlike typical spontaneous emission from semiconductors, which occurs at the band edge, the observed emission occurs at the quasi-Fermi edge of the carrier distribution. As the carriers are consumed by recombination, the quasi-Fermi energy goes down toward the band edge, and we observe a continuously red-shifting streak. We interpret this emission as cooperative spontaneous recombination of electron-hole pairs, or superfluorescence (SF), which is enhanced by Coulomb interactions near the Fermi edge. This novel many-body enhancement allows the magnitude of the spontaneously developed macroscopic polarization to exceed the maximum value for ordinary SF, making electron-hole SF even more ``super'' than atomic SF.

Kim, Ji-Hee; , G. Timothy Noe, II; McGill, Stephen A.; Wang, Yongrui; Wójcik, Aleksander K.; Belyanin, Alexey A.; Kono, Junichiro

2013-11-01

190

Assembling gas-phase reaction mechanisms for high temperature inorganic systems based on quantum chemistry calculations and reaction rate theories  

NASA Astrophysics Data System (ADS)

Detailed chemical kinetic modeling based on computational quantum chemistry has been quite successful in making quantitative predictions about some systems, particularly the combustion of small hydrocarbons and certain areas of atmospheric chemistry. The gas phase chemistry of many processes in high-temperature inorganic systems, from materials synthesis to propulsion to waste incineration, could in principle be modeled with equal or greater success using detailed chemical kinetic modeling. This contribution provides examples from our own work of how computational quantum chemistry can be used in developing gas phase reaction mechanisms for modeling of high temperature materials processing. In the context of CVD of silicon from dichlorosilane, CVD of alumina from AlCl3/H2/CO2 mixtures, and particle nucleation from silane, this detailed chemical kinetic modeling has given us insight into gas phase reaction pathways that we would not likely have gained by other means.

Swihart, Mark T.

2005-02-01

191

Cavity-Enhanced Quantum-Cascade Laser-Based Instrument for Trace gas Measurements  

NASA Astrophysics Data System (ADS)

An autonomous instrument based on Off-Axis Integrated Cavity Output Spectroscopy has been successfully deployed for measurements of CO in the troposphere and tropopause onboard a NASA DC-8 aircraft. The instrument consists of a measurement cell comprised of two high reflectivity mirrors, a continuous-wave quantum-cascade laser, gas sampling system, control and data acquisition electronics, and data analysis software. The instrument reports CO mixing ratio at a 1-Hz rate based on measured absorption, gas temperature and pressure using Beer's Law. During several flights in May-June 2004 and January 2005 that reached altitudes of 41000 ft, the instrument recorded CO values with a precision of 0.2 ppbv (1-s averaging time). Despite moderate turbulence and measurements of particulate-laden airflows, the instrument operated consistently and did not require any maintenance, mirror cleaning, or optical realignment during the flights. We will also present recent development efforts to extend the instrument's capabilities for the measurements of CH4, N2O and CO in real time.

Provencal, R.; Gupta, M.; Owano, T.; Baer, D.; Ricci, K.; O'Keefe, A.

2005-12-01

192

Vinylphosphine-borane: synthesis, gas phase infrared spectroscopy, and quantum chemical vibrational calculations.  

PubMed

Both experimental and theoretical investigations are reported on the infrared spectrum of vinylphosphine-borane (CH(2)=CHPH(2) x BH(3)), a donor-acceptor complex. The gas phase infrared spectra (3500-600 cm(-1)) have been recorded at 0.5 cm(-1) resolution. This first primary alpha,beta-unsaturated phosphine-borane synthesized up to now is kinetically very unstable in the gas phase and decomposes rapidly into two fragments: the free vinylphosphine CH(2)=CHPH(2) and the monoborane BH(3) which dimerizes to form the more stable diborane B(2)H(6). Spectra of free CH(2)=CHPH(2) and B(2)H(6) compounds were also recorded to assign some vibration modes of the complex in very dense spectral regions. The analysis was completed by carrying out quantum mechanical calculations by density functional theory method at the B3LYP/6-31+G(**) level. Anharmonic frequencies and infrared intensities of the two predicted gauche and syn conformers of the vinylphosphine-borane complex were calculated in the 3500-100 cm(-1) region with the use of a variational approach, implemented in the P_ANHAR_V1.2 code. Because of the relatively weak interaction between the vinylphosphine and the monoborane, the vibrations of the complex can easily be subdivided into modes localized in the CH(2)=CHPH(2) and BH(3) moieties and into "intermolecular" modes. Localized modes are unambiguously correlated with the modes of the isolated monomers. Therefore, they are described in terms of the monomer vibrations, and the complexation shifts are defined as Delta nu = nu(complex) - nu(monomer) to make the effect of the complexation precise on each localized mode. In this objective, anharmonic frequencies and infrared intensities of the BH(3) monomer and the stable gauche and syn conformers of the free vinylphosphine were obtained at the same level of theory. In the gas phase, only the syn form of the complex was observed and assigned. All theoretically predicted frequencies and complexation shifts in magnitude and direction are in good agreement with experiment. By infrared spectroscopy assisted by quantum chemical calculations, the consequences of the complexation of an alpha,beta-unsaturated phosphine by borane on the physicochemical properties of the formed 12-atom complex have been efficiently evaluated. PMID:19071917

Khater, Brahim; Guillemin, Jean-Claude; Benidar, Abdessamad; Bégué, Didier; Pouchan, Claude

2008-12-14

193

Steric, Quantum, and Electrostatic Effects on SN2 Reaction Barriers in Gas Phase  

SciTech Connect

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

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

2010-01-01

194

Quantum chaos in ultracold collisions of gas-phase erbium atoms  

NASA Astrophysics Data System (ADS)

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.

Frisch, Albert; Mark, Michael; Aikawa, Kiyotaka; Ferlaino, Francesca; Bohn, John L.; Makrides, Constantinos; Petrov, Alexander; Kotochigova, Svetlana

2014-03-01

195

Characterization of Pb??Te?? quantum dot thin film synthesized by inert gas condensation.  

PubMed

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

Mahdy, Manal A; Mahdy, Iman A; El Zawawi, I K

2015-01-01

196

Thermodynamic properties and ideal-gas enthalpies of formation for cyclohexene, phthalan (2,5-dihydrobenzo-3,4-furan), isoxazole, octylamine, dioctylamine, trioctylamine, phenyl isocyanate, and 1,4,5,6-tetrahydropyrimidine  

SciTech Connect

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

Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.; Tasker, I.R. [National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States). IIT Research Inst.] [National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States). IIT Research Inst.

1996-11-01

197

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

E-print Network

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

198

Multiple quantum NMR dynamics of spin-12 carrying molecules of a gas in nanopores  

NASA Astrophysics Data System (ADS)

We consider the multiple quantum (MQ) NMR dynamics of a gas of spin carrying molecules in nanocavities. MQ NMR dynamics is determined by the residual dipole-dipole interactions, which are not averaged completely due to the molecular diffusion in nanopores. Since the averaged nonsecular Hamiltonian describing MQ NMR dynamics depends on only one coupling constant, this Hamiltonian commutes with the square of the total spin angular momentum Î2. We use the basis of common eigenstates of Î2 and the projection of I on the external magnetic field for investigation of MQ NMR dynamics. This approach allows us to study MQ NMR dynamics in systems consisting of several hundreds of spins. The analytical approximation of the stationary profile of MQ coherences is obtained. The analytical expressions for MQ NMR coherence intensities of the five-spin system in a nanopore are found. Numerical investigations allow us to find the dependencies of intensities of MQ coherences on their orders (the profiles of MQ coherences) in systems consisting of 600 spins and even more. It is shown that the stationary MQ coherence profile in the considered system is an exponential one.

Doronin, S. I.; Fedorova, A. V.; Fel'Dman, E. B.; Zenchuk, A. I.

2009-09-01

199

Route toward the ideal thresholdless laser  

NASA Astrophysics Data System (ADS)

We consider what happens to a laser when all incoherent processes are reduced to the minimum needed to keep emission irreversible. Specifically, we investigate the case where the vacuum Rabi frequency is larger than any decay rate in the laser except for the atomic polarization decay rate. Using a fully quantum description, we show that this laser can be made to go continuously from a regime with a well-defined threshold to the ideal thresholdless regime, where the photon statistics is always Poissonian even for arbitrarily small pump powers. We suggest how a proof-of-principles experiment can be realized in the microwave domain.

Dutra, S. M.; Woerdman, J. P.; Visser, J.; Nienhuis, G.

2002-03-01

200

The performance analysis of a micro-/nanoscaled quantum heat engine  

NASA Astrophysics Data System (ADS)

A new model of micro-/nanoscaled heat engines consisting of two thin long tubes with the same length but different sizes of cross section, which are filled up with ideal quantum gases and operated between two heat reservoirs, is put forward. The working fluid of the heat engine cycle goes through four processes, which include two isothermal processes and two isobaric processes with constant longitudinal pressure. General expressions for the power output and efficiency of the cycle are derived, based on the thermodynamic properties of confined ideal quantum gases. The influence of the size effect on the power output and efficiency is discussed. The differences between the heat engines working with the ideal Bose gas and Fermi gas are revealed. The performance of the heat engines operating at weak gas degeneracy and high temperatures is further analyzed. The results obtained are more general and significant than those in the current literature.

Guo, Juncheng; Zhang, Xiuqin; Su, Guozhen; Chen, Jincan

2012-12-01

201

Ideals of generalized matrix rings  

SciTech Connect

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

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

2011-01-31

202

Beyond the Quantum  

NASA Astrophysics Data System (ADS)

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.].

Nieuwenhuizen, Theo M.; Mehmani, Bahar; Špi?ka, Václav; Aghdami, Maryam J.; Khrennikov, Andrei Yu

2007-09-01

203

Ideal thermodynamic processes of oscillatory-flow regenerative engines will go to ideal stirling cycle?  

NASA Astrophysics Data System (ADS)

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.

Luo, Ercang

2012-06-01

204

arXiv:0904.3065v1[cond-mat.quant-gas]20Apr2009 Symmetry breaking in quantum systems: the case study of vortex nucleation  

E-print Network

is the case of a fast rotating gas, when the number of vortices exceeds the number of particles. The GSarXiv:0904.3065v1[cond-mat.quant-gas]20Apr2009 Symmetry breaking in quantum systems: the case study field theory go back to the "molecular field theory" of Curie-Weiss [1] and concern magnetic phenomena

Dalibard, Jean

205

The Ideal Strength of Diamond  

NASA Astrophysics Data System (ADS)

We present calculations of both the ideal shear and tensile strengths of diamond using pseudopotential density functional theory, within the local density approximation. Our calculations show a transition to a graphitic state under large shear stress, as has recently been seen in nanoindentation studies. We also compare the ideal shear strength with the maximum shear stress observed in diamond anvil cell experiments.

Roundy, David; Cohen, Marvin L.

2001-03-01

206

Electrostatic modulation of periodic potentials in a two-dimensional electron gas: From antidot lattice to quantum dot lattice  

SciTech Connect

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.

Goswami, Srijit; Aamir, Mohammed Ali; Shamim, Saquib; Ghosh, Arindam [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Siegert, Christoph; Farrer, Ian; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Pepper, Michael [Department of Electrical and Electronic Engineering, University College, London WC1E 7JE (United Kingdom)

2013-12-04

207

On fuzzy ideals of BL-algebras.  

PubMed

In this paper we investigate further properties of fuzzy ideals of a BL-algebra. The notions of fuzzy prime ideals, fuzzy irreducible ideals, and fuzzy Gödel ideals of a BL-algebra are introduced and their several properties are investigated. We give a procedure to generate a fuzzy ideal by a fuzzy set. We prove that every fuzzy irreducible ideal is a fuzzy prime ideal but a fuzzy prime ideal may not be a fuzzy irreducible ideal and prove that a fuzzy prime ideal ? is a fuzzy irreducible ideal if and only if ?(0) = 1 and |Im(?)| = 2. We give the Krull-Stone representation theorem of fuzzy ideals in BL-algebras. Furthermore, we prove that the lattice of all fuzzy ideals of a BL-algebra is a complete distributive lattice. Finally, it is proved that every fuzzy Boolean ideal is a fuzzy Gödel ideal, but the converse implication is not true. PMID:24892085

Meng, Biao Long; Xin, Xiao Long

2014-01-01

208

Spaces of Ideal Convergent Sequences  

PubMed Central

In the present paper, we introduce some sequence spaces using ideal convergence and Musielak-Orlicz function ? = (Mk). We also examine some topological properties of the resulting sequence spaces. PMID:24592143

Mursaleen, M.; Sharma, Sunil K.

2014-01-01

209

Sub-Poissonian Fluctuations in a 1D Bose Gas: From the Quantum Quasicondensate to the Strongly Interacting Regime  

SciTech Connect

We report on local, in situ measurements of atom number fluctuations in slices of a one-dimensional Bose gas on an atom chip setup. By using current modulation techniques to prevent cloud fragmentation, we are able to probe the crossover from weak to strong interactions. For weak interactions, fluctuations go continuously from super- to sub-Poissonian as the density is increased, which is a signature of the transition between the subregimes where the two-body correlation function is dominated, respectively, by thermal and quantum contributions. At stronger interactions, the super-Poissonian region disappears, and the fluctuations go directly from Poissonian to sub-Poissonian, as expected for a ''fermionized'' gas.

Jacqmin, Thibaut; Armijo, Julien; Bouchoule, Isabelle [Laboratoire Charles Fabry, Institut d'Optique, UMR8501 du CNRS, 91127 Palaiseau Cedex (France); Berrada, Tarik [Laboratoire Charles Fabry, Institut d'Optique, UMR8501 du CNRS, 91127 Palaiseau Cedex (France); Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1020 Vienna (Austria); Kheruntsyan, Karen V. [School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072 (Australia)

2011-06-10

210

Quantum friction  

E-print Network

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

R. Tsekov

2012-03-12

211

Quantum Friction  

NASA Astrophysics Data System (ADS)

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

Tsekov, Roumen

2012-12-01

212

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

213

The Geometry of Non-Ideal Fluids  

NASA Astrophysics Data System (ADS)

Arnold showed that the Euler equations of an ideal fluid describe geodesies on the Lie algebra of incompressible vector fields. We generalize this to fluids with dissipation and Gaussian random forcing. The dynamics is determined by the structure constants of a Lie algebra, along with inner products defining kinetic energy, Ohmic dissipation and the covariance of the forces. This allows us to construct tractable toy models for fluid mechanics with a finite number of degrees of freedom. We solve one of them to show how symmetries can be broken spontaneously.In another direction, we derive a deterministic equation that describes the most likely path connecting two points in the phase space of a randomly forced system: this is a WKB approximation to the Fokker-Plank-Kramer equation, analogous to the instantons of quantum theory. Applied to hydrodynamics, we derive a PDE system for Navier-Stokes instantons.

Rajeev, S. G.

2013-12-01

214

An ideal characterization of the Clifford operators  

NASA Astrophysics Data System (ADS)

The Clifford operators are an important and well-studied subset of quantum operations, in both the qubit and higher-dimensional qudit cases. While there are many ways to characterize this set, this paper aims to provide an ideal characterization, in the sense that it has the same characterization in every finite dimension, is characterized by a minimal set of gates, is constructive, and does not make any assumptions about non-Clifford operations or resources (such as the use of ancillas or the ability to make measurements). While most characterizations satisfy some of these properties, this appears to be the first characterization satisfying all of the above. As an application, we use these results to briefly analyze characterizations of Clifford embeddings, that is, the action of logical Clifford operations acting on qunits embedded in higher-dimensional qudits, inside the qudit Clifford framework.

Farinholt, J. M.

2014-08-01

215

Chemical dynamics in the gas phase: Time-dependent quantum mechanics of chemical reactions  

SciTech Connect

A major goal of this research is to obtain an understanding of the molecular reaction dynamics of three and four atom chemical reactions using numerically accurate quantum dynamics. This work involves: (i) the development and/or improvement of accurate quantum mechanical methods for the calculation and analysis of the properties of chemical reactions (e.g., rate constants and product distributions), and (ii) the determination of accurate dynamical results for selected chemical systems, which allow one to compare directly with experiment, determine the reliability of the underlying potential energy surfaces, and test the validity of approximate theories. This research emphasizes the use of recently developed time-dependent quantum mechanical methods, i.e. wave packet methods.

Gray, S.K. [Argonne National Laboratory, IL (United States)

1993-12-01

216

Vortex Quantum Creation and Winding Number Scaling in a Quenched Spinor Bose Gas  

SciTech Connect

Motivated by a recent experiment, we study nonequilibrium quantum phenomena taking place in the quench of a spinor Bose-Einstein condensate through the zero-temperature phase transition separating the polar paramagnetic and planar ferromagnetic phases. We derive the typical spin domain structure (correlations of the effective magnetization) created by the quench arising due to spin-mode quantum fluctuations, and we establish a sample-size scaling law for the creation of spin vortices, which are topological defects in the transverse magnetization.

Uhlmann, Michael; Schuetzhold, Ralf [Institut fuer Theoretische Physik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Fischer, Uwe R. [Eberhard-Karls-Universitaet Tuebingen, Institut fuer Theoretische Physik, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

2007-09-21

217

Vortex quantum creation and winding number scaling in a quenched spinor Bose gas.  

PubMed

Motivated by a recent experiment, we study nonequilibrium quantum phenomena taking place in the quench of a spinor Bose-Einstein condensate through the zero-temperature phase transition separating the polar paramagnetic and planar ferromagnetic phases. We derive the typical spin domain structure (correlations of the effective magnetization) created by the quench arising due to spin-mode quantum fluctuations, and we establish a sample-size scaling law for the creation of spin vortices, which are topological defects in the transverse magnetization. PMID:17930483

Uhlmann, Michael; Schützhold, Ralf; Fischer, Uwe R

2007-09-21

218

The Stoicism of the Ideal Orator: Cicero's Hellenistic Ideal  

Microsoft Academic Search

This reading of De Oratore uses Stoic philosophy and rhetoric to trace out a complex Ciceronian theory of rhetoric. Cicero rejected Stoic style, labeling it as meager and unpersuasive. However, he coalesced Stoic philosophy with Greek rhetoric to produce his ideal orator. Cicero described eloquentia as natural public speech that was distinctive to every person, yet he also explained how

Brandon Inabinet

2011-01-01

219

Ideals and flexibility in close relationships  

E-print Network

their ideal standards. Self-perceptions were positively related to conceptions of an ideal partner, and positive self-perceptions were also related to being less flexible with respect to ideal standards. Further, perceiving a dating partner as more closely...

Campbell, Lorne John

2012-06-07

220

Towards high-precision isotopic analysis of CO2 from ice-core gas bubbles using quantum cascade laser spectroscopy  

NASA Astrophysics Data System (ADS)

The paleo-climate archive provided by gas stored in bubbles in the ice provides a powerful means to study the ~40% increase in the atmospheric CO2 concentration between glacial and interglacial climates, in combination with numerical modeling studies, to elucidate the underlying physical mechanisms. Of particular interest is, considering the strong correlation between the carbon cycle and climate, and in light of the post-industrial revolution anthropogenic increase of the CO2 concentration. The source of the CO2 released into the atmosphere during previous deglaciations can be constrained from 13CO2 isotopic measurements on CO2 gas stored in bubbles in the ice-cores by the fact that the different CO2 reservoirs (terrestrial biosphere, oceans) and associated mechanisms (biological or physical) have different isotopic signatures. Unfortunately, conventional IRMS measurements on the small quantity of gas available are difficult, tedious, and time-consuming. We report here on the design of an alternative method based on Optical Feedback Cavity Enhanced Absorption Spectrometry (OF-CEAS) using a quantum cascade laser operating near 4.36 ?m. The aim of this instrument design is to achieve the measurement of the 13C/12C isotopic ratio (?13C) with a precision better than 0.05 ‰ on small quantities of the trapped atmospheric CO2. We describe the instrument and show preliminary results.

Shah, Miral; Gorrotxategi Carbajo, Paula; Kerstel, Erik; Chappellaz, Jerome

2013-04-01

221

Critical Thinking and Educational Ideal  

ERIC Educational Resources Information Center

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…

Liu, Qian

2007-01-01

222

Carbon Nanomaterials: The Ideal Interconnect  

E-print Network

-dimensional allotropes of carbon, known as carbon nanomaterials, have extraordinary physical properties becauseCarbon Nanomaterials: The Ideal Interconnect Technology for Next- Generation ICs Hong Li, Chuan Xu-generation ICs. In this research, carbon nanomaterials, with their many attractive properties, are emerging

223

Lecture notes Ideal fluid mechanics  

E-print Network

Lecture notes Ideal fluid mechanics Simon J.A. Malham Simon J.A. Malham (6th Feb 2010) Maxwell by the meteorological office for weather prediction down to any application in chemical engineering you can think of and in the process learn about the subtleties of fluid mechanics and along the way see lots of interesting

Malham, Simon J.A.

224

Ideal Multipartite Secret Sharing Schemes  

NASA Astrophysics Data System (ADS)

Multipartite secret sharing schemes are those having a multipartite access structure, in which the set of participants is divided into several parts and all participants in the same part play an equivalent role. Several particular families of multipartite schemes, such as the weighted threshold schemes, the hierarchical and the compartmented schemes, and the ones with bipartite or tripartite access structure have been considered in the literature. The characterization of the access structures of ideal secret sharing schemes is one of the main open problems in secret sharing. In this work, the characterization of ideal multipartite access structures is studied with all generality. Our results are based on the well-known connections between ideal secret sharing schemes and matroids. One of the main contributions of this paper is the application of discrete polymatroids to secret sharing. They are proved to be a powerful tool to study the properties of multipartite matroids. In this way, we obtain some necessary conditions and some sufficient conditions for a multipartite access structure to be ideal.

Farràs, Oriol; Martí-Farré, Jaume; Padró, Carles

225

Computation of ideal MHD equilibria  

Microsoft Academic Search

This paper reviews two- and three-dimensional ideal MHD equilibrium codes, with particular emphasis on axisymmetric toroidal calculations. In this case (Tokamak geometry), the equilibrium problem can be formulated in three essentially different ways, depending on whether (I) mirror currents in a copper shell or (II) given, applied external currents provide for balancing of the hoop force and shaping of the

K. Lackner

1976-01-01

226

TIMSS & PIRLS An Ideal Opportunity--  

E-print Network

TIMSS & PIRLS An Ideal Opportunity-- Assessing TIMSS and PIRLS Together at the Fourth Grade to assess their fourth grade students in three fundamental curricular areas--mathematics, science--assessed their same fourth grade students in reading, mathematics, and science. In response, the TIMSS & PIRLS

Huang, Jianyu

227

Suppression of quantum collapse in an anisotropic gas of dipolar bosons  

Microsoft Academic Search

In recent work [Sakaguchi and Malomed, Phys. Rev. APLRAAN1050-294710.1103\\/PhysRevA.83.013607 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 -(U0\\/2)r-2 was proposed, based on the replacement of the linear Schrödinger equation by the Gross-Pitaevskii (GP) equation with the repulsive cubic term. The model applies to a

Hidetsugu Sakaguchi; Boris A. Malomed

2011-01-01

228

Photoacoustic trace gas sensing with mid-IR quantum cascade lasers  

Microsoft Academic Search

We report on the realization of an optoacoustic sensor based on mid-infrared quantum-cascade lasers (QCLs) for the detection of nitric oxide (NO) and formaldehyde (CH2O). A resonant photoacoustic cell equipped with 4 electret microphones was excited in its first longitudinal mode by the modulated laser light. A detection limit of 150 parts in 109 (ppbv) for NO and CH2O was

Angela Elia; Vincenzo Spagnolo; C. Di Franco; P. M. Lugara; G. Scamarcio

2009-01-01

229

The Gas Sensing Mechanism of the Low-Dimension Carbon Composites with Metal Oxide Quantum Dots  

NASA Astrophysics Data System (ADS)

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.

Ma, Hui; Zhou, Weiman; Yuan, Wu; Jie, Zheng; Liu, Hongzhong; Li, Xin.

230

Initialization and readout of spin chains for quantum information transport  

E-print Network

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 ...

Kaur, Gurneet

231

Quantum-tunneling dynamics of a spin-polarized Fermi gas in a double-well potential  

SciTech Connect

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.

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

232

QUALITAS: A mid-infrared spectrometer for sensitive trace gas measurements based on quantum cascade lasers in CW operation  

NASA Astrophysics Data System (ADS)

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).

Kormann, R.; Königstedt, R.; Parchatka, U.; Lelieveld, J.; Fischer, H.

2005-07-01

233

Molecular structure of 1,3-dimethoxybenzene as studied by gas-phase electron diffraction and quantum chemical calculations  

NASA Astrophysics Data System (ADS)

The molecular structure and conformational properties of 1,3-dimethoxybenzene (1,3-DMB) have been studied by gas-phase electron diffraction (GED) and quantum chemical calculations (B3LYP and MP2 methods with 6-31G(d,p) and cc-pVTZ basis sets). The differences between geometrical parameters were constrained at values calculated at B3LYP/cc-pVTZ and MP2/cc-pVTZ levels. Quantum chemical calculations predict three stable planar conformers for 1,3-DMB: syn-anti ( Cs symmetry), anti-anti ( C2v symmetry), and syn-syn ( C2v symmetry) with abundances of about 65%, 20%, and 15%, respectively ( syn and anti describe the orientation of the O-CH 3 bonds relative to the C1-C2 and C2-C3 bonds, respectively). The GED analysis results in a mixture of 46(19)% syn-anti, 31(15)% anti-anti, and 23% syn-syn conformers, close to the contributions predicted by theoretical calculations. The experimental structural parameters agree well with results of B3LYP/cc-pVTZ and MP2/cc-pVTZ calculations.

Dorofeeva, Olga V.; Shishkov, Igor F.; Rykov, Anatoliy N.; Vilkov, Lev V.; Oberhammer, Heinz

2010-08-01

234

ENVIRONMENTAL ANALYSIS BY AB INITIO QUANTUM MECHANICAL COMPUTATION AND GAS CHROMATOGRAPHY/FOURIER TRANSFORM INFRARED SPECTROMETRY.  

EPA Science Inventory

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...

235

Ideal mixture approximation of cluster size distributions at low density  

E-print Network

We consider an interacting particle system in continuous configuration space. The pair interaction has an attractive part. We show that, at low density, the system behaves approximately like an ideal mixture of clusters (droplets): we prove rigorous bounds (a) for the constrained free energy associated with a given cluster size distribution, considered as an order parameter, (b) for the free energy, obtained by minimising over the order parameter, and (c) for the minimising cluster size distributions. It is known that, under suitable assumptions, the ideal mixture has a transition from a gas phase to a condensed phase as the density is varied; our bounds hold both in the gas phase and in the coexistence region of the ideal mixture. The present paper improves our earlier results by taking into account the mixing entropy.

S. Jansen; W. König

2011-12-20

236

Increasing the Efficiency of Ideal Solar Cells by Photon Induced Transitions at Intermediate Levels  

SciTech Connect

Recent attempts have been made to increase the efficiency of solar cells by introducing an impurity level in the semiconductor band gap. We present an analysis of such a structure under ideal conditions. We prove that its efficiency can exceed not only the Shockley and Queisser efficiency for ideal solar cells but also that for ideal two-terminal tandem cells which use two semiconductors, as well as that predicted for ideal cells with quantum efficiency above one but less than two. {copyright} {ital 1997} {ital The American Physical Society}

Luque, A.; Marti, A. [Instituto de Energia Solar, Universidad Politecnica de Madrid, 28040 Madrid (Spain)] [Instituto de Energia Solar, Universidad Politecnica de Madrid, 28040 Madrid (Spain)

1997-06-01

237

Effective medium theory of permeation through ideal polymer networks  

E-print Network

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.

Yong Wu

2007-03-02

238

OBTAINING LAWS OF THERMODYNAMICS FOR IDEAL GASES USING ELASTIC COLLISIONS  

E-print Network

that demonstrates the second law of thermo- dynamics. The second section mathematically demonstrates the adiabatic law of expansion of ideal gases. 1. The Second Law of Thermodynamics A thermally isolated container of gas B in the right half of the container. The molecules obey Newton's laws of motion, with elastic

Montgomery-Smith, Stephen

239

Representation of Ideal Magnetohydrodynamic Modes  

SciTech Connect

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 ? ? = ? X (xi X B) ensures that ? B • ? ? = 0 at a resonance, with ? labelling an equilibrium flux surface. Also useful for the analysis of guiding center orbits in a perturbed field is the representation ? ? = ? X ?B. These two representations are equivalent, but the vanishing of ? B • ?? 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 to conserve the original topology. The effect of using linearized perturbations on stability and growth rate calculations is discussed

Roscoe B. White

2013-01-15

240

Ideally Glassy Hydrogen Bonded Networks  

E-print Network

The axiomatic theory of ideally glassy networks, which has proved effective in describing phase diagrams and properties of chalcogenide and oxide glasses and their foreign interfaces, is broadened here to include intermolecular interactions in hydrogen-bonded polyalcohols such as glycerol, monosaccharides (glucose), and the optimal bioprotective hydrogen-bonded disaccharide networks formed from trehalose. The methods of Lagrangian mechanics and Maxwellian scaffolds are useful at the molecular level when bonding hierarchies are characterized by constraint counting similar to the chemical methods used by Huckel and Pauling. Whereas Newtonian molecular dynamical methods are useful for simulating large-scale interactions for times of order 10 ps, constraint counting describes network properties on glassy (almost equilibrated) time scales, which may be of cosmological order for oxide glasses, or years for trehalose. The ideally glassy network of trehalose may consist of extensible tandem sandwich arrays.

J. C. Phillips

2005-08-05

241

Ionic conductivity in a quantum lattice gas model with three-particle interactions  

NASA Astrophysics Data System (ADS)

A system of mesoscopic ions with dominant three-particle interactions is modeled by a quantum lattice liquid on the planar kagomé lattice. The two-parameter Hamiltonian contains localized attractive triplet interactions as potential energy and nearest neighbor hopping-type terms as kinetic energy. The dynamic ionic conductivity ?(?) is theoretically investigated for ‘weak hopping’ via a quantum many-body perturbation expansion of the thermal (Matsubara) Green function (current-current correlation). A simple analytic continuation and mapping of the thermal Green function provide the temporal Fourier transform of the physical retarded Green function in the Kubo formula. Substituting pertinent exact solutions for static multi-particle correlations known from previous work, Arrhenius relations are revealed in zeroth-order approximation for the dc ionic conductivity ?dc along special trajectories in density-temperature space. The Arrhenius plots directly yield static activation energies along the latter loci. Experimental possibilities relating to ?dc are discussed in the presence of equilibrium aggregation. This article is part of ‘Lattice models and integrability’, a special issue of Journal of Physics A: Mathematical and Theoretical in honour of F Y Wu's 80th birthday.

Barry, J. H.; Muttalib, K. A.; Tanaka, T.

2012-12-01

242

Diffusion Monte Carlo study of a valley-degenerate electron gas and application to quantum dots  

Microsoft Academic Search

A many-flavor electron gas (MFEG) in a semiconductor with a valley degeneracy ranging between 6 and 24 was analyzed using diffusion Monte Carlo (DMC) calculations. The DMC results compare well to an analytic expression derived by one of us [Phys. Rev. B 78, 035111 (2008)] for the total energy to within ±1% over an order of magnitude range of density,

G. J. Conduit; P. D. Haynes

2008-01-01

243

Induced quantum numbers in a (2+1)-dimensional electron gas  

Microsoft Academic Search

A gas of electrons confined to a plane is examined in both the relativistic and nonrelativistic case. Using a (0+1)-dimensional effective theory, a remarkably simple method is proposed to calculate the spin density induced by a uniform magnetic background field. The physical properties of possible fluxon excitations are determined. It is found that while in the relativistic case they can

Adrian Neagu; Adriaan M. J. Schakel

1993-01-01

244

High-In-content InGaAs quantum point contacts fabricated using focused ion beam system equipped with N2 gas field ion source  

NASA Astrophysics Data System (ADS)

Quantum point contacts (QPCs) in high-In-content InGaAs modulation-doped heterostructures fabricated using a focused ion beam (FIB) system equipped with a N2 gas field ion source (GFIS) are demonstrated. The minimum physical size of the fabricated QPCs in this study is ?30 nm, which is smaller than the typical physical size of QPCs (>50 nm) obtained by electron beam lithography and etching techniques. In addition, the fabricated QPCs are characterized electrically at low temperatures with magnetic fields. Since some of them show conductance quantization behaviors, the results indicate that the GFIS-FIB process is promising for quantum device fabrication.

Akabori, Masashi; Hidaka, Shiro; Yamada, Syoji; Kozakai, Tomokazu; Matsuda, Osamu; Yasaka, Anto

2014-11-01

245

Single layer of silicon quantum dots in silicon oxide matrix: Investigation of forming gas hydrogenation on photoluminescence properties and study of the composition of silicon rich oxide layers  

NASA Astrophysics Data System (ADS)

Structures consisting of a single layer of silicon quantum dots in a SiO 2 matrix show interesting optoelectronic properties and potential use as energy selective filters, which are a crucial component for the realization of the hot carrier solar cell. In this work single layer silicon quantum dots in SiO 2 have been realized using a magnetron sputtering technique. Quantum dots are formed by annealing of a silicon rich oxide layer deposited between a thermally grown SiO 2 layer and a sputtered SiO 2 layer. The effects of a forming gas post-hydrogenation process on the photoluminescence of the single layer of quantum dots have been investigated in order to understand the photoluminescence mechanism. It was found that for sputtered silicon quantum dots in SiO 2 matrix the photoemission mechanisms are primarily due to quantum confinement and does not strongly rely on matrix defects. In addition, physical and optical properties of several thick silicon rich oxide layers, with different chemical compositions, have been investigated in order to optimize the stoichiometry of silicon rich oxide in the single layers.

Aliberti, P.; Shrestha, S. K.; Li, Ruoyu; Green, M. A.; Conibeer, G. J.

2011-07-01

246

Relaxation explosion of a quantum degenerate exciton gas in Cu2O  

NASA Astrophysics Data System (ADS)

We present our recent experimental studies on anomalous luminescence and its connection to Bose-Einstein condensation (BEC) transition of dark excitons in a bulk semiconductor. Our sensitive and quantitative detection of this nonluminous quasi-particle using hydrogen-like internal transitions allows obtaining continuous spectra of dark excitons using a quantum cascade laser. According to quantitative measurements on the two-body inelastic collision cross section of excitons, the system needs to be cooled to sub-Kelvin temperatures. We discuss in detail our recent observation of an explosive phenomenon when the BEC criterion is satisfied (Yoshioka et al 2011 Nature Commun. 2 328) for trapped excitons using a helium-3 refrigerator, and outline a plausible scenario when the BEC transition occurs in an inelastic environment. We also discuss how to increase the condensate fraction in order to study the unique ground state of many-body electric excitations in solids.

Yoshioka, Kosuke; Kuwata-Gonokami, Makoto

2012-05-01

247

Detonation Failure in Ideal and Non-Ideal Explosives  

NASA Astrophysics Data System (ADS)

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).

Haskins, P. J.; Cook, M. D.

2007-06-01

248

Dynamics of correlations in a quasi-two-dimensional dipolar Bose gas following a quantum quench  

NASA Astrophysics Data System (ADS)

We study the evolution of correlations in a quasi-two-dimensional dipolar gas driven out of equilibrium by a sudden ramp of the interactions. On short time scales, rotonlike excitations coherently oscillate in and out of the condensate, giving rise to pronounced features in the time evolution of the momentum distribution, excited fraction, and the density-density correlation function. The evolution of these correlation functions following a quench can thus be used to probe the spectrum of the dipolar gas. We also find that density fluctuations induced by the presence of rotons following the quench, dramatically slows down the rate of spreading of correlations in the system: Near the roton instability, correlations take infinitely long to build up and show deviations from light-cone-like behavior.

Natu, Stefan S.; Campanello, L.; Das Sarma, S.

2014-10-01

249

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

NASA Astrophysics Data System (ADS)

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.

Li, Yingjie; Go, David B.

2014-09-01

250

Diffusion Monte Carlo study of a valley-degenerate electron gas and application to quantum dots  

Microsoft Academic Search

A many-flavor electron gas (MFEG) in a semiconductor with a valley degeneracy\\u000aranging between 6 and 24 was analyzed using diffusion Monte Carlo (DMC)\\u000acalculations. The DMC results compare well with an analytic expression derived\\u000aby one of us [Phys. Rev. B 78, 035111 (2008)] for the total energy to within 1%\\u000aover an order of magnitude range of density,

G. J. Conduit; P. D. Haynes

2008-01-01

251

Computational Methods for Simulating Quantum Computers  

E-print Network

This review gives a survey of numerical algorithms and software to simulate quantum computers.It covers the basic concepts of quantum computation and quantum algorithms and includes a few examples that illustrate the use of simulation software for ideal and physical models of quantum computers.

H. De Raedt; K. Michielsen

2004-06-27

252

Measuring explosive non-ideality  

SciTech Connect

The sonic reaction zone length may be measured by four methods: (1) size effect, (2) detonation front curvature, (3) crystal interface velocity and (4) in-situ gauges. The amount of data decreases exponentially from (1) to (4) with there being almost no gauge data for prompt detonation at steady state. The ease and clarity of obtaining the reaction zone length increases from (1) to (4). The method of getting the reaction zone length, , is described for the four methods. A measure of non-ideality is proposed: the reaction zone length divided by the cylinder radius. N = /R{sub o}. N = 0 for true ideality. It also decreases with increasing radius as it should. For N < 0.10, an equilibrium EOS like the JWL may be used. For N > 0.10, a time-dependent description is essential. The crystal experiment, which measures the particle velocity of an explosive-transparent material interface, is presently rising in importance. We examine the data from three experiments and apply: (1) an impedance correction that transfers the explosive C-J particle velocity to the corresponding value for the interface, and (2) multiplies the interface time by 3/4 to simulate the explosive speed of sound. The result is a reaction zone length comparable to those obtained by other means. A few explosives have reaction zones so small that the change of slope in the particle velocity is easily seen.

Souers, P C

1999-02-17

253

Representation of ideal magnetohydrodynamic modes  

SciTech Connect

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.

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

2013-02-15

254

Life's Solutions are Not Ideal  

E-print Network

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.

Bob Eisenberg

2011-05-01

255

Qualities of the ideal protégé.  

PubMed

The purpose of this paper is to share what I view as 10 important qualities of an ideal protégé. First, protégés must have a deep-seated love of learning that drives them to make the most out of the mentoring partnership. Next, protégés must be self-starters who take personal charge of their mentoring. Confidence is vital so that the junior officer can face the many challenges that lay ahead in any Army career. Careful risk taking is necessary so that the protégé can reach his or her greatest potential. Bouncing back from mistakes and failures is crucial for protégés, so they must be resilient. Ongoing enthusiasm is the fuel that sustains the mentoring relationship over time. By being open-minded, a protégé carefully considers all advice, including constructive criticism, that the mentor shares along the uphill path to wisdom. Remember that commitment is the very glue holding the mentoring relationship together. Also, protégés remain loyal to their mentors by always maintaining confidences. Most important, an ideal protégé is truly grateful for all the things that the mentor has done and repays that debt by also becoming a mentor. In closing, it is hoped that by developing these qualities, present and future protégés will get the most out of their mentoring partnerships and keep the age-old spirit of mentorship alive. PMID:20073364

Melanson, Mark A

2009-01-01

256

Programmable Quantum State Transfer  

E-print Network

A programmable quantum networks model is used in this paper for development of methods of control of a quantum state transport. These methods may be applied for a wide variety of patterns of controlled state transmission and spreading in quantum systems. The programmable perfect state transfer and quantum walk, mobile quantum (ro)bots and lattice gas automata may be described by unified way with such approach.

Alexander Yu. Vlasov

2007-08-01

257

Rheology of nearly ideal 3d foams  

E-print Network

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.

C. D. Jones; K. N. Nordstrom; D. J. Durian

2014-04-10

258

The Cracking of N-Heptane in the Gas Phase State and in the HZSM-5 Zeolite: A Quantum Molecular Dynamics Study  

SciTech Connect

Quantum molecular dynamics is used to investigate the cracking of a representative hydrocarbon of the paraffin family (n-heptane), analyzing the effects of temperature in the fragmentation of n-heptane when this compound is in the gas phase and inside a typical industrial catalyst (zeolite HZSM-5). The hydrocarbon structural and electronic features in the two environments are determined and compared. The results substantiate current views and exhibit the basic aspects in the cracking of n-heptane.

Zaragoza, I P.; Santamaria, Ruben

2002-10-10

259

The Ideal Train Timetabling Problem Toms Robenek  

E-print Network

The Ideal Train Timetabling Problem Tomás Robenek Jianghang Chen Michel Bierlaire Transport and Mobility Laboratory, EPFL May 2014 #12;The Ideal Train Timetabling Problem May 2014 Transport and Mobility Laboratory, EPFL The Ideal Train Timetabling Problem Tomás Robenek, Jianghang Chen, Michel Bierlaire

Bierlaire, Michel

260

Computing Fitting ideals of Iwasawa modules  

Microsoft Academic Search

This paper determines, in an equivariant sense, the Fitting ideals of several Iwasawa modules including the most canonical one. The connection between the modules themselves, which are usually not of finite projective dimension, and the required auxiliary modules of finite projective dimension is made rather explicit. The resulting Fitting ideals look like Stickelberger ideals, and there is a close relation

Cornelius Greither

2004-01-01

261

Recharging Our Sense of Idealism: Concluding Thoughts  

ERIC Educational Resources Information Center

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…

D'Andrea, Michael; Dollarhide, Colette T.

2011-01-01

262

A quartz enhanced photo-acoustic gas sensor based on a custom tuning fork and a terahertz quantum cascade laser.  

PubMed

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

Patimisco, Pietro; Borri, Simone; Sampaolo, Angelo; Beere, Harvey E; Ritchie, David A; Vitiello, Miriam S; Scamarcio, Gaetano; Spagnolo, Vincenzo

2014-05-01

263

Solvothermal, Chloroalkoxide-based Synthesis of Monoclinic WO3 Quantum Dots and Gas-Sensing Enhancement by Surface Oxygen Vacancies.  

PubMed

We report for the first time the synthesis of monoclinic WO3 quantum dots. A solvothermal processing at 250 °C in oleic acid of W chloroalkoxide solutions was employed. It was shown that the bulk monoclinic crystallographic phase is the stable one even for the nanosized regime (mean size 4 nm). The nanocrystals were characterized by X-ray diffraction, High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis, Fourier transform infrared and Raman spectroscopy. It was concluded that they were constituted by a core of monoclinic WO3, surface covered by unstable W(V) species, slowly oxidized upon standing in room conditions. The WO3 nanocrystals could be easily processed to prepare gas-sensing devices, without any phase transition up to at least 500 °C. The devices displayed remarkable response to both oxidizing (nitrogen dioxide) and reducing (ethanol) gases in concentrations ranging from 1 to 5 ppm and from 100 to 500 ppm, at low operating temperatures of 100 and 200 °C, respectively. The analysis of the electrical data showed that the nanocrystals were characterized by reduced surfaces, which enhanced both nitrogen dioxide adsorption and oxygen ionosorption, the latter resulting in enhanced ethanol decomposition kinetics. PMID:25211288

Epifani, Mauro; Comini, Elisabetta; Díaz, Raül; Andreu, Teresa; Genç, Aziz; Arbiol, Jordi; Siciliano, Pietro; Faglia, Guido; Morante, Joan R

2014-10-01

264

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

SciTech Connect

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.

2006-12-31

265

The ideal home hemodialysis machine.  

PubMed

Daily home hemodialysis (HD) patients have a much superior survival rate than patients on regular, 3 times a week in-center HD or on peritoneal dialysis. Present-day HD machines are unsuitable for use at home by patients. We present our concept of the ideal home HD machine that allows daily short and long HD, does all the work preparing for and cleaning up after dialysis, has an intravenous infusion system controlled by the patient, needs no systemic anticoagulation, and teaches and interacts with the patient during dialysis. To fulfill these functionalities, the dialyzer and blood tubing must be integrated with the machine and replaced less often than monthly, the machine must be capable of at least 200 L/week of hemodiafiltration, prepare all fluids necessary between and during dialyses, and all the components and fluids must be much beyond ultrapure. PMID:18638239

Kjellstrand, Carl M; Kjellstrand, Per

2008-07-01

266

Quantum Monte Carlo study of the two-dimensional electron gas in presence of Rashba interaction  

NASA Astrophysics Data System (ADS)

We introduce a variant to the diffusion Monte Carlo algorithm that can be employed to study the effects of the Rashba interaction in many-electron systems. Because of the spin-orbit nature of Rashba interaction a standard algorithm cannot be applied and therefore a specific imaginary time spin-dependent propagator has been developed and implemented following previous work developed in the framework of nuclear physics. We computed the ground-state energy of the two-dimensional electron gas at different densities for several values of the Rashba interaction strength as a function of “Rashba spin states” polarization. Comparison is given with analytically known Hartree-Fock results and for the system in absence of Coulomb interaction.

Ambrosetti, A.; Pederiva, F.; Lipparini, E.; Gandolfi, S.

2009-09-01

267

QUANTUM CRYPTOGRAPHY QUANTUM COMPUTING  

E-print Network

QUANTUM CRYPTOGRAPHY QUANTUM COMPUTING 1. Quantum cryptography : from basic principles to practical realizations. 2. Quantum computing : a conceptual revolution hard to materialize Philippe Grangier, Institut d computers, better algorithms (obviously kept secret) ? - Article by Peter Shor (1994) : a "quantum computer

Bachoc, Christine

268

Fuzzy $h$-ideals of hemirings  

E-print Network

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.

Jianming Zhan; Wies?aw A. Dudek

2006-05-28

269

Entanglement production in non-ideal cavities and optimal opacity  

E-print Network

We compute analytically the distributions of concurrence $\\bm{\\mathcal{C}}$ and squared norm $\\bm{\\mathcal{N}}$ for the production of electronic entanglement in a chaotic quantum dot. The dot is connected to the external world via one ideal and one partially transparent lead, characterized by the opacity $\\gamma$. The average concurrence increases with $\\gamma$ while the average squared norm of the entangled state decreases, making it less likely to be detected. When a minimal detectable norm $\\bm{\\mathcal{N}}_0$ is required, the average concurrence is maximal for an optimal value of the opacity $\\gamma^\\star(\\bm{\\mathcal{N}}_0)$ which is explicitly computed as a function of $\\bm{\\mathcal{N}}_0$. If $\\bm{\\mathcal{N}}_0$ is larger than the critical value $\\bm{\\mathcal{N}}_0^\\star\\simeq 0.3693\\dots$, the average entanglement production is maximal for the completely ideal case, a direct consequence of an interesting bifurcation effect.

Dario Villamaina; Pierpaolo Vivo

2012-07-19

270

Unlearning Quantum Information  

E-print Network

Quantum dynamics can be driven by measurement. By constructing measurements that gain no information, effective unitary evolution can be induced on a quantum system, for example in ancilla driven quantum computation. In the non-ideal case where a measurement does reveal some information about the system, it may be possible to "unlearn" this information and restore unitary evolution through subsequent measurements. Here we analyse two methods of quantum "unlearning" and present a simplified proof of the bound on the probability of successfully applying the required correction operators. We find that the probability of successful recovery is inversely related to the ability of the initial measurement to exclude the possibility of a state.

Daniel K. L. Oi

2014-04-15

271

PRIME IDEALS INVARIANT UNDER WINDING AUTOMORPHISMS IN QUANTUM MATRICES  

E-print Network

pullbacks of primes in the algebras R + r\\Omega R \\Gamma c ) of the winding­invariant primes of O q (M n (k of B r;c extends uniquely to a winding­invariant prime of R + r\\Omega R \\Gamma c , and that the latter primes can be uniquely expressed in the form (P +\\Omega R \\Gamma c ) + (R + r\\Omega P \\Gamma ) where P

Bigelow, Stephen

272

Practicing Identity: A Crafty Ideal?  

NASA Astrophysics Data System (ADS)

This paper focuses on the materialization of technological practices as a form of identity expression. Contextual analyses of a Mycenaean workshop area in the Late Bronze Age citadel of Tiryns (Argolis, Greece) are presented to investigate the interaction of different artisans under changing socio-political and economic circumstances. The case study indicates that although certain technological practices are often linked to specific crafts, they do not necessarily imply the separation of job tasks related to the working of one specific material versus another. Shared technological practices and activities, therefore, may be a factor in shaping cohesive group identities of specialized artisans. Since tracing artisans' identities is easier said than done on the basis of excavated materials alone, we employ the concepts of multiple chaînes opératoires combined with cross-craft interactions as a methodology in order to retrieve distinctive sets of both social and technological practices from the archaeological remains. These methodological concepts are not restricted to a specific set of steps in the production cycle, but ideally encompass reconstructing contexts of extraction, manufacture, distribution and discard/reuse for a range of artefacts. Therefore, these concepts reveal both technological practices, and, by contextualising these technological practices in their spatial layout, equally focus on social contacts that would have taken place during any of these actions. Our detailed contextual study demonstrates that the material remains when analysed in their entirety are complementary to textual evidence. In this case study they even form a source of information on palatial spheres of life about which the fragmentary Linear B texts, so far, remain silent.

Brysbaert, A.; Vetters, M.

273

Ideal amenability of module extension Banach algebras  

Microsoft Academic Search

Let A be a Banach algebra and let I be a closed two-sided ideal in A, A is A is I-weakly amenable if the first cohomology group of A with coefficients in the dual space I ? is zero; i.e., H1(A,I? )= {0}. Further, A is ideally amenable if A is I-weakly amenable for every closed two-sided ideal I in

M. Eshaghi Gordji; F. Habibian; A. Rejali

274

Quantum Computation Quantum Information  

E-print Network

Quantum Computation and Quantum Information Samuel J. Lomonaco, Jr. and Howard E. Brandt editors Searches with a Quantum Robot .............................................. 12 pages Benioff, Paul Perturbation Theory and Numerical Modeling Quantum Logic Operations with a Large of Qubits

Lomonaco Jr., Samuel J.

275

``Additive'' cooperativity of hydrogen bonds in complexes of catechol with proton acceptors in the gas phase: FTIR spectroscopy and quantum chemical calculations  

NASA Astrophysics Data System (ADS)

Experimental study of hydrogen bond cooperativity in hetero-complexes in the gas phase was carried out by IR-spectroscopy method. Stretching vibration frequencies of Osbnd H groups in phenol and catechol molecules as well as of their complexes with nitriles and ethers were determined in the gas phase using a specially designed cell. Osbnd H groups experimental frequency shifts in the complexes of catechol induced by the formation of intermolecular hydrogen bonds are significantly higher than in the complexes of phenol due to the hydrogen bond cooperativity. It was shown that the cooperativity factors of hydrogen bonds in the complexes of catechol with nitriles and ethers in the gas phase are approximately the same. Quantum chemical calculations of the studied systems have been performed using density functional theory (DFT) methods. It was shown, that theoretically obtained cooperativity factors of hydrogen bonds in the complexes of catechol with proton acceptors are in good agreement with experimental values. Cooperative effects lead to a strengthening of intermolecular hydrogen bonds in the complexes of catechol on about 30%, despite the significant difference in the proton acceptor ability of the bases. The analysis within quantum theory of atoms in molecules was carried out for the explanation of this fact.

Varfolomeev, Mikhail A.; Klimovitskii, Alexander E.; Abaidullina, Dilyara I.; Madzhidov, Timur I.; Solomonov, Boris N.

2012-06-01

276

Quantum hairs’ and entropy of the quantum isolated horizon from Chern-Simons theory  

NASA Astrophysics Data System (ADS)

We articulate the fact that the loop quantum gravity (LQG) description of the quantum macrostates of black hole horizons, modeled as quantum isolated horizons (QIHs), is completely characterized in terms of two independent integer-valued ‘quantum hairs’, viz, the coupling constant (k) of the quantum SU(2) Chern-Simons (CS) theory describing QIH dynamics, and the number of punctures (N) produced by the bulk spin network edges piercing the isolated horizon (which act as pointlike sources for the CS fields). We demonstrate that the microcanonical entropy of macroscopic (both parameters assuming very large values) QIHs can be obtained directly from the microstates of this CS theory using standard statistical mechanical methods, without having to additionally postulate the horizon as an ideal gas of punctures, or incorporate any additional classical or semiclassical input from general relativity vis-a-vis the functional dependence of the isolated horizon mass on its area, or indeed, without having to restrict to any special class of spins. Requiring the validity of the Bekenstein-Hawking area law relates these two parameters (as an equilibrium ‘equation of state’), and consequently allows the Barbero-Immirzi parameter to take any real and positive value depending on the value of k/N. The logarithmic correction to the area law obtained a decade ago by R Kaul and one of us (PM), ensues straightforwardly, with precisely the coefficient -3/2, making it a signature of the LQG approach to black hole entropy.

Majhi, Abhishek; Majumdar, Parthasarathi

2014-10-01

277

Decomposition theorem in ideal topological spaces  

NASA Astrophysics Data System (ADS)

We introduce new classes of sets called a* -I -open,A-?-I-open sets, A-pre* -I-open sets, strongly T-I -sets, A-?-T-I-sets, strongly BA -I -sets, BA -I -sets, and ??A -I -open sets in ideal topological spaces. Using these sets, to obtain decompositions of continuity in an ideal topological space.

AL-omeri, W.; Noorani, Mohd. Salmi; AL-Omari, A.

2014-06-01

278

Cubic Rashba Spin-Orbit Interaction of a Two-Dimensional Hole Gas in a Strained-Ge /SiGe Quantum Well  

NASA Astrophysics Data System (ADS)

The spin-orbit interaction (SOI) of a two-dimensional hole gas in the inversion symmetric semiconductor Ge is studied in a strained-Ge /SiGe quantum well structure. We observe weak antilocalization (WAL) in the magnetoconductivity measurement, revealing that the WAL feature can be fully described by the k-cubic Rashba SOI theory. Furthermore, we demonstrate electric field control of the Rashba SOI. Our findings reveal that the heavy hole (HH) in strained Ge is a purely cubic Rashba system, which is consistent with the spin angular momentum mj=±3/2 nature of the HH wave function.

Moriya, Rai; Sawano, Kentarou; Hoshi, Yusuke; Masubuchi, Satoru; Shiraki, Yasuhiro; Wild, Andreas; Neumann, Christian; Abstreiter, Gerhard; Bougeard, Dominique; Koga, Takaaki; Machida, Tomoki

2014-08-01

279

Cubic Rashba Spin-Orbit Interaction of a Two-Dimensional Hole Gas in a Strained-Ge/SiGe Quantum Well.  

PubMed

The spin-orbit interaction (SOI) of a two-dimensional hole gas in the inversion symmetric semiconductor Ge is studied in a strained-Ge/SiGe quantum well structure. We observe weak antilocalization (WAL) in the magnetoconductivity measurement, revealing that the WAL feature can be fully described by the k-cubic Rashba SOI theory. Furthermore, we demonstrate electric field control of the Rashba SOI. Our findings reveal that the heavy hole (HH) in strained Ge is a purely cubic Rashba system, which is consistent with the spin angular momentum m_{j}=±3/2 nature of the HH wave function. PMID:25192115

Moriya, Rai; Sawano, Kentarou; Hoshi, Yusuke; Masubuchi, Satoru; Shiraki, Yasuhiro; Wild, Andreas; Neumann, Christian; Abstreiter, Gerhard; Bougeard, Dominique; Koga, Takaaki; Machida, Tomoki

2014-08-22

280

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

E-print Network

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

Ren, Y.

281

Influence of gas source supply interruption on quantum well structure of few monolayer InP\\/In0.53Ga0.47As\\/InP grown by OMVPE  

Microsoft Academic Search

A model of asymmetric stepped quantum well affected by gas source supply interruption at the interface of extremely thin InP\\/In0.53Ga0.47As\\/InP single quantum well grown by organometallic vapor phase epitaxy (OMVPE) is developed. The energy levels in the well and the intersubband transition energies are carried out and compared to experimental data from photoreflectance spectroscopy.

W. Pecharapa; J. Nukeaw

2002-01-01

282

Converging cylindrical shocks in ideal magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

283

Predicting film genres with implicit ideals.  

PubMed

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

Olney, Andrew McGregor

2012-01-01

284

Predicting Film Genres with Implicit Ideals  

PubMed Central

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

Olney, Andrew McGregor

2013-01-01

285

Simulating quantum transport for a quasi-one-dimensional Bose gas in an optical lattice: the choice of fluctuation modes in the truncated Wigner approximation  

NASA Astrophysics Data System (ADS)

We study the effect of quantum fluctuations on the dynamics of a quasi-one-dimensional Bose gas in an optical lattice at zero temperature using the truncated Wigner approximation with a variety of basis sets for the initial fluctuation modes. The initial spatial distributions of the quantum fluctuations are very different when using a limited number of plane-wave (PW), simple-harmonic-oscillator (SHO) and self-consistently determined Bogoliubov (SCB) modes. The short-time transport properties of the Bose gas, characterized by the phase coherence in the PW basis, are distinct from those gained using the SHO and SCB basis. The calculations using the SCB modes predict greater phase decoherence and stronger number fluctuations than the other choices. Furthermore, we observe that the use of PW modes overestimates the extent to which atoms are expelled from the core of the cloud, while the use of the other modes only breaks the cloud structure slightly, which is in agreement with the experimental observations by Fertig et al (2005 Phys. Rev. Lett. 94 120403).

Xiong, Bo; Yang, Tao; Benedict, Keith A.

2013-07-01

286

On the higher Fitting ideals of Iwasawa modules of ideal class groups over real abelian fields  

E-print Network

In this paper, we study the higher Fitting ideals of the even character part of the Iwasawa modules of ideal class groups. We treat arbitary prime number p, even character \\chi and abelian extention field K/Q which is totally real and unramified at p. We construct two types of ideals C_{i,\\chi} and \\Theta^{cu}_{i,\\chi} of the Iwasawa algebra \\Lambda_\\chi by using Sinnott's circular units units. We prove that the first ideals give the upper bounds of the higher Fitting ideals, and remark some patial results on the relation between the first and second ideals and lower bounds of the higher Fitting ideals. Our result is a weak analogue of Kurihara's result, which treats the odd character part, and can be regarded as a refinement of the Iwasawa main conjecture for the even character part.

Ohshita, Tatsuya

2011-01-01

287

The direct effect of thin ideal focused adult television on young girls' ideal body figure.  

PubMed

The present study tested the direct effect of watching thin-ideal focused television aimed at (young) adults on body dissatisfaction in preadolescent girls (9-12 years old). A within-subject design was used in which the girls (N=60) were tested three times. They watched three movie clips in random order that were either focused explicitly (thin-ideal program) or indirectly (soap opera) on the thin ideal or were neutral in content. Afterwards, they filled out questionnaires concerning their body dissatisfaction. Only older preadolescent girls (11-12 years old) showed greater body dissatisfaction after watching the thin-ideal focused television clip than after watching the neutral television clip. After watching thin-ideal focused television, they desired a thinner body figure than after watching neutral television. The findings imply that watching (adult) thin-ideal television directly affects the ideal body figure in older preadolescent girls. PMID:21146480

Anschutz, Doeschka J; Spruijt-Metz, Donna; Van Strien, Tatjana; Engels, Rutger C M E

2011-01-01

288

Medical learning curves and the Kantian ideal  

PubMed Central

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

Le Morvan, P; Stock, B

2005-01-01

289

Stepwise Development from Ideal Specifications Graeme Smith  

E-print Network

Stepwise Development from Ideal Specifications Graeme Smith Software Verification Research Centre University of Queensland, Australia smith@svrc.uq.edu.au Abstract The stepwise development of a program using

Smith, Graeme

290

Simplified eigenvalue equation for ideal magnetohydrodynamics  

SciTech Connect

A change of dependent variable renders the eigenfunction equation of ideal magnetohydrodynamics more amenable to analysis of the discrete spectrum. The resulting equation and boundary value problem are discussed.

Kadish, A.

1980-09-01

291

Medical learning curves and the Kantian ideal.  

PubMed

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

Le Morvan, P; Stock, B

2005-09-01

292

Monomization of power Ideals and parking functions  

E-print Network

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

Desjardins, Craig J. (Craig Jeffrey)

2010-01-01

293

The Wendell Berry ideal: harmony and wholeness  

E-print Network

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

Kutach, Douglas Neil

2012-06-07

294

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

E-print Network

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.

Valery P. Dmitriyev

2006-02-21

295

Guiding Center Equations for Ideal Magnetohydrodynamic Modes  

SciTech Connect

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

Roscoe B. White

2013-02-21

296

The Statistical Mechanics of Ideal MHD Turbulence  

NASA Technical Reports Server (NTRS)

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

Shebalin, John V.

2003-01-01

297

Discrete nature of thermodynamics in confined ideal Fermi gases  

NASA Astrophysics Data System (ADS)

Intrinsic discrete nature in thermodynamic properties of Fermi gases appears under strongly confined and degenerate conditions. For a rectangular confinement domain, thermodynamic properties of an ideal Fermi gas are expressed in their exact summation forms. For 1D, 2D and 3D nano domains, variations of both number of particles and internal energy per particle with chemical potential are examined. It is shown that their relation with chemical potential exhibits a discrete nature which allows them to take only some definite values. Furthermore, quasi-irregular oscillatory-like sharp peaks are observed in heat capacity. New nano devices can be developed based on these behaviors.

Aydin, Alhun; Sisman, Altug

2014-06-01

298

Ideal Gas of Strings and QCD at Hadronic Scales  

E-print Network

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

Chung-I Tan

1993-01-08

299

Ionic phase transitions in non-ideal systems  

E-print Network

We construct an explicitly solvable Landau mean-field theory for volume phase transitions of confined or fixed ions driven by relative concentrations of divalent and monovalent counterions. Such phase transitions have been widely studied in ionic gels, where the mechanism relies on self-attraction or elasticity of a network. We find here that non-ideal behavior of ions in aqueous solution can in theory drive phase transitions without a self-attracting or elastic network. We represent non-ideality by a Debye-H\\"uckel-like power-law activity, or correlation free energy, and retain a mechanical self-repulsion to avoid runaway collapse due to the non-ideal term. Within this model we find a continuous line of gas-liquid-type critical points, connecting a purely monovalent, divalent-sensitive critical point at one extreme with a divalent, monovalent-sensitive critical point at the other. An alternative representation of the Landau functional handles the second case. We include a formula for electrical potential, which may be a convenient proxy for critically varying volume. Our relatively simple mean-field formulation may facilitate explorations of tunable critical sensitivity in areas such as ion detection technology and biological osmotic control.

Kyle J. Welch; Fred Gittes

2011-02-16

300

The influence of electron degeneracy on the contribution of bound states to the non-ideal hydrogen plasma EOS  

Microsoft Academic Search

An equation of state for a weakly non-ideal hydrogen plasma was developed to account for the influence of degenerate electrons on the contribution of bound states. Asymptotic expressions for the contribution were derived and compared. In this work, the reduced model EOS includes the ideal gas contribution with degenerate electrons and relativistic corrections, bound states contribution and the Coulomb interaction

Andrey N. Starostin; Vitali C. Roerich; Victor K. Gryaznov; Vladimir E. Fortov; Igor L. Iosilevskiy

2009-01-01

301

Gas-Phase Spectroscopy of Biomolecular Building Blocks  

NASA Astrophysics Data System (ADS)

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.

de Vries, Mattanjah S.; Hobza, Pavel

2007-05-01

302

Use of nitrogen as a carrier gas in LP-MOCVD for growth of GaAs AlGaAs and quantum well infrared photodetectors heterostructures  

NASA Astrophysics Data System (ADS)

In this paper the growth of GaAs and AlGaAs metal organic chemical vapor deposition (MOCVD) when nitrogen is used as carrier gas instead of hydrogen have been investigated. Properties of epilayers were studied in dependence from such parameters of epitaxy process as V/III ratio in gas phase, susceptor temperature and pressure in reactor. We fixed a conductivity types conversion from n- to p-type when mole fraction of Al in AlGaAs was increased from 19% to 67%. The abroad of conversion is near 40%. The increasing of methyl-radicals from trimethylaluminum concentration is a possible reason of this fact. To demonstrate the possibility of device structure growth by using in MOCVD nitrogen as carrier gas in first time the Quantum Well Infrared Photodetectors heterostructures have been fabricated. Some features of devices parameters are discussed. A device with mesa-structure has a dark current density of 1(DOT)10-6 A at U equals 2 V and T equals 77 K; the responsivity at U equals 2 V and 45 degree(s) angle incidence of IR-radiation was S equals 0.1 A/W ((lambda) max equals 10.7 mkm).

Zalevsky, Igor D.; Chelny, Alexander A.; Gorbylev, Vladimir A.; Avetisyan, Grachik H.; Kulikov, Vladimir B.

1995-04-01

303

Out-of-equilibrium evolution of kinetically constrained many-body quantum systems under purely dissipative dynamics  

NASA Astrophysics Data System (ADS)

We explore the relaxation dynamics of quantum many-body systems that undergo purely dissipative dynamics through non-classical jump operators that can establish quantum coherence. Our goal is to shed light on the differences in the relaxation dynamics that arise in comparison to systems evolving via classical rate equations. In particular, we focus on a scenario where both quantum and classical dissipative evolution lead to a stationary state with the same values of diagonal or "classical" observables. As a basis for illustrating our ideas we use spin systems whose dynamics becomes correlated and complex due to dynamical constraints, inspired by kinetically constrained models (KCMs) of classical glasses. We show that in the quantum case the relaxation can be orders of magnitude slower than the classical one due to the presence of quantum coherences. Aspects of these idealized quantum KCMs become manifest in a strongly interacting Rydberg gas under electromagnetically induced transparency (EIT) conditions in an appropriate limit. Beyond revealing a link between this Rydberg gas and the rather abstract dissipative KCMs of quantum glassy systems, our study sheds light on the limitations of the use of classical rate equations for capturing the non-equilibrium behavior of this many-body system.

Olmos, Beatriz; Lesanovsky, Igor; Garrahan, Juan P.

2014-10-01

304

Quest for ideal weight: costs and consequences.  

PubMed

The quest to achieve the ideal weight comes with notable costs. Dieting carries the financial costs of professional consulting, low-calorie foods, books and materials, and diet programming. Club memberships, clothing, equipment, and time all contribute to the cost of exercise. Cosmetic surgery to achieve the desired physique carries a significant financial, and sometimes psychological, burden. Women often pursue thinner bodies despite already being at a healthy weight. This pursuit is motivated primarily to enhance appearance. The ideal body portrayed in the media has stabilized in thinness, but it is becoming increasingly tubular, i.e., taller with slimmer hips and thicker waist. This ideal is presented to adult and adolescent women in their popular magazines, and to little girls with their dolls. Exercise is promoted as an optimal means to achieve the ideal physique. Young American women tend to idealize an athletic body shape, especially with upper-body muscularity. This shape can be attained only through sustained exercise and upper-body strength training. High-level exercise may be a precursor to eating disorders. Women who exercise to excess, who are highly preoccupied with weight, and who are characterized by perfectionism and an obsessive compulsive personality are at risk for eating disorders. When body weight and shape are kept in perspective and realistic goals are set, the physical, psychological, and financial costs of achieving or maintaining a healthy weight may be minimized. PMID:10449015

Lindeman, A K

1999-08-01

305

Statistical Thermodynamics of Polymer Quantum Systems  

NASA Astrophysics Data System (ADS)

Polymer quantum systems are mechanical models quantized similarly as loop quantum gravity. It is actually in quantizing gravity that the polymer term holds proper as the quantum geometry excitations yield a reminiscent of a polymer material. In such an approach both non-singular cosmological models and a microscopic basis for the entropy of some black holes have arisen. Also important physical questions for these systems involve thermodynamics. With this motivation, in this work, we study the statistical thermodynamics of two one dimensional polymer quantum systems: an ensemble of oscillators that describe a solid and a bunch of non-interacting particles in a box, which thus form an ideal gas. We first study the spectra of these polymer systems. It turns out useful for the analysis to consider the length scale required by the quantization and which we shall refer to as polymer length. The dynamics of the polymer oscillator can be given the form of that for the standard quantum pendulum. Depending on the dominance of the polymer length we can distinguish two regimes: vibrational and rotational. The first occur for small polymer length and here the standard oscillator in Schrödinger quantization is recovered at leading order. The second one, for large polymer length, features dominant polymer effects. In the case of the polymer particles in the box, a bounded and oscillating spectrum that presents a band structure and a Brillouin zone is found. The thermodynamical quantities calculated with these spectra have corrections with respect to standard ones and they depend on the polymer length. When the polymer length is small such corrections resemble those coming from the phenomenological generalized uncertainty relation approach based on the idea of the existence of a minimal length. For generic polymer length, thermodynamics of both systems present an anomalous peak in their heat capacity CV. In the case of the polymer oscillators this peak separates the vibrational and rotati onal regimes, while in the ideal polymer gas it reflects the band structure which allows the existence of negative temperatures.

Chacón-Acosta, Guillermo; Manrique, Elisa; Dagdug, Leonardo; Morales-Técotl, Hugo A.

2011-12-01

306

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

Microsoft Academic Search

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

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

2000-01-01

307

Creating, maintaining, and breaking of quantum entanglement in quantum operations  

NASA Astrophysics Data System (ADS)

We study the evolution of entanglement in quantum gates in terms of Choi-Jamiolkowski relative states negativity. SQiSW (generated by XY-interaction), CNOT and CZ gates are considered in ideal case and under amplitude and phase relaxation. In addition, we consider an important task of analyzing entanglement of "pure" noise, which is obtained by deducting an ideal gate from a noisy one.

Bogdanov, Yu. I.; Chernyavskiy, A. Yu.; Holevo, A. S.; Lukichev, V. F.; Orlikovsky, Alexander A.; Bantysh, B. I.

2013-01-01

308

Reality television and the muscular male ideal.  

PubMed

Although researchers have examined the negative effects of viewing reality television (RTV) on women's body image, this research has not been extended to men. Exploring the extent to which RTV depicts men who embody the muscular ideal may enhance our understanding of the potential influence of this media genre. We explored the extent to which RTV depicted men who embodied the muscular ideal using a quantitative content analysis. Based on binomial tests, the primary male cast members of programs airing on networks popular among young adult men during the Fall 2009 broadcast season were more muscular, with lower levels of body fat, than average U.S. men. The chest-to-waist and shoulder-to-waist ratios of these cast members did not differ as a function of program type (i.e., reality drama, endurance, and romance). Young men who view RTV programs included in the present study would be exposed to an unrepresentative muscular ideal. PMID:23523084

Dallesasse, Starla L; Kluck, Annette S

2013-06-01

309

A Two-Dimensional Electron Gas as a Sensitive Detector for Time-Resolved Tunneling Measurements on Self-Assembled Quantum Dots  

PubMed Central

A two-dimensional electron gas (2DEG) situated nearby a single layer of self-assembled quantum dots (QDs) in an inverted high electron mobility transistor (HEMT) structure is used as a detector for time-resolved tunneling measurements. We demonstrate a strong influence of charged QDs on the conductance of the 2DEG which allows us to probe the tunneling dynamics between the 2DEG and the QDs time resolved. Measurements of hysteresis curves with different sweep times and real-time conductance measurements in combination with an boxcar-like evaluation method enables us to unambiguously identify the transients as tunneling events between the s- and p-electron QD states and the 2DEG and rule out defect-related transients. PMID:20672130

2010-01-01

310

Analysis of an idealized Stirling thermocompressor  

SciTech Connect

A thermocompressor uses thermal energy to increase the pressure of a fluid without the intermediate production of mechanical work. The thermocompressor described here is essentially a cold-connected Gamma Stirling engine with the power cylinder replaced by inlet and discharge check valves. It is analyzed based on assumptions similar to those made in the analysis of an ideal Stirling engine. The analysis gives closed form predictions for thermocompressor thermal efficiency, volumetric efficiency, and non-dimensional heat input as functions of pressure and temperature ratio. It is also used to compare thermocompressor performance to that of an ideal Otto engine-driven mechanical compressor.

Kornhauser, A.A. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Mechanical Engineering

1996-12-31

311

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

E-print Network

1 Forging the Ideal Liberal LearningForging the Ideal Liberal Learning (Goals of Education, Empathy, Courage) (Toward Global Sustainability) Language Education in the 21st Century Forging lectures in 2007 2 ICT (Collaborative Learning) Komaba Active Learning Studio=KALS #12;4 1 ALESS

Miyashita, Yasushi

312

Rabindranath Tagore's Ideals of Aesthetic Education.  

ERIC Educational Resources Information Center

Rabindranath Tagore (1861-1941) was an Indian educator who established the Santiniketan schools, which replicated to a large extent the ashram or forest school of ancient India, where gurus and their pupils lived in a residential hermitage. Tagore's aesthetic ideals of education as manifested in the school at Santiniketan are discussed. (RM)

Lal, Swati

1984-01-01

313

Ideal microlenses for laser to fiber coupling  

Microsoft Academic Search

The design and fabrication of ideal microlenses for semiconductor laser to fiber coupling are reported. Properly coated for reflections, lenses of the new design can theoretically collect 100% of the radiated energy of a modal-symmetric laser source. The crucial feature is its hyperbolic shape. Microlenses fabricated directly on the end of the fiber by laser micromachining have demonstrated up to

Christopher A. Edwards; Herman M. Presby; Corrado Dragone

1993-01-01

314

Ramamurthy V. Dwivedula Ideal Institute of Technology,  

E-print Network

Ramamurthy V. Dwivedula Principal Ideal Institute of Technology, Kakinada 533 003, India e employing gears or ball-screws and indicates the play between adjacent moveable parts. Since the action of a clearance (D), and (ii) impact phenomena between the surfaces of the masses (Mm and ML). In Fig. 1, Mm

Pagilla, Prabhakar R.

315

Street Children Draw the Ideal Person.  

ERIC Educational Resources Information Center

Forty-three adolescents (11-16 years of age) attending a health care program, Project Alternatives, for "street children" in Tegucigalpa, Honduras, drew randomly assigned pictures of either the ideal man or woman, engaged in some activity. These drawings were compared to samples from adolescents in various parts of the world to assess the global…

DiCarlo, Margaret A.; And Others

316

Embedding the Schwarzschild Ideal Fluid Metric  

E-print Network

Certain semi-Riemannian metrics can be decomposed into a Riemannian part and an isochronal part. The properties of such metrics are particularly easy to visualize in a coordinate-free way, using isometric embedding. We present such an isochronal, isometric embedding of the well known Schwarzschild ideal fluid metric in an attempt to see what is happening when the pressure becomes singular.

Earnest Harrison

2007-01-11

317

Multiple citizenship: normative ideals and institutional challenges  

Microsoft Academic Search

Institutional suggestions for how to rethink democracy in response to changing state responsibilities and capabilities have been numerous and often mutually incompatible. This suggests that conceptual unclarity still reigns concerning how the normative ideal of democracy as collective self-determination, i.e. ‘rule by the people’, might best be brought to bear in a transnational and global context. The aim in this

Eva Erman; Andreas Follesdal

2012-01-01

318

Multiple citizenship: normative ideals and institutional challenges  

Microsoft Academic Search

Institutional suggestions for how to rethink democracy in response to changing state responsibilities and capabilities have been numerous and often mutually incompatible. This suggests that conceptual unclarity still reigns concerning how the normative ideal of democracy as collective self-determination, i.e. ‘rule by the people’, might best be brought to bear in a transnational and global context. The aim in this

Eva Erman; Andreas Follesdal

2011-01-01

319

Idealized Test Cases for Dynamical Core Experiments  

E-print Network

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

Jablonowski, Christiane

320

Shape theory for nuclear ideals Richard Blute  

E-print Network

Shape theory for nuclear ideals Richard Blute University of Ottawa Department of Mathematics algebraic topology, especially abstract homotopy theory, to the categorical model theory of linear logic. Shape theory is a form of abstract homotopy theory with two crucial features. First is the idea

Blute, Richard

321

Water: The Ideal Early Learning Environment  

ERIC Educational Resources Information Center

Bathtubs and swimming pools provide the ideal learning environment for people with special needs. For young preschool children, the activities that take place through water can help them develop physical fitness, facilitate motor development, reinforce perceptual-motor ability, encourage social development, and enhance self-esteem and confidence.…

Grosse, Susan J.

2008-01-01

322

Defining an Ideal Teacher Education Program1  

Microsoft Academic Search

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

Mary M. Kennedy

1997-01-01

323

A jetlet hierarchy for ideal fluid dynamics  

E-print Network

Truncated Taylor expansions of smooth flow maps are used in Hamilton's principle to derive a multiscale Lagrangian particle representation of ideal fluid dynamics. Numerical simulations for scattering of solutions at one level of truncation are found to produce solutions at higher levels. These scattering events to higher levels in the Taylor expansion are interpreted as modeling a cascade to smaller scales.

C. J. Cotter; D. D. Holm; H. O. Jacobs; D. M. Meier

2014-02-01

324

Homological Invariants of Monomial and Binomial Ideals  

E-print Network

. It is known, due to G. Lyubeznik, that arithmetic rank of a square-free monomial ideal I is at least the projective dimension of R/I. As an application of the results in Chapter 2, we show in Chapter 4 that the multiplicity conjectures of J. Herzog, C. Huneke...

Kummini, Neelakandhan Manoj

2008-08-19

325

Quantum Shock Waves and Domain Walls in the Real-Time Dynamics of a Superfluid Unitary Fermi Gas  

SciTech Connect

We show that in the collision of two superfluid fermionic atomic clouds one observes the formation of quantum shock waves as discontinuities in the number density and collective flow velocity. Domain walls, which are topological excitations of the superfluid order parameter, are also generated and exhibit abrupt phase changes by $\\pi$ and slower motion than the shock waves. The domain walls are distinct from the gray soliton train or number density ripples formed in the wake of the shock waves and observed in the collisions of superfluid bosonic atomic clouds. Domain walls with opposite phase jumps collide elastically.

Bulgac, Aurel; Luo, Yuan-Lung; Roche, Kenneth J.

2012-04-10

326

Quantum Shock Waves and Domain Walls in the Real-Time Dynamics of a Superfluid Unitary Fermi Gas  

E-print Network

We show that in the collision of two superfluid fermionic atomic clouds one observes the formation of quantum shock waves as discontinuities in the number density and collective flow velocity. Domain walls, which are topological excitations of the superfluid order parameter, are also generated and exhibit abrupt phase changes by $\\pi$ and slower motion than the shock waves. The domain walls are distinct from the gray soliton train or number density ripples formed in the wake of the shock waves and observed in the collisions of superfluid bosonic atomic clouds. Domain walls with opposite phase jumps appear to collide elastically.

Aurel Bulgac; Yuan-Lung; Luo; Kenneth J. Roche

2011-08-08

327

Demonstrating the Gas Laws.  

ERIC Educational Resources Information Center

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.…

Holko, David A.

1982-01-01

328

Quantum Erasure: Quantum Interference Revisited  

E-print Network

Recent experiments in quantum optics have shed light on the foundations of quantum physics. Quantum erasers - modified quantum interference experiments - show that quantum entanglement is responsible for the complementarity principle.

Stephen P. Walborn; Marcelo O. Terra Cunha; Sebastião Pádua; Carlos H. Monken

2005-03-07

329

Quantum Gibbs ensemble Monte Carlo  

NASA Astrophysics Data System (ADS)

We present a path integral Monte Carlo method which is the full quantum analogue of the Gibbs ensemble Monte Carlo method of Panagiotopoulos to study the gas-liquid coexistence line of a classical fluid. Unlike previous extensions of Gibbs ensemble Monte Carlo to include quantum effects, our scheme is viable even for systems with strong quantum delocalization in the degenerate regime of temperature. This is demonstrated by an illustrative application to the gas-superfluid transition of 4He in two dimensions.

Fantoni, Riccardo; Moroni, Saverio

2014-09-01

330

The Ideal Man and Woman According to University Students  

ERIC Educational Resources Information Center

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

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

2009-01-01

331

A multiwave approximate Riemann solver for ideal MHD based on relaxation. I: theoretical framework  

Microsoft Academic Search

We present a relaxation system for ideal magnetohydrodynamics (MHD) that is an extension of the Suliciu relaxation system\\u000a for the Euler equations of gas dynamics. From it one can derive approximate Riemann solvers with three or seven waves, that\\u000a generalize the HLLC solver for gas dynamics. Under some subcharacteristic conditions, the solvers satisfy discrete entropy\\u000a inequalities, and preserve positivity of

François Bouchut; Christian Klingenberg; Knut Waagan

2007-01-01

332

Many-body dimensional perturbation theory for quantum confined systems with a focus on atomic gas Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

Systems that involve N identical, interacting particles under quantum confinement appear throughout many areas of physics, including chemical, condensed matter, and atomic physics. In this thesis, we present the methods of dimensional perturbation theory, a powerful set of tools that uses symmetry to yield simple results for studying such many-body systems. We present a detailed discussion of the dimensional continuation of the N-particle Schrodinger equation, the D ? infinity equilibrium structure, and the normal-mode oscillations of this structure. We use the Wilson FG matrix method to derive general, analytical expressions for the many-body normal-mode vibrational frequencies, and we give analytical results for three N-body quantum-confined systems: the N-electron atom, N-electron quantum dot, and N-atom inhomogeneous Bose-Einstein condensate with a repulsive hard-core potential. The focus of this thesis will be on the many-body physics of Bose-Einstein condensates (BEC). The achievement of BEC in magnetically trapped alkali-metal atoms in 1995 has generated a considerable amount of experimental and theoretical activity in recent years. In typical BEC experiments, the average distance between the bose atoms is much larger than the range of the atomic interactions, and hence, the properties of these weakly interacting condensates have been successfully described by the mean-field nonlinear Gross-Pitaevskii equation. Recently, however, no longer restricted to the atom's natural interaction parameter, experimentalists have created condensates with a "knob" (i.e., a Feshbach resonance) that allows them to adjust the interaction to whatever strength, repulsive or attractive, they wish. These strongly interacting condensates provide a new test bed for fundamental atomic and many-body physics. In this thesis we develop a theory that goes beyond the standard mean-field approximation for many-body systems. Feshbach resonances notwithstanding, most experimentally realized atomic-vapor condensates are dilute and are best described by the mean-field Gross-Pitaevskii equation. For this reason, we use dimensional scaling methods to obtain an analytical approximation to the GP equation that is more accurate and flexible than the commonly used ground-state Thomas-Fermi approximation. We also demonstrate the power of dimensional perturbation theory by providing a full solution of a model BEC Hamiltonian and a two-electron quantum dot Hamiltonian. A feature shared by these examples is the high degree of accuracy provided by the lowest orders of the perturbation theory. In our approach to the full many-body BEC Hamiltonian, we use the lowest orders of many-body dimensional perturbation theory to obtain semi-analytical ground-state energies and collective excitation frequencies. Our many-body calculations for BEC's compare well with the Gross-Pitaevskii results in the weakly-interacting regime, as they should, and are much improved over mean-field theory predictions in the strongly-interacting regime.

McKinney, Brett Allen

333

Analysis of operational filtration data part I. Ideal candle filter behavior  

Microsoft Academic Search

Operating data for the hot-gas filtration system of the Integrated Gasification and Cleanup Facility (IGCF) at the Federal Energy Technology Center are carefully analyzed. A model for candle filters is developed and used to describe the ideal filtration process. The parameters of the model are evaluated with a least-square error fit procedure. It is shown that the model predicts the

Duane H. Smith; Victor Powell; Goodarz Ahmadi; Essam Ibrahim

1997-01-01

334

Ideally glassy hydrogen-bonded networks  

NASA Astrophysics Data System (ADS)

The axiomatic theory of ideally glassy networks, which has proved effective in describing phase diagrams and properties of chalcogenide and oxide glasses and their foreign interfaces, is broadened here to include intermolecular interactions in hydrogen-bonded polyalcohols such as glycerol, monosaccharides (glucose), and the optimal bioprotective hydrogen-bonded disaccharide networks formed from trehalose. The methods of Lagrangian mechanics and Maxwellian scaffolds are useful at the molecular level when bonding hierarchies are characterized by constraint counting similar to the chemical methods used by Huckel and Pauling. Whereas Newtonian molecular dynamical methods are useful for simulating large-scale interactions for times of order 10ps , constraint counting describes network properties on glassy (almost equilibrated) time scales which may be of cosmological order for oxide glasses or years for trehalose. The ideally glassy network of trehalose may consist of extensible tandem sandwich arrays.

Phillips, J. C.

2006-01-01

335

Variations in task and the ideal observer  

SciTech Connect

In most previous studies involving the ideal observer, the task considered has been that of simple detection where it is assumed that there is complete a priori knowledge of the background and of the possible object's shape, amplitude, and position. It is shown that redefining the detection task to include the possibility of an unknown, slowly varying background reduces the importance of the low-frequency components in the image for the ideal observer. More complicated tasks than object detection are also considered, such as determination of an object's position and width and the resolution of two objects. These higher-order tasks further enhance the importance of the high-frequency information content of the image.

Hanson, K.M.

1983-01-01

336

Room-Temperature Quantum Cloning Machine with Full Coherent Phase  

E-print Network

Room-Temperature Quantum Cloning Machine with Full Coherent Phase Control in Nanodiamond Yan to the classical world, an unknown quantum state cannot be cloned ideally, as stated by the no-cloning theorem. However, it is expected that approximate or probabilistic quantum cloning will be necessary for different

Wang, Wei Hua

337

Initialization and readout of spin chains for quantum information transport  

Microsoft Academic Search

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 information transport, as they closely emulate a one-dimensional spin chain, while magnetic resonance techniques can be used to drive the spin chain dynamics and probe the

Gurneet Kaur; Paola Cappellaro

2012-01-01

338

Imaging vasculature and lymphatic flow in mice using quantum dots.  

PubMed

Quantum dots are ideal probes for fluorescent imaging of vascular and lymphatic tissues. On injection into appropriate sites, red- and near-infrared-emitting quantum dots provide excellent definition of vasculature, lymphoid organs, and lymph nodes draining both normal tissues and tumors. We detail methods for use with commercially available quantum dots and discuss common difficulties. PMID:19685300

Ballou, Byron; Ernst, Lauren A; Andreko, Susan; Fitzpatrick, James A J; Lagerholm, B Christoffer; Waggoner, Alan S; Bruchez, Marcel P

2009-01-01

339

What's an ideal energy efficiency project?  

E-print Network

What?s an ideal energy efficiency project? 1 The Supermarket Industry 2 Supermarket Industry ? The?Project ? The?Challenges ? The?Benefits 3 How it started 4 The Project ? Supermarkets?? built?to?waste ?No?natural?lighting?or?poor...?design ? Excessive?artificial?lighting ?Open?refrigerated?cabinets ?Massive?heat/cool?fighting 5 What does this cause? ?Very?large?lighting?loads ? Increased?glare ?Huge?refrigeration?loads ?Cold?customers ? Increased?space?heating ?Poor...

Dazeley, J.

2012-01-01

340

Linear ideal MHD stability calculations for ITER  

SciTech Connect

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

Hogan, J.T.

1988-01-01

341

Structure of the Star with Ideal Gases  

E-print Network

In this paper, we provide a simplified stellar structure model for ideal gases, in which the particles are only driven by gravity. According to the model, the structural information of the star can be roughly solved by the total mass and radius of a star. To get more accurate results, the model should be modified by introducing other interaction among particles and rotation of the star.

Ying-Qiu Gu

2007-12-03

342

Dust Transport in MRI Turbulent Disks: Ideal and Non-ideal MHD with Ambipolar Diffusion  

E-print Network

We study dust transport in turbulent protoplanetary disks using three-dimensional global unstratified magnetohydrodynamic (MHD) simulations including Lagrangian dust particles. The turbulence is driven by the magnetorotational instability (MRI) with either ideal or non-ideal MHD that includes ambipolar diffusion (AD). In ideal MHD simulations, the surface density evolution (except for dust that drifts fastest), turbulent diffusion, and vertical scale height of dust can all be reproduced by simple one-dimensoinal and/or analytical models. However, in AD dominated simulations which simulate protoplanetary disks beyond 10s of AU, the vertical scale height of dust is larger than previously predicted. To understand this anomaly in more detail, we carry out both unstratified and stratified local shearing box simulations with Lagrangian particles, and find that turbulence in AD dominated disks has very different properties (e.g., temporal autocorrelation functions and power spectra) than turbulence in ideal MHD disk...

Zhu, Zhaohuan; Bai, Xue-Ning

2014-01-01

343

SOM IDEAL Faculty Discussion Groups Report 1 School of Medicine IDEAL Team Project  

E-print Network

Developing Excellence in Academic Leadership (IDEAL) is a three-year program funded by the National ScienceD, Professor of Neuroscience and Associate Dean for Graduate Education, Ruth Siegel, PhD, Professor

Rollins, Andrew M.

344

Ideal Bipolar Host Materials with Bis-benzimidazole Unit for Highly Efficient Solution-Processed Green Electrophosphorescent Devices.  

PubMed

An ideal host material with high triplet energy, suitable HOMO energy level, excellent thermal and electrochemical stability, and bipolar charge carrier transport ability was synthesized. A high external quantum efficiency of 13.7% and a luminance efficiency of 48.2 cd A(-1) with low efficiency roll-off were achieved in solution-processed green electrophosphorescent devices. PMID:25260110

Jiang, Wei; Tang, Jinan; Ban, Xinxin; Sun, Yueming; Duan, Lian; Qiu, Yong

2014-10-17

345

Elastin: a representative ideal protein elastomer.  

PubMed Central

During the last half century, identification of an ideal (predominantly entropic) protein elastomer was generally thought to require that the ideal protein elastomer be a random chain network. Here, we report two new sets of data and review previous data. The first set of new data utilizes atomic force microscopy to report single-chain force-extension curves for (GVGVP)(251) and (GVGIP)(260), and provides evidence for single-chain ideal elasticity. The second class of new data provides a direct contrast between low-frequency sound absorption (0.1-10 kHz) exhibited by random-chain network elastomers and by elastin protein-based polymers. Earlier composition, dielectric relaxation (1-1000 MHz), thermoelasticity, molecular mechanics and dynamics calculations and thermodynamic and statistical mechanical analyses are presented, that combine with the new data to contrast with random-chain network rubbers and to detail the presence of regular non-random structural elements of the elastin-based systems that lose entropic elastomeric force upon thermal denaturation. The data and analyses affirm an earlier contrary argument that components of elastin, the elastic protein of the mammalian elastic fibre, and purified elastin fibre itself contain dynamic, non-random, regularly repeating structures that exhibit dominantly entropic elasticity by means of a damping of internal chain dynamics on extension. PMID:11911774

Urry, D W; Hugel, T; Seitz, M; Gaub, H E; Sheiba, L; Dea, J; Xu, J; Parker, T

2002-01-01

346

Elastin: a representative ideal protein elastomer.  

PubMed

During the last half century, identification of an ideal (predominantly entropic) protein elastomer was generally thought to require that the ideal protein elastomer be a random chain network. Here, we report two new sets of data and review previous data. The first set of new data utilizes atomic force microscopy to report single-chain force-extension curves for (GVGVP)(251) and (GVGIP)(260), and provides evidence for single-chain ideal elasticity. The second class of new data provides a direct contrast between low-frequency sound absorption (0.1-10 kHz) exhibited by random-chain network elastomers and by elastin protein-based polymers. Earlier composition, dielectric relaxation (1-1000 MHz), thermoelasticity, molecular mechanics and dynamics calculations and thermodynamic and statistical mechanical analyses are presented, that combine with the new data to contrast with random-chain network rubbers and to detail the presence of regular non-random structural elements of the elastin-based systems that lose entropic elastomeric force upon thermal denaturation. The data and analyses affirm an earlier contrary argument that components of elastin, the elastic protein of the mammalian elastic fibre, and purified elastin fibre itself contain dynamic, non-random, regularly repeating structures that exhibit dominantly entropic elasticity by means of a damping of internal chain dynamics on extension. PMID:11911774

Urry, D W; Hugel, T; Seitz, M; Gaub, H E; Sheiba, L; Dea, J; Xu, J; Parker, T

2002-02-28

347

Chemical potential of the low-dimensional multisubband Fermi gas.  

PubMed

In this paper, the chemical potential of two-dimensional (2D) and quasi-one-dimensional (Q1D) multisubband charged Fermi gases is evaluated. We start with a rather general formula for the thermodynamic potential of an ideal quantum statistical system with arbitrary occupation-number to calculate, as a particular case, the chemical potential of the multisubband 2D Fermi gas described by a quadratic energy spectrum. The chemical potential is also studied in the case of a low-dimensional Fermi gas in the presence of a quantizing magnetic field. The same approach is used to study the chemical potential of a multisubband Q1D Fermi gas. The influence of temperature is considered. We found interesting analytical results for special limits as well as numerical results that may be important for the description of both the thermodynamic and kinetic properties of Fermi systems in low dimensionality. PMID:21403365

Sokolova, Elena S; Sokolov, Sviatoslav S; Studart, Nelson

2010-11-24

348

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

Microsoft Academic Search

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

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

2012-01-01

349

Quantum master equation for collisional dynamics of massive particles with internal degrees of freedom  

NASA Astrophysics Data System (ADS)

We address the microscopic derivation of a quantum master equation in Lindblad form for the dynamics of a massive test particle with internal degrees of freedom, interacting through collisions with a background ideal gas. When either internal or center-of-mass degrees of freedom can be treated classically, previously established equations are obtained as special cases. If in an interferometric setup the internal degrees of freedom are not detected at the output, the equation can be recast in the form of a generalized Lindblad structure, which describes non-Markovian effects. The effect of internal degrees of freedom on center-of-mass decoherence is considered in this framework.

Smirne, Andrea; Vacchini, Bassano

2010-10-01

350

Increased body satisfaction after exposure to thin ideal children's television in young girls showing thin ideal internalisation.  

PubMed

This study tested the direct effect of watching thin ideal children's television on body satisfaction in preadolescent girls (6-8 years old). A within-subject design was used in which girls (N?=?51) were tested three times. They watched television clips in random order containing either (1) thin ideal animated characters or (2) animated characters with no thin ideal features or (3) 'real' human actors with no thin ideal features. After watching, their state body satisfaction was measured. Girls with higher levels of thin ideal internalisation showed higher body satisfaction after exposure to the thin ideal characters than after exposure to animated or real characters featuring no thin ideal features. No differences on body satisfaction between the exposure conditions were found in girls with lower levels of thin ideal internalisation. The results might suggest that young girls who internalised the thin ideal are inspired by thin ideal characters in children's media. PMID:22512700

Anschutz, Doeschka J; Engels, Rutger C M E; Van Strien, Tatjana

2012-01-01

351

Spinning gas clouds - without vorticity  

Microsoft Academic Search

Ovsiannikov and Dyson have considered an ordinary differential reduction of the gas-dynamical equations for an ideal gas which is adiabatically expanding and rotating. Gaffet has shown, based on its Painlevé property, the complete integrability of that ellipsoidal gas cloud model, when there is neither rotation nor vorticity and the gas is monatomic (gamma = 5\\/3), and has conjectured that the

B. Gaffet

2000-01-01

352

Trace gas sensing using quantum cascade lasers and a fiber-coupled optoacoustic sensor: Application to formaldehyde  

NASA Astrophysics Data System (ADS)

We will report here on the design and realization of an optoacoustic sensor for the detection of formaldehyde. The sensor consists of a commercial QCL and a resonant PA cell. Two different cell configurations have been investigated: a "standard" H cell and an innovative T-cell with an optical fiber directly inserted into. Two different type of sound detector have been employed: electret microphones and optical MEMS-based microphone. As possible applications, we will describe the results obtained in the detection of formaldehyde (CH2O), a gas of great interest for industrial processes and environmental monitoring.

Elia, A.; Spagnolo, V.; Di Franco, C.; Lugarà, P. M.; Scamarcio, G.

2010-03-01

353

Interaction with thermal radiation in the free expansion and mixing of ideal gases and Gibbs' paradox in classical thermodynamics  

E-print Network

The standard theory of ideal gases ignores the interaction of the gas particles with the thermal radiation (photon gas) that fills the otherwise vacuum space between them. This is an unphysical feature of the theory since every material in this universe, and hence also the particles of a gas, absorbs and radiates thermal energy. The interaction with the thermal radiation that is contained within the volume of the body may be important in gases since the latter, unlike solids and liquids, are capable of undergoing conspicuous volume changes. Taking this interaction into account makes the behaviour of the ideal gases more realistic and removes Gibbs' paradox.

A. Paglietti

2009-04-26

354

Statistical Theory of the Ideal MHD Geodynamo  

NASA Technical Reports Server (NTRS)

A statistical theory of geodynamo action is developed, using a mathematical model of the geodynamo as a rotating outer core containing an ideal (i.e., no dissipation), incompressible, turbulent, convecting magnetofluid. On the concentric inner and outer spherical bounding surfaces the normal components of the velocity, magnetic field, vorticity and electric current are zero, as is the temperature fluctuation. This allows the use of a set of Galerkin expansion functions that are common to both velocity and magnetic field, as well as vorticity, current and the temperature fluctuation. The resulting dynamical system, based on the Boussinesq form of the magnetohydrodynamic (MHD) equations, represents MHD turbulence in a spherical domain. These basic equations (minus the temperature equation) and boundary conditions have been used previously in numerical simulations of forced, decaying MHD turbulence inside a sphere [1,2]. Here, the ideal case is studied through statistical analysis and leads to a prediction that an ideal coherent structure will be found in the form of a large-scale quasistationary magnetic field that results from broken ergodicity, an effect that has been previously studied both analytically and numerically for homogeneous MHD turbulence [3,4]. The axial dipole component becomes prominent when there is a relatively large magnetic helicity (proportional to the global correlation of magnetic vector potential and magnetic field) and a stationary, nonzero cross helicity (proportional to the global correlation of velocity and magnetic field). The expected angle of the dipole moment vector with respect to the rotation axis is found to decrease to a minimum as the average cross helicity increases for a fixed value of magnetic helicity and then to increase again when average cross helicity approaches its maximum possible value. Only a relatively small value of cross helicity is needed to produce a dipole moment vector that is aligned at approx.10deg with the rotation axis.

Shebalin, J. V.

2012-01-01

355

The ideal science student and problem solving  

NASA Astrophysics Data System (ADS)

The purpose of this dissertation was to examine the relationship between students' social mental models of the ideal science student, science epistemological beliefs, problem solving strategies used, and problem solving ability in a robotics environment. Participants were twenty-six academically advanced eleven and twelve year old students attending the Center for Talented Youth summer camp. Survey data was collected from the students including demographic background, views of the ideal science student, and science epistemological beliefs. Students also solved a robotics challenge. This problem solving session was videotaped and students were asked to think aloud as they solved the problem. Two social mental models were identified, a traits-based social mental model and a robust social mental model. A significant association was found between social mental model group and strategy usage. The robust social mental model group is more likely to use domain specific strategies than the traits-based group. Additionally, the robust social mental model group achieved significantly higher scores on their final solution than the traits-based social mental model group. Science epistemological beliefs do not appear to be associated with students' social mental model of the ideal science student. While students with a puzzle-solver view of science were more likely to use domain specific strategies in the planning phase of the problem solving session, there was no significant difference in problem solving ability between this group and students who have a dynamic view of the nature of science knowledge. This difference in strategy usage and problem solving performance may be due to a difference in the students' views of learning and cognition. The robust social mental model group evidenced a situative view of learning and cognition. These students made excellent use of the tools available in the task environment. The traits-based social mental model group displayed an information processing view of learning and cognition. These students were more likely to attempt to solve the problem based only on their mental representations of the problems.

Sullivan, Florence R.

356

"The Scientific Method" as Myth and Ideal  

NASA Astrophysics Data System (ADS)

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

Woodcock, Brian A.

2014-10-01

357

Ideal Magnetohydrodynamic Stability of the NCSX  

SciTech Connect

The ideal magnetohydrodynamic (MHD) stability of the National Compact Stellarator Experiment (NCSX) is extensively analyzed using the most advanced three-dimensional MHD codes. It is shown that the NCSX is stable to finite-n MHD modes, including the vertical mode, external kink modes and ballooning modes. However, high-n external kink modes that peak near the plasma edge are found to be weakly unstable. A global calculation shows that finite-n ballooning modes are significantly more stable than the local infinite-n modes.

Fu, GuoYong [Princeton Plasma Physics Laboratory (PPPL); Isaev, Maxim Yu [Kurchatov Institute, Moscow, Russia; Ku, Long-Poe [Princeton Plasma Physics Laboratory (PPPL); Mikhailov, M [Kurchatov Institute, Moscow, Russia; Redi, M H [Princeton Plasma Physics Laboratory (PPPL); Sanchez, Raul [ORNL; Subbotin, A [Kurchatov Institute, Moscow, Russia; Hirshman, Steven Paul [ORNL; Cooper, W Anthony [CRPP/EPFL, Association Euratom-Suisse, Lausanne, Switzerland; Monticello, D. [Princeton Plasma Physics Laboratory (PPPL); Reiman, A H [Princeton Plasma Physics Laboratory (PPPL); Zarnstorff, M. C. [Princeton Plasma Physics Laboratory (PPPL)

2007-01-01

358

Dark energy from cosmological fluids obeying a Shan-Chen non-ideal equation of state  

E-print Network

We consider a Friedmann-Robertson-Walker universe with a fluid source obeying a non-ideal equation of state with "asymptotic freedom," namely ideal gas behavior (pressure changes directly proportional to density changes) both at low and high density regimes, following a fluid dynamical model due to Shan and Chen. It is shown that, starting from an ordinary energy density component, such fluids naturally evolve towards a universe with a substantial "dark energy" component at the present time, with no need of invoking any cosmological constant. Moreover, we introduce a quantitative indicator of darkness abundance, which provides a consistent picture of the actual matter-energy content of the universe.

Bini, Donato; Gregoris, Daniele; Succi, Sauro

2014-01-01

359

On probing ions at the gas-liquid interface by quantum state-resolved molecular beam scattering: the curious incident of the cation in the night time.  

PubMed

There has been a long standing controversy over the preferential presence or absence of cations vs. anions at the gas-liquid interface, dating back to early theoretical efforts by Onsager and co-workers [J. Chem. Phys., 1934, 2, 528]. In the present work, we describe our first efforts to selectively probe ions at the interface via a completely novel approach, based on scattering high energy, jet cooled molecular projectiles from the surface of hydrogen bonded liquids with dissolved alkali halide salts as the source of solvated charges. In particular, this work focuses on preliminary results from quantum state- resolved scattering studies as a function of anion (Cl-, I-), and cation identity (Li+, Na+, K+) in alkali halide/glycerol solutions. By way of physical picture, a quadrupolar projectile such as CO2 preferentially aligns parallel (anions) or perpendicular (cations) to the interface, which could therefore make rotational energy transfer sensitive to the sign of the ion charge. Experimentally, we find that the impulsive scattered (IS) CO2 rotational distributions reveal a clear dependence on anion identity (e.g., hotter for [I-] than [Cl-]), but with essentially no corresponding sensitivity to cation species (e.g., [Li+] indistinguishable from [K+]). Detailed trajectory calculations are used to provide additional insight into the anticipated and observed experimental trends. PMID:23230774

Gisler, Andrew W; Nesbitt, David J

2012-01-01

360

Effect of the surface on the electronic properties of a two-dimensional electron gas as measured by the quantum Hall effect  

NASA Astrophysics Data System (ADS)

The effect of the surface treatments on the transport properties of a two-dimensional electron gas was studied at the quantum limit. The surface of the Al0.36Ga0.64As/GaAs heterostructure was either coated with gold or etched with HCl solution, or etched and then coated by a self-assembled monolayer (SAM) of either phosphonated (ODP-C18H39PO3) or thiolated (ODT-C18H37S) molecules. The etching process was found to reduce significantly both the mobility and the charge density. This effect was reversed upon sequential adsorption of the phosphonated SAM. We propose fine tuning of the device performance by the flexible chemistry of the assembled molecules, two of them demonstrated here. The results indicate that the surface oxidation does not necessarily play the dominant role in this respect and, in particular, that octadecane phosphonic acid (ODP) can protect the substrate from both oxidation and the formation of a passivating carbon layer. In contrast, octadecanethiol (ODT) is not stable enough and is not effective in eliminating surface states, as a result devices covered with ODT behave like those with etched surfaces.

Kopnov, G.; Umansky, V. Y.; Cohen, H.; Shahar, D.; Naaman, R.

2010-01-01

361

Quantum fluid dynamics approach for electronic structure calculation: application to the study of ground-state properties of rare gas atoms  

NASA Astrophysics Data System (ADS)

We explore the usefulness of a quantum fluid dynamics (QFD) approach for quantitative electronic structure calculations of many-electron systems. By combining QFD and density functional theory, a single time-dependent nonlinear QFD equation can be derived. The equation is further transformed into a diffusion-type form by an imaginary-time evolution method, whose asymptotic solution reaches a global minimum and the many-body ground-state wavefunction. The time-dependent generalized pseudospectral method is extended to solve the diffusion equation in spherical coordinates, allowing optimal and nonuniform spatial discretization and accurate and efficient solution of the diffusion function in space and time. The procedure is applied to the study of electronic energies, densities and other ground-state properties of noble gas atoms (He, Ne, Ar, Kr, Xe). The results are in good agreement with other best available values. The method offers a conceptually appealing and computationally practical procedure for the treatment of many-electron systems beyond the Hartree-Fock level.

Roy, Amlan K.; Chu, Shih-I.

2002-05-01

362

Quantum Cryptography and Quantum Computation  

E-print Network

Quantum Cryptography and Quantum Computation Network Security Course Project Report by Hidayath.2 Bases of the Hilbert space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 Quantum principle . . . . . . . . . . . . . . . . . . . . . . 5 3 Quantum Cryptography 6 3.1 The BB84 protocol

North Carolina at Chapel Hill, University of

363

Quantum Optics, Quantum Nanophysics, Quantum Information  

NSDL National Science Digital Library

This site contains the research news and project descriptions of the work in quantum physics by the research group of Prof. Anton Zeilinger. This includes quantum methods of teleportation and cryptography, quantum information, and entangled states.

Zeilinger, Anton

2003-10-10

364

Transforming quantum operations: quantum supermaps  

E-print Network

We introduce the concept of quantum supermap, describing the most general transformation that maps an input quantum operation into an output quantum operation. Since quantum operations include as special cases quantum states, effects, and measurements, quantum supermaps describe all possible transformations between elementary quantum objects (quantum systems as well as quantum devices). After giving the axiomatic definition of supermap, we prove a realization theorem, which shows that any supermap can be physically implemented as a simple quantum circuit. Applications to quantum programming, cloning, discrimination, estimation, information-disturbance trade-off, and tomography of channels are outlined.

G. Chiribella; G. M. D'Ariano; P. Perinotti

2008-04-01

365

Nonlinear stability of ideal fluid equilibria  

SciTech Connect

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

Holm, D.D.

1988-01-01

366

Simple Waves in Ideal Radiation Hydrodynamics  

SciTech Connect

In the dynamic diffusion limit of radiation hydrodynamics, advection dominates diffusion; the latter primarily affects small scales and has negligible impact on the large scale flow. The radiation can thus be accurately regarded as an ideal fluid, i.e., radiative diffusion can be neglected along with other forms of dissipation. This viewpoint is applied here to an analysis of simple waves in an ideal radiating fluid. It is shown that much of the hydrodynamic analysis carries over by simply replacing the material sound speed, pressure and index with the values appropriate for a radiating fluid. A complete analysis is performed for a centered rarefaction wave, and expressions are provided for the Riemann invariants and characteristic curves of the one-dimensional system of equations. The analytical solution is checked for consistency against a finite difference numerical integration, and the validity of neglecting the diffusion operator is demonstrated. An interesting physical result is that for a material component with a large number of internal degrees of freedom and an internal energy greater than that of the radiation, the sound speed increases as the fluid is rarefied. These solutions are an excellent test for radiation hydrodynamic codes operating in the dynamic diffusion regime. The general approach may be useful in the development of Godunov numerical schemes for radiation hydrodynamics.

Johnson, B M

2008-09-03

367

The Statistical Mechanics of Ideal Homogeneous Turbulence  

NASA Technical Reports Server (NTRS)

Plasmas, such as those found in the space environment or in plasma confinement devices, are often modeled as electrically conducting fluids. When fluids and plasmas are energetically stirred, regions of highly nonlinear, chaotic behavior known as turbulence arise. Understanding the fundamental nature of turbulence is a long-standing theoretical challenge. The present work describes a statistical theory concerning a certain class of nonlinear, finite dimensional, dynamical models of turbulence. These models arise when the partial differential equations describing incompressible, ideal (i.e., nondissipative) homogeneous fluid and magnetofluid (i.e., plasma) turbulence are Fourier transformed into a very large set of ordinary differential equations. These equations define a divergenceless flow in a high-dimensional phase space, which allows for the existence of a Liouville theorem, guaranteeing a distribution function based on constants of the motion (integral invariants). The novelty of these particular dynamical systems is that there are integral invariants other than the energy, and that some of these invariants behave like pseudoscalars under two of the discrete symmetry transformations of physics, parity, and charge conjugation. In this work the 'rugged invariants' of ideal homogeneous turbulence are shown to be the only significant scalar and pseudoscalar invariants. The discovery that pseudoscalar invariants cause symmetries of the original equations to be dynamically broken and induce a nonergodic structure on the associated phase space is the primary result presented here. Applicability of this result to dissipative turbulence is also discussed.

Shebalin, John V.

2002-01-01

368

Ideal Polymers near Scale-Free Surfaces  

E-print Network

The number of allowed configurations of a polymer is reduced by the presence of a repulsive surface resulting in an entropic force between them. We develop a method to calculate the entropic force, and detailed pressure distribution, for long ideal polymers near a scale-free repulsive surface. For infinite polymers the monomer density is related to the electrostatic potential near a conducting surface of a charge placed at the point where the polymer end is held. Pressure of the polymer on the surface is then related to the charge density distribution in the electrostatic problem. We derive explicit expressions for pressure distributions and monomer densities for ideal polymers near a two- or three-dimensional wedge, and for a circular cone in three dimensions. Pressure of the polymer diverges near sharp corners in a manner resembling (but not identical to) the electric field divergence near conducting surfaces. We provide formalism for calculation of all components of the total force in situations without axial symmetry.

Yosi Hammer; Yacov Kantor

2013-11-17

369

Ideal polymers near scale-free surfaces  

NASA Astrophysics Data System (ADS)

The number of allowed configurations of a polymer is reduced by the presence of a repulsive surface resulting in an entropic force between them. We develop a method to calculate the entropic force, and detailed pressure distribution, for long ideal polymers near a scale-free repulsive surface. For infinite polymers the monomer density is related to the electrostatic potential near a conducting surface of a charge placed at the point where the polymer end is held. Pressure of the polymer on the surface is then related to the charge density distribution in the electrostatic problem. We derive explicit expressions for pressure distributions and monomer densities for ideal polymers near a two- or three-dimensional wedge, and for a circular cone in three dimensions. Pressure of the polymer diverges near sharp corners in a manner resembling (but not identical to) the electric field divergence near conducting surfaces. We provide formalism for calculation of all components of the total force in situations without axial symmetry.

Hammer, Yosi; Kantor, Yacov

2014-02-01

370

Global invariants in ideal magnetohydrodynamic turbulence  

SciTech Connect

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

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

2013-10-15

371

An ideal sealed source life-cycle  

SciTech Connect

In the last 40 years, barriers to compliant and timely disposition of radioactive sealed sources have become apparent. The story starts with the explosive growth of nuclear gauging technologies in the 1960s. Dozens of companies in the US manufactured sources and many more created nuclear solutions to industrial gauging problems. Today they do not yet know how many Cat 1, 2, or 3 sources there are in the US. There are, at minimum, tens of thousands of sources, perhaps hundreds of thousands of sources. Affordable transportation solutions to consolidate all of these sources and disposition pathways for these sources do not exist. The root problem seems to be a lack of necessary regulatory framework that has allowed all of these problems to accumulate with no national plan for solving the problem. In the 1960s, Pu-238 displaced Pu-239 for most neutron and alpha source applications. In the 1970s, the availability of inexpensive Am-241 resulted in a proliferation of low energy gamma sources used in nuclear gauging, well logging, pacemakers, and X-ray fluorescence applications for example. In the 1980s, rapid expansion of worldwide petroleum exploration resulted in the expansion of Am-241 sources into international locations. Improvements of technology and regulation resulted in a change in isotopic distribution as Am-241 made Pu-239 and Pu-238 obsolete. Many early nuclear gauge technologies have been made obsolete as they were replaced by non-nuclear technoogies. With uncertainties in source end of life disposition and increased requirements for sealed source security, nuclear gauging technology is the last choice for modern process engineering gauging solutions. Over the same period, much was learned about licensing LLW disposition facilities as evident by the closure of early disposition facilities like Maxey Flats. The current difficulties in sealed source disposition start with adoption of the NLLW policy act of 1985, which created the state LLW compact system they we have today. This regulation created a new regulatory framework seen as promising at the time. However, now they recognize that, despite the good intentions, the NIJWP/85 has not solved any source disposition problems. The answer to these sealed source disposition problems is to adopt a philosophy to correct these regulatory issues, determine an interim solution, execute that solution until there is a minimal backlog of sources to deal with, and then let the mechanisms they have created solve this problem into the foreseeable future. The primary philosophical tenet of the ideal sealed source life cycle follows. You do not allow the creation (or importation) of any source whose use cannot be justified, which cannot be affordably shipped, or that does not have a well-delinated and affordable disposition pathway. The path forward dictates that we fix the problem by embracing the Ideal Source Life cycle. In figure 1, we can see some of the elements of the ideal source life cycle. The life cycle is broken down into four portions, manufacture, use, consolidation, and disposition. These four arbitrary elements allow them to focus on the ideal life cycle phases that every source should go through between manufacture and final disposition. As we examine the various phases of the sealed source life cycle, they pick specific examples and explore the adoption of the ideal life cycle model.

Tompkins, Joseph Andrew [Los Alamos National Laboratory

2009-01-01

372

Ideal Amenability of Second Duals of Banach Algebras  

Microsoft Academic Search

In this paper we study the ideal amenability of second duals of Ba- nach algebras. We investigate relations between ideal amenability of the second dual of a Banach algebra with the first and the second Arens products.

M. Eshaghi Gordji; F. Habibian; B. Hayati

2007-01-01

373

Stratospheric radiation, dynamics and trace gases in an idealized GCM  

NASA Astrophysics Data System (ADS)

Stratospheric radiation, dynamics, and trace gas distributions form a complex, coupled system. It is therefore difficult to establish direct cause-and-effect relationships between different variables, in both observations and comprehensive numerical models. We employ an idealized model to disentangle effects of radiation, dynamics and tracer transport. Besides the advantages in terms of hardware requirement, such models can advance understanding by testing basic theories and processes. We seek to determine the limits of such simple frameworks, outside which more complex models are needed to investigate the underlying mechanisms. Here, we will concentrate on the effect of dynamics through transport and temperature on water vapor and ozone, and the feedback of these tracers on dynamics via radiation. While water vapor response on dynamics is weak, the impact of dynamics on it is strong. Specifically, the see-saw of tropical and polar vortex temperatures, driven by insolation and dynamics, constrains water vapor in the stratosphere. Conversely, ozone acts strongly on dynamics, and we discuss important aspects of this feedback beyond the ozone hole. As a potent greenhouse gas and chemical agent, understanding the variation in water vapor distribution under changing dynamics is essential for future trend estimations. The radiative effect of ozone, on the other hand, has mainly received attention in the context of the ozone hole, cooling and strengthening the polar vortex, but it can also play its part in the seasonal cycle of tropical temperatures.

Jucker, M.; Fueglistaler, S.; Vallis, G. K.

2012-12-01

374

On Power Idealization Filter Topologies of Lattice Implication Algebras  

PubMed Central

The aim of this paper is to introduce power idealization filter topologies with respect to filter topologies and power ideals of lattice implication algebras, and to investigate some properties of power idealization filter topological spaces and their quotient spaces. PMID:25258735

Bai, Shi-Zhong

2014-01-01

375

Micro-chaos and idealization in cartesian physics  

Microsoft Academic Search

The philosophical study of idealization in science often begins with case studies drawn from classical mechanics, and with good reason. Newton himself was able to deploy various idealizations with so much success that they still serve as models. The approach in this essay is different. I shall examine a notorious case of unsuccessful scientific idealizations - the ones employed by

Alan Nelson

1995-01-01

376

Quantitative control of idealized analysis models of thin , Junzhe Zhenga  

E-print Network

Quantitative control of idealized analysis models of thin designs Ming Li1a , Junzhe Zhenga , Ralph analysis, model idealization is often used, where defeaturing, and/or local dimension reduction of thin. During this process, an initial step of model idealization [1, 2] is often performed to convert the fully

Martin, Ralph R.

377

Derivations into duals of closed ideals of Banach algebras  

Microsoft Academic Search

Let $\\\\cal A$ be a Banach algebra. We study those closed ideals $I$ of $\\\\cal A$ for which the first cohomology group of $\\\\cal A$ with coefficients in $I^*$ is trivial; i.e. $H^1(\\\\cal A,I^*)=\\\\{0\\\\}$. We investigate such closed ideals when $\\\\cal A$ is weakly amenable or biflat. Also we give some hereditary properties of ideal amenability.

M. Eshaghi Gordji; B. Hayati; S. A. R. Hosseiniun

2006-01-01

378

Black and White Adolescent Females Perceptions of Ideal Body Size.  

ERIC Educational Resources Information Center

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

Parnell, Kathy; And Others

1996-01-01

379

Raman Quantum Memory of Photonic Polarised Entanglement  

E-print Network

Quantum entanglement of particles is regarded as a fundamental character in quantum information, in which quantum state should be given for whole system instead of independently describing single particle. Constructing quantum memory of photonic entanglement is essential for realizing quantum networks, which had been performed previously by many memory protocols. Of which Raman quantum memory gives advantages in broadband and high speed properties, and many people have been attracted in this field. However, Raman quantum memory of photonic polarised entanglement is a challenge work and still missing. Here, we report two Raman quantum memories based on gas atomic ensembles: 1, Heralded Raman quantum memory of hybrid entanglement of path and polarization of single photon. 2, Raman storage of two particle photonic polarised entangled state. Our experimental performances of these two different Raman quantum storages of photonic entanglement show a very promising prospective in quantum information science.

Dong-Sheng Ding; Wei Zhang; Zhi-Yuan Zhou; Shuai Shi; Bao-Sen Shi; Guang-Can Guo

2014-10-27

380

Quantum Tetrahedra  

E-print Network

We discuss in details the role of Wigner 6j symbol as the basic building block unifying such different fields as state sum models for quantum geometry, topological quantum field theory, statistical lattice models and quantum computing. The apparent twofold nature of the 6j symbol displayed in quantum field theory and quantum computing -a quantum tetrahedron and a computational gate- is shown to merge together in a unified quantum-computational SU(2)-state sum framework.

Mauro Carfora; Annalisa Marzuoli; Mario Rasetti

2010-01-25

381

Thermal stability of idealized folded carbyne loops  

PubMed Central

Self-unfolding items provide a practical convenience, wherein ring-like frames are contorted into a state of equilibrium and subsequently ?pop up’ or deploy when perturbed from a folded structure. Can the same process be exploited at the molecular scale? At the limiting scale is a closed chain of single atoms, used here to investigate the limits of stability of such folded ring structures via full atomistic molecular dynamics. Carbyne is a one-dimensional carbon allotrope composed of sp-hybridized carbon atoms. Here, we explore the stability of idealized carbyne loops as a function of chain length, curvature, and temperature, and delineate an effective phase diagram between folded and unfolded states. We find that while overall curvature is reduced, in addition to torsional and self-adhesive energy barriers, a local increase in curvature results in the largest impedance to unfolding. PMID:24252156

2013-01-01

382

Review of Idealized Aircraft Wake Vortex Models  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

383

Infinitary Species: an idealized mathematical species concept  

E-print Network

In their paper [5], Dress, Moulton, Steel, and Wu introduced a directed graph that describes the ancestral relations between all organisms that have ever lived. We extend that graph to also include all organisms that ever will live and operate under the assumption it is infinite. This assumption admits certain clusters of organisms which have some ideal properties of genera and species (that is, in the Species Concepts sense, not the Species Delimitation sense, as de Queiroz [12] distinguishes them). In a certain sense, the infinitary species we introduce are unavoidable because they are the natural resolution to species sorites paradoxes. Along with infinitary genera, infinitary species have remarkably rich mathematical properties and a primary goal of the paper is to submit these as a novel infinitary response to Sturmfels' [14] question, "Can biology lead to new theorems"?

Alexander, Samuel

2012-01-01

384

The Allee-type ideal free distribution.  

PubMed

The ideal free distribution (IFD) in a two-patch environment where individual fitness is positively density dependent at low population densities is studied. The IFD is defined as an evolutionarily stable strategy of the habitat selection game. It is shown that for low and high population densities only one IFD exists, but for intermediate population densities there are up to three IFDs. Population and distributional dynamics described by the replicator dynamics are studied. It is shown that distributional stability (i.e., IFD) does not imply local stability of a population equilibrium. Thus distributional stability is not sufficient for population stability. Results of this article demonstrate that the Allee effect can strongly influence not only population dynamics, but also population distribution in space. PMID:24306202

K?ivan, Vlastimil

2014-12-01

385

Ideal magnetohydrodynamic stability of the spheromak configuration  

SciTech Connect

Results are presented of a parametric study of the ideal magnetohydrodynamic stability properties of the spheromak, or compact torus, configuration. In the absence of a nearby conducting wall, the spheromak is always unstable to at least one current driven mode. With a conducting wall at the surface, the spheromak can be unstable to current driven modes if the current is too peaked, i.e., q/sub o/(R/a) less than or equal to 2/3, or if the shear is too low at the origin. The Mercier criterion sets an upper limit on the pressure gradient everywhere, but configurations that are everywhere Mercier stable can be unstable to pressure driven low-n modes. Stable toroidal configurations exist with a spherical wall separated by half a minor radius, and with ..beta../sub theta/ = 30%.

Jardin, S.C.

1982-01-19

386

Thermal stability of idealized folded carbyne loops  

NASA Astrophysics Data System (ADS)

Self-unfolding items provide a practical convenience, wherein ring-like frames are contorted into a state of equilibrium and subsequently pop up' or deploy when perturbed from a folded structure. Can the same process be exploited at the molecular scale? At the limiting scale is a closed chain of single atoms, used here to investigate the limits of stability of such folded ring structures via full atomistic molecular dynamics. Carbyne is a one-dimensional carbon allotrope composed of sp-hybridized carbon atoms. Here, we explore the stability of idealized carbyne loops as a function of chain length, curvature, and temperature, and delineate an effective phase diagram between folded and unfolded states. We find that while overall curvature is reduced, in addition to torsional and self-adhesive energy barriers, a local increase in curvature results in the largest impedance to unfolding.

Cranford, Steven W.

2013-11-01

387

Broken Ergodicity in Ideal, Homogeneous, Incompressible Turbulence  

NASA Technical Reports Server (NTRS)

We discuss the statistical mechanics of numerical models of ideal homogeneous, incompressible turbulence and their relevance for dissipative fluids and magnetofluids. These numerical models are based on Fourier series and the relevant statistical theory predicts that Fourier coefficients of fluid velocity and magnetic fields (if present) are zero-mean random variables. However, numerical simulations clearly show that certain coefficients have a non-zero mean value that can be very large compared to the associated standard deviation. We explain this phenomena in terms of broken ergodicity', which is defined to occur when dynamical behavior does not match ensemble predictions on very long time-scales. We review the theoretical basis of broken ergodicity, apply it to 2-D and 3-D fluid and magnetohydrodynamic simulations of homogeneous turbulence, and show new results from simulations using GPU (graphical processing unit) computers.

Morin, Lee; Shebalin, John; Fu, Terry; Nguyen, Phu; Shum, Victor

2010-01-01

388

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

NASA Technical Reports Server (NTRS)

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

Yee, H. C.; Sjogreen, B.

2004-01-01

389

Medical and Nursing Students: Concepts of Self and Ideal Self, Typical and Ideal Work Partner  

ERIC Educational Resources Information Center

Dominance and sociability scores on the Interpersonal Check List were obtained for medical and nursing students. Results indicate a discrepancy between concepts of self and ideal self, as well as considerable disagreement between medical and nursing students about their roles on the physician-nurse team. (EVH)

Rein, Ingrid

1977-01-01

390

Nonlinear electrophoresis of ideally polarizable particles  

NASA Astrophysics Data System (ADS)

We focus in this paper on the nonlinear electrophoresis of ideally polarizable particles. At high applied voltages, significant ionic exchange occurs between the electric double layer, which surrounds the particle, and the bulk solution. In addition, steric effects due to the finite size of ions drastically modify the electric potential distribution in the electric double layer. In this situation, the velocity field, the electric potential, and the ionic concentration in the immediate vicinity of the particle are described by a complicated set of coupled nonlinear partial differential equations. In the general case, these equations must be solved numerically. In this study, we rely on a numerical approach to determine the electric potential, the ionic concentration, and the velocity field in the bulk solution surrounding the particle. The numerical simulations rely on a pseudo-spectral method which was used successfully by Chu and Bazant [J. Colloid Interface Sci. 315(1), 319-329 (2007)] to determine the electric potential and the ionic concentration around an ideally polarizable metallic sphere. Our numerical simulations also incorporate the steric model developed by Kilic et al. [Phys. Rev. E 75, 021502 (2007)] to account for crowding effects in the electric double layer, advective transport, and for the presence of a body force in the bulk electrolyte. The simulations demonstrate that surface conduction significantly decreases the electrophoretic mobility of polarizable particles at high zeta potential and at high applied electric field. Advective transport in the electric double layer and in the bulk solution is also shown to significantly impact surface conduction.

Figliuzzi, B.; Chan, W. H. R.; Moran, J. L.; Buie, C. R.

2014-10-01

391

Interacting Ions in Biophysics: Real is not Ideal  

NASA Astrophysics Data System (ADS)

Ions in water are important in biology, from molecules to organs. Classically, ions in water are treated as ideal noninteracting particles in a perfect gas. Excess free energy of ion was zero. Mathematics was not available to deal consistently with flows, or interactions with ions or boundaries. Non-classical approaches are needed because ions in biological conditions flow and interact. The concentration gradient of one ion can drive the flow of another, even in a bulk solution. A variational multiscale approach is needed to deal with interactions and flow. The recently developed energetic variational approach to dissipative systems allows mathematically consistent treatment of bio-ions Na, K, Ca and Cl as they interact and flow. Interactions produce large excess free energy that dominate the properties of the high concentration of ions in and near protein active sites, channels, and nucleic acids: the number density of ions is often more than 10 M. Ions in such crowded quarters interact strongly with each other as well as with the surrounding protein. Non-ideal behavior has classically been ascribed to allosteric interactions mediated by protein conformation changes. Ion-ion interactions present in crowded solutions--independent of conformation changes of proteins--are likely to change interpretations of allosteric phenomena. Computation of all atoms is a popular alternative to the multiscale approach. Such computations involve formidable challenges. Biological systems exist on very different scales from atomic motion. Biological systems exist in ionic mixtures (extracellular/intracellular solutions), and usually involve flow and trace concentrations of messenger ions (e.g., 10-7 M Ca2+). Energetic variational methods can deal with these characteristic properties of biological systems while we await the maturation and calibration of all atom simulations of ionic mixtures and divalents.

Eisenberg, Bob

2013-05-01

392

Quantum correlation via quantum coherence  

E-print Network

Quantum correlation includes quantum entanglement and quantum discord. Both entanglement and discord have a common necessary condition--------quantum coherence or quantum superposition. In this paper, we attempt to give an alternative understanding of how quantum correlation is related to quantum coherence. We divide the coherence of a quantum state into several classes and find the complete coincidence between geometric (symmetric and asymmetric) quantum discords and some particular classes of quantum coherence. We propose a revised measure for total coherence and find that this measure can lead to a symmetric version of geometric quantum correlation which is analytic for two qubits. In particular, this measure can also arrive at a monogamy equality on the distribution of quantum coherence. Finally, we also quantify a remaining type of quantum coherence and find that for two qubits it is directly connected with quantum nonlocality.

Chang-shui Yu; Yang Zhang; Haiqing Zhao

2014-02-19

393

Einstein's idealism and a new kind of space research  

NASA Astrophysics Data System (ADS)

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

Popov, M. A.

394

Quantum walks, quantum gates, and quantum computers  

SciTech Connect

The physics of quantum walks on graphs is formulated in Hamiltonian language, both for simple quantum walks and for composite walks, where extra discrete degrees of freedom live at each node of the graph. It is shown how to map between quantum walk Hamiltonians and Hamiltonians for qubit systems and quantum circuits; this is done for both single-excitation and multiexcitation encodings. Specific examples of spin chains, as well as static and dynamic systems of qubits, are mapped to quantum walks, and walks on hyperlattices and hypercubes are mapped to various gate systems. We also show how to map a quantum circuit performing the quantum Fourier transform, the key element of Shor's algorithm, to a quantum walk system doing the same. The results herein are an essential preliminary to a Hamiltonian formulation of quantum walks in which coupling to a dynamic quantum environment is included.

Hines, Andrew P. [Pacific Institute of Theoretical Physics and Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, V6T 1Z1 (Canada); Pacific Institute for the Mathematical Sciences, 1933 West Mall, University of British Columbia, Vancouver, British Columbia, V6T 1Z2 (Canada); Stamp, P. C. E. [Pacific Institute of Theoretical Physics and Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, V6T 1Z1 (Canada)

2007-06-15

395

IDEAL: Intrinsically Disordered proteins with Extensive Annotations and Literature  

PubMed Central

IDEAL, Intrinsically Disordered proteins with Extensive Annotations and Literature (http://www.ideal.force.cs.is.nagoya-u.ac.jp/IDEAL/), is a collection of knowledge on experimentally verified intrinsically disordered proteins. IDEAL contains manual annotations by curators on intrinsically disordered regions, interaction regions to other molecules, post-translational modification sites, references and structural domain assignments. In particular, IDEAL explicitly describes protean segments that can be transformed from a disordered state to an ordered state. Since in most cases they can act as molecular recognition elements upon binding of partner proteins, IDEAL provides a data resource for functional regions of intrinsically disordered proteins. The information in IDEAL is provided on a user-friendly graphical view and in a computer-friendly XML format. PMID:22067451

Fukuchi, Satoshi; Sakamoto, Shigetaka; Nobe, Yukiko; Murakami, Seiko D.; Amemiya, Takayuki; Hosoda, Kazuo; Koike, Ryotaro; Hiroaki, Hidekazu; Ota, Motonori

2012-01-01

396

Gate Fidelities, Quantum Broadcasting, and Assessing Experimental Realization  

E-print Network

We relate gate fidelities of experimentally realized quantum operations to the broadcasting property of their ideal operations, and show that the more parties a given quantum operation can broadcast to, the higher gate fidelities of its experimental realization are in general. This is shown by establishing the correspondence between two operational quantities, quantum state shareability and quantum broadcasting. This suggests that, to assess an experimental realization using gate fidelities, the worst case of realization such as noisy operations should be taken into account and then compared to obtained gate fidelities. In addition, based on the correspondence, we also translate results in quantum state shareability to their counterparts in quantum operations.

Hyang-Tag Lim; Young-Sik Ra; Yong-Su Kim; Yoon-Ho Kim; Joonwoo Bae

2011-06-29

397

Jarzynski equation for the expansion of a relativistic gas and black-body radiation  

NASA Astrophysics Data System (ADS)

Generalizing the work of Lua and Grosberg [R.C. Lua, A.Y. Grosberg, J. Phys. Chem. B 109 (2005) 6805], we verify the validity of the Jarzynski equation for the non-equilibrium expansion of an ideal relativistic gas and black-body radiation, respectively. The upper limit for the speed of the particles allows one to choose the parameters of the problem such that no multiple collisions need to be taken into account. Although related, the two cases considered differ from each other due to the quantum nature of photons. We show that bunching of photons is crucial for the Jarzynski equation to hold.

Nolte, Roman; Engel, Andreas

2009-09-01

398

Quantum-state steering in optomechanical devices  

E-print Network

We show that optomechanical systems in the quantum regime can be used to demonstrate EPR-type quantum entanglement between the optical field and the mechanical oscillator, via quantum-state steering. Namely, the conditional quantum state of the mechanical oscillator can be steered into different quantum states depending the choice made on which quadrature of the out-going field is to be measured via homodyne detection. More specifically, if quantum radiation pressure force dominates over thermal force, the oscillator's quantum state is steerable with a photodetection efficiency as low as 50%, approaching the ideal limit shown by Wiseman and Gambetta [Phys. Rev. Lett. {\\bf 108}, 220402 (2012)]. We also show that requirement for steerability is the same as those for achieving sub-Heisenberg state tomography using the same experimental setup.

Helge Mueller-Ebhardt; Haixing Miao; Stefan Danilishin; Yanbei Chen

2012-11-19

399

Cartilage-perichondrium: an ideal graft material?  

PubMed

Temporalis fascia has long been regarded as the ideal graft material for tympanic membrane repair. However it often does not seem to withstand negative middle ear pressure in the post operative period. Tragal cartilage with perichondrium would appear to be a better graft material with good hearing outcome. It can be obtained easily with cosmetically acceptable incision. In the present study, we have compared the graft properties of temporalis fascia verses tragal cartilage perichondrium with respect to healing, hearing and rate of post operative retraction or reperforation. 132 patients of chronic otitis media with pure conductive hearing loss were posted for tympanoplasty. Temporalis fascia graft was used in 71 patients and cartilage perichondrium (composite graft) was used in 61 patients. Post operative healing, hearing and rate of retraction or reperforation was compared for both the graft materials. All the patients were followed up for 2 years. Patients where temporalis fascia graft was used, 60 (84.5%) showed a good neotympanum, 7(9.85%) had reperforation and 5(7.04%) had retraction pockets. Patients where tragal cartilage perichondrium was used, 60(98.36%) showed a healed tympanic membrane and only 1(1.63%) had reperforation. None of the patients showed retraction pocket or cholestetoma. Postoperative hearing was accessed 6 months after surgery. Patients with temporalis fascia graft showed an air bone gap of less than 10 dB in 49 (82%) patients and more than 10 dB in 11 (18%) patients. Air bone gap closure with tragal cartilage perichondrium was less than 10 dB in 45 (78%) patients and more than 10 dB in 13 patients (22%). Tragal cartilage perichondrium (<0.5 mm) seems to be an ideal graft material for tympanic membrane in terms of postoperative healing and acoustic properties. It can easily withstand negative middle ear pressure which may have contributed to the development of otitis media and significantly affect healing outcomes in postoperative period. Tragal cartilage being composed of collagen type II is also physiologically similar to the nature of the tympanic membrane. PMID:23998021

Chhapola, Sunita; Matta, Inita

2012-09-01

400

Foundations of Nonlinear Dynamics or Real Dynamics, Ideal Dynamics, Unpredictable Dynamics and the "Schroedinger's Cat Paradox"  

E-print Network

The paper discusses the basic paradoxes of thermodynamics and quantum mechanics. The approaches to solution of these paradoxes are suggested. The first one relies on the influence of the external observer (environment), which disrupts the correlations in the system. The second one is based on the limits of self-knowledge of the system in case of both the external observer and the environment is included in the considered system. The concepts of Real Dynamics, Ideal Dynamics, and Unpredictable dynamics are introduced. The phenomenon of Life is contemplated from the point of view of these Dynamics.

Kupervasser Oleg

2005-08-18

401

Strong discontinuities in spatial stationary long-wave flows of an ideal incompressible fluid  

Microsoft Academic Search

Spatial stationary flows over an even bottom of a heavy ideal fluid with a free surface are considered. Jump relations for\\u000a flows with a strong discontinuity are studied. It is shown that the flow parameters behind the jump are defined by a certain\\u000a curve which is an analog of the (?, p) diagram in gas dynamics. A shock polar and

A. K. Khe

2009-01-01

402

Ideal bandpasses for type Ia supernova cosmology  

SciTech Connect

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

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

2005-10-24

403

Ideal timing of orchiopexy: a systematic review.  

PubMed

The ideal management of cryptorchidism is a highly debated topic within the field of pediatric surgery. The optimal timing of orchiopexy is particularly unclear, as existing literature reports mixed recommendations. The aim of this study was to determine, based on a systematic review, the most favorable age at which orchiopexy should be performed. We conducted a systematic search of MEDLINE, Embase, CINAHL, and the Cochrane Library to find relevant articles. Two researchers quality assessed each study using the following tools: AMSTAR (systematic reviews), Jadad (RCTs), and MINORS (non-RCTs). We developed a conclusion based on the highest quality studies. We found one relevant systematic review, one RCT, and 30 non-RCTs. Fertility potential was greatest when orchiopexy was performed before 1 year of age. Additionally, orchiopexy before 10–11 years may protect against the increased risk of testicular cancer associated with cryptorchidism. Orchiopexy should not be performed before 6 months of age, as testes may descend spontaneously during the first few months of life. The highest quality evidence recommends orchiopexy between 6 and 12 months of age. Surgery during this timeframe may optimize fertility potential and protect against testicular malignancy in children with cryptorchidism. PMID:24232174

Chan, Emily; Wayne, Carolyn; Nasr, Ahmed

2014-01-01

404

Parrondo games as lattice gas automata  

Microsoft Academic Search

Parrondo games are coin flipping games with the surprising property that alternating plays of two losing games can produce a winning game. We show that this phenomenon can be modelled by probabilistic lattice gas automata. Furthermore, motivated by the recent introduction of quantum coin flipping games, we show that quantum lattice gas automata provide an interesting definition for quantum Parrondo

David A. Meyer; Heather Blumer

2001-01-01

405

Parrondo Games as Lattice Gas Automata  

Microsoft Academic Search

Parrondo games are coin flipping games with the surprising property that alternating plays of two losing games can produce a winning game. We show that this phenomenon can be modelled by probabilistic lattice gas automata. Furthermore, motivated by the recent introduction of quantum coin flipping games, we show that quantum lattice gas automata provide an interesting definition for quantum Parrondo

David A. Meyer; Heather Blumer

2002-01-01

406

Molecular structures of free quinuclidine and its adducts with metal trihydrides, MH3 (M=B, Al or Ga), studied by gas-phase electron diffraction, X-ray diffraction and quantum chemical calculations.  

PubMed

The structure of quinuclidine, HC(CH(2)CH(2))(3)N, has been re-investigated by quantum chemical calculations and by gas-phase electron diffraction (GED). The GED data, together with published rotational constants, have been analysed using the SARACEN method to determine the most reliable structure (r(h1)) for the gaseous molecule. The structures of two adducts of quinuclidine with group 13 trihydride molecules, MH(3) (M=B, Al), have also been determined by GED and quantum chemical calculations. The effect of the coordination of these hydrides to the quinuclidine nitrogen atom has been investigated, and the structural changes and energetics of adduct formation are discussed. We also present the crystal structure of quinuclidine borane. PMID:17443261

Wann, Derek A; Blockhuys, Frank; Van Alsenoy, Christian; Robertson, Heather E; Himmel, Hans-Jörg; Tang, Christina Y; Cowley, Andrew R; Downs, Anthony J; Rankin, David W H

2007-05-01

407

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

SciTech Connect

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

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

2007-09-15

408

Quantum cloning  

E-print Network

The impossibility of perfectly copying (or cloning) an arbitrary quantum state is one of the basic rules governing the physics of quantum systems. The processes that perform the optimal approximate cloning have been found in many cases. These "quantum cloning machines" are important tools for studying a wide variety of tasks, e.g. state estimation and eavesdropping on quantum cryptography. This paper provides a comprehensive review of quantum cloning machines (both for discrete-dimensional and for continuous-variable quantum systems); in addition, it presents the role of cloning in quantum cryptography, the link between optimal cloning and light amplification via stimulated emission, and the experimental demonstrations of optimal quantum cloning.

Valerio Scarani; Sofyan Iblisdir; Nicolas Gisin; Antonio Acin

2005-11-09

409

Quantum Communication  

E-print Network

Quantum communication, and indeed quantum information in general, has changed the way we think about quantum physics. In 1984 and 1991, the first protocol for quantum cryptography and the first application of quantum non-locality, respectively, attracted a diverse field of researchers in theoretical and experimental physics, mathematics and computer science. Since then we have seen a fundamental shift in how we understand information when it is encoded in quantum systems. We review the current state of research and future directions in this new field of science with special emphasis on quantum key distribution and quantum networks.

Nicolas Gisin; Rob Thew

2007-03-27

410

Nonlinear Dynamics In Quantum Physics -- Quantum Chaos and Quantum Instantons  

E-print Network

We discuss the recently proposed quantum action - its interpretation, its motivation, its mathematical properties and its use in physics: quantum mechanical tunneling, quantum instantons and quantum chaos.

H. Kröger

2003-02-21

411

Quantum robots and quantum computers.  

National Technical Information Service (NTIS)

Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and systems that carry out experiments. The description of quantum computers is under acti...

P. Benioff

1998-01-01

412

Hamiltonian Description of Idealized Binary Geophysical Fluids.  

NASA Astrophysics Data System (ADS)

A Hamiltonian formulation for the dynamics and thermodynamics of a compressible, rotating, binary fluid subject to gravity is developed. Here, binary refers to the presence of two components of the fluid, such as solids dissolved in a liquid or gaseous and liquid water existing along with dry air. These fluids are idealized in that the influences of diffusion processes are ignored and the binary flow is restricted to a single velocity.The equations are presented in generic form applicable to an arbitrary binary geophysical flow. The relevant Poisson bracket satisfies Jacobi's identity. Three distinct Casimir invariants are described. The first reflects the conservation of entropy and concentration of the minor component. The second is a consequence of the conservation of the absolute circulation on curves formed by the intersection of surfaces of constant entropy with surfaces of constant concentration. The third is a generic potential vorticity of the form (·?)/. Here, is the absolute vorticity, is the total density of the fluid, and ? is any thermodynamic variable. For example, ? can be the pressure, density, temperature, or mixing ratio as well as the more common choice of potential temperature.Available energy of the system is defined locally in the finite-amplitude as well as in the small-amplitude limit. Both definitions are partitioned into available potential and available elastic energies.A linear stability analysis indicates that the fluid is statically stable provided the square of the sound speed is positive, the total density decreases with height, and the square of a suitably defined buoyancy frequency is positive.The formulation is applicable to a salty ocean and to a moist atmosphere. For the atmosphere, the full theory holds in the presence of either liquid water or ice in equilibrium with its vapor.

Bannon, Peter R.

2003-11-01

413

The atomic theory of division of semiring ideals  

Microsoft Academic Search

We consider two-sided ideals of semirings. More precisely, we study the theory of two-sided ideals in the signature consisting\\u000a of the predicate symbol ? and two function symbols that denote the right and left division of ideals. We prove that the set\\u000a of those atomic formulas in this signature that are valid for all semirings and all valuations is decidable.

A. E. Pentus; M. R. Pentus

2008-01-01

414

Derivations into duals of closed ideals of Banach algebras  

Microsoft Academic Search

Let $\\\\cal A$ be a Banach algebra. We study those closed ideals $I$ of $\\\\cal\\u000aA$ for which the first cohomology group of $\\\\cal A$ with coefficients in $I^*$\\u000ais trivial; i.e. $H^1(\\\\cal A,I^*)=\\\\{0\\\\}$. We investigate such closed ideals\\u000awhen $\\\\cal A$ is weakly amenable or biflat. Also we give some hereditary\\u000aproperties of ideal amenability.

M. Eshaghi Gordji; B. Hayati; S. A. R. Hosseiniun

2006-01-01

415

The significance of the Hansen Ideal space frame  

NASA Astrophysics Data System (ADS)

Known and unknown properties of Hansen Ideal coordinates are summarized. It is shown that the ideal space frame is a general and necessary component of basic celestial mechanics and astrodynamics, as well as of any theory of motion. A typical consequence is the intimate correlation of the Hansen frame with the Lagrange constraint within the method of the variation of the parameters. The use of observations in the ideal frame may allow conclusions on the intergalactic fundamental coordinate system.

Jochim, E. F. M.

2012-10-01

416

Experimental One-Way Quantum Computing  

E-print Network

Standard quantum computation is based on sequences of unitary quantum logic gates which process qubits. The one-way quantum computer proposed by Raussendorf and Briegel is entirely different. It has changed our understanding of the requirements for quantum computation and more generally how we think about quantum physics. This new model requires qubits to be initialized in a highly-entangled cluster state. From this point, the quantum computation proceeds by a sequence of single-qubit measurements with classical feedforward of their outcomes. Because of the essential role of measurement a one-way quantum computer is irreversible. In the one-way quantum computer the order and choices of measurements determine the algorithm computed. We have experimentally realized four-qubit cluster states encoded into the polarization state of four photons. We fully characterize the quantum state by implementing the first experimental four-qubit quantum state tomography. Using this cluster state we demonstrate the feasibility of one-way quantum computing through a universal set of one- and two-qubit operations. Finally, our implementation of Grover's search algorithm demonstrates that one-way quantum computation is ideally suited for such tasks.

P. Walther; K. J. Resch; T. Rudolph; E. Schenck; H. Weinfurter; V. Vedral; M. Aspelmeyer; A. Zeilinger

2005-03-14

417

On linear resolution of powers of an ideal  

E-print Network

In this paper we give a generalization of a result of Herzog, Hibi, and Zheng providing an upper bound for regularity of powers of an ideal. As the main result of the paper, we give a simple criterion in terms of Rees algebra of a given ideal to show that high enough powers of this ideal have linear resolution. We apply the criterion to two important ideals $J,J_{1}$ for which we show that $J^{k},$ and $J_{1}^{k}$ have linear resolution if and only if $k\

Lorestani, Keivan Borna

2008-01-01

418

Ideal amenability of Banach algebras on locally compact groups  

Microsoft Academic Search

In this paper we study the ideal amenability of Banach algebras. LetA be a Banach algebra and letI be a closed two-sided ideal inA, A isI-weakly amenable ifH\\u000a 1(A,I\\u000a *) = {0}. Further,A is ideally amenable ifA isI-weakly amenable for every closed two-sided idealI inA. We know that a continuous homomorphic image of an amenable Banach algebra is again amenable.

M. Eshaghi Gordji; S. A. R. Hosseiniun

2005-01-01

419

Rapid performance evaluation for ideal FROC and AFROC observers  

NASA Astrophysics Data System (ADS)

FROC and AFROC analyses are useful in medical imaging to characterize detection performance for the case of multiple lesions. We had previously developed1 ideal FROC and AFROC observers. Their performance is ideal in that they maximize the area or any partial area under the FROC or AFROC curve. Such observers could be useful in imaging system optimization or in assessing human observer efficiency. However, the performance evaluation of these ideal observers is impractically computationally complex. We propose 3 reasonable assumptions under which the ideal observers reduce approximately to a particular form of a scan-statistic observer. Performance for the "scan-statistic-reduced ideal observer" can be evaluated far more rapidly albeit with slight error than that of the originally proposed ideal observer. Through simulations, we confirm the accuracy of our approximate ideal observers. We also compare the performance of our approximate ideal observer with that of a conventional scan-statistic observer and show that the performance of our approximate ideal observer is significantly greater.

Liu, Bin; Khurd, Parmeshwar; Gindi, Gene

2010-02-01

420

Optimizing Nanoparticle Designs to Reach Ideal Light Absorption  

E-print Network

Ideal absorption describes a particular means of optimizing light-matter interactions with a host of potential applications. This work presents new analytic formulas and describes semi-analytical methods for the design of electric or magnetic ideal absorption in nanoparticles. These formulas indicate that ideal absorption is attainable in homogeneous spheres with known materials at specific sizes and frequencies. They also provide a means of designing core-shell particles to produce ideal absorption at virtually any frequency in the visible and near infrared range.

Grigoriev, Victor; Wenger, Jerome; Stout, Brian

2014-01-01

421

Optimizing Passive Quantum Clocks  

E-print Network

We describe protocols for passive atomic clocks based on quantum interrogation of the atoms. Unlike previous techniques, our protocols are adaptive and take advantage of prior information about the clock's state. To reduce deviations from an ideal clock, each interrogation is optimized by means of a semidefinite program for atomic state preparation and measurement whose objective function depends on the prior information. Our knowledge of the clock's state is maintained according to a Bayesian model that accounts for noise and measurement results. We implement a full simulation of a running clock with power-law noise models and find significant improvements by applying our techniques.

Michael Mullan; Emanuel Knill

2014-04-15

422

Optimizing passive quantum clocks  

NASA Astrophysics Data System (ADS)

We describe protocols for passive atomic clocks based on quantum interrogation of the atoms. Unlike previous techniques, our protocols are adaptive and take advantage of prior information about the clock's state. To reduce deviations from an ideal clock, each interrogation is optimized by means of a semidefinite program for atomic state preparation and measurement whose objective function depends on the prior information. Our knowledge of the clock's state is maintained according to a Bayesian model that accounts for noise and measurement results. We implement a full simulation of a running clock with power-law noise models and find significant improvements by applying our techniques.

Mullan, Michael; Knill, Emanuel

2014-10-01

423

Engineering of 3D self-directed quantum dot ordering in multilayer InGaAs\\/GaAs nanostructures by means of flux gas composition  

Microsoft Academic Search

Lateral ordering of InGaAs quantum dots on the GaAs (001) surface has been achieved in earlier reports, resembling an anisotropic pattern. In this work, we present a method of breaking the anisotropy of ordered quantum dots (QDs) by changing the growth environment. We show experimentally that using As2 molecules instead of As4 as a background flux is efficient in controlling

P. M. Lytvyn; Yu I. Mazur; E. Marega Jr.; V. G. Dorogan; V. P. Kladko; M. V. Slobodian; V. V. Strelchuk; M. L. Hussein; M. E. Ware; G. J. Salamo

2008-01-01

424

High-Performance Quantum Cascade Lasers Grown by MetalOrganic Vapor Phase Epitaxy and Their Applications to Trace Gas Sensing  

Microsoft Academic Search

We present an overview of our results on the design, material growth, device characterization, and spectroscopic applications of MOVPE-grown quantum cascade lasers (QCLs). These devices are capable of room-temperature (RT) continuous-wave operation and high power emission. The first section focuses on growth of laser material, device fabrication, and quantum design The second section discusses RT pulsed operation, in particular the

Mariano Troccoli; Laurent Diehl; David P. Bour; Scott W. Corzine; Nanfang Yu; Christine Y. Wang; Mikhail A. Belkin; Gloria Hofler; Rafal Lewicki; Gerard Wysocki; Frank K. Tittel; Federico Capasso

2008-01-01

425

Quantum coding  

Microsoft Academic Search

A theorem is proven for quantum information theory that is analogous to the noiseless coding theorem of classical information theory. In the quantum result, the von Neumann entropy S of the density operator describing an ensemble of pure quantum signal states is equal to the number of spin-1\\/2 systems (``quantum bits'' or ``qubits'') necessary to represent the signal faithfully. The

Benjamin Schumacher

1995-01-01

426

Quantum telecloning  

NASA Astrophysics Data System (ADS)

A quantum telecloning process combining quantum teleportation and optimal quantum cloning from one input to M outputs is presented. The scheme relies on the establishment of particular multiparticle entangled states, which function as multiuser quantum information channels. The entanglement structure of these states is analyzed and shown to be crucial for this type of information processing.

Plenio, M. B.; Murao, M.; Jonathan, D.; Vedral, V.

1999-03-01

427

Increased body satisfaction after exposure to thin ideal children's television in young girls showing thin ideal internalisation  

Microsoft Academic Search

This study tested the direct effect of watching thin ideal children's television on body satisfaction in preadolescent girls (6–8 years old). A within-subject design was used in which girls (N?=?51) were tested three times. They watched television clips in random order containing either (1) thin ideal animated characters or (2) animated characters with no thin ideal features or (3) ‘real’

Doeschka J. Anschutz; Rutger C. M. E. Engels; Tatjana Van Strien

2012-01-01

428

Increased body satisfaction after exposure to thin ideal children's television in young girls showing thin ideal internalisation  

Microsoft Academic Search

This study tested the direct effect of watching thin ideal children's television on body satisfaction in preadolescent girls (6–8 years old). A within-subject design was used in which girls (N?=?51) were tested three times. They watched television clips in random order containing either (1) thin ideal animated characters or (2) animated characters with no thin ideal features or (3) ‘real’

Doeschka J. Anschutz; Rutger C. M. E. Engels; Tatjana Van Strien

2011-01-01

429

Realizable receivers for discriminating coherent and multicopy quantum states near the quantum limit  

NASA Astrophysics Data System (ADS)

We derive the quantum limit on the error probability exponent for discriminating any M multimode coherent states of light and show that it is four times that of an ideal heterodyne receiver for the same signal set. We then propose a receiver that achieves the quantum limit using auxiliary coherent-state fields, beam splitters, and single-photon detectors. The performance of the receiver is compared to standard measurements for various imaging and communication tasks. A related receiver for discriminating arbitrary multicopy pure quantum states is shown to achieve the M-ary quantum Chernoff exponent and does so using only local operations and classical communication.

Nair, Ranjith; Guha, Saikat; Tan, Si-Hui

2014-03-01

430

A free-space test range for global quantum key distribution feasibility studies  

Microsoft Academic Search

Quantum cryptographic systems employ secret keys exchanged between two parties in the form of a stream of polarisation- or phase-encoded single photons. Under ideal conditions the absolute security of the quantum key is guaranteed by the laws of quantum physics, since any attempt at eavesdropping will introduce gross bit errors which will be quickly detected by the legitimate parties to

P. J. Edwards; W. N. Cheung; L. O. Barbopoulos; G. Ganesharajah; P. Lynam; B. Greene; J. Luck

2000-01-01

431

Quantum Machines  

E-print Network

We discuss quantum information processing machines. We start with single purpose machines that either redistribute quantum information or identify quantum states. We then move on to machines that can perform a number of functions, with the function they perform being determined by a program, which is itself a quantum state. Examples of both deterministic and probabilistic programmable machines are given, and we conclude with a discussion of the utility of quantum programs.

Mark Hillery; Vladimir Buzek

2009-03-24

432

Quantum ontologies  

SciTech Connect

Quantum ontologies are conceptions of the constitution of the universe that are compatible with quantum theory. The ontological orientation is contrasted to the pragmatic orientation of science, and reasons are given for considering quantum ontologies both within science, and in broader contexts. The principal quantum ontologies are described and evaluated. Invited paper at conference: Bell's Theorem, Quantum Theory, and Conceptions of the Universe, George Mason University, October 20-21, 1988. 16 refs.

Stapp, H.P.

1988-12-01

433

Structure characterisation method for ideal and non-ideal twisted plywoods.  

PubMed

The twisted plywood architecture, known as the Bouligand structure, is a ubiquitous biological and synthetic fibrous composite structure, analogous to that of cholesteric liquid crystals. Twisted plywoods can show ideal or non-ideal structures and are formed via equilibrium or non-equilibrium liquid crystal self-assembly processes. A key to the structure characterisation of plywood films is the specification of the local and global helix vector h(x) and pitch p(x) of the cholesteric order. Previous extensive work demonstrated that oblique cuts of the plywood give rise to arc-patterns that depend both on the unknown incision angle ? and the unknown pitch p(x), thus making the precise 3D cholesteric reconstruction ambiguous. In this paper we present an efficient method based on geometric modelling and new visualization software that determines unambiguously the cholesteric pitch under spatially homogeneous and heterogeneous conditions. The method is applied to films that display two-pitch and spatially non-homogenous structures, as sometimes observed under equilibrium and non-equilibrium self-assembly. The method can be extended to other biological materials such as cornea-like, cylindrical, and various cuticle plywoods. PMID:25342518

Aguilar Gutierrez, Oscar F; Rey, Alejandro D

2014-12-21

434

The Mechanism of Quantum Computation  

Microsoft Academic Search

I provide an alternative way of seeing quantum computation. First, I describe an idealized classical problem solving machine\\u000a whose coordinates are submitted to a nonfunctional relation representing all the problem constraints; moving an input part,\\u000a reversibly and nondeterministically produces a solution through a many body interaction. The machine can be considered the\\u000a many body generalization of another perfect machine, the

Giuseppe Castagnoli

2008-01-01

435

Abstract: Research in solidstate "artificial atoms" seeks to merge atomic physics and condensed matter nanotechnology to tackle outstanding problems in the life, physical, and information sciences. An ideal  

E-print Network

and nanoscale MRI with widefield optical readout. Biography: Acosta is a research scientist at Google [x. An ideal artificial atom has the coherent spin and optical properties of dilute atomic vapor state, and spinselective optical transitions even at room temperature. For quantum information

New Mexico, University of

436

Quantum Computer Games: Quantum Minesweeper  

ERIC Educational Resources Information Center

The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical…

Gordon, Michal; Gordon, Goren

2010-01-01

437

Quantum CPU and Quantum Simulating  

E-print Network

Making use of an universal quantum network or QCPU proposed by me [6], some special quantum networks for simulating some quantum systems are given out. Specially, it is obtained that the quantum network for the time evolution operator which can simulate, in general, Schr\\"odinger equation.

An Min Wang

1999-10-22

438

Quantum CPU and Quantum Algorithm  

E-print Network

Making use of an universal quantum network -- QCPU proposed by me\\upcite{My1}, it is obtained that the whole quantum network which can implement some the known quantum algorithms including Deutsch algorithm, quantum Fourier transformation, Shor's algorithm and Grover's algorithm.

An Min Wang

1999-10-22

439

Games and the Impossibility of Realizable Ideal Functionality  

E-print Network

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

Paris-Sud XI, Université de

440

A Typology of Men's Conceptualizations of Ideal Masculinity in Advertising  

Microsoft Academic Search

:This study explores men's conceptualizations of ideal masculinity in advertising. Specifically, this research uses a qualitative approach to examine a segment of men who fall into the Generation X cohort. These men, many of whom are Caucasian and single, are largely educated, from the Midwest, and outwardly heterosexual. Exploratory findings reveal the salience of eight themes of ideal masculinity. These

Linda Tuncay Zayer

2010-01-01

441

A Typology of Men's Conceptualizations of Ideal Masculinity in Advertising  

Microsoft Academic Search

This study explores men's conceptualizations of ideal masculinity in advertising. Specifically, this research uses a qualitative approach to examine a segment of men who fall into the Generation X cohort. These men, many of whom are Caucasian and single, are largely educated, from the Midwest, and outwardly heterosexual. Exploratory findings reveal the salience of eight themes of ideal masculinity. These

Linda Tuncay Zayer

2010-01-01

442

Female “Thin Ideal” Media Images and Boys' Attitudes Toward Girls  

Microsoft Academic Search

Both boys and girls are exposed repeatedly to “thin-ideal” images in the media, that is, images of unrealistically thin and attractive women. As yet, however, little research has examined the impact of these images on boys. In the present study we investigated the effect of exposure to televised thin-ideal images on boys' attitudes toward girls. The participants were 354 boys

Duane A. Hargreaves; Marika Tiggemann

2003-01-01

443

Your Ideal Silhouette. Courseware Evaluation for Vocational and Technical Education.  

ERIC Educational Resources Information Center

This courseware evaluation rates the "Your Ideal Silhouette" program developed by Your Image, Inc. This program (not contained in this document) uses the computer to identify figure faults and illustrate personalized corrective style lines to achieve the ideal silhouette. Part A describes the program in terms of subject area (textiles and…

Tierney, Margaret S.; And Others

444

Ideal Free Distribution (IFD) Pattern: Consumers across Resource Patches  

E-print Network

Ideal Free Distribution (IFD) Pattern: Consumers across Resource Patches Ideal: Information-matching Rule IFD Distribution of consumers follows resource distribution Same for different total numbers of consumers (?) #12;Sum ki = 9 ki/9 = 1/18, 4/18, 5/18, 8/18 By input-matching: 72(ki/9) = 4, 16, 20, 32

Caraco, Thomas

445

WEIGHTED BIG LIPSCHITZ ALGEBRAS OF ANALYTIC FUNCTIONS AND CLOSED IDEALS.  

E-print Network

Lipschitz algebras of analytic functions. 1. Introduction. Let H be the space of all bounded analytic the structure of the closed ideals in some separable Banach algebras of analytic functions in D, we refer of closed ideals in nonseparable Banach algebras of analytic functions seems much more difficult

Boyer, Edmond

446

Education, Experience and Discrepant Self/Ideal. Counselor Concepts.  

ERIC Educational Resources Information Center

A sample of 204 counseling students and counselors with differing levels of experience and education from Utah colleges, universities, and public schools was asked to rate themselves and the ideal counselor on 38 semantic differential scales. Discrepancy scores derived from self-ideal differences were analyzed and found to support the hypotheses…

Johnson, Richard W.

447

The "Body Beautiful": English Adolescents' Images of Ideal Bodies.  

ERIC Educational Resources Information Center

Two studies examine qualities capturing adolescents' images of ideal bodies for both genders. Data from questionnaires and discussions of photographs indicate that body-image ideals are multidimensional, show systematic gender differences, and become more conventional with age. Adolescents' own body mass links systematically to body-image…

Dittmar, Helga; Lloyd, Barbara; Dugan, Shaun; Halliwell, Emma; Jacobs, Neil; Cramer, Helen

2000-01-01

448

An introduction to quantum probability, quantum mechanics, and quantum computation  

E-print Network

An introduction to quantum probability, quantum mechanics, and quantum computation Greg Kuperberg". Recently quantum computation has entered as a new reason for both mathematicians and computer scientists deterministic algorithms for some computational problems, quantum algorithms can be moderately faster

Thomases, Becca

449

Lecture notes on Optical Quantum Computing  

E-print Network

A quantum computer is a machine that can perform certain calculations much faster than a classical computer by using the laws of quantum mechanics. Quantum computers do not exist yet, because it is extremely difficult to control quantum mechanical systems to the necessary degree. What is more, we do at this moment not know which physical system is the best suited for making a quantum computer (although we have some ideas). It is likely that a mature quantum information processing technology will use (among others) light, because photons are ideal carriers for quantum information. These notes are an expanded version of the five lectures I gave on the possibility of making a quantum computer using light, at the Summer School in Theoretical Physics in Durban, 14-24 January, 2007. There are quite a few proposals using light for quantum computing, and I can highlight only a few here. I will focus on photonic qubits, and leave out continuous variables completely. I assume that the reader is familiar with basic quantum mechanics and introductory quantum computing.

Pieter Kok

2007-05-29

450

Five Lectures on Optical Quantum Computing  

NASA Astrophysics Data System (ADS)

A quantum computer is a machine that can perform certain calculations much faster than a classical computer by using the laws of quantum mechanics. Quantum computers do not exist yet, because it is extremely difficult to control quantum mechanical systems to the necessary degree. What is more, we do at this moment not know which physical system is the best suited for making a quantum computer (although we have some ideas). It is likely that a mature quantum information processing technology will use (among others) light, because photons are ideal carriers for quantum information. These notes are an expanded version of the five lectures I gave on the possibility of making a quantum computer using light, at the Summer School in Theoretical Physics in Durban, 14-24 January, 2007. There are quite a few proposals using light for quantum computing, and I can highlight only a few here. I will focus on photonic qubits, and leave out continuous variables completely.1 I assume that the reader is familiar with basic quantum mechanics and introductory quantum computing.

Kok, Pieter

451

Experimental quantum imaging exploiting multimode spatial correlation of twin beams  

SciTech Connect

Properties of quantum states have disclosed new and revolutionary technologies, ranging from quantum information to quantum imaging. This last field is intended to overcome the limits of classical imaging by exploiting specific properties of quantum states of light. One of the most interesting proposed schemes exploits spatial quantum correlations between twin beams for realizing sub-shot-noise imaging of weakly absorbing objects, leading ideally to a noise-free imaging. Here we discuss in detail the experimental realization of this scheme, showing its capability to reach a larger signal-to-noise ratio with respect to classical imaging methods and therefore its potential for future practical applications.

Brida, Giorgio; Genovese, Marco; Meda, Alice; Berchera, Ivano Ruo [Istituto Nazionale di Ricerca Metrologica (INRIM), strada delle Cacce 91, I-10135 Torino (Italy)

2011-03-15

452

Quantum annealing with manufactured spins.  

PubMed

Many interesting but practically intractable problems can be reduced to that of finding the ground state of a system of interacting spins; however, finding such a ground state remains computationally difficult. It is believed that the ground state of some naturally occurring spin systems can be effectively attained through a process called quantum annealing. If it could be harnessed, quantum annealing might improve on known methods for solving certain types of problem. However, physical investigation of quantum annealing has been largely confined to microscopic spins in condensed-matter systems. Here we use quantum annealing to find the ground state of an artificial Ising spin system comprising an array of eight superconducting flux quantum bits with programmable spin-spin couplings. We observe a clear signature of quantum annealing, distinguishable from classical thermal annealing through the temperature dependence of the time at which the system dynamics freezes. Our implementation can be configured in situ to realize a wide variety of different spin networks, each of which can be monitored as it moves towards a low-energy configuration. This programmable artificial spin network bridges the gap between the theoretical study of ideal isolated spin networks and the experimental investigation of bulk magnetic samples. Moreover, with an increased number of spins, such a system may provide a practical physical means to implement a quantum algorithm, possibly allowing more-effective approaches to solving certain classes of hard combinatorial optimization problems. PMID:21562559

Johnson, M W; Amin, M H S; Gildert, S; Lanting, T; Hamze, F; Dickson, N; Harris, R; Berkley, A J; Johansson, J; Bunyk, P; Chapple, E M; Enderud, C; Hilton, J P; Karimi, K; Ladizinsky, E; Ladizinsky, N; Oh, T; Perminov, I; Rich, C; Thom, M C; Tolkacheva, E; Truncik, C J S; Uchaikin, S; Wang, J; Wilson, B; Rose, G

2011-05-12

453

Moral identity as moral ideal self: links to adolescent outcomes.  

PubMed

The purposes of this study were to conceptualize moral identity as moral ideal self, to develop a measure of this construct, to test for age and gender differences, to examine links between moral ideal self and adolescent outcomes, and to assess purpose and social responsibility as mediators of the relations between moral ideal self and outcomes. Data came from a local school sample (Data Set 1: N = 510 adolescents; 10-18 years of age) and a national online sample (Data Set 2: N = 383 adolescents; 15-18 years of age) of adolescents and their parents. All outcome measures were parent-report (Data Set 1: altruism, moral personality, aggression, and cheating; Data Set 2: environmentalism, school engagement, internalizing, and externalizing), whereas other variables were adolescent-report. The 20-item Moral Ideal Self Scale showed good reliability, factor structure, and validity. Structural equation models demonstrated that, even after accounting for moral identity internalization, in Data Set 1 moral ideal self positively predicted altruism and moral personality and negatively predicted aggression, whereas in Data Set 2 moral ideal self positively predicted environmentalism and negatively predicted internalizing and externalizing symptoms. Further, purpose and social responsibility mediated most relations between moral ideal self and the outcomes in Data Set 2. Moral ideal self was unrelated to age but differentially predicted some outcomes across age. Girls had higher levels of moral ideal self than boys, although moral identity did not differentially predict outcomes between genders. Thus, moral ideal self is a salient element of moral identity and may play a role in morally relevant adolescent outcomes. PMID:23895167

Hardy, Sam A; Walker, Lawrence J; Olsen, Joseph A; Woodbury, Ryan D; Hickman, Jacob R

2014-01-01

454

Quantum Algorithms  

E-print Network

This article surveys the state of the art in quantum computer algorithms, including both black-box and non-black-box results. It is infeasible to detail all the known quantum algorithms, so a representative sample is given. This includes a summary of the early quantum algorithms, a description of the Abelian Hidden Subgroup algorithms (including Shor's factoring and discrete logarithm algorithms), quantum searching and amplitude amplification, quantum algorithms for simulating quantum mechanical systems, several non-trivial generalizations of the Abelian Hidden Subgroup Problem (and related techniques), the quantum walk paradigm for quantum algorithms, the paradigm of adiabatic algorithms, a family of ``topological'' algorithms, and algorithms for quantum tasks which cannot be done by a classical computer, followed by a discussion.

Michele Mosca

2008-08-04

455

Interacting Ions in Biophysics: Real is not Ideal  

PubMed Central

Ions in water are important throughout biology, from molecules to organs. Classically, ions in water were treated as ideal noninteracting particles in a perfect gas. Excess free energy of each ion was zero. Mathematics was not available to deal consistently with flows, or interactions with other ions or boundaries. Nonclassical approaches are needed because ions in biological conditions flow and interact. The concentration gradient of one ion can drive the flow of another, even in a bulk solution. A variational multiscale approach is needed to deal with interactions and flow. The recently developed energetic variational approach to dissipative systems allows mathematically consistent treatment of the bio-ions Na+, K+, Ca2+, and Cl? as they interact and flow. Interactions produce large excess free energy that dominate the properties of the high concentration of ions in and near protein active sites, ion channels, and nucleic acids: the number density of ions is often >10 M. Ions in such crowded quarters interact strongly with each other as well as with the surrounding protein. Nonideal behavior found in many experiments has classically been ascribed to allosteric interactions mediated by the protein and its conformation changes. The ion-ion interactions present in crowded solutions—independent of conformation changes of the protein—are likely to change the interpretation of many allosteric phenomena. Computation of all atoms is a popular alternative to the multiscale approach. Such computations involve formidable challenges. Biological systems exist on very different scales from atomic motion. Biological systems exist in ionic mixtures (like extracellular and intracellular solutions), and usually involve flow and trace concentrations of messenger ions (e.g., 10?7 M Ca2+). Energetic variational methods can deal with these characteristic properties of biological systems as we await the maturation and calibration of all-atom simulations of ionic mixtures and divalents. PMID:23663828

Eisenberg, Bob

2013-01-01

456

Genetic and Environmental Influences on Thin-Ideal Internalization  

PubMed Central

Objective Current research on the etiology of thin-ideal internalization focuses on psychosocial influences (e.g., media exposure). The possibility that genetic influences also account for variance in thin-ideal internalization has never been directly examined. This study used a twin design to estimate genetic effects on thin-ideal internalization and examine if environmental influences are primarily shared or nonshared in origin. Method Participants were 343 post-pubertal female twins (ages 12–22; M=17.61) from the Michigan State University Twin Registry. Thin-ideal internalization was assessed using the Sociocultural Attitudes toward Appearance Questionniare-3. Results Twin modeling suggested significant additive genetic and nonshared environmental influences on thin-ideal internalization. Shared environmental influences were small and non-significant. Discussion Although prior research focused on psychosocial factors, genetic influences on thin-ideal internalization were significant and moderate in magnitude. Research is needed to investigate possible interplay between genetic and nonshared environmental factors in the development of thin-ideal internalization. PMID:23034902

Suisman, Jessica L.; O'Connor, Shannon M.; Sperry, Steffanie; Thompson, J. Kevin; Keel, Pamela K.; Burt, S. Alexandra; Neale, Michael; Boker, Steven; Sisk, Cheryl; Klump, Kelly L.

2012-01-01

457

Quantum Computation  

E-print Network

In the last few years, theoretical study of quantum systems serving as computational devices has achieved tremendous progress. We now have strong theoretical evidence that quantum computers, if built, might be used as a dramatically powerful computational tool. This review is about to tell the story of theoretical quantum computation. I left out the developing topic of experimental realizations of the model, and neglected other closely related topics which are quantum information and quantum communication. As a result of narrowing the scope of this paper, I hope it has gained the benefit of being an almost self contained introduction to the exciting field of quantum computation. The review begins with background on theoretical computer science, Turing machines and Boolean circuits. In light of these models, I define quantum computers, and discuss the issue of universal quantum gates. Quantum algorithms, including Shor's factorization algorithm and Grover's algorithm for searching databases, are explained. I will devote much attention to understanding what the origins of the quantum computational power are, and what the limits of this power are. Finally, I describe the recent theoretical results which show that quantum computers maintain their complexity power even in the presence of noise, inaccuracies and finite precision. I tried to put all results in their context, asking what the implications to other issues in computer science and physics are. In the end of this review I make these connections explicit, discussing the possible implications of quantum computation on fundamental physical questions, such as the transition from quantum to classical physics.

Dorit Aharonov

1998-12-15

458

Voltage-controlled electron tunneling from a single self-assembled quantum dot embedded in a two-dimensional-electron-gas-based photovoltaic cell  

E-print Network

that our devices can operate as 2DEG-based QD photovoltaic cells and conclude by proposing two optical levels in self-assembled quantum dots (QDs) has motivated research into the incorpo- ration of these so been used to measure electrically the coherent optical manipulation of a QD two-level system.6,7 Here

Steiner, Ullrich

459

Quantum Histories and Quantum Gravity  

E-print Network

This paper reviews the histories approach to quantum mechanics. This discussion is then applied to theories of quantum gravity. It is argued that some of the quantum histories must approximate (in a suitable sense) to classical histories, if the correct classical regime is to be recovered. This observation has significance for the formulation of new theories (such as quantum gravity theories) as it puts a constraint on the kinematics, if the quantum/classical correspondence principle is to be preserved. Consequences for quantum gravity, particularly for Lorentz symmetry and the idea of "emergent geometry", are discussed.

Joe Henson

2009-01-26

460

Quantum Robots and Quantum Computers  

E-print Network

Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and experiments. The description of quantum computers is under active development. No description of systems to carry out experiments has been given. A small step in this direction is taken here by giving a description of quantum robots as mobile systems with on board quantum computers that interact with environments. Some properties of these systems are discussed. A specific model based on the literature descriptions of quantum Turing machines is presented.

Paul Benioff

1997-06-04

461

Quantum robots and quantum computers  

SciTech Connect

Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and systems that carry out experiments. The description of quantum computers is under active development. No description of systems to carry out experiments has been given. A small step in this direction is taken here by giving a description of quantum robots as mobile systems with on board quantum computers that interact with different environments. Some properties of these systems are discussed. A specific model based on the literature descriptions of quantum Turing machines is presented.

Benioff, P.

1998-07-01

462

Quantum Darwinism  

SciTech Connect

Quantum Darwinism - proliferation, in the environment, of multiple records of selected states of the system (its information-theoretic progeny) - explains how quantum fragility of individual state can lead to classical robustness of their multitude.

Zurek, Wojciech H [Los Alamos National Laboratory

2008-01-01

463

Quantum Games  

NSDL National Science Digital Library

Scientists studying quantum computation offer new perspectives on coin tossing, chess, and game theory. Theorists intend to apply the peculiarities of quantum behavior to game theory, two previously unrelated fields. These researchers propose that the possibility of a mixed state permits quantum-game strategies that in theory can be more successful than conventional ones. This new type of modeling using quantum computers could greatly affect fields such as economics, international relations, and computer science.

Peterson, Ivars

2007-03-03

464

I, Quantum Robot: Quantum Mind control on a Quantum Computer  

E-print Network

The logic which describes quantum robots is not orthodox quantum logic, but a deductive calculus which reproduces the quantum tasks (computational processes, and actions) taking into account quantum superposition and quantum entanglement. A way toward the realization of intelligent quantum robots is to adopt a quantum metalanguage to control quantum robots. A physical implementation of a quantum metalanguage might be the use of coherent states in brain signals.

Paola Zizzi

2008-12-25

465

Quantum Teleportation  

E-print Network

In the framework of an algebraic approach, we consider a quantum teleportation procedure. It turns out that using the quantum measurement nonlocality hypothesis is unnecessary for describing this procedure. We study the question of what material objects are information carriers for quantum teleportation.

D. A. Slavnov

2009-05-13

466

Quantum Chromodynamics  

E-print Network

Quantum chromodynamics is the quantum gauge field theory that describes the strong interactions. This article reviews the basic structure, successes and challenges of quantum chromodynamics as it manifests itself at short and long distances, including the concepts of asymptotic freedom, confinement and infrared safety.

George Sterman

2005-12-27

467

Quantum Physics  

Microsoft Academic Search

In Quantum Mechanics operators must be hermitian and, in a direct product space, symmetric. These properties are saved by Lie algebra operators but not by those of quantum algebras. A possible correspondence between observables and quantum algebra operators is suggested by extending the definition of matrix el- ements of a physical observable, including the eventual projection on the appro- priate

E. Celeghini; M. A. del Olmo

1969-01-01

468

Quantum Metrology  

Microsoft Academic Search

We point out a general framework that encompasses most cases in which quantum effects enable an increase in precision when estimating a parameter (quantum metrology). The typical quantum precision enhancement is of the order of the square root of the number of times the system is sampled. We prove that this is optimal, and we point out the different strategies

Vittorio Giovannetti; Seth Lloyd; Lorenzo Maccone

2006-01-01

469

Quantum tic-tac-toe: A teaching metaphor for superposition in quantum mechanics  

NASA Astrophysics Data System (ADS)

Quantum tic-tac-toe was developed as a metaphor for the counterintuitive nature of superposition exhibited by quantum systems. It offers a way of introducing quantum physics without advanced mathematics, provides a conceptual foundation for understanding the meaning of quantum mechanics, and is fun to play. A single superposition rule is added to the child's game of classical tic-tac-toe. Each move consists of a pair of marks subscripted by the number of the move ("spooky" marks) that must be placed in different squares. When a measurement occurs, one spooky mark becomes real and the other disappears. Quantum tic-tac-toe illustrates a number of quantum principles including states, superposition, collapse, nonlocality, entanglement, the correspondence principle, interference, and decoherence. The game can be played on paper or on a white board. A Web-based version provides a refereed playing board to facilitate the mechanics of play, making it ideal for classrooms with a computer projector.

Goff, Allan

2006-11-01

470

Ideal Based Cyber Security Technical Metrics for Control Systems  

SciTech Connect

Much of the world's critical infrastructure is at risk from attack through electronic networks connected to control systems. Security metrics are important because they provide the basis for management decisions that affect the protection of the infrastructure. A cyber security technical metric is the security relevant output from an explicit mathematical model that makes use of objective measurements of a technical object. A specific set of technical security metrics are proposed for use by the operators of control systems. Our proposed metrics are based on seven security ideals associated with seven corresponding abstract dimensions of security. We have defined at least one metric for each of the seven ideals. Each metric is a measure of how nearly the associated ideal has been achieved. These seven ideals provide a useful structure for further metrics development. A case study shows how the proposed metrics can be applied to an operational control system.

W. F. Boyer; M. A. McQueen

2007-10-01

471

2. SECTIONAL BOILER '#4 IDEAL RED FLASH.' Hot Springs ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. SECTIONAL BOILER '#4 IDEAL RED FLASH.' - Hot Springs National Park, Bathhouse Row, Ozark Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

472

Arctic Ocean circulation in an idealized numerical model  

E-print Network

The mid-to-deep Arctic Ocean is generally characterized by a cyclonic circulation, contained along shelves and ridges. Here we analyze the general Arctic circulation using an idealized numerical model consisting of a ...

Sugimura, Peter Joseph

2008-01-01

473

Approaching the ideal elastic limit of metallic glasses  

E-print Network

The ideal elastic limit is the upper bound to the stress and elastic strain a material can withstand. This intrinsic property has been widely studied for crystalline metals, both theoretically and experimentally. For ...

Tian, Lin

474

"Ideal" Schedule for BA Earth Sciences Semester 1 Semester 2  

E-print Network

"Ideal" Schedule for BA Earth Sciences 11/06 Semester 1 Semester 2 ESCI 400 & 401 ESCI 402 MATH additional courses in earth sciences and other science and math courses. WI ­ All students must take four

Pringle, James "Jamie"

475

Second-order synchrosqueezing transform or invertible reassignment? Towards ideal  

E-print Network

Second-order synchrosqueezing transform or invertible reassignment? Towards ideal time of the modes. These two new transformations thus provide the benefits of both the synchrosqueezing transform transformations, and illustrate their differences. Index Terms time-frequency, reassignment, synchrosqueezing, AM

Paris-Sud XI, Université de

476

Measurable Control System Security through Ideal Driven Technical Metrics  

SciTech Connect

The Department of Homeland Security National Cyber Security Division supported development of a small set of security ideals as a framework to establish measurable control systems security. Based on these ideals, a draft set of proposed technical metrics was developed to allow control systems owner-operators to track improvements or degradations in their individual control systems security posture. The technical metrics development effort included review and evaluation of over thirty metrics-related documents. On the bases of complexity, ambiguity, or misleading and distorting effects the metrics identified during the reviews were determined to be weaker than necessary to aid defense against the myriad threats posed by cyber-terrorism to human safety, as well as to economic prosperity. Using the results of our metrics review and the set of security ideals as a starting point for metrics development, we identified thirteen potential technical metrics - with at least one metric supporting each ideal. Two case study applications of the ideals and thirteen metrics to control systems were then performed to establish potential difficulties in applying both the ideals and the metrics. The case studies resulted in no changes to the ideals, and only a few deletions and refinements to the thirteen potential metrics. This led to a final proposed set of ten core technical metrics. To further validate the security ideals, the modifications made to the original thirteen potential metrics, and the final proposed set of ten core metrics, seven separate control systems security assessments performed over the past three years were reviewed for findings and recommended mitigations. These findings and mitigations were then mapped to the security ideals and metrics to assess gaps in their coverage. The mappings indicated that there are no gaps in the security ideals and that the ten core technical metrics provide significant coverage of standard security issues with 87% coverage. Based on the two case studies and evaluation of the seven assessments, the security ideals demonstrated their value in guiding security thinking. Further, the final set of core technical metrics has been demonstrated to be both usable in the control system environment and provide significant coverage of standard security issues.

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

2008-01-01

477

Feminist Ideals for a Healthy Female Adolescent Sexuality: A Critique  

Microsoft Academic Search

This paper explores the ideals of healthy sexuality for teenage girls in the U.S. proposed by feminist theorists and researchers.\\u000a Current ideals emphasize desire, pleasure, and subjectivity, and appear to be a response to three historically problematic\\u000a areas for women and girls: objectification; abuse and victimization; and stereotypes of female passivity. There are, however,\\u000a several problems with using these qualities

Sharon Lamb

2010-01-01