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1

STP Ideal Quantum Gas Program  

NSDL National Science Digital Library

The STP IdealQuantumGas program is a simulation of an ideal quantum gas in equilibrium with a heat bath. The program computes the density of states, particle distribution function, and energy occupancy diagram. The default system is a three-dimensional ideal Fermi gas of N=100 particles at temperature T=10. STP IdealQuantumGas 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_IdealQuantumGas.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

2009-03-09

2

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

3

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

PubMed

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

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

2014-01-01

4

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

PubMed Central

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

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

2014-01-01

5

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

6

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.

7

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

8

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

9

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

10

ChemTeacher: Ideal Gas Law  

NSDL National Science Digital Library

ChemTeacher compiles background information, videos, articles, demonstrations, worksheets and activities for high school teachers to use in their classrooms. The Ideal Gas Law page includes resources for teaching students about the definition and applications of the Ideal Gas Law.

2011-01-01

11

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

12

Quantum noise in ideal operational amplifiers  

E-print Network

We consider a model of quantum measurement built on an ideal operational amplifier operating in the limit of infinite gain, infinite input impedance and null output impedance and with a feddback loop. We evaluate the intensity and voltage noises which have to be added to the classical amplification equations in order to fulfill the requirements of quantum mechanics. We give a description of this measurement device as a quantum network scattering quantum fluctuations from input to output ports.

Jean-Michel Courty; Francesca Grassia; Serge Reynaud

1998-11-24

13

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

14

Generalized Ideal Gas Equations for Structureful Universe  

Microsoft Academic Search

We have derived generalized ideal gas equations for a structureful universe consistingof all forms of matters. We have assumed a universe that contains superclusters. Superclusters arethen made of clusters. Each cluster can be further divided into smaller ones and so on. We havederived an expression for the entropy of such a universe. Our model is rather independent of thegeometry of

Shahid N. Afridi; Khalid Khan

2006-01-01

15

How Is the Ideal Gas Law Explanatory?  

ERIC Educational Resources Information Center

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…

Woody, Andrea I.

2013-01-01

16

Ideal gas matching for thermal Galilean holography  

SciTech Connect

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

Barbon, Jose L. F.; Fuertes, Carlos A. [Instituto de Fisica Teorica IFT UAM/CSIC, Facultad de Ciencias C-XVI, C.U. Cantoblanco, E-28049 Madrid (Spain)

2009-07-15

17

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

18

Ideal gas provides q-entropy  

NASA Astrophysics Data System (ADS)

A mathematical procedure is suggested to obtain deformed entropy formulas of type K(SK)=?PiK(-lnPi), by requiring zero mutual K(SK)-information between a finite subsystem and a finite reservoir. The use of this method is first demonstrated on the ideal gas equation of state with finite constant heat capacity, C, where it delivers the Rényi and Tsallis formulas. A novel interpretation of the q?=2-q duality arises from the comparison of canonical subsystem and total microcanonical partition approaches. In the sequel a new, generalized deformed entropy formula is constructed for the linear C(S)=C0+C1S relation.

Biró, T. S.

2013-08-01

19

Quantum Darwinism in non-ideal environments  

E-print Network

Quantum Darwinism provides an information-theoretic framework for the emergence of the objective, classical world from the quantum substrate. The key to this emergence is the proliferation of redundant information throughout the environment where observers can then intercept it. We study this process for a purely decohering interaction when the environment, E, is in a non-ideal (e.g., mixed) initial state. In the case of good decoherence, that is, after the pointer states have been unambiguously selected, the mutual information between the system, S, and an environment fragment, F, is given solely by F's entropy increase. This demonstrates that the environment's capacity for recording the state of S is directly related to its ability to increase its entropy. Environments that remain nearly invariant under the interaction with S, either because they have a large initial entropy or a misaligned initial state, therefore have a diminished ability to acquire information. To elucidate the concept of good decoherence, we show that - when decoherence is not complete - the deviation of the mutual information from F's entropy change is quantified by the quantum discord, i.e., the excess mutual information between S and F is information regarding the initial coherence between pointer states of S. In addition to illustrating these results with a single qubit system interacting with a multi-qubit environment, we find scaling relations for the redundancy of information acquired by the environment that display a universal behavior independent of the initial state of S. Our results demonstrate that Quantum Darwinism is robust with respect to non-ideal initial states of the environment: the environment almost always acquires redundant information about the system but its rate of acquisition can be reduced.

Michael Zwolak; H. T. Quan; Wojciech H. Zurek

2010-06-08

20

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

21

WINDING-INVARIANT PRIME IDEALS IN QUANTUM 3 3 MATRICES  

E-print Network

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

Lenagan, Tom

22

Thermodynamic functions of lactams in the ideal gas state  

NASA Astrophysics Data System (ADS)

Thermodynamic functions (enthalpy, entropy, free energy, and heat capacity) of azacycloalkan-2-ones with ring sizes n = 4-8 in the ideal gas state are calculated by means of quantum chemistry and statistical physics, using an anharmonic approximation in the range of 298-1500 K with allowance for all known conformers and optical isomers. Equilibrium structures and total energies of lactams are calculated using the B3LYP/6-311++G(3 df, 3 pd), B3LYP/aug-cc-pVQZ, and MP2/6-311++G(3 df, 3 pd) methods, and the anharmonic frequencies of the fundamental vibrations of all the investigated structures were found via B3LYP/6-311++G(3 df, 3 pd).

Emel'yanenko, V. N.; Turovtsev, V. V.; Orlov, Yu. D.

2014-09-01

23

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

24

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

25

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

26

Viscosity of an ideal relativistic quantum fluid: A perturbative study  

E-print Network

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

Giorgio Torrieri

2012-02-14

27

A Demonstration of Ideal Gas Principles Using a Football  

NASA Astrophysics Data System (ADS)

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

Bare, William D.; Andrews, Lester

1999-05-01

28

A Demonstration of Ideal Gas Principles Using a Football  

Microsoft Academic Search

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

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

1999-01-01

29

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

30

A two-dimensional ideal gas finite element  

Microsoft Academic Search

The formulation of a family of two-dimensional finite elements that model an ideal gas is presented. The elements support nonlinear analysis and represent either a plane strain or axisymmetric condition. The family of elements is intended for use with conventional elasticity-type elements to perform structural analysis of insulated glass units, pressure vessels, and other systems for which the interaction between

Richard J. Schmidt; Keith R. Fulton

2001-01-01

31

Thermal transport through non-ideal Andreev quantum dots  

E-print Network

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

Pedro Vidal

2015-01-07

32

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

33

Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas  

E-print Network

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 ...

Sanner, Christian Burkhard

34

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

NASA Astrophysics Data System (ADS)

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 ?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, Xiu-Ming; Tian, Chi

2015-01-01

35

Microeconomics of the ideal gas like market models  

NASA Astrophysics Data System (ADS)

We develop a framework based on microeconomic theory from which the ideal gas like market models can be addressed. A kinetic exchange model based on that framework is proposed and its distributional features have been studied by considering its moments. Next, we derive the moments of the CC model (Eur. Phys. J. B 17 (2000) 167) as well. Some precise solutions are obtained which conform with the solutions obtained earlier. Finally, an output market is introduced with global price determination in the model with some necessary modifications.

Chakrabarti, Anindya S.; Chakrabarti, Bikas K.

2009-10-01

36

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

37

Why Quantum Bit Commitment And Ideal Quantum Coin Tossing Are Impossible  

E-print Network

There had been well known claims of unconditionally secure quantum protocols for bit commitment. However, we, and independently Mayers, showed that all proposed quantum bit commitment schemes are, in principle, insecure because the sender, Alice, can almost always cheat successfully by using an Einstein-Podolsky-Rosen (EPR) type of attack and delaying her measurements. One might wonder if secure quantum bit commitment protocols exist at all. We answer this question by showing that the same type of attack by Alice will, in principle, break any bit commitment scheme. The cheating strategy generally requires a quantum computer. We emphasize the generality of this ``no-go theorem'': Unconditionally secure bit commitment schemes based on quantum mechanics---fully quantum, classical or quantum but with measurements---are all ruled out by this result. Since bit commitment is a useful primitive for building up more sophisticated protocols such as zero-knowledge proofs, our results cast very serious doubt on the security of quantum cryptography in the so-called ``post-cold-war'' applications. We also show that ideal quantum coin tossing is impossible because of the EPR attack. This no-go theorem for ideal quantum coin tossing may help to shed some lights on the possibility of non-ideal protocols.

H. -K. Lo; H. F. Chau

1997-11-26

38

Why quantum bit commitment and ideal quantum coin tossing are impossible  

NASA Astrophysics Data System (ADS)

There had been well-known claims of unconditionally secure quantum protocols for bit commitment. However, we, and independently Mayers, showed that all proposed quantum bit commitment schemes are, in principle, insecure because the sender, Alice, can almost always cheat successfully by using an Einstein-Podolsky-Rosen (EPR) type of attack and delaying her measurements. One might wonder if secure quantum bit commitment protocols exist at all. We answer this question by showing that the same type of attack by Alice will, in principle, break any bit commitment scheme. The cheating strategy generally requires a quantum computer. We emphasize the generality of this “no-go theorem”: Unconditionally secure bit commitment schemes based on quantum mechanics-fully quantum, classical or quantum but with measurements-are all ruled out by this result. Since bit commitment is a useful primitive for building up more sophisticated protocols such as zero-knowledge proofs, our results cast very serious doubt on the security of quantum cryptography in the so-called “post-cold-war” applications. We also show that ideal quantum coin tossing is impossible because of the EPR attack. This no-go theorem for ideal quantum coin tossing may help to shed some lights on the possibility of non-ideal protocols.

Lo, Hoi-Kwong; Chau, H. F.

1998-09-01

39

FAST TRACK COMMUNICATION: Stochastic field equation for the canonical ensemble of an ideal Bose gas  

NASA Astrophysics Data System (ADS)

We present a novel norm preserving stochastic evolution equation for a Bose field at finite temperature. Ensemble averages are quantum expectation values in the canonical ensemble. This numerically very stable equation suppresses high-energy fluctuations exponentially, which prevent cutoff problems from occurring. We present 3D simulations for an ideal gas in various trapping potentials and focus on ground-state occupation numbers and spatial correlation functions for a wide range of temperatures above and below the critical temperature. Although rigorously valid for non-interacting bosons only, we argue that weakly interacting Bose gases may also be amenable to this approach, in the usual mean-field approximation.

Heller, Sigmund; Strunz, Walter T.

2009-04-01

40

Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas  

SciTech Connect

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 [MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, and Department of Physics, Massachusetts Institute of Technology, Cambridge Massachusetts 02139 (United States)

2010-07-23

41

Why quantum bit commitment and ideal quantum coin tossing are impossible  

E-print Network

There had been well known claims of ``provably unbreakable'' quantum protocols for bit commitment and coin tossing. However, we, and independently Mayers, showed that all proposed quantum bit commitment (and therefore coin tossing) schemes are, in principle, insecure because the sender, Alice, can always cheat successfully by using an EPR-type of attack and delaying her measurements. One might wonder if secure quantum bit commitment and coin tossing protocols exist at all. Here we prove that an EPR-type of attack by Alice will, in principle, break {\\em any} realistic quantum bit commitment and {\\em ideal} coin tossing scheme. Therefore, provided that Alice has a quantum computer and is capable of storing quantum signals for an arbitrary length of time, all those schemes are insecure. Since bit commitment and coin tossing are useful primitives for building up more sophisticated protocols such as zero-knowledge proofs, our results cast very serious doubt on the security of quantum cryptography in the so-called ``post-cold-war'' applications.

Hoi-Kwong Lo; H. F. Chau

1996-05-16

42

Effect of spin-orbit interaction on the critical temperature of an ideal Bose gas  

NASA Astrophysics Data System (ADS)

We consider Bose-Einstein condensation of an ideal Bose gas with an equal mixture of `Rashba' and `Dresselhaus' spin-orbit interactions and study its effect on the critical temperature. In uniform Bose gas a `cusp' and a sharp drop in the critical temperature occurs due to the change in the density of states at a critical Raman coupling where the degeneracy of the ground states is lifted. Relative drop in the critical temperature depends on the diluteness of the gas as well as on the spin-orbit coupling strength. In the presence of a harmonic trap, the cusp in the critical temperature is smoothened out and a minimum in the critical temperature appears. Both the drop in the critical temperature and lifting of `quasi-degeneracy' of the ground states exhibit crossover phenomena and disappears for sufficiently strong trap frequency. By considering a `Dicke'-like model we extend our calculation to bosons with large spin and observe a similar minimum in the critical temperature near the critical Raman frequency, which becomes deeper for larger spin. Finally in the limit of infinite spin, the critical temperature vanishes at the critical frequency, which is a manifestation of Dicke type quantum phase transition.

Roy, Arunesh; Ray, Sayak; Sinha, Subhasis

2014-12-01

43

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

E-print Network

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

44

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

45

Real-gas effects 1: Simulation of ideal gas flow by cryogenic nitrogen and other selected gases  

NASA Technical Reports Server (NTRS)

The thermodynamic properties of nitrogen gas do not thermodynamically approximate an ideal, diatomic gas at cryogenic temperatures. Choice of a suitable equation of state to model its behavior is discussed and the equation of Beattie and Bridgeman is selected as best meeting the needs for cryogenic wind tunnel use. The real gas behavior of nitrogen gas is compared to an ideal, diatomic gas for the following flow processes: isentropic expansion; normal shocks; boundary layers; and shock wave boundary layer interactions. The only differences in predicted pressure ratio between nitrogen and an ideal gas that may limit the minimum operating temperatures of transonic cryogenic wind tunnels seem to occur at total pressures approaching 9atmospheres and total temperatures 10 K below the corresponding saturation temperature, where the differences approach 1 percent for both isentropic expansions and normal shocks. Several alternative cryogenic test gases - air, helium, and hydrogen - are also analyzed. Differences in air from an ideal, diatomic gas are similar in magnitude to those of nitrogen. Differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. Helium and hydrogen do not approximate the compressible flow of an ideal, diatomic gas.

Hall, R. M.

1980-01-01

46

Application of quantum cascade lasers to trace gas analysis  

Microsoft Academic Search

Quantum cascade (QC) lasers are virtually ideal mid-infrared sources for trace gas monitoring. They can be fabricated to operate\\u000a at any of a very wide range of wavelengths from ??3 ?m to ??24 ?m. Seizing the opportunity presented by mid-infrared QC lasers,\\u000a several groups world-wide are actively applying them to trace gas sensing. Real world applications include environmental monitoring,\\u000a industrial process control

A. Kosterev; G. Wysocki; Y. Bakhirkin; S. So; R. Lewicki; M. Fraser; F. Tittel; R. F. Curl

2008-01-01

47

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

48

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

49

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.

50

Cooking under Pressure: Applying the Ideal Gas Law in the Kitchen  

ERIC Educational Resources Information Center

This case study uses a daily cooking scenario to demonstrate how the boiling point of water is directly related to the external pressures in order to reinforce the concepts of boiling and boiling point, apply ideal gas law, and relate chemical reaction rates with temperatures. It also extends its teaching to autoclaves used to destroy…

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

2010-01-01

51

A note on the zero point energy of an ideal boson gas  

Microsoft Academic Search

We have recently demonstrated that, when investigating the internal energy and pressure of an ideal boson gas at temperatures below the Bose-Einstein temperature, it is necessary to include the contribution from the kinetic energy of the particles in the condensate. Here we express the same requirement in terms of the constraints of the Heisenberg uncertainty principle applied to the particles

F. A. Deeney; J. P. O'Leary

2011-01-01

52

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

Microsoft Academic Search

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

C. G. Speziale

1986-01-01

53

GasKinetic Theory Based Flux Splitting Method for Ideal Magnetohydrodynamics  

E-print Network

to the MHD equations has not been fully addressed. The search for robust, accurate and efficient MHD flow Abstract A gas­kinetic flux splitting method is developed for the ideal magnetohydrodynamics (MHD) equa­ tions. The new scheme is based on the direct splitting of the flux function of the MHD equations

Xu, Kun

54

How Incorrect Is the Classical Partition Function for the Ideal Gas?  

ERIC Educational Resources Information Center

Discussed is the classical partition function for the ideal gas and how it differs from the exact value for bosons or fermions in the classical regime. The differences in the two values are negligible hence the classical treatment leads in the end to correct answers for all observables. (Author/DS)

Kroemer, Herbert

1980-01-01

55

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

56

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

57

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

E-print Network

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

Boal, David

58

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

59

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

60

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

61

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

Microsoft Academic Search

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

Vitaly V. Kocharovsky; Vladimir V. Kocharovsky

2010-01-01

62

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

63

Why Quantum Bit Commitment And Ideal Quantum Coin Tossing Are Impossible  

E-print Network

There had been well known claims of unconditionally secure quantum protocols for bit commitment. However, we, and independently Mayers, showed that all proposed quantum bit commitment schemes are, in principle, insecure because the sender, Alice, can almost always cheat successfully by using an Einstein-Podolsky-Rosen (EPR) type of attack and delaying her measurements. One might wonder if secure quantum bit commitment protocols exist at all. We answer this question by showing that the same type of attack by Alice will, in principle, break any bit commitment scheme. The cheating strategy generally requires a quantum computer. We emphasize the generality of this ``no-go theorem'': Unconditionally secure bit commitment schemes based on quantum mechanics---fully quantum, classical or quantum but with measurements---are all ruled out by this result. Since bit commitment is a useful primitive for building up more sophisticated protocols such as zero-knowledge proofs, our results cast very serious doubt on the secur...

Lo, H K

1998-01-01

64

Two-level trap model of BEC in an ideal gas  

NASA Astrophysics Data System (ADS)

We consider a two-energy-level trap with arbitrary degeneracy of an upper level and find an analytical solution for the condensate statistics in a mesoscopic ideal gas with arbitrary number of atoms and any temperature, including a critical region. The solution is a cut-off negative binomial distribution that tends to a cut-off gamma distribution in the thermodynamic limit. We show how to model BEC in real traps by BEC in the two-level or three-level traps.

Dorfman, Konstantin; Kocharovsky, Vitaly; Kocharovsky, Vladimir

2009-04-01

65

Probability theory for 3-layer remote sensing in ideal gas law environment.  

PubMed

We extend the probability model for 3-layer radiative transfer [Opt. Express 20, 10004 (2012)] to ideal gas conditions where a correlation exists between transmission and temperature of each of the 3 layers. The effect on the probability density function for the at-sensor radiances is surprisingly small, and thus the added complexity of addressing the correlation can be avoided. The small overall effect is due to (a) small perturbations by the correlation on variance population parameters and (b) cancellation of perturbation terms that appear with opposite signs in the model moment expressions. PMID:24105525

Ben-David, Avishai; Davidson, Charles E

2013-08-26

66

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

SciTech Connect

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

2013-05-15

67

Ideal Negative Measurements in Quantum Walks Disprove Theories Based on Classical Trajectories  

NASA Astrophysics Data System (ADS)

We report on a stringent test of the nonclassicality of the motion of a massive quantum particle, which propagates on a discrete lattice. Measuring temporal correlations of the position of single atoms performing a quantum walk, we observe a 6 ? violation of the Leggett-Garg inequality. Our results rigorously excludes (i.e., falsifies) any explanation of quantum transport based on classical, well-defined trajectories. We use so-called ideal negative measurements—an essential requisite for any genuine Leggett-Garg test—to acquire information about the atom's position, yet avoiding any direct interaction with it. The interaction-free measurement is based on a novel atom transport system, which allows us to directly probe the absence rather than the presence of atoms at a chosen lattice site. Beyond the fundamental aspect of this test, we demonstrate the application of the Leggett-Garg correlation function as a witness of quantum superposition. Here, we employ the witness to discriminate different types of walks spanning from merely classical to wholly quantum dynamics.

Robens, Carsten; Alt, Wolfgang; Meschede, Dieter; Emary, Clive; Alberti, Andrea

2015-01-01

68

Why quantum bit commitment and ideal quantum coin tossing are impossible  

Microsoft Academic Search

There had been well-known claims of unconditionally secure quantum protocols for bit commitment. However, we, and independently Mayers, showed that all proposed quantum bit commitment schemes are, in principle, insecure because the sender, Alice, can almost always cheat successfully by using an Einstein-Podolsky-Rosen (EPR) type of attack and delaying her measurements. One might wonder if secure quantum bit commitment protocols

Hoi-Kwong Lo; H. F. Chau

1998-01-01

69

Why quantum bit commitment and ideal quantum coin tossing are impossible  

Microsoft Academic Search

There had been well known claims of ``provably unbreakable'' quantum protocols for bit commitment and coin tossing. However, we, and independently Mayers, showed that all proposed quantum bit commitment (and therefore coin tossing) schemes are, in principle, insecure because the sender, Alice, can always cheat successfully by using an EPR-type of attack and delaying her measurements. One might wonder if

Hoi-Kwong Lo; H. F. Chau

1996-01-01

70

Quantum chaos theory and the spectrum of ideal-MHD instabilities in toroidal plasmas  

E-print Network

In a fully 3-D system such as a stellarator, the toroidal mode number $n$ ceases to be a good quantum number--all $n$s within a given mode family being coupled. It is found that the discrete spectrum of unstable ideal MHD (magnetohydrodynamic) instabilities ceases to exist unless MHD is modified (regularized) by introducing a short-perpendicular-wavelength cutoff. Attempts to use ray tracing to estimate the regularized MHD spectrum fail due to the occurrence of chaotic ray trajectories. In quantum chaos theory, strong chaos in the semiclassical limit leads to eigenvalue statistics the same as those of a suitable ensemble of random matrices. For instance, the probability distribution function for the separation between neighboring eigenvalues is as derived from random matrix theory and goes to zero at zero separation. This contrasts with the Poissonian distribution found in separable systems, showing that a signature of quantum chaos is level repulsion. In order to determine whether eigenvalues of the regularized MHD problem obey the same statistics as those of the Schr\\"odinger equation in both the separable 1-D case and the chaotic 3-D cases, we have assembled data sets of ideal MHD eigenvalues for a Suydam-unstable cylindrical (1-D) equilibrium using \\emph{Mathematica} and a Mercier-unstable (3-D) equilibrium using the CAS3D code. In the 1-D case, we find that the unregularized Suydam-approximation spectrum has an anomalous peak at zero eigenvalue separation. On the other hand, regularization by restricting the domain of $\\kvec_{\\perp}$ recovers the expected Poissonian distribution. In the 3-D case we find strong evidence of level repulsion within mode families, but mixing mode families produces Poissonian statistics.

R. L. Dewar; C. Nuehrenberg; T. Tatsuno

2004-09-15

71

Redundant imprinting of information in non-ideal environments: Quantum Darwinism via a noisy channel  

NASA Astrophysics Data System (ADS)

Quantum Darwinism provides an information-theoretic framework for the emergence of the classical world from the quantum substrate. It recognizes that we - the observers - acquire our information about the "systems of interest" indirectly from their imprints on the environment. Objectivity, a key property of the classical world, arises via the proliferation of redundant information into the environment where many observers can then intercept it and independently determine the state of the system. While causing a system to decohere, environments that remain nearly invariant under the Hamiltonian dynamics, such as very mixed states, have a diminished ability to transmit information about the system, yet can still acquire redundant information about the system [1,2]. Our results show that Quantum Darwinism is robust with respect to non-ideal initial states of the environment.[4pt] [1] M. Z., H. T. Q., W. H. Z., Phys. Rev. Lett. 103, 110402 (2009)[0pt] [2] M. Z., H. T. Q., W. H. Z., Phys. Rev. A 81, 062110 (2010)

Zwolak, Michael; Quan, Haitao; Zurek, Wojciech

2011-03-01

72

Relaxation of excited spin, orbital, and valley qubit states in ideal silicon quantum dots  

NASA Astrophysics Data System (ADS)

We review and expand on previous work that treats relaxation physics of low-lying excited states in ideal, single-electron, silicon quantum dots in the context of quantum computing. These states are of three types: orbital, valley, and spin. The relaxation times depend sensitively on system parameters such as the dot size and the external magnetic field. Generally, however, orbital relaxation times are short in strained silicon (10-7 to 10-12 s), spin-relaxation times are long (10-6 to ?1 s), while valley relaxation times are expected to lie in between. The focus is on relaxation due to emission or absorption of phonons, but for spin relaxation we also consider competing mechanisms such as charge noise. Where appropriate, comparison is made to reference systems such as quantum dots in III-V materials and silicon donor states. The phonon-bottleneck effect is shown to be rather small in the regime of interest. We compare the theoretical predictions to some recent spin relaxation experiments and comment on the possible effects of nonideal dots.

Tahan, Charles; Joynt, Robert

2014-02-01

73

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

NASA Astrophysics Data System (ADS)

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.; Kocharovsky, Vladimir V.

2010-03-01

74

Quantum noise properties of non-ideal optical amplifiers and attenuators This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-print Network

Quantum noise properties of non-ideal optical amplifiers and attenuators This article has been properties of non-ideal optical amplifiers and attenuators Zhimin Shi1 , Ksenia Dolgaleva1,2 and Robert W 26 1817) of the noise properties of ideal linear amplifiers to include the possibility of non

Boyd, Robert W.

75

Global weak solutions to the NavierStokes equations for a 1D viscous polytropic ideal gas  

E-print Network

\\Gamma and v \\Sigma = 0 are assumed. In [8] global generalized solutions to the Cauchy problemGlobal weak solutions to the Navier­Stokes equations for a 1D viscous polytropic ideal gas Song 100080, China E­Mail: zp@math03.math.ac.cn Abstract We prove the existence of global weak solutions

76

Student understanding of the first law of thermodynamics: Relating work to the adiabatic compression of an ideal gas  

Microsoft Academic Search

We report on an investigation of student understanding of the first law of thermodynamics. The students involved were drawn from first-year university physics courses and a second-year thermal physics course. The emphasis was on the ability of the students to relate the first law to the adiabatic compression of an ideal gas. Although they had studied the first law, few

Michael E. Loverude; Christian H. Kautz; Paula R. L. Heron

2002-01-01

77

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

ERIC Educational Resources Information Center

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

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

2012-01-01

78

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

79

Quantum Algorithms for many-to-one Functions to Solve the Regulator and the Principal Ideal Problem  

E-print Network

We propose new quantum algorithms to solve the regulator and the principal ideal problem in a real-quadratic number field. We improve the algorithms proposed by Hallgren by using two different techniques. The first improvement is the usage of a period function which is not one-to-one on its period. We show that even in this case Shor's algorithm computes the period with constant probability. The second improvement is the usage of reduced forms (a, b, c) of discriminant D with a>0 instead of reduced ideals of the same discriminant. These improvements reduce the number of required qubits by at least 2 log D.

Arthur Schmidt

2009-12-24

80

Theoretical analysis of the formulation of the principle of superposition of laser excitation and collisional relaxation of oscillations of ideal gas molecules. II  

Microsoft Academic Search

The principles underlying the microscopic theory of relaxation of the vibrational energy of ideal gas molecules in the field of resonant laser emission are examined. The analysis demonstrates the ill posedness of the accepted statement of the principle of superposition of photon absorption (emission) and collisional relaxation of the oscillations of ideal gas molecules. The same conclusion applies to the

T. Z. Kalanov

1990-01-01

81

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

82

History dependent quantum random walks as quantum lattice gas automata  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

83

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

84

Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles  

E-print Network

We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, composite sound waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition between the hydrodynamical regime of an ideal gas, defined in this work, and the hydrodynamical regime in phenomenological hydrodynamics, which is normally used for the description of interacting gases.

Sašo Grozdanov; Janos Polonyi

2015-01-26

85

On the Equipartition of Kinetic Energy in an Ideal Gas Mixture  

ERIC Educational Resources Information Center

A refinement of an argument due to Maxwell for the equipartition of translational kinetic energy in a mixture of ideal gases with different masses is proposed. The argument is elementary, yet it may work as an illustration of the role of symmetry and independence postulates in kinetic theory. (Contains 1 figure.)

Peliti, L.

2007-01-01

86

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

87

Direct Biexciton Creation with Two-Photon Excitation for Ideal Entangled Photon Pair Emissions in Optically Active Quantum Dots  

NASA Astrophysics Data System (ADS)

A scheme for creating biexcitons without undesirable excitons is demonstrated in GaAs quantum dots (QDs) using an optical pumping method. This scheme utilizes resonant two-photon excitation processes for biexcitons with carefully set excitation conditions. In this scheme, biexcitons are directly created from the ground state while suppressing unnecessary exciton creation. Theoretical analysis confirms that our scheme works in actual QDs. Directly created biexcitons will make ideal entangled photons via cascade photoemission processes in a biexciton-exciton system with the reduction in the number of undesirable single photons from excitons that are not related to the cascade processes.

Gotoh, Hideki; Sanada, Haruki; Yamaguchi, Hiroshi; Sogawa, Tetsuomi

2013-12-01

88

Ideal-Gas Heat Capacity Values and Equations for Hydrofluorocarbon (HFC) Refrigerants Based on Speed-of-Sound Measurements  

Microsoft Academic Search

Final values of ideal-gas heat capacity c0p derived from speed-of-sound measurements using an acoustic spherical resonator and equations of c0p as a simple function of temperature are provided from an overall assessment of speed-of-sound measurements for five hydrofluorocarbon (HFC) refrigerants, difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), and 1,1-difluoroethane (R152a). Some of the experimental results had systematic errors in

H. Sato; T. Kojima; K. Ogawa

2002-01-01

89

Plane one-dimensional stationary flow of an ideal charged gas in its own electric field  

Microsoft Academic Search

The plane one-dimensional flow of an incompressible gas consisting of a neutral and a charged component in its own electric field has been investigated by Stuetzer [1]. Stuetzer's results are valid when the electrostatic pressure is small compared with the hydraulic pressure. In the present paper an analogous problem is considered for a compressible gas under the more general assumption

Yu. A. Nagel

1971-01-01

90

Self-similar analytical solution of the critical fluctuations problem for the Bose-Einstein condensation in an ideal gas  

NASA Astrophysics Data System (ADS)

An exact analytical solution for the universal probability distribution of the order parameter fluctuations as well as for the universal statistical and thermodynamic functions of an ideal gas in the whole critical region of Bose-Einstein condensation (BEC) is obtained. A universal constraint nonlinearity is found that is responsible for all nontrivial critical phenomena of the BEC phase transition. Simple analytical approximations, which describe the universal structure of the critical region in terms of confluent hypergeometric or parabolic cylinder functions, as well as asymptotics of the exact solution are derived. The results for the order parameter, all higher order moments of BEC fluctuations and thermodynamic quantities, including specific heat, perfectly match the known asymptotics outside critical region as well as the phenomenological renormalization-group ansatz with known critical exponents in the close vicinity of the critical point. Thus, a full analytical solution to a long-standing problem of finding a universal structure of the ? point for BEC in an ideal gas is found.

Kocharovsky, Vitaly V.; Kocharovsky, Vladimir V.

2010-06-01

91

Student understanding of the first law of thermodynamics: Relating work to the adiabatic compression of an ideal gas  

NSDL National Science Digital Library

We report on an investigation of student understanding of the first law of thermodynamics. The students involved were drawn from first-year university physics courses and a second-year thermal physics course. The emphasis was on the ability of the students to relate the first law to the adiabatic compression of an ideal gas. Although they had studied the first law, few students recognized its relevance. Fewer still were able to apply the concept of work to account for a change in temperature in an adiabatic process. Instead most of the students based their predictions and explanations on a misinterpretation of the ideal gas law. Even when ideas of energy and work were suggested, many students were unable to give a correct analysis. They frequently failed to differentiate the concepts of heat, temperature, work, and internal energy. Some of the difficulties that students had in applying the concept of work in a thermal process seemed to be related to difficulties with mechanics. Our findings also suggest that a misinterpretation of simple microscopic models may interfere with student ability to understand macroscopic phenomena. Implications for instruction in thermal physics and in mechanics are discussed.

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

2005-10-27

92

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

E-print Network

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

Winokur, Michael

93

Confinement effects and deviations from ideality of vapours at the adsorbed phase\\/gas interface  

Microsoft Academic Search

In the present work, confinement effects are evidenced both from the side of the adsorbed phase as well as from the gas phase of the same fluid. A generalization of these confinement effects is proposed by using the corresponding states principle as a classical tool to compare adsorption phenomena. The lowest closure point of hysteresis loop has been chosen because

Stéphane Pariente; Pierre Marie Papineschi; Philippe Trens

2007-01-01

94

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

95

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

E-print Network

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

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

2014-12-02

96

A single impurity in an ideal atomic Fermi gas: current understanding and some open problems  

E-print Network

We briefly review some current theoretical and experimental aspects of the problem of a single spinless impurity in a 3D polarised atomic Fermi gas at zero temperature where the interactions can be tuned using a wide Feshbach resonance. We show that various few-body states in vacuum composed of the impurity and background gas atoms (single impurity, dimer, trimer, tetramer) give rise to corresponding dressed states ({\\em polaron}, {\\em dimeron}, {\\em trimeron}, {\\em tetrameron}) in the gas and inherit many of their characteristics. We study the ground state focussing on the choice of wave function and its properties. We raise a few unsolved problems: whether the polaron and dimeron are really separate branches, what other few-body states might exist, the nature of the groundstate for large numbers of particle-hole pairs and why is the polaron ansatz so good. We then turn to the excited states, and to the calculation of the effective mass. We examine the bounds on the effective mass and raise a conjecture about that of composite quasiparticle states.

Zhihao Lan; Carlos Lobo

2014-04-11

97

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

98

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

99

Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles  

E-print Network

We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, composite sound waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition betwee...

Grozdanov, Sašo

2015-01-01

100

Steady Secondary Flows Generated by Periodic Compression and Expansion of an Ideal Gas in a Pulse Tube  

NASA Technical Reports Server (NTRS)

This study establishes a consistent set of differential equations for use in describing the steady secondary flows generated by periodic compression and expansion of an ideal gas in pulse tubes. Also considered is heat transfer between the gas and the tube wall of finite thickness. A small-amplitude series expansion solution in the inverse Strouhal number is proposed for the two-dimensional axisymmetric mass, momentum and energy equations. The anelastic approach applies when shock and acoustic energies are small compared with the energy needed to compress and expand the gas. An analytic solution to the ordered series is obtained in the strong temperature limit where the zeroth-order temperature is constant. The solution shows steady velocities increase linearly for small Valensi number and can be of order I for large Valensi number. A conversion of steady work flow to heat flow occurs whenever temperature, velocity or phase angle gradients are present. Steady enthalpy flow is reduced by heat transfer and is scaled by the Prandtl times Valensi numbers. Particle velocities from a smoke-wire experiment were compared with predictions for the basic and orifice pulse tube configurations. The theory accurately predicted the observed steady streaming.

Lee, Jeffrey M.

1999-01-01

101

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

102

Jack polynomials as fractional quantum Hall states and the Betti numbers of the (k+1)-equals ideal  

E-print Network

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

Christine Berkesch Zamaere; Stephen Griffeth; Steven V Sam

2014-04-23

103

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

SciTech Connect

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, E-mail: mbeau@stp.dias.ie [Dublin Institute for Advanced Studies School of Theoretical Physics, 10 Burlington Road, Dublin 4 (Ireland)] [Dublin Institute for Advanced Studies School of Theoretical Physics, 10 Burlington Road, Dublin 4 (Ireland); Savoie, Baptiste, E-mail: baptiste.savoie@gmail.com [Department of Mathematical Sciences, University of Aarhus, Ny Munkegade, Building 1530, DK-8000 Aarhus C (Denmark)] [Department of Mathematical Sciences, University of Aarhus, Ny Munkegade, Building 1530, DK-8000 Aarhus C (Denmark)

2014-05-15

104

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

105

Acoustic determination of ideal-gas heat capacity and second virial coefficients of some refrigerants between 250 and 420 K  

NASA Astrophysics Data System (ADS)

An apparatus for speed-of-sound measurements with a spherical resonator was adapted for temperatures up to 42(I K. This included new microphones with a special wiring, a pressure indicator which can be thermostatted to 420 K, and some installations to avoid temperature gradients. Calibration of the radius of the resonator with argon was extended to higher temperatures. Speed-of-sound measurements up to 420 K and 0.5 MPa were done onl,l-dilluoroethane (R152a). 1.l,l-trilluoroethane (R 143a ),l,l,l-chlorodifluoroethane (R 142b ), l,1,1,2-tetralluoroethane (R134a), and 2.2.2-trifluoroethanol. The ideal-gas heat capacities coincide with the statistical mechanical values, except for R134a, where our values as well as recent literature data are below the values calculated from spectroscopy. The reduced second virial coefficients can be interpreted in terms of the dipole moment and the angle between dipole moment and molecular axis. For the associated substance trifluoroethanol values of the third virial coefficient are given, which are appreciably negative at low temperatures.

Beekermann, W.; Kohler, F.

1995-03-01

106

Test of dilute gas approximation in quantum mechanical model  

Microsoft Academic Search

The validity of dilute gas approximation is explored by making use of the large-sized instanton in quantum mechanical model. It is shown that the Euclidean probability amplitude derived through a dilute gas approximation not only cannot explain the result of the linear combination of atomic orbitals approximation, but also does not exhibit a proper limiting case when the size of

D. K. Park; Soo-Young Lee; Jae-Rok Kahng; Sahng-Kyoon Yoo; C. H. Lee; Chang Soo Park; Eui-Soon Yim

1996-01-01

107

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

108

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

109

Quantum control of molecular gas hydrodynamics.  

PubMed

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. PMID:24765959

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

2014-04-11

110

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

111

An accurate, residue-level, pair potential of mean force for folding and binding based on the distance-scaled, ideal-gas reference state  

Microsoft Academic Search

Structure prediction on a genomic scale requires a simplified energy function that can efficiently sample the conformational space of polypeptide chains. A good energy function at minimum should discriminate native structures against decoys. Here, we show that a recently developed, residue-specific, all-atom knowledge- based potential (167 atomic types) based on distance-scaled, finite ideal-gas reference state (DFIRE-all- atom) can be substantially

CHI ZHANG; SONG LIU; HONGYI ZHOU; YAOQI ZHOU

2004-01-01

112

Quantum Master Equation of a Particle in a Gas Environment  

Microsoft Academic Search

The evolution of the reduced density operator $\\\\rho$ of 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 {\\\\it local} environmental interactions. We derive a Lindblad master equation for $\\\\rho$, whose generators are calculated from differential cross section of a single collision between

L. Diósi

1995-01-01

113

Tunnel-field-effect-transistor based gas-sensor: Introducing gas detection with a quantum-mechanical transducer  

E-print Network

Tunnel-field-effect-transistor based gas-sensor: Introducing gas detection with a quantum; published online 17 January 2013) A gas-sensor based on tunnel-field-effect-transistor (TFET) is proposed that leverages the unique current injection mechanism in the form of quantum-mechanical band-to-band tunneling

114

Two-dimensional quantum gas in a hybrid surface trap  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

115

Manipulation of Ideals 1 Radical ideals  

E-print Network

Manipulation of Ideals 1 Radical ideals the radical ideal membership problem 2 Independence Computation (MCS 563) Manipulation of Ideals L-33 7 April 2014 1 / 30 #12;Manipulation of Ideals 1 Radical) Manipulation of Ideals L-33 7 April 2014 2 / 30 #12;polynomial ideals An ideal I generated by N polynomials fi

Verschelde, Jan

116

Stability of a trapped dipolar quantum gas  

NASA Astrophysics Data System (ADS)

We calculate the stability diagram for a trapped normal Fermi or Bose gas with dipole-dipole interactions. Our study characterizes the roles of trap geometry and temperature on the stability using Hartree-Fock theory. We find that exchange appreciably reduces stability and that, for bosons, the double instability feature in oblate trapping geometries predicted previously is still predicted by the Hartree-Fock theory. Our results are relevant to current experiments with polar molecules and will be useful in developing strategies to obtain a polar molecule Bose-Einstein condensate or degenerate Fermi gas.

Baillie, D.; Bisset, R. N.; Blakie, P. B.

2015-01-01

117

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

118

Quantum Master Equation of Particle in Gas Environment  

E-print Network

The evolution of the reduced density operator $\\rho$ of 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 {\\it local} environmental interactions. We derive a Lindblad master equation for $\\rho$, whose generators are calculated from differential cross section of a single collision between Brownian and gas particles, respectively. The existence of thermal equilibrium for $\\rho$ is proved. Master equations proposed earlier are shown to be particular cases of our one.

Lajos Diosi

1994-03-23

119

Multicomponent gas analysis using broadband quantum cascade laser spectroscopy.  

PubMed

We present a broadband quantum cascade laser-based spectroscopic system covering the region between 850 and 1250 cm(-1). Its robust multipass cavity ensures a constant interaction length over the entire spectral region. The device enables the detection and identification of numerous molecules present in a complex gas mixture without any pre-treatment in two minutes. We demonstrate that we can detect sub-ppmv concentration of acetone in presence of 2% of water at the same wavenumber region. PMID:25089450

Reyes-Reyes, A; Hou, Z; van Mastrigt, E; Horsten, R C; de Jongste, J C; Pijnenburg, M W; Urbach, H P; Bhattacharya, N

2014-07-28

120

On the quantum field theory of the inhomogeneous electron gas  

Microsoft Academic Search

The equilibrium properties of an inhomogeneous gas of interacting fermions are derived using methods of finite temperature quantum field theory. A Landau-type quasiparticle spectrum yielding the exact ground state energy or, at finite temperatures, the exact thermodynamic potential is constructed from the g-Hartree equations. The heat kernel expansion of Schrödinger operators is then used to express the Hohenberg-Kohn density functional

K. Dietz; G. Weymans

1985-01-01

121

The spin Hall effect in a quantum gas.  

PubMed

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

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

2013-06-13

122

Quantum scalar-metric cosmology with Chaplygin gas  

NASA Astrophysics Data System (ADS)

A spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with generalized Chaplygin gas is studied in the context of scalar-metric formulation of cosmology. Schutz's mechanism for the perfect fluid is applied with generalized Chaplygin gas and the classical and quantum dynamics for this model is studied. It is found that the only surviving matter degree of freedom played the role of cosmic time. For the quantum mechanical description it is possible to find the wave packet which resulted from the linear superposition of the wave functions of the Schrödinger-Wheeler-DeWitt (SWD) equation, which is a consequence of the above formalism. The wave packets show two distinct dominant peaks and propagate in the direction of increasing scale factor. It may happen that our present universe originated from one of those peaks. The many-world and ontological interpretation of quantum mechanics is applied to investigate about the behavior of the scale factor and the scalar field (considered for this model). In both the cases the scale factor avoids singularity and a bouncing non-singular universe is found.

Majumder, Barun

2011-02-01

123

Control of hot-carrier relaxation for realizing ideal quantum-dot intermediate-band solar cells.  

PubMed

For intermediate-band solar cells, the broad absorption spectrum of quantum dots (QDs) offers a favorable conversion efficiency, and photocurrent generation via efficient two-step two-photon-absorption (TS-TPA) in QDs is essential for realizing high-performance solar cells. In the last decade, many works were dedicated to improve the TS-TPA efficiency by modifying the QD itself, however, the obtained results are far from the requirements for practical applications. To reveal the mechanisms behind the low TS-TPA efficiency in QDs, we report here on two- and three-beam photocurrent measurements of InAs quantum structures embedded in AlGaAs. Comparison of two- and three-beam photocurrent spectra obtained by subbandgap excitation reveals that the QD TS-TPA efficiency is improved significantly by suppressing the relaxation of hot TS-TPA carriers to unoccupied shallow InAs quantum structure states. PMID:24535195

Tex, David M; Kamiya, Itaru; Kanemitsu, Yoshihiko

2014-01-01

124

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

125

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

126

A Method to Simulate Linear Stability of Impulsively Accelerated Density Interfaces in Ideal-MHD and Gas Dynamics  

SciTech Connect

We present a numerical method to solve the linear stability of impulsively accelerated density interfaces in two dimensions such as those arising in the Richtmyer-Meshkov instability. The method uses an Eulerian approach, and is based on an unwind method to compute the temporally evolving base state and a flux vector splitting method for the perturbations. The method is applicable to either gas dynamics or magnetohydrodynamics. Numerical examples are presented for cases in which a hydrodynamic shock interacts with a single or double density interface, and a doubly shocked single density interface. Convergence tests show that the method is spatially second order accurate for smooth flows, and between first and second order accurate for flows with shocks.

Ravi Samtaney

2009-02-10

127

Indium phthalocyanine-CdSe/ZnS quantum dots nanocomposites showing size dependent and near ideal optical limiting behaviour  

NASA Astrophysics Data System (ADS)

Indium phthalocyanine-CdSe/ZnS quantum dots (QDs) nanocomposites (InPc-CdSe/ZnS) of three sizes (5.57, 8.12 and 8.75 nm) were synthesized according to known procedures. The particle size of the CdSe/ZnS QDs alone are 3.95, 6.02, and 6.66 nm, and are denoted as QD1, QD2 and QD3 respectively. The nonlinear absorption (NLA) properties of the nanoconjugates (InPc-CdSe/ZnS) were investigated with nanosecond laser radiation at 532 nm wavelength. Enhanced NLA properties compared to the InPc alone were observed in the conjugates. The NLA was found to increase with the size of the CdSe/ZnS particles attached to the phthalocyanine. The observed increase was due to the availability of more free-carrier ions in the larger QDs, thus giving rise to the enhanced free-carrier absorption. The measured free-carrier absorption cross-sections (?FCA) are 1.10, 1.65 and 1.95 (×10-19 cm2) for InPc-QD1, InPc-QD2 and InPc-QD3 respectively. The nanoconjugates (InPc-CdSe/ZnS) showed a much lower threshold for optical limiting together with a much lower transmission at high fluences, than the previously reported nanocomposite limiters.

Sanusi, Kayode; Nyokong, Tebello

2014-12-01

128

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

129

Quantum holographic encoding in a two-dimensional electron gas  

SciTech Connect

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

Moon, Christopher

2010-05-26

130

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

131

Electron Localization in the Inhomogeneous Electron Gas: Quantum Point Contacts  

Microsoft Academic Search

We use Quantum Monte Carlo (QMC) techniques to investigate the behavior of electrons in an inhomogeneous quasi-one-dimensional wire as a model of quantum point contact geometries. Previous QMC work by Guclu et al. demonstrated that electrons can be strongly localized in quantum point contacts, and this result was reproduced by Welander et al. using LSDA calculations. We model a quantum

Abhijit C. Mehta; Cyrus J. Umrigar; A. Devrim Guclu; Harold U. Baranger

2011-01-01

132

A quantum chemistry study of natural gas hydrates.  

PubMed

The structure and properties of natural gas hydrates containing hydrocarbons, CO?, and N? molecules were studied by using computational quantum chemistry methods via the density functional theory approach. All host cages involved in I, II, and H types structures where filled with hydrocarbons up to pentanes, CO? and N? molecules, depending on their size, and the structures of these host-guest systems optimized. Structural properties, vibrational spectra, and density of states were analyzed together with results from atoms-in-a-molecule and natural bond orbitals methods. The inclusion of dispersion terms in the used functional plays a vital role for obtaining reliable information, and thus, B97D functional was shown to be useful for these systems. Results showed remarkable interaction energies, not strongly affected by the type of host cage, with molecules tending to be placed at the center of the cavities when host cages and guest molecules cavities are of similar size, but with molecules approaching hexagonal faces for larger cages. Vibrational properties show remarkable features in certain regions, with shiftings rising from host-guest interactions, and useful patterns in the terahertz region rising from water surface vibrations strongly coupled with guest molecules. Likewise, calculations on crystal systems for the I and H types were carried out using a pseudopotential approach combined with Grimme's method to take account of dispersion. PMID:24633777

Atilhan, Mert; Pala, Nezih; Aparicio, Santiago

2014-04-01

133

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

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

134

Prime ideals in quantum algebras   

E-print Network

The central objects of study in this thesis are quantized coordinate algebras. These algebras originated in the 1980s in the work of Drinfeld and Jumbo and are noncommutative analogues of coordinate rings of algebraic ...

Russell, Ewan

135

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

136

White noise approach to the low density limit of a quantum particle in a gas  

E-print Network

The white noise approach to the investigation of the dynamics of a quantum particle interacting with a dilute and in general non-equilibrium gaseous environment in the low density limit is outlined. The low density limit is the kinetic Markovian regime when only pair collisions (i.e., collisions of the test particle with one particle of the gas at one time moment) contribute to the dynamics. In the white noise approach one first proves that the appropriate operators describing the gas converge in the sense of appropriate matrix elements to certain operators of quantum white noise. Then these white noise operators are used to derive quantum white noise and quantum stochastic equations describing the approximate dynamics of the total system consisting of the particle and the gas. The derivation is given ab initio, starting from the exact microscopic quantum dynamics. The limiting dynamics is described by a quantum stochastic equation driven by a quantum Poisson process. This equation then applied to the derivation of quantum Langevin equation and linear Boltzmann equation for the reduced density matrix of the test particle. The first part of the paper describes the approach which was developed by L. Accardi, I.V. Volovich and the author and uses the Fock-antiFock (or GNS) representation for the CCR algebra of the gas. The second part presents the approach to the derivation of the limiting equations directly in terms of the correlation functions, without use of the Fock-antiFock representation. This approach simplifies the derivation and allows to express the strength of the quantum number process directly in terms of the one-particle $S$-matrix.

Alexander Pechen

2006-07-19

137

Fuzzy ideals in $?-$semiring  

E-print Network

In this paper we have studied the relation between the fuzzy left (respectively right) ideals of $\\Gamma-$semiring and that of operator semiring. Thereafter, we have established that the Lattices of all fuzzy left (respectively right) ideal of $\\Gamma-$semiring is equivalent to that of Left operator semiring. Also we have established few properties relating the $k-$ideals and $h-$ideals of $\\Gamma-$semiring with that of operator semiring.

Jayanta Ghosh; T. K. Samanta

2010-10-12

138

Soft Ideals and Arithmetic Mean Ideals  

Microsoft Academic Search

.  This article investigates the soft-interior (se) and the soft-cover (sc) of operator ideals. These operations, and especially\\u000a the first one, have been widely used before, but making their role explicit and analyzing their interplay with the arithmetic\\u000a mean operations is essential for the study in [10] of the multiplicity of traces. Many classical ideals are ‘soft’, i.e.,\\u000a coincide with their

Victor Kaftal; Gary Weiss

2007-01-01

139

Quantum Density of an Inhomogeneous Electron Gas in the Local Oscillator Approximation  

Microsoft Academic Search

Quantum density of an inhomogeneous electron gas is obtained systematically in the local oscillator approximation, by a quantum-statistical mechanical approach. Corrections to the Thomas-Fermi density consist of three parts; the gradient term, the density part oscillating through the change of local potential and the Friedel-oscillation-like part which is modulated by a periodic factor similar to the above one. It is

Tuto Nakamura

1987-01-01

140

Spin-Nematic Squeezing in a Quantum Gas  

E-print Network

Exotic types of magnetic order and phases resulting from collective behaviour of quantum spins are an important focus of many-body physics. Nematic or quadrupolar ordering of spins is one such example, which breaks O(3) rotational symmetry, has no magnetic moment and is analogous to the well-known ordering of molecules in nematic phases of liquid crystals. Spin nematic phases have been posited for a variety of condensed matter systems including frustrated quantum magnets, and heavy-fermion and iron-based superconductors, although they are challenging to detect directly. Spin-1 atomic Bose-Einstein condensates provide a natural system to investigate spin-nematic quantum phases with a key advantage that the nematic tensor is directly measurable. Here, we measure spin-nematic fluctuations in a spin-1 condensate following a quench through a nematic to ferromagnetic quantum phase transition and observe quadrature squeezing in the variance of the fluctuations up to -8.3 dB (-10.3 dB corrected for detection noise) b...

Hamley, C D; Hoang, T M; Bookjans, E M; Chapman, M S

2011-01-01

141

Quantum fluctuations of the vortex-lattice state in an ultrafast rotating Bose gas  

Microsoft Academic Search

Quantum fluctuations in an ultrafast rotating Bose gas at zero temperature are investigated. We calculate the condensate density perturbatively to show that no condensate is present in the thermodynamic limit. The excitation from Gaussian fluctuations around the mean-field solution causes infrared divergences in loop diagrams, nevertheless, in calculating the atom number density, the correlation functions and the free energy, we

Qiong Li; Bo Feng; Dingping Li

2011-01-01

142

Quantum Monte Carlo Calculations of the Energy of the Relativistic Homogeneous Electron Gas  

NASA Astrophysics Data System (ADS)

The ground state energy of the unpolarized homogeneous electron gas at zero temperature is calculated within the density range rs = 0.1-10, incorporating relativistic effects via first-order perturbation theory. Accurate nonrelativistic wave functions and variational and diffusion quantum Monte Carlo techniques are used to calculate the required expectation values.

Kenny, S. D.; Rajagopal, G.; Needs, R. J.; Leung, W.-K.; Godfrey, M. J.; Williamson, A. J.; Foulkes, W. M. C.

1996-08-01

143

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

144

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

145

Monomial Gorenstein ideals  

Microsoft Academic Search

The paper concerns itself with generating sets for monomial Gorenstein ideals in polynomial rings k[x1,..., xr], k an arbitrary field. For r=5 it is shown that for a certain class of these ideals, the number of generators is bounded by 13. To establish the sharpness of this bound an algorithm is established, to obtain all numerical symmetric semigroups with a

Henrik Bresinsky

1979-01-01

146

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

147

Zigzag Phase Transition in Quantum Wires and Localization in the Inhomogeneous One-Dimensional Electron Gas  

NASA Astrophysics Data System (ADS)

In this work, we study two important themes in the physics of the interacting one-dimensional (1D) electron gas: the transition from one-dimensional to higher dimensional behavior, and the role of inhomogeneity. The interplay between interactions, reduced dimensionality, and inhomogeneity drives a rich variety of phenomena in mesoscopic physics. In 1D, interactions fundamentally alter the nature of the electron gas, and the homogeneous 1D electron gas is described by Luttinger Liquid theory. We use Quantum Monte Carlo methods to study two situations that are beyond Luttinger Liquid theory---the quantum phase transition from a linear 1D electron system to a quasi-1D zigzag arrangement, and electron localization in quantum point contacts. Since the interacting electron gas has fundamentally different behavior in one dimension than in higher dimensions, the transition from 1D to higher dimensional behavior is of both practical and theoretical interest. We study the first stage in such a transition; the quantum phase transition from a 1D linear arrangement of electrons in a quantum wire to a quasi-1D zigzag configuration, and then to a liquid-like phase at higher densities. As the density increases from its lowest values, first, the electrons form a linear Wigner crystal; then, the symmetry about the axis of the wire is broken as the electrons order in a quasi-1D zigzag phase; and, finally, the electrons form a disordered liquid-like phase. We show that the linear to zigzag phase transition occurs even in narrow wires with strong quantum fluctuations, and that it has characteristics which are qualitatively different from the classical transition. Experiments in quantum point contacts (QPC's) show an unexplained feature in the conductance known as the "0.7 Effect''. The presence of the 0.7 effect is an indication of the rich physics present in inhomogeneous systems, and we study electron localization in quantum point contacts to evaluate several different proposed mechanisms for the 0.7 effect. We show that electrons form a Wigner crystal in a 1D constriction; for sharp constriction potentials the localized electrons are separated from the leads by a gap in the density, while for smoother potentials, the Wigner crystal is smoothly connected to the leads. Isolated bound states can also form in smooth constrictions if they are sufficiently long. We thus show that localization can occur in QPC's for a variety of potential shapes and at a variety of electron densities. These results are consistent with the idea that the 0.7 effect and bound states observed in quantum point contacts are two distinct phenomena.

Mehta, Abhijit C.

148

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

149

Cooling an electron gas using quantum dot based electronic refrigeration  

E-print Network

and theoretical investigation of a re- frigeration scheme that has the potential to cool 2DEGs below the temperatures currently available. Cooling to ever lower temperatures would be beneficial for studying fragile fractional quantum Hall states, non-Fermi-liquid... dots. Conventionally, low temperature measurements of 2DEGs are made by cooling the sample to 1.5 K with liquid Helium-4, to 300 mK with liquid Helium-3, or even down to a few mK using a dilution refrigerator. However, at lower temperatures the electron...

Prance, Jonathan Robert

2009-10-13

150

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

E-print Network

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

D. Ivanov; S. Wallentowitz

2006-03-16

151

Creation and Detection of a Mesoscopic Gas in a Nonlocal Quantum Superposition  

SciTech Connect

We investigate the scattering of a quantum matter wave soliton on a barrier in a one-dimensional geometry, and we show that it can lead to mesoscopic quantum superposition states, where the atomic gas is in a coherent superposition of being in the half-space to the left of the barrier and being in the half-space to the right of the barrier. We propose an interferometric method to reveal the coherent nature of this superposition, and we discuss in detail the experimental feasibility.

Weiss, Christoph; Castin, Yvan [Laboratoire Kastler Brossel, Ecole Normale Superieure, UPMC and CNRS, 24 rue Lhomond, 75231 Paris Cedex 05 (France)

2009-01-09

152

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

153

Approximate Solutions of Quantum Equations for Electron Gas in Plasma  

E-print Network

We have obtained the solutions of linearized Shr{\\"o}dinger equation for spherically and axially symmetrical electrons density oscillations in plasma in the approximation of the self-consistent field. It was shown that in the center or on the axis of symmetry of such a system the static density of electrons can enhance, which leads to the increasing of density and pressure of ion gas. We suggest that this mechanism could be realized in nature as rare phenomenon called the 'fireball' and could be used in carrying out the research concerning controlled fusion.

M. Dvornikov; S. Dvornikov; G. Smirnov

2002-03-14

154

OBTAINING LAWS OF THERMODYNAMICS FOR IDEAL GASES USING ELASTIC COLLISIONS  

E-print Network

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

Montgomery-Smith, Stephen

155

`Quantum explosion' of a trapped one-dimensional Bose gas  

E-print Network

We analyze free expansion of a trapped one-dimensional Bose gas after a sudden release from the confining trap potential. By using the stationary phase and local density approximations, we show that the long-time asymptotic density profile and the momentum distribution of the gas are determined by the initial distribution of Bethe rapidities (quasimomenta) and hence can be obtained from the solutions to the thermodynamic Bethe ansatz equations. For expansion from a harmonic trap, and in the limits of very weak and very strong interactions, we recover the known scaling solutions of the hydrodynamic approach corresponding to self-similar expansion. For all other power-law traps and arbitrary interaction strengths, the expansion is not self-similar and shows strong dependence on the trap anharmonicity of the shape variation of the density profile during evolution. We also characterize dynamical fermionization of an expanding cloud in terms of its first- and second-order coherences describing phase and density fluctuations.

A. S. Campbell; D. M. Gangardt; K. V. Kheruntsyan

2015-01-08

156

Quantum Monte Carlo simulation of a two-dimensional Bose gas  

SciTech Connect

The equation of state of a homogeneous two-dimensional Bose gas is calculated using quantum Monte Carlo methods. The low-density universal behavior is investigated using different interatomic model potentials, both finite ranged and strictly repulsive and zero ranged, supporting a bound state. The condensate fraction and the pair distribution function are calculated as a function of the gas parameter, ranging from the dilute to the strongly correlated regime. In the case of the zero-range pseudopotential we discuss the stability of the gaslike state for large values of the two-dimensional scattering length, and we calculate the critical density where the system becomes unstable against cluster formation.

Pilati, S. [Dipartimento di Fisica, Universita di Trento and CRS-BEC INFM, I-38050 Povo (Italy); Departament de Fisica i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain); Boronat, J.; Casulleras, J. [Departament de Fisica i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain); Giorgini, S. [JILA, University of Colorado, Boulder, Colorado 80309-0440 (United States); Dipartimento di Fisica, Universita di Trento and CRS-BEC INFM, I-38050 Povo (Italy)

2005-02-01

157

Liquid-to-gas phase transitions in two-dimensional quantum systems at zero temperature  

Microsoft Academic Search

Two-dimensional systems of bosons and fermions are studied at zero temperature by means of variational calculations. When viewed as a function of the quantum parameter? = ?2\\/m?S in the variational context, bosons are found to undergo a second-order liquid-to-gas transition, whereas, contrary to expectations, fermions are found to undergo a first-order transition with a region in which liquid and gaseous

M. D. Miller; L. H. Nosanow

1978-01-01

158

Pulsed Quantum-Cascade Laser-Based Sensor for Trace-Gas Detection of Carbonyl Sulfide  

Microsoft Academic Search

Simultaneous exhaled carbonyl sulfide (OCS) and carbon dioxide concentration measurements in human breath are demonstrated with a compact pulsed quantum-cascade laser-based gas sensor. We achieved a noise-equivalent sensitivity (1sigma) of 1.2 parts per billion by measuring a well-isolated OCS P(11) absorption line in the nu3 band at 2057.6 cm^-1 using an astigmatic Herriott cell of 36-m optical path length and

Gerard Wysocki; Matt McCurdy; Stephen So; Damien Weidmann; Chad Roller; Robert F. Curl; Frank K. Tittel

2004-01-01

159

Quantum Monte Carlo investigations of density functional theory of the strongly inhomogeneous electron gas  

Microsoft Academic Search

We use a variational quantum Monte Carlo realization of the adiabatic connection technique to calculate the most relevant quantities in Hohenberg-Kohn-Sham density functional theory for several strongly inhomoge- neous electron-gas systems. Results for the coupling-constant dependence of the exchange-correlation energy, the pair-correlation function, the exchange-correlation hole, and the exchange and correlation energy densities are presented. Comparisons are made with the

Maziar Nekovee; W. Foulkes; R. Needs

2003-01-01

160

Quantum Monte Carlo investigations of density functional theory of the strongly inhomogeneous electron gas  

Microsoft Academic Search

We use a variational quantum Monte Carlo realization of the adiabatic connection technique to calculate the most relevant quantities in Hohenberg-Kohn-Sham density functional theory for several strongly inhomogeneous electron-gas systems. Results for the coupling-constant dependence of the exchange-correlation energy, the pair-correlation function, the exchange-correlation hole, and the exchange and correlation energy densities are presented. Comparisons are made with the interaction

Maziar Nekovee; W. M. Foulkes; R. J. Needs

2003-01-01

161

Quantum Monte Carlo Analysis of Exchange and Correlation in the Strongly Inhomogeneous Electron Gas  

Microsoft Academic Search

We use the variational quantum Monte Carlo method to calculate the density-functional exchange-correlation hole n{sub xc} , the exchange-correlation energy density e{sub xc} , and the total exchange-correlation energy E{sub xc} of several strongly inhomogeneous electron gas systems. We compare our results with the local density approximation and the generalized gradient approximation. It is found that the nonlocal contributions to

Maziar Nekovee; W. M. C. Foulkes; R. J. Needs

2001-01-01

162

Quantum Monte Carlo Analysis of Exchange and Correlation in the Strongly Inhomogeneous Electron Gas  

Microsoft Academic Search

We use the variational quantum Monte Carlo method to calculate the density-functional exchange-correlation hole nxc, the exchange-correlation energy density exc, and the total exchange-correlation energy Exc of several strongly inhomogeneous electron gas systems. We compare our results with the local density approximation and the generalized gradient approximation. It is found that the nonlocal contributions to exc contain an energetically significant

Maziar Nekovee; W. M. Foulkes; R. J. Needs

2001-01-01

163

InAs self-assembled quantum dots as controllable scattering centers near a two-dimensional electron gas  

Microsoft Academic Search

InAs self-assembled quantum dots are grown in the vicinity of a two-dimensional electron gas. Transport experiments show a progressive reduction of the electron mobility with increasing dot density, which indicates the influence of the quantum dots on the electrical properties of the electron gas. A saturation of the mobility is observed for the highest dot density samples. Transmission electron microscopy

E. Ribeiro; E. Müller; T. Heinzel; H. Auderset; K. Ensslin; G. Medeiros-Ribeiro; P. M. Petroff

1998-01-01

164

Quantum cascade laser intracavity absorption spectrometer for trace gas A. V. Muraviev, D. E. Maukonen, C. J. Fredricksen, Gautam Medhi, and R. E. Peale  

E-print Network

Quantum cascade laser intracavity absorption spectrometer for trace gas sensing A. V. Muraviev, D://apl.aip.org/authors #12;Quantum cascade laser intracavity absorption spectrometer for trace gas sensing A. V. Muraviev, D is demonstrated. An external-cavity multi-mode quantum cascade laser with central wavelength 8.0 lm was combined

Peale, Robert E.

165

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

E-print Network

In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by Loop quantum cosmology. Dark energy in the form of Generalised Cosmic Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is taken into account in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy model. Graphs and phase diagrams are drawn to study the variations of these parameters. It is seen that the background dynamics of Generalised Cosmic Chaplygin gas is completely consistent with the notion of an accelerated expansion in the late universe. From the graphs, generalised cosmic Chaplygin gas is identified as a dark fluid with a lesser nega...

Chowdhury, Ratul

2012-01-01

166

Vlasov hydrodynamics of a quantum mechanical model  

Microsoft Academic Search

We derive the Vlasov hydrodynamics from the microscopic equations of a quantum mechanical model, which simulates that of an assembly of gravitating particles. In addition we show that the local microscopic dynamics of the model corresponds, on a suitable time-scale, to that of an ideal Fermi gas.

Heide Narnhofer; Geoffrey L. Sewell

1981-01-01

167

Quantum plasmas with or without a uniform magnetic field. II. Exact low-density free energy  

Microsoft Academic Search

The exact analytical expression of the free energy f of a quantum Coulomb plasma in the presence of a uniform magnetic field B0 is produced at low density rho. This regime corresponds to low degeneracy, weak Coulomb coupling but any strength of the magnetic field and fully quantum dynamics. Thus f is expanded around its value for an ideal gas

F. Cornu

1998-01-01

168

Optical spectral imaging of a single layer of a quantum gas with an ultranarrow optical transition  

NASA Astrophysics Data System (ADS)

We demonstrated high-sensitivity optical spectral imaging of a single layer of a quantum gas of ytterbium atoms in a two-dimensional optical lattice using the ultranarrow 1S0-3P2 transition. We successfully obtained a set of excitation-frequency-dependent fluorescence images with an excitation laser of the linewidth of 1 kHz (FWHM), and the overall features were well explained by considering the inhomogeneous light shift originating from the Gaussian beam shape of the optical lattice potential which provided the steepest potential gradient of 3.6 kHz/?m. This result is also the successful demonstration of the tunable local atom addressing along the equipotential contour depending on the excitation laser frequency with the frequency resolution of 8 kHz and the spatial resolution of approximately 2 ?m. The demonstrated technique will be useful for many purposes including the measurement of interaction shift in the study of a quantum gas and quantum information processing.

Shibata, Kosuke; Yamamoto, Ryuta; Seki, Yu; Takahashi, Yoshiro

2014-03-01

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

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

171

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

SciTech Connect

Quantum cascade lasers (QCLs) are increasingly being used to detect, identify, and measure levels of trace gases in the air. External cavity QCLs (ECQCLs) provide a broadly-tunable infrared source to measure absorption spectra of chemicals and provide high detection sensitivity and identification confidence. Applications include detecting chemical warfare agents and toxic industrial chemicals, monitoring building air quality, measuring greenhouse gases for atmospheric research, monitoring and controlling industrial processes, analyzing chemicals in exhaled breath for medical diagnostics, and many more. Compact, portable trace gas sensors enable in-field operation in a wide range of platforms, including handheld units for use by first responders, fixed installations for monitoring air quality, and lightweight sensors for deployment in unmanned aerial vehicles (UAVs). We present experimental demonstration of a new chemical sensing technique based on intracavity absorption in an external cavity quantum cascade laser (ECQCL). This new technique eliminates the need for an infrared photodetector and gas cell by detecting the intracavity absorption spectrum in the compliance voltage of the laser device itself. To demonstrate and characterize the technique, we measure infrared absorption spectra of chemicals including water vapor and Freon-134a. Sub-ppm detection limits in one second are achieved, with the potential for increased sensitivity after further optimization. The technique enables development of handheld, high-sensitivity, and high-accuracy trace gas sensors for in-field use.

Phillips, Mark C.; Taubman, Matthew S.

2013-06-04

172

Quantum fluctuations of the vortex-lattice state in an ultrafast rotating Bose gas  

SciTech Connect

Quantum fluctuations in an ultrafast rotating Bose gas at zero temperature are investigated. We calculate the condensate density perturbatively to show that no condensate is present in the thermodynamic limit. The excitation from Gaussian fluctuations around the mean-field solution causes infrared divergences in loop diagrams, nevertheless, in calculating the atom number density, the correlation functions and the free energy, we find that the sum of the divergences in the same loop order vanishes and we obtain finite physical quantities. The long-range correlation is explored and the algebraic decay exponent for the single-particle correlation function is obtained. The atom number density distribution is obtained at the one-loop level, which illustrates the quantum fluctuation effects to melt the mean-field vortex lattice. By the nonperturbative Gaussian variational method, we locate the spinodal point of the vortex-lattice state.

Li Qiong; Feng Bo; Li Dingping [Department of Physics, Peking University, Beijing 100871 (China)

2011-04-15

173

Quantum fluctuations of the vortex-lattice state in an ultrafast rotating Bose gas  

NASA Astrophysics Data System (ADS)

Quantum fluctuations in an ultrafast rotating Bose gas at zero temperature are investigated. We calculate the condensate density perturbatively to show that no condensate is present in the thermodynamic limit. The excitation from Gaussian fluctuations around the mean-field solution causes infrared divergences in loop diagrams, nevertheless, in calculating the atom number density, the correlation functions and the free energy, we find that the sum of the divergences in the same loop order vanishes and we obtain finite physical quantities. The long-range correlation is explored and the algebraic decay exponent for the single-particle correlation function is obtained. The atom number density distribution is obtained at the one-loop level, which illustrates the quantum fluctuation effects to melt the mean-field vortex lattice. By the nonperturbative Gaussian variational method, we locate the spinodal point of the vortex-lattice state.

Li, Qiong; Feng, Bo; Li, Dingping

2011-04-01

174

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

NASA Astrophysics Data System (ADS)

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

Yurishchev, M. A.

2014-11-01

175

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

176

Weakly Relativistic Quantum Effects in a Two-Dimensional Electron Gas: Dispersion of Langmuir Waves  

NASA Astrophysics Data System (ADS)

A weakly-relativistic quantum-hydrodynamic model for charged spinless particles applied to low-dimensional systems is described in detail. The equations are constructed in the self-consistent field approximation. The Darwin term, the current-current interaction, and the weakly relativistic correction to the kinetic energy, all described by the Breit Hamiltonian, are considered together with the Coulomb interaction. The contributions of the described effects and also of relativistic-temperature effects to the dispersion of the Langmuir waves in a two-dimensional electron gas are calculated. A comparison with the corresponding formula for a three-dimensional system of particles is presented.

Andreev, P. A.; Ivanov, A. Yu.

2015-01-01

177

Quantum Monte Carlo Analysis of Exchange and Correlation in the Strongly Inhomogeneous Electron Gas  

SciTech Connect

We use the variational quantum Monte Carlo method to calculate the density-functional exchange-correlation hole n{sub xc} , the exchange-correlation energy density e{sub xc} , and the total exchange-correlation energy E{sub xc} of several strongly inhomogeneous electron gas systems. We compare our results with the local density approximation and the generalized gradient approximation. It is found that the nonlocal contributions to e{sub xc} contain an energetically significant component, the magnitude, shape, and sign of which are controlled by the Laplacian of the electron density.

Nekovee, Maziar; Foulkes, W. M. C.; Needs, R. J.

2001-07-16

178

Quantum Monte Carlo analysis of exchange and correlation in the strongly inhomogeneous electron gas.  

PubMed

We use the variational quantum Monte Carlo method to calculate the density-functional exchange-correlation hole n(xc), the exchange-correlation energy density e(xc), and the total exchange-correlation energy E(xc) of several strongly inhomogeneous electron gas systems. We compare our results with the local density approximation and the generalized gradient approximation. It is found that the nonlocal contributions to e(xc) contain an energetically significant component, the magnitude, shape, and sign of which are controlled by the Laplacian of the electron density. PMID:11461577

Nekovee, M; Foulkes, W M; Needs, R J

2001-07-16

179

Ideal Integrating Bolometer  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

180

Delivering ideal employee experiences.  

PubMed

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

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

2009-05-01

181

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

PubMed

The accurate description of the complexation of the CUO molecule by Ne and Ar noble gas matrices represents a challenging task for present-day quantum chemistry. Especially, the accurate prediction of the spin ground state of different CUO-noble-gas complexes remains elusive. In this work, the interaction of the CUO unit with the surrounding noble gas matrices is investigated in terms of complexation energies and dissected into its molecular orbital quantum entanglement patterns. Our analysis elucidates the anticipated singlet-triplet ground-state reversal of the CUO molecule diluted in different noble gas matrices and demonstrates that the strongest uranium-noble gas interaction is found for CUOAr4 in its triplet configuration. PMID:24263815

Tecmer, Pawe?; Boguslawski, Katharina; Legeza, Örs; Reiher, Markus

2014-01-14

182

Optically multiplexed multi-gas detection using quantum cascade laser photoacoustic spectroscopy.  

PubMed

We report high-throughput, nondispersive optical multiplexing of laser beams using a scanning galvanometer. We have utilized this technique for multispecies trace-gas detection using multiple quantum cascade laser photoacoustic spectroscopy. We demonstrate switching from one laser to another in less than 1 s, a performance level needed for a comprehensive multispecies sensor, and a high signal-to-noise ratio detection of five gaseous components, NH(3), NO(2), dimethyl methyl phosphonate (DMMP, a simulant for nerve agents), acetone, and ethylene glycol, in a room air gas mixture containing approximately 3 ppb of NH(3), approximately 8 ppb of NO(2), approximately 20 ppb of DMMP, approximately 30 ppb of acetone, and approximately 40 ppb of ethylene glycol. PMID:18806847

Mukherjee, Anadi; Prasanna, Manu; Lane, Michael; Go, Rowel; Dunayevskiy, Ilya; Tsekoun, Alexei; Patel, C Kumar N

2008-09-20

183

Current fluctuations in an ideally conducting contact  

Microsoft Academic Search

It is shown that the shot noise at finite frequency in an ideally conducting contact is finite. The complete formula for the\\u000a current correlation function at finite frequency is presented for a quantum conductor, where the electron transport can be\\u000a adequately described in a model of noninteracting electrons using a scattering matrix. It is indicated that the description\\u000a of electron

G. B. Lesovik; L. D. Landau

1999-01-01

184

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

E-print Network

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

Ratul Chowdhury; Prabir Rudra

2012-04-13

185

DIPPR Project 871 For 1995 - Thermodynamic Properties and Ideal-Gas Enthalpies of Formation for Methyl Benzoate, Ethyl Benzoate, (R)-(+)-Limonene, Tert-Amyl Methyl Ether, Trans-Crotonaldehyde, and  

SciTech Connect

Ideal-gas enthalpies of formation of methyl benzoate, ethyl benzoate, (R)-(+)-limonene, tert-amyl methyl ether, trans-crotonaldehyde, and diethylene glycol are reported. The standard energy of combustion and hence standard enthalpy of formation of each compound in the liquid phase has been measured using an oxygen rotating-bomb calorimeter without rotation. Vapor pressures were measured to a pressure limit of 270 kPa or the lower decomposition point for each of the six compounds using a twin ebulliometric apparatus. Liquid-phase densities along the saturation line were measured for each compound over a range of temperature (ambient to a maximum of 548 K). A differential scanning calorimeter was used to measure two-phase (liquid + vapor) heat capacities for each compound in the temperature region ambient to the critical temperature or lower decomposition point. For methyl benzoate and tert-amyl methyl ether, critical temperatures and critical densities were determined from the DSC results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for each of the remaining compounds. The results of the measurements were combined to derive a series of thermophysical properties including critical temperature, critical density, critical pressure, acentric factor, enthalpies of vaporization (restricted to within {+-}50 K of the temperature region of the experimentally determined vapor pressures), and heat capacities along the saturation line. Wagner-type vapor-pressure equations were derived for each compound. All measured and derived values were compared with those obtained in a search of the literature. Recommended critical parameters are listed for each of the compounds studied. Group-additivity parameters, useful in the application of the Benson gas-phase group-contribution correlations, were derived.

Steele, W.V.

2002-07-01

186

Multi-quantum excitation in optically pumped alkali atom: rare gas mixtures  

NASA Astrophysics Data System (ADS)

Diode-pumped alkali laser (DPAL) technology offers a means of achieving high-energy gas laser output through optical pumping of the D-lines of Cs, Rb, and K. The exciplex effect, based on weak attractive forces between alkali atoms and polarizable rare gas atoms (Ar, Kr, Xe), provides an alternative approach via broadband excitation of exciplex precursors (XPAL). In XPAL configurations, we have observed multi-quantum excitation within the alkali manifolds which result in infrared emission lines between 1 and 4 ?m. The observed excited states include the 42FJ states of both Cs and Rb, which are well above the two-photon energy of the excitation laser in each case. We have observed fluorescence from multi-quantum states for excitation wavelengths throughout the exciplex absorption bands of Cs-Ar, Cs-Kr, and Cs-Xe. The intensity scaling is roughly first-order or less in both pump power and alkali concentration, suggesting a collisional energy pooling excitation mechanism. Collisional up-pumping appears to present a parasitic loss term for optically pumped atomic systems at high intensities, however there may also be excitation of other lasing transitions at infrared wavelengths.

Galbally-Kinney, K. L.; Rawlins, W. T.; Davis, S. J.

2014-03-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

188

The ideal satellite pharmacy.  

PubMed

The pharmacy service at the Seattle Veterans Administration Medical Center moved into a replacement facility in September 1986. A description of the present medical center and the satellite pharmacy is presented. The ideal satellite pharmacy for this medical center is then described. The satellite is discussed with respect to the satellite door, transportation systems (i.e., dumbwaiter, pneumatic tubes), communication systems (i.e., Omnifax, intercom, typewriter, telephone, computer), equipment (i.e., IV hood, refrigerator, shelving), stock, and space. Because each medical center has specific needs and equipment available, the information presented should be used as a guide when designing a satellite pharmacy. PMID:10280299

Suzuki, N T

1987-02-01

189

Traces, ideals, and arithmetic means  

Microsoft Academic Search

This article grew out of recent work of Dykema, Figiel, Weiss, and Wodzicki (Commutator structure of operator ideals) which inter alia characterizes commutator ideals in terms of arithmetic means. In this paper we study ideals that are arithmetically mean (am) stable, am-closed, am-open, soft-edged and soft-complemented. We show that many of the ideals in the literature possess such properties. We

Victor Kaftal; Gary Weiss

2002-01-01

190

Unified theory of ideals  

NASA Astrophysics Data System (ADS)

Unified field theories try to merge the internal symmetries of the standard model into a single group. Here we lay out something different. We give evidence that a theory may be ultraunified; that is, beyond aiming to unify the internal symmetries into a single group, those groups may be unified together with the quarks and leptons that they act on. Furthermore, the (3+1) Lorentz transformations may likewise be unified with the scalars, spinors, four-vectors, and field strength tensors that they act on. These simplifications occur because the representations can be found in the form of an algebra acting on itself. The approach described in this paper is meant to tie everything into the Dixon algebra: R?C?H?O, the tensor product of the division algebras, whose connection to the standard model was earlier advocated for in Dixon [Division Algebras: Octonions, Quaternions, Complex Numbers and the Algebraic Design of Physics (Kluwer Academic Publishers, Dordrecht, 1994).]. Here we propose a principle of ideals, which states that particle sectors of the standard model are given by generalized ideals of the algebra. As we show, this method very quickly uncovers all of the Lorentz representations of the standard model and one full generation of quarks and leptons.

Furey, Cohl

2012-07-01

191

GaInAs(P)\\/InP quantum well structures grown by gas source molecular beam epitaxy  

Microsoft Academic Search

We describe optical properties of single and multiple quantum well structures grown by gas source molecular beam epitaxy. Absorption and photoluminescence were used in conjunction with x-ray and transmission electron microscopy techniques to determine the confined particle energy levels and well thicknesses. Well defined exciton transitions were observed in the ternary and quaternary well superlattices even above room temperature. In

H. Temkin; M. B. Panish; P. M. Petroff; R. A. Hamm; J. M. Vandenberg; S. Sumski

1985-01-01

192

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

PubMed

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

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

2011-02-01

193

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

PubMed Central

Biomolecular nucleophilic substitution reactions, SN2, 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 SN2 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 SN2 barrier heights in gas phase for substituted methyl halide systems, R1R2R3CX, reacting with fluorine anion where R1, R2, and R3 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 SN2 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 wavefunction theory for these systems via the natural bond orbital analysis. PMID:20377265

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

2010-01-01

194

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; Wójcik, Aleksander K.; Belyanin, Alexey A.; Kono, Junichiro

2013-01-01

195

Fractional quantum Hall states of a Bose gas with a spin-orbit coupling  

NASA Astrophysics Data System (ADS)

We study the fractional quantum Hall phases of a pseudospin-1/2 Bose gas in an artificial gauge field. In addition to an external magnetic field, the gauge field mimics an intrinsic spin-orbit coupling of the Rashba type. While the spin degeneracy of the Landau levels is lifted by the spin-orbit coupling, the crossing of two Landau levels at certain coupling strengths gives rise to a new degeneracy. We therefore take into account two Landau levels and perform exact diagonalization of the many-body Hamiltonian. We study and characterize the quantum Hall phases which occur in the vicinity of the degeneracy point. Notably, we describe the different states appearing at the Laughlin fillings, ? = 1/2 and ? = 1/4. While for these filling factors incompressible phases disappear at the degeneracy point, we find gaps in the spectra of denser systems at ? = 3/2 and ? = 2. For filling factors ? = 2/3 and ? = 4/3, we discuss the connection of the exact ground states to the non-Abelian spin singlet states, obtained as the ground states of (k + 1)-body contact interactions.

Graß, T.; Juliá-Díaz, B.; Burrello, M.; Lewenstein, M.

2013-07-01

196

Renormalization Theory of a Two Dimensional Bose Gas: Quantum Critical Point and Quasi-Condensed State  

NASA Astrophysics Data System (ADS)

We present a renormalization group construction of a weakly interacting Bose gas at zero temperature in the two-dimensional continuum, both in the quantum critical regime and in the presence of a condensate fraction. The construction is performed within a rigorous renormalization group scheme, borrowed from the methods of constructive field theory, which allows us to derive explicit bounds on all the orders of renormalized perturbation theory. Our scheme allows us to construct the theory of the quantum critical point completely, both in the ultraviolet and in the infrared regimes, thus extending previous heuristic approaches to this phase. For the condensate phase, we solve completely the ultraviolet problem and we investigate in detail the infrared region, up to length scales of the order (? ^3? _0)^{-1/2} (here ? is the interaction strength and ? _0 the condensate density), which is the largest length scale at which the problem is perturbative in nature. We exhibit violations to the formal Ward Identities, due to the momentum cutoff used to regularize the theory, which suggest that previous proposals about the existence of a non-perturbative non-trivial fixed point for the infrared flow should be reconsidered.

Cenatiempo, S.; Giuliani, A.

2014-07-01

197

Three-Level Maser Action in Gas I. Theory of Multiple Quantum Transition and Doppler Effect in Three-Level Gas Maser  

Microsoft Academic Search

The multiple quantum process in the off-resonant condition of the three-level gas maser is discussed. The intensity of the emission produced by this process is calculated by a perturbation theory and also by a more general treatment which is the application of Javan's theory to the off-resonant case. Some graphical representations of the signal line under off-resonant pumping are given

Tatsuo Yajima

1961-01-01

198

Quantum linear Boltzmann equation with finite intercollision time  

E-print Network

Inconsistencies are pointed out in the usual quantum versions of the classical linear Boltzmann equation constructed for a quantized test particle in a gas. These are related to the incorrect formal treatment of momentum decoherence. We prove that ideal collisions would result in complete momentum decoherence, the persistence of coherence is only due to the finite intercollision time. A corresponding novel quantum linear Boltzmann equation is proposed.

Lajos Diosi

2009-05-25

199

Quantum linear Boltzmann equation with finite intercollision time  

E-print Network

Inconsistencies are pointed out in the usual quantum versions of the classical linear Boltzmann equation constructed for a quantized test particle in a gas. These are related to the incorrect formal treatment of momentum decoherence. We prove that ideal collisions would result in complete momentum decoherence, the persistence of coherence is only due to the finite intercollision time. A corresponding novel quantum linear Boltzmann equation is proposed.

Diosi, Lajos

2009-01-01

200

Quantum linear Boltzmann equation with finite intercollision time  

SciTech Connect

Inconsistencies are pointed out in the usual quantum versions of the classical linear Boltzmann equation constructed for a quantized test particle in a gas. These are related to the incorrect formal treatment of momentum decoherence. We prove that ideal collisions with the molecules would result in complete momentum decoherence, the persistence of coherence is only due to the finite intercollision time. A corresponding quantum linear Boltzmann equation is proposed.

Diosi, Lajos [Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest 114 (Hungary)

2009-12-15

201

Modulation potential effects on the quantum magnetotransport in a two-dimensional electron gas  

NASA Astrophysics Data System (ADS)

The quantum magnetotransport (QMT) coefficients of a two-dimensional electron gas (2DEG) in a perpendicular magnetic field for the 2D square array of modulated anti-dot (AD) and in quantum dot (QD)-limit potentials and 1D Quantum Wire (QW) are calculated in the low magnetic field region (<0.3 T) using the Kubo method. The model potential is modulated by controlling the steepness and its strength. The effect on the band part of all QMT coefficients are studied. Our analysis is based on how the sub Landau Level states sue to new magnetic Brillouin zone (MBZ) affect the QMT coefficients, how the cyclotron orbit and the scattering by the potential contribute to the QMT coefficients, and how the states near the Fermi level and below the Fermi level contribute to the QMT coefficients when the size and the strength of the modulated potential are changed. The results for 2D modulation show that (i) Oscillations associated with the filling of sub Landau levels occur in sigmasbsp{xx}{(0)} and sigmasbsp{yx}{(0)} for the low modulation case. (ii) The effect of scattering by the AD potential is quite different from that by the dot potential. (iii) For a strong lateral superlattice AD potential, the longitudinal resistivity rhosbsp{xx}{(0)} has a double peak structure which depends on both the strength of the modulation potential as well as its slope. (iv) For both the AD and QD potentials, rhosbsp{xy}{(0)} is quenched and is negative at low magnetic fields which depend on the size and the strength of the modulation. (v) For the strong dot potential, there are Aharanov-Bohm oscillations in rhosbsp{xx}{(0)} and rhosbsp{xy}{(0)} and large plus-to-minus oscillations. The double peak structure in rhosbsp{xx}{(0)} and the negative values and quenching of the Hall effect at low magnetic fields have been observed experimentally for AD in both the quasiclassical and quantum regimes. In 1D modulation, all the QMT coefficients of a 2DEG in a perpendicular magnetic field for the Short Quantum Wire are calculated in the low magnetic field region (<0.3 T) using the Kubo method. The Quantum Wire Channel is modulated by controlling the steepness and its strength of the potential barrier. Our studies show a step-like feature in transverse conductivities due to the Landau Level (LL) crossing for the weak modulation and low-field giant peaks in the transverse resistivities for the strong potential. And also, quenched Hall resistivities at low magnetic fields are presented. In longitudinal resistivities, some threshold peaks are shown. Our interesting feature is the negative Hall resistivities which are guessed as the result of the boundary back-scattering in the short Quantum Wire.

Park, Tae-Ik

202

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

203

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

NASA Astrophysics Data System (ADS)

Both experimental and theoretical investigations are reported on the infrared spectrum of vinylphosphine-borane (CH2=CHPH2?BH3), 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 ?,?-unsaturated phosphine-borane synthesized up to now is kinetically very unstable in the gas phase and decomposes rapidly into two fragments: the free vinylphosphine CH2=CHPH2 and the monoborane BH3 which dimerizes to form the more stable diborane B2H6. Spectra of free CH2=CHPH2 and B2H6 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 CH2=CHPH2 and BH3 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 ??=?complex-?monomer to make the effect of the complexation precise on each localized mode. In this objective, anharmonic frequencies and infrared intensities of the BH3 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 ?,?-unsaturated phosphine by borane on the physicochemical properties of the formed 12-atom complex have been efficiently evaluated.

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

2008-12-01

204

Uncountably Generated Ideals of Functions  

ERIC Educational Resources Information Center

Maximal ideals in the ring of continuous functions on the closed interval [0, 1] are not finitely generated. This is well-known. What is not as well-known, but perhaps should be, is the fact that these ideals are not countably generated although the proof is not harder! We prove this here and use the result to produce some non-prime ideals in the…

Sury, B.

2011-01-01

205

Closure Operations on Ideals by  

E-print Network

Closure Operations on Ideals by Sara Faridi . . . . . . . . . . . . . . . . . . . . . . . . . . * *. . . . . . . . 5 2.1Integral Closure . . . . . . . . . . . . . . . . . . . . . . . . .* * . . . . . . . . . 5 2.2Integral Closure of Graded Rings and Rees Rings . . . . . . . . . * *. . . . . . 8

Faridi, Sara

206

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 collisions Newtonian. For example, the motion is reversible, thus demonstrating that the second law of thermodynamics

Montgomery-Smith, Stephen

207

Space Sciences and Idealism  

NASA Astrophysics Data System (ADS)

Erwin Schrodinger suggested that " Scientific knowledge forms part of the idealistic background of human life", which exalted man from a nude and savage state to true humanity [Science and Humanism, Cambridge, 1961, p9]. Modern space sciences an space exploration are a brilliant demonstration of the validity of Schrodinger's thesis on Idealism. Moreover, Schrodingers thesis could be considered also as a basic principle for the New Educational Space Philosophical Project "TIMAEUS"."TIMAEUS" is not only an attempt to to start a new dialogue between Science, the Humanities and Religion; but also it is an origin of the cultural innovations of our so strange of globilisation. TIMAEUS, thus, can reveal Idealism as something more fundamental , more refined, more developed than is now accepted by the scientific community and the piblic. TIMAEUS has a significant cultural agenda, connected with the high orbital performance of the synthetic arts, combining a knowledge of the truly spiritual as well as the universal. In particular, classical ballet as a synthetic art can be a new and powerful perfector and re-creator of the real human, real idealistic, real complex culture in orbit. As is well known, Carlo Blasis, the most important dance theorist of the 19t h .century, made probably the first attempts to use the scientific ideas of Leonardo da Vinci and Isaac Newton for the understanding of the gravitational nature of balance and allegro in ballet. In particular Blasis's idea of the limited use of the legs in classical dance realised by the gifted pupils of Enrico Cecchetti - M.Fokine, A.Pavlova and V.Nijinsky, with thinkable purity and elegance of style. V.Nijinsky in his remarkable animation of the dance of two dimensional creatures of a Euclidean flat world (L'Apres Midi d'un Faune,1912) discovered that true classical dance has some gravitational limits. For example, Nijinsky's Faunes and Nymphs mut use running on the heels (In accordance with "Partitura" 1916); they cannot use a turn-out or epaulement for their pas-de-bra. In other words Nijinsky's dancers must live in weightlessness in order to perform what his "Partitura" (L'Apres Midi d'un Faune, version of 1916) describes. Diaghilev and Benois, platonised theorists of the Ballet Russe, suggested that the true idealised classical dance must be performed in Tiepolo's weightlessnessful manner of later Baroque. Anna Pavlova by her idiosyncrasy of parallel motion opened the New World of Aesthetics and brought it to its utmost perfection. Hence, it is natural to think that some findings of choreographers could be developed and tested in space environment. Moreover, we believe that classical ballet itself could be brought to perfection in space fter Diaghilev's reform. Correspondingly, we may await that such innovations can initiate a development of the New Grand Style in Arts, Music and Choreography free from contemporary religious and national prejudices.

Popov, M.

208

INVARIANT IDEALS AND POLYNOMIAL FORMS  

Microsoft Academic Search

Let K(H) denote the group algebra of an innite locally nite group H. In recent years, the lattice of ideals of K(H) has been extensively studied under the assumption that H is simple. From these many results, it appears that such group algebras tend to have very few ideals. While some work still remains to be done in the simple

D. S. PASSMAN

209

Carbon Nanomaterials: The Ideal Interconnect  

E-print Network

Carbon Nanomaterials: The Ideal Interconnect Technology for Next- Generation ICs Hong Li, Chuan Xu-generation ICs. In this research, carbon nanomaterials, with their many attractive properties, are emerging-a`-vis optical and RF interconnects, and we illustrate why carbon nanomaterials constitute the ideal intercon

210

On Fuzzy Ideals of BL-Algebras  

PubMed Central

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

Xin, Xiao Long

2014-01-01

211

Gas  

MedlinePLUS

... swallow and the breakdown of undigested food by bacteria in the large intestine. Certain foods may cause gas. Foods that produce gas in one person may not cause gas in another. You can reduce the amount of gas you have by Drinking lots of water and non-fizzy drinks Eating more slowly so ...

212

Quantum chaos in ultracold collisions of gas-phase erbium atoms.  

PubMed

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. PMID:24670766

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

2014-03-27

213

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

214

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

215

Characterization of Pb24Te76 quantum dot thin film synthesized by inert gas condensation  

NASA Astrophysics Data System (ADS)

Air-stable and thermal-stable lead telluride quantum dot was successfully prepared on glass substrate by inert gas condensation (IGC) method. Argon (Ar) is the inert gas used during deposition process with a constant flow rate of 3 × 10-3 Torr. The effect of heat-treatment process at different times was studies for structure, optical and electrical properties for nanocrystalline thin films. The structures of the as deposited and heat-treated films were investigated using grazing incident in-plane X-ray diffraction (GIIXD). The GIIXD pattern showed nanostructure face centered cubic structure of PbTe thin films. The energy dispersive X-ray analysis (EDX) of as deposited PbTe thin film was carried out and showed that the atomic ratio of Pb/Te was 24/76. The particle size of the as deposited PbTe film and after stored it in an unhumid atmosphere are 6.8 ± 0.3 nm and 7.2 ± 0.3 nm respectively as estimated form TEM image (i.e. in the same level of particle size). However, the particle size was changed to be 11.8 ± 0.3 nm after heat-treated for 5 h at 473 K. These particle size values of PbTe thin film are smaller than its Bohr radius. The estimated value of optical band gap Eg decreased from 1.71 eV for the as deposited film to 1.62 eV for film heat-treated (5 h at 473 K). The dc electrical conductivity is increased with raising temperature in the range (303-473 K) for all thin films under investigation. The deduced activation energy decreased from 0.222 eV for as deposited sample to 0.125 eV after heat-treated at 473 K for 5 h.

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

2015-01-01

216

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

E-print Network

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

217

Spherical Top-Hat Collapse of Viscous Modified Chaplygin Gas in Einstein's Gravity and Loop Quantum Cosmology  

E-print Network

In this work, we focus on the collapse of a spherically symmetric perturbation, with a classical top-hat profile, to study the nonlinear evolution of only viscous modified Chaplygin gas (VMCG) perturbations in Einstein's gravity as well as in loop quantum Cosmology (LQC). In the perturbed region, we have investigated the natures of equation of state parameter, square speed of sound and another perturbed quantities. The results have been analyzed by numerical and graphical investigations.

Ujjal Debnath; Mubasher Jamil

2015-01-03

218

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

219

All-optical production of a lithium quantum gas using narrow-line laser cooling  

SciTech Connect

We have used the narrow 2S{sub 1/2}{yields}3P{sub 3/2} transition in the ultraviolet (uv) to laser cool and magneto-optically trap (MOT) {sup 6}Li atoms. Laser cooling of lithium is usually performed on the 2S{sub 1/2}{yields}2P{sub 3/2} (D2) transition, and temperatures of {approx}300 {mu}K are typically achieved. The linewidth of the uv transition is seven times narrower than the D2 line, resulting in lower laser cooling temperatures. We demonstrate that a MOT operating on the uv transition reaches temperatures as low as 59 {mu}K. Furthermore, we find that the light shift of the uv transition in an optical dipole trap at 1070 nm is small and blueshifted, facilitating efficient loading from the uv MOT. Evaporative cooling of a two spin-state mixture of {sup 6}Li in the optical trap produces a quantum degenerate Fermi gas with 3x10{sup 6} atoms in a total cycle time of only 11 s.

Duarte, P. M.; Hart, R. A.; Hitchcock, J. M.; Corcovilos, T. A.; Yang, T.-L.; Reed, A.; Hulet, R. G. [Department of Physics and Astronomy and Rice Quantum Institute, Rice University, Houston, Texas 77005 (United States)

2011-12-15

220

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

SciTech Connect

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

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

2014-08-15

221

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

222

Majorization and arithmetic mean ideals  

E-print Network

Following "An infinite dimensional Schur-Horn theorem and majorization theory", Journal of Functional Analysis 259 (2010) 3115-3162, this paper further studies majorization for infinite sequences. It extends to the infinite case classical results on "intermediate sequences" for finite sequence majorization. These and other infinite majorization properties are then linked to notions of infinite convexity and invariance properties under various classes of substochastic matrices to characterize arithmetic mean closed operator ideals and arithmetic mean at infinity closed operator ideals.

Kaftal, V

2012-01-01

223

Constraining parameters of generalized cosmic Chaplygin gas in loop quantum cosmology  

NASA Astrophysics Data System (ADS)

We have assumed an FRW universe in a loop quantum cosmology (LQC) model, filled with dark matter and Generalized Cosmic Chaplygin gas (GCCG) dark energy, where dark matter follows a linear equation of state. We present the Hubble parameter in terms of the observable parameters ? m0 and H 0 with the redshift z and the other parameters like A, B, w m , ? and ? which coming from our model. From Stern data set (12 points) & SNe Type Ia 292 data (from Riess et al. in Astrophys. J. 607:665, 2004; Astrophys. J. 659:98, 2007; Astier et al. in Astron. Astrophys. 447:31, 2006) we have obtained the bounds of the arbitrary parameters by minimizing the ? 2 test. The best-fit values of the parameters are obtained by 66 %, 90 % and 99 % confidence levels. Next due to joint analysis with Stern + BAO and Stern + BAO + CMB observations, we have also obtained the bounds of the parameters ( A, B) by fixing some other parameters ?, w m and ?. From the best fit values of the parameters, we have obtained the distance modulus ?( z) for our theoretical GCCG model in LQC and from Supernovae Type Ia (Union2 sample 552 data from Amanullah et al. in Astrophys. J. 716:712, 2010 & Riess 292 data from Riess et al. in Astrophys. J. 607:665, 2004; Astrophys. J. 659:98, 2007; Astier et al. in Astron. Astrophys. 447:31, 2006), we have concluded that our model is in agreement with the Supernovae Type Ia sample data. In addition, we have investigated in details about the various types of Future Singularities that may be formed in this model and it is notable that our model is completely free from any types of future singularities.

Ranjit, Chayan; Debnath, Ujjal

2014-12-01

224

A comparison between entropies of aromatic compounds from quantum mechanical calculations and experiment  

Microsoft Academic Search

In this work, we perform a set of quantum mechanical and statistical mechanical calculations to generate the entropy of five simple, aromatic compounds—benzene, toluene, p-xylene, m-xylene and o-xylene—in the ideal gas state. We systematically examine how the choice of quantum mechanical level of theory and size of basis set impact the agreement between theory and experiment. Regardless of level of

Mohamad H. Kassaee; David J. Keffer; William V. Steele

2007-01-01

225

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

226

A stochastic approach to quantum statistics distributions: theoretical derivation and Monte Carlo modelling  

NASA Astrophysics Data System (ADS)

We present a method aimed at a stochastic derivation of the equilibrium distribution of a classical/quantum ideal gas in the framework of the canonical ensemble. The time evolution of these ideal systems is modelled as a series of transitions from one system microstate to another one and thermal equilibrium is reached via a random walk in the single-particle state space. We look at this dynamic process as a Markov chain satisfying the condition of detailed balance and propose a variant of the Monte Carlo Metropolis algorithm able to take into account indistinguishability of identical quantum particles. Simulations performed on different two-dimensional (2D) systems are revealed to be capable of reproducing the correct trends of the distribution functions and other thermodynamic properties. The simulations allow us to show that, away from the thermodynamic limit, a pseudo-Bose-Einstein condensation occurs for a 2D ideal gas of bosons.

Guastella, I.; Bellomonte, L.; Sperandeo-Mineo, R. M.

2009-02-01

227

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

228

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 and in the process learn about the subtleties of fluid mechanics and along the way see lots of interesting are generally incompressible--a feature essential to all modern car braking mechanisms. Fluids can be further

Malham, Simon J.A.

229

Transportation and Technology American Ideals  

E-print Network

1 East Transportation and Technology 2 East American Ideals 3 East American Wars and Politics ATM Level West Simulator Rides American PresidencyFirst Ladies Gunboat Philadelphia Price of Freedom Open American History and Culture GalleryWelcome Center Flag Hall Star-Spangled Banner Closed for Renovation

Mathis, Wayne N.

230

Convex analysis and ideal tensegrities  

NASA Astrophysics Data System (ADS)

A theoretical framework based on convex analysis is formulated and developed to study tensegrity structures under steady-state loads. Many classical results for ideal tensegrities are rationally deduced from subdifferentiable models in a novel mechanical perspective. Novel energy-based criteria for rigidity and pre-stressability are provided, allowing to formulate numerical algorithms for computations.

Maceri, Franco; Marino, Michele; Vairo, Giuseppe

2011-11-01

231

On time resolved gas temperature measurements in a pulsed dc plasma using quantum cascade laser absorption spectroscopy  

NASA Astrophysics Data System (ADS)

With a time resolution of 33 µs, the gas temperature in a pulsed dc air plasma admixed with 0.8% NO has been measured by quantum cascade laser absorption spectroscopy (QCLAS). For this purpose, the temperature dependent intensity ratios of two absorption structures of NO at 1900 cm-1 (5.26 µm) have been used. The QCLAS system worked in the Intra Pulse Mode with a pulse repetition frequency of 30 kHz leading to a spectrum recorded each 33 µs. In a low pressure discharge, the influence of nonlinear absorption phenomena causing strong distorted absorption structures of NO has been taken into account by a calibration routine based on tabulated line strengths. Different mean plasma currents have been applied to the discharge leading to gas temperature values ranging from about 300 K up to about 500 K.

Hübner, M.; Marinov, D.; Guaitella, O.; Rousseau, A.; Röpcke, J.

2012-11-01

232

Fuzzy k-ideals of semirings  

Microsoft Academic Search

The aim of this paper is to introduce the notions of fuzzy k-ideals, prime fuzzy k-ideals and semiregularity of semirings and to characterize prime fuzzy k-ideals, semiregular semirings, Noetherian semirings and Artinian semirings by fuzzy k-ideals

Shamik Ghosh

1998-01-01

233

Intutionistic Fuzzy Ideals in {\\Gamma}-semiring  

E-print Network

In this paper we have studied the relation between the intutionistic fuzzy left (respectively right) ideals of {\\Gamma}-semiring and that of operator semiring. Thereafter, we have established that the Lattices of all intutionistic fuzzy left (respectively right) ideal of {\\Gamma}-semiring is equivalent to that of Left operator semiring. We proved that Then there exist an inclusion preserving bijection ({\\mu}_{A,}\\u{psion}_{A})$\\rightarrow$({\\mu}_{B}^{+'},\\u{psion}_{B}^{+'}) between the lattices of all intuitionistic fuzzy right ideals (respectively intuitionistic fuzzy ideals) of S and the lattices of all intuitionistic fuzzy right ideals (respectively intuitionistic fuzzy ideals) of L. Where ({\\mu}_{A},\\u{psion}_{A}) is an intuitionistic fuzzy right (respectively intuitionistic fuzzy ideals) ideal of S. Also we have established few properties relating the k-ideals and h-ideals of {\\Gamma}-semiring with that of operator semiring.

Mehmood, Nayyar

2010-01-01

234

Ideals of polynomial semirings in tropical mathematics  

E-print Network

We describe the ideals, especially the prime ideals, of semirings of polynomials over layered domains, and in particular over supertropical domains. Since there are so many of them, special attention is paid to the ideals arising from layered varieties, for which we prove that every prime ideal is a consequence of finitely many binomials. We also obtain layered tropical versions of the classical Principal Ideal Theorem and Hilbert Basis Theorem.

Izhakian, Zur

2011-01-01

235

Quantum coherence in the dynamical excitation, ionization, and decaying of neon gas induced by X-ray laser  

E-print Network

We develop a large scale quantum master equation approach to describe dynamical processes of practical open quantum systems driven by both coherent and stochastic interactions by including more than one thousand true states of the systems, motivated by the development of highly bright and fully coherent lasers in the X-ray wavelength regime. The method combines the processes of coherent dynamics induced by the X-ray laser and incoherent relaxations due to spontaneous emissions, Auger decays, and electronic collisions. As examples, theoretical investigation of {\\it real} coherent dynamics of inner-shell electrons of a neon gas, irradiated by a high-intensity X-ray laser with a full temporal coherence, is carried out with the approach. In contrast to the rate equation treatment, we find that coherence can suppress the multiphoton absorptions of a neon gas in the ultra-intense X-ray pulse, due to coherence-induced Rabi oscillations and power broadening effects. We study the influence of coherence on ionization p...

Li, Yongqiang; Dong, Wenpu; Zeng, Jiaolong; Yuan, Jianmin

2015-01-01

236

Optical properties of very thin GaInAs(P)\\/InP quantum wells grown by gas source molecular beam epitaxy  

Microsoft Academic Search

Single quantum wells of GaInAs and GaInAsP isolated by 150-A?-thick InP barriers have been grown by gas source molecular beam epitaxy. The quantum wells ranged in thickness from 5 to 30 A?. Photoluminescence and transmission electron microscopy were used to characterize them. Intense luminescence was observed at low temperature even from the thinnest of the wells. The spectral shifts due

M. B. Panish; H. Temkin; R. A. Hamm; S. N. G. Chu

1986-01-01

237

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

238

Non-equilibrium dynamics of an ultracold Bose gas under a multi-pulsed quantum quench in interaction  

E-print Network

We investigate the nonequilibrium dynamical properties of a weakly-interacting Bose gas at zero temperature under the multi-pulsed quantum quench in interaction by calculating one-body, two-body correlation functions and Tan's contact of the model system. The multi-pulsed quench is represented as follows: first suddenly quenching the interatomic interaction from $g_{i}$ to $g_{f}$ at time $t=0$, holding time $t$, and then suddenly quenching interaction from $g_{f}$ back to $g_{i}$, holding the time $t$ sequence $n$ times. In particular, two typical kinds of quenching parameters are chosen, corresponding to $(g_{i}/g_{f}>1)$ and $(g_{i}/g_{f}pulsed QQ is more powerful way of studying the non-equilibrium dynamics of many-body quantum system than the `one-off' quantum quench. Finally, we discuss the ultra-short-range properties of the two-body correlation function after the $n$th quenching, which can be used to probe the `Tan'scontact' in experiments. All our calculations can be tested in current cold atom experiments.

Lei Chen; Zhidong Zhang; Zhaoxin Liang

2015-01-28

239

An idealized model of homogeneous solid propellant combustion  

NASA Technical Reports Server (NTRS)

The idealization of solid propellant combustion which consists of a single condensed-phase reaction and a single gas-phase reaction is discussed. A limiting-case solution to the gas-phase conservation equations is developed and tested by comparison with transformed thermocouple data. Closed-form expressions are derived for the burning rate and temperature sensitivity. Both quantities are linked explicitly to the solid and gas activation energies. It is concluded that the combustion phenomenology associated with the above idealization is still not fully understood. It is suggested that a careful study of the various limiting-case solutions tempered by a small set of numerical benchmark calculations might further such understanding.

Miller, M. S.

1980-01-01

240

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

241

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

242

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

SciTech Connect

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

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

2007-08-15

243

Reflexive ideals in Iwasawa algebras  

Microsoft Academic Search

Let G be a torsionfree compact p-adic analytic group. We give sufficient conditions on p and G which ensure that the Iwasawa algebra ?G of G has no non-trivial two-sided reflexive ideals. Consequently, these conditions imply that every non-zero normal element in ?G is a unit. We show that these conditions hold in the case when G is an open

Konstantin Ardakov; Feng Wei; James J. Zhang

2008-01-01

244

Experimentally efficient methods for estimating the performance of quantum measurements  

E-print Network

Efficient methods for characterizing the performance of quantum measurements are important in the experimental quantum sciences. Ideally, one requires both a physically relevant distinguishability measure between measurement ...

Magesan, Easwar

245

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

246

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

E-print Network

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

Bahrami, Majid

247

Quantum-relativistic hydrodynamic model for a spin-polarized electron gas interacting with light.  

PubMed

We develop a semirelativistic quantum fluid theory based on the expansion of the Dirac Hamiltonian to second order in 1/c. By making use of the Madelung representation of the wave function, we derive a set of hydrodynamic equations that comprises a continuity equation, an Euler equation for the mean velocity, and an evolution equation for the electron spin density. This hydrodynamic model is then applied to study the dynamics of a dense and weakly relativistic electron plasma. In particular, we investigate the impact of the quantum-relativistic spin effects on the Faraday rotation in a one-dimensional plasma slab irradiated by an x-ray laser source. PMID:25122397

Morandi, Omar; Zamanian, Jens; Manfredi, Giovanni; Hervieux, Paul-Antoine

2014-07-01

248

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

249

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

250

Homological Invariants of Monomial and Binomial Ideals  

E-print Network

In this dissertation, we study numerical invariants of minimal graded free resolutions of homogeneous ideals in a polynomial ring R. Chapters 2, 3 and 4 deal with homological invariants of edge ideals of bipartite graphs. First, in Chapter 2, we...

Kummini, Neelakandhan Manoj

2008-08-19

251

Quantum cascade laser investigations of CH4 and C2H2 interconversion in hydrocarbon/H2 gas mixtures during microwave plasma  

E-print Network

Quantum cascade laser investigations of CH4 and C2H2 interconversion in hydrocarbon/H2 gas mixtures during microwave plasma enhanced chemical vapor deposition of diamond Jie Ma,1 Andrew Cheesman,1 Michael for plasma enhanced diamond chemical vapor deposition CVD have been investigated by line-of-sight infrared

Bristol, University of

252

Fuzzy ideals in $\\Gamma-$semiring  

E-print Network

In this paper we have studied the relation between the fuzzy left (respectively right) ideals of $\\Gamma-$semiring and that of operator semiring. Thereafter, we have established that the Lattices of all fuzzy left (respectively right) ideal of $\\Gamma-$semiring is equivalent to that of Left operator semiring. Also we have established few properties relating the $k-$ideals and $h-$ideals of $\\Gamma-$semiring with that of operator semiring.

Ghosh, Jayanta

2010-01-01

253

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

254

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

255

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

256

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

257

January 2, 22, 28, 2012 Infinite Idealizations  

E-print Network

1 January 2, 22, 28, 2012 Infinite Idealizations John D. Norton1 Department of History and idealization (Norton, forthcoming). A goal 1 I thank Jos Uffink for helpful discussion. #12;2 of that work described as idealizations. This literature examines the behavior of systems composed of very many

258

Quantum chemical study and infrared spectroscopy of hydrogen-bonded CHCl3-NH3 in the gas phase  

NASA Astrophysics Data System (ADS)

Molecular association of chloroform with ammonia is studied by high-level quantum chemical calculations including correlated MP2 and CCSD(T) calculations with basis sets up to6-311++G(d,p) and counterpoise corrected energies, geometries, and frequencies. The calculations predict an eclipsed hydrogen-bonded complex of C3v symmetry (?E0=-15.07kJmol-1) with 225.4pm intermolecular CH⋯N distance. Intermolecular interactions are analysed by Kitaura-Morokuma [Int. J. Quantum Chem. 10, 325 (1976)] interaction energy decomposition. Compared to the monomer, the C-H bond is elongated, and the CH-stretching fundamental shifts to lower wave numbers and has a marked ˜340-fold increase of its intensity. Based on these predictions, the complex is observed by infrared spectroscopy in the gas phase at room temperature. A subtraction procedure isolates its spectrum, and a dilution series confirms the presence of a 1:1 complex. The CHCl3⋯NH3 complex has an experimental -17.5cm-1 shift of its CH-stretching vibration, and CDCl3⋯NH3 a -12.5cm-1 shift of the CD-stretching vibration. After a deperturbation of the CH-stretching/bending mode Fermi resonance system, this indicates a "redshifting" or more appropriately, a "C-H elongating" hydrogen bond in agreement with the ab initio calculations. An estimate of the complex concentration gives the equilibrium constant Kp=0.024 (p?=105Pa ) at 295K for the dimerization, providing one of the few examples where a hydrogen-bonded gas phase complex at room temperature could be quantitatively studied by infrared spectroscopy.

Hippler, Michael

2007-08-01

259

Quantum Boltzmann equation for a mobile impurity in a degenerate Tonks-Girardeau gas  

NASA Astrophysics Data System (ADS)

We investigate the large-time asymptotical behavior of a mobile impurity immersed in a degenerate Tonks-Girardeau gas. We derive a correct weak-coupling kinetic equation valid for N arbitrary ratio of masses of gas and impurity particles. When gas particles are either lighter or heavier than the impurity we find that our theory is equivalent to the Boltzmann theory with the collision integral calculated via the Fermi Golden Rule. On the contrary, in the equal-mass case, Fermi Golden Rule treatment gives false results due to not accounting for multiple coherent scattering events. The latter are treated by the resummation of ladder diagrams, which leads to a new kinetic equation. The asymptotic momentum of the impurity produced from this equation coincides with the result obtained by means of the Bethe ansatz.

Gamayun, O.

2014-06-01

260

Perpetual motion of a mobile impurity in a one-dimensional quantum gas  

E-print Network

Consider an impurity particle injected in a degenerate one-dimensional gas of noninteracting fermions (or, equivalently, Tonks-Girardeau bosons) with some initial momentum $p_0$. We examine the infinite-time value of the momentum of the impurity, $p_\\infty$, as a function of $p_0$. A lower bound on $|p_\\infty(p_0)|$ is derived under fairly general conditions. The derivation, based on the existence of the lower edge of the spectrum of the host gas, does not resort to any approximations. The existence of such bound implies the perpetual motion of an impurity in a one-dimensional gas of noninteracting fermions or Tonks-Girardeau bosons at zero temperature. The bound has an especially simple and useful form when the interaction between the impurity and host particles is everywhere repulsive.

Oleg Lychkovskiy

2014-03-04

261

Growth initiation for buried-heterostructure quantum-cascade laser regrowth by gas-source molecular-beam epitaxy  

NASA Astrophysics Data System (ADS)

We describe an optimized growth sequence for the overgrowth of quantum cascade laser ridge sidewalls with semi-insulating InP:Fe. A thin In0.52Al0.48As spacer layer grown on the laser ridge sidewalls before InP:Fe prevents the formation of void defects at this interface, which appear otherwise. Elimination of these voids at the sidewalls has led to more than a two-fold improvement of the thermal conductivity in a 7 ?m wide buried-heterostructure quantum-cascade laser overgrown with InP:Fe by gas-source molecular-beam epitaxy, and has allowed the continuous-wave operation of the laser up to 210 K. The measured thermal conductance is Gth=500 W/K cm2 at 210 K and Gth=1020 W/K cm2 at 127 K, comparable to the state of the art literature values obtained with regrowth by metal-organic vapor-phase epitaxy.

Flores, Y. V.; Elagin, M.; Kurlov, S. S.; Aleksandrova, A.; Monastyrskyi, G.; Kischkat, J.; Semtsiv, M. P.; Masselink, W. T.

2014-07-01

262

The molecular structure of niobium pentachloride by quantum chemical calculations and gas electron diffraction  

NASA Astrophysics Data System (ADS)

The molecular structure of NbCl 5 was determined experimentally by gas electron diffraction and computationally by structure optimisation of D 3h models. The bond distances obtained by ab initio calculations with very large basis sets, relativistic effects included through the one-electron Douglas-Kroll method and all electrons correlated at the MP2 level and by gas electron diffraction are: (calc/exp) Nb-Cl ax=230.7/230.6(5) pm and Nb-Cl eq=227.0/227.5(4) pm.

Gove, S. K.; Gropen, O.; Fægri, K.; Haaland, A.; Martinsen, K.-G.; Strand, T. G.; Volden, H. V.; Swang, O.

1999-08-01

263

Statistical mechanics based on fractional classical and quantum mechanics  

SciTech Connect

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

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

2014-03-15

264

Modules over principal ideal rings  

E-print Network

(ni)x)) + ri(ri)xj)] 'I ~ I )cl q. rqix) + (r~r~)) i j= ( g [(n r ) + (r r )] x ig=l DEFINITION 2. 8. If M is a unitary R-module with a finite set of generators X such that every y c M can be wr1. tten in one and only one way using the elements of X...) as ra + na = ra + nla = (r + nl)a = r'a where r' c R, and thus (a) in this ease consists of all ordi- nary ring multiples ra. DEFINITION 1. 2 ~ The ideal (a) generated by an element a a R i8 e lied a ~i*1. 1 f. d al. We shall now consider two...

Vieaux, Jules Bellin

2012-06-07

265

Quantum Monte Carlo study of the dynamic structure factor in the gas and crystal phase of hard-sphere bosons  

NASA Astrophysics Data System (ADS)

We investigate the dynamic structure factor of a system of Bose particles at zero temperature using quantum Monte Carlo methods. Interactions are modeled using a hard-sphere potential of size a and simulations are performed for values of the gas parameter na3 ranging from the dilute regime up to densities n where the thermodynamically stable phase is a solid. With increasing density, we observe a crossover of the dispersion of elementary excitations from a Bogoliubov-type spectrum to a phonon-maxon-roton curve and the emergence of a broad multiphonon contribution accompanying the single-quasiparticle peak. In particular, for na3=0.2138, which corresponds to superfluid 4He at equilibrium density, the extracted spectrum turns out to be in good agreement with the experimental energy-momentum dispersion relation in the roton region and for higher momenta. The behavior of the spectral function at the same density in the stable solid and metastable gas phase above the freezing point is also discussed.

Rota, R.; Tramonto, F.; Galli, D. E.; Giorgini, S.

2013-12-01

266

A model with a precipitous ideal, but no normal precipitous ideal.  

E-print Network

A model with a precipitous ideal, but no normal precipitous ideal. Moti Gitik December 4, 2012 with a precipitous ideal on 1 but without normal precipitous ideals. This answers a question by T. Jech and K. Prikry. In the constructed model there are no Q­point precipitous filters on 1, i.e. those isomorphic to extensions of Cub1

Gitik, Moti

267

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

268

Nonlocal Exchange-Correlation Potential for Inhomogeneous Electron Gas and Quantum Fluids  

Microsoft Academic Search

An exact but formal expression for the exchange-correlation potential muxc(r|n) for an inhomogeneous electron gas at arbitrary temperature is obtained in terms of the quantal direct correlation function (DCF) of the inhomogeneous system. By introducing the effective local density n*(r) and approximating it by the functional Taylor's series around a suitable density to first order, approximate exchange-correlation potentials are derived

Junzo Chihara

1978-01-01

269

A quantum Monte Carlo investigation of exchange and correlation of the inhomogeneous electron gas  

Microsoft Academic Search

The exchange-correlation (XC) energy functional, E_xc, plays a fundamental role in the density functional theory of solids. Using an adiabatic connection procedure, E_xc can be expressed in terms of the non-local exchange-correlation hole surrounding each electron. We devised a new method for sampling the exchange-correlation hole of the inhomogeneous electron gas which is based on combining the above adiabatic connection

Maziar Nekovee; W. M. C. Foulkes; A. J. Williamson; G. Rajagopal; R. J. Needs

1997-01-01

270

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

271

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

272

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

NASA Astrophysics Data System (ADS)

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

Cheng, Xiaolu; Cina, Jeffrey A.

2014-07-01

273

An implicit algorithm for the ideal MHD equations  

SciTech Connect

The authors are developing a new implicit algorithm for solving the ideal MHD equations. The algorithm is based upon the lower-upper symmetric-Gauss-Seidel method which was originally developed for solving the Euler and Navier-Stokes equations of gas dynamics. In the authors method, the ideal MHD equations are solved as a coupled set of hyperbolic equations. The flux terms are split according to the positive and negative eigenvalues of the flux Jacobians so that the implicit operator can be approximately factored into lower and upper triangular matrices. This splitting eliminates the need to invert block diagonal matrices and thus is more efficient than other implicit methods based on approximate factorizations. The authors have incorporated this algorithm into a finite-volume code for solving the axisymmetric ideal MHD equations. Results are shown for code validation runs on simple geometries and compared with results form a typical explicit algorithm. In the future the authors plan to extend this algorithm to solve the full three-dimensional, non-ideal MHD equations.

Jones, O.S.; Eberhardt, D.S. [Univ. of Washington, Seattle, WA (United States)

1994-12-31

274

Finite Temperature Quantum Effects in Many-body Systems by Classical Methods  

E-print Network

A recent description of an exact map for the equilibrium structure and thermodynamics of a quantum system onto a corresponding classical system is summarized. Approximate implementations are constructed by pinning exact limits (ideal gas, weak coupling), and illustrated by calculation of pair correlations for the uniform electron gas and shell structure for harmonically confined charges. A wide range of temperatures and densities are addressed in each case. For the electron gas, comparisons are made to recent path integral Monte Carlo simulations (PIMC) showing good agreement. Finally, the relevance for orbital free density functional theory for conditions of warm, dense matter is discussed briefly.

Wrighton, Jeffrey; Dutta, Sandipan

2015-01-01

275

Pharmacytes: an ideal vehicle for targeted drug delivery.  

PubMed

An ideal nanotechnology-based drug delivery system is a pharmacyte--a self-powered, computer-controlled medical nanorobot system capable of digitally precise transport, timing, and targeted delivery of pharmaceutical agents to specific cellular and intracellular destinations within the human body. Pharmacytes may be constructed using future molecular manufacturing technologies such as diamond mechanosynthesis which are currently being investigated theoretically using quantum ab initio and density-functional computational methods. Pharmacytes will have many applications in nanomedicine such as initiation of apoptosis in cancer cells and direct control of cell signaling processes. PMID:17048481

Freitas, Robert A

2006-01-01

276

Stability of gas-phase tartaric acid anions investigated by quantum chemistry, mass spectrometry, and infrared spectroscopy.  

PubMed

In an effort to understand the chemical factors that stabilize dianions, experimental and theoretical studies on the stability of the tartrate dianion were performed. Quantum chemical calculations at the coupled cluster level reveal only a metastable state with a possible decomposition pathway (O(2)C-CH(OH)-CH(OH)-CO(2))(2-) ? (O(2)C-CH(OH)-CH(OH))(•-) + CO(2) + e(-) explaining the observed gas-phase instability of this dianion. Further theoretical data were collected for the bare dianion, this molecule complexed to water, sodium, and a proton, in both the meso and l forms as well as for the uncomplexed radical anion and neutral diradical. The calculations suggest that the l-tartrate dianion is more thermodynamically stable than the dianion of the meso stereoisomer and that either dianion can be further stabilized by association with a separate species that can help to balance the charge of the molecular complex. Mass spectrometry was then used to measure the energy needed to initiate collisionally induced dissociation of the racemic tartrate dianion and for the proton and sodium adducts of both the racemic and meso form of this molecule. Infrared action spectra of the dianion stereoisomers complexed with sodium were also acquired to determine the influence of the metal ion on the vibrations of the dianions and validate the computationally predicted structures. These experimental data support the theoretical conclusions and highlight the instability of the bare tartrate dianion. From the experimental work, it could also be concluded that the pathway leading to dissociation is under kinetic control because the sodium adduct of the racemic stereoisomer dissociated at lower collisional energy, although it was calculated to be more stable, and that decomposition proceeded via C-C bond dissociation as computationally predicted. Taken together, these data provide insight into the gas-phase stability of the tartrate dianion and highlight the role of adducts in stabilizing this species. PMID:22486160

Tonner, Ralf; Schwerdtfeger, Peter; May, Amanda L; Steill, Jeffrey D; Berden, Giel; Oomens, Jos; Campagna, Shawn R; Compton, Robert N

2012-05-17

277

Quantum oscillations and subband properties of the two-dimensional electron gas at the LaAlO3/SrTiO3 interface  

NASA Astrophysics Data System (ADS)

We have performed high field magnetotransport measurements to investigate the interface electron gas in a high mobility SrTiO3/SrCuO2/LaAlO3/SrTiO3 heterostructure. Shubnikov-de Haas oscillations reveal several 2D conduction subbands with carrier effective masses of 0.9me and 2me, quantum mobilities of order 2000 cm2/V s, and band edges only a few millielectronvolts below the Fermi energy. Measurements in tilted magnetic fields confirm the 2D character of the electron gas, and show evidence of inter-subband scattering.

McCollam, A.; Wenderich, S.; Kruize, M. K.; Guduru, V. K.; Molegraaf, H. J. A.; Huijben, M.; Koster, G.; Blank, D. H. A.; Rijnders, G.; Brinkman, A.; Hilgenkamp, H.; Zeitler, U.; Maan, J. C.

2014-02-01

278

Quantum gases. Critical dynamics of spontaneous symmetry breaking in a homogeneous Bose gas.  

PubMed

Kibble-Zurek theory models the dynamics of spontaneous symmetry breaking, which plays an important role in a wide variety of physical contexts, ranging from cosmology to superconductors. We explored these dynamics in a homogeneous system by thermally quenching an atomic gas with short-range interactions through the Bose-Einstein phase transition. Using homodyne matter-wave interferometry to measure first-order correlation functions, we verified the central quantitative prediction of the Kibble-Zurek theory, namely the homogeneous-system power-law scaling of the coherence length with the quench rate. Moreover, we directly confirmed its underlying hypothesis, the freezing of the correlation length near the transition. Our measurements agree with a beyond-mean-field theory and support the expectation that the dynamical critical exponent for this universality class is z = 3/2. PMID:25574021

Navon, Nir; Gaunt, Alexander L; Smith, Robert P; Hadzibabic, Zoran

2015-01-01

279

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

2012-12-05

280

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

281

Spectroscopic trace-gas sensor with rapidly scanned wavelengths of a pulsed quantum cascade laser for in situ NO monitoring of industrial exhaust systems  

Microsoft Academic Search

Development of a pulsed quantum cascade laser (QCL)-based spectroscopic trace-gas sensor for sub-part-per-million detection of nitric oxide (NO) and capable of monitoring other molecular species such as CO2, H2O, and NH3 in industrial combustion exhaust systems is reported. Rapid frequency modulation is applied to the QCL to minimize the influence of fluctuating non-selective absorption. A novel method utilizes only a

G. Wysocki; A. A. Kosterev; F. K. Tittel

2005-01-01

282

Solvothermal, chloroalkoxide-based synthesis of monoclinic WO(3) 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

283

A trace methane gas sensor using mid-infrared quantum cascaded laser at 7.5 ?m  

NASA Astrophysics Data System (ADS)

Presented is a compact instrument developed for in situ high-stable and sensitive continuous measurement of trace gases in air, with results shown for ambient methane (CH4) concentration. This instrument takes advantage of recent technology in thermoelectrically cooled pulsed Fabry-Perot (FP) quantum cascaded (QC) laser driving in a pulse mode operating at 7.5 ?m to monitor a well-isolated spectral line near the ?4 fundamental band of CH4. A high-quality liquid nitrogen cooled mercury cadmium telluride mid-infrared detector with time discriminating electronics is used along with a total reflection coated gold ellipsoid mirror offering 20 cm single pass optical absorption in an open-path cell to achieve stability of 5.2 × 10-3 under experimental condition of 200 ppm measured ambient CH4. The instrument operates continuously, and integrated software for laser control using direct absorption provides quantitative trace gas measurements without calibration. One may substitute a QC laser operating at a different wavelength to measure other gases. The instrument can be applied to field measurements of gases of environmental concern.

Chen, Chen; Newcomb, Robert W.; Wang, Yiding

2013-12-01

284

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

285

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

286

Gas Phase Photoacoustic Sensor at 8.41 mu m Using Quartz Tuning Forks and Amplitude Modulated Quantum Cascade Lasers  

SciTech Connect

We demonstrate the performance of a novel long-wave infrared photoacoustic laser absorbance spectrometer for gas-phase species using an amplitude modulated (AM) quantum cascade (QC) laser and a quartz tuning fork microphone. Photoacoustic signal was generated by focusing the output of a Fabry-Perot QC laser operating at 8.41 ?m between the legs of a quartz tuning fork which served as a transducer for the transient acoustic pressure wave. The QC laser was modulated at the resonant frequency of the tuning fork (32.8 kHz) and delivered a modest 5.3 mW at the tuning fork. This spectrometer was calibrated using the infrared absorber Freon-134a by performing a simultaneous absorption measurement using a 35 cm absorption cell. The NEAS of this instrument was determined to be 2 x 10{sup -8} W cm-1 Hz{sup -1/2}. A corresponding theoretical analysis of the instrument sensitivity is presented and is capable of quantitatively reproducing the experimental NEAS, indicating that the fundamental sensitivity of this technique is limited by the noise floor of the tuning fork itself.

Wojcik, Michael D.; Phillips, Mark C.; Cannon, Bret D.; Taubman, Matthew S.

2006-10-01

287

Quad quantum cascade laser spectrometer with dual gas cells for the simultaneous analysis of mainstream and sidestream cigarette smoke  

NASA Astrophysics Data System (ADS)

A compact, fast response, infrared spectrometer using four pulsed quantum cascade (QC) lasers has been applied to the analysis of gases in mainstream (MS) and sidestream (SS) cigarette smoke. QC lasers have many advantages over the traditional lead-salt tunable diode lasers, including near room temperature operation with thermoelectric cooling and single mode operation with improved long-term stability. The new instrument uses two 36 m, 0.3 l multiple pass absorption gas cells to obtain a time response of 0.1 s for the MS smoke system and 0.4 s for the SS smoke system. The concentrations of ammonia, ethylene, nitric oxide, and carbon dioxide for three different reference cigarettes were measured simultaneously in MS and SS smoke. A data rate of 20 Hz provides sufficient resolution to determine the concentration profiles during each 2 s puff in the MS smoke. Concentration profiles before, during and after the puffs also have been observed for these smoke constituents in SS smoke. Also, simultaneous measurements of CO 2 from a non-dispersive infrared (NDIR) analyzer are obtained for both MS and SS smoke. In addition, during this work, nitrous oxide was detected in both the MS and SS smoke for all reference cigarettes studied.

Baren, Randall E.; Parrish, Milton E.; Shafer, Kenneth H.; Harward, Charles N.; Shi, Quan; Nelson, David D.; McManus, J. Barry; Zahniser, Mark S.

2004-12-01

288

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

PubMed

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

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

2012-11-01

289

Ideal objects in set Oliver Kullmann  

E-print Network

Ideal objects in set theory and topology Oliver Kullmann Historical remarks Enumerating sets and topology Oliver Kullmann Computer Science Department Swansea University MRes Seminar Swansea, November 17, 2008 #12;Ideal objects in set theory and topology Oliver Kullmann Historical remarks Enumerating sets

Berger, Ulrich

290

Ideal Clutters G erard Cornu ejols  

E-print Network

Ideal Clutters G#19;erard Cornu#19;ejols #3; and Bertrand Guenin y July 1999, revised September. In this tutorial, we present the state of the art and open problems on this question. Keywords: Ideal clutter Introduction A clutter C is a family E(C) of subsets of a #12;nite ground set V (C) with the property that A 1

Cornuejols, Gerard P.

291

Ideals with bases of unbounded Borel hierarchy  

Microsoft Academic Search

We present several naturally defined ideals which have a Borel base but, unlike the classical examples of such ideals, not of bounded Borel complexity. We inves- tigate its basic properties. We show that they have property (M) and we compute some of their cardinal coefficients.

Piotr Borodulin-Nadzieja

292

Application of a Quantum Cascade Laser for Time-Resolved, in Situ Probing of CH4/H2 and C2H2/H2 Gas Mixtures during Microwave Plasma Enhanced Chemical Vapor  

E-print Network

Application of a Quantum Cascade Laser for Time-Resolved, in Situ Probing of CH4/H2 and C2H2/H2 Gas 10, 2006 First illustrations of the utility of pulsed quantum cascade lasers for in situ probing on such issues span optical emission spectroscopy, in situ mass spectrometry,4,5 and a number of laser

Bristol, University of

293

A quantum mechanical model of interference  

Microsoft Academic Search

In this paper an ideal quantum mechanical model of interference is constructed, in particular, the role of the quantum mechanical phase difference of two harmonic modes on the interference picture is investigated.

A. Shalom; J. Zak

1973-01-01

294

Ideal regularization for learning kernels from labels.  

PubMed

In this paper, we propose a new form of regularization that is able to utilize the label information of a data set for learning kernels. The proposed regularization, referred to as ideal regularization, is a linear function of the kernel matrix to be learned. The ideal regularization allows us to develop efficient algorithms to exploit labels. Three applications of the ideal regularization are considered. Firstly, we use the ideal regularization to incorporate the labels into a standard kernel, making the resulting kernel more appropriate for learning tasks. Next, we employ the ideal regularization to learn a data-dependent kernel matrix from an initial kernel matrix (which contains prior similarity information, geometric structures, and labels of the data). Finally, we incorporate the ideal regularization to some state-of-the-art kernel learning problems. With this regularization, these learning problems can be formulated as simpler ones which permit more efficient solvers. Empirical results show that the ideal regularization exploits the labels effectively and efficiently. PMID:24824969

Pan, Binbin; Lai, Jianhuang; Shen, Lixin

2014-08-01

295

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

296

Quantum memory Quantum memory  

NASA Astrophysics Data System (ADS)

Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The quest for higher efficiency, better fidelity, broader bandwidth, multimode capacity and longer storage lifetime is pursued in all those approaches, as shown in this special issue. The improvement of quantum memory operation specifically requires in-depth study and control of numerous physical processes leading to atomic decoherence. The present issue reflects the development of rare earth ion doped matrices offering long lifetime superposition states, either as bulk crystals or as optical waveguides. The need for quantum sources and high efficiency detectors at the single photon level is also illustrated. Several papers address the networking of quantum memories either in long-haul cryptography or in the prospect of quantum processing. In this context, much attention has been paid recently to interfacing quantum light with superconducting qubits and with nitrogen-vacancy centers in diamond. Finally, the quantum interfacing of light with matter raises questions on entanglement. The last two papers are devoted to the generation of entanglement by dissipative processes. It is shown that long lifetime entanglement may be built in this way. We hope this special issue will help readers to become familiar with the exciting field of ensemble-based quantum memories and will stimulate them to bring deeper insights and new ideas to this area.

Le Gouët, Jean-Louis; Moiseev, Sergey

2012-06-01

297

Closure Operations on Ideals Sara Faridi  

E-print Network

Closure Operations on Ideals by Sara Faridi A dissertation submitted in partial ful#12;llment Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 Integral Closure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Integral Closure of Graded Rings and Rees Rings . . . . . . . . . . . . . . . 8 2.3 Tight

Faridi, Sara

298

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

299

NEW CLASSES OF IDEALS IN SUBTRACTION ALGEBRAS  

E-print Network

In [4] B. M. Schein considered systems of the form ( ; o; n),where is a set of functions closed under the composition "o " of functions (and hence ( ; o) is a function semigroup) and the set theoretic subtraction "n " (and hence is a subtraction algebra in the sense of [1]). He proved that every subtraction semigroup is isomorphic to a di erence semigroup of invertible functions. B. Zelinka [5] discussed a problem proposed by B. M. Schein concerning the structure of multiplication in a subtraction semigroup. He solved the problem for subtraction algebras of a special type, called the atomic subtraction algebras. A particular attention was paid to the ideals of a subtraction algebra (cf. [2, 3] and papers cited there). Prime ideals play a central role in the theory of subtraction algebras. Of course, a prime ideal P of a subtraction algebra X is a proper ideal of X with the property

Ahmad Yousefian Darani; Young Bae Jun; Kyung Ho Kim; Eun Hwan Roh; Kyung Ho Kim; Jong Geol Lee; On Prime

300

When every principal ideal is flat  

E-print Network

This paper deals with well-known notion of $PF$-rings, that is, rings in which principal ideals are flat. We give a new characterization of $PF$-rings. Also, we provide a necessary and sufficient condition for $R\\bowtie I$ (resp., $R/I$ when $R$ is a Dedekind domain or $I$ is a primary ideal) to be $PF$-ring. The article includes a brief discussion of the scope and precision of our results.

Cheniour, Fatima

2010-01-01

301

When every principal ideal is flat  

Microsoft Academic Search

This paper deals with well-known notion of $PF$-rings, that is, rings in which principal ideals are flat. We give a new characterization of $PF$-rings. Also, we provide a necessary and sufficient condition for $R\\\\bowtie I$ (resp., $R\\/I$ when $R$ is a Dedekind domain or $I$ is a primary ideal) to be $PF$-ring. The article includes a brief discussion of the

Fatima Cheniour; Najib Mahdou

2010-01-01

302

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

303

Efficient channels for the ideal observer  

NASA Astrophysics Data System (ADS)

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

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

2004-05-01

304

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 {delta}B-vector={nabla} Multiplication-Sign ({xi}-vector Multiplication-Sign B-vector), however, perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories, the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement {xi}-vector are derived which preserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

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

2013-04-15

305

Transport properties of the two-dimensional electron gas in wide AlP quantum wells including temperature and correlation effects  

NASA Astrophysics Data System (ADS)

We investigate the mobility, magnetoresistance and scattering time of a quasi-two-dimensional electron gas in a GaP/AlP/GaP quantum well of width L>Lc=45.7 Å at zero and finite temperatures. We consider the interface-roughness and impurity scattering, and study the dependence of the mobility, the resistance and scattering time ratio on the carrier density and quantum well width for different values of the impurity position and temperature using different approximations for the local-field correction. In the case of zero temperature and Hubbard local-field correction our results reduce to those of Gold and Marty (Phys. Rev. B. 76 (2007) 165309) [3]. We also study the correlation and multiple scattering effects on the total mobility and the critical density for a metal-insulator transition.

Tai, Vo Van; Khanh, Nguyen Quoc

2015-03-01

306

High-Resolution Gas Phase Infrared Spectroscopy of Water Clusters and Cluster Ions Using Quantum Cascade Lasers  

E-print Network

Cascade Lasers Prospectus for Preliminary Examination Department of Chemistry, School of Chemical Sciences University of Illinois Jacob T. Stewart 29 April 2011 B124 CLSL 11:00 AM #12;1 Introduction Quantum cascade spectrum by varying the underlying quantum well structure of the laser chip. The original lasers had

McCall, Benjamin J.

307

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

308

High power, widely tunable, mode-hop free, continuous wave external cavity quantum cascade laser for multi-species trace gas detection  

NASA Astrophysics Data System (ADS)

We present a high power, widely tunable, continuous wave external cavity quantum cascade laser designed for infrared vibrational spectroscopy of molecules exhibiting broadband and single line absorption features. The laser source exhibits single mode operation with a tunability up to 303 cm-1 (˜24% of the center wavelength) at 8 ?m, with a maximum optical output power of 200 mW. In combination with off-axis integrated output spectroscopy, trace-gas detection of broadband absorption gases such as acetone was performed and a noise equivalent absorption sensitivity of 3.7 × 10-8 cm-1 Hz-1/2 was obtained.

Centeno, R.; Marchenko, D.; Mandon, J.; Cristescu, S. M.; Wulterkens, G.; Harren, F. J. M.

2014-12-01

309

Gas-phase photoacoustic sensor at 8.41 ?m using quartz tuning forks and amplitude-modulated quantum cascade lasers  

Microsoft Academic Search

We demonstrate the performance of a novel infrared photoacoustic laser absorbance sensor for gas-phase species using an amplitude-modulated\\u000a quantum cascade (QC) laser and a quartz tuning fork microphone. The photoacoustic signal was generated by focusing 5.3 mW\\u000a of a Fabry–Pérot QC laser operating at 8.41 ?m between the tines of a quartz tuning fork which served as a transducer for\\u000a the transient

Michael D. Wojcik; Mark C. Phillips; Bret D. Cannon; Matthew S. Taubman

2006-01-01

310

Quantum Hairs and Entropy of Quantum Isolated Horizon from Chern-Simons Theory  

E-print Network

We articulate the fact that the loop quantum gravity 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 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 Chern- Simons 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 Chern-Simons 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 semi-classical input from general relativity vis-a-vis the functional dependence of the IH 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 (P.M.), ensues straightforwardly, with precisely the coefficient -3/2, making it a signature of the loop quantum gravity approach to black hole entropy.

Abhishek Majhi; Parthasarathi Majumdar

2014-08-15

311

Ideal exhaustiveness, weak convergence and weak compactness in Banach spaces  

E-print Network

@yahoo.it Department of Mathematics, Jadavpur University, Kolkata-700032, West Bengal, India, email: pratu- lananda. Supported by Universities of Athens, Jadavpur and Perugia. Key words: (admissible) ideal, P-ideal, ideal

Boccuto, Antonio

312

Stochastic Quantum Gas Dynamics  

NASA Astrophysics Data System (ADS)

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

Proukakis, Nick P.; Cockburn, Stuart P.

2010-03-01

313

A principle for ideal torus knots  

NASA Astrophysics Data System (ADS)

Using bent-helix embeddings, we investigate simple and knotted torus windings that are made of tubes of finite thickness. Knots which have the shortest rope length are often denoted as ideal structures. Conventionally, the ideal structures are found by rope shortening routines. It is shown that alternatively they can be directly determined as maximally twisted structures. In many cases these structures are also structures with zero strain-twist coupling, i.e. structures that neither rotate one or the other way under strain. We use this principle to implement rapid numerical calculations of the ideal structures and subsequently quantify them by their aspect ratio. The results are compared with the aspect ratios of biological torus molecules.

Olsen, Kasper W.; Bohr, Jakob

2013-08-01

314

Lecture by John F. Nash Jr. Ideal Money and Asymptotically Ideal Money  

E-print Network

Lecture by John F. Nash Jr. Ideal Money and Asymptotically Ideal Money The special commodity or medium that we call money has a long and interesting history. And since we are so dependent on our use teaches, in effect, that "less is more" or that (in other words) "bad money is better than good money

Babu, G. Jogesh

315

Genetic Algorithms and Quantum Computation  

Microsoft Academic Search

Recently, researchers have applied genetic algorithms (GAs) to address some problems in quantum computation. Also, there has been some works in the designing of genetic algorithms based on quantum theoretical concepts and techniques. The so called Quantum Evolutionary Programming has two major sub-areas: Quantum Inspired Genetic Algorithms (QIGAs) and Quantum Genetic Algorithms (QGAs). The former adopts qubit chromosomes as representations

Gilson A. Giraldi; Renato Portugal; Ricardo N. Thess

2004-01-01

316

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.

317

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

318

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

319

Modeling gas dissolution in deepwater oil/gas spills  

NASA Astrophysics Data System (ADS)

Gases in deepwater oil/gas spills can lose considerable amounts of the gas phase due to dissolution in water. Gas dissolution has a significant impact on the behavior of the oil/gas jet/plume because of its impact on the buoyancy. A method is presented in this paper for computing gas dissolution that covers a broad range of water depth, from shallow water where gases behave as ideal ones under low pressure to deepwater where gases behave as non-ideal ones under high pressures. The method presented also accounts for the spherical and non-spherical shapes of gas bubbles. The gas dissolution computations are validated by comparing the computed results with observed data from previously conducted laboratory experiments. The gas dissolution computation module is then integrated with a model for underwater oil/gas jets/plumes by Yapa and Zheng [J. Hydraul. Res. 35 (5) (1997) 673]. Scenario simulations are presented to show the impacts of gas dissolution on the behavior of jets/plumes. These scenarios show the impact of dissolution on the behavior of the jet/plume. The comparison of results using ideal gas conditions and non-ideal gas conditions is also shown.

Zheng, Li; Yapa, Poojitha D.

2002-01-01

320

Molecular structures of 2-methoxyphenol and 1,2-dimethoxybenzene as studied by gas-phase electron diffraction and quantum chemical calculations  

NASA Astrophysics Data System (ADS)

The molecular structure and conformational properties of 2-methoxyphenol (2-MP) and 1,2-dimethoxybenzene (1,2-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). Of the three stable conformers predicted for 2-MP by quantum chemical calculations, the lowest energy form possesses a planar structure with an intramolecular hydrogen bond between phenolic hydrogen and methoxy oxygen ( anti-syn conformer of Cs symmetry). The calculated concentration of this conformer is about 99% and this is confirmed by the GED data. Quantum chemical calculations predict three stable conformers for 1,2-DMB: anti-anti ( C2v symmetry), anti-gauche ( C1 symmetry), and gauche-gauche ( C2 symmetry). The GED data were well reproduced for the mixture of these conformers with the relative abundance of 50 ± 12%, 36 ± 16%, and 14%, respectively. A similarly good agreement is also obtained for the single anti-gauche conformer. The experimental structural parameters agree well with results of B3LYP/cc-pVTZ calculations.

Dorofeeva, Olga V.; Shishkov, Igor F.; Karasev, Nikolai M.; Vilkov, Lev V.; Oberhammer, Heinz

2009-09-01

321

The World Grant Ideal and Engagement Scholarship  

ERIC Educational Resources Information Center

Michigan State University President Lou Anna Simon's concept of the world grant ideal is grounded in three core values: quality, inclusiveness, and connectivity. These core values fuel the 21st-century imperative to build sustainable global prosperity. They represent an affirmation of the Morrill Act of 1862 in the context of a global society and…

Fitzgerald, Hiram E.; Simon, Lou Anna K.

2012-01-01

322

Developing Ideal Student and Residency Programs.  

ERIC Educational Resources Information Center

The Veterans Administration (VA) is a primary educator of optometry students, with each college of optometry being affiliated with at least one VA hospital. Ideally, fourth-year optometry students rotate through a specific VA facility for about 12 weeks. Guidelines are designed to provide optimum care in a rich learning environment. (MSE)

Selvin, Gerald J.

1993-01-01

323

Ideal light concentrators with reflector gaps  

DOEpatents

A cylindrical or trough-like radiant energy concentration and collection device is provided. The device includes an energy absorber, a glazing enveloping the absorber and a reflective wall. The ideal contour of the reflective wall is determined with reference to a virtual absorber and not the actual absorber cross section.

Winston, Roland (Chicago, IL)

1980-01-01

324

Ideal orifice pulse tube refrigerator performance  

NASA Technical Reports Server (NTRS)

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

Kittel, P.

1992-01-01

325

Ideal orifice pulse tube refrigerator performance  

Microsoft Academic Search

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

P. Kittel

1992-01-01

326

Black teachers' perceptions of the ideal pupil.  

PubMed

Torrance's Ideal Child Checklist was administered to 76 black teachers. A comparison of their 10 most and least valued traits with those of the expert panel on the creative personality showed that the two groups agreed only once on the 10 most valued traits and three times on the 10 least valued traits. PMID:604881

Kaltsounis, B; Higdon, G

1977-12-01

327

Ideal spatial adaptation by wavelet shrinkage  

Microsoft Academic Search

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

DAVID L. DON; IAIN M. JOHNSTONE

1993-01-01

328

Ideal Spatial Adaptation by Wavelet Shrinkage  

Microsoft Academic Search

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

1994-01-01

329

Project IDEALS. Educational Applications of Computer Systems.  

ERIC Educational Resources Information Center

This is a booklet in the Project IDEALS series which deals with the use of Educational Data Processing (EDP) systems. A section is devoted to the use of the computer in such varied school operations as the processing of student records, schedules, computer simulation, grade reports, business, student applications, cafeterias, and transportation.…

Hansen, Duncan; And Others

330

Axisymmetric ideal MHD stellar wind flow  

NASA Technical Reports Server (NTRS)

The ideal MHD equations are reduced to a single equation under the assumption of axisymmetric flow. A variational principle from which the equation is derivable is given. The characteristics of the equation are briefly discussed. The equation is used to rederive the theorem of Gussenhoven and Carovillano.

Heinemann, M.; Olbert, S.

1978-01-01

331

Effect of quantum tunneling on single strand breaks in a modeled gas phase cytidine nucleotide induced by low energy electron: A theoretical approach  

NASA Astrophysics Data System (ADS)

Effect of quantum mechanical tunneling on single strand breaks induced by low energy electron (LEE) has been investigated in a modeled gas phase system, 2'-deoxycytidine-3'-monophosphate (3'-dCMPH). The potential energy curves for the sugar-phosphate C-O (3' C-O) bond cleavage have been generated using second order Møller-Plesset perturbation theory at the 6-31+G(d) accuracy level. Results from the electronic structure theory calculations in conjunction with our time dependent calculations for the 3' C-O bond rupture in 3'-dCMPH using local complex potential based time dependent wave packet approach show significant quantum tunneling of the 3' C-O bond from the bound vibrational states above 1 eV of the anionic potential energy curve. A comparison of the fragmentation profile with that of our earlier gas phase investigations based on Hartree-Fock and density functional theory - Becke, 3-parameter, Lee-Yang-Parr methods with 6-31+G(d) basis set is also provided. Further, inspection of the singly occupied molecular orbitals generated at different 3' C-O bond lengths clearly indicates the electron transfer from the low lying base-?* shape resonance state to the phosphate P = O ?* orbital of the DNA backbone during the strand breaks. The decisive step during LEE induced strand breaks follows via "charge induced dissociation" (CID) for the metastable anion formed below 1 eV, whereas quantum mechanical tunnel-ing is out-weighted the CID mechanism for the LEE above 1 eV.

Bhaskaran, Renjith; Sarma, Manabendra

2013-07-01

332

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

333

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

334

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

2014-05-07

335

Non-ideal Solution Thermodynamics of Cytoplasm  

PubMed Central

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

Ross-Rodriguez, Lisa U.; McGann, Locksley E.

2012-01-01

336

Ideal photon number amplifier and duplicator  

NASA Technical Reports Server (NTRS)

The photon number-amplification and number-duplication mechanism are analyzed in the ideal case. The search for unitary evolutions leads to consider also a number-deamplification mechanism, the symmetry between amplification and deamplification being broken by the integer-value nature of the number operator. Both transformations, amplification and duplication, need an auxiliary field which, in the case of amplification, turns out to be amplified in the inverse way. Input-output energy conservation is accounted for using a classical pump or through frequency-conversion of the fields. Ignoring one of the fields is equivalent to considering the amplifier as an open system involving entropy production. The Hamiltonians of the ideal devices are given and compared with those of realistic systems.

Dariano, G. M.

1992-01-01

337

Far-infrared collision-induced absorption in rare gas mixtures: Quantum and semi-classical calculations  

SciTech Connect

We compare calculations of the translational collision-induced spectra and their integrated intensities of both He–Ar and Ne–Ar collisional complexes, using the quantum mechanical and a semiclassical formalism. Advanced potential energy and induced dipole functions are used for the calculations. The quantum method used is as described previously [L. Frommhold, Collision-induced Absorption in Gases (Cambridge University Press, 1993 and 2006)]. The semiclassical method is based on repeated classical atom-atom scattering calculations to simulate an ensemble average; subsequent Fourier transform then renders the binary absorption coefficient as a function of frequency. The problem of classical calculations is the violation of the principle of detailed balance, which may be introduced only artificially in classical calculations. Nevertheless, it is shown that the use of classical trajectories permits a fairly accurate reproduction of the experimental spectra, comparable to the quantum mechanical results at not too low temperatures and for collisional pairs of not too small reduced mass. Inexpensive classical calculations may thus be promising to compute spectra also of molecular pairs, or even of polyatomic collisional pairs with anisotropic intermolecular interactions, for which the quantum approach is still inefficient or impractical.

Buryak, Ilya [Chemistry Department, Lomonosov Moscow State University, GSP-1, Vorobievy Gory, Moscow 119991 (Russian Federation) [Chemistry Department, Lomonosov Moscow State University, GSP-1, Vorobievy Gory, Moscow 119991 (Russian Federation); Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, 3 Pyzhevsky per., 119017 Moscow (Russian Federation); Frommhold, Lothar [Physics Department, University of Texas at Austin, Austin, Texas 78712-1081 (United States)] [Physics Department, University of Texas at Austin, Austin, Texas 78712-1081 (United States); Vigasin, Andrey A., E-mail: vigasin@ifaran.ru [Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, 3 Pyzhevsky per., 119017 Moscow (Russian Federation)

2014-04-21

338

Quad quantum cascade laser spectrometer with dual gas cells for the simultaneous analysis of mainstream and sidestream cigarette smoke  

Microsoft Academic Search

A compact, fast response, infrared spectrometer using four pulsed quantum cascade (QC) lasers has been applied to the analysis of gases in mainstream (MS) and sidestream (SS) cigarette smoke. QC lasers have many advantages over the traditional lead-salt tunable diode lasers, including near room temperature operation with thermoelectric cooling and single mode operation with improved long-term stability. The new instrument

Randall E. Baren; Milton E. Parrish; Kenneth H. Shafer; Charles N. Harward; Quan Shi; David D. Nelson; J. Barry McManus; Mark S. Zahniser

2004-01-01

339

The Ideally Active: Frances Willard's Pedagogical Ministry  

E-print Network

prayers took us to the very gates of heaven. Louise Hart, Student. Woman?s College, Northwestern University, September 22, 1923. Such broad views of life and destiny as she opened to our sight; such high ideals of character as she set before us... and temperance leader, Willard enacted what Kenneth Burke describes as a ?general body of identifications that owe their convincingness much more to trivial repetition and dull daily reinforcement than to exceptional rhetorical skill? (26). Although Willard...

Graham, Jane Robson

2008-01-01

340

CMHOG: Code for Ideal Compressible Hydrodynamics  

NASA Astrophysics Data System (ADS)

CMHOG (Connection Machine Higher Order Godunov) is a code for ideal compressible hydrodynamics based on the Lagrange-plus-remap version of the piecewise parabolic method (PPM) of Colella & Woodward (1984, J. Comp. Phys., 74, 1). It works in one-, two- or three-dimensional Cartesian coordinates with either an adiabatic or isothermal equation of state. A limited amount of extra physics has been added using operator splitting, including optically-thin radiative cooling, and chemistry for combustion simulations.

Piner, B. Glenn; Stone, James M.; Teuben, Peter J.

2011-01-01

341

Theoretical considerations for the ideal aromatase inhibitor  

Microsoft Academic Search

A definition of the theoretical components of an ideal aromatase inhibitor is developed, one aspect of which is completeness\\u000a of enzyme inhibition. The three triazole inhibitors, letrozole, vorozole and anastrozole all inhibit whole body aromatisation\\u000a by > 96% at their clinically used doses and vorozole and letrozole were more effective in Phase III clinical trials than aminoglutethimide\\u000a (250 mg bd)

M. Dowsett

1998-01-01

342

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...?maintenance?costs ? Environmental?credentials ?Comfortable?customers?and?staff ?Improved?morale 18 The ?Super? Market ? Supermarket?industry ?Already?proven?results ?More?opportunities?available ?Challenges?can?be?overcome ? Financial,?environmental?and? community...

Dazeley, J.

2012-01-01

343

Joule-Thomson coefficient of ideal anyons within fractional exclusion statistics  

SciTech Connect

The analytical expressions of the Joule-Thomson coefficient for homogeneous and harmonically trapped three-dimensional ideal anyons which obey Haldane fractional exclusion statistics are derived. For an ideal Fermi gas, the Joule-Thomson coefficient is negative, which means that there is no maximum Joule-Thomson inversion temperature. With careful study, it is found that there exists a Joule-Thomson inversion temperature in the fractional exclusion statistics model. Furthermore, the relations between the Joule-Thomson inversion temperature and the statistical parameter g are investigated.

Qin Fang; Chen Jisheng [Physics Department and Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China)

2011-02-15

344

Medical ethics and more: ideal theories, non-ideal theories and conscientious objection.  

PubMed

Doing 'good medical ethics' requires acknowledgment that it is often practised in non-ideal circumstances! In this article I present the distinction between ideal theory (IT) and non-ideal theory (NIT). I show how IT may not be the best solution to tackle problems in non-ideal contexts. I sketch a NIT framework as a useful tool for bioethics and medical ethics and explain how NITs can contribute to policy design in non-ideal circumstances. Different NITs can coexist and be evaluated vis-à-vis the IT. Additionally, I address what an individual doctor ought to do in this non-ideal context with the view that knowledge of NITs can facilitate the decision-making process. NITs help conceptualise problems faced in the context of non-compliance and scarcity in a better and more realistic way. Deciding which policy is optimal in such contexts may influence physicians' decisions regarding their patients. Thus, this analysis-usually identified only with policy making-may also be relevant to medical ethics. Finally, I recognise that this is merely a first step in an unexplored but fundamental theoretical area and that more work needs to be done. PMID:25516954

Luna, Florencia

2015-01-01

345

Dimensional Analysis Using Toric Ideals: Primitive Invariants  

PubMed Central

Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer matrix from the initial integer matrix holding the exponents for the derived quantities. The matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups) is obtained directly from the toric ideal defined by . One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of , is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found. PMID:25436774

Atherton, Mark A.; Bates, Ronald A.; Wynn, Henry P.

2014-01-01

346

Informational derivation of quantum theory  

SciTech Connect

We derive quantum theory from purely informational principles. Five elementary axioms - causality, perfect distinguishability, ideal compression, local distinguishability, and pure conditioning - define a broad class of theories of information processing that can be regarded as standard. One postulate - purification - singles out quantum theory within this class.

Chiribella, Giulio; D'Ariano, Giacomo Mauro; Perinotti, Paolo [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Ontario, N2L 2Y5 (Canada); QUIT Group, Dipartimento di Fisica ''A. Volta'' and INFN Sezione di Pavia, via Bassi 6, I-27100 Pavia (Italy)

2011-07-15

347

Ideal Fluids, the Quark Gluon Plasma, and Hadronic Gases  

NASA Astrophysics Data System (ADS)

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

Demir, Nasser

2015-01-01

348

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

349

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

NASA Astrophysics Data System (ADS)

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

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

2010-02-01

350

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

351

QUANTUM CRYPTOGRAPHY QUANTUM COMPUTING  

E-print Network

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

Bachoc, Christine

352

Hamiltonian description of the ideal fluid  

SciTech Connect

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

Morrison, P.J.

1994-01-01

353

Synthetic quantum matter under a Harvard University  

E-print Network

to experimentally quantum many body systems at extreme low temperatures. Using our bosonic quantum gas microscope/Coffee at Seminar Hall, TCIS Seminar Synthetic quantum matter under a microscope Rajibul Islam Harvard University at extreme low temperatures. Using our bosonic quantum gas icroscope set up we create arbitrary optical

Shyamasundar, R.K.

354

Field topologies in ideal and near ideal magnetohydrodynamics and vortex dynamics  

E-print Network

Magnetic field topology frozen in ideal magnetohydrodynamics (MHD) and its breakage in near ideal MHD are reviewed in two parts. The first part gives a physically complete description of the frozen in field topology, taking magnetic flux conservation as fundamental and treating four topics, Eulerian and Lagrangian descriptions of MHD, Chandrasekhar-Kendall and Euler-potential field representations, magnetic helicity, and inviscid vortex dynamics in comparison to ideal MHD. A corollary clarifies the challenge of achieving a high degree of the frozen in condition in numerical MHD. The second part treats field topology breakage centered on the Parker Magnetostatic Theorem on a general incompatibility of a continuous magnetic field with the dual demand of force free equilibrium and an arbitrarily prescribed, 3D field topology. Preserving field topology as a global constraint readily results in formation of tangential magnetic discontinuities, i.e., electric current sheets of zero thickness. A similar incompatibil...

Low, B C

2014-01-01

355

Quantum coin flipping with arbitrary small bias is impossible  

Microsoft Academic Search

Lo and Chau showed that an ideal quantum coin flipping protocol is impossible. The proof was simply derived from the impossibility proof of quantum bit commitment. However, the proof still leaves the possibility of a quantum coin flipping protocol with arbitrary small bias. In this paper, we show that a quantum coin flipping protocol with arbitrary small bias is impossible

Yuki Tokunaga

2001-01-01

356

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

357

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

SciTech Connect

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

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

2014-05-04

358

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

359

Ideal polymers near scale-free surfaces.  

PubMed

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. PMID:25353496

Hammer, Yosi; Kantor, Yacov

2014-02-01

360

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

361

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

362

Structural fat grafts: the ideal filler?  

PubMed

In the search for injectable subcutaneous fillers, fat harvested, transferred, and placed in the manner previously described has most of the characteristics of an ideal filler. It is biocompatible, versatile, stable, long-lasting, and natural-appearing. The key to successful fat grafting lies in the technique. Harvesting, refinement, and transfer of subcutaneous tissue to provide pure, intact parcels of fat are essential for successful fat grafting. The surgeon also must infiltrate the refined fat parcels into the recipient site so that they survive predictably and uniformly, become integrated into the host tissues, and accomplish the desired structural alteration. The key to attaining these goals is the placement of minuscule amounts of fatty tissue with each withdrawal of the infiltrating cannula. This maneuver maximizes the surface area of contact between the newly transplanted tissues and the recipient tissues. Applying this technique to enact structural volume alteration of the face can result in subtle or striking improvements in the appearance of patients. The ideal substance for soft-tissue augmentation still eludes physicians, but fat grafting through a blunt cannula seems to be the safest of all of the fillers used; in the hands of an experienced surgeon, it can provide long-lasting, natural-appearing structural changes. PMID:11248861

Coleman, S R

2001-01-01

363

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

364

Simple Waves in Ideal Radiation Hydrodynamics  

E-print Network

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.

Bryan M. Johnson

2008-11-24

365

Thermodynamics of an idealized hydrologic cycle  

NASA Astrophysics Data System (ADS)

The diurnal hydrologic cycle, a sequence of evapotranspiration, boundary layer growth, moist convection, and precipitation, is described in a thermodynamic framework, assuming an atmosphere composed solely of water. This idealized cycle is shown to be equivalent to an abbreviated version of the classical Rankine cycle where not all the water vapor is condensed. Energy and entropy fluxes of the processes involved in the cycle are quantified using the reversible approximation as a function of the quality of the liquid-vapor mixture (the ratio of the residual background vapor and the total mass of water) and the different temperatures at which evaporation and condensation take place. The proposed framework allows quantitative estimates of the net work (which is used by the cycle to drive the atmospheric circulation and dissipated by various frictional forces and nonidealities) as well as of the thermodynamic efficiency of the cycle. Possible extensions of the idealized framework relating to the role of dry air and the inclusion of various irreversible processes are also discussed.

Konings, Alexandra G.; Feng, Xue; Molini, Annalisa; Manzoni, Stefano; Vico, Giulia; Porporato, Amilcare

2012-05-01

366

Operator Ideals in Lipschitz and Operator Spaces Categories  

E-print Network

nonlinear ideals of operators including the ideal of Lipschitz p-summing operators and the ideal of factorization through a subset of a Hilbert space. We prove metric characterizations of p-convex operators, and also of those with Rademacher type and cotype...

Chavez Dominguez, Javier

2012-10-19

367

Examples for Non-Ideal Solution Thermodynamics Study  

ERIC Educational Resources Information Center

A mathematical model of a non-ideal solution is presented, where it is shown how and where the non-ideality manifests itself in the standard thermodynamics tableau. Examples related to the non-ideal solution thermodynamics study are also included.

David, Carl W.

2004-01-01

368

ASYMPTOTIC MULTIPLICITIES OF GRADED FAMILIES OF IDEALS AND LINEAR SERIES  

E-print Network

. Introduction 1.1. Limits of graded families of ideals. In this paper we prove the following theorem about graded families of mR-primary ideals. Theorem 1.1. (Theorem 5.5) Suppose that R is a (Noetherian) local of mR-primary ideals in a regular local ring such that the above limit is irrational. The problem

Cutkosky, Dale

369

Rings over which all projective ideal is free  

E-print Network

In this paper we introduce and investigate a class of those rings in which every projective ideal is free. We establish the transfer of this notion to the trivial ring extension and pullbacks and then generate new and original families of rings satisfying this property. Key Words. Projective ideal, free ideal, Trivial ring extensions, Pullbacks.

Chahrazade Bakkari; Najib Mahdou

370

Rings over which every projective ideal is free  

E-print Network

In this paper we introduce and investigate a class of those rings in which every projective ideal is free. We establish the transfer of this notion to the trivial ring extension and pullbacks and then generate new and original families of rings satisfying this property. Key Words. Projective ideal, free ideal, Trivial ring extensions, Pullbacks.

Chahrazade Bakkari; Najib Mahdou

371

On almost precipitous ideals. Asaf Ferber and Moti Gitik  

E-print Network

On almost precipitous ideals. Asaf Ferber and Moti Gitik July 21, 2008 Abstract We answer questions concerning an existence of almost precipitous ideals raised in [5]. It is shown that every successor of a regular cardinal can carry an almost precipitous ideal in a generic extension of L. In L

Gitik, Moti

372

ON NORMAL PRECIPITOUS IDEALS SCHOOL OF MATHEMATICAL SCIENCES  

E-print Network

ON NORMAL PRECIPITOUS IDEALS MOTI GITIK SCHOOL OF MATHEMATICAL SCIENCES RAYMOND AND BEVERLY SACKLER and K. Prikry asks if an existence of a precipitous ideal implies necessary existence of a normal precipitous ideal. The aim of the paper is to prove some results in the positive direction. Thus, it is shown

Gitik, Moti

373

Level Reduction and the Quantum Threshold Theorem  

E-print Network

The quantum threshold theorem shows that a noisy quantum computer can accurately and efficiently simulate any ideal quantum computation provided that noise is weakly correlated and its strength is below a critical value known as the quantum accuracy threshold. This thesis provides a simpler and more transparent non-inductive proof of this theorem based on the concept of level reduction. This concept is also used in proving the quantum threshold theorem for coherent and leakage noise and for quantum computation by measurements. In addition, the proof provides a methodology which allows us to establish improved rigorous lower bounds on the value of the quantum accuracy threshold.

Panos Aliferis

2007-03-25

374

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

375

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

376

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

E-print Network

Christiana Honsberg Derivation of the ideal diode equation for solar cells Derivation of the Ideal of the ideal diode equation for solar cells General Procedure using the depletion approximation: Divide is confined to a particular region. (2) No free carriers (n(x), p(x) = 0 ) in depletion region. We can assume

Honsberg, Christiana

377

Stability of ideal fcc twin boundaries  

NASA Astrophysics Data System (ADS)

Ideas from continuum mechanics are used to derive an elastic stability inequality for a boundary between two different materials under quasi-static, homogeneous conditions. The terms in this inequality are interpreted for the case of an ideal twinning plane between two variants of a face-centered cubic material. High quality potentials for Ni and Cu are used in molecular dynamics calculations to calibrate relevant energies and displacements near the twinning plane. It is found that in comparison with direct molecular dynamics calculations the inequality predicts the critical stress that initiates movement of the twinning plane in Ni within 1.9% and within 1.3% for Cu. Although the predicted and calculated critical stresses are only upper bounds for the more realistic case of an imperfect boundary, the calculations give considerable insight into the interplay of energies that lead to boundary motion.

Wright, T. W.; Daphalapurkar, N. P.; Ramesh, K. T.

2014-12-01

378

Ideal graphene/silicon Schottky junction diodes.  

PubMed

The proper understanding of semiconductor devices begins at the metal-semiconductor interface. The metal/semiconductor interface itself can also be an important device, as Schottky junctions often forms when the doping in the semiconductors is low. Here, we extend the analysis of metal-silicon Schottky junctions by using graphene, an atomically thin semimetal. We show that a fundamentally new transport model is needed to describe the graphene-silicon Schottky junction. While the current-voltage behavior follows the celebrated ideal diode behavior, the details of the diode characteristics is best characterized by the Landauer transport formalism, suggesting that the injection rate from graphene ultimately determines the transport properties of this new Schottky junction. PMID:25000510

Sinha, Dhiraj; Lee, Ji Ung

2014-08-13

379

Ideal ballooning modes in axisymmetric mirror machines  

SciTech Connect

A simple code is described that finds marginally stable (..omega../sup 2/ = 0) ballooning-type MHD modes, localized about a field line in an axisymmetric, open-ended, plasma confinement device. The equations are based on a lower bound for the perturbed energy delta W, derived by W. Newcomb from the ideal MHD energy principle, and are cast in the form of a Ricatti equation for the first derivative of the eigenfunction, with the open boundary conditions that this derivative vanish at the plasma boundary down each field line. The input to the code is the two-dimensional shape of a field line, the field strength B(s), and parameters to define pressure profiles throughout the system. The objective is to find the highest plasma pressures for which the given line is MHD-stable.

Baldwin, D.E.; McNamara, B.; Willmann, P.

1980-12-15

380

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

381

IDEAL: A methology for developing information systems  

NASA Technical Reports Server (NTRS)

As a result of improved capabilities obtained through current computer technologies, application programs and expert systems, Enterprises are being designed or upgraded to be highly integrated and automated information systems. To design or modify Enterprises, it is necessary to first define what functions are to be performed within the Enterprise, identify which functions are potential candidates for automation, and what automated or expert systems are available, or must be developed, to accomplish the selected function. Second, it is necessary to define and analyze the informational requirements for each function along with the informational relationships among the functions so that a database structure can be established to support the Enterprise. To perform this type of system design, an integrated set of analysis tools is required to support the information analysis process. The IDEAL (Integrated Design and Engineering Analysis Languages) methodology provides this integrated set of tools and is discussed.

Evers, Ken H.; Bachert, Robert F.

1988-01-01

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

Real-time trace gas sensing of fluorocarbons using a swept-wavelength external cavity quantum cascade laser.  

PubMed

We present results demonstrating real-time sensing of four different fluorocarbons at low part-per billion (ppb) concentrations using an external cavity quantum cascade laser (ECQCL) designed for infrared vibrational spectroscopy of molecules with broad absorption features. The ECQCL was repeatedly swept at 20 Hz over its full tuning range of 1145-1265 cm(-1) providing a scan rate of 3535 cm(-1) s(-1), and a detailed characterization of the ECQCL scan stability and repeatability is presented. The ECQCL was combined with a 100 meter path length multi-pass cell for direct absorption spectroscopy. A portable sensor system is described, which was deployed on a mobile automotive platform to provide spatially-resolved detection of fluorocarbons in outdoor experiments. Noise-equivalent detection limits of 800-1000 parts-per-trillion (ppt) are demonstrated for 1 s integration times. PMID:24384671

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

2014-05-01

384

Extracting the Chern number from the dynamics of a Fermi gas: implementing a quantum Hall bar for cold atoms.  

PubMed

We propose a scheme to measure the quantized Hall conductivity of an ultracold Fermi gas initially prepared in a topological Chern insulating phase and driven by a constant force. We show that the time evolution of the center of mass, after releasing the cloud, provides a direct and clear signature of the topologically invariant Chern number. We discuss the validity of this scheme, highlighting the importance of driving the system with a sufficiently strong force to displace the cloud over measurable distances while avoiding band-mixing effects. The unusual shapes of the driven atomic cloud are qualitatively discussed in terms of a semiclassical approach. PMID:24116789

Dauphin, Alexandre; Goldman, Nathan

2013-09-27

385

The influence of the temperature and density of an electron gas on beta processes in a quantum magnetic field  

NASA Astrophysics Data System (ADS)

Beta processes occurring upon variation of the temperature and density of an electron gas in a wide range are investigated by accounting for the effect of a strong magnetic field on the motion of charged particles. The study is performed in the Furry framework. Inherent to the case considered is that, for certain relationships between the main parameters of the problem, the probabilities of beta processes and the neutrino luminosities caused by them exhibit an oscillatory behavior. In the degeneracy case, the interference effects reflecting the nonanalyticity of the expressions upon field vanishing exceed the contributions from perturbation theory. The results are of interest in connection with the collapse of massive stellar nuclei.

Rodionov, V. N.; Starcheus, S. G.; Tasev, M. A.; Ternov, I. M.

1988-01-01

386

Faked states attack and quantum cryptography protocols  

E-print Network

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

Denny, Travis

2011-01-01

387

Quantum computation: algorithms and implementation in quantum dot devices  

NASA Astrophysics Data System (ADS)

In this thesis, we explore several aspects of both the software and hardware of quantum computation. First, we examine the computational power of multi-particle quantum random walks in terms of distinguishing mathematical graphs. We study both interacting and non-interacting multi-particle walks on strongly regular graphs, proving some limitations on distinguishing powers and presenting extensive numerical evidence indicative of interactions providing more distinguishing power. We then study the recently proposed adiabatic quantum algorithm for Google PageRank, and show that it exhibits power-law scaling for realistic WWW-like graphs. Turning to hardware, we next analyze the thermal physics of two nearby 2D electron gas (2DEG), and show that an analogue of the Coulomb drag effect exists for heat transfer. In some distance and temperature, this heat transfer is more significant than phonon dissipation channels. After that, we study the dephasing of two-electron states in a single silicon quantum dot. Specifically, we consider dephasing due to the electron-phonon coupling and charge noise, separately treating orbital and valley excitations. In an ideal system, dephasing due to charge noise is strongly suppressed due to a vanishing dipole moment. However, introduction of disorder or anharmonicity leads to large effective dipole moments, and hence possibly strong dephasing. Building on this work, we next consider more realistic systems, including structural disorder systems. We present experiment and theory, which demonstrate energy levels that vary with quantum dot translation, implying a structurally disordered system. Finally, we turn to the issues of valley mixing and valley-orbit hybridization, which occurs due to atomic-scale disorder at quantum well interfaces. We develop a new theoretical approach to study these effects, which we name the disorder-expansion technique. We demonstrate that this method successfully reproduces atomistic tight-binding techniques, while using a fraction of the computational resources and providing considerably more physical insight. Using this technique, we demonstrate that large dipole moments can exist between valley states in disordered systems, and calculate corrections to intervalley tunnel rates..

Gamble, John King

388

Quantum quench and prethermalization dynamics in a two-dimensional fermi gas with long-range interactions.  

PubMed

We study the effect of suddenly turning on a long-range interaction in a spinless Fermi gas in two dimensions. The short- to intermediate-time dynamics is described using the method of bosonization of the Fermi surface. The space-time dependence of the nonequilibrium fermion density matrix as well as the evolution after the quench of the discontinuity at the Fermi momentum of the momentum distribution are computed. We find that the asymptotic state predicted by bosonization is consistent with the existence of a prethermalization plateau, which is also predicted by a perturbative approach in terms of the fermionic degrees of freedom. The bosonized representation, however, explicitly allows for the construction of the generalized Gibbs ensemble describing the prethermalized state. PMID:25479478

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

2014-11-21

389

Molecular structure and benzene ring deformation of three cyanobenzenes from gas-phase electron diffraction and quantum chemical calculations.  

PubMed

The molecular structures of cyanobenzene, p-dicyanobenzene, and 1,2,4,5-tetracyanobenzene have been accurately determined by gas-phase electron diffraction and ab initio/DFT MO calculations. The equilibrium structures of these molecules are planar, but their average geometries in the gaseous phase are nonplanar because of large-amplitude vibrational motions of the substituents out of the plane of the benzene ring. The use of nonplanar models in electron diffraction analysis is necessary to yield ring angles consistent with the results of MO calculations. The angular deformation of the benzene ring in the three molecules is found to be much smaller than obtained from previous electron diffraction studies, as well as from microwave spectroscopy studies of cyanobenzene. While the deformation of the ring CC bonds and CCC angles in p-dicyanobenzene is well interpreted as arising from the superposition of independent effects from each substituent, considerable deviation from additivity occurs in 1,2,4,5-tetracyanobenzene. The changes in the ring geometry and C ipso-C cyano bond lengths in this molecule indicate an enhanced ability of the cyano group to withdraw pi-electrons from the benzene ring, compared with cyanobenzene and p-dicyanobenzene. In particular, gas-phase electron diffraction and MP2 or B3LYP calculations show a small but consistent increase in the mean length of the ring CC bonds for each cyano group and a further increase in 1,2,4,5-tetracyanobenzene. Comparison with accurate results from X-ray and neutron crystallography indicates that in p-dicyanobenzene the internal ring angle at the place of substitution opens slightly as the molecule is frozen in the crystal. The small geometrical change, about 0.6 degrees , is shown to be real and to originate from intermolecular C identical withN...HC interactions in the solid state. PMID:18834088

Campanelli, Anna Rita; Domenicano, Aldo; Ramondo, Fabio; Hargittai, István

2008-10-30

390

Family Life and Developmental Idealism in Yazd, Iran  

PubMed Central

BACKGROUND This paper is motivated by the theory that developmental idealism has been disseminated globally and has become an international force for family and demographic change. Developmental idealism is a set of cultural beliefs and values about development and how development relates to family and demographic behavior. It holds that modern societies are causal forces producing modern families, that modern families help to produce modern societies, and that modern family change is to be expected. OBJECTIVE We examine the extent to which developmental idealism has been disseminated in Iran. We also investigate predictors of the dissemination of developmental idealism. METHODS We use survey data collected in 2007 from a sample of women in Yazd, a city in Iran. We examine the distribution of developmental idealism in the sample and the multivariate predictors of developmental idealism. RESULTS We find considerable support for the expectation that many elements of developmental idealism have been widely disseminated. Statistically significant majorities associate development with particular family attributes, believe that development causes change in families, believe that fertility reductions and age-at-marriage increases help foster development, and perceive family trends in Iran headed toward modernity. As predicted, parental education, respondent education, and income affect adherence to developmental idealism. CONCLUSIONS Developmental idealism has been widely disseminated in Yazd, Iran and is related to social and demographic factors in predicted ways. COMMENTS Although our data come from only one city, we expect that developmental idealism has been widely distributed in Iran, with important implications for family and demographic behavior. PMID:22942772

Abbasi-Shavazi, Mohammad Jalal; Askari-Nodoushan, Abbas

2012-01-01

391

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

SciTech Connect

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

Diehl, S.; Daley, A. J.; Zoller, P. [Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Baranov, M. [Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); RRC 'Kurchatov Institute', Kurchatov Square 1, 123182 Moscow (Russian Federation)

2010-08-01

392

Genetic Algorithms and Quantum Computation  

Microsoft Academic Search

Recently, researchers have applied genetic algorithms (GAs) to address some\\u000aproblems in quantum computation. Also, there has been some works in the\\u000adesigning of genetic algorithms based on quantum theoretical concepts and\\u000atechniques. The so called Quantum Evolutionary Programming has two major\\u000asub-areas: Quantum Inspired Genetic Algorithms (QIGAs) and Quantum Genetic\\u000aAlgorithms (QGAs). The former adopts qubit chromosomes as representations

Gilson A. Giraldi; Renato Portugal; Ricardo N. Thess

2004-01-01

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

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

PubMed Central

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

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

2014-01-01

395

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

NASA Astrophysics Data System (ADS)

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

Low, B. C.

2014-12-01

396

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

NASA Astrophysics Data System (ADS)

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

Low, B. C.

2015-01-01

397

Nonlinear filtering and limiting in high order methods for ideal and non-ideal MHD  

NASA Technical Reports Server (NTRS)

The various filtering mechanisms and base scheme options of the newly developed adaptive numerical dissipation control in spatially high order filter schemes for the ideal and non-ideal magnetohydrodynamics (MHD) equations are investigated. 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 type of spatial base scheme to be used in conjunction with our filter idea is very general. For example, spectral, compact and non-compact spatially central finite difference schemes are possible candidates. 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 to 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 also very general. The objective of this paper is to investigate the performance of using compact and non-compact central base schemes in conjunction with three commonly used types of nonlinear numerical dissipation for both the ideal and non-ideal MHD. This extended abstract shows the performance of three nonlinear filters in conjunction with a sixth-order non-compact spatial central base scheme. In the final paper, the high order compact spatial central base scheme will be illustrated and compared with the non-compact base scheme. The reason for the investigation of the high order compact spatial central base scheme over the non-compact base scheme is to evaluate if additional accuracy can be gained in regions of fine scale turbulence that are away from shocks/shears.

Yee,H. C.; Sjogreen, B.

2004-01-01

398

Low-energy positron scattering from gas-phase pyrimidine: A quantum treatment of the dynamics and a comparison with experiments  

NASA Astrophysics Data System (ADS)

In the present work we are reporting detailed quantum scattering calculations that describe the diffusion of a beam of low-energy positrons interacting with the pyrimidine target as a gas-phase partner. The calculations have employed an essentially ab initio model for the short-range correlation interaction and for the electrostatic interaction of an impinging positron and the electron+nuclear structure of the target molecule at its equilibrium geometry. The available experiments were also performed in the low-energy region below about 30 eV and have been reported by two different experimental groups cited in the main text. Those data include integral elastic plus rotationally and vibrationally summed cross sections, together with angular distributions over the same range of energies. The effects on the scattering observables which stem from the permanent dipole moment of the title molecule are carefully analyzed and computational corrections which ensure numerical convergence are introduced and discussed. The additional uncertainties introduced by the angular discrimination error present in the experiments are also discussed and analyzed, thereby providing a numerical procedure for correcting all available data. The final comparison between experimental angular distributions and the computed counterparts produced in the present work turns out to be very good. The same applies to the comparison in size and energy dependence of the integral cross sections, where we show that our calculated quantities and the corrected experiments are in very good agreement over the whole range of available energies.

Franz, J.; Gianturco, F. A.

2013-10-01

399

Photoluminescence of charged CdSe/ZnS quantum dots in the gas phase: effects of charge and heating on absorption and emission probabilities.  

PubMed

Gas phase spectral measurements for CdSe/ZnS core/shell nanocrystal quantum dots (QDs) before and after heating with both infrared (CO2) and visible lasers are reported. As-trapped QDs are spectrally similar to the same QDs in solution; however their photoluminescence (PL) intensities are very low, at least partly due to low absorption cross sections. After heating, the PL intensities brighten by factors ranging from ?4 to 1800 depending on the QD size and pump laser wavelength. The emission spectra no longer resemble solution spectra and are similar, regardless of the QD diameter. Emission extends from the pump laser wavelength into the near-IR, with strong emission features above the band gap energy, between 645 and 775 nm, and in the near-infrared. Emission spectra from brightened QD ensembles, single QD aggregates, and single QD monomers are similar, showing that even single QDs support PL from a wide variety of states. The heating and cooling processes for QDs in this environment are analyzed, providing limits on the magnitudes of the absorption cross sections before and after thermal brightening. A model, based on absorption bleaching by extra electrons in the conduction band, appears to account for the changes in absorption and emission behavior induced by charging and heating. PMID:25427008

Howder, Collin R; Long, Bryan A; Bell, David M; Furakawa, Kevin H; Johnson, Ryan C; Fang, Zhiyuan; Anderson, Scott L

2014-12-23

400

Landau levels and spin splitting in the two-dimensional electron gas of a HgTe quantum well near the critical width for the topological phase transition  

NASA Astrophysics Data System (ADS)

We report a detailed low-temperature study of the two-dimensional (2D) electron gas in a 6.1-nm-wide HgTe quantum well with H g0.3C d0.7Te barriers by terahertz magnetophotoconductivity and magnetotransmission combined with magnetotransport measurements (Rx x and Rx y) in magnetic fields up to 10 T. This well width, close to that at the topological phase transition, corresponds to conventional band ordering, and we probe the "bulk" quasi-2D Landau-level (LL) spectrum of the conduction band at high energies (?135 -160 meV ) above the Dirac point. The calculated separations between adjacent LLs of the same spin based on published parameters for this structure are in fair agreement with the measured cyclotron resonance energies. However, the very large spin splittings observed (Espin>Ecyclotron) require a significantly larger g -parameter ge for electrons. Tilted field coincidence experiments are consistent with the large spin splitting showing coincidences at 3/2 and twice the cyclotron energy. This large value of ge also leads to interesting crossings of the calculated LLs, and we find direct evidence of these crossings in the Rx x measurements at lower electron densities (Fermi energies) produced by negative gate bias.

Pakmehr, M.; Bruene, C.; Buhmann, H.; Molenkamp, L. W.; Stier, A. V.; McCombe, B. D.

2014-12-01

401

Finite lifetimes of ideal poloidal Alfvén waves  

NASA Astrophysics Data System (ADS)

Standing second harmonic poloidal Alfvén waves can be excited by drift-bounce resonance with energetic particle populations in the Earth's magnetosphere. Using a cold, ideal, MHD model, we study the temporal evolution of the resulting poloidal Alfvén waves. Imposing an azimuthal dependence of exp(i?y) in a ``box'' model of the magnetosphere, we describe poloidal waves, using a large azimuthal wavenumber ?. In homogeneous media, poloidally polarized waves simply oscillate in time. However, if these waves are excited in a nonuniform medium, we find that their polarization rotates from poloidal to toroidal in time. This polarization change is driven by magnetic field gradients which develop as the poloidal wave fields phase mix in time. Asymptotically, all the initial poloidal wave energy is ultimately transferred to a toroidal polarization. On the basis of this phase mixing we define a poloidal lifetime as the time taken for the poloidal and toroidal amplitudes to become equal. We find that the lifetime is given by ?=?/(d?A/dx). The irreversible change from a poloidal to a toroidal polarization is in agreement with early studies [Radoski, 1974] but contrary to a recent report [Ding et al., 1995]. Our results support the findings of Radoski. Consequently, poloidal Alfvén waves in the Earth's magnetosphere may have a finite poloidally polarized lifetime, after which they become dominantly toroidal, determined by their azimuthal wavenumber and the local natural Alfvén frequency gradient.

Mann, Ian R.; Wright, Andrew N.

1995-12-01

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 Theory in Semigroups Based on Intersectional Soft Sets  

PubMed Central

The notions of int-soft semigroups and int-soft left (resp., right) ideals are introduced, and several properties are investigated. Using these notions and the notion of inclusive set, characterizations of subsemigroups and left (resp., right) ideals are considered. Using the notion of int-soft products, characterizations of int-soft semigroups and int-soft left (resp., right) ideals are discussed. We prove that the soft intersection of int-soft left (resp., right) ideals (resp., int-soft semigroups) is also int-soft left (resp., right) ideals (resp., int-soft semigroups). The concept of int-soft quasi-ideals is also introduced, and characterization of a regular semigroup is discussed. PMID:25101310

Song, Seok Zun; Jun, Young Bae

2014-01-01

404

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

NASA Astrophysics Data System (ADS)

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

Gardiner, Crispin; Zoller, Peter

2014-03-01

405

GCSS Idealized Cirrus Model Comparison Project  

NASA Technical Reports Server (NTRS)

The GCSS Working Group on Cirrus Cloud Systems (WG2) is conducting a systematic comparison and evaluation of cirrus cloud models. This fundamental activity seeks to support the improvement of models used for climate simulation and numerical weather prediction through assessment and improvement of the "process" models underlying parametric treatments of cirrus cloud processes in large-scale models. The WG2 Idealized Cirrus Model Comparison Project is an initial comparison of cirrus cloud simulations by a variety of cloud models for a series of idealized situations with relatively simple initial conditions and forcing. The models (16) represent the state-of-the-art and include 3-dimensional large eddy simulation (LES) models, two-dimensional cloud resolving models (CRMs), and single column model (SCM) versions of GCMs. The model microphysical components are similarly varied, ranging from single-moment bulk (relative humidity) schemes to fully size-resolved (bin) treatments where ice crystal growth is explicitly calculated. Radiative processes are included in the physics package of each model. The baseline simulations include "warm" and "cold" cirrus cases where cloud top initially occurs at about -47C and -66C, respectively. All simulations are for nighttime conditions (no solar radiation) where the cloud is generated in an ice supersaturated layer, about 1 km in depth, with an ice pseudoadiabatic thermal stratification (neutral). Continuing cloud formation is forced via an imposed diabatic cooling representing a 3 cm/s uplift over a 4-hour time span followed by a 2-hour dissipation stage with no cooling. Variations of these baseline cases include no-radiation and stable-thermal-stratification cases. Preliminary results indicated the great importance of ice crystal fallout in determining even the gross cloud characteristics, such as average vertically-integrated ice water path (IWP). Significant inter-model differences were found. Ice water fall speed is directly related to the shape of the particle size distribution and the habits of the ice crystal population, whether assumed or explicitly calculated. In order to isolate the fall speed effect from that of the associated ice crystal population, simulations were also performed where ice water fall speed was set to the same constant value everywhere in each model. Values of 20 and 60 cm/s were assumed. Current results of the project will be described and implications will be drawn. In particular, this exercise is found to strongly focus the definition of issues resulting in observed inter-model differences and to suggest possible strategies for observational validation of the models. The next step in this project is to perform similar comparisons for well observed case studies with sufficient high quality data to adequately define model initiation and forcing specifications and to support quantitative validation of the results.

Starr, David OC.; Benedetti, Angela; Boehm, Matt; Brown, Philip R. A.; Gierens, Klaus; Girard, Eric; Giraud, Vincent; Jakob, Christian; Jensen, Eric; Khvorostyanov, Vitaly; Einaudi, Franco (Technical Monitor)

2000-01-01

406

A nearly ideal phosphor-converted white light-emitting diode  

NASA Astrophysics Data System (ADS)

A phosphor-converted light-emitting diode was obtained with nearly ideal blue-to-white conversion loss of only 1%. This is achieved using internal reflection to steer phosphor emission away from lossy surfaces, a reflector material with high reflectivity, and a remotely located organic phosphor having (1) unity quantum efficiency (?q), (2) homogeneous refractive index to minimize scattering, and (3) refractive index-matched to the encapsulation to eliminate total internal reflection. An inorganic composite phosphor is also reported with a nearly homogeneous refractive index to minimize diffuse scattering of emitted light, thereby maximizing the effective phosphor ?q and light extraction.

Allen, Steven C.; Steckl, Andrew J.

2008-04-01

407

Large ion Coulomb crystals: A near-ideal medium for coupling optical cavity modes to matter  

SciTech Connect

We present an investigation of the coherent coupling of various transverse field modes of an optical cavity to ion Coulomb crystals. The obtained experimental results, which include the demonstration of identical collective coupling rates for different transverse modes of a cavity field to ions in the same large Coulomb crystal, are in excellent agreement with theoretical predictions. The results furthermore suggest that Coulomb crystals in the future may serve as near-ideal media for high-fidelity multimode quantum information processing and communication purposes, including the generation and storage of single-photon qubits encoded in different transverse modes.

Dantan, A.; Albert, M.; Marler, J. P.; Herskind, P. F.; Drewsen, M. [QUANTOP, Danish National Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2009-10-15

408

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

409

Purification of noisy quantum measurements  

SciTech Connect

We consider the problem of improving noisy quantum measurements by suitable preprocessing strategies making many noisy detectors equivalent to a single ideal detector. For observables pertaining to finite-dimensional systems (e.g., qubits or spins) we consider preprocessing strategies that are reminiscent of quantum error correction procedures and allow one to perfectly measure an observable on a single quantum system for increasing number of inefficient detectors. For measurements of observables with an unbounded spectrum (e.g., photon number and homodyne and heterodyne detection), the purification of noisy quantum measurements can be achieved by preamplification as suggested by Yuen [Opt. Lett. 12, 789 (1987)].

Dall'Arno, Michele; D'Ariano, Giacomo Mauro [Quit Group, Dipartimento di Fisica 'A. Volta', via Bassi 6, I-27100 Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Gruppo IV, via Bassi 6, I-27100 Pavia (Italy); Sacchi, Massimiliano F. [Quit Group, Dipartimento di Fisica 'A. Volta', via Bassi 6, I-27100 Pavia (Italy); Istituto di Fotonica e Nanotecnologie (IFN-CNR), Piazza Leonardo da Vinci 32, I-20133 Milano (Italy)

2010-10-15

410

Volcanic Glass - an Ideal Recording Material?  

NASA Astrophysics Data System (ADS)

It has been suggested that volcanic glass is a perfect material for paleomagnetic research, especially for paleointensity studies, as it is often pristine and contains a magnetic fraction in the SD range. Furthermore, all biasing effects which are usually hard or impossible to detect in other recording media, are either absent or can be corrected for by using mineralogical and rock magnetic constraints. To verify this supposed ideal character, silicic volcanic glass from Pantelleria, Italy, from Tenerife, Spain, and from Mayor Island, New Zealand, was analyzed. Paleointensity measurements and rock magnetic experiments were conducted, including determinations of the anisotropy of thermoremanence. Structural properties of volcanic glass, particularly the glass transition and the natural cooling rate across this transition were investigated by relaxation geospeedometry. By additionally determining the magnetic cooling rate dependency of the thermoremanence, a correction of paleointensity data for cooling rate effects could be applied. Samples from Pantelleria and Mayor Island show very low NRM intensities, hampering rock magnetic measurements. Nevertheless, paleointensity results (~40~?T) were obtained for 50% of the Pantelleria samples though the scatter is remarkable (30 to 50~?T). Intensity measurements of almost all Mayor Island samples agree very well and yield a paleointensity of ~55~?T. Anisotropy and cooling rate corrections for Pantelleria and Mayor Island could not be applied. The glass transition of these samples is close to their blocking temperature spectra. Thus, during repeated heating to higher temperature the samples enter the transition interval and alter. The reasons and consequences of this alteration are investigated. NRM intensities are much larger for Tenerife samples. Rock magnetic experiments indicate low Ti- or even pure Magnetite in the SD range. Very high success rates for paleointensity experiments are observed. An application of anisotropy and cooling rate corrections is possible as glass transition temperatures are well above the magnetic blocking temperature. High success rates and well defined paleointensity data, accompanied by the possibility to apply reliability tests and corrections, support the high suitability of silicic volcanic glass for paleomagnetic measurements.

Ferk, A.; Leonhardt, R.; Richard, D.; v. Aulock, F.; Hess, K.; Dingwell, D.

2008-12-01

411

Dynamic modeling of gas springs  

NASA Astrophysics Data System (ADS)

Linear dynamic modeling of gas springs is important for the basic design of free piston Stirling engines. The conventional gas spring model, a dashpot in parallel with an ideal spring, gives poor prediction of gas spring performance. The anelastic model consists of two parallel springs, one of which is in series with a dashpot. With proper selection of spring and damping constants it gives improved prediction of gas spring dynamics. A linear gas spring model that appears to be superior to those currently used is proposed.

Kornhauser, A. A.

412

Unconditional Room Temperature Quantum Memory  

E-print Network

Just as classical information systems require buffers and memory, the same is true for quantum information systems. The potential that optical quantum information processing holds for revolutionising computation and communication is therefore driving significant research into developing optical quantum memory. A practical optical quantum memory must be able to store and recall quantum states on demand with high efficiency and low noise. Ideally, the platform for the memory would also be simple and inexpensive. Here, we present a complete tomographic reconstruction of quantum states that have been stored in the ground states of rubidium in a vapour cell operating at around 80$^o$C. Without conditional measurements, we show recall fidelity up to 98% for coherent pulses containing around one photon. In order to unambiguously verify that our memory beats the quantum no-cloning limit we employ state independent verification using conditional variance and signal transfer coefficients.

M. Hosseini; G. Campbell; B. M. Sparkes; P. K. Lam; B. C. Buchler

2014-12-29

413

Integral closures of ideals and rings Irena Swanson  

E-print Network

Integral closures of ideals and rings Irena Swanson ICTP, Trieste School on Local Rings and Local Theorem, completions). In the first lecture I will present the basics of integral closure with very few material. Table of contents: Section 1: Integral closure of rings and ideals 1 Section 2: Integral closure

Swanson, Irena

414

Relationship Between Pattern of Achievement and Self-Ideal Congruence.  

ERIC Educational Resources Information Center

This study investigates the relationship between pattern of achievement and self-ideal congruence of 408 ninth grade boys and girls. Underachievers, average achievers and overachievers were determined on the basis of whether their final average marks were higher or lower than had been predicted. Prediction criteria are presented. Self-ideal

Gill, Mohindra P.

415

ASYMPTOTIC MULTIPLICITIES OF GRADED FAMILIES OF IDEALS AND LINEAR SERIES  

E-print Network

. Introduction 1.1. Limits of graded families of ideals. In this paper we prove the following theorem about graded families of mR-primary ideals. Theorem 1.1. (Theorem 5.5) Suppose that R is a local ring in a regular local ring such that the above limit is irrational. The problem of existence of such limits (1

Cutkosky, Dale

416

Idealization and Communication in Long-Distance Premarital Relationships.  

ERIC Educational Resources Information Center

Explored the phenomenon of idealization in college premarital long-distance relationships. Analyzed questionnaire responses of 71 college couples. Findings indicated long-distance couples had more restricted communication and were more idealized than their geographically close counterparts. Found an associative pattern between restricted…

Stafford, Laura; Reske, James R.

1990-01-01

417

Ideal landscapes - landscape design between beauty and meaning  

Microsoft Academic Search

In this article I deal with the quest for beauty that I have found has very much to do with meaning. Instead of using the concept of beauty I introduce a concept that I call ideal landscape. This concept stands for what my clients often call beauty but that I through practice have found is about something else. The ideal

Carola Wingren

418

Idealizing Ion Channel Recordings by a Jump Segmentation Multiresolution Filter  

E-print Network

1 Idealizing Ion Channel Recordings by a Jump Segmentation Multiresolution Filter Thomas Hotz, Ole data, a new approach called J-SMURF to idealize ion channel recordings has been developed. It is model on simulations as well as on ion current traces obtained from gramicidin A channels reconstituted into solvent

Munk, Axel

419

Academic Deans' Perceptions of Current and Ideal Curriculum Emphases.  

ERIC Educational Resources Information Center

A survey of 57 dental school deans concerning current and ideal curricular emphases in 33 topic areas identified three that were rated highly as ideals: health promotion/disease prevention; primary care; and effective patient-provider relationships/communication. The most significant barrier to reform was an already crowded curriculum. Deans…

Graber, David R.; O'Neil, Edward H.; Bellack, Janis P.; Musham, Catherine; Javed, Tariq

1998-01-01

420

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

421

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

422

Non-ideal Effects in Streaming Bi-Dust Acoustic Instability  

SciTech Connect

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

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

2006-12-04

423

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

424

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

425

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

426

Quantum Gibbs ensemble Monte Carlo  

E-print Network

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 $^4$He in two dimensions.

Riccardo Fantoni; Saverio Moroni

2014-08-24

427

Quantum Formalism: Brief Epistemological Considerations  

E-print Network

We argue about a conceptual approach to quantum formalism. Starting from philosophical conjectures (Platonism, Idealism and Realism) as basic ontic elements (namely: math world, data world, and state of matter), we will analyze the quantum superposition principle. This analysis bring us to demonstrate that the basic assumptions affect in different ways:(a) the general problem of the information and computability about a system, (b) the nature of the math tool utilized and (c) the correspondent physical reality.

Helen Lynn; Michele Caponigro

2006-10-26

428

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

429

Modeling, analysis and control of quantum electronic devices  

E-print Network

- or ac-SQUID . . . . . . . . . . . . . . . . . . . . . 66 4. dc-SQUID . . . . . . . . . . . . . . . . . . . . . . . . 67 D. Superconducting circuits: quantum . . . . . . . . . . . . . 70 vii CHAPTER Page E. Quantum gates... design for Shor?s algorithm . . . . . . . . . . . 44 3. Experimental result . . . . . . . . . . . . . . . . . . . 46 E. Quantum algorithm for lattice-gas systems . . . . . . . . . 47 1. Quantum algorithm for a lattice-gas model . . . . . . 49 2. Physical...

Zhang, Zhigang

2009-06-02

430

Quantum Dot Modulators  

Microsoft Academic Search

Mach-zender devices are an ideal modulation source for communication networks at 1.3 mum and 1.55 mum. Superlinear electro-optical effects are a desirable feature in mach-zender modulators since their large second order electro-optical coefficient would give complete signal extinction at a small voltage. Quantum dot devices show promise for such applications in the 1.3 mum band. In this project we performed

Brendan Turner; Manish Mehta; Ramesh Laghumavarapu; Diana Huffaker

2006-01-01

431

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

432

Effects of Static Imperfections for Quantum Computing  

Microsoft Academic Search

We model the quantum computer hardware as a two-dimensional lattice of qubits with static imperfections, i.e. fluctuations in individual qubit energies and residual short-range inter-qubit couplings. We show that these imperfections can lead to the emergence of quantum chaos and dynamical thermalization also in a quantum computer ideally decoupled from the environment. We discuss their effect on the stability of

Giuliano Benenti; Giulio Casati

2003-01-01

433

Numerical computation for teaching quantum statistics  

NASA Astrophysics Data System (ADS)

The study of ideal quantum gases reveals surprising quantum effects that can be observed in macroscopic systems. The properties of bosons are particularly unusual because a macroscopic number of particles can occupy a single quantum state. We describe a computational approach that supplements the usual analytic derivations applicable in the thermodynamic limit. The approach involves directly summing over the quantum states for finite systems and avoids the need for doing difficult integrals. The results display the unusual behavior of quantum gases even for relatively small systems.

Price, Tyson; Swendsen, Robert H.

2013-11-01

434

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, resulting in huge potential in quantum network and quantum computation. 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

435

Partially Flat Ideal Triangulations of Cusped Hyperbolic 3Manifolds  

E-print Network

tetrahedra in H 3 glued along faces. Since then, ideal triangulations have become an important instrument to standard spines, which exist by [4]. Let ø consist of n tetrahedra. Then, using the combinatorial data

Petronio, Carlo

436

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

437

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

438

Robot task planning in a non-ideal blocks world  

E-print Network

ROBOT TASK PLANNING IN A NON-IDEAL BLOCKS WORLD A Thesis by VASUDEV RANGADASS Submitted to the Graduate College Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1988 Major Subject...: Computer Science ROBOT TASK PLANNING IN A NON-IDEAL BLOCKS WORLD A Thesis by VASUDEV RANGADASS Approved as to style and content by: Amitabha Mu ee (Chairman of Committee) Glen Williams (Member) Arun Sen (Member) Glen Williams (Head...

Rangadass, Vasudev

2012-06-07

439

Operations on fuzzy ideals of $\\Gamma$-semirings  

E-print Network

The purpose of this paper is to introduce different types of operations on fuzzy ideals of $\\Gamma$-semirings and to prove subsequently that these oprations give rise to different structures such as complete lattice, modular lattice on some restricted class of fuzzy ideals of $\\Gamma$-semirings. A characterization of a regular $\\Gamma$-semiring has also been obtained in terms of fuzzy subsets.

Dutta, T K; Goswami, Sarbani

2011-01-01

440

Ideal spiral bevel gears: A new approach to surface geometry  

NASA Technical Reports Server (NTRS)

The fundamental geometrical characteristics of spiral bevel gear tooth surfaces are discussed. The parametric representation of an ideal spiral bevel tooth is developed based on the elements of involute geometry, differential geometry, and fundamental gearing kinematics. A foundation is provided for the study of nonideal gears and the effects of deviations from ideal geometry on the contact stresses, lubrication, wear, fatigue life, and gearing kinematics.

Huston, R. L.; Coy, J. J.

1980-01-01

441

Quantum non-locality, causality and mistrustful cryptography Muhammad Nadeem  

E-print Network

considered to be impossible. (iv) the two-party computation turns out to be asynchronous ideal coin tossing bit commitment. Finally, we conjecture here that the combination of quantum non-locality and theory-bias coin tossing38 . Moreover, asynchronous ideal coin tossing is impossible in I #12;2 classical

442

Existence of equilibria in quantum Bertrand-Edgeworth duopoly game  

NASA Astrophysics Data System (ADS)

Both classical and quantum version of two models of price competition in duopoly market, the one is realistic and the other is idealized, are investigated. The pure strategy Nash equilibria of the realistic model exists under stricter condition than that of the idealized one in the classical form game. This is the problem known as Edgeworth paradox in economics. In the quantum form game, however, the former converges to the latter as the measure of entanglement goes to infinity.

Sekiguchi, Yohei; Sakahara, Kiri; Sato, Takashi

2012-12-01

443

Lecture notes on thermodynamics of ideal string gases and its application in cosmology  

E-print Network

In these lecture notes I give a pedagogical introduction to the thermodynamics of ideal string gases. The computation of thermodynamic quantities in the canonical ensemble formalism will be shown in detail with explicit examples. Attention will be given mainly to the thermodynamical consequences of string degrees of freedom, where I will especially address i) the Hagedorn temperature, a critical temperature above which the canonical ensemble description breaks down, which can be the onset point of some instability of the string gas; ii) the phase structure arising from compactification, embodied in the moduli-dependence of the Helmholtz free energy, which corrects the tree-level vacuum and can provide mechanism for moduli stabilization. Then I will briefly explain the implementation of string gas thermodynamics in cosmology, showing a simple example which gives rise to a radiation-dominated early universe. Further phenomenological issues and open questions will be discussed qualitatively with references indic...

Liu, Lihui

2014-01-01

444

Ideal response function of a 3He proportional counter to thermal neutrons determined by different length counters  

NASA Astrophysics Data System (ADS)

The gas multiplication distributions along the anode wires of 3He proportional counters with different sensitive lengths of 10, 15 and 20 cm were measured using a collimated thermal neutron beam at the Kyoto University Reactor facility. The ideal response function excluding the effect of electric field distortion near the boundaries of the anode wire was derived by taking into account the difference between pulse height spectra measured by two different length counters. The pulse height spectrum calculated by the NRESPG Monte Carlo code assuming the ideal gas multiplication region showed relatively good agreement with the response function derived from the measurements. Both the energy resolution of the full energy peak at 764 keV and the peak ratio to the entire pulse height spectrum were improved markedly.

Kudo, K.; Takeda, N.; Uritani, A.; Koshikawa, S.; Shibata, Y.; Kobayashi, K.; Yoshimoto, T.

2004-01-01

445

Two Lighthouses to Navigate: Effects of Ideal and Counter-Ideal Values on Follower Identification and Satisfaction with Their Leaders  

Microsoft Academic Search

Ideals (or ideal values) help people to navigate in social life. They indicate at a very fundamental level what people are\\u000a concerned about, what they strive for, and what they want to be affiliated with. Transferring this to a leader–follower analysis,\\u000a our first study (n = 306) confirms that followers’ identification and satisfaction with their leaders are stronger, the more leaders match

Niels van Quaquebeke; Rudolf Kerschreiter; Alice E. Buxton; Rolf van Dick

2010-01-01

446

Entropy flow in near-critical quantum circuits  

Microsoft Academic Search

Near-critical quantum circuits are ideal physical systems for asymptotically large-scale quantum computers, because their low energy collective excitations evolve reversibly, effectively isolated from the environment. The design of reversible computers is constrained by the laws governing entropy flow within the computer. In near-critical quantum circuits, entropy flows as a locally conserved quantum current, obeying circuit laws analogous to the electric

Daniel Friedan

2005-01-01

447

Indirect exchange between magnetic impurities via the inhomogeneous electron gas in a ? symmetric double quantum well under a longitudinal electric field  

Microsoft Academic Search

The indirect interaction between two magnetic impurities in a 0268-1242\\/12\\/12\\/008\\/img8 double quantum well under a strong electric field perpendicular to the interfaces is obtained as a function of the field strength and the barrier width. We show that, if a single state is bound to the well, the exchange energy factorizes as a form factor depending on the quantum well

L. G. Ferreira Filho; I. C. da Cunha Lima; A. Troper

1997-01-01

448

Developmental Idealism and Cultural Models of the Family in Malawi.  

PubMed

This paper examines the extent to which developmental idealism has been disseminated in Malawi. Developmental idealism is a set of beliefs and values about development and the relationships between development and family structures and behavior. Developmental idealism states that attributes of societies and families defined as modern are better than attributes defined as traditional, that modern societies help produce modern families, that modern families facilitate the achievement of modern societies, and that the future will bring family change in the direction of modernity. Previous research has demonstrated that knowledge of developmental idealism is widespread in many places around the world, but provides little systematic data about it in sub-Saharan Africa or how knowledge of it is associated with certain demographic characteristics in that region. In this paper, we address this issue by examining whether ordinary people in two settings in Malawi, a sub-Saharan African country, have received and understood messages that are intended to associate development with certain types of family forms and family behaviors. We then examine associations between demographic characteristics and developmental idealism to investigate possible mechanisms linking global discourse about development to the grassroots. We analyze data collected in face-to-face surveys from two samples of Malawian men in 2009 and 2010, one rural, the other in a low-to-medium income neighborhood of a city. Our analysis of these survey data shows considerable evidence that many developmental idealism beliefs have been spread in that country and that education has positive effects on beliefs in the association between development and family attributes. We also find higher levels of developmental idealism awareness in the urban sample than we do in the rural sample, but once dissimilarities in education and wealth between the two samples are controlled, awareness levels no longer differed between urban and rural respondents. We explore how these beliefs intersect with longstanding local values and beliefs in Malawi. PMID:25197155

Thornton, Arland; Pierotti, Rachael S; Young-DeMarco, Linda; Watkins, Susan

2014-10-01

449

Influence of non-ideality on aerosol growth  

NASA Astrophysics Data System (ADS)

Secondary organic aerosol (SOA) is a complex mixture of water and organic molecules. Its composition is determined by the presence of semi-volatile or non-volatile compounds, their vapor pressure and activity coefficient. The activity coefficient is a non-ideality effect and is a complex function of SOA composition. In a previous publication, the detailed chemical mechanism (DCM) for ?-pinene oxidation and subsequent aerosol formation BOREAM was presented. In this work, we investigate with this DCM the impact of non-ideality by simulating smog chamber experiments for ?-pinene degradation and aerosol formation. Several versions of the UNIFAC method are tested for this purpose, and missing parameters for e.g. hydroperoxides and nitrates are inferred from fittings to activity coefficient data generated using the SPARC model. It turns out that for most experiments, non-ideality has only a limited impact on the interaction between the organic molecules, and therefore on SOA yields and composition, when water uptake is ignored. Still, for ozonolysis experiments with low amounts of volatile organic carbon (low-VOC), the UNIFAC parameterization of Raatikainen et al. leads to significantly higher SOA yields (by up to a factor 1.6) compared to the ideal case and to other parameterizations. Water uptake is model dependent, in the order: ideal>UNIFAC-Raatikainen>UNIFAC-Peng>UNIFAC-Hansen?UNIFAC-Magnussen?UNIFAC-Ming. In the absence of salt dissolution, phase splitting from pure SOA is unlikely.

Compernolle, S.; Ceulemans, K.; Müller, J.-F.

2008-09-01

450

Optimal control of quantum revival  

E-print Network

Increasing fidelity is the ultimate challenge of quantum information technology. In addition to decoherence and dissipation, fidelity is affected by internal imperfections such as impurities in the system. Here we show that the quality of quantum revival, i.e., periodic recurrence in the time evolution, can be restored almost completely by coupling the distorted system to an external field obtained from quantum optimal control theory. We demonstrate the procedure with wave-packet calculations in both one- and two-dimensional quantum wells, and analyze the required physical characteristics of the control field. Our results generally show that the inherent dynamics of a quantum system can be idealized at an extremely low cost.

E. Rasanen; E. J. Heller

2012-11-05

451

Quantifying ataxia: ideal trajectory analysis--a technical note  

NASA Technical Reports Server (NTRS)

We describe a quantitative method to assess repeated stair stepping stability. In both the mediolateral (ML) and anterioposterior (AP) directions, the trajectory of the subject's center of mass (COM) was compared to an ideal sinusoid. The two identified sinusoids were unique in each direction but coupled. Two dimensionless numbers-the mediolateral instability index (IML) and AP instability index (IAP)-were calculated using the COM trajectory and ideal sinusoids for each subject with larger index values resulting from less stable performance. The COM trajectories of nine nonimpaired controls and six patients diagnosed with unilateral or bilateral vestibular labyrinth hypofunction were analyzed. The average IML and IAP values of labyrinth disorder patients were respectively 127% and 119% greater than those of controls (p<0.014 and 0.006, respectively), indicating that the ideal trajectory analysis distinguishes persons with labyrinth disorder from those without. The COM trajectories also identify movement inefficiencies attributable to vestibulopathy.

McPartland, M. D.; Krebs, D. E.; Wall, C. 3rd

2000-01-01

452

Body ideals for heterosexual romantic partners: Gender and sociocultural influences.  

PubMed

In the present study, heterosexual college women (N=327) and men (N=160) were asked about their body type preferences for (hypothetical) romantic partners. Participants chose a particular silhouette value as ideal for a romantic partner, and rated how important it was to them for their partner to have this ideal body type. Men placed more importance on the body silhouette they chose for a partner than women did, and men's importance ratings were positively associated with the rated sexual permissiveness of their peer group and their total media use. Consuming sports media and watching reality television were the best media predictors of men's judgments about women's bodies. Less variability was explained in women's preferences for men partners' bodies, but endorsing adversarial sexual attitudes was positively related to judging the ideals chosen for men's bodies as important. Results were interpreted within both evolutionary and sociocultural theoretical frameworks. PMID:25462878

Murnen, Sarah K; Poinsatte, Katherine; Huntsman, Karen; Goldfarb, Jesse; Glaser, Daniel

2014-10-17

453

Reported Effects of Masculine Ideals on Gay Men  

PubMed Central

This exploratory study used consensual qualitative research methodology (Hill et al., 2005) to analyze what gay men associate with masculinity and femininity, how they feel masculine ideals affect their self-image, and how masculine ideals affect their same-sex relationships. Written responses were collected from 547 self-identified gay men in the U.S. via an Internet-based survey. Findings supported previous reports that perceptions of gender roles among gay men appear based on masculine and feminine stereotypes. Additionally, more adverse versus positive effects on self-image and same-sex romantic relationships were reported including difficulty being emotional and affectionate, pressure to be physically attractive, and pressure to appear masculine in order to be accepted by society and to be seen as desirable by other gay men. While research on gay men’s experience with masculinity continues, psychologists should consider the possible influence of traditional masculine ideals when conceptualizing their gay male clients. PMID:20628534

Sánchez, Francisco J.; Greenberg, Stefanie T.; Liu, William Ming; Vilain, Eric

2010-01-01

454

Approaching the ideal elastic limit of metallic glasses  

PubMed Central

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 metallic glasses, however, the ideal elastic limit remains poorly characterized and understood. Here we show that the elastic strain limit and the corresponding strength of submicron-sized metallic glass specimens are about twice as high as the already impressive elastic limit observed in bulk metallic glass samples, in line with model predictions of the ideal elastic limit of metallic glasses. We achieve this by employing an in situ transmission electron microscope tensile deformation technique. Furthermore, we propose an alternative mechanism for the apparent 'work hardening' behaviour observed in the tensile stress–strain curves. PMID:22215084

Tian, Lin; Cheng, Yong-Qiang; Shan, Zhi-Wei; Li, Ju; Wang, Cheng-Cai; Han, Xiao-Dong; Sun, Jun; Ma, Evan

2012-01-01

455

Gas Chromatography  

NASA Astrophysics Data System (ADS)

Gas chromatography (GC) has many applications in the analysis of food products. GC has been used for the determination of fatty acids, triglycerides, cholesterol, gases, water, alcohols, pesticides, flavor compounds, and many more. While GC has been used for other food components such as sugars, oligosaccharides, amino acids, peptides, and vitamins, these substances are more suited to analysis by high performance liquid chromatography. GC is ideally suited to the analysis of volatile substances that are thermally stable. Substances such as pesticides and flavor compounds that meet these criteria can be isolated from a food and directly injected into the GC. For compounds that are thermally unstable, too low in volatility, or yield poor chromatographic separation due to polarity, a derivatization step must be done before GC analysis. The two parts of the experiment described here include the analysis of alcohols that requires no derivatization step, and the analysis of fatty acids which requires derivatization. The experiments specify the use of capillary columns, but the first experiment includes conditions for a packed column.

Qian, Michael C.

456

Optimum Anthropometric Criteria for Ideal Body Composition Related Fitness  

PubMed Central

Objectives The three aims of this study were to establish equations for ideal body composition related fitness to be used by adults willing to gain optimum body composition related fitness; to predict the possible symmetrical major muscle circumference, and to compute the ideal body fat percentage (BFP) with ideal body weight (IBW) based on the body mass index (BMI). Methods Twenty-four athletes were intentionally selected, with heights of 166–190 cm and aged 20–42 years, according to a judging committee that used modified International Fitness Federation criteria for the Mr. Fitness competition “super body category”. Common anthropometric and body composition measurements were taken for the following independent variables: body height, upper limb length, lower limb length, thigh length, arm length, shoulder width, forearm length, shank length, and wrist girth; and for the following dependent variables: circumferences of shoulder, thigh, waist, hip, chest, biceps, forearm, shank, and neck. Skin fold thickness was measured at three sites by a Harpenden caliper to calculate BFP. Results The findings indicate that there was a predictive correlation between major independent variables and body circumferences. The mean range used to find out the ideal BFP percentage which was 5.6–6.7 %. The BMI equation used to find the IBW was H2 × 23.77 ± 2 SE. Stepwise multiple regressions were also used to derive predictive equations. The most predictive independent variables were wrist girth and height. Conclusion It is suggested that the above equations, the ideal BFP percentage and the IBW be used as criteria in training sessions to achieve ideal body composition related fitness. PMID:21509084

Kilani, Hashem; Abu-Eisheh, Asem

2010-01-01

457

PLANETESIMAL AND PROTOPLANET DYNAMICS IN A TURBULENT PROTOPLANETARY DISK: IDEAL STRATIFIED DISKS  

SciTech Connect

Due to the gravitational influence of density fluctuations driven by magneto-rotational instability in the gas disk, planetesimals and protoplanets undergo diffusive radial migration as well as changes in other orbital properties. The magnitude of the effect on particle orbits can have important consequences for planet formation scenarios. We use the local-shearing-box approximation to simulate an ideal, isothermal, magnetized gas disk with vertical density stratification and simultaneously evolve numerous massless particles moving under the gravitational field of the gas and the host star. We measure the evolution of the particle orbital properties, including mean radius, eccentricity, inclination, and velocity dispersion, and its dependence on the disk properties and the particle initial conditions. Although the results converge with resolution for fixed box dimensions, we find the response of the particles to the gravity of the turbulent gas correlates with the horizontal box size, up to 16 disk scale heights. This correlation indicates that caution should be exercised when interpreting local-shearing-box models involving gravitational physics of magneto-rotational turbulence. Based on heuristic arguments, nevertheless, the criterion L{sub h} /R {approx} O(1), where L{sub h} is the horizontal box size and R is the distance to the host star, is proposed to possibly circumvent this conundrum. If this criterion holds, we can still conclude that magneto-rotational turbulence seems likely to be ineffective at driving either diffusive migration or collisional erosion under most circumstances.

Yang, Chao-Chin [Department of Astronomy, University of Illinois, Urbana, IL 61801 (United States); Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, New York, NY 10024 (United States); Menou, Kristen, E-mail: ccyang@ucolick.org, E-mail: mordecai@amnh.org, E-mail: kristen@astro.columbia.edu [Department of Astronomy, Columbia University, New York, NY 10027 (United States)

2012-04-01

458

Ionization Chemistry and Role of Grains on Non-ideal MHD Effects in Protoplanetary Disks  

NASA Astrophysics Data System (ADS)

Ionization in protoplanetary disks (PPDs) is one of the key elements for understanding disk chemistry. It also determines the coupling between gas and magnetic fields hence strongly affect PPD gas dynamics. We study the ionization chemistry in the presence of grains in the midplane region of PPDs and its impact on gas conductivity reflected in non-ideal MHD effects including Ohmic resistivity, Hall effect and ambipolar diffusion. We first develop a reduced chemical reaction network from the UMIST database. The reduced network contains much smaller number of species and reactions while yields reliable estimates of the disk ionization level compared with the full network. We further show that grains are likely the dominant charge carrier in the midplane regions of the inner disk, which significantly affects the gas conductivity. In particular, ambipolar diffusion is strongly reduced and the Hall coefficient changes sign in the presence of strong magnetic field. The latter provides a natural mechanism to the saturation of the Hall-shear instability.

Xu, Rui; Bai, Xue-Ning; Oberg, Karin I.

2015-01-01

459

The Casimir force between an ideal metal plate and a dissipative dielectric slab  

NASA Astrophysics Data System (ADS)

In this research, a general formula for the Casimir force between ideal metal plate and a dissipative dielectric slab has been obtained. The dielectric function of the slab is assumed to be an arbitrary complex function of frequency satisfying Kramers-Kronig relations. A classical expression for the radiation pressure of the vacuum fields on the slab is presented by using the Maxwell stress tensor. With the transition to the quantum domain and using the fluctuation dissipation theorem and Kubo's formula, the resulting expression is written in terms of the imaginary part of the vector potential Green functions components of the system. Finally, by computing the Green function, the Casimir force on the slab is obtained. This formalism enables us to calculate the Casimir force without resorting to the explicit form of the field operators. The general expression is confirmed by limiting and comparing with one of the previous works.

Falinejad, H.; Bayat, F.

2014-09-01

460

Complementary construction of ideal nonimaging concentrators and its applications.  

PubMed

A construction principle for ideal nonimaging concentrators based on the complementary edge rays outside the nominal field of view is presented, with illustrations for the trumpet, compound parabolic concentrator, and compound hyperbolic concentrator. A simple string construction for the trumpet concentrator is shown to follow from this observation-the trumpet having been the one ideal concentrator for which no string-construction method had previously been noted. An application of these observations for solar concentrator design when nonisothermal receivers are advantageous is also presented. PMID:21127575

Gordon, J M

1996-10-01

461

Complementary construction of ideal nonimaging concentrators and its applications  

NASA Astrophysics Data System (ADS)

A construction principle for ideal nonimaging concentrators based on the complementary edge rays outside the nominal field of view is presented, with illustrations for the trumpet, compound parabolic concentrator, and compound hyperbolic concentrator. A simple string construction for the trumpet concentrator is shown to follow from this observation-the trumpet having been the one ideal concentrator for which no string-construction method had previously been noted. An application of these observations for solar concentrator design when nonisothermal receivers are advantageous is also presented.

Gordon, J. M.

1996-10-01

462

On the Rees algebra of certain codimension two perfect ideals  

Microsoft Academic Search

.  ?Suppose ? is a set of arbitrary number of smooth points in ?2\\u000a \\u000a its defining ideal. In this paper, we study the Rees algebras of the ideals generated by I\\u000a \\u000a \\u000a \\u000a t\\u000a \\u000a \\u000a \\u000a , t ??. When the points of ? are general, we give a set of defining equations for the Rees algebra . When the points of ? are arbitrary,

Hà Huy Tài

2002-01-01

463

Kinetic modeling of non-ideal explosives with CHEETAH  

SciTech Connect

We report an implementation of the Wood-Kirkwood kinetic detonation model based on multi-species equations of state and multiple reaction rate laws. Finite rate laws are used for the slowest chemical reactions. Other reactions are given infinite rates and are kept in constant thermodynamic equilibrium. We model a wide range of ideal and non-ideal composite energetic materials. We find that we can replicate experimental detonation velocities to within a few per cent, while obtaining good agreement with estimated reaction zone lengths. The detonation velocity as a function of charge radius is also correctly reproduced.

Fried, L E; Howard, W M; Souers, P C

1998-08-06

464

Statistical characterization of the interchange-instability spectrum of a separable ideal-magnetohydrodynamic model system  

NASA Astrophysics Data System (ADS)

A Suydam-unstable circular cylinder of plasma with periodic boundary conditions in the axial direction is studied within the approximation of linearized ideal magnetohydrodynamics (MHD). The normal mode equations are completely separable, so both the toroidal Fourier harmonic index n and the poloidal index m are good quantum numbers. The full spectrum of eigenvalues in the range 1?m?mmax is analyzed quantitatively, using asymptotics for large m , numerics for all m , and graphics for qualitative understanding. The density of eigenvalues scales like mmax2 as mmax?? . Because finite- m corrections scale as 1/mmax2 , their inclusion is essential in order to obtain the correct statistics for the distribution of eigenvalues. Near the largest growth rate, only a single radial eigenmode contributes to the spectrum, so the eigenvalues there depend only on m and n as in a two-dimensional system. However, unlike the generic separable two-dimensional system, the statistics of the ideal-MHD spectrum departs somewhat from the Poisson distribution, even for arbitrarily large mmax . This departure from Poissonian statistics may be understood qualitatively from the nature of the distribution of rational numbers in the rotational transform profile.

Dewar, R. L.; Tatsuno, T.; Yoshida, Z.; Nührenberg, C.; McMillan, B. F.

2004-12-01

465

Statistical characterization of the interchange-instability spectrum of a separable ideal-magnetohydrodynamic model system  

SciTech Connect

A Suydam-unstable circular cylinder of plasma with periodic boundary conditions in the axial direction is studied within the approximation of linearized ideal magnetohydrodynamics (MHD). The normal mode equations are completely separable, so both the toroidal Fourier harmonic index n and the poloidal index m are good quantum numbers. The full spectrum of eigenvalues in the range 1{<=}m{<=}m{sub max} is analyzed quantitatively, using asymptotics for large m, numerics for all m, and graphics for qualitative understanding. The density of eigenvalues scales like m{sub max}{sup 2} as m{sub max}{yields}{infinity}. Because finite-m corrections scale as 1/m{sub max}{sup 2}, their inclusion is essential in order to obtain the correct statistics for the distribution of eigenvalues. Near the largest growth rate, only a single radial eigenmode contributes to the spectrum, so the eigenvalues there depend only on m and n as in a two-dimensional system. However, unlike the generic separable two-dimensional system, the statistics of the ideal-MHD spectrum departs somewhat from the Poisson distribution, even for arbitrarily large m{sub max}. This departure from Poissonian statistics may be understood qualitatively from the nature of the distribution of rational numbers in the rotational transform profile.

Dewar, R.L. [Department of Theoretical Physics and Plasma Research Laboratory, Research School of Physical Sciences and Engineering, Australian National University, ACT 0200 (Australia); Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8651 (Japan); Tatsuno, T. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States); Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8651 (Japan); Yoshida, Z. [Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8651 (Japan); Nuehrenberg, C. [Max-Planck-Institut fuer Plasma Physik, Teilinstitut Greifswald, D-17491 (Germany); McMillan, B.F. [Department of Theoretical Physics and Plasma Research Laboratory, Research School of Physical Sciences and Engineering, Australian National University, ACT 0200 (Australia)

2004-12-01

466

Possible ''new'' quantum systems  

Microsoft Academic Search

Systems of spin-aligned hydrogen isotopes are studied. They are shown to exhibit even more extreme ''quantum'' behavior than the helium isotopes. Spin-aligned hydrogen is predicted to be a gas at all temperatures and its Bose-Einstein condensation and possible superfluidity are discussed. Spin-aligned deuterium is predicted to show critical behavior strongly influence by quantum mechanics. The preparation of spin-aligned hydrogen (in

Willian Stwalley; L. H. Nosanow

1976-01-01

467

Quantum Computers and Quantum Control  

Microsoft Academic Search

Quantum computation is an excercise in quantum control: for a quantum system to compute, its dynamics must be controlled to a high degree of precision. Quantum control, in turn, is an excercise in quantum computation: control can be thought of in terms of how information is represented and processed. This talk reviews recent developments in quantum computation and quantum control

Seth Lloyd

2001-01-01

468

Experimental implementation of a nonthermalizing quantum thermometer  

NASA Astrophysics Data System (ADS)

Based on a quantum interferometric circuit, we implement a NMR quantum thermometer, in which a probe qubit measures the temperature of a nuclear spin at thermal equilibrium with a bath. The whole procedure lasts 5.5 ms, a much shorter time than the probe's spin-lattice relaxation time, which is . The fidelity of the probe final quantum state, in respect to the ideal theoretical prediction, is above 99 %. We show that quantum coherence is essential for the high fidelity of temperature measurement. We discuss the source of errors on the temperature measurement and some possible applications of the thermometer.

Raitz, C.; Souza, A. M.; Auccaise, R.; Sarthour, R. S.; Oliveira, I. S.

2015-01-01

469

Quantum physics: An atomic SQUID  

NASA Astrophysics Data System (ADS)

Superconducting quantum circuits are the core technology behind the most sensitive magnetometers. An analogous device has now been implemented using a gas of ultracold atoms, with possible applications for rotation sensing.

Sackett, Charles A.

2014-01-01

470

Be Very Afraid: Cyborg Athlete, Transhuman Ideals & Posthumanity  

Microsoft Academic Search

This paper argues that transhumanism lacks persuasiveness because its futurological underpinnings are met with skepticism, not due to a lack of applicability, but for the lack of clarity about how transhumanity can become manifest within a cautious technological society. It is considered that the integration of transhuman ideals within social praxis is problematic in a variety of social contexts, but

Andy Miah

2004-01-01

471

Idealized Visions from behind Bars: Prisoners' Perspectives on School Change  

ERIC Educational Resources Information Center

This article presents findings of a qualitative exploration of prisoners' perspectives on ideal schools. Based on the foundation of systems theory, it suggests that many voices are unheard in the school reform dialogue. The results of interviews with maximum-security prisoners pointed to a need for increased relationships among teachers and…

Carr-Chellman, Alison A.; Beabout, Brian; Almeida, Louis; Gursoy, Hursa

2009-01-01

472

Idealized Visions from Outside: Homeless Perspectives on School Change  

ERIC Educational Resources Information Center

This article presents findings from a qualitative exploration of homeless individuals' experiences and their perspectives on ideal designs of schools. The article is part of a larger research project titled "Unheard Voices," which explores marginalized individuals' (homeless, prisoners, working poor, and migrant workers)…

Magolis, David; Carr-Chellman, Alison A.

2013-01-01

473

Ideal Weight and Weight Satisfaction: Association With Health Practices  

PubMed Central

Evidence suggests that individuals have become more tolerant of higher body weights over time. To investigate this issue further, the authors examined cross-sectional associations among ideal weight, examination year, and obesity as well as the association of ideal weight and body weight satisfaction with health practices among 15,221 men and 4,126 women in the United States. Participants in 1987 reported higher ideal weights than participants in 2001, an effect particularly pronounced from 1987 to 2001 for younger and obese men (85.5 kg to 94.9 kg) and women (62.2 kg to 70.5 kg). For a given body mass index, higher ideal body weights were associated with greater weight satisfaction but lower intentions to lose weight. Body weight satisfaction was subsequently associated with greater walking/jogging, better diet, and lower lifetime weight loss but with less intention to change physical activity and diet or lose weight (P?

Ardern, Chris I.; Church, Timothy S.; Hebert, James R.; Sui, Xuemei; Blair, Steven N.

2009-01-01

474

Correlates of Ideal Body Size Among Black and White Adolescents  

Microsoft Academic Search

Cultural differences have been found in body image perceptions among Black and White adolescents, however little is known about the factors associated with perceptions of an ideal body size (IBS). This study examined differences in correlates of IBS among 265 Black (116 girls and 62 boys) and White (63 girls and 24 boys) adolescents. IBS for White girls and boys

Nicole Nollen; Harsohena Kaur; Kim Pulvers; Won Choi; Marian Fitzgibbon; Chaoyang Li; Niaman Nazir; Jasjit S. Ahluwalia

2006-01-01

475

Topological Cohen-Macaulay criteria for monomial ideals  

E-print Network

Scattered over the past few years have been several occurrences of simplicial complexes whose topological behavior characterize the Cohen-Macaulay property for quotients of polynomial rings by arbitrary (not necessarily squarefree) monomial ideals. The purpose of this survey is to gather the developments into one location, with self-contained proofs, including direct combinatorial topological connections between them.

Miller, Ezra

2008-01-01

476

Towards An Ideal Slow Cookoff Model For PBXN-109  

Microsoft Academic Search

We present an overview of computational techniques for simulating the thermal cookoff of high explosives using a multi-physics hydrodynamics code, ALE3D. Recent improvements to the code have aided our computational capability in modeling the response of energetic materials