Showing papers on "Non-equilibrium thermodynamics published in 2007"
Book•
14 Aug 2007TL;DR: In this paper, the microscopic connection is used to model the Green-Kubo relations of steady states and the nonlinear response theory of linear irreversible thermodynamics is used for steady states.
Abstract: 1. Introduction 2. Linear irreversible thermodynamics 3. The microscopic connection 4. The Green-Kubo relations 5. Linear response theory 6. Computer simulation algorithms 7. Nonlinear response theory 8. Dynamical stability 9. Nonequilibrium fluctuations 10. Thermodynamics of steady states References Index.
1,586 citations
TL;DR: The relaxation hypothesis is confirmed through an ab initio numerical investigation of the dynamics of hard-core bosons on a one-dimensional lattice, and a natural extension of the Gibbs ensemble to integrable systems results in a theory that is able to predict the mean values of physical observables after relaxation.
Abstract: In this Letter we pose the question of whether a many-body quantum system with a full set of conserved quantities can relax to an equilibrium state, and, if it can, what the properties of such a state are. We confirm the relaxation hypothesis through an ab initio numerical investigation of the dynamics of hard-core bosons on a one-dimensional lattice. Further, a natural extension of the Gibbs ensemble to integrable systems results in a theory that is able to predict the mean values of physical observables after relaxation. Finally, we show that our generalized equilibrium carries more memory of the initial conditions than the usual thermodynamic one. This effect may have many experimental consequences, some of which have already been observed in the recent experiment on the nonequilibrium dynamics of one-dimensional hard-core bosons in a harmonic potential [T. Kinoshita et al., Nature (London) 440, 900 (2006)].
1,390 citations
Book•
01 Jan 2007
TL;DR: Calculating Free Energy Differences Using Perturbation Theory and Specialized Methods for Improving Ergodic Sampling Using Molecular Dynamics and Monte Carlo Simulations.
Abstract: Calculating Free Energy Differences Using Perturbation Theory.- Methods Based on Probability Distributions and Histograms.- Thermodynamic Integration Using Constrained and Unconstrained Dynamics.- Nonequilibrium Methods for Equilibrium Free Energy Calculations.- Understanding and Improving Free Energy Calculations in Molecular Simulations: Error Analysis and Reduction Methods.- Transition Path Sampling and the Calculation of Free Energies.- Specialized Methods for Improving Ergodic Sampling Using Molecular Dynamics and Monte Carlo Simulations.- Potential Distribution Methods and Free Energy Models of Molecular Solutions.- Methods for Examining Phase Equilibria.- Quantum Contributions to Free Energy Changes in Fluids.- Free Energy Calculations: Approximate Methods for Biological Macromolecules.- Applications of Free Energy Calculations to Chemistry and Biology.- Summary and Outlook.
329 citations
14 Mar 2007
289 citations
TL;DR: In this paper, a framework for predicting O2 reduction rate laws based on specific reaction mechanisms was proposed to aid interpretation of existing kinetic data, and generate testable hypotheses for further research, and this framework yields rate laws that are rigorously consistent with thermodynamics, yet allow rates of individual steps to be developed in terms of simple mass action laws.
281 citations
TL;DR: An alternative master equation is derived that is capable of describing a stationary energy current and, at the same time, leads to a completely positive dynamical map that paves the way for efficient numerical investigations of heat transport in larger systems based on Monte Carlo wave function techniques.
Abstract: We investigate heat transport in a spin-1/2 Heisenberg chain, coupled locally to independent thermal baths of different temperature. The analysis is carried out within the framework of the theory of open systems by means of appropriate quantum master equations. The standard microscopic derivation of the weak-coupling Lindblad equation in the secular approximation is considered, and shown to be inadequate for the description of stationary nonequilibrium properties like a nonvanishing energy current. Furthermore, we derive an alternative master equation that is capable of describing a stationary energy current and, at the same time, leads to a completely positive dynamical map. This paves the way for efficient numerical investigations of heat transport in larger systems based on Monte Carlo wave function techniques.
200 citations
TL;DR: In this article, instead of applying a thermal boundary condition to solute transport, the authors rigorously derive the distribution function boundary condition for the total solute concentration, which is achieved first by correcting an expression of the particle distribution function in terms of the corresponding concentration and its gradient and then by deriving and using the relation that the nonequilibrium portion of the distribution functions in opposite directions takes on opposite signs.
Abstract: [1] In this paper, we improve the lattice Boltzmann pore-scale model for multicomponent reactive transport in porous media developed in a previous study. Instead of applying a thermal boundary condition to solute transport, we rigorously derive the distribution function boundary condition for the total solute concentration. This is achieved first by correcting an expression of the particle distribution function in terms of the corresponding concentration and its gradient and then by deriving and using the relation that the nonequilibrium portion of the distribution function in opposite directions takes on opposite signs. We implement the new boundary condition in both the two-dimensional nine-speed (D2Q9) and four-speed (D2Q4) lattices. Simulations of reactive transport in various chemical and geometrical systems using different models are carried out, and results are compared to analytic expressions or two-dimensional FLOTRAN simulations. It is found that with this new boundary condition, the solute mass is strictly conserved by heterogeneous reactions, as was not the case using the thermal boundary condition. It is also found that compared with the D2Q9 model, the D2Q4 model has comparable accuracy and better computational efficiency.
192 citations
TL;DR: In this paper, the relationship between these two sets of results is elucidated, then illustrated with an undergraduate-level solvable model, and the analysis also serves to clarify the physical interpretation of different definitions of work that have been used in the context of thermodynamic systems driven away from equilibrium.
170 citations
Book•
01 Jan 2007
TL;DR: The Third Law of Thermodynamics and the Thermodynamic of Irreversible Processes have been studied extensively in the literature as mentioned in this paper, with a focus on chemical potentials.
Abstract: Temperature.- Energy.- Entropy.- Entropy as S = k ln W.- Chemical Potentials.- Third Law of Thermodynamics.- Radiation Thermodynamics.- Thermodynamics of Irreversible Processes.- Fluctuations.- Relativistic Thermodynamics.- Metabolism.
165 citations
TL;DR: Experimental results are presented showing that the difference of a Brownian particle in a trap moving at constant speed and an electric circuit with an imposed mean current equals the thermodynamic entropy production in units of Boltzmann's constant.
Abstract: The time-reversal symmetry of nonequilibrium fluctuations is experimentally investigated in two out-of-equilibrium systems: namely, a Brownian particle in a trap moving at constant speed and an electric circuit with an imposed mean current. The dynamical randomness of their nonequilibrium fluctuations is characterized in terms of the standard and time-reversed entropies per unit time of dynamical systems theory. We present experimental results showing that their difference equals the thermodynamic entropy production in units of Boltzmann's constant.
152 citations
TL;DR: A theorem is introduced that relates forward and reverse fluxes and free energy for any chemical process operating in a steady state to provide a novel equivalent definition for chemical reaction free energy.
Abstract: Chemical reaction systems operating in nonequilibrium open-system states arise in a great number of contexts, including the study of living organisms, in which chemical reactions, in general, are far from equilibrium. Here we introduce a theorem that relates forward and reverse fluxes and free energy for any chemical process operating in a steady state. This relationship, which is a generalization of equilibrium conditions to the case of a chemical process occurring in a nonequilibrium steady state in dilute solution, provides a novel equivalent definition for chemical reaction free energy. In addition, it is shown that previously unrelated theories introduced by Ussing and Hodgkin and Huxley for transport of ions across membranes, Hill for catalytic cycle fluxes, and Crooks for entropy production in microscopically reversible systems, are united in a common framework based on this relationship.
TL;DR: Three integral fluctuation theorems are derived for these contributions and it is shown that they lead to the following universal inequality: An arbitrary nonequilibrium transformation always produces a change in the total entropy production greater than or equal to the one produced if the transformation is done very slowly (adiabatically).
Abstract: The total entropy production generated by the dynamics of an externally driven systems exchanging energy and matter with multiple reservoirs and described by a master equation is expressed as the sum of three contributions, each corresponding to a distinct mechanism for bringing the system out of equilibrium: Nonequilibrium initial conditions, external driving, and breaking of detailed balance. We derive three integral fluctuation theorems (FTs) for these contributions and show that they lead to the following universal inequality: An arbitrary nonequilibrium transformation always produces a change in the total entropy production greater than or equal to the one produced if the transformation is done very slowly (adiabatically). Previously derived fluctuation theorems can be recovered as special cases. We show how these FTs can be experimentally tested by performing the counting statistics of the electrons crossing a single level quantum dot coupled to two reservoirs with externally varying chemical potentials. The entropy probability distributions are simulated for driving protocols ranging from the adiabatic to the sudden switching limit.
TL;DR: The method is applied to the nonequilibrium rare event problem proposed by Maier and Stein, to nucleation in a 2-dimensional Ising system, and to the flipping of a genetic switch.
Abstract: We present a method for computing stationary distributions for activated processes in equilibrium and nonequilibrium systems using forward flux sampling. In this method, the stationary distributions are obtained directly from the rate constant calculations for the forward and backward reactions; there is no need to perform separate calculations for the stationary distribution and the rate constant. We apply the method to the nonequilibrium rare event problem proposed by Maier and Stein, to nucleation in a 2-dimensional Ising system, and to the flipping of a genetic switch.
TL;DR: This work compares and characterize the behavior of Langevin and dissipative particle dynamics (DPD) thermostats in a broad range of nonequilibrium simulations of polymeric systems and quantitatively analyzes the efficiency and limitations of different Langevine and DPD thermostat implementations.
Abstract: In this work we compare and characterize the behavior of Langevin and dissipative particle dynamics (DPD) thermostats in a broad range of nonequilibrium simulations of polymeric systems. Polymer brushes in relative sliding motion, polymeric liquids in Poiseuille and Couette flows, and brush-melt interfaces are used as model systems to analyze the efficiency and limitations of different Langevin and DPD thermostat implementations. Widely used coarse-grained bead-spring models under good and poor solvent conditions are employed to assess the effects of the thermostats. We considered equilibrium, transient, and steady state examples for testing the ability of the thermostats to maintain constant temperature and to reproduce the underlying physical phenomena in nonequilibrium situations. The common practice of switching off the Langevin thermostat in the flow direction is also critically revisited. The efficiency of different weight functions for the DPD thermostat is quantitatively analyzed as a function of the solvent quality and the nonequilibrium situation.
TL;DR: In this paper, the authors provide an introduction to some stochastic models of lattice gases out of equilibrium and a discussion of results of various kinds obtained in recent years, based on an approach developed by the authors based on the study of dynamical large fluctuations in stationary states of open systems.
Abstract: This paper provides an introduction to some stochastic models of lattice gases out of equilibrium and a discussion of results of various kinds obtained in recent years. Although these models are different in their microscopic features, a unified picture is emerging at the macroscopic level, applicable, in our view, to real phenomena where diffusion is the dominating physical mechanism. We rely mainly on an approach developed by the authors based on the study of dynamical large fluctuations in stationary states of open systems. The outcome of this approach is a theory connecting the non equilibrium thermodynamics to the transport coefficients via a variational principle. This leads ultimately to a functional derivative equation of Hamilton-Jacobi type for the non equilibrium free energy in which local thermodynamic variables are the independent arguments. In the first part of the paper we give a detailed introduction to the microscopic dynamics considered, while the second part, devoted to the macroscopic properties, illustrates many consequences of the Hamilton-Jacobi equation. In both parts several novelties are included.
14 Mar 2007
TL;DR: In this paper, the Curie symmetry principle and the Onsager relation are used to describe the normal components of the velocity field at the dividing surface of a liquid-vapor interface.
Abstract: I . Introduction A . Historical Remarks B . On the Mathematical Description of Interfaces I1 . Conservation Laws: A . Introduction B . Conservation of Mass C . The General Form of Interfacial Balance Equations D . Conservation of Momentum E . Conservation of Energy 111 . Entropy Balance A . The Second L.aw of Thermodynamics B . The Entropy .Production IV . The Phenomenological Equations A . Introduction B . The Curie Symmetry Principle C . The Onsager Relations D . Symmetric Traceless Tensorial Force-Flux Pairs E . Vectorial Force-Flux Pairs F . Scalar Force-Flux Pairs G . The Normal Components of the Velocity Field at the Dividing Surface ... H . The Liquid-Vapor Interface V . Equilibrium Fluctuations of a Liquid-Vapor Interface A . Introduction B . Fluctuations in the Location of the Dividing Surface C . The Equilibrium Distribution D . The Height-Height Correlation Function E . The Average Density Profile F . The Density-Density Correlation Function G . Spectral Representation of the Density-Density Correlation Function in
TL;DR: In this paper, a three-ring catenane-based motor based on a 3-ring C-catenane is considered, where the modulation is carried out slowly enough that the state probabilities obey a Boltzmann equilibrium distribution at every instant.
Abstract: Operation of a molecular machine is often thought of as a “far from equilibrium” process in which energy released by some high free energy fuel molecule or by light is used to drive a nonequilibrium “power stroke” to do work on the environment. Here we discuss how a molecular machine can be operated arbitrarily close to chemical equilibrium and still perform significant work at an appreciable rate: micrometer per second velocities against piconewton loads. As a specific example, we focus on a motor based on a three-ring catenane similar to that discussed by Leigh [Leigh DA, Wong JKY, Dehez F, Zerbetto F (2003) Nature 424:174–179]. The machine moves through its working cycle under the influence of external modulation of the energies of the states, where the modulation is carried out slowly enough that the state probabilities obey a Boltzmann equilibrium distribution at every instant. The mechanism can be understood in terms of the geometric phase [Berry MV (1990) Phys Today 43(12):34–40] in which the system moves adiabatically around a closed loop in parameter space, completing, on average, nearly one-half mechanical cycle each time it does so. Because the system is very close to equilibrium at every instant, the efficiency can approach 100%.
TL;DR: It is found that nonlinearity suppresses thermal transport even at moderately high temperatures.
Abstract: We present a detailed treatment of the nonequilibrium Green's function method for thermal transport due to atomic vibrations in nanostructures. Some of the key equations, such as self-energy and conductance with nonlinear effect, are derived. A self-consistent mean-field theory is proposed. Computational procedures are discussed. The method is applied to a number of systems including one-dimensional chains, a benzene ring junction, and carbon nanotubes. Mean-field calculations of the Fermi-Pasta-Ulam model are compared with classical molecular dynamics simulations using a generalized Langevin heat bath. We find that nonlinearity suppresses thermal transport even at moderately high temperatures.
TL;DR: It is shown that thermal wave relaxation to equilibrium may be characterized by the existence of a genuine condensation process, whose thermodynamic properties are analogous to those of Bose-Einstein condensation, despite the fact that the considered optical wave is completely classical.
Abstract: This concise review is aimed at providing an introduction to the kinetic theory of partially coherent optical waves propagating in nonlinear media. The subject of incoherent nonlinear optics received a renewed interest since the first experimental demonstration of incoherent solitons in slowly responding photorefractive crystals. Several theories have been successfully developed to provide a detailed description of the novel dynamical features inherent to partially coherent nonlinear optical waves. However, such theories leave unanswered the following important question: Which is the long term (spatiotemporal) evolution of a partially incoherent optical field propagating in a nonlinear medium? In complete analogy with kinetic gas theory, one may expect that the incoherent field may evolve, owing to nonlinearity, towards a thermodynamic equilibrium state. Weak-turbulence theory is shown to describe the essential properties of this irreversible process of thermal wave relaxation to equilibrium. Precisely, the theory describes an irreversible evolution of the spectrum of the field towards a thermodynamic equilibrium state. The irreversible behavior is expressed through the H-theorem of entropy growth, whose origin is analogous to the celebrated Boltzmann’s H-theorem of kinetic gas theory. It is shown that thermal wave relaxation to equilibrium may be characterized by the existence of a genuine condensation process, whose thermodynamic properties are analogous to those of Bose-Einstein condensation, despite the fact that the considered optical wave is completely classical. In spite of the formal reversibility of optical wave propagation, the condensation process occurs by means of an irreversible evolution of the field towards a homogeneous plane-wave (condensate) with small-scale fluctuations superimposed (uncondensed particles), which store the information necessary for the reversible propagation. As a remarkable result, an increase of entropy (“disorder”) in the optical field requires the generation of a coherent structure (plane-wave). We show that, beyond the standard thermodynamic limit, wave condensation also occurs in two spatial dimensions. The numerical simulations are in quantitative agreement with the kinetic wave theory, without any adjustable parameter.
TL;DR: A finite volume discretization of the compressible isothermal fluctuating hydrodynamic equations over a regular grid in the Eulerian reference system is derived and is shown to be thermodynamically consistent and correctly reproduces linear hydrodynamics including relaxation of sound and shear modes.
Abstract: A good representation of mesoscopic fluids is required to combine with molecular simulations at larger length and time scales [De Fabritiis et al., Phys. Rev. Lett. 97, 134501 (2006)]. However, accurate computational models of the hydrodynamics of nanoscale molecular assemblies are lacking, at least in part because of the stochastic character of the underlying fluctuating hydrodynamic equations. Here we derive a finite volume discretization of the compressible isothermal fluctuating hydrodynamic equations over a regular grid in the Eulerian reference system. We apply it to fluids such as argon at arbitrary densities and water under ambient conditions. To that end, molecular dynamics simulations are used to derive the required fluid properties. The equilibrium state of the model is shown to be thermodynamically consistent and correctly reproduces linear hydrodynamics including relaxation of sound and shear modes. We also consider nonequilibrium states involving diffusion and convection in cavities with no-slip boundary conditions.
TL;DR: An analysis of the experimental data of kinesin using the framework leads to interesting predictions that may serve as a guide for future experiments.
Abstract: We investigate theoretically the violations of Einstein and Onsager relations and the thermodynamic efficiency for a single processive motor operating far from equilibrium using an extension of the two-state model introduced by Kafri et al. [Biophys. J. 86, 3373 (2004)]. With the aid of the Fluctuation Theorem, we analyze the general features of these violations and this efficiency and link them to mechanochemical couplings of motors. In particular, an analysis of the experimental data of kinesin using our framework leads to interesting predictions that may serve as a guide for future experiments.
TL;DR: A thermodynamiclike formalism is developed for superstatistical systems based on conditional entropies that takes into account large-scale variations of intensive variables of systems in nonequilibrium stationary states.
Abstract: A thermodynamiclike formalism is developed for superstatistical systems based on conditional entropies. This theory takes into account large-scale variations of intensive variables of systems in nonequilibrium stationary states. Ordinary thermodynamics is recovered as a special case of the present theory, and corrections to it can systematically be evaluated. A generalization of Einstein's relation for fluctuations is presented using a maximum entropy condition.
TL;DR: In this paper, the probability functional for a path is expressed in terms of a Lagrangian function from which an entropy production rate and dissipation functions are introduced, and nonequilibrium thermodynamic relations like the energy conservation law and the second law of thermodynamics are derived.
Abstract: A generalization of the Onsager-Machlup theory from equilibrium to nonequilibrium steady states and its connection with recent fluctuation theorems are discussed for a dragged particle restricted by a harmonic potential in a heat reservoir. Using a functional integral approach, the probability functional for a path is expressed in terms of a Lagrangian function from which an entropy production rate and dissipation functions are introduced, and nonequilibrium thermodynamic relations like the energy conservation law and the second law of thermodynamics are derived. Using this Lagrangian function we establish two nonequilibrium detailed balance relations, which not only lead to a fluctuation theorem for work but also to one related to energy loss by friction. In addition, we carried out the functional integral for heat explicitly, leading to the extended fluctuation theorem for heat. We also present a simple argument for this extended fluctuation theorem in the long time limit.
TL;DR: An ultralocal limit of the microscopic single particle barrier hopping theory of glassy dynamics is proposed which allows explicit analytic expressions for the characteristic length scales, energy scales, and nonequilibrium free energy to be derived.
Abstract: An ultralocal limit of the microscopic single particle barrier hopping theory of glassy dynamics is proposed which allows explicit analytic expressions for the characteristic length scales, energy scales, and nonequilibrium free energy to be derived. All properties are shown to be controlled by a single coupling constant determined by the fluid density and contact value of the radial distribution function. This parameter quantifies an effective mean square force exerted on a tagged particle due to collisions with its surroundings. The analysis suggests a conceptual basis for previous surprising findings of multiple inter-relationships between characteristics of the transient localized state, the early stages of cage escape, non-Gaussian or dynamic heterogeneity effects, and the barrier hopping process that defines the alpha relaxation event. The underlying physical picture is also relevant to fluids of nonspherical molecules and sticky colloidal suspensions. The possibility of a unified view of liquid dynamics is suggested spanning the range from dense gases to the zero mobility jammed state.
TL;DR: In this article, the steady state fluctuation relation for the dissipation function of a driven nonequilibrium system whose transients relax, producing a unique none-ilibrium steady state, is shown to be a consequence of time reversibility and a form of decay of correlations in dissipation.
Abstract: We give a proof of transient fluctuation relations for the entropy production (dissipation function) in nonequilibrium systems, which is valid for most time reversible dynamics. We then consider the conditions under which a transient fluctuation relation yields a steady state fluctuation relation for driven nonequilibrium systems whose transients relax, producing a unique nonequilibrium steady state. Although the necessary and sufficient conditions for the production of a unique nonequilibrium steady state are unknown, if such a steady state exists, the generation of the steady state fluctuation relation from the transient relation is shown to be very general. It is essentially a consequence of time reversibility and of a form of decay of correlations in the dissipation, which is needed also for, e.g., the existence of transport coefficients. Because of this generality the resulting steady state fluctuation relation has the same degree of robustness as do equilibrium thermodynamic equalities. The steady state fluctuation relation for the dissipation stands in contrast with the one for the phase space compression factor, whose convergence is problematic, for systems close to equilibrium. We examine some model dynamics that have been considered previously, and show how they are described in the context of this work.
TL;DR: The imaginary-time formulation of the equilibrium quantum many-body theory is extended to steady-state nonequilibrium with an application to strongly correlated transport in the Kondo regime using the quantum Monte Carlo method.
Abstract: We extend the imaginary-time formulation of the equilibrium quantum many-body theory to steady-state nonequilibrium with an application to strongly correlated transport. By introducing the Matsubara voltage, we maintain the finite chemical potential shifts in the Fermi-Dirac function, in agreement with the Keldysh formulation. The formulation is applied to strongly correlated transport in the Kondo regime using the quantum Monte Carlo method.
TL;DR: A systematic description of the kinetic LBM, including the lattice Boltzmann equation, the diffuse-scattering boundary condition for gas-surface interactions, and definition of the relaxation time, is provided.
Abstract: It is well known that the Navier-Stokes equations cannot adequately describe gas flows in the transition and free-molecular regimes. In these regimes, the Boltzmann equation (BE) of kinetic theory is invoked to govern the flows. However, this equation cannot be solved easily, either by analytical techniques or by numerical methods. Hence, in order to efficiently maneuver around this equation for modeling microscale gas flows, a kinetic lattice Boltzmann method (LBM) has been introduced in recent years. This method is regarded as a numerical approach for solving the BE in discrete velocity space with Gauss-Hermite quadrature. In this paper, a systematic description of the kinetic LBM, including the lattice Boltzmann equation, the diffuse-scattering boundary condition for gas-surface interactions, and definition of the relaxation time, is provided. To capture the nonlinear effects due to the high-order moments and wall boundaries, an effective relaxation time and a modified regularization procedure of the nonequilibrium part of the distribution function are further presented based on previous work [Guo et al., J. Appl. Phys. 99, 074903 (2006); Shan et al., J. Fluid Mech. 550, 413 (2006)]. The capability of the kinetic LBM of simulating microscale gas flows is illustrated based on the numerical investigations of micro Couette and force-driven Poiseuille flows.
TL;DR: A general argument leading from the formula for currents through an open noninteracting mesoscopic system given by the theory of nonequilibrium steady states to the Landauer-Buttiker formula is pointed out in this article.
Abstract: A general argument leading from the formula for currents through an open noninteracting mesoscopic system given by the theory of nonequilibrium steady states to the Landauer-Buttiker formula is pointed out. Time reversal symmetry is not assumed. As a consequence it is shown that, as far as the system has a nontrivial scattering theory and the reservoirs have different temperatures and/or chemical potentials, the entropy production is strictly positive.
TL;DR: It is shown that neglecting the inverse triple interactions prevents reaching thermal equilibrium in a homogeneous isotropic pair plasma and the results obtained in the theoretical physics domain also find application in astrophysics and cosmology.
Abstract: Starting from a nonequilibrium configuration we analyze the role of the direct and the inverse binary and triple interactions in reaching thermal equilibrium in a homogeneous isotropic pair plasma. We focus on energies in the range 0.1-10 MeV. We numerically integrate the relativistic Boltzmann equation with the exact QED collisional integrals taking into account all binary and triple interactions. We show that first, when a detailed balance is reached for all binary interactions on a time scale t{sub k} < or approx. 10{sup -14} sec, photons and electron-positron pairs establish kinetic equilibrium. Subsequently, when triple interactions satisfy the detailed balance on a time scale t{sub eq} < or approx. 10{sup -12} sec, the plasma reaches thermal equilibrium. It is shown that neglecting the inverse triple interactions prevents reaching thermal equilibrium. Our results obtained in the theoretical physics domain also find application in astrophysics and cosmology.
TL;DR: A simple transport model driven out of equilibrium by reservoirs at the boundaries is studied, corresponding to the hydrodynamic limit of the symmetric simple exclusion process and it is shown that a nonlocal transformation of densities and currents maps the large deviations of the model into those of an open, isolated chain satisfying detailed balance.
Abstract: We study a simple transport model driven out of equilibrium by reservoirs at the boundaries, corresponding to the hydrodynamic limit of the symmetric simple exclusion process. We show that a nonlocal transformation of densities and currents maps the large deviations of the model into those of an open, isolated chain satisfying detailed balance, where rare fluctuations are the time reversals of relaxations. We argue that the existence of such a mapping is the immediate reason why it is possible for this model to obtain an explicit solution for the large-deviation function of densities through elementary changes of variables. This approach can be generalized to the other models previously treated with the macroscopic fluctuation theory.