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Modeling the dynamics of a tracer particle in an elastic active gel ; Fodor, Etienne ; et al in Physical Review. E. (2015), 92(1), The internal dynamics of active gels both in artificial (in vitro) model systems and inside the cytoskeleton of living cells has been extensively studied with experiments of recent years. These dynamics ... [more ▼] The internal dynamics of active gels both in artificial (in vitro) model systems and inside the cytoskeleton of living cells has been extensively studied with experiments of recent years. These dynamics are probed using tracer particles embedded in the network of biopolymers together with molecular motors, and distinct nonthermal behavior is observed. We present a theoretical model of the dynamics of a trapped active particle, which allows us to quantify the deviations from equilibrium behavior, using both analytic and numerical calculations. We map the different regimes of dynamics in this system and highlight the different manifestations of activity: breakdown of the virial theorem and equipartition, different elasticity-dependent ``effective temperatures,'' and distinct non-Gaussian distributions. Our results shed light on puzzling observations in active gel experiments and provide physical interpretation of existing observations, as well as predictions for future studies. [less ▲] Detailed reference viewed: 68 (1 UL)Fluctuating currents in stochastic thermodynamics. I. Gauge invariance of asymptotic statistics Wachtel, Artur ; ; in Physical Review. E. (2015), 92(4), 042132 Stochastic thermodynamics uses Markovian jump processes to model random transitions between observable mesoscopic states. Physical currents are obtained from antisymmetric jump observables defined on the ... [more ▼] Stochastic thermodynamics uses Markovian jump processes to model random transitions between observable mesoscopic states. Physical currents are obtained from antisymmetric jump observables defined on the edges of the graph representing the network of states. The asymptotic statistics of such currents are characterized by scaled cumulants. In the present work, we use the algebraic and topological structure of Markovian models to prove a gauge invariance of the scaled cumulant-generating function. Exploiting this invariance yields an efficient algorithm for practical calculations of asymptotic averages and correlation integrals. We discuss how our approach generalizes the Schnakenberg decomposition of the average entropy-production rate, and how it unifies previous work. The application of our results to concrete models is presented in an accompanying publication. [less ▲] Detailed reference viewed: 110 (3 UL)Universal theory of efficiency fluctuations ; ; et al in Physical Review. E. (2014), 90(5), Detailed reference viewed: 180 (8 UL)Energetics of active fluctuations in living cells Fodor, Etienne ; ; et al in Physical Review. E. (2014), 90(4), The nonequilibrium activity taking place in a living cell can be monitored with a tracer embedded in the medium. While microrheology experiments based on optical manipulation of such probes have become ... [more ▼] The nonequilibrium activity taking place in a living cell can be monitored with a tracer embedded in the medium. While microrheology experiments based on optical manipulation of such probes have become increasingly standard, we put forward a number of experiments with alternative protocols that, we claim, will provide insight into the energetics of active fluctuations. These are based on either performing thermodynamiclike cycles in control-parameter space or determining response to external perturbations of the confining trap beyond simple translation. We illustrate our proposals on an active itinerant Brownian oscillator modeling the dynamics of a probe embedded in a living medium. [less ▲] Detailed reference viewed: 73 (2 UL)Nonconvexity of the relative entropy for Markov dynamics: A Fisher information approach Polettini, Matteo ; Esposito, Massimiliano in Physical Review. E. (2013), 88 We show via counterexamples that relative entropy between the solution of a Markovian master equation and the steady state is not a convex function of time. We thus disprove the hypotheses that a general ... [more ▼] We show via counterexamples that relative entropy between the solution of a Markovian master equation and the steady state is not a convex function of time. We thus disprove the hypotheses that a general evolution principle of thermodynamics based on the decrease of the nonadiabatic entropy production could hold. However, we argue that a large separation of typical decay times is necessary for nonconvex solutions to occur, making concave transients extremely short lived with respect to the main relaxation modes. We describe a general method based on the Fisher information matrix to discriminate between generators that admit nonconvex solutions and those that do not. While initial conditions leading to concave transients are shown to be extremely fine-tuned, by our method we are able to select nonconvex initial conditions that are arbitrarily close to the steady state. Convexity does occur when the system is close to satisfying detailed balance or, more generally, when certain normality conditions of the decay modes are satisfied. Our results circumscribe the range of validity of a conjecture by Maes et al. [ Phys. Rev. Lett. 107 010601 (2011)] regarding monotonicity of the large deviation rate functional for the occupation probability, showing that while the conjecture might hold in the long-time limit, the conditions for Lyapunov's second criterion for stability are not met. [less ▲] Detailed reference viewed: 219 (7 UL)Stochastically driven single-level quantum dot: A nanoscale finite-time thermodynamic machine and its various operational modes Esposito, Massimiliano ; ; et al in Physical Review. E. (2012), 85(3), We describe a single-level quantum dot in contact with two leads as a nanoscale finite-time thermodynamic machine. The dot is driven by an external stochastic force that switches its energy between two ... [more ▼] We describe a single-level quantum dot in contact with two leads as a nanoscale finite-time thermodynamic machine. The dot is driven by an external stochastic force that switches its energy between two values. In the isothermal regime, it can operate as a rechargeable battery by generating an electric current against the applied bias in response to the stochastic driving and then redelivering work in the reverse cycle. This behavior is reminiscent of the Parrondo paradox. If there is a thermal gradient the device can function as a work-generating thermal engine or as a refrigerator that extracts heat from the cold reservoir via the work input of the stochastic driving. The efficiency of the machine at maximum power output is investigated for each mode of operation, and universal features are identified. [less ▲] Detailed reference viewed: 139 (4 UL)Stochastic thermodynamics under coarse graining Esposito, Massimiliano in Physical Review. E. (2012), 85(4), A general formulation of stochastic thermodynamics is presented for open systems exchanging energy and particles with multiple reservoirs. By introducing a partition in terms of “mesostates” (e.g., sets ... [more ▼] A general formulation of stochastic thermodynamics is presented for open systems exchanging energy and particles with multiple reservoirs. By introducing a partition in terms of “mesostates” (e.g., sets of “microstates”), the consequence on the thermodynamic description of the system is studied in detail. When microstates within mesostates rapidly thermalize, the entire structure of the microscopic theory is recovered at the mesostate level. This is not the case when these microstates remain out of equilibrium, leading to additional contributions to the entropy balance. Some of our results are illustrated for a model of two coupled quantum dots. [less ▲] Detailed reference viewed: 187 (9 UL)Thermodynamics of a stochastic twin elevator ; ; Esposito, Massimiliano et al in Physical Review. E. (2011), 84(5), We study the nonequilibrium thermodynamics of a single particle with two available energy levels, in contact with a classical (Maxwell-Boltzmann) or quantum (Bose-Einstein) heat bath. The particle can ... [more ▼] We study the nonequilibrium thermodynamics of a single particle with two available energy levels, in contact with a classical (Maxwell-Boltzmann) or quantum (Bose-Einstein) heat bath. The particle can undergo transitions between the levels via thermal activation or deactivation. The energy levels are alternately raised at a given rate regardless of occupation by the particle, maintaining a fixed energy gap equal to ε between them. We explicitly calculate the work, heat, and entropy production rates. The efficiency in both the classical and the quantum case goes to a limit between 100 and 50% that depends on the relative rates of particle transitions and level elevation. In the classical problem we explicitly find the large deviation functions for heat, work, and internal energy. [less ▲] Detailed reference viewed: 751 (1 UL)Three faces of the second law. I. Master equation formulation Esposito, Massimiliano ; in Physical Review. E. (2010), 82(1), We propose a formulation of stochastic thermodynamics for systems subjected to nonequilibrium constraints i.e. broken detailed balance at steady state and furthermore driven by external time-dependent ... [more ▼] We propose a formulation of stochastic thermodynamics for systems subjected to nonequilibrium constraints i.e. broken detailed balance at steady state and furthermore driven by external time-dependent forces. A splitting of the second law occurs in this description leading to three second-law-like relations. The general results are illustrated on specific solvable models. The present paper uses a master equation based approach. [less ▲] Detailed reference viewed: 95 (1 UL)Quantum-dot Carnot engine at maximum power Esposito, Massimiliano ; ; et al in Physical Review. E. (2010), 81(4), We evaluate the efficiency at maximum power of a quantum-dot Carnot heat engine. The universal values of the coefficients at the linear and quadratic order in the temperature gradient are reproduced ... [more ▼] We evaluate the efficiency at maximum power of a quantum-dot Carnot heat engine. The universal values of the coefficients at the linear and quadratic order in the temperature gradient are reproduced. Curzon-Ahlborn efficiency is recovered in the limit of weak dissipation. [less ▲] Detailed reference viewed: 109 (1 UL)Three faces of the second law. II. Fokker-Planck formulation ; Esposito, Massimiliano in Physical Review. E. (2010), 82(1), The total entropy production is the sum of two contributions, the so-called adiabatic and nonadiabatic entropy productions, each of which is non-negative. We derive their explicit expressions for ... [more ▼] The total entropy production is the sum of two contributions, the so-called adiabatic and nonadiabatic entropy productions, each of which is non-negative. We derive their explicit expressions for continuous Markovian processes, discuss their properties, and illustrate their behavior on two exactly solvable models. [less ▲] Detailed reference viewed: 94 (1 UL)Pulse propagation in tapered granular chains: An analytic study ; ; Esposito, Massimiliano et al in Physical Review. E. (2009), 80(3), Detailed reference viewed: 87 (1 UL)Pulse propagation in decorated granular chains: An analytical approach ; ; et al in Physical Review. E. (2009), 80(5), Detailed reference viewed: 81 (1 UL)Continuous-time random walk for open systems: Fluctuation theorems and counting statistics Esposito, Massimiliano ; in Physical Review. E. (2008), 77(5), Detailed reference viewed: 54 (1 UL)Entropy fluctuation theorems in driven open systems: Application to electron counting statistics Esposito, Massimiliano ; ; in Physical Review. E. (2007), 76(3), Detailed reference viewed: 39 (1 UL)Quantum master equation for the microcanonical ensemble Esposito, Massimiliano ; in Physical Review. E. (2007), 76(4), Detailed reference viewed: 44 (1 UL)Fluctuation theorems for quantum master equations Esposito, Massimiliano ; in Physical Review. E. (2006), 73(4), Detailed reference viewed: 34 (1 UL)Pseudopath semiclassical approximation to transport through open quantum billiards: Dyson equation for diffractive scattering ; ; et al in Physical Review. E. (2005), 72(3), We present a semiclassical theory for transport through open billiards of arbitrary convex shape that includes diffractively scattered paths at the lead openings. Starting from a Dyson equation for the ... [more ▼] We present a semiclassical theory for transport through open billiards of arbitrary convex shape that includes diffractively scattered paths at the lead openings. Starting from a Dyson equation for the semiclassical Green's function we develop a diagrammatic expansion that allows a systematic summation over classical and pseudopaths, the latter consisting of classical paths joined by diffractive scatterings ("kinks"). This renders the inclusion of an exponentially proliferating number of pseudopath combinations numerically tractable for both regular and chaotic billiards. For a circular billiard and the Bunimovich stadium the path sum leads to a good agreement with the quantum path length power spectrum up to long path length. Furthermore, we find excellent numerical agreement with experimental studies of quantum scattering in microwave billiards where pseudopaths provide a significant contribution. [less ▲] Detailed reference viewed: 116 (1 UL)Quantum master equation for a system influencing its environment Esposito, Massimiliano ; in Physical Review. E. (2003), 68(6), Detailed reference viewed: 40 (1 UL)Spin relaxation in a complex environment Esposito, Massimiliano ; in Physical Review. E. (2003), 68(6), Detailed reference viewed: 111 (1 UL) |
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