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The unlikely Carnot efficiency Verley, Gatien ; Esposito, Massimiliano ; et al in Nature Communications (2014) The efficiency of an heat engine is traditionally defined as the ratio of its average output work over its average input heat. Its highest possible value was discovered by Carnot in 1824 and is a ... [more ▼] The efficiency of an heat engine is traditionally defined as the ratio of its average output work over its average input heat. Its highest possible value was discovered by Carnot in 1824 and is a cornerstone concept in thermodynamics. It led to the discovery of the second law and to the definition of the Kelvin temperature scale. Small-scale engines operate in the presence of highly fluctuating input and output energy fluxes. They are therefore much better characterized by fluctuating efficiencies. In this study, using the fluctuation theorem, we identify universal features of efficiency fluctuations. While the standard thermodynamic efficiency is, as expected, the most likely value, we find that the Carnot efficiency is, surprisingly, the least likely in the long time limit. Furthermore, the probability distribution for the efficiency assumes a universal scaling form when operating close-to-equilibrium. We illustrate our results analytically and numerically on two model systems. [less ▲] Detailed reference viewed: 341 (125 UL)Irreversible thermodynamics of open chemical networks. I. Emergent cycles and broken conservation laws Polettini, Matteo ; Esposito, Massimiliano in Journal of Chemical Physics (2014), 141 chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks “in a box”, whose thermodynamics is ... [more ▼] chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks “in a box”, whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated with nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation a + b = sY between the number of fundamental affinities a, that of broken conservation laws b and the number of chemostats sY. We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg’s theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction, and of thermodynamic constraints for network reconstruction. [less ▲] Detailed reference viewed: 260 (14 UL)Exact fluctuation theorem without ensemble quantities Bulnes Cuetara, Gregory ; Esposito, Massimiliano ; in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2014), 1402 Evaluating the entropy production (EP) along a stochastic trajectory requires the knowledge of the system probability distribution, an ensemble quantity notoriously difficult to measure. In this letter ... [more ▼] Evaluating the entropy production (EP) along a stochastic trajectory requires the knowledge of the system probability distribution, an ensemble quantity notoriously difficult to measure. In this letter, we show that the EP of nonautonomous systems in contact with multiple reservoirs can be expressed solely in terms of physical quantities measurable at the single trajectory level with a suitable preparation of the initial condition. As a result, we identify universal energy and particle fluctuation relations valid for any measurement time. We apply our findings to an electronic junction model which may be used to verify our prediction experimentally. [less ▲] Detailed reference viewed: 157 (13 UL)Fluctuation theorem and efficiency fluctuations Esposito, Massimiliano Scientific Conference (2014, May 13) Detailed reference viewed: 54 (1 UL)Nonequilibrium Thermodynamics of Chemical Networks Esposito, Massimiliano Scientific Conference (2014, April 22) Detailed reference viewed: 58 (0 UL)Mutual entropy production in bipartite systems Diana, Giovanni ; Esposito, Massimiliano in Journal of Statistical Mechanics : Theory and Experiment (2014) It was recently shown by Barato et al (2013 Phys. Rev. E 87 042104) that the mutual information at the trajectory level of a bipartite Markovian system is not bounded by the entropy production. In the ... [more ▼] It was recently shown by Barato et al (2013 Phys. Rev. E 87 042104) that the mutual information at the trajectory level of a bipartite Markovian system is not bounded by the entropy production. In the same way as Gaspard showed (2004 J. Stat. Phys. 117 599) that the entropy production is not directly related to the Shannon entropy at the trajectory level but is in fact equal to its difference from the so-called time-reversed Shannon entropy, we show in this paper that the difference between the mutual information and its time-reversed form is equal to the mutual entropy production (MEP), i.e. the difference between the full entropy production and that of the two marginal processes. Evaluation of the MEP is in general a difficult task due to non-Markovian effects. For bipartite systems, we provide closed expressions in various limiting regimes which we verify by numerical simulations. [less ▲] Detailed reference viewed: 109 (6 UL)None-quilibrium Thermodynamics of Open Quantum Systems Esposito, Massimiliano Scientific Conference (2014, March 31) Detailed reference viewed: 74 (1 UL)Thermodynamics of quantum-jump-conditioned feedback control ; ; et al in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013), 88(062107), We consider open quantum systems weakly coupled to thermal reservoirs and subjected to quantum feedback operations triggered with or without delay by monitored quantum jumps. We establish a thermodynamic ... [more ▼] We consider open quantum systems weakly coupled to thermal reservoirs and subjected to quantum feedback operations triggered with or without delay by monitored quantum jumps. We establish a thermodynamic description of such systems and analyze how the first and second law of thermodynamics are modified by the feedback. We apply our formalism to study the efficiency of a qubit subjected to a quantum feedback control and operating as a heat pump between two reservoirs. We also demonstrate that quantum feedbacks can be used to stabilize coherences in nonequilibrium stationary states which in some cases may even become pure quantum states. [less ▲] Detailed reference viewed: 171 (4 UL)Nonequilibrium thermodynamics of a double quantum dot coupled to a quantum point contact Esposito, Massimiliano Scientific Conference (2013, November 25) Detailed reference viewed: 575 (176 UL)Effective fluctuation theorems for electron transport in a double quantum dot coupled to a quantum point contact Bulnes Cuetara, Gregroy ; Esposito, Massimiliano ; et al in Physical Review. B : Condensed Matter (2013), 88(115134), A theoretical study is reported of electron transport at finite temperature in a double quantum dot (DQD) capacitively coupled to a quantum point contact (QPC) for the measurement of the DQD charge state ... [more ▼] A theoretical study is reported of electron transport at finite temperature in a double quantum dot (DQD) capacitively coupled to a quantum point contact (QPC) for the measurement of the DQD charge state. Starting from a Hamiltonian model, a master equation is obtained for the stochastic process taking place in the DQD while the QPC is at or away from equilibrium, allowing us to study the measurement back-action of the QPC onto the DQD. The QPC is treated nonperturbatively in our analysis. Effective fluctuation theorems are established for the full counting statistics of the DQD current under different limiting conditions. These fluctuation theorems hold with respect to an effective affinity characterizing the nonequilibrium environment of the DQD and differing from the applied voltage if the QPC is out of equilibrium. The effective affinity may even change its sign if the Coulomb drag of the QPC reverses the DQD current. The thermodynamic implications of the effective fluctuation theorems are discussed. [less ▲] Detailed reference viewed: 146 (5 UL)Sochastic thermodynamics : Engines and demons Esposito, Massimiliano Scientific Conference (2013, July 23) Detailed reference viewed: 90 (3 UL)Thermodynamic cost of sensing in autonomous systems Esposito, Massimiliano Scientific Conference (2013, July 19) Detailed reference viewed: 45 (1 UL)Nonconvexity of the relative entropy for Markov dynamics: A Fisher information approach Polettini, Matteo ; Esposito, Massimiliano in Physics 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: 160 (5 UL)On the thermodynamic cost of sensing in autonomous systems Esposito, Massimiliano Scientific Conference (2013, July) Detailed reference viewed: 49 (2 UL)Entropy-generated power and its efficiency ; ; Esposito, Massimiliano in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013), 88(042105), We propose a simple model for a motor that generates mechanical motion by exploiting an entropic force arising from the topology of the underlying phase space. We show that the generation of mechanical ... [more ▼] We propose a simple model for a motor that generates mechanical motion by exploiting an entropic force arising from the topology of the underlying phase space. We show that the generation of mechanical forces in our system is surprisingly robust to local changes in kinetic and topological parameters. Furthermore, we find that the efficiency at maximum power may show discontinuities. [less ▲] Detailed reference viewed: 117 (5 UL)Entropy production in quantum Brownian motion ; Esposito, Massimiliano ; in Journal of Statistical Mechanics : Theory and Experiment (2013), P04005 We investigate how to coherently define entropy production for a process of transient relaxation in the quantum Brownian motion model for the harmonic potential. We compare a form, referred to as ‘poised’ ... [more ▼] We investigate how to coherently define entropy production for a process of transient relaxation in the quantum Brownian motion model for the harmonic potential. We compare a form, referred to as ‘poised’ (P), which after non-Markovian transients corresponds to a definition of heat as the change in the system Hamiltonian of mean force, with a recent proposal by Esposito et al (ELB) based on a definition of heat as the energy change in the bath. Both expressions yield a positive-definite entropy production and they coincide for vanishing coupling strength, but their difference is proved to be always positive (after non-Markovian transients disappear) and to grow as the coupling strength increases. In the classical ver-damped limit the ‘poised’ entropy production converges to the entropy production used in stochastic thermodynamics. We also investigate the effects of the system size, and of the ensuing Poincar´e recurrences, and how the classical limit is approached. We close by discussing the strongcoupling limit, in which the ideal canonical equilibrium of the bath is violated. [less ▲] Detailed reference viewed: 101 (5 UL)Single-electron transistor strongly coupled to vibrations: counting statistics and fluctuation theorem ; ; et al in New Journal of Physics (2013), 033032 Using a simple quantum master equation approach, we calculate the full counting statistics of a single-electron transistor strongly coupled to vibrations. The full counting statistics contains both the ... [more ▼] Using a simple quantum master equation approach, we calculate the full counting statistics of a single-electron transistor strongly coupled to vibrations. The full counting statistics contains both the statistics of integrated particle and energy currents associated with the transferred electrons and phonons. A universal as well as an effective fluctuation theorem are derived for the general case where the various reservoir temperatures and chemical potentials are different. The first relates to the entropy production generated in the junction, while the second reveals internal information of the system. The model recovers the Franck–Condon blockade, and potential applications to noninvasive molecular spectroscopy are discussed. [less ▲] Detailed reference viewed: 86 (5 UL)Stochastic Thermodynamics and Information Processing Esposito, Massimiliano Scientific Conference (2013, March 11) I will start by presenting different ways in which one can use stochastic thermodynamics to characterize the cost of operations manipulating information. The main focus of my talk will be dedicated to ... [more ▼] I will start by presenting different ways in which one can use stochastic thermodynamics to characterize the cost of operations manipulating information. The main focus of my talk will be dedicated to explicitly show, using stochastic thermodynamics, in what sense a Maxwell demon effectively modifies the second law of thermodynamics and in what sense it satisfies the second law when the cost for operating the demon is taken into account. A model of coupled quantum dots will be used to illustrate my point. [less ▲] Detailed reference viewed: 61 (0 UL)Thermodynamics of a Physical Model Implementing a Maxwell Demon ; ; et al in Physical Review Letters (2013), 110(4)(040601(5)), 040601-1 We present a physical implementation of a Maxwell demon which consists of a conventional single electron transistor (SET) capacitively coupled to another quantum dot detecting its state. Altogether, the ... [more ▼] We present a physical implementation of a Maxwell demon which consists of a conventional single electron transistor (SET) capacitively coupled to another quantum dot detecting its state. Altogether, the system is described by stochastic thermodynamics. We identify the regime where the energetics of the SET is not affected by the detection, but where its coarse-grained entropy production is shown to contain a new contribution compared to the isolated SET. This additional contribution can be identified as the information flow generated by the ‘‘Maxwell demon’’ feedback in an idealized limit. [less ▲] Detailed reference viewed: 158 (3 UL)Finite-time erasing of information stored in fermionic bits Diana, Giovanni ; ; Esposito, Massimiliano in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013) We address the issue of minimizing the heat generated when erasing the information stored in an array of quantum dots in finite time. We identify the fundamental limitations and trade-offs involved in ... [more ▼] We address the issue of minimizing the heat generated when erasing the information stored in an array of quantum dots in finite time. We identify the fundamental limitations and trade-offs involved in this process and analyze how a feedback operation can help improve it [less ▲] Detailed reference viewed: 72 (3 UL) |
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