Bulletin of the American Physical Society
APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017; New Orleans, Louisiana
Session Y52: Non-equilibrium Thermodynamics in Quantum Information Theory |
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Sponsoring Units: GSNP GQI Chair: Sebstian Deffner, University of Maryland Baltimore County Room: 399 |
Friday, March 17, 2017 11:15AM - 11:27AM |
Y52.00001: Anomalous cooling and heating -- the Mpemba effect and its inverse Zhiyue Lu, Oren Raz Under certain conditions, it takes a shorter time to cool a hot object than to cool the same object initiated at a lower temperature. This counter-intuitive phenomenon -- the “Mpemba Effect”, has been observed in a variety of systems. So far, no generic mechanism was suggested to explain this effect. In the theoretical framework of non-equilibrium thermodynamics, we construct a model to describe this effect and illustrates the fundamental principles behind it. In addition, we predict and demonstrate an inverse Mpemba effect: it can take a shorter time to heat a cold object than a warmer one. We derive sufficient conditions for the occurrences of both the forward and the inverse Mpemba effects, and suggest experiments to further study the non-equilibrium nature of these effects. [Preview Abstract] |
Friday, March 17, 2017 11:27AM - 11:39AM |
Y52.00002: A subextensive bound on entropy production in the adiabatic limit Benjamin Machta Biological and engineered systems operate by coupling function to the transfer of heat and/or particles down a thermal or chemical gradient. In idealized \textit{deterministically} driven systems, thermodynamic control can be exerted reversibly, with no entropy production, as long as the rate of the protocol is made slow compared to the equilibration time of the system. Here we consider \textit{fully realizable, entropically driven} systems where the control parameters themselves obey rules that are reversible and that acquire directionality in time solely through dissipation. I will show that when such a system moves in a directed way through thermodynamic space, it must produce entropy that is on average larger than its generalized displacement as measured by the Fisher information metric. This distance measure is sub-extensive but cannot be made small by slowing the rate of the protocol. (see Phys. Rev. Lett. 115, 260603) I will discuss the application of this bound to the question of the minimum energetic cost of a computation. [Preview Abstract] |
Friday, March 17, 2017 11:39AM - 11:51AM |
Y52.00003: Field Theoretic Description of Non-Equilibrium Chemical Work Relations Jonathan Pham, Benjamin Vollmayr-Lee We develop a field theoretic description of nonequilibrium chemical work relations, generalizing the well-known Jarzynski equality. We consider classical particles undergoing chemical reactions in a local potential. The particles are coupled to a chemostat and a thermal reservoir, with dynamics governed by detailed balance. Work protocols are imposed by varying the local potential, and work relations appear simply as a result of a gauge-like transformation combined with time reversal. We then generalize the method to chemical systems which violate detailed balance. [Preview Abstract] |
Friday, March 17, 2017 11:51AM - 12:03PM |
Y52.00004: Non-equilibrium steady states in ``PT-symmetric'' classical chains Danny Sweeney, Donald Priour, Andrew Harter, Yogesh Joglekar Open systems with balanced, spatially separated gain and loss undergo a transition, called parity-time (PT) symmetry breaking transition, that is absent in their closed counterparts. This transition is manifest in the system changing from a quasi-equilibrium state to a state far removed from equilibrium. We investigate a chain of classical particles in the presence of a localized loss and a stochastic drive that is spatially separated from the loss site. This setup generalizes the traditional Langevin noise approach for modeling thermalization in a chain. We analytically and numerically show that the system can be in either in a non-equilibrium steady-state or does not thermalize. We further show that the steady-state, non-constant temperature profile of the chain can be engineered by appropriate choices of the loss location and the stochastic drive location. This work was supported by NSF grant no. DMR-1054020. [Preview Abstract] |
Friday, March 17, 2017 12:03PM - 12:15PM |
Y52.00005: Equilibration and non-equilibrium steady states in PT-symmetric Toda lattice Andrew Harter, Yogesh Joglekar, Avadh Saxena The Toda lattice is a classical discrete integrable model, describing a chain of particles that interact through an exponentially decaying, pairwise potential. It also supports soliton solutions. We consider the fate of this lattice in the presence of localized, spatially separated, balanced drag (loss) and drive (gain). Such systems with balanced gain and loss undergo a transition, the so called parity-time (PT) symmetry breaking transition, from a quasi-equilibrium state to a state that is far removed from equilibrium. We determine the threshold for such a transition in the presence of stochastic and deterministic driving, and study the robustness of our results in the presence of different boundary conditions. [Preview Abstract] |
Friday, March 17, 2017 12:15PM - 12:27PM |
Y52.00006: Mapping current fluctuations of stochastic pumps to nonequilibrium steady states. Grant Rotskoff We show that current fluctuations in stochastic pumps can be robustly mapped to fluctuations in a corresponding time-independent non-equilibrium steady state. We thus refine a recently proposed mapping so that it ensures equivalence of not only the averages, but also the optimal representation of fluctuations in currents and density. Our mapping leads to a natural decomposition of the entropy production in stochastic pumps, similar to the ``housekeeping'' heat. As a consequence of the decomposition of entropy production, the current fluctuations in weakly perturbed stochastic pumps satisfy a universal bound determined by the steady state entropy production. [Preview Abstract] |
Friday, March 17, 2017 12:27PM - 12:39PM |
Y52.00007: Marginal fluctuation theorems and local equilibrium Matteo Polettini, Bernhard Altaner, Massimiliano Esposito |
Friday, March 17, 2017 12:39PM - 12:51PM |
Y52.00008: Abstract Withdrawn The Gallavotti-Cohen fluctuation relation (FR) posits a specific symmetry between positive and negative fluctuations in entropy production, or a related quantity (e.g power) for systems in non-equilibrium stationary state. Successful tests in a variety of systems suggest the FR may be more generally applicable than the conditions under which it was originally derived. Systems where the FR fails are therefore valuable for the insight they provide into the FR’s general success. It has recently been suggested that ``active matter" should not satisfy the fluctuation-dissipation theorem or FR. We experimentally test this possibility in a system of active camphor boats, self-propelled by surface tension gradients at air-water interfaces. The boats interact {\it via} short-range capillary attraction which competes with long-range surface tension mediated repulsion. Tuning interaction strength with number density, we test the FR through the statistics of power as one goes from a free non-interacting camphor boat, through a few weakly interacting boats to several, strongly interacting boats. We present preliminary results of our experiments and data analysis. |
Friday, March 17, 2017 12:51PM - 1:03PM |
Y52.00009: Thermodynamic geometry of minimum-dissipation driven barrier crossing David Sivak, Gavin Crooks We explore the thermodynamic geometry of a simple system that models the bistable dynamics of nucleic acid hairpins in single molecule force-extension experiments. Near equilibrium, optimal (minimum-dissipation) driving protocols are governed by a generalized linear response friction coefficient. Our analysis demonstrates that the friction coefficient of the driving protocols is sharply peaked at the interface between metastable regions, which leads to minimum-dissipation protocols that drive rapidly within a metastable basin, but then linger longest at the interface, giving thermal fluctuations maximal time to kick the system over the barrier. Intuitively, the same principle applies generically in free energy estimation (both in steered molecular dynamics simulations and in single-molecule experiments), provides a design principle for the construction of thermodynamically efficient coupling between stochastic objects, and makes a prediction regarding the construction of evolved biomolecular motors. [Preview Abstract] |
Friday, March 17, 2017 1:03PM - 1:15PM |
Y52.00010: Stochastic thermodynamics and fluctuation theorems of active Brownian dynamics Dibyendu Mandal, Katherine Klymko Active biological systems reside far from equilibrium, dissipating heat even in their steady state, and thus requiring an extension of the conventional equilibrium thermodynamics and statistical mechanics. In this study, we have extended the emerging framework of stochastic thermodynamics to active Brownian particles. In particular, for the active Ornstein-Uhlenbeck model, we have provided consistent definitions of thermodynamic quantities like work, energy, and entropy at the level of single, stochastic trajectories and derived all the major integral fluctuation relations, for total entropy production, excess entropy production, and housekeeping heat. We have developed the equivalent of the Clausius inequality and it reflects the underlying non-Hamiltonian nature of the dynamics. For this active, overdamped model, we have also discovered some subtleties in the detailed fluctuation theorems for the excess and the housekeeping heat that are absent in passive overdamped dynamics. We have illustrated our results with explicit numerical studies. These studies will ultimately reflect on the thermodynamic efficiency of active, biological processes. [Preview Abstract] |
Friday, March 17, 2017 1:15PM - 1:27PM |
Y52.00011: Evaluating linear response in active systems with no perturbing field: Application to the calculation of an effective temperature Grzegorz Szamel We present a method for the evaluation of time-dependent linear response functions for systems of active particles propelled by a persistent (colored) noise from unperturbed simulations. The method is inspired by the Malliavin weights sampling method proposed earlier for systems of (passive) Brownian particles. We illustrate our method by evaluating a linear response function for a single active particle in an external harmonic potential. As an application, we calculate the time-dependent mobility function and an effective temperature, defined through the Einstein relation between the self-diffusion and mobility coefficients, for a system of active particles interacting via a screened-Coulomb potential. We find that this effective temperature decreases with increasing persistence time of the self-propulsion. Initially, for not too large persistence times, it changes rather slowly, but then it decreases markedly when the persistence length of the self-propelled motion becomes comparable with the particle size. [Preview Abstract] |
Friday, March 17, 2017 1:27PM - 1:39PM |
Y52.00012: Extracting work from gradients in active motion Nitzan Razin, Raphael Voituriez, Jens Elgeti, Nir Gov We study how the active motion of particles can cause a pressure gradient on a large inert object that moves it to a target position. This is motivated by recent experiments, which showed that the nucleus of a mouse oocyte (immature egg cell) moves from the cortex to the center due to a pressure gradient exerted by the active motion of vesicles. We calculate the force on a symmetric inert object inside a system of active particles with position dependent motion parameters, in one and two dimensions. We characterize a system where such a force exists, both in terms of the model parameters and in terms of measurable quantities: the density, velocity and pressure profiles. [Preview Abstract] |
Friday, March 17, 2017 1:39PM - 1:51PM |
Y52.00013: Realization of a Brownian Motor through Real Time Feedback Control Govind Paneru, Dong yun Lee, Hyuk Kyu Pak Recent studies on the relation between information and thermodynamics showed that in the presence of a feedback control, an information quantity known as mutual information, should be included in describing non-equilibrium dynamics of fluctuating systems. Here, we have designed an information engine that consists of a colloidal particle in a single heat bath. The engine is capable of transporting the particle along one direction by utilizing the information about the microscopic state of the system. This one way transportation of the particle behaves as a Brownian motor. We measured the average extracted work for various cycle time $\tau $ and found that the average extracted work per engine cycle increases with increasing $\tau $, and for large $\tau $, our system is capable of achieving an upper bound of the extractable work. We have also investigated the relation between the average transport velocity and the extracted work. For a given $\tau $, the average transport velocity is limited by the amount of extracted work or the net available information. [Preview Abstract] |
Friday, March 17, 2017 1:51PM - 2:03PM |
Y52.00014: Achieving swift equilibration of a Brownian particle using flow-fields Ayoti Patra, Christopher Jarzynski Can a system be driven to a targeted equilibrium state on a timescale that is much shorter than its natural equilibration time? In a recent experiment, the swift equilibration of an overdamped Brownian particle was achieved by use of an appropriately designed, time-dependent optical trap potential (Nat. Phys. 12, 843-846, 2016). Motivated by these results, we develop a general theoretical approach for guiding an ensemble of Brownian particles to track the instantaneous equilibrium distribution of a desired potential $U(q,t)$. In our approach, we use flow-fields associated with the parametric evolution of the targeted equilibrium state to construct an auxiliary potential $\bar{U}(q,t)$, such that dynamics under the composite potential $U(t) +\bar{U}(t)$ achieves the desired evolution. Our results establish a close connection between the swift equilibration of Brownian particles, quantum shortcuts to adiabaticity, and the dissipationless driving of a classical, Hamiltonian system. [Preview Abstract] |
Friday, March 17, 2017 2:03PM - 2:15PM |
Y52.00015: Stochastic processes on multiple scales: averaging, decimation and beyond. Stefano Bo, Antonio Celani The recent advances in handling microscopic systems are increasingly motivating stochastic modeling in a large number of physical, chemical and biological phenomena. Relevant processes often take place on widely separated time scales. In order to simplify the description, one usually focuses on the slower degrees of freedom and only the average effect of the fast ones is retained. It is then fundamental to eliminate such fast variables in a controlled fashion, carefully accounting for their net effect on the slower dynamics. We shall present how this can be done by either decimating or coarse-graining the fast processes and discuss applications to physical, biological and chemical examples. With the same tools we will address the fate of functionals of the stochastic trajectories (such as residence times, counting statistics, fluxes, entropy production, etc.) upon elimination of the fast variables. In general, for functionals, such elimination can present additional difficulties. In some cases, it is not possible to express them in terms of the effective trajectories on the slow degrees of freedom but additional details of the fast processes must be retained. We will focus on such cases and show how naive procedures can lead to inconsistent results. [Preview Abstract] |
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