Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session J16: Mpemba Effect: The Path Not TakenLive
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Sponsoring Units: GSNP DCP Chair: Israel Klich, Univ of Virginia |
Tuesday, March 16, 2021 3:00PM - 3:12PM Live |
J16.00001: Small Systems Warm up Faster Than They Cool Down Alessio Lapolla, Aljaz Godec According to the celebrated laws of linear irreversible thermodynamics the rate of relaxation of an extensive thermodynamic observable to its equilibrium value depends linearly on the magnitude of the departure from equilibrium, and is independent of the direction of the departure. However, these laws rely on the assumption of 'local thermodynamic equilibrium' which is expected to break down for small systems quenched far from equilibrium. |
Tuesday, March 16, 2021 3:12PM - 3:24PM Live |
J16.00002: Lindblad dissipative dynamics in the presence of phase coexistence ANDREA NAVA, Michele Fabrizio We investigate the dissipative dynamics yielded by the Lindblad equation within the coexistence region around a first-order phase transition. In particular, we consider an exactly solvable, fully connected quantum Ising model with n-spin exchange (n > 2) — the prototype of quantum first-order phase transitions — and several variants of the Lindblad equations to describe the dissipative dynamics in the presence of phase coexistence. Metastability in Markovian open quantum systems turns out to be a nontrivial problem due to the separation of timescales in the dissipative dynamics. Typically, the Lindblad equation is able to describe the short-time dynamics during which the system relaxes to a metastable state, while it fails to describe the long-time ergodic dynamics that drives relaxation to the true equilibrium state. We show how to describe the full dynamics in terms of an effective Lindblad equation valid in both regimes. We show that physically sound results, including exotic nonequilibrium phenomena such as the Mpemba effect, can be obtained only when the Lindblad equation involves jump operators defined for each of the coexisting phases, whether stable or metastable. |
Tuesday, March 16, 2021 3:24PM - 3:36PM Live |
J16.00003: Mpemba effect in systems with boundary coupling Gianluca Teza, Ran Yaacoby, Oren Raz The Mpemba effect is a counterintuitive phenomenon where under proper conditions, a hot system cools down faster than an initially cold system when quenching both to an even colder bath. The nonequilibrium thermodynamics framework provides a comprehensive high-level characterization of this phenomenon, which has been observed in systems including water, magnetic alloys, polymers, granular gasses and colloidal systems. However, in most experiments the system is coupled to the heath-bath only through its boundaries, whereas the theoretical studies presented so far assumed bulk coupling, hindering the adequacy of this description for large sized systems. |
Tuesday, March 16, 2021 3:36PM - 3:48PM Live |
J16.00004: Mpemba effect in molecular fluids: a kinetic theory approach Antonio Prados, Antonio Patrón, Bernardo Sánchez-Rey, Alberto Megías, Andres Santos We investigate the emergence of the Mpemba effect in a molecular fluid with nonlinear viscous drag. Thus, fluid particles undergo non-linear Brownian motion and the fluid is described by an Enskog--Fokker--Planck equation within the framework of kinetic theory. The Mpemba effect emerges as a consequence of the coupling of the evolution equations of the temperature and the excess kurtosis. The smallness of the latter makes it possible to develop an approximate theory that gives a quantitative account of the conditions for the Mpemba effect to come about. Moreover, we discuss how the system has to be previously aged to observe the Mpemba effect. Other memory phenomena, like the Kovacs hump, can also be described with a similar approach. |
Tuesday, March 16, 2021 3:48PM - 4:00PM Not Participating |
J16.00005: The Mpemba effect in granular fluids as a thermal memory effect Francisco Vega Reyes The Mpemba effect has been described in several systems, such as a water, spin glasses, granular gases and Markov chains. Originally, the Mpemba effect consists in an abnormally faster cooling process towards a stationary temperature for a system, as compared to an initially colder but otherwise identical system. |
Tuesday, March 16, 2021 4:00PM - 4:12PM Live |
J16.00006: Large Mpemba-like effect in a gas of inelastic rough hard spheres Aurora Torrente, Miguel Angel Lopez-Castano, Antonio Lasanta Becerra, Francisco Vega-Reyes, Antonio Prados, Andres Santos A giant Mpemba-like effect emerges in a uniformly heated gas of inelastic rough hard spheres, where the initially hotter sample cools sooner than the colder one, even when the initial temperatures differ by more than one order of magnitude. In order to understand this behavior, it suffices to consider the simplest Maxwellian approximation for the velocity distribution in a kinetic approach. The largeness of the effect stems from the fact that the rotational and translational temperatures, which obey two coupled evolution equations, are comparable, and it increases with higher inelasticity and lower roughness of the particles. Our theoretical predictions agree very well with molecular dynamics and direct simulation Monte Carlo data. |
Tuesday, March 16, 2021 4:12PM - 4:24PM Live |
J16.00007: Remarkable aspects in Stochastic Thermodynamics Carlos Fiore Over the last two decades, stochastic thermodynamics has become one of the main cornestones of the modern statistical mechanics. Due to its large applicability, it has been employed for the description of several problems, such as efficiency of thermal engines at finite time, phase transitions, chemical reactions, uncertainties relations and others. Close to equilibrium, one can use this framework to determine the thermodynamic fluxes, such as heat and work, and showing that they satisfy general properties, such as Onsager and the Green-Kubo relations. In this talk, we present some recent results about stochastic thermodynamics, including a (general) linear description of markovian systems in contact with multiple reservoirs, general descriptions at nonequilibrium phase transition regimes and efficiency of thermal engines subject to sequential periodic drivings. |
Tuesday, March 16, 2021 4:24PM - 4:36PM Live |
J16.00008: Quantitative comparison of different time-periodic Thermodynamic Uncertainty Relations Pedro Harunari, Carlos Fiore, Karel Proesmans Thermodynamic Uncertainty Relations (TUR) comprise a general bound for fluxes in nonequilibrium processes [1], they represent a trade-off between signal and noise for steady state thermodynamic fluxes (e.g. particle flow, heat delivered to a thermal reservoir, substrate molecules consumption) in Markov processes. These quantities fluctuate and the TURs relate their average and variance to the entropy production of the process, which is a measure of irreversibility and therefore the relation can also be rearranged to bound the efficiency of mesoscopic engines. |
Tuesday, March 16, 2021 4:36PM - 4:48PM Live |
J16.00009: Current large deviations of nonreversible diffusions Francesco Coghi, Raphael Chetrite, Hugo Touchette It is known that calculating means by sampling a Gibbs distribution using Markov chain Monte Carlo algorithms can be made computationally quicker by adding nonreversible transitions or drift terms. In this talk I will give a physical interpretation of this accelerated convergence. Using the level 2.5 of large deviations, accelerated convergence is guaranteed because additional current large deviation costs affect mean fluctuations when compared to the reversible case. I illustrate this general result, and some interesting bounds, for the simple diffusion on the circle and two versions of the Ornstein-Uhlenbeck process in two dimensions. |
Tuesday, March 16, 2021 4:48PM - 5:00PM Live |
J16.00010: Non-equilibrium universality in non-reciprocal coupled Ising models Jeremy Young, Alessio Chiocchetta, Mohammad Maghrebi While the physics of equilibrium phase transitions is well established, a full understanding of non-equilibrium phase transitions is still missing. On the other hand, non-equilibrium matter is increasingly realized in a variety of fields, from active matter to driven-dissipative quantum systems. In this talk, I will introduce a non-equilibrium variant of the Ashkin-Teller model in which two species of Ising spins experience a non-reciprocal coupling, explicitly breaking detailed balance and the equilibrium condition. Using Monte Carlo techniques, we show that this model possesses a multicritical point that exhibits exotic critical behavior, consistent with recent field-theoretical predictions. In particular, we show the extreme breakdown of the fluctuation-dissipation theorem, which is captured by the emergence of two distinct anomalous dimensions for the correlation and response functions with the former assuming a negative value, a feature with no counterpart in equilibrium. |
Tuesday, March 16, 2021 5:00PM - 5:12PM Live |
J16.00011: Finite-time thermodynamic processes of a spin-one quantum electric dipole system Yigermal Bassie We take a collection of large non-interacting spin one particles, each having an electric dipole of magnitude, D, in contact with a heat reservoir at temperature T. We apply a strong static electric field, E0, to the system along a z-axis causing three level split energy values. In addition to the strong electric field, applying a weak AC electric field in the xy−plane inducedes transitions between the three levels. Through a given protocol,ζ(t), the system is taken from an initial thermodynamic equilibrium state F(T,τi) to a final non-equilibrium state with parameter ζf. We analytically obtain the expressions for the probability amplitudes for a transition from one particular initial state to the other two final states. This will enable us to find the work distributions of a finite-time process of taking the system from one initial state to either of the two final states of the three-level system. This finite-time non-equilibrium process will then enable us to extract equilibrium thermodynamic quantities like free energy from non-equilibrium process. We empirically obtain the average work of the three-level system as afunction of the frequency of AC electric field and time around the optimum frequency. |
Tuesday, March 16, 2021 5:12PM - 5:24PM Live |
J16.00012: Higher-order Mpemba effect in a colloidal system Avinash Kumar, John Bechhoefer The Mpemba effect is observed if an initially hot system cools faster than an initially warm system when coupled to the same thermal bath. Previous experiments on the Mpemba effect were performed in a system where a Brownian colloidal particle is subjected to forces from an asymmetric double-well potential. In this system, the presence of anomalous relaxation traces back to a non-monotonic behavior in temperature of the amplitude 2 of the second eigenfunction of the Fokker-Planck operator. Here we present observations showing that anomalous relaxation is present in a symmetric potential. By symmetry, the quantity 2 vanishes in such a potential, and the particle dynamics are governed by the next higher-order term, 3. The non-monotonic temperature dependence of 3 leads to this new, higher-order Mpemba effect. |
Tuesday, March 16, 2021 5:24PM - 5:36PM Live |
J16.00013: Mpemba effect and anomalous relaxation in 1D and 2D many body Ising models Emanuel Mompó, Antonio Lasanta Becerra, Victor Martin-Mayor, Jesús Salas Several out-of-equilibrium phenomena, such as the Mpemba and Kovacs effects, have gained interest in recent years. Though counter-intuitive, these effects can pave the way to useful applications, such as precooling strategies for faster heating. These phenomena have been shown to happen in granular gasses, spin glasses, and colloidal systems. Moreover, a Mpemba-like effect has also been found in water. |
Tuesday, March 16, 2021 5:36PM - 5:48PM Live |
J16.00014: Engineered swift equilibration on generic configuration spaces Adam Frim, Adrianne Zhong, Shi-Fan Chen, Dibyendu Mandal, Michael Robert DeWeese Engineered swift equilibration (ESE) is a class of driving protocols that enforce an internal equilibrium distribution at all times during rapid state transformation of open, classical non-equilibrium systems. ESE protocols have previously been derived and experimentally realized for Brownian particles in simple, one-dimensional, time-varying trapping potentials. We extend the ESE framework to overdamped Brownian particles described by generic configuration spaces. We illustrate our results numerically for specific example systems not amenable to previous techniques. Our approach may be used to impose internal equilibrium dynamics in a wide variety of experimental settings. |
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