1,721,255 research outputs found
Reply to: 'Comment on 'Out-of-equilibrium Frenkel-Kontorova model' (Imparato A 2021 J. Stat. Mech
No full textIn their comment Quapp and Bofill (QB) [1] raise concerns regarding the phases of the Frenkel–Kontorova (FK) model that I recently considered in [2]
Out-of-equilibrium Frenkel-Kontorova model
No full textA 1D model of interacting particles moving over a periodic substrate and in a position dependent temperature profile is considered. When the substrate and the temperature profile are spatially asymmetric a centre-of-mass velocity develops, corresponding to a directed transport of the chain. This autonomous system can thus transform heath currents into motion. The model parameters can be tuned such that the particles exhibit a crossover from an ordered configuration on the substrate to a disordered one, the maximal motor effect being reached in such a disordered phase. In this case the manybody motor outperforms the single motor system, showing the great importance of collective effects in microscopic thermal devices. Such collective effects represent thus a free resource that can be exploited to enhance the dynamic and thermodynamic performances in microscopic machines
Maximum power operation of interacting molecular motors
No full textWe study the mechanical and thermodynamic properties of different traffic models for kinesin which are relevant in biological and experimental contexts. We find that motor-motor interactions play a fundamental role by enhancing the thermodynamic efficiency at maximum power of the motors, as compared to the noninteracting system, in a wide range of biologically compatible scenarios. We furthermore consider the case where the motor-motor interaction directly affects the internal chemical cycle and investigate the effect on the system dynamics and thermodynamics
Efficiency at maximum power of motor traffic on networks
No full textWe study motor traffic on Bethe networks subject to hard-core exclusion for both tightly coupled one-state machines and loosely coupled two-state machines that perform work against a constant load. In both cases we find an interaction-induced enhancement of the efficiency at maximum power (EMP) as compared to noninteracting motors. The EMP enhancement occurs for a wide range of network and single-motor parameters and is due to a change in the characteristic load-velocity relation caused by phase transitions in the system. Using a quantitative measure of the trade-off between the EMP enhancement and the corresponding loss in the maximum output power we identify parameter regimes where motor traffic systems operate efficiently at maximum power without a significant decrease in the maximum power output due to jamming effects
Out-of-Equilibrium Clock Model at the Verge of Criticality
No full textWe consider an out-of-equilibrium lattice model consisting of 2D discrete rotators, in contact with heat reservoirs at different temperatures. The equilibrium counterpart of such a model, the clock model, exhibits three phases: a low-temperature ordered phase, a quasiliquid phase, and a high-temperature disordered phase, with two corresponding phase transitions. In the out-of-equilibrium model the simultaneous breaking of spatial symmetry and thermal equilibrium gives rise to directed rotation of the spin variables. In this regime the system behaves as a thermal machine converting heat currents into motion. In order to quantify the susceptibility of the machine to the thermodynamic force driving it out of equilibrium, we introduce and study a dynamical response function. We show that the optimal operational regime for such a thermal machine occurs when the out-of-equilibrium disturbance is applied around the critical temperature at the boundary between the first two phases, namely, where the system is mostly susceptible to external thermodynamic forces and exhibits a sharper transition. We thus argue that critical fluctuations in a system of interacting motors can be exploited to enhance the machine overall dynamic and thermodynamic performances
Quantum duets working as autonomous thermal motors
No full textWe study the dynamic properties of a thermal autonomous machine made up of two quantum Brownian particles, each of which is in contact with an environment at different temperature and moves on a periodic sinusoidal track. When such tracks are shifted, the center of mass of the system exhibits a nonvanishing velocity, for which we provide an exact expression in the limit of small track undulations. We discuss the role of the broken spatial symmetry in the emergence of directed motion in thermal machines. We then consider the case in which external deterministic forces are applied to the system, and we characterize its steady-state velocity. If the applied external force opposes the system motion, work can be extracted from such a steady-state thermal machine, without any external cyclic protocol. When the two particles are not interacting, our results reduce to those of Fisher and Zwerger [Phys. Rev. B 32, 6190 (1985)PRBMDO0163-182910.1103/PhysRevB.32.6190] and Aslangul, Pottier, and Saint-James [J. Phys. France 48, 1093 (1987)JOPQAG0302-073810.1051/jphys:019870048070109300] for a single particle moving in a periodic tilted potential. We finally use our results for the motor velocity to check the validity of the quantum molecular dynamics algorithm in the nonlinear, nonequilibrium regime
Work probability distribution in single-molecule experiments
No full textWe derive and solve a differential equation satisfied by the
probability distribution of the work done on a single biomolecule
in a mechanical unzipping experiment. The unzipping is described
as a thermally activated escape process in an energy landscape.
The Jarzynski equality is recovered as an identity, independent
of the pulling protocol. This approach allows one to easily
evaluate, by numerical integration, the work distribution, once a
few parameters of the energy landscape are known
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