相关论文: Feynman's ratchet and pawl: an exactly solvable mo…

Feynman's ratchet and pawl is a paradigmatic model for energy conversion using thermal fluctuations in the mesoscopic regime. Here, we optimize the power output of the ratchet as a heat engine in the high temperatures limit, and derive the…

We present a model for a thermal Brownian motor based on Feynman's famous ratchet and pawl device. Its main feature is that the ratchet and the pawl are in different thermal baths and connected by an harmonic spring. We simulate its…

Feynman's ratchet is a microscopic machine in contact with two heat reservoirs, at temperatures $T_A$ and $T_B$, that was proposed by Richard Feynman to illustrate the second law of thermodynamics. In equilibrium ($T_A=T_B$), thermal…

We study a class of heat engines including Feynman's ratchet, which exhibits a directed motion of a particle in nonequilibrium steady states maintained by two heat baths. We measure heat transfer from each heat bath separately, and average…

The maximum power of Feynman's ratchet as a heat engine and the corresponding efficiency ($\eta_\ast$) are investigated by optimizing both the internal parameter and the external load. When a perfect ratchet device (no heat exchange between…

We show that a mesoscopic system such as Feynman's ratchet may operate as a heat pump, and clarify a underlying physical picture. We consider a system of a particle moving along an asymmetric periodic structure . When put into a contact…

We estimate the performance of Feynman's ratchet at given values of the ratio of cold to hot reservoir temperatures ($\theta$) and the figure of merit (efficiency in the case of engine and coefficienct of performance in the case of…

We present a simple kinematic model of a non-equilibrium steady state device, which can operate either as a heat engine or as a refrigerator. The model is composed of two or more scattering channels where the motion is fully described by…

We describe a simple and solvable model of a device that -- like the "neat-fingered being" in Maxwell's famous thought experiment -- transfers energy from a cold system to a hot system by rectifying thermal fluctuations. In order to…

Motivated by recent studies on models of particle and heat quantum pumps, we study similar simple classical models and examine the possibility of heat pumping. Unlike many of the usual ratchet models of molecular engines, the models we…

Stochastic model of the Feynman-Smoluchowski ratchet is proposed and solved using generalization of the Fick-Jacobs theory. The theory fully captures nonlinear response of the ratchet to the difference of heat bath temperatures. The ratchet…

A Stirling engine of the type used for demonstration purposes has been outfitted with a pair of sensors that measure pressure and piston displacement when the engine is operating with a small temperature difference between the hot and cold…

We discuss two-dimensional diffusion of a Brownian particle confined to a periodic asymmetric channel with soft walls modeled by a parabolic potential. In the channel, the particle experiences different noise intensities, or temperatures,…

We describe an exactly solvable model which illustrates the Fluctuation Theorem and other predictions for systems evolving far from equilibrium. Our model describes a particle dragged by a spring through a thermal environment. The rate at…

We study the flashing ratchet model of a Brownian motor, which consists in cyclical switching between the Fokker-Planck equation with an asymmetric ratchet-like potential and the pure diffusion equation. We show that the motor really…

Several stochastic models called thermal ratchet models have been recently proposed to analyze the motor proteins such as myosin and kinesin,etc. We propose a method to study the energetics of those models, and show how the rate of energy…

Stochastic heat engines are devices that generate work from random thermal motion using a small number of highly fluctuating degrees of freedom. Proposals for such devices have existed for more than a century and include the Maxwell demon…

We propose a simple quantum mechanical model describing the time dependent diffusion current between two fermion reservoirs that were initially disconnected and characterized by different densities or chemical potentials. The exact,…

Cats use the connection governing parallel transport in the space of shapes to land safely on their feet. Here we argue that this connection also explains the impressive performance of molecular motors by enabling molecules to evade…

The concept of thermal ratchets is extended to the system governed by quantum mechanics. We study a tight-binding model with an asymmetric periodic potential contacting with a heat bath under an external oscillating field as a specific…