Stochastic heat engine powered by active dissipation

Abstract

Thermodynamics of nanoscale devices is an active area of research. Despite their noisy surrounding they often produce mechanical work (e.g. micro-heat engines), display rectified Brownian motion (e.g. molecular motors). This invokes research in terms of experimentally quantifiable thermodynamic efficiencies. Here, a Brownian particle is driven by a harmonic confinement with time-periodic contraction and expansion. The system produces work by being alternately (time-periodically) connected to baths with different dissipations. We analyze the system theoretically using stochastic thermodynamics. Averages of thermodynamic quantities like work, heat, efficiency, entropy are found analytically for long cycle times. Simulations are also performed in various cycle-times. They show excellent agreement with analytical calculations in the long cycle time limit. Distributions of work, efficiency, and large deviation function for efficiency are studied using simulations. We believe that the experimental realization of our model is possible.

Colloidal engines for innovative tests of information thermodynamics

“…Recent studies demonstrated that the stochastic efficiency of Brownian heat engines driven by the non-equilibrium protocol is not bounded and can even exceed Carnot efficiency [51][52][53][54][55][56][57][58]. Here, we study the stochastic efficiency η; À βW=I of the information engine owing to the fluctuations in work and mutual information (Figure 3).…”

Stochastic work extraction in a colloidal heat engine in the presence of colored noise

“…(15) at a given time point t is negligibly small. Quasistatic limit in similar systems was also explored to calculate relevant thermodynamic quantities analytically in [15,30,31]. We note that in the second half of the cycle it is not possible to define an effective temperature T ef f since the heat bath is out of equilibrium.…”

“…While calculating the thermodynamic quantities such as work and heat in quasistatic limit, we will use respective cases in Eq. (15). For instance, the average energy of the trapped particle is given by U = 1 2 kσ x .…”

“…It does not obey FDR and thermodynamic work can be extracted from such a system. Similar system is detailed in [15]. Below we focus on the other combination where γ 2 → γ 1 ≡ γ, D 2 → D 1 τa but with τ a > 0 as in [16,18], such that the bath during compression is still active and thereby remains out of equilibrium to provide persistent, exponentially correlated noise to the colloidal particle immersed into it.…”

“…Earlier it has been demonstrated experimentally that active, self-propelling entities such as live bacteria or micro-algae can affect the fluid viscosity and thereby the dissipation within the fluid, depending on the concentration and swim speed of the suspended microorganisms [2][3][4][5][6]. Motivated by this observation, one can constitute a theoretical model of an active micro heat engine in presence of non-equilibrium heat bath with active dissipation [15].…”