Research

Heat transport in a harmonic chain of active particles: Heat flows across a thermal conductor connected to two heat baths of unequal temperatures. It was known that the heat current for a harmonic chain of passive particles is proportional to the temperature difference (obeying Fourier's law of heat conduction). In this study, we study the role of active particles (AOUPs) on the heat current and its fluctuations. It turns out that the mean of the left-current reduces and the fluctuations becomes larger as the activity of the particles increases.  See details here. 

Bound on the speed limit: Thermodynamic systems move from one state to another in the probability space in a finite time bounded by the thermodynamic cost function. In our recent study, we refined this bound using a Milne's inequality. See details here.

Stochastic resetting: Stochastic resetting is a mechanism where a process is interrupted and reallocated to a specific location. The system reaches a non-equilibrium steady state and exhibits finite mean first passage time. 

The process under stochastic resetting violates micro-reversibility. Nevertheless, applying some external protocol, one can measure fluctuations of dynamic observables (e.g., heat, entropy, work, etc.)  and they follow universal relations of the non-equilibrium statistical physics.  

Hitherto, the resetting mechanism has been introduced as an instantaneous process. In a new setup, one can also impose a finite-time resetting protocol to a stochastic system using an external potential. 

Thermodynamic uncertainty relations: The precision of thermodynamic current 'J' [i.e., Var(J)/Mean(J)*Mean(J)] is bounded by the entropy production in the non-equilibrium steady state. Such bound can be saturated in the vanishing limit of the observation time and that helps to infer the exact estimate of the dissipation. 

Applying the time-dependent protocol to the systems, we find an extension of the thermodynamic uncertainty relations in a linear system for the particle position and current.

Fluctuation theorem (FT) for partial system:  In non-equilibrium steady state, FT measures the asymmetry between the probability of the positive and that of negative entropy production. When the observed system is coupled with another hidden system, one can find a deviation from the steady-state fluctuation theorem even in the weak coupling limit (See EPL, JSTAT). Nonetheless, such weak coupling effect can be nullified using a harmonic confinement (full article).    

Stochastic efficiency: Thermal fluctuations play a significant role in the case of small-scale engines/devices. Consequently, the efficiency, the ratio of output power and the input power,  is a stochastic quantity. The probability density function and the large deviation function show a non-trivial behavior. One can find these results here and here.