Talks

Refrigerators are inseparable from everyday life, industrial manufacturing, and research labs. In this talk, I will present our recent investigation on the refrigerator working between a finite-sized cold heat sink (which means that the heat capacity of the cold bath is finite) and an infinite-sized hot reservoir (environment). We assume that initially the finite-sized cold heat sink at temperature Ti ≤ Th, where Th is the hot reservoir temperature. By consuming the input work/power, the refrigerator transfers the heat from a finite-sized cold sink to the hot heat reservoir. Hence, the temperature of the finite-sized cold heat sink starts to decrease until it reaches the desired low-temperature Tf. By minimizing the input work in this heat transport process, we find the optimal path for temperature rate. We also calculate the coefficient of performance of the refrigerator.

We investigate the dynamics of subsystem particle number fluctuations in a long-range system with power-law decaying hopping strength and subjected to a local dephasing at every site. We introduce an efficient bond length representation for the four-point correlator, enabling the large-scale simulation of the dynamics of particle number fluctuations from translationally invariant initial states. Our results show that the particle number fluctuation dynamics exhibit one-parameter Family-Vicsek scaling, with superdiffusive scaling exponents for long-range hopping exponent values less than 3/2 and diffusive scaling exponents for values greater or equal to 3/2. Finally, exploiting the bond-length representation, we provide an exact analytical expression for the particle number fluctuations and their scaling exponents in the short-range limit.

We explore the phenomena of prethermalization in a many-body classical system of rotors under aperiodic drives characterised by waiting time distribution (WTD), where the waiting time is defined as the time between two consecutive kicks. We consider here two types of aperiodic drives: random and quasi-periodic. We observe a short-lived pseudo-thermal regime with algebraic suppression of heating for the random drive where WTD has an infinite tail, as observed for Poisson and binomial kick sequences. On the other hand, quasi-periodic drive characterised by a WTD with a sharp cut-off, as observed for Thue-Morse sequence of kick, leads to prethermal region where heating is exponentially suppressed. The kinetic energy growth is analyzed using an average surprise associated with WTD quantifying the randomness of drive. In all of the aperiodic drives we obtain the chaotic heating regime for late time, however, the diffusion constant gets renormalized by the average surprise of WTD in comparison to the periodic case.