Alladi Ramakrishnan Hall

Quantum speed limit constraints on a nanoscale autonomous refrigerator

Avijit Misra

IMSc

Quantum speed limit, furnishing a lower bound on the required time for
the evolution of a quantum system through the state space, imposes an
ultimate natural limitation on the dynamics of physical devices.
Quantum absorption refrigerators, on the other hand, have attracted a
great deal of attention in the last few years. In this article, we
discuss the effects of the quantum speed limit on the performance of a
quantum absorption refrigerator. In particular, we show that there
exists a trade-off relation between the steady cooling rate of the
refrigerator and the minimum time taken to reach the steady state.
Based on this, we define a figure of merit called "bounding second
order cooling rate" and show that this scales linearly with the
unitary interaction strength among the constituent qubits. We also
study the increase of bounding second order cooling rate with the
thermalization strength. We subsequently demonstrate that coherence in
the initial three-qubit system can significantly increase the bounding
second order cooling rate. We study the efficiency of the refrigerator
at maximum bounding second order cooling rate and, in a limiting case,
we show that the efficiency at maximum bounding second order cooling
rate is given by a simple formula reminiscent of the Curzon-Ahlborn
relation.

Ref: arXiv:1711.10813