The minimal temperature of Quantum Refrigerators

TL;DR

This paper investigates the fundamental limits of cooling to absolute zero in quantum refrigerators, showing that an energy gap in the working medium prevents reaching zero temperature due to adiabatic constraints.

Contribution

It demonstrates that an uncontrollable energy gap in the working medium sets a non-zero lower bound on achievable temperature in quantum refrigeration.

Findings

An energy gap prevents reaching absolute zero in quantum refrigerators.

Adiabatic following is essential for cooling to zero temperature.

Noise levels influence the minimum achievable temperature.

Abstract

A first principle reciprocating quantum refrigerator is investigated with the purpose of determining the limitations of cooling to absolute zero. We find that if the energy spectrum of the working medium possesses an uncontrollable gap, then there is a minimum achievable temperature above zero. The reason is that such a gap, combined with a negligible amount of noise, prevents adiabatic following during the expansion stage which is necessary condition for reaching T_c --> 0.