Quantum absorption refrigerator with trapped ions

A remarkable progress has recently been achieved in studies of thermodynamics and heat machines, with experiments probing down to micro and nano-scale systems such as the single Brownian particle [1], as well as the single atom [2]. However, despite several theoretical proposals [3, 4], implementation of heat machines in the fully quantum regime remains a challenge. We report on an experimental realization of a quantum absorption refrigerator in a system of the three trapped
¹⁷¹
Yb
⁺
ions. The normal modes of motion are coupled by a trilinear Hamiltonian ab
^†
c
^†
and represent “hot”, “work” and “cold” bodies of the refrigerator (Figure 1). We investigate the equilibrium properties of the refrigerator, and demonstrate the absorption refrigeration effect with the modes being prepared in thermal states.