title: How small can thermal machines be? The smallest possible refrigerator.
abstract: We investigate the fundamental dimensional limits to thermodynamic machines. In particular, we show that it is possible to construct self-contained refrigerators (i.e., not requiring external sources of work) consisting of only a small number of qubits and/or qutrits. We present three different models, consisting of two qubits, a qubit and a qutrit with nearest-neighbor interactions, and a single qutrit, respectively. We then investigate the fundamental limits to their performance; in particular, we show that it is possible to cool towards absolute zero.
authors.affiliation: Department of Mathematics, University of Bristol, University Walk, Bristol, UK.
authors.forename: Noah
authors.initials: N
authors.lastname: Linden
authors.forename: Sandu
authors.initials: S
authors.lastname: Popescu
authors.forename: Paul
authors.initials: P
authors.lastname: Skrzypczyk