



01748nas a2200181   4500008004100000245008400041210006900125260001400194520113500208100002501343700002301368700003101391700002901422700002501451700002801476700002501504856003701529       2023                        eng d00aThermally driven quantum refrigerator autonomously resets superconducting qubit0 aThermally driven quantum refrigerator autonomously resets superc  c5/26/20233 a<p>The first thermal machines steered the industrial revolution, but their quantum analogs have yet to prove useful. Here, we demonstrate a useful quantum absorption refrigerator formed from superconducting circuits. We use it to reset a transmon qubit to a temperature lower than that achievable with any one available bath. The process is driven by a thermal gradient and is autonomous -- requires no external control. The refrigerator exploits an engineered three-body interaction between the target qubit and two auxiliary qudits coupled to thermal environments. The environments consist of microwave waveguides populated with synthesized thermal photons. The target qubit, if initially fully excited, reaches a steady-state excited-level population of 5&times;10&minus;4&plusmn;5&times;10&minus;4 (an effective temperature of 23.5~mK) in about 1.6~μs. Our results epitomize how quantum thermal machines can be leveraged for quantum information-processing tasks. They also initiate a path toward experimental studies of quantum thermodynamics with superconducting circuits coupled to propagating thermal microwave fields.</p>1 aAamir, Mohammed, Ali1 aSuria, Paul, Jamet1 aGuzmán, José, Antonio Ma1 aCastillo-Moreno, Claudia1 aEpstein, Jeffrey, M.1 aHalpern, Nicole, Yunger1 aGasparinetti, Simone  uhttps://arxiv.org/abs/2305.16710