Thermally driven quantum refrigerator autonomously resets a superconducting qubit

Abstract Although classical thermal machines power industries and modern living, quantum thermal engines have yet to prove their utility. Here, we demonstrate a useful quantum absorption refrigerator formed from superconducting circuits. We use it to cool a transmon qubit to a temperature lower than that achievable with any one available bath, thereby resetting the qubit to an initial state suitable for quantum computing. The process is driven by a thermal gradient and is autonomous, requiring no external feedback. The refrigerator exploits an engineered three-body interaction between the target qubit and two auxiliary qudits. Each auxiliary qudit is coupled to a physical heat bath, realized with a microwave…

• NS
  National Science Foundation

  Awards: 2120757, OMA-2120757, 1748958
• JT
  John Templeton Foundation

  Award: 62422
• EC
  European Commission

  Awards: 101041744, 101080167
• CT
  Chalmers Tekniska Högskola
• KO
  Knut och Alice Wallenbergs Stiftelse
• V
  Vetenskapsrådet
• NI
  National Institute of Standards and Technology

  Award: OMA-2120757
• WC
  Wallenberg Center for Quantum Technology, Chalmers University of Technology