Paolo Solinas

A Microwave Josephson Refrigerator

  1. Paolo Solinas,
  2. Riccardo Bosisio,
  3. and Francesco Giazotto
We present a microwave quantum refrigeration principle based on the Josephson effect. When a superconducting quantum interference device (SQUID) is pierced by a time-dependent magnetic
flux, it induces changes in the macroscopic quantum phase and an effective finite bias voltage appears across the SQUID. This voltage can be used to actively cool well below the lattice temperature one of the superconducting electrodes forming the interferometer. The achievable cooling performance combined with the simplicity and scalability intrinsic to the structure pave the way to a number of applications in quantum technology.
arxiv pdf

Lamb shift enhancement and detection in strongly driven superconducting circuits

  1. Vera Gramich,
  2. Simone Gasparinetti,
  3. Paolo Solinas,
  4. and Joachim Ankerhold
It is shown that strong driving of a quantum system substantially enhances the Lamb shift induced by broadband reservoirs which are typical for solid-state devices. By varying drive
parameters the impact of environmental vacuum fluctuations with continuous spectral distribution onto system observables can be tuned in a distinctive way. This provides experimentally feasible measurement schemes for the Lamb shift in superconducting circuits based on Cooper pair boxes, where it can be detected either in shifted dressed transition frequencies or in pumped charge currents.
arxiv pdf