By Cnr Ifn
We are developing flux-pumped Josephson Parametric Amplifiers (JPA), composed of coplanar resonators terminated by a double junction SQUID. We are interested in these devices because of their unique potential as ultralow noise amplifiers of microwave signals, capable of approaching the standard quantum limit (SQL) or even overcoming the SQL when operated in the degenerate phase-sensitive mode. Quantum limited amplification of microwave signals is needed in circuit-QED systems and quantum computing, but is also relevant in fundamental physics, for instance in the detection of axionlike dark matter. On a more fundamental level, the flux-pumped JPA is a paradigmatic system which allows one to observe the so-called Dynamical Casimir Effect (DCE), i.e. the generation of pairs of entangled photons out of the quantum vacuum. We aim at observing the DCE and characterizing some of its remarkable properties, including dissipative effects.
