Stabilizing two-qubit remote entanglement with engineered synthetic squeezing*

It is well known that qubits immersed in a squeezed vacuum environment exhibit many exotic phenomena, including dissipative entanglement stabilization. Here, we show that these effects only require interference between excitation and decay processes, and can be faithfully realized without using non-classical light; instead, one uses simple classical temporal modulation. We present and analyze two schemes that harnesses this idea to stabilize entanglement between two remote qubits coupled via a transmission line or waveguide, where either the qubit-waveguide coupling is modulated, or the qubits are directly driven. Our protocols are especially well suited to state of the art circuit cavity QED systems featuring tuneable coupling elements (e.g. Ref. [1]), as well as more general circuit waveguide QED systems (e.g Ref. [2]).

[1] H.-S. Chang et al, Phys. Rev. Lett. 124, 240502 (2020).

[2] M. Mirhosseini, M., et al, Nat. Commun. 9, 3706 (2018)