Quantum Decay for Common Quantum States

A.P. Grécos

Zhihai Wang, Dong Zhou

Within the capacity of current experiments, we design a composite atom-cavity system with a common bath, in which the decay channels of the atom and the cavity mode interfere with each other. When the direct atom-cavity coupling is absent, the system can be trapped in a quasidark state (the coherent superposition of excited states for the atom and the cavity mode) without decay even in the presence of the bath. When the atom directly couples with the cavity, the largest decay rate of the composite system will surpass the sum of the two subsystems while the smallest decay rate may achieve 0. This is manifested in the transmission spectrum, where the vacuum Rabi splitting shows an obvious asymmetric character.

E. Torrontegui, Juan Gonzalo Muga, Joan Martorell +1 more

Offek Tziperman, Ron Ruimy, Alexey A. Gorlach +1 more

We propose a protocol to create entanglement between emitters in cavity- or waveguide-QED through their decay to a common channel. Heralding on emitters’ states creates desired quantum light states such as cat and GKP.

Francesco Giacosa

In the study of decays, it is quite common that an unstable quantum state/particle has multiple distinct decay channels.In this case, besides the survival probability p(t), also the probability wi(t) that a decay occurs between (0, t) in the i-th channel is a relevant object.The general form of the function wi(t) was recently presented in PLB 831, 137200 (2022).Here, we provide a novel and detailed "joint" derivation of both p(t) and wi(t).As it is well known, p(t) is not an exponential function; similarly, wi(t) is not one either.In particular, the ratio wi/wj (for i = j) is not a simple constant as it would be in the exponential limit.The functions wi(t) and their mutual ratios may therefore represent a novel tool to study the non-exponential nature of the decay law.