A natural atom placed into a cavity with time-dependent parameters can beparametrically excited due to the interaction with the quantized photon mode.One of the channels of such a process is the dynamical Lamb effect, induced bya nonadiabatic modulation of atomic level Lamb shift. However, in experimentswith natural atoms it is quite difficult to isolate this effect from othermechanisms of atom excitation. We point out that a transmission line cavitycoupled with a superconducting qubit (artificial macroscopic atom) provides aunique platform for the observation of the dynamical Lamb effect. A key idea isto exploit a dynamically tunable qubit-resonator coupling, which wasimplemented quite recently. By varying nonadiabatically the coupling, it ispossible to parametrically excite a qubit through a nonadiabatic modulation ofthe Lamb shift, even if the cavity was initially empty. A dynamics of such acoupled system is studied within the Rabi model with time-dependent couplingconstant and beyond the rotating wave approximation. An efficient method toincrease the effect through the periodic and nonadiabatic switching of aqubit-resonator coupling energy is proposed.
展开▼
