The effect of classical driving field on the spectrum of a qubit and entanglement swapping inside dissipative cavities

Abstract

In this paper, we study the effect of classical driving field on the spontaneous emission spectrum of a qubit embedded in a dissipative cavity. Furthermore, we monitor the entanglement dynamics of the driven qubit with its radiative decay under the action of the classical field. Afterwards, we carry out an investigation on the possibility of entanglement swapping between two such distinct driven qubits. The swapping will be feasible with the aid of a Bell state measurement performing on the photons leaving the cavities. It is demonstrated that the classical driving field has a beneficial effect on the prolonging of the swapped entanglement.

Entanglement protection of classically driven qubits in a lossy cavity

“…Here ( ) represents the new lowering (raising) operator. It should be noted that during the derivation of the effective Hamiltonian ( 4 ), the non-conservation energy terms have been neglected according to the rotating-wave approximation 25 , 26 . It should be noted that the counter-rotating terms arising from the unitary transformation have been neglected.…”

Multistage entanglement swapping using superconducting qubits in the absence and presence of dissipative environment without Bell state measurement

“…At last, due to the importance of calculating the fidelity of the produced or distributed entangled states in entanglement swapping protocols, this measure was considered to study the closeness of the achieved entangled states for qubits (1,4), (1,8) to the initial Bell state (1). As shown in figure 10, the convincing amount of fidelity was achieved for the produced entangled states.…”

“…The performance of the storage and retrieval of quantum memories is improved using SC quantum processors and solid-state quantum memories [43]. The above-mentioned advantages and interesting properties of SC motivated us to consider distribution of entangled states of target SC qubits (1,8) among SC qubits (1, 2, • • • , 8) which are aligned as in figure 1. The SC pairs (i, i + 1) where i = 1, 3, 5, 7 are initially prepared in maximally entangled states [44,45].…”

“…The entangled states for SC qubits (1,4) and (5,8) are achieved by implementing external magnetic fields on capacitively coupled pairs (2, 3) and (6, 7) followed by operating proper measurements. Then, the distributed entangled state of target SC qubits (1,8) can be obtained by applying external magnetic fields on qubits (4,5) and operating suitable measurements. To study entanglement swapping protocol in real conditions the effect of dissipation is also considered via the thermal noise influences.…”

Entanglement Protection of Classically Driven Qubits in a Lossy Cavity

“…Here ̺( j) + = |E j G| ( ̺( j) − = |G j E|) represents the new lowering (raising) operator. It should be noted that during the derivation of the effective Hamiltonian (4), the non-conservation energy terms have been neglected according to the rotatingwave approximation 26,27 . It should be noted that the counter-rotating terms arising from the unitary transformation have been neglected.…”