We investigate the continuous-variable entanglement swapping protocol in a non-Gaussian setting, with non-Gaussian states employed either as entangled inputs and/or as swapping resources. The quality of the swapping protocol is assessed in terms of the teleportation fidelity achievable when using the swapped states as shared entangled resources in a teleportation protocol. We thus introduce a two-step cascaded quantum communication scheme that includes a swapping protocol followed by a teleportation protocol. The swapping protocol is fed by a general class of tunable non-Gaussian states, the Squeezed Bell states, which, by means of controllable free parameters, allows to pass in a continuous way from Gaussian twin beams up to maximally non-Gaussian squeezed number states. In the realistic instance, taking into account the effects of losses and imperfections, we show that as the input two-mode squeezing increases, optimized non-Gaussian swapping resources allow for a monotonically increasing enhancement of the fidelity compared to the corresponding Gaussian setting. This result suggests that the use of non-Gaussian resources can be useful to guarantee the success of continuous-variable entanglement swapping in the presence of decoherence.
Non-Gaussian swapping of entangled resources
DELL'ANNO, Fabio;BUONO, DANIELA;DE SIENA, Silvio;Illuminati, Fabrizio
2019
Abstract
We investigate the continuous-variable entanglement swapping protocol in a non-Gaussian setting, with non-Gaussian states employed either as entangled inputs and/or as swapping resources. The quality of the swapping protocol is assessed in terms of the teleportation fidelity achievable when using the swapped states as shared entangled resources in a teleportation protocol. We thus introduce a two-step cascaded quantum communication scheme that includes a swapping protocol followed by a teleportation protocol. The swapping protocol is fed by a general class of tunable non-Gaussian states, the Squeezed Bell states, which, by means of controllable free parameters, allows to pass in a continuous way from Gaussian twin beams up to maximally non-Gaussian squeezed number states. In the realistic instance, taking into account the effects of losses and imperfections, we show that as the input two-mode squeezing increases, optimized non-Gaussian swapping resources allow for a monotonically increasing enhancement of the fidelity compared to the corresponding Gaussian setting. This result suggests that the use of non-Gaussian resources can be useful to guarantee the success of continuous-variable entanglement swapping in the presence of decoherence.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.