2017/05/31 by Pietro Liuzzo-Scorpo, Andrea Mari, Vittorio Giovannetti +1 · 2 citations
Physics and Astronomy · #quant-ph #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevlett.119.120503
published as Phys. Rev. Lett. 119, 120503 (2017) · 6 pages, 1 figure; published in PRL. Update: Eq. (9) has been corrected [previously, the states of Eq. (9) were unphysical for $τ>1$]. Some statements regarding the finite-energy simulation of the quantum limited amplifier have been rectified
arxiv created 2017/11/28 · arxiv updated 2017/11/29
Given a certain amount of entanglement available as a resource, what is the most efficient way to accomplish a quantum task? We address this question in the relevant case of continuous variable quantum teleportation protocols implemented using two-mode Gaussian states with a limited degree of entanglement and energy. We first characterize the class of single-mode phase-insensitive Gaussian channels that can be simulated via a Braunstein--Kimble protocol with non-unit gain and minimum shared entanglement, showing that infinite energy is not necessary apart from the special cases of the quantum limited attenuator and amplifier. We also find that, apart from the identity, all phase-insensitive Gaussian channels can be simulated through a two-mode squeezed state with finite energy, albeit with a larger entanglement. We then consider the problem of teleporting single-mode coherent states with Gaussian-distributed displacement in phase space. Performing a geometrical optimization over phase-insensitive Gaussian channels, we determine the maximum average teleportation fidelity achievable with any finite entanglement and for any realistically finite variance of the input distribution.