Gaussian entanglement distribution via satellite

Abstract

In this work we analyze three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme, the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the tradeoff between space-based engineering complexity and the rate of ground-station entanglement generation.

Photonic Engineering for CV-QKD Over Earth-Satellite Channels

“…We study only non-Gaussian operations at the transmitter side. 2 We consider two schemes, namely the T-PS and the T-PA schemes. As illustrated in Fig.…”

Quantum Communications via Satellite with Photon Subtraction

“…We also find the T-PS and R-PS schemes can outperform the No-PS scheme in some parameter space (again we caution that optimisation of the initial squeezing can alter these conclusions). We next investigate the key rates of the three schemes in the variable Earth-satellite channel, calculating their average key rates under different average channel fluctuations, quantified using σ b within equations (1)- (2). These results are shown in Fig.…”

Continuous-variable quantum key distribution in uniform fast-fading channels

“…In this case, the transmissivity η of the link between the two parties is not constant and may take values according to some probability distribution [43]. This description usually emerges from the fact that the parties use a free-space link [44] that is susceptible to the atmospheric turbulence [45][46][47][48][49][50][51]. Previous studies (e.g., see Ref.…”

“…Previous studies (e.g., see Ref. [52]) have considered the symmetric situation where both users and eavesdropper are subject to truly environmental fading. In this manuscript, we consider a different situation, i.e., the worst-case scenario where the eavesdropper is in complete control of the quantum channel, so that she may choose different instantaneous values of the transmissivity for each use of the channel.…”