CV-QKD with Gaussian and Non-Gaussian Entangled States over Satellite-Based Channels

Abstract

In this work we investigate the effectiveness of continuous-variable (CV) entangled states, transferred through high-loss atmospheric channels, as a means of viable quantum key distribution (QKD) between terrestrial stations and low-Earth orbit (LEO) satellites. In particular, we investigate the role played by the Gaussian CV states as compared to non-Gaussian states. We find that beam-wandering induced atmospheric losses lead to QKD performance levels that are in general quite different from those found in fixed-attenuation channels. For example, circumstances can be found where no QKD is viable at some fixed loss in fiber but is viable at the same mean loss in fading channels. We also find that, in some circumstances, the QKD relative performance of Gaussian and non-Gaussian states can in atmospheric channels be the reverse of that found in fixedattenuation channels. These findings show that the nature of the atmospheric channel can have a large impact on the QKD performance. Our results should prove useful for emerging global quantum communications that use LEO satellites as communication relays.

Photonic Engineering for CV-QKD Over Earth-Satellite Channels

“…After receiving a mode, Bob will perform an imperfect homodyne detection with a detection thermal noise ν and an efficiency η d . This imperfection can be modeled by first interacting mode B 2 with one mode of a TMSV state (G 0 −H) with variance ν at a beam splitter with transmissivity η d [31]. Denoting G and B 3 as the output modes of such a beam splitter, mode B 3 will then be injected into a perfect homodyne detector.…”

Quantum Communications via Satellite with Photon Subtraction

“…Using the Fock basis, Alice's initial TMSV state |ψ AB0 has the form 3 We note that a PS at the transmitter in the context of a somewhat different QKD protocol from that studied here has been investigated for the Earthsatellite channel [28]. 4 A collective attack is where Eve creates a series of ancillary modes with a member from this series independently entangling with each incoming mode sent by Alice.…”

Satellite-Based Continuous-Variable Quantum Communications: State-of-the-Art and a Predictive Outlook

“…The entanglement properties of quantum states in the turbulent atmosphere have also been studied in [86], [87]. Satellite-based CV quantum communication in the context of Gaussian and non-Gaussian entanglement distribution, and its application to CV-QKD, have been investigated in detail in [88]- [92]. The results presented in [88]- [92] apply for both a single point-to-point atmospheric channel, and in combined satellite-based atmospheric channels where the satellite acts as a relay.…”

“…3, Alice and Bob are able to invoke CV-QKD protocols in the EB scheme by applying homodyne or heterodyne detection of their own modes. The level of entanglement produced by the quantum communication schemes considered here as well as the quantum key rates of the EB CV-QKD protocols in these schemes have recently been analyzed in [88]- [92].…”