9 research outputs found
CV-QKD with Gaussian and non-Gaussian Entangled States over Satellite-based Channels
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
fixed-attenuation 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.Comment: 7 pages, 5 figure
Quantum Entanglement Distribution in Next-Generation Wireless Communication Systems
In this work we analyze the distribution of quantum entanglement over
communication channels in the millimeter-wave regime. The motivation for such a
study is the possibility for next-generation wireless networks (beyond 5G) to
accommodate such a distribution directly - without the need to integrate
additional optical communication hardware into the transceivers. Future
wireless communication systems are bound to require some level of quantum
communications capability. We find that direct quantum-entanglement
distribution in the millimeter-wave regime is indeed possible, but that its
implementation will be very demanding from both a system-design perspective and
a channel-requirement perspective.Comment: 6 pages, 4 figure
Photonic Engineering for CV-QKD over Earth-Satellite Channels
Quantum Key Distribution (QKD) via satellite offers up the possibility of
unconditionally secure communications on a global scale. Increasing the secret
key rate in such systems, via photonic engineering at the source, is a topic of
much ongoing research. In this work we investigate the use of photon-added
states and photon-subtracted states, derived from two mode squeezed vacuum
states, as examples of such photonic engineering. Specifically, we determine
which engineered-photonic state provides for better QKD performance when
implemented over channels connecting terrestrial receivers with Low-Earth-Orbit
satellites. We quantify the impact the number of photons that are added or
subtracted has, and highlight the role played by the adopted model for
atmospheric turbulence and loss on the predicted key rates. Our results are
presented in terms of the complexity of deployment used, with the simplest
deployments ignoring any estimate of the channel, and the more sophisticated
deployments involving a feedback loop that is used to optimize the key rate for
each channel estimation. The optimal quantum state is identified for each
deployment scenario investigated.Comment: Updated reference lis
Inter-satellite Quantum Key Distribution at Terahertz Frequencies
Terahertz (THz) communication is a topic of much research in the context of
high-capacity next-generation wireless networks. Quantum communication is also
a topic of intensive research, most recently in the context of space-based
deployments. In this work we explore the use of THz frequencies as a means to
achieve quantum communication within a constellation of micro-satellites in
Low-Earth-Orbit (LEO). Quantum communication between the micro-satellite
constellation and high-altitude terrestrial stations is also investigated. Our
work demonstrates that THz quantum entanglement distribution and THz quantum
key distribution are viable deployment options in the micro-satellite context.
We discuss how such deployment opens up the possibility for simpler integration
of global quantum and wireless networks. The possibility of using THz
frequencies for quantum-radar applications in the context of LEO deployments is
briefly discussed.Comment: 7 pages, 6 figure