Satellite Quantum Communications: Fundamental Bounds and Practical Security
TL;DR: This work applies and extends recent results in free-space quantum communications to determine the ultimate limits at which secret bits can be distributed via satellites, and studies the composable finite-size secret key rates that are achievable by protocols of continuous variable quantum key distribution, for both downlink and uplink.
Abstract: Satellite quantum communications are emerging within the panorama of quantum technologies as a more effective strategy to distribute completely-secure keys at very long distances, therefore playing an important role in the architecture of a large-scale quantum network. In this work, we apply and extend recent results in free-space quantum communications to determine the ultimate limits at which secret (and entanglement) bits can be distributed via satellites. Our study is comprehensive of the various practical scenarios, encompassing both downlink and uplink configurations, with satellites at different altitudes and zenith angles. It includes effects of diffraction, extinction, background noise and fading, due to pointing errors and atmospheric turbulence (appropriately developed for slant distances). Besides identifying upper bounds, we also discuss lower bounds, i.e., achievable rates for key generation and entanglement distribution. In particular, we study the composable finite-size secret key rates that are achievable by protocols of continuous variable quantum key distribution, for both downlink and uplink, showing the feasibility of this approach for all configurations. Finally, we present a study with a sun-synchronous satellite, showing that its key distribution rate is able to outperform a ground chain of ideal quantum repeaters.
Citations
More filters
Journal Article•
28,685 citations
25 Mar 2021
TL;DR: This work bound the ultimate rates for key and entanglement distribution through a free-space link, where the propagation of quantum systems is generally affected by diffraction, atmospheric extinction, turbulence, pointing errors, and background noise.
Abstract: This work establishes the limits for free-space quantum communications under the effects of diffraction, atmospheric extinction, pointing error, turbulence, and background noise.
75 citations
TL;DR: In this paper , the authors reviewed the current state of the art for generating entanglement of quantum nodes based on various physical systems such as single atoms, cold atomic ensembles, trapped ions, diamonds with nitrogen-vacancy centers, and solid-state host doped with rare-earth ions.
Abstract: Quantum networks play an extremely important role in quantum information science, with application to quantum communication, computation, metrology, and fundamental tests. One of the key challenges for implementing a quantum network is to distribute entangled flying qubits to spatially separated nodes, at which quantum interfaces or transducers map the entanglement onto stationary qubits. The stationary qubits at the separated nodes constitute quantum memories realized in matter while the flying qubits constitute quantum channels realized in photons. Dedicated efforts around the world for more than 20 years have resulted in both major theoretical and experimental progress toward entangling quantum nodes and ultimately building a global quantum network. Here, the development of quantum networks and the experimental progress over the past two decades leading to the current state of the art for generating entanglement of quantum nodes based on various physical systems such as single atoms, cold atomic ensembles, trapped ions, diamonds with nitrogen‐vacancy centers, and solid‐state host doped with rare‐earth ions are reviewed. Along the way, the merits are discussed and the potential of each of these systems toward realizing a quantum network is compared.
37 citations
Posted Content•
TL;DR: This Letter describes a miniaturized, polarization entangled, photon-pair source operating on board a nano-satellite that violates Bell’s inequality with a Clauser–Horne–Shimony–Holt parameter of 2.60±0.06.
Abstract: Global quantum networks for secure communication can be realised using large fleets of satellites distributing entangled photon-pairs between ground-based nodes Because the cost of a satellite depends on its size, the smallest satellites will be most cost-effective This paper describes a miniaturised, polarization entangled, photon-pair source operating on board a nano-satellite The source violates Bell's inequality with a CHSH parameter of 26 $\pm$ 006 This source can be combined with optical link technologies to enable future quantum communication nano-satellite missions
32 citations
TL;DR: The combination of quantum physics and its space application is the focus of this review as discussed by the authors , covering both the fundamental scientific questions that can be tackled with quantum technologies in space and the possible implementation of these technologies for a variety of academic and commercial purposes.
29 citations
References
More filters
Journal Article•
28,685 citations
Book•
01 Jan 1983
TL;DR: In this paper, a Potpourri of Particles is used to describe surface modes in small Particles and the Angular Dependence of Scattering is shown to be a function of the size of the particles.
Abstract: BASIC THEORY. Electromagnetic Theory. Absorption and Scattering by an Arbitrary Particle. Absorption and Scattering by a Sphere. Particles Small Compared with the Wavelength. Rayleigh--Gans Theory. Geometrical Optics. A Potpourri of Particles. OPTICAL PROPERTIES OF BULK MATTER. Classical Theories of Optical Constants. Measured Optical Properties. OPTICAL PROPERTIES OF PARTICLES. Extinction. Surface Modes in Small Particles. Angular Dependence of Scattering. A Miscellany of Applications. Appendices. References. Index.
16,859 citations
Journal Article•
TL;DR: In this article, the authors consider the problem of finding the components of the velocity at every point of a point with rectangular cartesian coordinates x 1, x 2, x 3, x 4, x 5, x 6, x 7, x 8.
Abstract: §1. We shall denote by uα ( P ) = uα ( x 1, x 2, x 3, t ), α = 1, 2, 3, the components of velocity at the moment t at the point with rectangular cartesian coordinates x 1, x 2, x 3. In considering the turbulence it is natural to assume the components of the velocity uα ( P ) at every point P = ( x 1, x 2, x 3, t ) of the considered domain G of the four-dimensional space ( x 1, x 2, x 3, t ) are random variables in the sense of the theory of probabilities (cf. for this approach to the problem Millionshtchikov (1939) Denoting by Ᾱ the mathematical expectation of the random variable A we suppose that ῡ 2 α and (d uα /d xβ )2― are finite and bounded in every bounded subdomain of the domain G .
6,063 citations
Book•
01 Jun 1998
TL;DR: In this paper, a line-of-sight propagation of Gaussian-Beam waves in the atmosphere has been studied in the context of beam statistics mathematica programmes.
Abstract: Random Processes and Random Fields Optical Turbulence in the Atmosphere Free-Space Propagation of Gaussian-Beam Waves Classical Theory of Optical Wave Propagation Line-of-Sight Propagation - Weak Fluctuation Theory, Part 1 Line-of-Sight Propagation - Weak Fluctuation Theory, Part 2 Propagation Through Random Phase Screens Laser Satellite Communication Systems Propagation Through Complex Paraxial ABCD Optical Systems Doublepassage Problems - Laser Radar Systems Line-of-Sight Propagation - Strong Fluctuation Theory Appendices - Special Functions Integral Table Tables of Beam Statistics Mathematica Programmes.
3,633 citations
"Satellite Quantum Communications: F..." refers background in this paper
...This index is usually decomposed into a longitudinal (onaxis) and transverse (off-axis) parts [31, 57]...
[...]
...The most important of these parameters is the refraction index structure constant C(2) n [31, 47], since this is at the basis of the others and, in particular, the scintillation index [31], that characterizes the strength of turbulence, and the sphericalwave coherence length [27], that directly enters in the expressions of the spot sizes of Eq....
[...]
...In fact, recall that the number of turbulence-induced short-term speckles from a point source is of the order of Ns = 1 + (aR/ρ0) 2 [31]....
[...]