Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Circular Orbits and Critical Velocity for Satellites

Circular Orbits and Critical Velocity for Satellites

The Moon orbits around the Earth. In turn, the Earth (and other planets) orbit the Sun. The space directly above our atmosphere is filled with artificial satellites in orbit. One can examine the circular orbit, the simplest kind of orbit, to understand the relationship between the speed and the period of planets and satellites with respect to their positions and the bodies that they orbit.
Nicolaus Copernicus (1473-1543) first suggested that the Earth and all other planets orbit the Sun in...

State Space to Transfer Function

State Space to Transfer Function

The conversion of state-space representation to a transfer function is a fundamental process in system analysis. It provides a method for transitioning from a time-domain description to a frequency-domain representation, which is crucial for simplifying the analysis and design of control systems.
The transformation process begins with the state-space representation, characterized by the state equation and the output equation. These equations are typically represented as:

Energy of a Satellite in a Circular Orbit

Energy of a Satellite in a Circular Orbit

Thousands of artificial satellites orbit the Earth every day at various distances from the Earth. Satellites that orbit the Earth below an altitude of 1,600 km are considered to be orbiting in low-Earth orbit (LEO). Research satellites and Earth observation satellites are usually placed in LEO, and mostly orbit the Earth in elliptical orbits. Navigation satellites are placed in medium-Earth orbit (MEO), ranging from 2,000 km to 36,000 km from the surface of the Earth. Meanwhile, communication...

Energy Stored In A Coaxial Cable

Energy Stored In A Coaxial Cable

A coaxial cable consists of a central copper conductor used for transmitting signals, followed by an insulator shield, a metallic braided mesh that prevents signal interference, and a plastic layer that encases the entire assembly.
In the simplest form, a coaxial cable can be represented by two long hollow concentric cylinders in which the current flows in opposite directions. The magnetic field inside and outside the coaxial cable is determined by using Ampère's law. The magnetic field inside...

BIBO stability of continuous and discrete -time systems

BIBO stability of continuous and discrete -time systems

System stability is a fundamental concept in signal processing, often assessed using convolution. For a system to be considered bounded-input bounded-output (BIBO) stable, any bounded input signal must produce a bounded output signal. A bounded input signal is one where the modulus does not exceed a certain constant at any point in time.
To determine the BIBO stability, the convolution integral is utilized when a bounded continuous-time input is applied to a Linear Time-Invariant (LTI) system....

State Space Representation

State Space Representation

The frequency-domain technique, commonly used in analyzing and designing feedback control systems, is effective for linear, time-invariant systems. However, it falls short when dealing with nonlinear, time-varying, and multiple-input multiple-output systems. The time-domain or state-space approach addresses these limitations by utilizing state variables to construct simultaneous, first-order differential equations, known as state equations, for an nth-order system.
Consider an RLC circuit, a...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Long-distance continuous-variable quantum key distribution over 100-km fiber with local local oscillator.

Science advances·2024

Same author

Redundancy and Synergy of an Entangling Cloner in Continuous-Variable Quantum Communication.

Entropy (Basel, Switzerland)·2023

See all related articles

Search research articles

Related Experiment Video

Updated: Nov 23, 2025

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Published on: May 30, 2014

Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links.

Ivan Derkach¹, Vladyslav C Usenko¹

¹Department of Optics, Palacky University, 771 46 Olomouc, Czech Republic.

Entropy (Basel, Switzerland)

|January 5, 2021

Summary

Quantum key distribution via satellite links requires robust protocols. Optimized signal squeezing enhances security and applicability, improving satellite quantum communication over long distances.

Keywords:

coherent states continuous variables low Earth orbit quantum cryptography quantum key distribution quantum optics satellite squeezed states

More Related Videos

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

Quasi-light Storage for Optical Data Packets

Quasi-light Storage for Optical Data Packets

Published on: February 6, 2014

Related Experiment Videos

Last Updated: Nov 23, 2025

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Published on: May 30, 2014

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

Quasi-light Storage for Optical Data Packets

Quasi-light Storage for Optical Data Packets

Published on: February 6, 2014

Area of Science:

Quantum Information Science
Satellite Communication
Quantum Cryptography

Background:

Satellite-based quantum key distribution (QKD) faces challenges like channel attenuation and atmospheric turbulence.
Continuous-variable (CV) QKD protocols using coherent and squeezed states are being explored for long-distance links.

Purpose of the Study:

To assess the feasibility of CV-QKD over low Earth orbit satellite links.
To analyze the impact of channel noise, turbulence, and finite data on QKD security.
To investigate methods for enhancing the robustness and applicability of satellite QKD.

Main Methods:

Theoretical analysis of CV-QKD protocols with coherent and squeezed states.
Modeling of channel attenuation, atmospheric turbulence, and finite data effects.
Derivation of security bounds based on untrusted channel noise.
Simulation of segmented satellite passes and optimized signal squeezing.

Main Results:

Tight security bounds indicate significant noise and loss challenges for current satellite QKD setups.
Splitting satellite passes into segments improves robustness against channel noise, enabling secure keys under active collective attacks.
Optimized signal squeezing offers substantial improvements over coherent-state protocols, allowing for lower system requirements and higher noise/attenuation resilience.

Conclusions:

Satellite-based CV-QKD is challenging but feasible with optimized protocols and system stabilization.
Signal squeezing is a key technique for enhancing the practical implementation of satellite QKD.
Segmented key extraction and optimized squeezing are crucial for establishing secure satellite quantum communication networks.