Long-distance free-space quantum key distribution with continuous variables
arXiv:2507.21546 · doi:10.1103/hvhx-pdrn
Abstract
Continuous-variable quantum key distribution (CVQKD) enables remote users to share high-rate and unconditionally secure secret keys while maintaining compatibility with classical optical communication networks and effective resistance against background noise. However, CVQKD experiments have only been demonstrated indoors or over short outdoor distances. Here, by developing channel-fluctuation-independent high-precision manipulation of continuous-variable quantum states, high-accuracy quantum signal acquisition and processing, and high-efficiency free-space acquisition, tracking, and pointing technology, we overcome the excess noise due to atmospheric effects especially in daylight without extra wavelength conversion and spectral filtering, and demonstrate for the first time long-distance free-space quantum key distribution over 7-km inland and 9.6-km maritime atmospheric channels with Gaussian-modulated coherent states. This achieved distribution distance of secure quantum secret keys is well beyond the atmosphere's effective thickness, offering a promising alternative for realizing satellite-based quantum cryptography communication in daylight. Moreover, given that the CVQKD system is naturally compatible with existing ground fiber telecommunication networks, it marks an essential step for realizing integrated air-ground quantum access networks with cross-domain applications.
References in corpus (36)
- Gaussian Quantum Information
- Advances in Quantum Cryptography
- Continuous variable quantum cryptography using coherent states
- Quantum key distribution using gaussian-modulated coherent states
- Fundamental Limits of Repeaterless Quantum Communications
- General Benchmarks for Quantum Repeaters
- Distillation of secret key and entanglement from quantum states
- Experimental demonstration of long-distance continuous-variable quantum key distribution
- Optimality of Gaussian Attacks in Continuous Variable Quantum Cryptography
- Finite-size analysis of continuous-variable quantum key distribution
- Long-Distance Continuous-Variable Quantum Key Distribution over 202.81 km of Fiber
- Unconditional security proof of long-distance continuous-variable quantum key distribution with discrete modulation
- Composable security proof for continuous-variable quantum key distribution with coherent states
- A de Finetti representation theorem for infinite dimensional quantum systems and applications to quantum cryptography
- Continuous-Variable Quantum Key Distribution with Gaussian Modulation -- The Theory of Practical Implementations
- Long Distance Continuous-Variable Quantum Key Distribution with a Gaussian Modulation
- Continuous Variable Quantum Cryptography using Two-Way Quantum Communication
- Security of continuous-variable quantum key distribution via a Gaussian de Finetti reduction
- Security of continuous-variable quantum key distribution against general attacks
- Multidimensional reconciliation for continuous-variable quantum key distribution
- Toward Global Quantum Communication: Beam Wandering Preserves Nonclassicality
- Continuous-variable quantum key distribution system: past, present, and future
- Satellite-Based Continuous-Variable Quantum Communications: State-of-the-Art and a Predictive Outlook
- Self-coherent phase reference sharing for continuous-variable quantum key distribution
- Entanglement of Gaussian states and the applicability to quantum key distribution over fading channels
- Feasibility of satellite-to-ground continuous-variable quantum key distribution
- Asymptotic security of continuous-variable quantum key distribution with a discrete modulation
- Continuous-variable measurement-device-independent quantum key distribution: Composable security against coherent attacks
- Feasibility of free space quantum key distribution with coherent polarization states
- Atmospheric effects on continuous-variable quantum key distribution
- Finite-size security of continuous-variable quantum key distribution with digital signal processing
- Continuous-variable quantum key distribution in fast fading channels
- Finite-Size Security for Discrete-Modulated Continuous-Variable Quantum Key Distribution Protocols
- Fading channel estimation for free-space continuous-variable secure quantum communication
- Free-space continuous-variable quantum key distribution of unidimensional Gaussian modulation using polarized coherent-states in urban environment
- Homodyne detection for atmosphere channels