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  • Open Access

Continuous-variable quantum key distribution with a single quadrature measurement at an arbitrary reference frame

Vinod N. Rao1,2,*, Emma Tien Hwai Medlock1, Timothy Spiller1,2, and Rupesh Kumar1,2,†

  • 1School of Physics, Engineering & Technology and York Centre for Quantum Technologies, University of York, YO10 5FT York, United Kingdom
  • 2Quantum Communications Hub, University of York, United Kingdom

  • *Contact author: vinod.rao@york.ac.uk
  • †Contact author: rupesh.kumar@york.ac.uk
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Phys. Rev. A 112, 042406 – Published 3 October, 2025

DOI: https://doi.org/10.1103/g465-pm47

Abstract

We propose a simplified measurement scheme for a Gaussian modulated coherent state (GMCS) protocol for continuous variable quantum key distribution (CV-QKD), utilizing homodyne detection without quadrature switching. The reference frame of measurement is taken to be at an arbitrary angle, however, reconciliation converges the proposed scheme to GMCS with switching quadrature protocol. The arbitrary frame of measurement could also include the unknown random thermal drift within Bob's optical measurement setup. We found this scheme is advantageous for practical free-space and fiber-based GMCS protocol-based CV-QKD systems as it does not require a phase modulator for random measurement selection quadrature at Bob.

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Outline

Information

Phys. Rev. A 112, 042406– Published 3 October, 2025
  • Received 27 May 2025
  • Revised 5 September 2025
  • Accepted 15 September 2025
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