Improved lower bound for the two-way-assisted quantum capacity of the bosonic thermal-loss channel

Abstract:The bosonic thermal-loss channel is a fundamental model for quantum communication. This Gaussian channel models the transmission of bosonic systems subject to both loss and thermal noise. It describes many practical systems, including optical fibers, waveguides and free-space links, where background thermal noise is significant. Determining the channel's two-way-assisted quantum capacity, the maximum rate at which quantum information can be transmitted reliably through the channel with two-way classical assistance, remains an open problem. Here, we improve upon the best known lower bound for this capacity for a wide range of channel parameters. We achieve this by combining an improved qubit-bosonic distribution technique with a recently introduced technique for discovering entanglement distillation protocols.

REVTeX. 7 pages. 4 figures

Quantum Physics (quant-ph); Mathematical Physics (math-ph); Computational Physics (physics.comp-ph); Optics (physics.optics)

arXiv:2609.27792 [quant-ph]

(or arXiv:2609.27792v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2609.27792 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website.

Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them.

Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs.