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arXiv · 2007.03897

Quantum capacity of bosonic dephasing channel

Amir Arqand·Laleh Memarzadeh·Stefano Mancini
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Abstract

We study the quantum capacity of continuous variable dephasing channel, which is a notable example of non-Gaussian quantum channel. We prove that a single letter formula applies. We then consider input energy restriction and show that by increasing it, the capacity saturates to a finite value. The optimal input state is found to be diagonal in the Fock basis and with a distribution that is a discrete version of a Gaussian. Relations between its mean/variance and dephasing rate/input energy are put forward. We also show that quantum capacity decays exponentially for large values of dephasing rates.

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Amir Arqand, Laleh Memarzadeh, Stefano Mancini. 2020-07-08. Quantum capacity of bosonic dephasing channel. https://doi.org/10.1103/physreva.102.042413

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