Bosonic Quantum Communication Across Arbitrarily High Loss Channels
Bosonic Quantum Communication Across Arbitrarily High Loss Channels
A general attenuator Φ_{λ,σ} is a bosonic quantum channel that acts by combining the input with a fixed environment state σ in a beam splitter of transmissivity λ. If σ is a thermal state, the resulting channel is a thermal attenuator, whose quantum capacity vanishes for λ≤1/2. We study the …