Stefano Pirandola

Improved two-way capacity upper bounds for amplitude-damping channels

Abstract: We derive an improved upper bound on the two-way-assisted capacities of the qubit amplitude-damping channel with decay probability $\gamma$, given by $\log_2[1+(1-\gamma)\gamma^{\gamma/(1-\gamma)}]$. It applies to quantum communication, entanglement distribution, privat...

Stability of energy-constrained bosonic capacities under extensions of LOCC

Abstract: The energy-constrained two-way capacities of pure-loss and quantum-limited amplifier channels have been determined in a combined treatment using finite-round local operations and classical communication with finite or countable outcomes. We prove that the same vanishing...

Exact series formulas for the capacities of the amplitude damping channel

Abstract: We derive explicit, absolutely convergent series formulas for the quantum, unassisted classical, and entanglement-assisted classical capacities of the qubit amplitude damping channel, eliminating residual optimizations and implicit roots. We also obtain analytical upper...

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

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 lin...