منابع مشابه
Quantum capacities of bosonic channels.
We investigate the capacity of bosonic quantum channels for the transmission of quantum information. We calculate the quantum capacity for a class of Gaussian channels, including channels describing optical fibers with photon losses, by proving that Gaussian encodings are optimal. For arbitrary channels we show that achievable rates can be determined from few measurable parameters by proving th...
متن کاملEvaluating capacities of bosonic Gaussian channels
We show how to compute or at least to estimate various capacity-related quantities for bosonic Gaussian channels. Among these are the coherent information, the entanglement-assisted classical capacity, the one-shot classical capacity, and a quantity involving the transpose operation, shown to be a general upper bound on the quantum capacity, even allowing for finite errors. All bounds are expli...
متن کاملCapacities of Quantum Amplifier Channels
Quantum amplifier channels are at the core of several physical processes in nature. Not only do they model the optical process of spontaneous parametric down-conversion, but the Bogoliubov transformation corresponding to an amplifier channel also describes the physics of the dynamical Casimir effect in superconducting circuits, the Unruh effect, and Hawking radiation. Here we study the communic...
متن کاملOne-Shot Quantum Capacities of Quantum Channels
We study optimal rates for quantum communication over a single use of a channel, which itself can correspond to a finite number of uses of a channel with correlated noise. The corresponding capacity is often referred to as the one-shot capacity. Here, in particular, we consider the protocol in which Alice sends one part of a maximally entangled state through a quantum channel to Bob, who then p...
متن کاملQuantum-secure covert communication on bosonic channels.
Computational encryption, information-theoretic secrecy and quantum cryptography offer progressively stronger security against unauthorized decoding of messages contained in communication transmissions. However, these approaches do not ensure stealth--that the mere presence of message-bearing transmissions be undetectable. We characterize the ultimate limit of how much data can be reliably and ...
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ژورنال
عنوان ژورنال: Physical Review Letters
سال: 2007
ISSN: 0031-9007,1079-7114
DOI: 10.1103/physrevlett.98.130501