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...
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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 Capacities of Channels with small Environment
We investigate the quantum capacity of noisy quantum channels which can be represented by coupling a system to an effectively small environment. A capacity formula is derived for all cases where both system and environment are two-dimensional—including all extremal qubit channels. Similarly, for channels acting on higher dimensional systems we show that the capacity can be determined if the cha...
متن کاملEnergy-constrained private and quantum capacities of quantum channels
This paper establishes a general theory of energy-constrained quantum and private capacities of quantum channels. We begin by defining various energy-constrained communication tasks, including quantum communication with a uniform energy constraint, entanglement transmission with an average energy constraint, private communication with a uniform energy constraint, and secret key transmission wit...
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ژورنال
عنوان ژورنال: Physical Review Letters
سال: 1997
ISSN: 0031-9007,1079-7114
DOI: 10.1103/physrevlett.78.3217