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A green code attempts to minimize the total energy per-bit required to communicate across a noisy channel. The classical information-theoretic approach neglects the energy expended in processing the data at the encoder and the decoder and…

Information Theory · Computer Science 2008-05-19 Pulkit Grover , Anant Sahai

We employ quantum state discrimination theory to establish the ultimate limit for spoofing detection in electromagnetic signals encoded with random quantum states. Our analysis yields an analytical expression for the optimal bound, which we…

Noise and imperfection of realistic devices are major obstacles for implementing quantum cryptography. In particular birefringence in optical fibers leads to decoherence of qubits encoded in polarization of photon. We show how to overcome…

Quantum Physics · Physics 2009-11-10 J. -C. Boileau , R. Laflamme , M. Laforest , C. R. Myers

Nonclassical states are essential for optics-based quantum information processing, but their fragility limits their utility for practical scenarios in which loss and noise inevitably degrade, if not destroy, nonclassicality. Exploiting…

Quantum Physics · Physics 2015-03-25 Zheshen Zhang , Sara Mouradian , Franco N. C. Wong , Jeffrey H. Shapiro

Processing quantum information on continuous variables requires a highly nonlinear element in order to attain universality. Noise reduction in processing such quantum information involves the use of a nonlinear phase state as a non-Gaussian…

Quantum Physics · Physics 2019-11-27 Darren W. Moore , Andrey A. Rakhubovsky , Radim Filip

A core problem in communications is the optimal discrimination of binary-phase-shift-keyed (BPSK) signals. A longstanding goal has been to reach the fundamental quantum limit, known as the Helstrom bound, for BPSK signals encoded in…

We derive the capacity region of the Gaussian version of Willems's two-user MAC with conferencing encoders. This setting differs from the classical MAC in that, prior to each transmission block, the two transmitters can communicate with…

Information Theory · Computer Science 2008-05-06 Shraga I. Bross , Amos Lapidoth , Michele A. Wigger

We study the two-user broadcast channel with degraded message sets and derive second-order achievability rate regions. Specifically, the channel noises are not necessarily Gaussian and we use spherical codebooks for both users. The weak…

Information Theory · Computer Science 2024-10-24 Zhuangfei Wu , Lin Bai , Jinpeng Xu , Lin Zhou , Mehul Motani

We analyze the effect of phase fluctuations in an optical communication scheme based on collective detection of sequences of binary coherent state symbols using linear optics and photon counting. When the phase noise is absent, the scheme…

Multimode Gaussian quantum light, including multimode squeezed and/or multipartite quadrature entangled light, is a very general and powerful quantum resource with promising applications to quantum information processing and metrology…

Quantum Physics · Physics 2010-08-05 Olivier Pinel , Julien Fade , Nicolas Treps , Claude Fabre

Quantum communication theory focuses on the study of quantum channels for transmitting quantum information, where the transmission rate is measured by quantum channel capacity. This quantity exhibits several intriguing properties, such as…

Quantum Physics · Physics 2025-01-14 Changchun Zhong

Quantum capacity gives the fundamental limit of information transmission through a channel. However, evaluating the quantum capacities of a continuous-variable bosonic quantum channel, as well as finding an optimal code to achieve the…

Quantum Physics · Physics 2025-10-03 Adam Taylor , Michael Hanks , Hyukjoon Kwon , M. S. Kim

We consider discrete-alphabet encoding schemes for coherent-state quantum key distribution. The sender encodes the letters of a finite-size alphabet into coherent states whose amplitudes are symmetrically distributed on a circle centered in…

Quantum Physics · Physics 2018-08-02 Panagiotis Papanastasiou , Cosmo Lupo , Christian Weedbrook , Stefano Pirandola

High-dimensional entanglement has shown to have significant advantages in quantum communication. It is available in many degrees of freedom and in particular in the time-domain routinely produced in down-conversion (SPDC). While…

Quantum Physics · Physics 2024-11-22 Alexandra Bergmayr , Florian Kanitschar , Matej Pivoluska , Marcus Huber

We present a framework of a multimode dense coding network with multiple senders and a single receiver using continuous variable systems. The protocol is scalable to arbitrary numbers of modes with the encoding being displacements while the…

Quantum Physics · Physics 2022-11-29 Ayan Patra , Rivu Gupta , Saptarshi Roy , Tamoghna Das , Aditi Sen De

We present a protocol for quantum key distribution using discrete modulation of coherent states of light. Information is encoded in the variable phase of coherent states which can be chosen from a regular discrete set ranging from binary to…

Quantum Physics · Physics 2015-05-13 Denis Sych , Gerd Leuchs

The ability to efficiently realize storage and readout of optical squeezed states plays a key roll in continuous-variables quantum information processing. Here we study the quantum memory (QM) for squeezed state of propagating light in…

Quantum Physics · Physics 2014-03-18 Miao-Xin Wu , Ming-Feng Wang , Yi-Zhuang Zheng

We consider a two-user state-dependent multiaccess channel in which the states of the channel are known non-causally to one of the encoders and only strictly causally to the other encoder. Both encoders transmit a common message and, in…

Information Theory · Computer Science 2012-01-17 Abdellatif Zaidi , Pablo Piantanida , Shlomo Shamai

We show how to distribute with percentage success probabilities almost perfectly entangled qubit memory pairs over repeater channel segments of the order of the optical attenuation distance. In addition to some weak, dispersive light-matter…

Quantum Physics · Physics 2013-05-29 Ludmila Praxmeyer , Peter van Loock

Quantum information characteristics, such as quantum mutual information, loss, noise and coherent information are explicitly calculated for Bosonic attenuation/amplification channel with input Gaussian state. The coherent information is…

Quantum Physics · Physics 2007-05-23 Alexander S. Holevo