{"title":"Information capacity of a single photon","authors":"P. Rohde, J. Fitzsimons, A. Gilchrist","doi":"10.1103/PhysRevA.88.022310","DOIUrl":null,"url":null,"abstract":"Quantum states of light are the obvious choice for communicating quantum information. To date, encoding information into the polarization states of single photons has been widely used as these states form a natural closed two-state qubit. However, photons are able to encode much more\\char22{}in principle, infinite\\char22{}information via the continuous spatiotemporal degrees of freedom. Here we consider the information capacity of an optical quantum channel, such as an optical fiber, where a spectrally encoded single photon is the means of communication. We use the Holevo bound to calculate an upper bound on the channel capacity, and relate this to the spectral encoding basis and the spectral properties of the channel. Further, we derive analytic bounds on the capacity of such channels, and, in the case of a symmetric two-state encoding, calculate the exact capacity of the corresponding channel.","PeriodicalId":48702,"journal":{"name":"Physical Review a","volume":"88 1","pages":"022310"},"PeriodicalIF":2.9000,"publicationDate":"2012-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1103/PhysRevA.88.022310","citationCount":"9","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Review a","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1103/PhysRevA.88.022310","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"OPTICS","Score":null,"Total":0}
引用次数: 9
Abstract
Quantum states of light are the obvious choice for communicating quantum information. To date, encoding information into the polarization states of single photons has been widely used as these states form a natural closed two-state qubit. However, photons are able to encode much more\char22{}in principle, infinite\char22{}information via the continuous spatiotemporal degrees of freedom. Here we consider the information capacity of an optical quantum channel, such as an optical fiber, where a spectrally encoded single photon is the means of communication. We use the Holevo bound to calculate an upper bound on the channel capacity, and relate this to the spectral encoding basis and the spectral properties of the channel. Further, we derive analytic bounds on the capacity of such channels, and, in the case of a symmetric two-state encoding, calculate the exact capacity of the corresponding channel.
期刊介绍:
Physical Review A (PRA) publishes important developments in the rapidly evolving areas of atomic, molecular, and optical (AMO) physics, quantum information, and related fundamental concepts.
PRA covers atomic, molecular, and optical physics, foundations of quantum mechanics, and quantum information, including:
-Fundamental concepts
-Quantum information
-Atomic and molecular structure and dynamics; high-precision measurement
-Atomic and molecular collisions and interactions
-Atomic and molecular processes in external fields, including interactions with strong fields and short pulses
-Matter waves and collective properties of cold atoms and molecules
-Quantum optics, physics of lasers, nonlinear optics, and classical optics