Optimal strategies for sending information through a quantum channel
Bagán Capella, Emili (Universitat Autònoma de Barcelona. Departament de Física)
Baig i Aleu, Marià, 1955- (Universitat Autònoma de Barcelona. Departament de Física)
Brey, Antoni, 1967- (Institut de Física d'Altes Energies)
Muñoz Tapia, Ramon (Universitat Autònoma de Barcelona. Departament de Física)
Tarrach Siegel, Rolf (Universitat de Barcelona. Departament d'Estructura i Constituents de la Matèria)
American Physical Society

Date:	2000
Abstract:	Quantum states can be used to encode the information contained in a direction, i. e. , in a unit vector. We present the best encoding procedure when the quantum state is made up of N spins (qubits). We find that the quality of this optimal procedure, which we quantify in terms of the fidelity, depends solely on the dimension of the encoding space. We also investigate the use of spatial rotations on a quantum state, which provide a natural and less demanding encoding. In this case we prove that the fidelity is directly related to the largest zeros of the Legendre and Jacobi polynomials. We also discuss our results in terms of the information gain.
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; Versió publicada
Published in:	Physical review letters, Vol. 85, Issue 24 (December 2000) , p. 5230-5233, ISSN 1079-7114

DOI: 10.1103/PhysRevLett.85.5230

4 p, 87.8 KB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut de Física d’Altes Energies (IFAE)
Articles > Published articles