Random Sampling of Quantum States: a Survey of Methods And Some Issues Regarding the Overparametrized Method



Título del documento: Random Sampling of Quantum States: a Survey of Methods And Some Issues Regarding the Overparametrized Method
Revue: Brazilian journal of physics
Base de datos: PERIÓDICA
Número de sistema: 000389441
ISSN: 0103-9733
Autores: 1
Instituciones: 1Universidade Federal de Santa Maria, Centro de Ciencias Naturais e Exatas, Santa Maria, Rio Grande do Sul. Brasil
Año:
Periodo: Dic
Volumen: 45
Número: 6
Paginación: 575-583
País: Brasil
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Experimental, aplicado
Resumen en inglés The numerical generation of random quantum states (RQS) is an important procedure for investigations in quantum information science. Here, we review some methods that may be used for performing that task. We start by presenting a simple procedure for generating random state vectors, for which the main tool is the random sampling of unbiased discrete probability distributions (DPD). Afterwards, the creation of random density matrices is addressed. In this context, we first present the standard method, which consists in using the spectral decomposition of a quantum state for getting RQS from random DPDs and random unitary matrices. In the sequence, the Bloch vector parametrization method is described. This approach, despite being useful in several instances, is not in general convenient for RQS generation. In the last part of the article, we regard the overparametrized method (OPM) and the related Ginibre and Bures techniques. The OPM can be used to create random positive semidefinite matrices with unit trace from randomly produced general complex matrices in a simple way that is friendly for numerical implementations. We consider a physically relevant issue related to the possible domains that may be used for the real and imaginary parts of the elements of such general complex matrices. Subsequently, a too fast concentration of measure in the quantum state space that appears in this parametrization is noticed
Disciplinas: Física y astronomía
Palabras clave: Física atómica y molecular,
Estados cuánticos aleatorios,
Generación numérica,
Método de sobreparametrización
Keyword: Physics and astronomy,
Atomic and molecular physics,
Random quantum states,
Numerical generation,
Overparametrized method
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