Sudden change of quantum discord for a system of two qubits

Autor(es)

Pinto, Joao P. G. ^[1] ; Karpat, Goktug ^[2] ; Fanchini, Felipe F. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Ouro Preto, Dept Fis, BR-35400000 Ouro Preto, MG - Brazil

^[2] UNESP Univ Estadual Paulista, Fac Ciencias, BR-17033360 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Review A; v. 88, n. 3 SEP 30 2013.
• Citações Web of Science: 30

Resumo

It is known that quantum discord might experience a sudden transition in its dynamics when calculated for certain Bell-diagonal states (BDS) that are in interaction with their surroundings. We examine this phenomenon, known as the sudden change of quantum discord, considering the case of two qubits independently interacting with dephasing reservoirs. We first demonstrate that, for a class of initial states which can be chosen arbitrarily close to BDS, the transition is in fact not sudden, although it might numerically appear so if not studied carefully. Then, we provide an extension of this discussion covering the X-shaped density matrices. Our findings suggest that the transition of quantum discord might be sudden only for an highly idealized zero-measure subset of states within the set of all possible initial conditions of two qubits. (AU)

• Processo FAPESP: 08/57856-6 - Instituto Nacional de Ciência e Tecnologia em Informação Quântica
• Beneficiário: Amir Ordacgi Caldeira
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 12/50464-0 - Estudo das correlações quânticas em sistemas quânticos abertos
• Beneficiário: Felipe Fernandes Fanchini
• Modalidade de apoio: Auxílio à Pesquisa - Regular