TY - JOUR

T1 - Connection among entanglement, mixedness and nonlocality in a dynamical context

AU - Bellomo, Bruno

AU - Compagno, Giuseppe

AU - Lo Franco, Rosario

AU - Mazzola, Laura

PY - 2010

Y1 - 2010

N2 - We investigate the dynamical relations among entanglement, mixedness, and nonlocality, quantified by concurrence C, purity P, and maximum Bell function B, respectively, in a system of two qubits in a common structured reservoir. To this aim we introduce the C-P-B parameter space and analyze the time evolution of the point representative of the system state in such a space. The dynamical interplay among entanglement, mixedness, and nonlocality strongly depends on the initial state of the system. For a two-excitation Bell state the representative point draws a multibranch curve in the C-P-B space and we show that a closed relation among these quantifiers does not hold. By extending the known relation between C and B for pure states, we give an expression among the three quantifiers for mixed states. In this equation we introduce a quantity, vanishing for pure states, which in general does not have a closed form in terms of C, P and B. Finally, we demonstrate that for an initial one-excitation Bell state, a closed C-P-B relation instead exists and the system evolves, remaining always a maximally entangled mixed state.

AB - We investigate the dynamical relations among entanglement, mixedness, and nonlocality, quantified by concurrence C, purity P, and maximum Bell function B, respectively, in a system of two qubits in a common structured reservoir. To this aim we introduce the C-P-B parameter space and analyze the time evolution of the point representative of the system state in such a space. The dynamical interplay among entanglement, mixedness, and nonlocality strongly depends on the initial state of the system. For a two-excitation Bell state the representative point draws a multibranch curve in the C-P-B space and we show that a closed relation among these quantifiers does not hold. By extending the known relation between C and B for pure states, we give an expression among the three quantifiers for mixed states. In this equation we introduce a quantity, vanishing for pure states, which in general does not have a closed form in terms of C, P and B. Finally, we demonstrate that for an initial one-excitation Bell state, a closed C-P-B relation instead exists and the system evolves, remaining always a maximally entangled mixed state.

KW - Entanglement

KW - Non-locality

KW - Open quantum systems

KW - Purity

KW - Entanglement

KW - Non-locality

KW - Open quantum systems

KW - Purity

UR - http://hdl.handle.net/10447/50870

UR - http://pra.aps.org/abstract/PRA/v81/i5/e052116

M3 - Article

VL - 2010

SP - 052116-1-052116-8

JO - PHYSICAL REVIEW A

JF - PHYSICAL REVIEW A

SN - 1050-2947

ER -