Geometric phase with nonunitary evolution in presence of a quantum critical bath

Abstract

Geometric phases, arising from cyclic evolutions in a curved parameter space, appear in a wealth of physical settings. Recently, and largely motivated by the need of an experimentally realistic definition for quantum computing applications, the quantum geometric phase was generalized to open systems. The definition takes a kinematical approach, with an initial state that is evolved cyclically but coupled to an environment --- leading to a correction of the geometric phase with respect to the uncoupled case. We obtain this correction by measuring the nonunitary evolution of the reduced density matrix of a spin one-half coupled to an environment. In particular, we consider a bath that can be tuned near a quantum phase transition, and demonstrate how the criticality information imprinted in the decoherence factor translates into the geometric phase. The experiments are done with a NMR quantum simulator, in which the critical environment is modeled using a one-qubit system.

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Cited by in corpus (6)

• Geometric phase for an accelerated two-level atom and the Unruh effect
• Geometric phases in superconducting qubits beyond the two-level-approximation
• Geometric phase outside a Schwarzschild black hole and the Hawking effect
• Detecting modified vacuum fluctuations due to presence of a boundary by means of the geometric phase
• Franck-Condon Effect in Central Spin System
• Decoherence induced by an ordered environment