1202.1495 (Ferdi Altintas et al.)

Correlation and nonlocality measures as indicators of quantum phase
transitions in several critical systems    [PDF]

Ferdi Altintas, Resul Eryigit

We have investigated the quantum phase transitions in the ground states of
several critical systems, including transverse field Ising and XY models as
well as XY with multiple spin interactions, XXZ and the collective system LMG
models, by using different quantumness measures, such as entanglement of
formation, quantum discord, as well as its classical counterpart,
measurement-induced disturbance and CHSH-Bell function. We have searched for
quantum information theory based new indicators of the critical points of phase
transitions in these critical systems, such as measurement-induced disturbance
and CHSH function, and have compared and contrasted them with the well known
critical point detectors, the so-called, quantum discord, entanglement and
classical correlations. Measurement-induced disturbance is found to detect the
first and second order phase transitions present in these critical systems,
while, surprisingly, it is found to fail to signal the infinite-order phase
transition present in XXZ model. Remarkably, CHSH-Bell function, although is
not violated, is found to detect all the phase transitions, even when quantum
and classical correlations are zero for the relevant ground state.

View original: http://arxiv.org/abs/1202.1495