6533b837fe1ef96bd12a2919

RESEARCH PRODUCT

Scaling of Berry's phase close to the Dicke quantum phase transition

Francesco PlastinaGiuseppe LibertiAngelo Carollo

subject

Quantum phase transitionPhysicsQuantum PhysicsPhase transitionFOS: Physical sciencesGeneral Physics and AstronomyGeometric phaseCritical point (thermodynamics)Quantum mechanicsQubitThermodynamic limitQuantum phase transition Berry phaseQuantum Physics (quant-ph)Adiabatic processCritical exponent

description

We discuss the thermodynamic and finite size scaling properties of the geometric phase in the adiabatic Dicke model, describing the super-radiant phase transition for an $N$ qubit register coupled to a slow oscillator mode. We show that, in the thermodynamic limit, a non zero Berry phase is obtained only if a path in parameter space is followed that encircles the critical point. Furthermore, we investigate the precursors of this critical behavior for a system with finite size and obtain the leading order in the 1/N expansion of the Berry phase and its critical exponent.

https://doi.org/10.1209/epl/i2006-10270-x