Lower and upper bounds on the fidelity susceptibility

Abstract

We derive upper and lower bounds on the fidelity susceptibility in terms of macroscopic thermodynamical quantities, like susceptibilities and thermal average values. The quality of the bounds is checked by the exact expressions for a single spin in an external magnetic field. Their usefulness is illustrated by two examples of many-particle models which are exactly solved in the thermodynamic limit: the Dicke superradiance model and the single impurity Kondo model. It is shown that as far as divergent behavior is considered, the fidelity susceptibility and the thermodynamic susceptibility are equivalent for a large class of models exhibiting critical behavior.

19 pages

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Cited by in corpus (4)

• Finite-temperature fidelity and von Neumann entropy in the honeycomb spin lattice with quantum Ising interaction
• Mixed-state fidelity susceptibility through iterated commutator series expansion
• Monotone Riemannian metrics and dynamic structure factor in condensed matter physics
• Some inequalities in the fidelity approach to phase transitions