arXiv:1010.1048 · Physical Review Letters
Quantum Fidelity in the Thermodynamic Limit
Marek M. Rams, Bogdan Damski
Abstract
We study quantum fidelity, the overlap between two ground states of a many-body system, focusing on the thermodynamic regime. We show how a drop in fidelity near a critical point encodes universal information about a quantum phase transition. Our general scaling results are illustrated in the quantum Ising chain for which a remarkably simple expression for fidelity is found.