Fidelity spectrum and phase transitions of quantum systems

P. D. Sacramento, N. Paunkovic, V. R. Vieira

Quantum fidelity between two density matrices, $F({\rho }_1,{\rho }_2)$ is usually defined as the trace of the operator $\mathcal{F}=\sqrt{\sqrt{{\rho }_1}{\rho }_2\sqrt{{\rho }_1}}$. We study the logarithmic sp…