Spectral function and fidelity susceptibility in quantum critical phenomena
Department of Physics and ITP, The Chinese University of Hong Kong - Hong Kong, China
Received: 12 August 2014
Accepted: 24 September 2014
In this paper, we derive a simple equality that relates the spectral function and the fidelity susceptibility , i.e. with η being the half-width of the resonance peak in the spectral function. Since the spectral function can be measured in experiments by the neutron scattering or the angle-resolved photoemission spectroscopy (ARPES) technique, our equality makes the fidelity susceptibility directly measurable in experiments. Physically, our equality reveals also that the resonance peak in the spectral function actually denotes a quantum criticality-like point at which the solid state seemly undergoes a significant change.
PACS: 05.30.Rt – Quantum phase transitions / 75.40.Gb – Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.) / 64.60.-i – General studies of phase transitions
© EPLA, 2014