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arXiv · 1408.2199

Spectral function and fidelity susceptibility in quantum critical phenomena

Shi-Jian Gu·Wing Chi Yu
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Abstract

In this paper, we derive a simple equality that relates the spectral function $I(k,ω)$ and the fidelity susceptibility $χ_F$, i.e. $% χ_F=\lim_{η\rightarrow 0}\fracπη I(0, iη)$ 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.

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Shi-Jian Gu, Wing Chi Yu. 2014-08-10. Spectral function and fidelity susceptibility in quantum critical phenomena. https://doi.org/10.1209/0295-5075%2F108%2F20002

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