17,603 research outputs found
Scaling dimension of fidelity susceptibility in quantum phase transitions
We analyze ground-state behaviors of fidelity susceptibility (FS) and show
that the FS has its own distinct dimension instead of real system's dimension
in general quantum phases. The scaling relation of the FS in quantum phase
transitions (QPTs) is then established on more general grounds. Depending on
whether the FS's dimensions of two neighboring quantum phases are the same or
not, we are able to classify QPTs into two distinct types. For the latter type,
the change in the FS's dimension is a characteristic that separates two phases.
As a non-trivial application to the Kitaev honeycomb model, we find that the FS
is proportional to in the gapless phase, while in the gapped
phase. Therefore, the extra dimension of can be used as a
characteristic of the gapless phase.Comment: 4 pages, 1 figure, final version to appear in EP
Spectral function and fidelity susceptibility in quantum critical phenomena
In this paper, we derive a simple equality that relates the spectral function
and the fidelity susceptibility , i.e. with 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.Comment: 5 pages, 2 figure
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