2,911 research outputs found
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
Industry Labor Force Quality: An Investigation from the Customer Service Perspective
To investigate the labor force quality deficiency in the Macao casino industry, this study conducted a survey among Macao casino guests on their assessment of customer service. The mean scores of different service features were calculated and compared across casinos operated by different casino companies. Furthermore, different service features were examined for their importance to the overall customer satisfaction based on an estimated regression model. The study found that most of the service features were below satisfactory rating, but Wynn Resorts stood out as the top performer among the four gaming companies. The regression model identified respect , smile and skill as the most important contributors to overall customer satisfaction. The findings suggest that to become a top gaming destination, Macao must strengthen its labor force quality in both technical and interpersonal skills
Probing positivity at the LHC with exclusive photon-fusion processes
By tagging one or two intact protons in the forward direction, it is possible
to select and measure exclusive photon-fusion processes at the LHC. The same
processes can also be measured in heavy ion collisions, and are often denoted
as ultraperipheral collisions (UPC) processes. Such measurements open up the
possibility of probing certain dimension-8 operators and their positivity
bounds at the LHC. As a demonstration, we perform a phenomenological study on
the processes, and find out that the
measurements of this process at the HL-LHC provide reaches on a set of
dimension-8 operator coefficients that are comparable to the ones at future
lepton colliders. We also point out that the process
could potentially have better reaches on similar types of operators due to its
larger cross section, but a more detailed experimental study is need to
estimate the signal and background rates of this process. The validity of
effective field theory (EFT) and the robustness of the positivity
interpretation are also discussed.Comment: 17 pages, 4 figures. v2: references added, minor correction
Fidelity susceptibility in the two-dimensional transverse field Ising and XXZ models
We study the fidelity susceptibility in the two-dimensional(2D) transverse
field Ising model and the 2D XXZ model numerically. It is found that in both
models, the fidelity susceptibility as a function of the driving parameter
diverges at the critical points. The validity of the fidelity susceptibility to
signal for the quantum phase transition is thus verified in these two models.
We also compare the scaling behavior of the extremum of the fidelity
susceptibility to that of the second derivative of the ground state energy.
From those results, the theoretical argument that fidelity susceptibility is a
more sensitive seeker for a second order quantum phase transition is also
testified in the two models.Comment: 6 pages, 7 figure
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