11,022 research outputs found
Contrasting Nodal and Anti-Nodal Behavior in the Cuprates Via Multiple Gap Spectroscopies
Using a precursor superconductivity scenario for the cuprates we present a
theory for the temperature dependent behavior of the spectral gaps associated
with four distinct spectroscopies: angle resolved photoemission (ARPES),
differential conductance , quasi-particle interference spectroscopy, and
the autocorrelated ARPES pattern. We find good agreement for a range of
existing experiments and make predictions for others. Our theory, which
incorporates the necessary (observed) contrast between the nodal and anti-nodal
response, shows how different nodal gap shapes are associated with these
alternative spectroscopies.Comment: 4 pages, 3 figure
Microscopic Approach to Shear Viscosities in Superfluid Gases: From BCS to BEC
We compute the shear viscosity, , at general temperatures , in a
BCS-BEC crossover scheme which is demonstrably consistent with conservation
laws. The study of is important because it constrains microscopic
theories by revealing the excitation spectra. The onset of a normal state
pairing gap and the contribution from pair degrees of freedom imply that
at low becomes small, rather than exhibiting the upturn predicted by most
others. Using the local density approximation, we find quite reasonable
agreement with just-published experiments.Comment: 4 pages, 2 figure
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