46,424 research outputs found
Non-Commutativity, Teleology and GRB Time Delay
We propose a model in which an energy-dependent time delay of a photon
originates from space-time non-commutativity, the time delay is due to a
noncommutative coupling between dilaton and photon. We predict that in our
model, high energy photons with different momenta can either be delayed or
superluminal, this may be related to a possible time delay reported by the
Fermi LAT and Fermi GBM Collaborations.Comment: 8 pages, 1 figure, typo revised, contents and reference adde
Renormalization-group exponents for superconducting phases in two-leg ladders
In previous studies, we proposed a scaling ansatz for electron-electron
interactions under renormalization group transformation. With the inclusion of
phonon-mediated interactions, we show that the scaling ansatz, characterized by
the divergent logarithmic length and a set of renormalization-group
exponents, also works rather well. The superconducting phases in a doped
two-leg ladder are studied and classified by these renormalization-group
exponents as demonstration. Finally, non-trivial constraints among the
exponents are derived and explained.Comment: 4 pages, 3 figures; minor revisions with references adde
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