560 research outputs found
Axion Decay in a Constant Electromagnetic Background Field and at Finite Temperature using World-line Methods
We investigate the radiative decay of the axion into two photons in an
external electromagnetic field to one loop order. Our approach is based on the
world-line formalism, which is very suitable to take into account the external
field to all orders. Afterwards we discuss how the calculation could be
generalized to finite temperature.Comment: 27 pages, 4 figures, corrected and added some references and added
some remarks to appendix
Nonlinear viscous hydrodynamics in various dimensions using AdS/CFT
We compute coefficients of two-derivative terms in the hydrodynamic energy
momentum tensor of a viscous fluid which has an AdS_D dual with D between 3 and
7. For the case of D=3 we obtain an exact AdS_3 black hole solution, valid to
all orders in a derivative expansion, dual to a perfect fluid in 1+1
dimensions.Comment: 20 pages; typos corrected, references adde
Glauber coherence of single electron sources
Recently demonstrated solid state single electron sources generate different
quantum states depending on their operation condition. For adiabatic and
non-adiabatic sources we determine the Glauber correlation function in terms of
the Floquet scattering matrix of the source. The correlation function provides
full information on the shape of the state, on its time-dependent amplitude and
phase, which makes the coherence properties of single electron states essential
for the production of quantum multi-particle states.Comment: 4+ pages, 4 figure
Jumping Through Loops: On Soft Terms from Large Volume Compactifications
We subject the phenomenologically successful large volume scenario of
hep-th/0502058 to a first consistency check in string theory. In particular, we
consider whether the expansion of the string effective action is consistent in
the presence of D-branes and O-planes. Due to the no-scale structure at
tree-level, the scenario is surprisingly robust. We compute the modification of
soft supersymmetry breaking terms, and find only subleading corrections. We
also comment that for large-volume limits of toroidal orientifolds and fibered
Calabi-Yau manifolds the corrections can be more important, and we discuss
further checks that need to be performed.Comment: 57 page
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