603 research outputs found
Application of symbol-operator technique for effective action computation
In the present talk we briefly demonstrate an elegant and effective technique
for calculation of the trace expansion in the derivatives of background fields.
One of main advantages of the technique is manifestly (super)symmetrical and
gauge invariant form of expressions on all stages of calculations. Other
advantage is the universality of the calculation method. Some particular
examples and results are presented.Comment: 11 pages, LaTex, Extended version of the talk given at the Fifth
Workshop on Quantum Field Theory under the Influence of External Conditions,
Leipzig, 10-15 Sept. 200
One-loop effective potential in generic chiral superfield model
We obtain the one-loop quantum corrections to the K\"ahlerian and
superpotentials in the generic chiral superfield model on the
nonanticommutative superspace. Unlike all previous works, we use a method which
does not require to rewrite a star-product of superfields in terms of ordinary
products. In the K\"ahlerian potential sector the one-loop contributions are
analogous to ones in the undeformed theory while in the chiral potential sector
the quantum corrections contain a deformation parameter.Comment: LaTeX, 9 pages, Typos correcte
Collective effects in charge transfer within a hybrid organic-inorganic system
A collective electron transfer (ET) process was discovered by studying the
current noise in a field effect transistor with light-sensitive gate formed by
nanocrystals linked by organic molecules to its surface. Fluctuations in the ET
through the organic linker are reflected in the fluctuations of the transistor
conductivity. The current noise has an avalanche character. Critical exponents
obtained from the noise power spectra, avalanche distributions, and the
dependence of the average avalanche size on avalanche duration are consistent
with each other. A plausible model is proposed for this phenomenonComment: 15 pages 4 figures. Accepted for publication in Physical Review
Letter
Size dependent tunneling and optical spectroscopy of CdSe quantum rods
Photoluminescence excitation spectroscopy and scanning tunneling spectroscopy
are used to study the electronic states in CdSe quantum rods that manifest a
transition from a zero dimensional to a one dimensional quantum confined
structure. Both optical and tunneling spectra show that the level structure
depends primarily on the rod diameter and not on length. With increasing
diameter, the band-gap and the excited state level spacings shift to the red.
The level structure was assigned using a multi-band effective-mass model,
showing a similar dependence on rod dimensions.Comment: Accepted to PRL (nearly final version). 4 pages in revtex, 4 figure
- …