2,194 research outputs found
A Derivation of the Fermi Function in Perturbative Quantum Field Theory
We postulate that the Fermi function should be derived from the amplitude,
not from the solution of the Dirac equation, in the quantum field theory.
Then, we obtain the following results.
1, We give the amplitude and the width of the neutron beta decay, to one loop order. It is carried out by the Feynman
parameter integration.
2, As the result, we find the terms which can be interpreted as the Fermi
function expanded to order .
3, We also give the same result using complex analysis.
4, We check that there are no such terms in the similar process, .
5, We perform the Fermi function expanded to order using complex
analysis.Comment: 8 page
D3/D7 holographic Gauge theory and Chemical potential
N=2 supersymmetric Yang-Mills theory with flavor hypermultiplets at finite
temperature and in the dS are studied for finite quark number density
() by a dual supergravity background with non-trivial dilaton and axion.
The quarks and its number density are introduced by embedding a probe D7
brane. We find a critical value of the chemical potential at the limit of
, and it coincides with the effective quark mass given in each theory
for . At this point, a transition of the D7 embedding configurations
occurs between their two typical ones. The phase diagrams of this transition
are shown in the plane of chemical potential versus temperature and
cosmological constant for YM theory at finite temperature and in dS
respectively. In this phase transition, the order parameter is considered as
. % and the critical value of the chemical potential This result seems to
be reasonable since both theories are in the quark deconfinement phase.Comment: 17 pages, 8 figure
Algebraic structure of the Feynman propagator and a new correspondence for canonical transformations
We investigate the algebraic structure of the Feynman propagator with a
general time-dependent quadratic Hamiltonian system. Using the Lie-algebraic
technique we obtain a normal-ordered form of the time-evolution operator, and
then the propagator is easily derived by a simple ``Integration Within Ordered
Product" (IWOP) technique.It is found that this propagator contains a classical
generating function which demonstrates a new correspondence between classical
and quantum mechanics
Asymptotically AdS brane black holes
We study the possibility of having a static, asymptotically AdS black hole
localized on a braneworld with matter fields, within the framework of the
Randall and Sundrum scenario. We attempt to look for such a brane black hole
configuration by slicing a given bulk spacetime and taking Z_2 symmetry about
the slices. We find that such configurations are possible, and as an explicit
example, we provide a family of asymptotically AdS brane black hole solutions
for which both the bulk and brane metrics are regular on and outside the black
hole horizon and brane matter fields are realistic in the sense that the
dominant energy condition is satisfied. We also find that our braneworld models
exhibit signature change inside the black hole horizon.Comment: 21 pages, 6 figures, RevTex; v2: clarifications added, figures
updated, eq.31 corrected, comment on small four dimensional cosmological
constant limit added, character size increased, results unchanged. v3:
reference added, version accepted in Phys. Rev. D (2006
Rate-determining process in MISIM photocells for optoelectronic conversion using photo-induced pure polarization current without carrier transfer across interfaces
Recently, we proposed a [metal|insulator|semiconductor|insulator|metal] (MISIM) photocell, as a novel architecture for high-speed organic photodetectors. The electric polarization in the S layer, induced by modulated light illumination, propagates into the outside circuit as a polarization current through the I layers, without any carrier transfer across the interfaces. In the present work, we examined the MISIM photocells consisting of zinc-phthalocyanine(ZnPc)-C60 bilayers for the S layer and Parylene C for the two I layers, to understand the fundamental aspects of the MISIM photocells, such as current polarity and modulation-frequency dependence. It was found that, in such devices, the current polarity was primarily determined by the polarization in the S layer, which was induced by the donor–acceptor charge-transfer upon illumination. Furthermore, the ON and OFF current, which appeared in the periods of illumination-on and -off, respectively, exhibited significantly different dependence on the modulation frequency. This was well-explained by an imbalance between a quick polarization in the S layer during illumination and its slow relaxation in the dark
Meson mass and confinement force driven by dilaton
Meson spectra given as fluctuations of a D7 brane are studied under the
background driven by the dilaton. This leads to a dual gauge theory with quark
confinement due to the gauge condensate. We find that the effect of the gauge
condensate on the meson spectrum is essential in order to make a realistic
hadron spectrum in the non-supersymmetric case. In the supersymmetric case,
however, only the spectra of the scalars are affected, but they are changed in
an opposite way compared to the non-supersymmetric case.Comment: 11 pages, 2 figure
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