33,400 research outputs found
Triple Products and Yang-Baxter Equation (II): Orthogonal and Symplectic Ternary Systems
We generalize the result of the preceeding paper and solve the Yang-Baxter
equation in terms of triple systems called orthogonal and symplectic ternary
systems. In this way, we found several other new solutions.Comment: 38 page
A new screening function for Coulomb renormalization
We introduce a new screening function which is useful for the few-body
Coulomb scattering problem in ``screening and renormalization'' scheme. The new
renormalization phase factor of the screening function is analytically shown.
The Yukawa type of the screening potential has been used in several decades, we
modify it to make more useful. As a concrete example, we compare the
proton-proton scattering phase shifts calculated from these potentials. The
numerical results document that high precision calculations of the
renormalization are performed by the new screening function.Comment: 4 pages, 8 figure
Black Strings in Our World
The brane world scenario is a new approach to resolve the problem on how to
compactify the higher dimensional spacetime to our 4-dimensional world. One of
the remarkable features of this scenario is the higher dimensional effects in
classical gravitational interactions at short distances. Due to this feature,
there are black string solutions in our 4-dimensional world. In this paper,
assuming the simplest model of complex minimally coupled scalar field with the
local U(1) symmetry, we show a possibility of black-string formation by merging
processes of type I long cosmic strings in our 4-dimensional world. No fine
tuning for the parameters in the model might be necessary.Comment: 11pages, no figur
Phase transition of color-superconductivity and cooling behavior of quark stars
We discuss the color-superconductivity and its effect on the cooling behavior
of strange quark stars. The neutrino emissivity and specific heat of quark
matter are calculated within the BCS theory. In the superconducting phase, the
emissivity decreases and causes suppression of the cooling rate. It is shown
that the phase transition leads to a sudden discontinuous suppression of the
cooling rate in cooperation with the specific heat.Comment: 7 pages, 3 figure
Bogoliubov quasiparticle spectra of the effective d-wave model for cuprate superconductivity
An exact-diagonalization technique on finite-size clusters is used to study
the ground state and excitation spectra of the two-dimensional effective
fermion model, a fictious model of hole quasiparticles derived from numerical
studies of the two-dimensional t-J model at low doping. We show that there is
actually a reasonable range of parameter values where the -wave
pairing of holes occurs and the low-lying excitation can be described by the
picture of Bogoliubov quasiparticles in the BCS pairing theory. The gap
parameter of a size (where is the attractive
interaction between holes) is estimated at low doping levels. The paired state
gives way to the state of clustering of holes for some stronger attractions.Comment: 4 pages, RevTeX. Figures available upon request to
[email protected]. To be published in Phys. Rev.
Geometric Bremsstrahlung in the Early Universe
We discuss photon emission from particles decelerlated by the cosmic
expansion. This can be interpretated as a kind of bremsstrahlung induced by the
Universe geometry. In the high momentum limit its transition probability does
not depend on detailed behavior of the expansion.Comment: 20 pages, No figure
- …