20,583 research outputs found
Strong Coupling Limit of Bethe Ansatz Solutions in Massive Thirring Model
We study the strong coupling limit of the Bethe ansatz solutions in the
massive Thirring model. We find analytical expressions for the energy
eigenvalues for the vacuum state as well as n-particle n- hole states. This
formula is compared with the numerical results and is found to achieve a very
good agreement.
Also, it is found that the 2-particle 2- hole and higher particle-hole states
describe n- free bosons states in this limit. The behaviors of the strong
coupling limit of the boson mass for various model calculations are examined.
We discuss an ambiguity of the coupling constant normalization due to the
current regularization.Comment: 15 pages, to appear in Ann. Phys. 281 (2000), Ma
New Numerical Methods to Evaluate Homogeneous Solutions of the Teukolsky Equation
We discuss a numerical method to compute the homogeneous solutions of the
Teukolsky equation which is the basic equation of the black hole perturbation
method. We use the formalism developed by Mano, Suzuki and Takasugi, in which
the homogeneous solutions of the radial Teukolsky equation are expressed in
terms of two kinds of series of special functions, and the formulas for the
asymptotic amplitudes are derived explicitly.Although the application of this
method was previously limited to the analytical evaluation of the homogeneous
solutions, we find that it is also useful for numerical computation. We also
find that so-called "renormalized angular momentum parameter", , can be
found only in the limited region of for each if we assume
is real (here, is the angular frequency, and and are degree
and order of the spin-weighted spheroidal harmonics respectively). We also
compute the flux of the gravitational waves induced by a compact star in a
circular orbit on the equatorial plane around a rotating black hole. We find
that the relative error of the energy flux is about which is much
smaller than the one obtained by usual numerical integration methods.Comment: 36 pages,7 figure
Non-equivalence between Heisenberg XXZ spin chain and Thirring model
The Bethe ansatz equations for the spin 1/2 Heisenberg XXZ spin chain are
numerically solved, and the energy eigenvalues are determined for the
anti-ferromagnetic case. We examine the relation between the XXZ spin chain and
the Thirring model, and show that the spectrum of the XXZ spin chain is
different from that of the regularized Thirring model.Comment: 10 pages. 2figure
A proposed method of estimating cloud-top temperature, cloud covers, emissivity, and cloudness from short and long wave radiation data obtained by medium-resolution scanning radiometers
Tiros medium resolution scanning radiometer data from short and long wavelengths used to estimate cloud top temperatures, cloud cover, emissivity, and equivalent black body temperature
Boundary migration and disappearance of voids in Alpha-Al2O3 at 2000 deg C
A series of photographs taken with Osaka University's high temperature 3MV electron microscope of alpha-A1(z)O(3) at 2000 C is presented. The dynamic study shows grain boundary migration in progress and demonstrates that disappearance of voids is controlled by boundary migration
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