4,706 research outputs found
Quantum Cooling Evaporation Process in Regular Black Holes
We investigate a universal behavior of thermodynamics and evaporation process
for the regular black holes. We newly observe an important point where the
temperature is maximum, the heat capacity is changed from negative infinity to
positive infinity, and the free energy is minimum. Furthermore, this point
separates the evaporation process into the early stage with negative heat
capacity and the late stage with positive heat capacity. The latter represents
the quantum cooling evaporation process. As a result, the whole evaporation
process could be regarded as the inverse Hawking-Page phase transition.Comment: 11 pages, 3 figures, version to appear in Phys. Lett.
Exact Results for a Kondo Problem in One Dimensional t-J Model
We propose an integrable Kondo problem in a one-dimensional (1D) model.
With the open boundary condition of the wave functions at the impurity sites,
the model can be exactly solved via Bethe ansatz for a class of
(Kondo coupling constants) and (impurity potentials) parametrized by
a single parameter . The integrable value of runs from negative
infinity to positive infinity, which allows us to study both the ferromagnetic
Kondo problem and antiferromagnetic Kondo problem in a strongly correlated
electron system. Generally, there is a residual entropy for the ground state,
which indicates a typical non-Fermi liquid behavior.Comment: 5 pages Revtex, no figure
p-Brane cosmology and phases of Brans-Dicke theory with matter
We study the effect of the solitonic degrees of freedom in string cosmology
following the line of Rama. The gas of solitonic p-brane is treated as a
perfect fluid in a Brans-Dicke type theory. In this paper, we find exact
cosmological solutions for any Brans-Dicke parameter and for general
parameter of equation of state and classify the cosmology of the
solutions on a parameter space of and .Comment: 26 pages, 5 figures, Contents and references added; published in
Phys. Rev. D57(1998) 462
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