6,103 research outputs found
Fate of Inhomogeneity in Schwarzschild-deSitter Space-time
We investigate the global structure of the space time with a spherically
symmetric inhomogeneity using a metric junction, and classify all possible
types. We found that a motion with a negative gravitational mass is possible
although the energy condition of the matter is not violated. Using the result,
formation of black hole and worm hole during the inflationary era is discussed.Comment: 6page
Axionic Membranes
A metal ring removed from a soap-water solution encloses a film of soap which
can be mathematically described as a minimal surface having the ring as its
only boundary. This is known to everybody. In this letter we suggest a
relativistic extension of the above fluidodynamic system where the soap film is
replaced by a Kalb-Ramond gauge potential \b(x) and the ring by a closed
string. The interaction between the \b-field and the string current excites a
new configuration of the system consisting of a relativistic membrane bounded
by the string. We call such a classical solution of the equation of motion an
axionic membrane. As a dynamical system, the axionic membrane admits a
Hamilton-Jacobi formulation which is an extension of the H-J theory of
electromagnetic strings.Comment: 15 page
Top Condensation without Fine-Tuning
Quadratic divergencies which lead to the usual fine-tuning or hierarchy
problem are discussed in top condensation models. As in the Standard Model a
cancellation of quadratic divergencies is not possible without the boson
contributions in the radiative corrections which are absent in lowest order of
an -expansion. To deal with the cancellation of quadratic divergencies
we propose therefore an expansion in the flavor degrees of freedom. In leading
order we find the remarkable result that quadratic divergencies automatically
disappear.Comment: LMU - 17/93, in LATEX, 12 pages and 3 pages of figures appended in
Postscrip
Black Objects in the Gauge Theory of P-Branes
Within the context of the recently formulated classical gauge theory of
relativistic p-branes minimally coupled to general relativity in D-dimensional
spacetimes, we obtain solutions of the field equations which describe black
objects. Explicit solutions are found for two cases: D > p+1 (true p-branes)
and D = p+1 (p-bags).Comment: 9 pages, REVTEX 3.
Supersymmetry And Electron-hole Excitation in Semiconductor At Finite Temperature
The fermionic and bosonic electron-hole low lying excitations in a
semiconductor are analyzed at finite temperature in a unified way following
Nambu's quasi-supersymmetric approach for the BCS model of superconductivity.
The effective lagrangian for the fermionic modes and for the bosonic low lying
collective excitations in the semiconductor is no longer supersymmetric in a
conventional finite temperature treatment. However the bosonic excitations
don't couple directly to the heat bath and as a result, quasisupersymmetry is
restored to the effective lagrangian when a redefinition of the coupling
constant associated with the collective excitations is performed. Our result
shows that although the mass and coupling parameters are now temperature
dependent, the fermion and boson excited states pair together and can still be
transmuted into one another.Comment: 23 pages with 3 independent EPS figures; to appear in Nulear Physics
Instability of Massive Scalar Fields in Kerr-Newman Spacetime
We investigate the instability of charged massive scalar fields in
Kerr-Newman spacetime. Due to the super-radiant effect of the background
geometry, the bound state of the scalar field is unstable, and its amplitude
grows in time. By solving the Klein-Gordon equation of the scalar field as an
eigenvalue problem, we numerically obtain the growth rate of the amplitude of
the scalar field. Although the dependence of the scalar field mass and the
scalar field charge on this growth rate agrees with the result of the analytic
approximation, the maximum value of the growth rate is three times larger than
that of the analytic approximation. We also discuss the effect of the electric
charge on the instability of the scalar field.Comment: 15 pages, 10 figures. Accepted for publication in Prog.Theor.Phy
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