5,831 research outputs found
Analytical treatment of SUSY Quasi-normal modes in a non-rotating Schwarzschild black hole
We use the Fock-Ivanenko formalism to obtain the Dirac equation which
describes the interaction of a massless 1/2-spin neutral fermion with a
gravitational field around a Schwarzschild black hole (BH). We obtain
approximated analytical solutions for the eigenvalues of the energy
(quasi-normal frequencies) and their corresponding eigenstates (quasi-normal
states). The interesting result is that all the excited states [and their
supersymmetric (SUSY) partners] have a purely imaginary frequency, which can be
expressed in terms of the Hawking temperature. Furthermore, as one expects for
SUSY Hamiltonians, the isolated bottom state has a real null energy eigenvalue.Comment: Version to be published in European Physical Journal
Hydrodynamic Limit for an Hamiltonian System with Boundary Conditions and Conservative Noise
We study the hyperbolic scaling limit for a chain of N coupled anharmonic
oscillators. The chain is attached to a point on the left and there is a force
(tension) acting on the right. In order to provide good ergodic
properties to the system, we perturb the Hamiltonian dynamics with random local
exchanges of velocities between the particles, so that momentum and energy are
locally conserved. We prove that in the macroscopic limit the distributions of
the elongation, momentum and energy, converge to the solution of the Euler
system of equations, in the smooth regime.Comment: New deeply revised version. 1 figure adde
Роздуми про розвиток фізики у ХХІ столітті
We analyze the impact of product bundling in experimental markets. One firm has monopoly power in a first market but competes with another firm à la Cournot in a second market. We compare treatments where the multi-product firm (i) always bundles, (ii) never bundles, and (iii) chooses whether to bundle. We also contrast the simultaneous and the sequential order of moves in the duopoly market. Our data indicate support for the theory of product bundling: with bundling and simultaneous moves, the multi-product firm offers the predicted number of units. When the multi-product firm is the Stackelberg leader, the predicted equilibrium is better attained with bundling, especially when it chooses to bundle, even though in theory bundling should not make a difference here. In sum, bundling works as a commitment device that enables the transfer of market power from one market to another
The Onset of Chaos in Spinning Particle Models
The onset of chaos in one-dimensional spinning particle models derived from
pseudoclassical mechanical hamiltonians with a bosonic Duffing potential is
examined. Using the Melnikov method, we indicate the presence of homoclinic
entanglements in models with general potentials for the spins, and thus show
that chaotic motions occur in these models.Comment: 9 pages in Revtex4 style, 4 figures (eps files
Regularity of squarefree monomial ideals
We survey a number of recent studies of the Castelnuovo-Mumford regularity of
squarefree monomial ideals. Our focus is on bounds and exact values for the
regularity in terms of combinatorial data from associated simplicial complexes
and/or hypergraphs.Comment: 23 pages; survey paper; minor changes in V.
The Onset of Chaotic Motion of a Spinning Particle around the Schwarzchild Black Hole
In the Schwarzchild black hole spacetime, we show that chaotic motion can be
triggered by the spin of a particle. Taking the spin of the particle as a
perturbation and using the Melnikov method, we find that the perturbed stable
and unstable orbits are entangled with each other and that illustrates the
onset of chaotic behavior in the motion of the particle.Comment: 14 pages in Revtex4 style, 9 figures(eps files
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