5,007 research outputs found
Plasmon decay to a neutrino pair via neutrino electromagnetic moments in a strongly magnetized medium
We calculate the neutrino luminosity of a degenerate electron gas in a strong
magnetic field via plasmon decay to a neutrino pair due to neutrino
electromagnetic moments and obtain the relative upper bounds on the effective
neutrino magnetic moment.Comment: 3 pages, submitted to the Proceedings of the 16th Lomonosov
Conference on Elementary Particle Physics, Moscow State University, Moscow,
Russia, August 201
Wonderful blowups associated to group actions
A group action on a smooth variety provides it with the natural
stratification by irreducible components of the fixed point sets of arbitrary
subgroups. We show that the corresponding maximal wonderful blowup in the sense
of MacPherson-Procesi has only abelian stabilizers. The result is inspired by
the abelianization algorithm of Batyrev.Comment: 6 page
Spectral and localization properties of the Dirichlet wave guide with two concentric Neumann discs
Bound states of the Hamiltonian describing a quantum particle living on three
dimensional straight strip of width are investigated. We impose the Neumann
boundary condition on the two concentric windows of the radii and
located on the opposite walls and the Dirichlet boundary condition on the
remaining part of the boundary of the strip. We prove that such a system
exhibits discrete eigenvalues below the essential spectrum for any .
When and tend to the infinity, the asymptotic of the eigenvalue is
derived. A comparative analysis with the one-window case reveals that due to
the additional possibility of the regulating energy spectrum the anticrossing
structure builds up as a function of the inner radius with its sharpness
increasing for the larger outer radius. Mathematical and physical
interpretation of the obtained results is presented; namely, it is derived that
the anticrossings are accompanied by the drastic changes of the wave function
localization. Parallels are drawn to the other structures exhibiting similar
phenomena; in particular, it is proved that, contrary to the two-dimensional
geometry, at the critical Neumann radii true bound states exist.Comment: 25 pages, 7 figure
Homogenization of the planar waveguide with frequently alternating boundary conditions
We consider Laplacian in a planar strip with Dirichlet boundary condition on
the upper boundary and with frequent alternation boundary condition on the
lower boundary. The alternation is introduced by the periodic partition of the
boundary into small segments on which Dirichlet and Neumann conditions are
imposed in turns. We show that under the certain condition the homogenized
operator is the Dirichlet Laplacian and prove the uniform resolvent
convergence. The spectrum of the perturbed operator consists of its essential
part only and has a band structure. We construct the leading terms of the
asymptotic expansions for the first band functions. We also construct the
complete asymptotic expansion for the bottom of the spectrum
Nonlinear Realization of the Local Conform-Affine Symmetry Group for Gravity in the Composite Fiber Bundle Formalism
A gauge theory of gravity based on a nonlinear realization (NLR) of the local
Conform-Affine (CA) group of symmetry transformations is presented. The coframe
fields and gauge connections of the theory are obtained. The tetrads and
Lorentz group metric are used to induce a spacetime metric. The inhomogenously
transforming (under the Lorentz group) connection coefficients serve as
gravitational gauge potentials used to define covariant derivatives
accommodating minimal coupling of matter and gauge fields. On the other hand,
the tensor valued connection forms serve as auxillary dynamical fields
associated with the dilation, special conformal and deformational (shear)
degrees of freedom inherent in the bundle manifold. The bundle curvature of the
theory is determined. Boundary topological invariants are constructed. They
serve as a prototype (source free) gravitational Lagrangian. The Bianchi
identities, covariant field equations and gauge currents are obtained.Comment: 24 pages. to appear in IJGMM
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