3,027 research outputs found
Hadronic Instabilities in Very Intense Magnetic Fields
Composite hadronic states exhibit interesting properties in the presence of
very intense magnetic fields, such as those conjectured to exist in the
vicinity of certain astrophysical objects. We discuss three scenarios. (i) The
presence of vector particles with anomalous magnetic moment couplings to scalar
particles, induces an instability of the vacuum. (ii) A delicate interplay
between the anomalous magnetic moments of the proton and neutron makes, in
magnetic fields T, the neutron stable and for fields
T the proton becomes unstable to a decay into a neutron
via emission. (iii) In the unbroken chiral model magnetic
fields would be screened out as in a superconductor. It is the explicit
breaking of chiral invariance that restores standard electrodynamics.
Astrophysical consequences of all these phenomena are discussed.Comment: Submitted to the 26th International Conference on High Energy Physics
(using macropackage REVTEX II), 10 page
Screening of Very Intense Magnetic Fields by Chiral Symmetry Breaking
In very intense magnetic fields, T, the breaking of
the strong interaction symmetry arranges itself so that
instead of the neutral field acquiring a vacuum expectation value it
is the charged field that does and the magnetic field is screened.
Details are presented for a magnetic field generated by a current in a wire; we
show that the magnetic field is screened out to a distance from the wire.Comment: 7 pages (using macropackage REVTEX II
Breaking of de Sitter Symmetry
We show that an interacting spin-0 field on a de Sitter space background will
break the underlying de Sitter symmetry. This is done first for a (1+1) de
Sitter space where a boson-fermion correspondence permits us to solve certain
interacting theories by transforming them into free ones of opposite
statistics. A massless boson interacting by a sine-Gordon potential is shown to
be equivalent to a free massive fermion with the mass depending on the de
Sitter time thus breaking the symmetry explicitly. We then show that for larger
dimensions and any boson potential, to one loop, an anomaly develops and the
currents generating the de Sitter transformations are not conserved.Comment: Talk at Quarks, Strings and the Cosmos - H\'{e}ctor Rubinstein
Memorial Symposium, August 09-11, 2010 AlbaNova)Stockholm) Sweden 12 pages, 1
figur
Quantum mechanics and field theory with momentum defined on an anti-de-Sitter space
Relativistic dynamics with energy and momentum resricted to an anti-de-Sitter
space is presented, specifically in the introduction of coordiate operators
conjugate to such momenta. Definition of functions of these operators, their
differentiation and integration, all necessary for the development of dynamics
is presented. The resulting algebra differs from the standard Heisenberg one,
notably in that the space-time coordinates do not commute among each other. The
resulting time variable is discrete and the limit to continuous time presents
difficulties. A parallel approach, in which an overlap function, between
position and momentum states, is obtained from solutions of wave equations on
this curved space are also investigated. This approach, likewise, has problems
in the that high energy behavior of these overlap functions precludes a
space-time definition of action functionals.Comment: 10 pages, presented at a Conference in Honor of Murray Gell-Mann's
80th Birthday, 24-26 February, 2010, Nanyang Technical University, Sigapor
Proton $\beta% decay in large magnetic fields
A delicate interplay between the anomalous magnetic moments of the proton and
neutron makes, in magnetic fields T, the neutron stable
and for fields T the proton becomes unstable to a decay
into a neutron via emission. Limits on the field strengths for which
these arguments hold are presented and are related to questions of vacuum
stability in the presence of such fields. Possible astrophysical consequences
are discussed.Comment: 12 page
Equations of Motion for Spinning Particles in External\\Electromagnetic and Gravitational Fields
The equations of motion for the position and spin of a classical particle
coupled to an external electromagnetic and gravitational potential are derived
from an action principle. The constraints insuring a correct number of
independent spin components are automatically satisfied. In general the spin is
not Fermi-Walker transported nor does the position follow a geodesic, although
the deviations are small for most situations.Comment: 7 pages set in Revtex I
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