16,762 research outputs found
Non-Anticommutative Deformations of N=(1,1) Supersymmetric Theories
We discuss chirality-preserving nilpotent deformations of four-dimensional
N=(1,1) Euclidean harmonic superspace and their implications in N=(1,1)
supersymmetric gauge and hypermultiplet theories, basically following
[hep-th/0308012] and [hep-th/0405049]. For the SO(4) x SU(2) invariant
deformation, we present non-anticommutative Euclidean analogs of the N=2 gauge
multiplet and hypermultiplet off-shell actions. As a new result, we consider a
specific non-anticommutative hypermultiplet model with N=(1,0) supersymmetry.
It involves free scalar fields and interacting right-handed spinor fields.Comment: Latex file, 15 pages, Submitted to Proceedings of the Seminar
``Classical and Quantum Integrable Systems'' (Dubna, Russia, January 26-29,
2004), v.2 with minor correction
Self-Dual N=2 Born-Infeld Theory Through Auxiliary Superfields
There is an evidence that the N=2 Born-Infeld theory with spontaneously
broken N=4 supersymmetry exhibits self-duality. We perform a further check of
this hypothesis by constructing a new representation for the N=2 Born-Infeld
action through the auxiliary chiral superfield U. In such a formulation,
self-duality is equivalent to U(1) invariance of the U interaction. We
explicitly calculate the auxiliary interaction up to the 10th order and show
its U(1) duality invariance, thus proving that the original action is self-dual
to the same order. We also suggest a new method of recursive computation of the
N=2 Born-Infeld action in the standard formulation, based solely on the
nonlinear realization of the N=4 central charge on the N=2 superfield strengths
W, \bar W.Comment: 1 + 31 pages, substantial revision: an important Note and Appendix C
added; section 2 corrected and expanded; some typos, eq. (5.13) and Appendix
B correcte
Magnon modes for thin circular vortex state magnetic dot
The magnetization in a magnetic microdot made from soft magnetic materials
can have a vortex-like ground state structure resulting from competition
between the exchange and dipolar interactions. Normal mode magnon frequencies
for such dots are calculated taking into account both exchange and
magnetostatic effects. The presence of a low-lying mode as well as doublet
structure with small splitting is demonstrated. Estimates of the mode
frequencies for permalloy dots are obtained, and the possibility of
experimental detection of such modes is discussed.Comment: 5 pages, 2 figure
Chirality tunneling in mesoscopic antiferromagnetic domain walls
We consider a domain wall in the mesoscopic quasi-one-dimensional sample
(wire or stripe) of weakly anisotropic two-sublattice antiferromagnet, and
estimate the probability of tunneling between two domain wall states with
different chirality. Topological effects forbid tunneling for the systems with
half-integer spin S of magnetic atoms which consist of odd number of chains N.
External magnetic field yields an additional contribution to the Berry phase,
resulting in the appearance of two different tunnel splittings in any
experimental setup involving a mixture of odd and even N, and in oscillating
field dependence of the tunneling rate with the period proportional to 1/N.Comment: 4 pages + 2 figures, references correcte
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