8,665 research outputs found
Gauging Nonlinear Supersymmetry
Coset methods are used to construct the action describing the dynamics
associated with the spontaneous breaking of the local supersymmetries. The
resulting action is an invariant form of the Einstein-Hilbert action, which in
addition to the gravitational vierbein, also includes a massive gravitino
field. Invariant interactions with matter and gauge fields are also
constructed. The effective Lagrangian describing processes involving the
emission or absorption of a single light gravitino is analyzed.Comment: 20 pages, no figure
Voltage-controlled Group Velocity of Edge Magnetoplasmon in the Quantum Hall Regime
We investigate the group velocity of edge magnetoplasmons (EMPs) in the
quantum Hall regime by means of time-of-flight measurement. The EMPs are
injected from an Ohmic contact by applying a voltage pulse, and detected at a
quantum point contact by applying another voltage pulse to its gate. We find
that the group velocity of the EMPs traveling along the edge channel defined by
a metallic gate electrode strongly depends on the voltage applied to the gate.
The observed variation of the velocity can be understood to reflect the degree
of screening caused by the metallic gate, which damps the in-plane electric
field and hence reduces the velocity. The degree of screening can be controlled
by changing the distance between the gate and the edge channel with the gate
voltage.Comment: 5 pages, 6 figures, to be published in Physical Review
Total Polarisation Conversion in Two-dimensional Electron System under Cyclotron Resonance Conditions
The polarisation conversion of a linear polarised electromagnetic wave
incident onto a two-dimensional (2D) electron system at an angle is
theoretically studied. We consider the 2D system located at the interface
between two dielectric media with different dielectric constants. An external
dc magnetic field is assumed to be directed along the normal to the 2D electron
layer. In such a configuration the cyclotron-polaritons (CPs) in 2D electron
system can be excited with the frequencies in the vicinity of the cyclotron
frequency. Under the CPs excitation the resonance polarisation conversion of
electromagnetic wave greatly increases in the system. In the absence of the
electron scattering in 2D system, the polarisation conversion reaches 100% at a
certain value of the angle of incidence which is more than the total reflection
angle. Extremely high polarisation conversion takes place in a quite wide range
of variation of the angle of incidence. High polarisation conversion efficiency
(above 80%) remains when the actual electron scattering in the 2D system on
GsAs is taken into account. The considered phenomena may be taken up in
polarisation spectroscopy of 2D electron systems.Comment: 7 pages, 5 Postscript figure
Even and odd symplectic and K\"ahlerian structures on projective superspaces
Supergeneralization of \DC P(N) provided by even and odd K\"ahlerian
structures from Hamiltonian reduction are construct.Operator which
used in Batalin-- Vilkovisky quantization formalism and mechanics which are
bi-Hamiltonian under corresponding even and odd Poisson brackets are
considered.Comment: 19 page
Two-photon decays of vector mesons and dilepton decays of scalar mesons in dense matter
Two-photon decays of vector mesons and dilepton decays of scalar mesons which
are forbidden in vacuum and can occur in dense baryonic matter due to the
explicit violation of Lorentz symmetry are described within a quark model of
the Nambu--Jona-Lasinio type. The temperature and chemical potential dependence
of these processes is investigated. It is found that their contribution to the
production of photons and leptons in heavy-ion collisions is enhanced near the
conditions corresponding to the restoration of chiral symmetry. Moreover, in
the case of the a_0 meson and especially the \rho-meson, a resonant behaviour
(an additional amplification) is observed due to the degeneration of \rho and
a_0 masses when a hot hadron matter is approaching a chirally symmetric phase.Comment: 20 figures, IOP styl
Superconformal Symmetry, The Supercurrent And Non-BPS Brane Dynamics
The Noether currents associated with the non-linearly realized
super-Poincare' symmetries of the Green-Schwarz (Nambu-Goto-Akulov-Volkov)
action for a non-BPS p=2 brane embedded in a N=1, D=4 target superspace are
constructed. The R symmetry current, the supersymmetry currents, the
energy-momentum tensor and the scalar central charge current are shown to be
components of a world volume supercurrent. The centrally extended
superconformal transformations are realized on the Nambu-Goldstone boson and
fermion fields of the non-BPS brane. The superconformal currents form
supersymmetry multiplets with the world volume conformal central charge current
and special conformal current being the primary components of the supersymmetry
multiplets containing all the currents. Correspondingly the superconformal
symmetry breaking terms form supersymmetry multiplets the components of which
are obtainable as supersymmetry transformations of the primary currents'
symmetry breaking terms.Comment: 27 pages, LaTeX, Summary Tables Adde
AdS-Carroll Branes
Coset methods are used to determine the action of a co-dimension one brane
(domain wall) embedded in (d+1)-dimensional AdS space in the Carroll limit in
which the speed of light goes to zero. The action is invariant under the
non-linearly realized symmetries of the AdS-Carroll spacetime. The
Nambu-Goldstone field exhibits a static spatial distribution for the brane with
a time varying momentum density related to the brane's spatial shape as well as
the AdS-C geometry. The AdS-C vector field dual theory is obtained.Comment: 47 page
Nonlinear Resonance of Superconductor/Normal Metal Structures to Microwaves
We study the variation of the differential conductance of a normal
metal wire in a Superconductor/Normal metal heterostructure with a cross
geometry under external microwave radiation applied to the superconducting
parts. Our theoretical treatment is based on the quasiclassical Green's
functions technique in the diffusive limit. Two limiting cases are considered:
first, the limit of a weak proximity effect and low microwave frequency,
second, the limit of a short dimension (short normal wire) and small
irradiation amplitude.Comment: 11 pages, 10 figure
Nonlinear realization of local symmetries of AdS space
Coset methods are used to construct the action describing the dynamics
associated with the spontaneous breaking of the local symmetries of AdS_{d+1}
space due to the embedding of an AdS_d brane. The resulting action is an
SO(2,d) invariant AdS form of the Einstein-Hilbert action, which in addition to
the AdS_d gravitational vielbein, also includes a massive vector field
localized on the brane. Its long wavelength dynamics is the same as a massive
Abelian vector field coupled to gravity in AdS_d space.Comment: 17 page
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