1,518 research outputs found
N=4 Supersymmetric MICZ-Kepler systems on S3
Proceeding from the superfield action for nonlinear
supermultiplet, equipped with the most general potential term, we find the
action describing a charged particle on the sphere in the field of
fixed Dirac dyons. We construct the supercharges and Hamiltonian and analyze
some particulary interesting potentials corresponding to the N=4 supersymmetric
extension of the integrable one- and two-center
McIntosh--Cisneros--Zwanziger--Kepler (MICZ-Kepler) systems on .Comment: 8 pages, PACS: 11.30.Pb, 03.65.-w; corrected a misprint in (3.12),
added the last sentence on page 3, added the paragraph after (3.7), added the
sentence after (4.5
New insight into WDVV equation
We show that Witten-Dijkgraaf-Verlinde-Verlinde equation underlies the
construction of N=4 superconformal multi--particle mechanics in one dimension,
including a N=4 superconformal Calogero model.Comment: 16 pages, no figures, LaTeX file, PACS: 04.60.Ds; 11.30.P
Fermionic currents in AdS spacetime with compact dimensions
We derive a closed expression for the vacuum expectation value (VEV) of the
fermionic current density in a (D+1)-dimensional locally AdS spacetime with an
arbitrary number of toroidally compactified Poincare spatial dimensions and in
the presence of a constant gauge field. The latter can be formally interpreted
in terms of a magnetic flux treading the compact dimensions. In the compact
subspace, the field operator obeys quasiperiodicity conditions with arbitrary
phases. The VEV of the charge density is zero and the current density has
nonzero components along the compact dimensions only. They are periodic
functions of the magnetic flux with the period equal to the flux quantum and
tend to zero on the AdS boundary. Near the horizon, the effect of the
background gravitational field is small and the leading term in the
corresponding asymptotic expansion coincides with the VEV for a massless field
in the locally Minkowski bulk. Unlike the Minkowskian case, in the system
consisting an equal number of fermionic and scalar degrees of freedom, with
same masses, charges and phases in the periodicity conditions, the total
current density does not vanish. In these systems, the leading divergences in
the scalar and fermionic contributions on the horizon are canceled and, as a
consequence of that, the charge flux, integrated over the coordinate
perpendicular to the AdS boundary, becomes finite. We show that in odd
spacetime dimensions the fermionic fields realizing two inequivalent
representations of the Clifford algebra and having equal phases in the
periodicity conditions give the same contribution to the VEV of the current
density. Combining the contributions from these fields, the current density in
odd-dimensional C-,P- and T -symmetric models are obtained. As an application,
we consider the ground state current density in curved carbon nanotubes.Comment: 22 pages, 6 figures, PACS numbers: 04.62.+v, 03.70.+k, 98.80.-k,
61.46.F
Channeling of high-energy particles in a multi-wall nanotube
Channeling of high-energy particles in straight and bent multi-wall nanotubes
(MWNT) has been studied in computer simulations and compared to the channeling
properties of single-wall nanotubes (SWNT) and bent crystal lattices. It is
demonstrated that MWNT can efficiently channel positively-charged high-energy
particles trapped between the walls of MWNT. Bending dechanneling in MWNT has
been computed as a function of the particle momentum to nanotube curvature
radius ratio, . It is found that a bent MWNT can steer a particle beam
with bending capabilities similar to those of bent silicon crystal lattice and
to those of best (i.e. the narrowest) SWNT. In view of channeling applications
at particle accelerators, MWNT appear favored as compared to SWNT, because MWNT
can be produced quite straight (and in aligned array), while SWNT is typically
very curved, thus posing a severe problem for channeling applications.
Therefore, we suggest that MWNT provide a better candidate for channeling than
SWNT.Comment: 16 pages, 6 figures, to appear in Phys. Lett.
Making the hyper--K\"ahler structure of N=2 quantum string manifest
We show that the Lorentz covariant formulation of N=2 string in a curved
space reveals an explicit hyper--K\"ahler structure. Apart from the metric, the
superconformal currents couple to a background two--form. By superconformal
symmetry the latter is constrained to be holomorphic and covariantly constant
and allows one to construct three complex structures obeying a
(pseudo)quaternion algebra.Comment: 8 pages, no figures, PACS: 04.60.Ds; 11.30.Pb, Keywords: N=2 string,
hyper-K\"ahler geometry. Presentation improved, references added. The version
to appear in PR
Constant magnetic field and 2d non-commutative inverted oscillator
We consider a two-dimensional non-commutative inverted oscillator in the
presence of a constant magnetic field, coupled to the system in a
``symplectic'' and ``Poisson'' way. We show that it has a discrete energy
spectrum for some value of the magnetic field.Comment: 7 pages, LaTeX file, no figures, PACS number: 03.65.-
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