321 research outputs found
"Root" Action for N=4 Supersymmetric Mechanics Theories
We propose to consider the N=4,d=1 supermultiplet with $% (4,4,0) component
content as a ``root'' one. We elaborate a new reduction scheme from the
``root'' multiplet to supermultiplets with a smaller number of physical bosons.
Starting from the most general sigma-model type action for the ``root''
multiplet, we explicitly demonstrate that the actions for the rest of linear
and nonlinear N=4 supermultiplets can be easily obtained by reduction.
Within the proposed reduction scheme there is a natural possibility to
introduce Fayet-Iliopoulos terms. In the reduced systems, such terms give rise
to potential terms, and in some cases also to terms describing the interaction
with a magnetic field.
We demonstrate that known N=4 superconformal actions, together with their
possible interactions, appear as results of the reduction from a free action
for the ``root'' supermultiplet. As a byproduct, we also construct an N=4
supersymmetric action for the linear (3,4,1) supermultiplet, containing both an
interaction with a Dirac monopole and a harmonic oscillator-type potential,
generalized for arbitrary conformally flat metrics.Comment: 12 page
Motion of a spin 1/2 particle in shape invariant scalar and magnetic fields
We study the motion of a spin 1/2 particle in a scalar as well as a magnetic
field within the framework of supersymmetric quantum mechanics(SUSYQM). We also
introduce the concept of shape invariant scalar and magnetic fields and it is
shown that the problem admits exact analytical solutions when such fields are
considered.Comment: 14 page
Pauli equation and the method of supersymmetric factorization
We consider different variants of factorization of a 2x2 matrix
Schroedinger/Pauli operator in two spatial dimensions. They allow to relate its
spectrum to the sum of spectra of two scalar Schroedinger operators, in a
manner similar to one-dimensional Darboux transformations. We consider both the
case when such factorization is reduced to the ordinary 2-dimensional SUSY QM
quasifactorization and a more general case which involves covariant
derivatives. The admissible classes of electromagnetic fields are described and
some illustrative examples are given.Comment: 18 pages, Late
A Generalization of the Bargmann-Fock Representation to Supersymmetry by Holomorphic Differential Geometry
In the Bargmann-Fock representation the coordinates act as bosonic
creation operators while the partial derivatives act as
annihilation operators on holomorphic -forms as states of a -dimensional
bosonic oscillator. Considering also -forms and further geometrical objects
as the exterior derivative and Lie derivatives on a holomorphic , we
end up with an analogous representation for the -dimensional supersymmetric
oscillator. In particular, the supersymmetry multiplet structure of the Hilbert
space corresponds to the cohomology of the exterior derivative. In addition, a
1-complex parameter group emerges naturally and contains both time evolution
and a homotopy related to cohomology. Emphasis is on calculus.Comment: 11 pages, LaTe
A nuclear factor 1 binding site mediates the transcriptional activation of a type I collagen promoter by transforming growth factor-beta
Transforming growth factor-beta (TGF-beta) increases the steady-state RNA levels of several fibroblast extracellular matrix proteins. Using DNA transfection, we show that TGF-beta stimulates the activity of the mouse alpha 2(l) collagen promoter 5- to 10-fold in mouse NIH 3T3 and rat osteosarcoma cells. Deletion analysis indicates that a segment of this promoter between -350 and -300, overlapping a nuclear factor 1 (NF1) binding site, is needed for TGF-beta stimulation. A 3 bp substitution mutation abolishing NF1 binding to this site inhibits TGF-beta activation. Insertion of this NF1 binding site 5' to the SV40 early promoter makes the promoter TGF-beta inducible, but the 3 bp substitution does not. Similarly, when the NF1 binding site at the replication origin of adenovirus 2 and 5 is inserted 5' to the SV40 promoter, the promoter responds to TGF-beta. Therefore an NF1 binding site mediates the transcriptional activation of the mouse alpha 2(l) collagen promoter by TGF-beta
Photoproduction evidence for and against hidden-strangeness states near 2 GeV
Experimental evidence from coherent diffractive proton scattering has been
reported for two narrow baryonic resonances which decay predominantly to
strange particles. These states, with masses close to 2.0 GeV would, if
confirmed, be candidates for hidden strangeness states with unusual internal
structure. In this paper we examine the literature on strangeness
photoproduction, to seek additional evidence for or against these states. We
find that one state is not confirmed, while for the other state there is some
mild supporting evidence favoring its existence. New experiments are called
for, and the expected photoproduction lineshapes are calculated.Comment: 9 pages, RevTex, five postscript figures, submitted to PR
Do weak institutions prolong crises? : On the identification, characteristics, and duration of declines during economic slumps
This working paper is part of the research programme on ‘Institutions, Governance and Long‐term Economic Growth’, a partnership between the French Development Agency (AFD) and the Maastricht Graduate School of Governance (Maastricht University - UNU-Merit). The research builds on the Institutional Profiles Database IPD, jointly developed by AFD and the French Ministry of the Economy since 2001
Extended Supersymmetries and the Dirac Operator
We consider supersymmetric quantum mechanical systems in arbitrary dimensions
on curved spaces with nontrivial gauge fields. The square of the Dirac operator
serves as Hamiltonian. We derive a relation between the number of supercharges
that exist and restrictions on the geometry of the underlying spaces as well as
the admissible gauge field configurations. From the superalgebra with two or
more real supercharges we infer the existence of integrability conditions and
obtain a corresponding superpotential. This potential can be used to deform the
supercharges and to determine zero modes of the Dirac operator. The general
results are applied to the Kahler spaces CP^n.Comment: 22 pages, no figure
The XX--model with boundaries. Part I: Diagonalization of the finite chain
This is the first of three papers dealing with the XX finite quantum chain
with arbitrary, not necessarily hermitian, boundary terms. This extends
previous work where the periodic or diagonal boundary terms were considered. In
order to find the spectrum and wave-functions an auxiliary quantum chain is
examined which is quadratic in fermionic creation and annihilation operators
and hence diagonalizable. The secular equation is in general complicated but
several cases were found when it can be solved analytically. For these cases
the ground-state energies are given. The appearance of boundary states is also
discussed and in view to the applications considered in the next papers, the
one and two-point functions are expressed in terms of Pfaffians.Comment: 56 pages, LaTeX, some minor correction
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