4,892 research outputs found
Supersymmetry and the Chiral Schwinger Model
We have constructed the N=1/2 supersymmetric general Abelian model with
asymmetric chiral couplings. This leads to a N=1/2 supersymmetrization of the
Schwinger model. We show that the supersymmetric general model is plagued with
problems of infrared divergence. Only the supersymmetric chiral Schwinger model
is free from such problems and is dynamically equivalent to the chiral
Schwinger model because of the peculiar structure of the N=1/2 multiplets.Comment: one 9 pages Latex file, one ps file with one figur
Quantification of finite-temperature effects on adsorption geometries of -conjugated molecules
The adsorption structure of the molecular switch azobenzene on Ag(111) is
investigated by a combination of normal incidence x-ray standing waves and
dispersion-corrected density functional theory. The inclusion of non-local
collective substrate response (screening) in the dispersion correction improves
the description of dense monolayers of azobenzene, which exhibit a substantial
torsion of the molecule. Nevertheless, for a quantitative agreement with
experiment explicit consideration of the effect of vibrational mode
anharmonicity on the adsorption geometry is crucial.Comment: 12 pages, 3 figure
Thermodynamics of Relativistic Fermions with Chern-Simons Coupling
We study the thermodynamics of the relativistic Quantum Field Theory of
massive fermions in three space-time dimensions coupled to an Abelian
Maxwell-Chern-Simons gauge field. We evaluate the specific heat at finite
temperature and density and find that the variation with the statistical angle
is consistent with the non-relativistic ideas on generalized statistics.Comment: 12 pages, REVTe
Chiral three-nucleon forces and bound excited states in neutron-rich oxygen isotopes
We study the spectra of neutron-rich oxygen isotopes based on chiral two- and
three-nucleon interactions. First, we benchmark our many-body approach by
comparing ground-state energies to coupled-cluster results for the same
two-nucleon interaction, with overall good agreement. We then calculate bound
excited states in 21,22,23O, focusing on the role of three-nucleon forces, in
the standard sd shell and an extended sdf7/2p3/2 valence space. Chiral
three-nucleon forces provide important one- and two-body contributions between
valence neutrons. We find that both these contributions and an extended valence
space are necessary to reproduce key signatures of novel shell evolution, such
as the N = 14 magic number and the low-lying states in 21O and 23O, which are
too compressed with two-nucleon interactions only. For the extended space
calculations, this presents first work based on nuclear forces without
adjustments. Future work is needed and open questions are discussed.Comment: 6 pages, 4 figures, published versio
On Aharonov-Casher bound states
In this work bound states for the Aharonov-Casher problem are considered.
According to Hagen's work on the exact equivalence between spin-1/2
Aharonov-Bohm and Aharonov-Casher effects, is known that the
term cannot be neglected in the
Hamiltonian if the spin of particle is considered. This term leads to the
existence of a singular potential at the origin. By modeling the problem by
boundary conditions at the origin which arises by the self-adjoint extension of
the Hamiltonian, we derive for the first time an expression for the bound state
energy of the Aharonov-Casher problem. As an application, we consider the
Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the
expression for the harmonic oscillator energies and compare it with the
expression obtained in the case without singularity. At the end, an approach
for determination of the self-adjoint extension parameter is given. In our
approach, the parameter is obtained essentially in terms of physics of the
problem.Comment: 11 pages, matches published versio
Anyonic physical observables and spin phase transition
The quantization of charged matter system coupled to Chern-Simons gauge
fields is analyzed in a covariant gauge fixing, and gauge invariant physical
anyon operators satisfying fractional statistics are constructed in a symmetric
phase, based on Dirac's recipe performed on QED. This method provides us a
definite way of identifying physical spectrums free from gauge ambiguity and
constructing physical anyon operators under a covariant gauge fixing. We then
analyze the statistical spin phase transition in a symmetry-broken phase and
show that the Higgs mechanism transmutes an anyon satisfying fractional
statistics into a canonical boson, a spin 0 Higgs boson or a topologically
massive photon.Comment: 14 pages, added references, a few improvement
Ab-initio calculation of the binding energy with the Hybrid Multideterminant scheme
We perform an ab-initio calculation for the binding energy of using
the CD-Bonn 2000 NN potential renormalized with the Lee-Suzuki method. The
many-body approach to the problem is the Hybrid Multideterminant method. The
results indicate a binding energy of about , within a few hundreds KeV
uncertainty. The center of mass diagnostics are also discussed.Comment: 18 pages with 3 figures. More calculations added, to be published in
EPJ
- …