5,407 research outputs found
Factorization Breaking of for polarized deuteron targets in a relativistic framework
We discuss the possible factorization of the tensor asymmetry
measured for polarized deuteron targets within a relativistic framework. We
define a reduced asymmetry and find that factorization holds only in plane wave
impulse approximation and if p-waves are neglected. Our numerical results show
a strong factorization breaking once final state interactions are included. We
also compare the d-wave content of the wave functions with the size of the
factored, reduced asymmetry and find that there is no systematic relationship
of this quantity to the d-wave probability of the various wave functions
Quark-Hadron Duality
Quark-hadron duality and its potential applications are discussed. We focus
on theoretical efforts to model duality.Comment: Plenary Talk given at Baryons 2002, Newport News, VA, March 200
Interaction effects in a microscopic quantum wire model with strong spin-orbit interaction
We investigate the effect of strong interactions on the spectral properties
of quantum wires with strong Rashba spin-orbit interaction in a magnetic field,
using a combination of Matrix Product State and bosonization techniques.
Quantum wires with strong Rashba spin-orbit interaction and magnetic field
exhibit a partial gap in one-half of the conducting modes. Such systems have
attracted wide-spread experimental and theoretical attention due to their
unusual physical properties, among which are spin-dependent transport, or a
topological superconducting phase when under the proximity effect of an s-wave
superconductor. As a microscopic model for the quantum wire we study an
extended Hubbard model with spin-orbit interaction and Zeeman field. We obtain
spin resolved spectral densities from the real-time evolution of excitations,
and calculate the phase diagram. We find that interactions increase the pseudo
gap at and thus also enhance the Majorana-supporting phase and
stabilize the helical spin order. Furthermore, we calculate the optical
conductivity and compare it with the low energy spiral Luttinger Liquid result,
obtained from field theoretical calculations. With interactions, the optical
conductivity is dominated by an excotic excitation of a bound
soliton-antisoliton pair known as a breather state. We visualize the
oscillating motion of the breather state, which could provide the route to
their experimental detection in e.g. cold atom experiments
Slater-Pauling Rule and Curie-Temperature of Co-based Heusler compounds
A concept is presented serving to guide in the search for new materials with
high spin polarization. It is shown that the magnetic moment of half-metallic
ferromagnets can be calculated from the generalized Slater-Pauling rule.
Further, it was found empirically that the Curie temperature of Co based
Heusler compounds can be estimated from a seemingly linear dependence on the
magnetic moment. As a successful application of these simple rules, it was
found that CoFeSi is, actually, the half-metallic ferromagnet exhibiting
the highest magnetic moment and the highest Curie temperature measured for a
Heusler compound
Probing CP-violating Higgs contributions in gamma-gamma -> f anti-f through fermion polarization
We discuss the use of fermion polarization for studying neutral Higgs bosons
at a photon collider. To this aim we construct polarization asymmetries which
can isolate the contribution of a Higgs boson in , , from that of the QED continuum. This can help in getting
information on the coupling in case is a CP
eigenstate. We also construct CP-violating asymmetries which can probe CP
mixing in case has indeterminate CP. Furthermore, we take the MSSM with
CP violation as an example to demonstrate the potential of these asymmetries in
a numerical analysis. We find that these asymmetries are sensitive to the
presence of a Higgs boson as well as its CP properties over a wide range of
MSSM parameters. In particular, the method suggested can cover the region where
a light Higgs boson may have been missed by LEP due to CP violation in the
Higgs sector, and may be missed as well at the LHC.Comment: 14 pages, 14 figures, typeset in revtex4. Version which has appeared
in Physical Review D; typos in two references correcte
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