35,256 research outputs found
Muon anomaly and a lower bound on higgs mass due to a light stabilized radion in the Randall-Sundrum model
We investigate the Randall-Sundrum model with a light stabilized radion
(required to fix the size of the extra dimension) in the light of muon
anomalous magnetic moment . Using the recent data
(obtained from the E821 experiment of the BNL collaboration) which differs by
from the Standard Model result, we obtain constraints on radion
mass \mphi and radion vev \vphi. In the presence of a radion the beta
functions \beta(\l) and of higgs quartic coupling (\l) and
top-Yukawa coupling () gets modified. We find these modified beta
functions. Using these beta functions together with the anomaly constrained
\mphi and \vphi, we obtain lower bound on higgs mass . We compare our
result with the present LEP2 bound on .Comment: Version to be appeared in IJMP
Screening of charged impurities with multi-electron singlet-triplet spin qubits in quantum dots
Charged impurities in semiconductor quantum dots comprise one of the main
obstacles to achieving scalable fabrication and manipulation of singlet-triplet
spin qubits. We theoretically show that using dots that contain several
electrons each can help to overcome this problem through the screening of the
rough and noisy impurity potential by the excess electrons. We demonstrate how
the desired screening properties turn on as the number of electrons is
increased, and we characterize the properties of a double quantum dot
singlet-triplet qubit for small odd numbers of electrons per dot. We show that
the sensitivity of the multi-electron qubit to charge noise may be an order of
magnitude smaller than that of the two-electron qubit.Comment: 17 pages, 11 figures; typos corrected, minor revision
Path Integral Approach to Residual Gauge Fixing
In this paper we study the question of residual gauge fixing in the path
integral approach for a general class of axial-type gauges including the
light-cone gauge. We show that the two cases -- axial-type gauges and the
light-cone gauge -- lead to very different structures for the explicit forms of
the propagator. In the case of the axial-type gauges, fixing the residual
symmetry determines the propagator of the theory completely. On the other hand,
in the light-cone gauge there is still a prescription dependence even after
fixing the residual gauge symmetry, which is related to the existence of an
underlying global symmetry.Comment: revtex 13pages, slightly expanded discussion, version to be published
in Physical Review
Magnetic-field-induced chiral hidden order in URu2Si2
Two of the most striking and yet unresolved manifestations of the hidden
order (HO) in URu2Si2, are associated on one hand with the double-step
metamagnetic transitions and on the other with the giant anomalous Nernst
signal. Both are observed when a magnetic field is applied along the c-axis.
Here we provide for the first time a unified understanding of these puzzling
phenomena and the related field-temperature (B-T) phase diagram. We demonstrate
that the HO phase at finite fields can be explained with a chiral dxy+idx2-y2
spin density wave, assuming that the zero field HO contains only the
time-reversal symmetry preserving idx2-y2 component. We argue that the presence
of the field-induced chiral HO can be reflected in a distinctive non-linear
B-dependence of the Kerr angle, when a Kerr experiment is conducted for finite
fields. This fingerprint can be conclusive for the possible emergence of
chirality in the HO.Comment: 8 pages and 9 figures main text + 6 pages supplementary material.
Philosophical Magazine: Special Issue: Focused Issue on Hidden Order in
URu2Si2 (May 2014
Investigations on the usefulness of the Massively Parallel Processor for study of electronic properties of atomic and condensed matter systems
The usefulness of the Massively Parallel Processor (MPP) for investigation of electronic structures and hyperfine properties of atomic and condensed matter systems was explored. The major effort was directed towards the preparation of algorithms for parallelization of the computational procedure being used on serial computers for electronic structure calculations in condensed matter systems. Detailed descriptions of investigations and results are reported, including MPP adaptation of self-consistent charge extended Hueckel (SCCEH) procedure, MPP adaptation of the first-principles Hartree-Fock cluster procedure for electronic structures of large molecules and solid state systems, and MPP adaptation of the many-body procedure for atomic systems
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