7,255 research outputs found
Massive Overlap Fermions on Anisotropic Lattices
We formulate the massive overlap fermions on anisotropic lattices.
We find that the dispersion relation for the overlap fermion resembles the
continuum form in the low-momentum region once the bare parameters are properly
tuned. The quark self-energy and the quark field renormalization constants are
calculated to one-loop in bare lattice perturbation theory.
We argue that massive domain wall quarks might be helpful in lattice QCD
studies on heavy-light hadron spectroscopy.Comment: 21 pages, 5 figures, one reference added compared with v.
Localization of fermionic fields on braneworlds with bulk tachyon matter
Recently, Pal and Skar in [arXiv:hep-th/0701266] proposed a mechanism to
arise the warped braneworld models from bulk tachyon matter, which are endowed
with a thin brane and a thick brane. In this framework, we investigate
localization of fermionic fields on these branes. As in the 1/2 spin case, the
field can be localized on both the thin and thick branes with inclusion of
scalar background. In the 3/2 spin extension, the general supergravity action
coupled to chiral supermultiplets is considered to produce the localization on
both the branes as a result.Comment: 9 pages, no figure
Gauged Q ball in a piecewise parabolic potential
Q ball solutions are considered within the theory of a complex scalar field
with a gauged
U(1) symmetry and a parabolic-type potential. In the thin-walled limit, we
show explicitly that there is a maximum size for these objects because of the
repulsive Coulomb force. The size of Q ball will increase with the decrease of
local minimum of the potential. And when the two minima degenerate, the energy
stored within the surface of the Q ball becomes significant.
Furthermore, we find an analytic expression for gauged Q ball, which is
beyond the conventional thin-walled limit.Comment: 1 figure
Reconstruction of Cosmological Models From Equation of State of Dark Energy
We consider a class of five-dimensional cosmological solutions which contains
two arbitrary function and . We found that the arbitrary
function contained in the solutions can be rewritten in terms of the
redshift as a new arbitrary function . We further showed that this
new arbitrary function could be solved out for four known parameterized
equations of state of dark energy. Then the models can be reconstructed
and the evolution of the density and deceleration parameters of the universe
can be determined.Comment: 10 pages, 4 eps figures, ws-ijmpd.cls styl
Scaling of the CKM Matrix in the 5D MSSM
We discuss a five-dimensional Minimal Supersymmetric Standard Model
compactified on a orbifold, looking at, in particular, the one-loop
evolution equations of the Yukawa couplings for the quark sector and various
flavor observables. Different possibilities for the matter fields are
discussed, that is, where they are in the bulk or localised to the brane. The
two possibilities give rise to quite different behaviours. By studying the
implications of the evolution with the renormalisation group of the Yukawa
couplings and of the flavor observables we find that, for a theory that is
valid up to the unification scale, the case where fields are localised to the
brane, with a large , would be more easily distinguishable from
other scenarios.Comment: 12 pages, 8 figures, Extra comments adde
Method and System for Scatter Correction in X-Ray Imaging
Approaches for deriving scatter information using inverse tracking of scattered X-rays is disclosed. In certain embodiments scattered rays are tracked from respective locations on a detector to a source of the X-ray radiation, as opposed to tracking schemes that proceed from the source to the detector. In one such approach, the inverse tracking is implemented using a density integrated volume that reduces the integration steps performed
Counterdiabatic driving for pseudo- and antipseudo- Hermitian systems
In this work, we study the counterdiabatic driving scheme in pseudo- and
antipseudo- Hermitian systems. By discussing the adiabatic condition for
non-Hermitian system, we show that the adiabatic evolution of state can only be
realized in the non-Hermitian system which possesses real energy spectrum.
Therefore, the counterdiabatic driving scheme to reproduce an exact evolution
of an energy eigenstate needs either real energy spectrum or dropping its parts
of dynamic phase and Berry phase. In this sense, we derive the adiabatic
conditions and counterdiabatic driving Hamiltonians for the pseudo-Hermitian
Hamiltonian which possesses either real or complex energy spectrum and the
antipseudo-Hermitian Hamiltonian which possesses either imaginary or complex
energy spectrum. We also find the condition to get self-normalized energy
eigenstates in pseudo- and antipseudo- Hermitian system and derive the
well-defined population of bare states on this energy eigenstate. Our results
are illustrated by studying the counterdiabatic driving for a non-Hermitian
three level system, and a perfect population transfer with loss or gain is
realized.Comment: 9pages, 6figure
Electric field tunable multi-state tunnel magnetoresistances in 2D van der Waals magnetic heterojunctions
Magnetic tunnel junction (MTJ) based on van der Waals (vdW) magnetic layers
has been found to present excellent tunneling magnetoresistance (TMR) property,
which has great potential applications in field sensing, non-volatile magnetic
random access memories, and spin logics. Although MTJs composed of multilayer
vdW magnetic homojunctions have been extensively investigated, the ones
composed of vdW magnetic heterojunction is still to be explored. Here we use
first-principles approaches to reveal that the magnetic heterojunction MTJs
have much more distinguishable TMR values than the homojunction ones. In the
MTJ composed of bilayer CrI3/bilayer Cr2Ge2Te6 heterojunction, we find there
are eight stable magnetic states, leading to seven distinguishable electronic
resistances. As a result, six sizable TMRs larger than 600% can be obtained
(the maximum TMR is up to 120,000%). The number of distinguishable memories is
more than two times larger than that of a four-layered homojunction MTJ. The
underlying relationships among magnetic state, spin-polarized band structures,
and transmission spectrums are further revealed to explain the multiple TMR
values. We also find that the magnetic states and thus TMRs can be efficiently
modulated by an external electric field. This study opens an avenue to the
design of high-performance MTJ devices based on vdW heterojunctions.Comment: 6 figure
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