14,664 research outputs found
Band structure renormalization and weak pseudogap behavior in Na_{0.33}CoO_2: Fluctuation exchange study based on a single band model
Based on a single band Hubbard model and the fluctuation exchange
approximation, the effective mass and the energy band renormalization in
NaCoO is elaborated. The renormalization is observed to exhibit
certain kind of anisotropy, which agrees qualitatively with the angle-resolved
photoemission spectroscopy (ARPES) measurements. Moreover, the spectral
function and density of states (DOS) in the normal state are calculated, with a
weak pseudogap behavior being seen, which is explained as a result of the
strong Coulomb correlations. Our results suggest that the large Fermi surface
(FS) associated with the band plays likely a central role in the
charge dynamics.Comment: 5 pages, 5 figure
One-pion exchange current corrections for nuclear magnetic moments in relativistic mean field theory
The one-pion exchange current corrections to isoscalar and isovector magnetic
moments of double-closed shell nuclei plus and minus one nucleon with
and 41 have been studied in the relativistic mean field (RMF)
theory and compared with previous relativistic and non-relativistic results. It
has been found that the one-pion exchange current gives a negligible
contribution to the isoscalar magnetic moments but a significant correction to
the isovector ones. However, the one-pion exchange current doesn't improve the
description of nuclear isovector magnetic moments for the concerned nuclei.Comment: 9 pages, 1 figure, 3 table
Dynamical decoupling of superconducting qubits
We show that two superconducting qubits interacting via a fixed transversal
coupling can be decoupled by appropriately-designed microwave feld excitations
applied to each qubit. This technique is useful for removing the effects of
spurious interactions in a quantum processor. We also simulate the case of a
qubit coupled to a two-level system (TLS) present in the insulating layer of
the Josephson junction of the qubit. Finally, we discuss the qubit-TLS problem
in the context of dispersive measurements, where the qubit is coupled to a
resonator.Comment: 4 figures, 6 page
Measurement-induced entanglement of two superconducting qubits
We study the problem of two superconducting quantum qubits coupled via a
resonator. If only one quanta is present in the system and the number of
photons in the resonator is measured with a null result, the qubits end up in
an entangled Bell state. Here we look at one source of errors in this quantum
nondemolition scheme due to the presence of more than one quanta in the
resonator, previous to the measurement. By analyzing the structure of the
conditional Hamiltonian with arbitrary number of quanta, we show that the
scheme is remarkably robust against these type of errors.Comment: 4 pages, 2 figure
Beads-on-String Model for Virtual Rectum Surgery Simulation
A beads-on-string model is proposed to handle the deformation and collision of the rectum in virtual surgery simulation. The idea is firstly inspired by the observation of the similarity in shape shared by a rectum with regular bulges and a string of beads. It is beneficial to introduce an additional layer of beads, which provides an interface to map the deformation of centreline to the associated mesh in an elegant manner and a bounding volume approximation in collision handling. Our approach is carefully crafted to achieve high computational efficiency and retain its physical basis. It can be implemented for real time surgery simulation application
Next-to-leading order QCD predictions for pair production of neutral Higgs bosons at the CERN Large Hadron Collider
We present the calculations of the complete NLO inclusive total cross
sections for pair production of neutral Higgs bosons through
annihilation in the minimal supersymmetric standard model at the CERN Large
Hadron Collider. In our calculations, we used both the DREG scheme and the DRED
scheme and found that the NLO total cross sections in the above two schemes are
the same. Our results show that the -annihilation contributions can
exceed ones of fusion and annihilation for ,
and productions when is large. In the case of , the
NLO corrections enhance the LO total cross sections significantly, which can
reach a few tens percent, while for , the corrections are relatively
small, and are negative in most parameter space. Moreover, the NLO QCD
corrections can reduce the dependence of the total cross sections on the
renormalization/factorization scale, especially for . We also use the
CTEQ6.1 PDF sets to estimate the uncertainty of LO and NLO total cross
sections, and find that the uncertainty arising from the choice of PDFs
increases with the increasing .Comment: 43 pages, 16 figures, minor changes, some references added, a version
to appear in PR
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