51,529 research outputs found
Sphaleron transition rate in the classical 1+1 dimensional abelian Higgs model at finite temperature
We compute the sphaleron transition rate in the 1+1 dimensional abelian Higgs
model at finite temperature, by real time simulation using the classical
canonical ensemble.Comment: 3 pages to appear in the Proceedings of Lattice '93, Dallas, Texas,
12-16 October 1993, comes as a single postscript file (LaTeX source available
from the authors), ITFA 93-3
Energy levels of a parabolically confined quantum dot in the presence of spin-orbit interaction
We present a theoretical study of the energy levels in a parabolically
confined quantum dot in the presence of the Rashba spin-orbit interaction
(SOI). The features of some low-lying states in various strengths of the SOI
are examined at finite magnetic fields. The presence of a magnetic field
enhances the possibility of the spin polarization and the SOI leads to
different energy dependence on magnetic fields applied. Furthermore, in high
magnetic fields, the spectra of low-lying states show basic features of
Fock-Darwin levels as well as Landau levels.Comment: 6 pages, 4 figures, accepted by J. Appl. Phy
Optical properties of Si/Si0.87Ge0.13 multiple quantum well wires
Nanometer-scale wires cut into a Si/Si0.87Ge0.13 multiple quantum well structure were fabricated and characterized by using photoluminescence and photoreflectance at temperatures between 4 and 20 K. It was found that, in addition to a low-energy broadband emission at around 0.8 eV and other features normally observable in photoluminescence measurements, fabrication process induced strain relaxation and enhanced electron-hole droplets emission together with a new feature at 1.131 eV at 4 K were observed. The latter was further identified as a transition related to impurities located at the Si/Si0.87Ge0.13 heterointerfaces
Data Unfolding with Wiener-SVD Method
Data unfolding is a common analysis technique used in HEP data analysis.
Inspired by the deconvolution technique in the digital signal processing, a new
unfolding technique based on the SVD technique and the well-known Wiener filter
is introduced. The Wiener-SVD unfolding approach achieves the unfolding by
maximizing the signal to noise ratios in the effective frequency domain given
expectations of signal and noise and is free from regularization parameter.
Through a couple examples, the pros and cons of the Wiener-SVD approach as well
as the nature of the unfolded results are discussed.Comment: 26 pages, 12 figures, match the accepted version by JINS
Indirect exchange of magnetic impurities in zigzag graphene ribbon
We use quantum Monte Carlo method to study the indirect coupling between two
magnetic impurities on the zigzag edge of graphene ribbon, with respect to the
chemical potential . We find that the spin-spin correlation between two
adatoms located on the nearest sites in the zigzag edge are drastically
suppressed around the zero-energy. As we switch the system away from
half-filling, the antiferromagnetic correlation is first enhanced and then
decreased. If the two adatoms are adsorbed on the sites belonging to the same
sublattice, we find similar behavior of spin-spin correlation except for a
crossover from ferromagnetic to antiferromagentic correlation in the vicinity
of zero-energy. We also calculated the weight of different components of
d-electron wave function and local magnet moment for various values of
parameters, and all the results are consistent with those of spin-spin
correlation between two magnetic impurities.Comment: 3 pages, 4 figures, conference proceedin
Generalized linear isotherm regularity equation of state applied to metals
A three-parameter equation of state (EOS) without physically incorrect
oscillations is proposed based on the generalized Lennard-Jones (GLJ) potential
and the approach in developing linear isotherm regularity (LIR) EOS of Parsafar
and Mason [J. Phys. Chem., 1994, 49, 3049]. The proposed (GLIR) EOS can include
the LIR EOS therein as a special case. The three-parameter GLIR, Parsafar and
Mason (PM) [Phys. Rev. B, 1994, 49, 3049], Shanker, Singh and Kushwah (SSK)
[Physica B, 1997, 229, 419], Parsafar, Spohr and Patey (PSP) [J. Phys. Chem. B,
2009, 113, 11980], and reformulated PM and SSK EOSs are applied to 30 metallic
solids within wide pressure ranges. It is shown that the PM, PMR and PSP EOSs
for most solids, and the SSK and SSKR EOSs for several solids, have physically
incorrect turning points, and pressure becomes negative at high enough
pressure. The GLIR EOS is capable not only of overcoming the problem existing
in other five EOSs where the pressure becomes negative at high pressure, but
also gives results superior to other EOSs.Comment: 9 pages, 3 figure
- …