6,293 research outputs found
Dynamically Spontaneous Symmetry Breaking and Masses of Lightest Nonet Scalar Mesons as Composite Higgs Bosons
Based on the (approximate) chiral symmetry of QCD Lagrangian and the bound
state assumption of effective meson fields, a nonlinearly realized effective
chiral Lagrangian for meson fields is obtained from integrating out the quark
fields by using the new finite regularization method. As the new method
preserves the symmetry principles of the original theory and meanwhile keeps
the finite quadratic term given by a physically meaningful characteristic
energy scale , it then leads to a dynamically spontaneous symmetry
breaking in the effective chiral field theory. The gap equations are obtained
as the conditions of minimal effective potential in the effective theory. The
instanton effects are included via the induced interactions discovered by 't
Hooft and found to play an important role in obtaining the physical solutions
for the gap equations. The lightest nonet scalar mesons(, ,
and ) appearing as the chiral partners of the nonet pseudoscalar mesons
are found to be composite Higgs bosons with masses below the chiral symmetry
breaking scale GeV. In particular, the mass of the
singlet scalar (or the ) is found to be MeV.Comment: 15 pages, Revtex, published version, Eur. Phys. J. C (2004) (DOI)
10.1140/epjcd/s2004-01-001-
Simulating Nanowires and Ultra-Thin Body Transistors using NEMO5 on nanoHUB.org
During the past twenty years, the most important aspects of semiconductor electronics have advanced into the nanometer range, resulting in exponential increases of microprocessor computing performance. As the size of electrical components continues to shrink, the cost of experimental research and industrial fabrication in this field has increased dramatically. Thus, the development of accurate nanoscale model simulations becomes necessary as a measure to decrease the high financial expenses of advancing semiconductor technology. This simulator supports atomistic modeling in order to provide an accurate description of the nanoscale devices, as current electrical components operate in the quantum regime and are affected by atomistic fluctuations in real world devices. Using the fifth edition of the Nanoelectronics Modeling engine, or NEMO5, developed in the iNEMO group of Purdue’s Network for Computational Nanotechnology department, the tool is capable of computing strain, phonon spectra, electronic band structures, and many other properties of semiconductor devices. The simulator utilizes effective mass approximations to calculate a device’s internal quantities, such as charge distribution and current densities. Real-space Schrodinger and Poisson equations are solved self-consistently using a 2-D finite difference grid to provide an electric potential map of the device or material being tested. This user-friendly simulation tool will allow students, teachers, and researchers to explore the properties of nanoscale transistors in a graphical manner. The simulator will be able to provide information such as quantum states, transport characteristics, and self-consistent potential densities in an aesthetic manner so that these concepts can be understood intuitively
One-loop Helicity Amplitudes for Top Quark Pair Production in Randall-Sundrum Model
In this paper, we show how to calculate analytically the one-loop helicity
amplitudes for the process induced by KK gluon,
using the spinor-helicity formalism. A minimal set of Feynman rules which are
uniquely fixed by gauge invariance and the color representation of the KK gluon
are derived and used in the calculation. Our results can be applied to a
variety of models containing a massive color octet vector boson.Comment: 37 pages, 10 figures, journal versio
CCD photometric study of the W UMa-type binary II CMa in the field of Berkeley 33
The CCD photometric data of the EW-type binary, II CMa, which is a contact
star in the field of the middle-aged open cluster Berkeley 33, are presented.
The complete R light curve was obtained. In the present paper, using the five
CCD epochs of light minimum (three of them are calculated from Mazur et al.
(1993)'s data and two from our new data), the orbital period P was revised to
0.22919704 days. The complete R light curve was analyzed by using the 2003
version of W-D (Wilson-Devinney) program. It is found that this is a contact
system with a mass ratio and a contact factor . The high mass
ratio () and the low contact factor () indicate that the system
just evolved into the marginal contact stage
Rechargeable Li/Cl battery down to -80 {\deg}C
Low temperature rechargeable batteries are important to life in cold
climates, polar/deep-sea expeditions and space explorations. Here, we report ~
3.5 - 4 V rechargeable lithium/chlorine (Li/Cl2) batteries operating down to
-80 {\deg}C, employing Li metal negative electrode, a novel CO2 activated
porous carbon (KJCO2) as the positive electrode, and a high ionic conductivity
(~ 5 to 20 mS cm-1 from -80 {\deg}C to 25 {\deg}C) electrolyte comprised of 1 M
aluminum chloride (AlCl3), 0.95 M lithium chloride (LiCl), and 0.05 M lithium
bis(fluorosulfonyl)imide (LiFSI) in low melting point (-104.5 {\deg}C) thionyl
chloride (SOCl2). Between room-temperature and -80 {\deg}C, the Li/Cl2 battery
delivered up to ~ 30,000 - 4,500 mAh g-1 first discharge capacity and a 1,200 -
5,000 mAh g-1 reversible capacity (discharge voltages in ~ 3.5 to 3.1 V) over
up to 130 charge-discharge cycles. Mass spectrometry and X-ray photoelectron
spectroscopy (XPS) probed Cl2 trapped in the porous carbon upon LiCl
electro-oxidation during charging. At lower temperature down to -80 {\deg}C,
SCl2/S2Cl2 and Cl2 generated by electro-oxidation in the charging step were
trapped in porous KJCO2 carbon, allowing for reversible reduction to afford a
high discharge voltage plateau near ~ 4 V with up to ~ 1000 mAh g-1 capacity
for SCl2/S2Cl2 reduction and up to ~ 4000 mAh g-1 capacity at ~ 3.1 V plateau
for Cl2 reduction. Towards practical use, we made CR2032 Li/Cl2 battery cells
to drive digital watches at -40 {\deg}C and light emitting diode at -80
{\deg}C, opening Li/Cl2 secondary batteries for ultra-cold conditions
Improving Sequence-to-Sequence Acoustic Modeling by Adding Text-Supervision
This paper presents methods of making using of text supervision to improve
the performance of sequence-to-sequence (seq2seq) voice conversion. Compared
with conventional frame-to-frame voice conversion approaches, the seq2seq
acoustic modeling method proposed in our previous work achieved higher
naturalness and similarity. In this paper, we further improve its performance
by utilizing the text transcriptions of parallel training data. First, a
multi-task learning structure is designed which adds auxiliary classifiers to
the middle layers of the seq2seq model and predicts linguistic labels as a
secondary task. Second, a data-augmentation method is proposed which utilizes
text alignment to produce extra parallel sequences for model training.
Experiments are conducted to evaluate our proposed method with training sets at
different sizes. Experimental results show that the multi-task learning with
linguistic labels is effective at reducing the errors of seq2seq voice
conversion. The data-augmentation method can further improve the performance of
seq2seq voice conversion when only 50 or 100 training utterances are available.Comment: 5 pages, 4 figures, 2 tables. Submitted to IEEE ICASSP 201
Indications of incommensurate spin fluctuations in doped triangular antiferromagnets
The incommensurate spin fluctuation of the doped triangular antiferromagnet
is studied within the t-J model. It is shown that the commensurate peak near
the half-filling is split into six incommensurate peaks in the underdoped and
optimally doped regimes. The incommensurability increases with the hole
concentration at lower dopings, and saturates at higher dopings. Although the
incommensurability is almost energy independent, the weight of these
incommensurate peaks decreases with energy and temperature.Comment: 5 pages, seven figures are include
Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries
We developed two-step solution-phase reactions to form hybrid materials of
Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion
battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over
free particle growth in solution allowed for the electrically insulating Mn3O4
nanoparticles wired up to a current collector through the underlying conducting
graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific
capacity up to ~900mAh/g near its theoretical capacity with good rate
capability and cycling stability, owing to the intimate interactions between
the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO
hybrid could be a promising candidate material for high-capacity, low-cost, and
environmentally friendly anode for lithium ion batteries. Our
growth-on-graphene approach should offer a new technique for design and
synthesis of battery electrodes based on highly insulating materials.Comment: JACS in pres
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