95,199 research outputs found
Holographic non-relativistic fermionic fixed point and bulk dipole coupling
Inspired by the recently discovered non-relativistic fermionic fixed points,
we investigate how the presence of bulk dipole coupling modifies the spectral
function at one of these novel fixed points. As a result, although the infinite
flat band is always visible in the presence of the bulk dipole coupling as well
as chemical potential, the band is modified in a remarkable way at small
momenta up to the order of magnitude of bulk dipole coupling. On the other
hand, like a phoenix, a new Fermi surface sprouts from the formed gap when the
bulk dipole coupling is pushed up further such as to overshadow the charge
parameter, which is obviously different from what is found at the relativistic
fixed points.Comment: JHEP style, 1+17 pages, 9 figures, 1 table, typos corrected,
references added, version to appear in JHE
Block-block entanglement and quantum phase transitions in one-dimensional extended Hubbard model
In this paper, we study block-block entanglement in the ground state of
one-dimensional extended Hubbard model. Our results show that the phase diagram
derived from the block-block entanglement manifests richer structure than that
of the local (single site) entanglement because it comprises nonlocal
correlation. Besides phases characterized by the charge-density-wave, the
spin-density-wave, and phase-separation, which can be sketched out by the local
entanglement, singlet superconductivity phase could be identified on the
contour map of the block-block entanglement. Scaling analysis shows that behavior of the block-block entanglement may exist in both
non-critical and the critical regions, while some local extremum are induced by
the finite-size effect. We also study the block-block entanglement defined in
the momentum space and discuss its relation to the phase transition from
singlet superconducting state to the charge-density-wave state.Comment: 8 pages, 9 figure
Entanglement and quantum phase transition in the extended Hubbard model
We study quantum entanglement in one-dimensional correlated fermionic system.
Our results show, for the first time, that entanglement can be used to identify
quantum phase transitions in fermionic systems.Comment: 5 pages, 4 figure
Bott periodicity and stable quantum classes
We use Bott periodicity to relate previously defined quantum classes to
certain "exotic Chern classes" on . This provides an interesting
computational and theoretical framework for some Gromov-Witten invariants
connected with cohomological field theories. This framework has applications to
study of higher dimensional, Hamiltonian rigidity aspects of Hofer geometry of
, one of which we discuss here.Comment: prepublication versio
Desenvolvimento sustentável da Bacia Leiteira de Nossa Senhora da Glória no semi-árido sergipano.
Foram realizados dois encontros com técnicos e produtores para resgatar a história da Bacia Leiteira de Nossa Senhora da Glória e subsidiar o início dos trabalhos de rede de referência do Projeto Glória. Nos relatos e debates alguns temas foram amplamente discutidos: água, alimentação do gado, políticas públicas, mercado e agrotecnologia. Através das discussões pode-se concluir que é necessário um trabalho mais participativo para que técnicos e produtores encontrem tecnologias adequadas e se apropriem delas para alcançar a sustentabilidade da Bacia Leiteira de Nossa Senhora da Glória.1 CD-ROM
Cooper pairing near charged black holes
We show that a quartic contact interaction between charged fermions can lead
to Cooper pairing and a superconducting instability in the background of a
charged asymptotically Anti-de Sitter black hole. For a massless fermion we
obtain the zero mode analytically and compute the dependence of the critical
temperature T_c on the charge of the fermion. The instability we find occurs at
charges above a critical value, where the fermion dispersion relation near the
Fermi surface is linear. The critical temperature goes to zero as the marginal
Fermi liquid is approached, together with the density of states at the Fermi
surface. Besides the charge, the critical temperature is controlled by a four
point function of a fermionic operator in the dual strongly coupled field
theory.Comment: 1+33 pages, 4 figure
Black-hole dynamics in BHT massive gravity
Using an exact Vaidya-type null-dust solution, we study the area and entropy
laws for dynamical black holes defined by a future outer trapping horizon in
(2+1)-dimensional Bergshoeff-Hohm-Townsend (BHT) massive gravity. We consider
the theory admitting a degenerate (anti-)de Sitter vacuum and pure BHT gravity.
It is shown that, while the area of a black hole decreases by the injection of
a null dust with positive energy density in several cases, the Wald-Kodama
dynamical entropy always increases.Comment: 7 pages, 1 figur
Inclusive and Direct Photons in S + Au Central Collisions at 200A GeV/c
A hadron and string cascade model, JPCIAE, which is based on LUND string
model, PYTHIA event generator especially, is used to study both inclusive
photon production and direct photon production in 200A GeV S + Au central
collisions. The model takes into account the photon production from the
partonic QCD scattering process, the hadronic final-state interaction, and the
hadronic decay and deals with them consistently. The results of JPCIAE model
reproduce successfully both the WA93 data of low p_T inclusive photon
distribution and the WA80 data of transverse momentum dependent upper limit of
direct photon. The photon production from different decay channels is
investigated for both direct and inclusive photons. We have discussed the
effects of the partonic QCD scattering and the hadronic final-state interaction
on direct photon production as well.Comment: 6 pages with 5 figure
Plantio direto de milho consorciado com a gliricídia, na região agreste, com o uso de microtrator ou tração animal.
bitstream/item/145652/1/CT-76.pd
Holographic Superconductors with Power-Maxwell field
With the Sturm-Liouville analytical and numerical methods, we investigate the
behaviors of the holographic superconductors by introducing a complex charged
scalar field coupled with a Power-Maxwell field in the background of
-dimensional Schwarzschild AdS black hole. We note that the Power-Maxwell
field takes the special asymptotical solution near boundary which is different
from all known cases. We find that the larger power parameter for the
Power-Maxwell field makes it harder for the scalar hair to be condensated. We
also find that, for different , the critical exponent of the system is still
1/2, which seems to be an universal property for various nonlinear
electrodynamics if the scalar field takes the form of this paper.Comment: 14 pages, 1 figure, and 2 table
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