7,440 research outputs found
Exotic phase separation in one-dimensional hard-core boson system with two- and three-body interactions
We investigate the ground state phase diagram of hard-core boson system with
repulsive two-body and attractive three-body interactions in one-dimensional
optic lattice. When these two interactions are comparable and increasing the
hopping rate, physically intuitive analysis indicates that there exists an
exotic phase separation regime between the solid phase with charge density wave
order and superfluid phase. We identify these phases and phase transitions by
numerically analyzing the density distribution, structure factor of
density-density correlation function, three-body correlation function and von
Neumann entropy estimator obtained by density matrix renormalization group
method. These exotic phases and phase transitions are expected to be observed
in the ultra-cold polar molecule experiments by properly tuning interaction
parameters, which is constructive to understand the physics of ubiquitous
insulating-superconducting phase transitions in condensed matter systems
Global Structure of Exact Scalar Hairy Dynamical Black Holes
We study the global structure of some exact scalar hairy dynamical black
holes which were constructed in Einstein gravity either minimally or
non-minimally coupled to a scalar field. We find that both the apparent horizon
and the local event horizon (measured in luminosity coordinate) monotonically
increase with the advanced time as well as the Vaidya mass. At late advanced
times, the apparent horizon approaches the event horizon and gradually becomes
future outer. Correspondingly, the space-time arrives at stationary black hole
states with the relaxation time inversely proportional to the power
of the final black hole mass, where is the space-time dimension. These
results strongly support the solutions describing the formation of black holes
with scalar hair. We also obtain new charged dynamical solutions in the
non-minimal theory by introducing an Maxwell field which is non-minimally
coupled to the scalar.
The presence of the electric charge strongly modifies the dynamical evolution
of the space-time.Comment: 18 pages and 6 figures; minor corrections, publised versio
Criticality in Einstein-Gauss-Bonnet Gravity: Gravity without Graviton
General Einstein-Gauss-Bonnet gravity with a cosmological constant allows two
(A)dS spacetimes as its vacuum solutions. We find a critical point in the
parameter space where the two (A)dS spacetimes coalesce into one and the
linearized perturbations lack any bilinear kinetic terms. The vacuum
perturbations hence loose their interpretation as linear graviton modes at the
critical point. Nevertheless, the critical theory admits black hole solutions
due to the nonlinear effect. We also consider Einstein gravity extended with
general quadratic curvature invariants and obtain critical points where the
theory has no bilinear kinetic terms for either the scalar trace mode or the
transverse modes. Such critical phenomena are expected to occur frequently in
general higher derivative gravities.Comment: 21 pages, no figures;refereces adde
Self-overlap correction simplifies the Parisi formula for vector spins
We propose a simpler approach to identifying the limit of free energy in a
vector spin glass model by adding a self-overlap correction to the Hamiltonian.
This avoids constraining the self-overlap and allows us to identify the limit
with the classical Parisi formula, similar to the proof for scalar models with
Ising spins. For the upper bound, the correction cancels self-overlap terms in
Guerra's interpolation. For the lower bound, we add an extra perturbation term
to make the self-overlap concentrate, a technique already used in [16, 17] to
ensure the Ghirlanda-Guerra identities. We then remove the correction using a
Hamilton-Jacobi equation technique, which yields a formula similar to that in
[25]. Additionally, we sketch a direct proof of the main result in [18].Comment: 18 page
FDserver: A web service for protein folding research
*Summary:* To facilitate the study of protein folding, we have developed a web service for protein folding rate and folding type prediction as well as for the calculation of a variety of topological parameters of protein structure, which is freely available to the community.
*Availability:* http://sdbi.sdut.edu.cn/FDserve
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