10,543 research outputs found
Comment on "Phase separation in a two-species Bose mixture"
In an article in 2007, Mishra, Pai, and Das [Phys. Rev. A 76, 013604 (2007)]
investigated the two-component Bose-Hubbard model using the numerical DMRG
procedure. In the regime of inter-species repulsion larger than the
intra-species repulsion , they found a transition from a uniform miscible
phase to phase-separation occurring at a finite value of , e.g., at around
for and . In
this comment, we show that this result is not correct and in fact the
two-component Bose-Hubbard model is unstable to phase-separation for any
.Comment: 2 pages, 3 figures, submitted to Phys. Rev.
Recommended from our members
On defining partition entropy by inequalities
Partition entropy is the numerical metric of uncertainty within
a partition of a finite set, while conditional entropy measures the degree of
difficulty in predicting a decision partition when a condition partition is
provided. Since two direct methods exist for defining conditional entropy
based on its partition entropy, the inequality postulates of monotonicity,
which conditional entropy satisfies, are actually additional constraints on
its entropy. Thus, in this paper partition entropy is defined as a function
of probability distribution, satisfying all the inequalities of not only partition
entropy itself but also its conditional counterpart. These inequality
postulates formalize the intuitive understandings of uncertainty contained
in partitions of finite sets.We study the relationships between these inequalities,
and reduce the redundancies among them. According to two different
definitions of conditional entropy from its partition entropy, the convenient
and unified checking conditions for any partition entropy are presented, respectively.
These properties generalize and illuminate the common nature
of all partition entropies
Equivalence of Two Approaches for Quantum-Classical Hybrid Systems
We discuss two approaches that are used frequently to describe
quantum-classical hybrid system. One is the well-known mean-field theory and
the other adopts a set of hybrid brackets which is a mixture of quantum
commutators and classical Poisson brackets. We prove that these two approaches
are equivalent.Comment: 9 page
The Miscible-Immiscible Quantum Phase Transition in Coupled Two-Component Bose-Einstein Condensates in 1D Optical Lattices
Using numerical techniques, we study the miscible-immiscible quantum phase
transition in a linearly coupled binary Bose-Hubbard model Hamiltonian that can
describe low-energy properties of a two-component Bose-Einstein condensate in
optical lattices. With the quantum many-body ground state obtained from density
matrix renormalization group algorithm, we calculate the characteristic
physical quantities of the phase transition controlled by the linear coupling
between two components. Furthermore we calculate the Binder cumulant to
determine the critical point and draw the phase diagram. The strong-coupling
expansion shows that in the Mott insulator regime the model Hamiltonian can be
mapped to a spin 1/2 XXZ model with a transverse magnetic field.Comment: 10 pages, 10 figures, submitted to Phys. Rev.
Many-body dynamics of a Bose system with attractive interactions on a ring
We investigate the many-body dynamics of an effectively attractive
one-dimensional Bose system confined in a toroidal trap. The mean-field theory
predicts that a bright-soliton state will be formed when increasing the
interparticle interaction over a critical point. The study of quantum many-body
dynamics in this paper reveals that there is a modulation instability in a
finite Bose system correspondingly. We show that Shannon entropy becomes
irregular near and above the critical point due to quantum correlations. We
also study the dynamical behavior of the instability by exploring the momentum
distribution and the fringe visibility, which can be verified experimentally by
releasing the trapComment: 6 pages,5 figure
microRNA expression in peripheral blood cells following acute ischemic stroke and their predicted gene targets.
BackgroundmicroRNA (miRNA) are important regulators of gene expression. In patients with ischemic stroke we have previously shown that differences in immune cell gene expression are present. In this study we sought to determine the miRNA that are differentially expressed in peripheral blood cells of patients with acute ischemic stroke and thus may regulate immune cell gene expression.MethodsmiRNA from peripheral blood cells of forty-eight patients with ischemic stroke and vascular risk factor controls were compared. Differentially expressed miRNA in patients with ischemic stroke were determined by microarray with qRT-PCR confirmation. The gene targets and pathways associated with ischemic stroke that may be regulated by the identified miRNA were characterized.ResultsIn patients with acute ischemic stroke, miR-122, miR-148a, let-7i, miR-19a, miR-320d, miR-4429 were decreased and miR-363, miR-487b were increased compared to vascular risk factor controls. These miRNA are predicted to regulate several genes in pathways previously identified by gene expression analyses, including toll-like receptor signaling, NF-κβ signaling, leukocyte extravasation signaling, and the prothrombin activation pathway.ConclusionsSeveral miRNA are differentially expressed in blood cells of patients with acute ischemic stroke. These miRNA may regulate leukocyte gene expression in ischemic stroke including pathways involved in immune activation, leukocyte extravasation and thrombosis
- …