30,014 research outputs found
Quantum correlations in topological quantum phase transitions
We study the quantum correlations in a 2D system that possesses a topological
quantum phase transition. The quantumness of two-body correlations is measured
by quantum discord. We calculate both the correlation of two local spins and
that of an arbitrary spin with the rest of the lattice. It is notable that
local spins are classically correlated, while the quantum correlation is hidden
in the global lattice. This is different from other systems which are not
topologically orderd. Moreover, the mutual information and global quantum
discord show critical behavior in the topological quantum phase transition.Comment: 6 pages, 3 figure
Angular Momentum Distribution Function of the Laughlin Droplet
We have evaluated the angular-momentum distribution functions for finite
numbers of electrons in Laughlin states. For very small numbers of electrons
the angular-momentum state occupation numbers have been evaluated exactly while
for larger numbers of electrons they have been obtained from Monte-Carlo
estimates of the one-particle density matrix. An exact relationship, valid for
any number of electrons, has been derived for the ratio of the occupation
numbers of the two outermost orbitals of the Laughlin droplet and is used to
test the accuracy of the MC calculations. We compare the occupation numbers
near the outer edges of the droplets with predictions based on the chiral
Luttinger liquid picture of Laughlin state edges and discuss the surprisingly
large oscillations in occupation numbers which occur for angular momenta far
from the edge.Comment: 11 pages of RevTeX, 2 figures available on request. IUCM93-00
Modification of nucleon properties in nuclear matter and finite nuclei
We present a model for the description of nuclear matter and finite nuclei,
and at the same time, for the study of medium modifications of nucleon
properties. The nucleons are described as nontopological solitons which
interact through the self-consistent exchange of scalar and vector mesons. The
model explicitly incorporates quark degrees of freedom into nuclear many-body
systems and provides satisfactory results on the nuclear properties. The
present model predicts a significant increase of the nucleon radius at normal
nuclear matter density. It is very interesting to see the nucleon properties
change from the nuclear surface to the nuclear interior.Comment: 22 pages, 10 figure
Current and charge distributions of the fractional quantum Hall liquids with edges
An effective Chern-Simons theory for the quantum Hall states with edges is
studied by treating the edge and bulk properties in a unified fashion. An exact
steady-state solution is obtained for a half-plane geometry using the
Wiener-Hopf method. For a Hall bar with finite width, it is proved that the
charge and current distributions do not have a diverging singularity. It is
shown that there exists only a single mode even for the hierarchical states,
and the mode is not localized exponentially near the edges. Thus this result
differs from the edge picture in which electrons are treated as strictly one
dimensional chiral Luttinger liquids.Comment: 21 pages, REV TeX fil
Effects of momentum-dependent nuclear potential on two-nucleon correlation functions and light cluster production in intermediate energy heavy-ion collisions
Using an isospin- and momentum-dependent transport model, we study the
effects due to the momentum dependence of isoscalar nuclear potential as well
as that of symmetry potential on two-nucleon correlation functions and light
cluster production in intermediate energy heavy-ion collisions induced by
neutron-rich nuclei. It is found that both observables are affected
significantly by the momentum dependence of nuclear potential, leading to a
reduction of their sensitivity to the stiffness of nuclear symmetry energy.
However, the t/He ratio remains a sensitive probe of the density
dependence of nuclear symmetry energy.Comment: 20 pages, 11 figure
Binding Transition in Quantum Hall Edge States
We study a class of Abelian quantum Hall (QH) states which are topologically
unstable (T-unstable). We find that the T-unstable QH states can have a phase
transition on the edge which causes a binding between electrons and reduces the
number of gapless edge branches. After the binding transition, the
single-electron tunneling into the edge gains a finite energy gap, and only
certain multi-electron co-tunneling (such as three-electron co-tunneling for
edges) can be gapless. Similar phenomenon also appear for edge state
on the boundary between certain QH states. For example edge on the boundary
between and states only allow three-electron co-tunneling at
low energies after the binding transition.Comment: 4 pages, RevTeX, 1 figur
Absorption cross section in warped AdS_3 black hole revisited
We investigate the absorption cross section for minimal-coupled scalars in
the warped AdS_3 black hole. According to our calculation, the cross section
reduces to the horizon area in the low energy limit as usually expected in
contrast to what was previously found. We also calculate the greybody factor
and find that the effective temperatures for the two chiral CFT's are
consistent with that derived from the quasinormal modes. Observing the
conjectured warped AdS/CFT correspondence, we suspect that a specific sector of
the CFT operators with the desired conformal dimension could be responsible for
the peculiar thermal behaviour of the warped AdS_3 black hole.Comment: 16+1 pages, typos corrected, references and footnotes adde
Minimal Models for a Superconductor-Insulator Conformal Quantum Phase Transition
Conformal field theories do not only classify 2D classical critical behavior
but they also govern a certain class of 2D quantum critical behavior. In this
latter case it is the ground state wave functional of the quantum theory that
is conformally invariant, rather than the classical action. We show that the
superconducting-insulating (SI) quantum phase transition in 2D Josephson
junction arrays (JJAs) is a (doubled) Gaussian conformal quantum critical
point. The quantum action describing this system is a doubled
Maxwell-Chern-Simons model in the strong coupling limit. We also argue that the
SI quantum transitions in frustrated JJAs realize the other possible
universality classes of conformal quantum critical behavior, corresponding to
the unitary minimal models at central charge .Comment: 4 pages, no figure
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