27,854 research outputs found
A geometric proof of the equality between entanglement and edge spectra
The bulk-edge correspondence for topological quantum liquids states that the
spectrum of the reduced density matrix of a large subregion reproduces the
thermal spectrum of a physical edge. This correspondence suggests an intricate
connection between ground state entanglement and physical edge dynamics. We
give a simple geometric proof of the bulk-edge correspondence for a wide
variety of physical systems. Our unified proof relies on geometric techniques
available in Lorentz invariant and conformally invariant quantum field
theories. These methods were originally developed in part to understand the
physics of black holes, and we now apply them to determine the local structure
of entanglement in quantum many-body systems.Comment: 7 pages, 3 figure
Bosonic model with fractionalization
Bosonic model with unfrustrated hopping and short-range repulsive interaction
is constructed that realizes fractionalized insulator phase in two
dimensions and in zero magnetic field. Such phase is characterized as having
gapped charged excitations that carry fractional electrical charge 1/3 and also
gapped vortices above the topologically ordered ground state.Comment: 7 pages, 3 figure
Deficiency of MecA in Streptococcus mutans causes major defects in cell envelope biogenesis, cell division, and biofilm formation
Light cone dynamics and reverse Kibble-Zurek mechanism in two-dimensional superfluids following a quantum quench
We study the dynamics of the relative phase of a bilayer of two-dimensional
superfluids after the two superfluids have been decoupled. We find that on
short time scales the relative phase shows "light cone" like dynamics and
creates a metastable superfluid state, which can be supercritical. We also
demonstrate similar light cone dynamics for the transverse field Ising model.
On longer time scales the supercritical state relaxes to a disordered state due
to dynamical vortex unbinding. This scenario of dynamically suppressed vortex
proliferation constitutes a reverse-Kibble-Zurek effect. We study this effect
both numerically using truncated Wigner approximation and analytically within a
newly suggested time dependent renormalization group approach (RG). In
particular, within RG we show that there are two possible fixed points for the
real time evolution corresponding to the superfluid and normal steady states.
So depending on the initial conditions and the microscopic parameters of the
Hamiltonian the system undergoes a non-equilibrium phase transition of the
Kosterlitz-Thouless type. The time scales for the vortex unbinding near the
critical point are exponentially divergent, similar to the equilibrium case.Comment: 14 pages, 10 figure
Weak coupling d-wave BCS superconductivity and unpaired electrons in overdoped La_{2-x}Sr_{x}CuO_{4} single crystals
The low-temperature specific heat (SH) of overdoped La_{2-x}Sr_{x}CuO_{4}
single crystals (0.178=<x=<0.290) has been measured. For the superconducting
samples (0.178=<x=<0.238), the derived gap values (without any adjusting
parameters) approach closely onto the theoretical prediction
\Delta_{0}=2.14k_{B}T_{c} for the weak-coupling d-wave BCS superconductivity.
In addition, the residual term \gamma(0) of SH at H=0 increases with x
dramatically when beyond x~0.22, and finally evolves into the value of a
complete normal metallic state at higher doping levels, indicating growing
amount of unpaired electrons. We argue that this large \gamma(0) cannot be
simply attributed to the pair breaking induced by the impurity scattering,
instead the phase separation is possible.Comment: 6 pages, 6 figures; Contents added; Accepted for publication in Phys.
Rev.
Quantum Hall Ferromagnets
It is pointed out recently that the quantum Hall states in bilayer
systems behave like easy plane quantum ferromagnets. We study the
magnetotransport of these systems using their ``ferromagnetic" properties and a
novel spin-charge relation of their excitations. The general transport is a
combination of the ususal Hall transport and a time dependent transport with
time average. The latter is due to a phase slippage process in
and is characterized by two topological constants. (Figures will be
provided upon requests).Comment: 4 pages, Revtex, Ohio State Universit
Vector meson - mixing and their form factors in light-cone quark model
The vector meson - mixing is studied in two alternative
scenarios with different numbers of mixing angles, i.e., the one-mixing-angle
scenario and the two-mixing-angle scenario, in both the octect-singlet mixing
scheme and the quark flavor mixing scheme. Concerning the reproduction of
experimental data and the behavior of transition form factors,
one-mixing-angle scenario in the quark flavor scheme performs better than that
in the octet-singlet scheme, while the two-mixing-angle scenario works well for
both mixing schemes. The difference between the two mixing angles in the
octet-singlet scheme is bigger than that in the quark flavor scheme.Comment: 16 pages, 7 figures, final version to appear in PR
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