119262048
Z2fractionalized Chern/topological insulators in an exactly soluble correlated model
In this paper we propose an exactly soluble model in two-dimensional honeycomb lattice, from which two phases are found. One is the usual Chern/topological insulating state and the other is an interesting $Z_2$ fractionalized Chern/topological insulator. While their bulk properties are similar, the edge-states of physical electrons are quite different. The single electron excitation of the former shows a free particle-like behavior while the latter one is gapped, which provides a definite signature to identify the fractionalized states. The transition between these two phases is found to fall into the 3D Ising universal class. Significantly, near the quantum transition point the physical electron in the edge-states shows strong Luttinger liquid behavior. An extension to the interesting case of the square lattice is also made. In addition, we also discuss some relationship between our exactly soluble model and various Hubbard-like models existing in the literature. The essential difference between the proposed $Z_{2}$ fractionalized Chern insulator and the hotly pursued fractional Chern insulator is also pointed out. The present work may be helpful for further study on the fractionalized insulating phase and related novel correlated quantum phases.
18062907
Damping of collective nuclear motion and thermodynamic properties of nuclei beyond mean field
Abstract The dynamical description of correlated nuclear motion is based on a set of coupled equations of motion for the one-body density matrix ϱ (11′; t ) and the two-body correlation function c 2 (12, 1′2′; t ), which is obtained from the density-matrix hierarchy beyond conventional mean-field approaches by truncating three-body correlations. The resulting equations non-perturbatively describe particle-particle collisions (short-range correlations) as well as particle-hole interactions (long-range correlations). Within a basis of time-dependent Hartree-Fock states these equations of motion are solved for collective vibrations of 40 Ca at several finite thermal excitation energies corresponding to temperatures T = 0 – 6 MeV. Transport coefficients for friction and diffusion are extracted from the explicit solutions in comparison to the solutions of the associated TDHF, VUU, Vlasov or damped quantum oscillator equations of motion. We find that the actual magnitude of the transport coefficients is strongly influenced by particle-hole correlations at low temperature which generate large fluctuations in the nuclear shape degrees of freedom. Thermodynamically, the specific heat and the entropy of the system as a function of temperature does not differ much from the mean-field limit except for a bump in the specific heat around T ⋍ MeV which we attribute to the melting of shell effects in the correlated system.
119114164
A note on path integral formulism of Z2 slave-spin representation of Hubbard model
(4)where a ferromagnetic coupling J > 0 is assumed and Krepresents the the transverse external ﬁeld.At ﬁrst sight, one may directly use the coherent stateof spin operator in constructing the path integral rep-resentation, (One can ﬁnd a brief but useful introduc-tion to this issue in Ref. 9.) however, this will lead toan extra topological Berry phase term and is not easyto utilize practically. An alterative approach is to usethe eigenstates of spin operator τ
121072448
On the Nonautonomous Nonlinear Schrödinger Equations and Soliton Management
We present some novel results on the nonlinear Schrodinger equations with time‐ and space‐dependent dispersion, nonlinearity, dissipation/gain and external potentials which read i∂u(x,t)∂t+f(x,t)∂2u(x,t)∂x2+g(x,t)|u(x,t)|2u(x,t)+V(x,t)u(x,t)+iγ(x,t)u(x,t) = 0. Based on these results, we show some explicit ways to control the soliton dynamics in some physically interesting nonlinear systems like Bose‐Einstein condensates and optical soliton transmission.
118605638
Subleading soft behavior of QCD amplitudes
We elaborate on the radiative behaviour of tree-level scattering amplitudes in the soft regime. We show that the sub-leading soft term in single-gluon emission of quark-gluon amplitudes in QCD is controlled by differential operators, whose universal form can be derived from both on-shell recursion relation and gauge invariance, as it was shown to hold for graviton- and gluon-scattering.