This series consists of talks in the area of Condensed Matter.
The density matrix renormalization group (DMRG), which
has proved so successful in one dimension, has been making the push into higher
dimensions, with the fractional quantum Hall (FQH) effect an important target.
I'll briefly explain how the infinite DMRG algorithm can be adapted to find the
degenerate ground states of a microscopic FQH Hamiltonian on an infinitely long
cylinder, then focus on two applications. To characterize the topological order
of the phase, I'll show that the bipartite entanglement spectrum of the ground
We have used a recently proposed quantum Monte Carlo
algorithm [1] to study spinons (emergent S = 1/2 excitations) in 2D
Resonating-Valence-Bond (RVB) spin liquids and in a J-Q model hosting a Neel –
Valence Bond Solid (VBS) phase transition at zero temperature [2]. We confirm
that spinons are well defined quasi-particles with finite intrinsic size in the
RVB spin liquid. The distance distribution between two spinons shows signatures
of deconfinement.
Two types of topological phases have attracted a lot of
attention in condensed matter physics:
symmetry protected
In this talk I will present our recent investigations on
possible topological phases in (111) heterostructures of transition metal
oxide. These (111) heterstructures are promising systems to realize many 2D
topological phases at high temperatures, even with strong correlations, which
is hard to be achieved in conventional materials.
Using quantum Monte Carlo simulations, we investigate the
finite-temperature phase diagram of hard-core bosons (XY model) in
Recent experiments in BEC
quantum magnets exhibit a dramatic evolution of
Topological phases are quantum
phases that can not be described by any local order parameter.
We study the spectrum of the amplitude mode, the analog
of the Higgs mode in high energy physics, for the d-density wave (DDW) state
proposed to describe the anomalous phenomenology of the pseudogap phase of the
high Tc cuprates. Even though the state breaks translational symmetry by a
lattice spacing and is described by a particle-hole singlet order parameter at
the wave vector q = Q = (pi, pi), remarkably, we find that the amplitude mode
spectrum can have peaks at both q = (0, 0) and q = Q = (pi , pi). In general,
The search for Majorana zero-modes in condensed matter
system has attract increasing research interests recently. Looking for Majorna
zero-mode is actually looking for topologically protected ground state
degeneracy. The topological degeneracies on closed manifolds have been used to
discover/define topological order in many-body systems, which contain
excitations with fractional statistics. In this talk, I will present our recent
work on new types of topological degeneracy induced by condensing anyons along
Near a critical
point, the equilibrium relaxation time of a system diverges and any change of control parameters leads to non-equilibrium behavior. The Kibble-Zurek (KZ) problem is to determine
the evolution of the system when the change is slow. In this talk, I will introduce a non-equilibrium scaling limit in which these evolutions are universal and define a KZ universality classification with exponents and scaling functions. I will illustrate the physics accessible in this