Mesozoic magmatism in Tengchong block, Southeastern Tibet, and its tectonic implications

Abstract HKT-ISTP 2013 A

Experimental signatures of 3d fractional topological insulators

In this work we explore experimental signatures of fractional topological insulators in three dimensions. These are states of matter with a fully gapped bulk that host exotic gapless surface states and fractionally charged quasiparticles. They are partially characterized by a non-trivial magneto-electric response while preserving time reversal. We describe how these phases appear in a variety of probes including photoemmission, tunneling, and quantum oscillations. We also discuss the effects of doping and proximate superconductivity. We argue that despite our current theoretical inability to predict materials where such phases will realized, they should be relatively easy to detect experimentally.Comment: 6 pages, 1 figur

Fault Inductance Based Protection for DC Distribution Systems

The fault protection is a critical element to ensure the reliable and secure operation of DC distribution systems. Most DC distribution systems are tightly coupled systems with low line impedances which may result in fast current increase during a fault. Thus, it is challenging to develop a fast and reliable DC fault protection method. This paper proposes and develops a novel fault inductance based DC protection method without communication between protection units at different locations. The performance of the developed protection algorithm was validated in a Real-Time Hardware-In-the-Loop (RTHIL) test platform. The testing results indicate that the developed inductance based fault location algorithm detects and locates faults with fast speed and high accuracy. Preliminary sensitivity analysis on measurement errors are also conducted to study impacts on accuracy of estimated fault inductance.Center for Electromechanic

Microscopic origin of local moments in a zinc-doped high-TcT_{c} superconductor

The formation of a local moment around a zinc impurity in the high-$T_{c}$ cuprate superconductors is studied within the framework of the bosonic resonating-valence-bond (RVB) description of the $t-J$ model. A topological origin of the local moment has been shown based on the phase string effect in the bosonic RVB theory. It is found that such an $S=1/2$ moment distributes near the zinc in a form of staggered magnetic moments at the copper sites. The corresponding magnetic properties, including NMR spin relaxation rate, uniform spin susceptibility, and dynamic spin susceptibility, etc., calculated based on the theory, are consistent with the experimental measurements. Our work suggests that the zinc substitution in the cuprates provide an important experimental evidence for the RVB nature of local physics in the original (zinc free) state.Comment: The topological reason of local moment formation is given. One figure is adde

A new class of (2+1)(2+1)-d topological superconductor with Z8\mathbb{Z}_8 topological classification

The classification of topological states of matter depends on spatial dimension and symmetry class. For non-interacting topological insulators and superconductors the topological classification is obtained systematically and nontrivial topological insulators are classified by either integer or $Z_2$. The classification of interacting topological states of matter is much more complicated and only special cases are understood. In this paper we study a new class of topological superconductors in $(2+1)$ dimensions which has time-reversal symmetry and a $\mathbb{Z}_2$ spin conservation symmetry. We demonstrate that the superconductors in this class is classified by $\mathbb{Z}_8$ when electron interaction is considered, while the classification is $\mathbb{Z}$ without interaction.Comment: 5 pages main text and 3 pages appendix. 1 figur

Topological aspect of graphene physics

Topological aspects of graphene are reviewed focusing on the massless Dirac fermions with/without magnetic field. Doubled Dirac cones of graphene are topologically protected by the chiral symmetry. The quantum Hall effect of the graphene is described by the Berry connection of a manybody state by the filled Landau levels which naturally possesses non-Abelian gauge structures. A generic principle of the topologically non trivial states as the bulk-edge correspondence is applied for graphene with/without magnetic field and explain some of the characteristic boundary phenomena of graphene.Comment: 12 pages, 8 figures. Proceedings for HMF-1