Synthetic Topological Degeneracy by Anyon Condensation

Topological degeneracy is the degeneracy of the ground states in a many-body system in the large-system-size limit. Topological degeneracy cannot be lifted by any local perturbation of the Hamiltonian. 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 paper, we study a new type of topological degeneracy induced by condensing anyons along a line in 2D topological ordered states. Such topological degeneracy can be viewed as carried by each end of the line-defect, which is a generalization of Majorana zero-modes. The topological degeneracy can be used as a quantum memory. The ends of line-defects carry projective non-Abelian statistics, and braiding them allow us to perform fault tolerant quantum computations.Comment: 4 pages + references + 3 pages of supplementary material, 2 figures. reference update

Scheme for preparation of W state via cavity QED

In this paper, we presented a physical scheme to generate the multi-cavity maximally entangled W state via cavity QED. All the operations needed in this scheme are to modulate the interaction time only once.Comment: 8 pages, 1 figur

QCD corrections to the R-parity violating processes ppˉ/pp→eμ+Xp\bar{p}/pp \to e\mu+X at hadron colliders

We present the QCD corrections to the processes $p\bar{p}/pp \to e\mu+X$ at the Tevatron and the CERN large hadron collider(LHC). The numerical results show that variation of K factor is in the range between $1.28(1.32)$ and $1.79(1.58)$ at the Tevatron(LHC). We find that the QCD correction part from the one-loop gluon-gluon fusion subprocess is remarkable at the LHC and should be taken into account.Comment: 7 pages, 6 Postscript figures, to be appeared in Phy. Rev.