Dresden 2011 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: TR: Quantum Coherence and Quantum Information Systems 1 (jointly with MA and HL)
TT 30.7: Talk
Wednesday, March 16, 2011, 12:15–12:30, HSZ 03
Edge State, Entanglement Entropy Spectra and Critical Anisotropic Honeycomb Lattice Hopping Coupling of — •Ming-Chiang Chung1,2, Yi-Hao Jhu3, Pochung Chen3, and Sungkit Yip2 — 1Physics Division, National Center for Theoretical Science, Hsinchu, 30013, Taiwan — 2Institute of Physics, Academia Sinica, Taipei 11529, Taiwan — 3Physics Department, National Tsing Hua University, Hsinchu, 30013, Taiwan
For a bipartite honeycomb lattice, we show that the Berry phase depends not only on the shape of the system but also on the hopping couplings. Using the entanglement entropy spectra obtained by diagonalizing the block Green’s function matrices, the maximal entangled state with the eigenvalue λm=1/2 of the reduced density matrix is shown to have one-to-one correspondence to the zero energy states of the lattice with open boundaries, which depends on the Berry phase. For the systems with finite bearded edges along x-direction we find critical hopping couplings: the maximal entangled states (zero-energy states) appear pair by pair if one increases the hopping coupling h over the critical couplings hcs.