Tuesday, July 9, 2013

1307.1781 (Archak Purkayastha et al.)

Block entanglement of the Gutzwiller state and metal-insulator
transition in nanochains

Archak Purkayastha, V. Subrahmanyam
The block entanglement entropy is investigated in the Gutzwiller state as a function of the correlation projection parameter. A chain of $N$ sites is partitioned into two equal blocks. The entanglement entropy follows the conformal field theory (CFT) prediction of a logarithmic divergence with the size of the block in both the insulating limit (g=0) with central charge c=1, and the metallic limit (g=1) with c=2. In the metal-insulator crossover regime, it deviates from the CFT result. A scaling form is proposed that gives a good data collapse, exhibiting a metal-insulator crossover at g*N^(1/3) ~ 0.24. The entanglement spectrum also shows noticeable deviation, from the CFT prediction, in the crossover regime, thus it can also track a metal-insulator transition. The spacing distribution of the eigenvalues of the block reduced density matrix is investigated as a function of g, and is seen to exhibit a weak signature of the metal-insulator crossover. These results compare well with recent experiments on metal-insulator transitions in Ni nanochains.
View original: http://arxiv.org/abs/1307.1781

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