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Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
Exact and numerical results for a dimerized coupled spin- 1/2 chain
1School of Natural Sciences, Institute for Advanced Study, Olden Lane, Princeton, New Jersey 08540 and Departamento de Fisica, Universidade Federal de Sao Carlos, Caixa Postal 676, 13565-905, Sao Carlos, Brazil.
Abstract:
We establish exact results for coupled spin-1/2 chains for special values of the four-spin interaction V and dimerization parameter delta. The first exact result is at delta = 1/2 and V = -2. Because we find a very small but finite gap in this dimerized chain, this can serve as a very strong test case for numerical and approximate analytical techniques. The second result is for the homogeneous chain with V = -4 and gives evidence that the system has a spontaneously dimerized ground state. Numerical diagonalization and bosonization techniques indicate that the interplay between dimerization and interaction could result in gapless phases in the regime 0=V<-2.
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