Tetsuo Deguchi and Pijush K Ghosh 2009 J. Phys. A: Math. Theor. 42 475208 doi:10.1088/1751-8113/42/47/475208
Tetsuo Deguchi1 and Pijush K Ghosh2
Show affiliationsA non-Hermitian deformation of the one-dimensional transverse Ising model is shown to have the property of quasi-hermiticity. The transverse Ising chain is obtained from the starting non-Hermitian Hamiltonian through a similarity transformation. Consequently, both the models have identical eigen spectra, although the eigenfunctions are different. The metric in the Hilbert space, which makes the non-Hermitian model unitary and ensures the completeness of states, has been constructed explicitly. Although the longitudinal correlation functions are identical for both the non-Hermitian and the Hermitian Ising models, the difference shows up in the transverse correlation functions, which have been calculated explicitly and are not always real. A proper set of Hermitian spin operators in the Hilbert space of the non-Hermitian Hamiltonian has been identified, in terms of which all the correlation functions of the non-Hermitian Hamiltonian become real and identical to that of the standard transverse Ising model. Comments on the quantum phase transitions in the non-Hermitian model have been made.
82C20 Dynamic lattice systems (kinetic Ising, etc.) and systems on graphs
82C23 Exactly solvable dynamic models (See also 37K60)
82C26 Dynamic and nonequilibrium phase transitions (general)
Issue 47 (27 November 2009)
Received 3 July 2009, in final form 18 September 2009
Published 6 November 2009
Tetsuo Deguchi and Pijush K Ghosh 2009 J. Phys. A: Math. Theor. 42 475208
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