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Free fermions in disguise.
- Source :
-
Journal of Physics A: Mathematical & Theoretical . 8/16/2019, Vol. 52 Issue 33, p1-1. 1p. - Publication Year :
- 2019
-
Abstract
- I solve a quantum chain whose Hamiltonian is comprised solely of local four-fermi operators by constructing free-fermion raising and lowering operators. The free-fermion operators are both non-local and highly non-linear in the local fermions. This construction yields the complete spectrum of the Hamiltonian and an associated classical transfer matrix. The spatially uniform system is gapless with dynamical critical exponent zāā=āā3/2, while staggering the couplings gives a more conventional free-fermion model with an Ising transition. The Hamiltonian is equivalent to that of a spin-1/2 chain with next-nearest-neighbour interactions, and has a supersymmetry generated by a sum of fermion trilinears. The supercharges are part of a large non-abelian symmetry algebra that results in exponentially large degeneracies. The model is integrable for either open or periodic boundary conditions but the free-fermion construction only works for the former, while for the latter the extended symmetry is broken and the degeneracies split. [ABSTRACT FROM AUTHOR]
- Subjects :
- *FERMIONS
*CRITICAL exponents
*TRANSFER matrix
*ISING model
*ALGEBRA
*SUPERSYMMETRY
Subjects
Details
- Language :
- English
- ISSN :
- 17518113
- Volume :
- 52
- Issue :
- 33
- Database :
- Academic Search Index
- Journal :
- Journal of Physics A: Mathematical & Theoretical
- Publication Type :
- Academic Journal
- Accession number :
- 137672702
- Full Text :
- https://doi.org/10.1088/1751-8121/ab305d