Sacco Shaikh, D.; Sassetti, M.; Traverso Ziani, N. Parity-Dependent Quantum Phase Transition in the Quantum Ising Chain in a Transverse Field. Symmetry2022, 14, 996.
Sacco Shaikh, D.; Sassetti, M.; Traverso Ziani, N. Parity-Dependent Quantum Phase Transition in the Quantum Ising Chain in a Transverse Field. Symmetry 2022, 14, 996.
Sacco Shaikh, D.; Sassetti, M.; Traverso Ziani, N. Parity-Dependent Quantum Phase Transition in the Quantum Ising Chain in a Transverse Field. Symmetry2022, 14, 996.
Sacco Shaikh, D.; Sassetti, M.; Traverso Ziani, N. Parity-Dependent Quantum Phase Transition in the Quantum Ising Chain in a Transverse Field. Symmetry 2022, 14, 996.
Abstract
Phase transitions- both in the classical and in the quantum version- are the perfect playground for appreciating universality at work. Indeed, the fine details become unimportant and a classification in very few universality classes is possible. Very recently, a striking deviation from this picture has been discovered: some antiferromagnetic spin chains with competing interactions show a different set of phase transitions depending on the parity of number of spins in the chain. The aim of this article is to demonstrate that the same behavior also characterizes the most simple quantum spin chain: the Ising model in a transverse field. By means of an exact solution based on a Wigner-Jordan transformation, we show that a first order quantum phase transition appears at zero applied field in the odd spin case, while it is not present in the even case. A hint of a possible physical interpretation is given by the combination of two fact: at the point of the phase transition, the degeneracy of the ground state in the even and the odd case substantially differ, being respectively 2 and 2N, with N the number of spins; the spin of the most favorable kink states changes at that point.
Copyright:
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