Quasi-symmetry groups and many-body scar dynamics

• URL: http://arxiv.org/abs/2007.10380v3
• Date: Fri, 26 Feb 2021 07:05:37 GMT
• Title: Quasi-symmetry groups and many-body scar dynamics
• Authors: Jie Ren, Chenguang Liang, Chen Fang
• Abstract summary: In quantum systems, a subspace spanned by degenerate eigenvectors of the Hamiltonian may have higher symmetries than those of the Hamiltonian itself. When the group is a Lie group, an external field coupled to certain generators of the quasi-symmetry group lifts the degeneracy. We provide two related schemes for constructing one-dimensional spin models having on-demand quasi-symmetry groups.
• Score: 13.95461883391858
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: In quantum systems, a subspace spanned by degenerate eigenvectors of the Hamiltonian may have higher symmetries than those of the Hamiltonian itself. When this enhanced-symmetry group can be generated from local operators, we call it a quasi-symmetry group. When the group is a Lie group, an external field coupled to certain generators of the quasi-symmetry group lifts the degeneracy, and results in exactly periodic dynamics within the degenerate subspace, namely the many-body-scar dynamics (given that Hamiltonian is non-integrable). We provide two related schemes for constructing one-dimensional spin models having on-demand quasi-symmetry groups, with exact periodic evolution of a pre-chosen product or matrix-product state under certain external fields.

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