1. Lieb-Schultz-Mattis theorems and generalizations in long-range interacting systems
- Author
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Liu, Ruizhi, Yi, Jinmin, Zhou, Shiyu, and Zou, Liujun
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Quantum Gases ,Mathematical Physics ,Mathematics - Operator Algebras ,Quantum Physics - Abstract
In a unified fashion, we establish Lieb-Schultz-Mattis (LSM) theorems and their generalizations in systems with long-range interactions. We show that, for a quantum spin chain, if the interactions decay fast enough as their ranges increase and the Hamiltonian has an anomalous symmetry, the Hamiltonian cannot have a unique gapped symmetric ground state. If the Hamiltonian contains only 2-spin interactions, these theorems hold when the interactions decay faster than $1/r^2$, with $r$ the distance between the two interacting spins. Moreover, any pure state with an anomalous symmetry, which may not be a ground state of any natural Hamiltonian, must be long-range entangled. The symmetries we consider include on-site internal symmetries combined with lattice translation symmetries, and they can also extend to purely internal but non-on-site symmetries. Moreover, these internal symmetries can be discrete or continuous. We explore the applications of the theorems through various examples., Comment: 4.5 pages + supplemental material
- Published
- 2024