Quasiadiabatic continuation of quantum states: The stability of topological ground-state degeneracy and emergent gauge invariance
- Center for Nonlinear Studies and Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
We define for quantum many-body systems a quasiadiabatic continuation of quantum states. The continuation is valid when the Hamiltonian has a gap, or else has a sufficiently small low-energy density of states, and thus is away from a quantum phase transition. This continuation takes local operators into local operators, while approximately preserving the ground-state expectation values. We apply this continuation to the problem of gauge theories coupled to matter, and propose the distinction of perimeter law versus 'zero law' to identify confinement. We also apply the continuation to local bosonic models with emergent gauge theories. We show that local gauge invariance is topological and cannot be broken by any local perturbations in the bosonic models in either continuous or discrete gauge groups. We show that the ground-state degeneracy in emergent discrete gauge theories is a robust property of the bosonic model, and we argue that the robustness of local gauge invariance in the continuous case protects the gapless gauge boson.
- OSTI ID:
- 20719161
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 72, Issue 4; Other Information: DOI: 10.1103/PhysRevB.72.045141; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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