Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/329104
Type: Artigo
Title: Competing Adiabatic Thouless Pumps In Enlarged Parameter Spaces
Competing adiabatic Thouless pumps in enlarged parameter spaces
Author: Lopes, Pedro L. e S.
Ghaemi, Pouyan
Ryu, Shinsei
Hughes, Taylor L.
Abstract: The transfer of conserved charges through insulating matter via smooth deformations of the Hamiltonian is known as quantum adiabatic, or Thouless, pumping. Central to this phenomenon are Hamiltonians whose insulating gap is controlled by a multidimensional ( usually two-dimensional) parameter space in which paths can be defined for adiabatic changes in the Hamiltonian, i.e., without closing the gap. Here, we extend the concept of Thouless pumps of band insulators by considering a larger, three-dimensional parameter space. We show that the connectivity of this parameter space is crucial for defining quantum pumps, demonstrating that, as opposed to the conventional two-dimensional case, pumped quantities depend not only on the initial and final points of Hamiltonian evolution but also on the class of the chosen path and preserved symmetries. As such, we distinguish the scenarios of closed/open paths of Hamiltonian evolution, finding that different closed cycles can lead to the pumping of different quantum numbers, and that different open paths may point to distinct scenarios for surface physics. As explicit examples, we consider models similar to simple models used to describe topological insulators, but with doubled degrees of freedom compared to a minimal topological insulator model. The extra fermionic flavors from doubling allow for extra gapping terms/adiabatic parameters-besides the usual topological mass which preserves the topology-protecting discrete symmetries-generating an enlarged adiabatic parameter space. We consider cases in one and three spatial dimensions, and our results in three dimensions may be realized in the context of crystalline topological insulators, as we briefly discuss.
The transfer of conserved charges through insulating matter via smooth deformations of the Hamiltonian is known as quantum adiabatic, or Thouless, pumping. Central to this phenomenon are Hamiltonians whose insulating gap is controlled by a multidimensional ( usually two-dimensional) parameter space in which paths can be defined for adiabatic changes in the Hamiltonian, i.e., without closing the gap. Here, we extend the concept of Thouless pumps of band insulators by considering a larger, three-dimensional parameter space. We show that the connectivity of this parameter space is crucial for defining quantum pumps, demonstrating that, as opposed to the conventional two-dimensional case, pumped quantities depend not only on the initial and final points of Hamiltonian evolution but also on the class of the chosen path and preserved symmetries. As such, we distinguish the scenarios of closed/open paths of Hamiltonian evolution, finding that different closed cycles can lead to the pumping of different quantum numbers, and that different open paths may point to distinct scenarios for surface physics. As explicit examples, we consider models similar to simple models used to describe topological insulators, but with doubled degrees of freedom compared to a minimal topological insulator model. The extra fermionic flavors from doubling allow for extra gapping terms/adiabatic parameters-besides the usual topological mass which preserves the topology-protecting discrete symmetries-generating an enlarged adiabatic parameter space. We consider cases in one and three spatial dimensions, and our results in three dimensions may be realized in the context of crystalline topological insulators, as we briefly discuss.
Subject: Electronic-properties
Polarization
Solitons
Polyacetylene
Insulators
Isolantes topológicos, Férmions, Campos magnéticos
Country: Estados Unidos
Editor: American Physical Society
Citation: Physical Review B. Amer Physical Soc, v. 94, p. , 2016.
Rights: aberto
Identifier DOI: 10.1103/PhysRevB.94.235160
Address: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.94.235160
Date Issue: 2016
Appears in Collections:IFGW - Artigos e Outros Documentos

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