Hyperbolic nodal band structures and knot invariants

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Marcus Stålhammar - , Stockholm University (Author)
  • Lukas Rødland - , University of Oslo (Author)
  • Gregory Arone - , Stockholm University (Author)
  • Jan Carl Budich - , Chair of Quantum Many-Body Theory (Author)
  • Emil J. Bergholtz - , Stockholm University (Author)

Abstract

We extend the list of known band structure topologies to include a large family of hyperbolic nodal links and knots, occurring both in conventional Hermitian systems where their stability relies on discrete symmetries, and in the dissipative non-Hermitian realm where the knotted nodal lines are generic and thus stable towards any small perturbation. We show that these nodal structures, taking the forms of Turk’s head knots, appear in both continuum- and lattice models with relatively short-ranged hopping that is within experimental reach. To determine the topology of the nodal structures, we devise an efficient algorithm for computing the Alexander polynomial, linking numbers and higher order Milnor invariants based on an approximate and well controlled parameterisation of the knot.

Details

Original languageEnglish
Article number019
JournalSciPost physics
Volume7
Issue number2
Publication statusPublished - 8 Aug 2019
Peer-reviewedYes

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