Interferometry of non-Abelian band singularities and Euler class topology

Fuente: arXiv
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Autores principales: Breach, Oliver, Slager, Robert-Jan, Ünal, F. Nur
Formato: Preprint
Publicado: 2024
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author Breach, Oliver
Slager, Robert-Jan
Ünal, F. Nur
author_facet Breach, Oliver
Slager, Robert-Jan
Ünal, F. Nur
contents In systems with a real Bloch Hamiltonian band nodes can be characterised by a non-Abelian frame-rotation charge. The ability of these band nodes to annihilate pairwise is path dependent, since by braiding nodes in adjacent gaps the sign of their charges can be changed. Here, we theoretically construct and numerically confirm two concrete methods to experimentally probe these non-Abelian braiding processes and charges in ultracold atomic systems. We consider a coherent superposition of two bands that can be created by moving atoms through the band singularities at some angle in momentum space. Analyzing the dependency of excitations on the frame charges, we demonstrate an interferometry scheme passing through two band nodes, which reveals the relative frame charges and allows for measuring the multi-gap topological invariant. The second method relies on a single wavepacket probing two nodes sequentially, where the frame charges can be determined from the band populations. Our results present a feasible avenue for measuring non-Abelian charges of band nodes and the direct experimental verification of braiding procedures, which can be applied in a variety of settings including the recently discovered anomalous non-Abelian phases arising under periodic driving.
format Preprint
id arxiv_https___arxiv_org_abs_2401_01928
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Interferometry of non-Abelian band singularities and Euler class topology
Breach, Oliver
Slager, Robert-Jan
Ünal, F. Nur
Quantum Gases
Mesoscale and Nanoscale Physics
Atomic Physics
Quantum Physics
In systems with a real Bloch Hamiltonian band nodes can be characterised by a non-Abelian frame-rotation charge. The ability of these band nodes to annihilate pairwise is path dependent, since by braiding nodes in adjacent gaps the sign of their charges can be changed. Here, we theoretically construct and numerically confirm two concrete methods to experimentally probe these non-Abelian braiding processes and charges in ultracold atomic systems. We consider a coherent superposition of two bands that can be created by moving atoms through the band singularities at some angle in momentum space. Analyzing the dependency of excitations on the frame charges, we demonstrate an interferometry scheme passing through two band nodes, which reveals the relative frame charges and allows for measuring the multi-gap topological invariant. The second method relies on a single wavepacket probing two nodes sequentially, where the frame charges can be determined from the band populations. Our results present a feasible avenue for measuring non-Abelian charges of band nodes and the direct experimental verification of braiding procedures, which can be applied in a variety of settings including the recently discovered anomalous non-Abelian phases arising under periodic driving.
title Interferometry of non-Abelian band singularities and Euler class topology
topic Quantum Gases
Mesoscale and Nanoscale Physics
Atomic Physics
Quantum Physics
url https://arxiv.org/abs/2401.01928