The chiral anomaly in real space

Abstract

The chiral anomaly is based on a non-conserved chiral charge and can happen in Dirac fermion systems under the influence of external electromagnetic fields. In this case, the spectral flow leads to a transfer of right- to left-moving excitations or vice versa. The corresponding transfer of chiral particles happens in momentum space. We here describe an intriguing way to introduce the chiral anomaly into real space. Our system consists of two quantum dots that are formed at the helical edge of a quantum spin Hall insulator on the basis of three magnetic impurities. Such a setup gives rise to fractional charges which we show to be sharp quantum numbers for large barrier strength. Interestingly, it is possible to map the system onto a quantum spin Hall ring in the presence of a flux pierced through the ring where the relative angle between the magnetization directions of the impurities takes the role of the flux. The chiral anomaly in this system is then directly related to the excess occupation of particles in the two quantum dots. This analogy allows us to predict an observable consequence of the chiral anomaly in real space.

arXiv comment7 pages, 5 figures

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• Helical Liquids in Semiconductors
• ${\mathbb{Z}}_4$ parafermions in weakly interacting superconducting constrictions at the helical edge of quantum spin Hall insulators
• Quantum Transport in Topological Semimetals under Magnetic Fields (II)
• From fractional solitons to Majorana fermions in a paradigmatic model of topological superconductivity
• Formation and detection of Majorana modes in quantum spin Hall trenches
• Fractional charge oscillations in quantum spin Hall quantum dots
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• Signatures of Jackiw-Rebbi resonance in the thermal conductance of topological Josephson junctions with magnetic islands
• Universal scaling of quench-induced correlations in a one-dimensional channel at finite temperature
• The invisible Majorana bound state at the helical edge
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• Fractional boundary charges with quantized slopes in interacting one- and two-dimensional systems
• Jackiw-Rebbi zero modes in non-uniform topological insulator nanowire
• Backscattering off a driven Rashba impurity at the helical edge
• The One-dimensional Chiral Anomaly and its Disorder Response
• Assessing bound states in a one-dimensional topological superconductor: Majorana versus Tamm
• Photocurrent and photoconductance of an helical edge state
• Fractionally charged anyon generated by topological path fusion in magnetic flux lattice
• Effective metal-insulator non-equilibrium quantum phase transition
• Detection of fractional solitons in quantum spin Hall systems