Edge Physics of the Quantum Spin Hall Insulator from a Quantum Dot Excited by Optical Absorption

Abstract

The gapless edge modes of the Quantum Spin Hall insulator form a helical liquid in which the direction of motion along the edge is determined by the spin orientation of the electrons. In order to probe the Luttinger liquid physics of these edge states and their interaction with a magnetic (Kondo) impurity, we consider a setup where the helical liquid is tunnel-coupled to a semiconductor quantum dot which is excited by optical absorption, thereby inducing an effective quantum quench of the tunneling. At low energy, the absorption spectrum is dominated by a power-law singularity. The corresponding exponent is directly related to the interaction strength (Luttinger parameter) and can be computed exactly using boundary conformal field theory thanks to the unique nature of the Quantum Spin Hall edge.

4.5 pages, 2 figures. v2: published version, new supplemental material section

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Cited by in corpus (7)

• Universal quench dynamics of interacting quantum impurity systems
• Universal nonequilibrium signatures of Majorana zero modes in quench dynamics
• Quantum Quenches in a Holographic Kondo Model
• Multifractal Orthogonality Catastrophe in 1D Random Quantum Critical Points
• Transient Loschmidt Echo in Quenched Ising Chains
• Dynamical transport measurement of the Luttinger parameter in helical edges states of 2D topological insulators
• Dynamics of the impurity screening cloud following quantum quenches of the Resonant Level Model