Coherence recovery mechanisms in quantum Hall edge states

Abstract

The work is motivated by the puzzling results of the recent experiment [S. Tewari et al., Phys. Rev. B 93, 035420 (2016)], where a robust coherence recovery from a certain energy was detected for an electron injected into the quantum Hall edge at the filling factor 2. After passing through a quantum dot the electron then tunnels into the edge with a subsequent propagation towards a symmetric Mach-Zender interferometer, after which the visibility of Aharonov-Bohm (AB) oscillations is measured. According to conventional understanding its decay with the increasing energy of the injected electron was expected, which was confirmed theoretically in the bosonization framework. Here we analyze why such a model fails to account for the coherence recovery and show that the reason is essentially the destructive interference of the two quasiparticles (charge and neutral modes) forming at the edge out of the incoming electron. This statement is robust with respect to the strength of Coulomb interaction. We firstly exploit the idea of introducing an imbalance between the quasiparticles, by creating different conditions of propagation for them. It can be done by taking into account either dispersion or dissipation, which indeed results in the partial coherence recovery. The idea of imbalance can also be realized by applying a periodic potential to the arms of interferometer. We discuss such an experiment, which might also shed light on the internal coherence of the two edge excitations. Another scenario relies on the lowering of the energy density of the electron wave packet by the time it arrives at the interferometer in presence of dissipation or dispersion. This energy density is defined by a certain parameter, which is completely independent of the injected energy, which naturally explains the emergence of a threshold energy in the experiment.

15 pages, 4 figures

References in corpus (6)

• Direct measurement of the coherence length of edge states in the Integer Quantum Hall Regime
• Dephasing in the electronic Mach-Zehnder interferometer at filling factor 2
• Finite bias visibility of the electronic Mach-Zehnder interferometer
• Decoherence and single electron charging in an electronic Mach-Zehnder interferometer
• Decoherence and relaxation of a single electron in a one dimensional conductor
• Decoherence of high-energy electrons in weakly disordered quantum Hall edge states

Cited by in corpus (6)

• Relaxation and revival of quasiparticles injected in an interacting quantum Hall liquid
• Dephasing in Mach-Zehnder interferometer by an Ohmic contact
• Influence of channel mixing in fermionic Hong-Ou-Mandel experiments
• Electronic wave-packets in integer quantum Hall edge channels: relaxation and dissipative effects
• Quantum transport phenomena induced by time-dependent fields
• The threshold effects in one-dimensional strongly-interacting systems out of equilibrium