Quantum dot dephasing by fractional quantum Hall edge states

Thi Kim Thanh Nguyen (1, 2, 3) , Adeline Crépieux (1, 3) , Thibaut Jonckheere (1, 3) , Ai Viet Nguyen (2) , Yeoshua Levinson (4) , Thierry Martin (1, 3)

1 CPT - Centre de Physique Théorique - UMR 6207
2 Institute of Physics and Electronics
3 CPT - Centre de Physique Théorique - UMR 7332
4 Weizmann Institute of Science [Rehovot, Israël]

We consider the dephasing rate of an electron level in a quantum dot, placed next to a fluctuating edge current in the fractional quantum Hall effect. Using perturbation theory, we show that this rate has an anomalous dependence on the bias voltage applied to the neighboring quantum point contact, which originates from the Luttinger liquid physics which describes the Hall fluid. General expressions are obtained using a screened Coulomb interaction. The dephasing rate is strictly proportional to the zero frequency backscattering current noise, which allows to describe exactly the weak to strong backscattering crossover using the Bethe-Ansatz solution.

Mots clés: dephasing; noise; fractional Hall effect; quasiparticle

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Thi Kim Thanh Nguyen, Adeline Crépieux, Thibaut Jonckheere, Ai Viet Nguyen, Yeoshua Levinson, et al.. Quantum dot dephasing by fractional quantum Hall edge states. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2006, 74, pp.153303. ⟨hal-00079042v2⟩