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Transport and statistics of anyons in the quantum Hall regime

Pierre Glidic (Univ Lund, Sweden)
When Feb 05, 2025
from 02:00 to 03:00
Where Amphi F
Attendees Pierre Glidic
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In the fractional quantum Hall regime, bulk quasiparticles exhibit exotic properties including a fractional charge and, most remarkably, an inter-exchange (braiding) statistics intermediate between that of fermions and bosons. While the fractional charge of these so-called 'anyons' is experimentally firmly confirmed, obtaining clear evidence of their unconventional transport processes and non-trivial braiding statistics has proven to be more challenging tasks.

Recently, considerable focus has been placed on the so-called ‘collider’ approach, involving several quantum point contacts (QPC) in series: one or several upstream sources of quasiparticles and a downstream analyser QPC [1-4]. In this set-up, theory predicts [5-6] that the resulting current cross-correlations between the two outgoing paths (⟨δILδIR⟩, see Fig.1) reveal the quasiparticles exotic properties. In this talk, I will present measurements performed in the integer and fractional quantum Hall regimes revealing such exotic properties.

Firstly, in the emblematic Laughlin’s fraction 1/3, I will present cross-correlations signatures of an unconventional transport process of quasiparticle, coined “Andreev-like scattering”. In the case of a e/3 charged quasiparticle arriving on a barrier transmitting conventional charge e, the impinging quasiparticle is converted into a transmitted charge e and a backscattered quasihole of charge -2e/3 [7].

Secondly, in the case of two sources the observation of a large negative cross-correlations signal for symmetric sources provides evidence of fractional anyon statistics in the emblematic Laughlin fraction 1/3. In the Jain fraction 2/5, similar noise measurements in the inner edge channel also result in negative cross-correlations, which also indicate a different fractional anyon statistics.

Interestingly, at integer filling factor ν=2 involving the emission of electrons, a small negative signal can also be observed when the symmetric sources are set to a high or low transmission. In this case, thanks to the interactions between the two copropagating channels, an initial electron fractionalizes, and the resulting quasiparticle also exhibits anyonic braiding phase signature [7-8].

References
[1] H. Bartolomei et al., Science 368, 173 (2020)
[2] P. Glidic et al., Phys. Rev. X 13, 011030 (2023)
[3] M. Ruelle et al. Phys Rev. X 13, 011031 (2023)
[5] B. Rosenow et al. Phys. Rev., Lett. 116, 156802 (2016)
[6] B. Lee et al., Phys. Rev. Lett. 123, 016803 (2019)
[7] P. Glidic et al., Nat Com. 14, 514 (2023)
[8] E. Idrisov et al., Phys. Rev. B 106, 08540 (2022)
[9] P. Glidic et al, Nat. Com. 15, 6578 (2024)