Cross-Correlation Investigation of Anyon Statistics in the ν = 1 / 3 and 2 / 5 Fractional Quantum Hall States
Résumé
Recent pioneering works have set the stage for exploring anyon braiding statistics from negative current cross-correlations along two intersecting quasiparticle beams. In such a dual-source-analyzer quantum point contact setup, also referred to as "collider," the anyon exchange phase of fractional quantum Hall quasiparticles is predicted to be imprinted into the cross-correlations characterized by an effective Fano factor P. In the case of symmetric incoming quasiparticle beams, conventional fermions result in a vanishing P. In marked contrast, we observe signatures of anyon statistics in the negative P found both for the e/3 Laughlin quasiparticles at filling factor nu = 1/3 (P -2, corroborating previous findings) and for the e/5 quasiparticles in the hierarchical state nu = 2/5 (P -1). Nevertheless, we argue that the quantitative connection between a numerical value of P not equal 0 and a specific fractional exchange phase is hampered by the influence of the analyzer conductance dependence on the voltages used to generate the quasiparticles. Finally, we address the important challenge how to distinguish at nu = 1/3 between negative cross-correlations induced by a fractional braid phase and those resulting from a different Andreev-like mechanism. Although with symmetric sources P does not exhibit signatures of a crossover when the analyzer is progressively detuned to favor Andreev processes, we demonstrate that changing the balance between sources provides a means to discriminate between the two mechanisms.