arXiv subjects

M. Acciai

Publications and source records attributed to M. Acciai.

3 recordsLinked to original sources

arXiv2022

Two-particle time-domain interferometry in the Fractional Quantum Hall Effect regime

Quasi-particles are elementary excitations of condensed matter quantum phases. Demonstrating that they keep quantum coherence while propagating is a fundamental issue for their manipulation for quantum information tasks. Here, we consider anyons, the fractionally charged quasi-particles 20 of the Fractional Quantum Hall Effect occurring in two-dimensional electronic conductors in high magnetic fields. They obey anyonic statistics, intermediate between fermionic and bosonic. Surprisingly, anyons show large quantum coherence when transmitted through the localized states of electronic Fabry-Pérot interferometers, but almost no quantum interference when transmitted via the propagating states of Mach-Zehnder interferometers. Here, using a novel interferometric 25 approach, we demonstrate that anyons do keep quantum coherence while propagating. Performing two-particle time-domain interference measurements sensitive to the two-particle Hanbury Brown Twiss phase, we find 53% and 60% visibilities for anyons with charges e/5 and e/3. Our results give a positive message for the challenge of performing controlled quantum coherent braiding of anyons.

cond-mat.mes-hall↗

arXiv2020

Collisional interferometry of Levitons in quantum Hall edge channels at $ν=2$

We consider a Hong-Ou-Mandel interferometer for Lorentzian voltage pulses applied to Quantum Hall edge channels at filling factor $ν=2$. Due to inter-edge interactions, the injected electronic wave-packets fractionalize before partitioning at a quantum point contact. Remarkably enough, differently from what theoretically predicted and experimentally observed by using other injection techniques, we demonstrate that, when the injection occurs through time-dependent voltage pulses (arbitrarily shaped), the Hong-Ou-Mandel noise signal always vanishes for a symmetric device, and that a mismatch in the distances between the injectors and the point of collision is needed in order to reduce the visibility of the dip. We also show that, by properly tuning these distances or by applying different voltages on the two edge channels in each arm of the interferometer, it is possible to estimate the intensity of the inter-edge interaction. The voltage pulses are chosen of the Lorentzian type because of their experimental relevance.

cond-mat.mes-hall↗

arXiv2018

Hong-Ou-Mandel characterization of multiply charged Levitons

We review and develop recent results regarding Leviton excitations generated in topological states of matter - such as integer and fractional quantum Hall edge channels - and carrying a charge multiple of the electronic one. The peculiar features associated to these clean and robust emerging excitations can be detected through current correlation measurements. In particular, relevant information can be extracted from the noise signal in generalized Hong-Ou-Mandel experiments, where Levitons with different charges collide against each other at a quantum point contact. We describe this quantity both in the framework of the photo-assisted noise formalism and in terms of a very interesting and transparent picture based on wave-packet overlap.

cond-mat.mes-hall↗