arXiv subjects

Imen Taktak

Publications and source records attributed to Imen Taktak.

3 recordsLinked to original sources

arXiv2025

Hong-Ou-Mandel interferometry for fractional excitations: Unified framework and dip width scaling

Extending Hong--Ou--Mandel (HOM) interferometry to the fractional quantum Hall effect (FQHE) promises direct access to anyonic statistics, yet remains challenging: on-demand anyon injection is hindered by integer-charged minimal excitations, and recent HOM experiments in the FQHE lack a fully consistent theoretical framework. Here we provide a general theory of time-resolved HOM interferometry in quantum Hall systems. Combining the nonequilibrium bosonized edge theory (NEBET) with the unifying non-equilibrium perturbative theory (UNEPT), we derive exact and perturbative relations obeyed by the relevant cross-correlations of chiral currents valid for spatially extended tunneling operators and generic quadratic edge dynamics. Then, within the Tomonaga--Luttinger liquid (TLL) framework, we analyze the width of the HOM dip for injected pulses carrying integer and fractional charges. We show that it is governed by the width of the pulses and, for the fractional charge, by a non-trivial power-law behavior of the scaling dimension. Our results establish a robust theoretical foundation for interpreting recent experiments on anyonic statistics and electronic interferometry in the quantum Hall regime.

cond-mat.mes-hall↗

arXiv2025

AC driven fractional quantum Hall systems: Uncovering unexpected features

We investigate the challenges of reaching the quantum regime and generating minimal excitations in the fractional quantum Hall effect (FQHE) under AC driving. Using the unifying non-equilibrium perturbative (UNEP) approach, we analyze weak backscattering through a quantum point contact (QPC). In both two-terminal geometries and the "anyon collider" setup, the lower bound on photoassisted backscattering noise is set by the photoassisted current rather than the DC noise predicted by Levitov's theorem. This super-Poissonian character is confirmed within the Tomonaga-Luttinger liquid (TLL) framework, where Levitov's theorem is violated, challenging the conventional interpretation of "photoassisted" noise. In the two-terminal geometry, we show that when the QPC has a low scaling dimension, two challenges arise: first, achieving the expected power-law behavior in the DC regime, and second, maintaining the AC quantum regime, where the drive frequency exceeds the temperature, when the DC voltage component is resonant with that drive frequency. The validity of the UNEP relations imposes a lower bound on temperature and a persisting equilibrium contribution to backscattering noise. This forces us to choose a high enough scaling dimension, for which we find that it is rather the photoconductance, often overlooked, that might exhibit spikes at resonant DC voltages, providing a reliable probe of fractional charge. Moreover, we highlight that the zero-temperature limit, frequently assumed in prior studies, including X. G. Wen's foundational work, is inappropriate in this context. Our findings extend beyond the FQHE to coherent conductors and Josephson or phase-slip junctions strongly coupled to an ohmic environment under AC bias, with broader implications for quantum transport and minimal excitation engineering.

cond-mat.mes-hall↗

arXiv2022

Influence of channel mixing in fermionic Hong-Ou-Mandel experiments

We consider an electronic Hong-Ou-Mandel interferometer in the integer quantum Hall regime, where the colliding electronic states are generated by applying voltage pulses (creating for instance Levitons) to ohmic contacts. The aim of this work is to investigate possible mechanisms leading to a reduced visibility of the Pauli dip, i.e., the noise suppression expected for synchronized sources. It is known that electron-electron interactions cannot account for this effect and always lead to a full suppression of the Hong-Ou-Mandel noise. Focusing on the case of filling factor $ν=2$, we show instead that a reduced visibility of the Pauli dip can result from mixing of the copropagating edge channels, arising from tunneling events between them.

cond-mat.mes-hall↗