Jérôme Rech

Electron quantum optics in ballistic chiral conductors

The edge channels of the quantum Hall effect provide one dimensional chiral and ballistic wires along which electrons can be guided in an optics-like setup. Electronic propagation can then be analyzed using concepts and tools derived from optics. After a brief review of electron optics experiments performed using stationary current sources which continuously emit electrons in the conductor, this paper focuses on triggered sources, which can generate on-demand a single particle state. It first outlines the electron optics formalism and its analogies and differences with photon optics and then turns to the presentation of single electron emitters and their characterization through the measurements of the average electrical current and its correlations. This is followed by a discussion of electron quantum optics experiments in the Hanbury-Brown and Twiss geometry where two-particle interferences occur. Finally, Coulomb interactions effects and their influence on single electron states are considered.

Instability of the Quantum-Critical Point of Itinerant Ferromagnets

We study the stability of the Quantum Critical Point (QCP) for itinerant ferromagnets commonly described by the Hertz-Millis-Moriya (HMM) theory. We argue that in

Stochastic Self-Assembly of ParB Proteins Builds the Bacterial DNA Segregation Apparatus

D \leq 3

Electron and hole Hong-Ou-Mandel interferometry

, long-range spatial correlations associated with the Landau damping of the order parameter field generate a universal {\it negative}, non-analytic

Interactions and charge fractionalization in an electronic Hong-Ou-Mandel interferometer

|q|^{(D+1)/2}

Decoherence and relaxation of a single electron in a one-dimensional conductor

contribution to the static magnetic susceptibility

Bacterial partition complexes segregate within the volume of the nucleoid

\chi_s (q, 0)

Minimal Excitations in the Fractional Quantum Hall Regime

, which makes HMM theory unstable. We argue that the actual transition is either towards incommensurate ordering, or first order. We also show that singular corrections are specific to the spin problem, while charge susceptibility remains analytic at criticality.

Electronic Hong-Ou-Mandel interferometry in two-dimensional topological insulators

Many canonical processes in molecular biology rely on the dynamic assembly of higher-order nucleoprotein complexes. In bacteria, the assembly mechanism of ParABS, the nucleoprotein super-complex that actively segregates the bacterial chromosome and many plasmids, remains elusive. We combined super-resolution microscopy, quantitative genome-wide surveys, biochemistry, and mathematical modeling to investigate the assembly of ParB at the centromere-like sequences parS. We found that nearly all ParB molecules are actively confined around parS by a network of synergistic protein-protein and protein-DNA interactions. Interrogation of the empirically determined, high-resolution ParB genomic distribution with modeling suggests that instead of binding only to specific sequences and subsequently spreading, ParB binds stochastically around parS over long distances. We propose a new model for the formation of the ParABS partition complex based on nucleation and caging: ParB forms a dynamic lattice with the DNA around parS. This assembly model and approach to characterizing large-scale, dynamic interactions between macromolecules may be generalizable to many unrelated machineries that self-assemble in superstructures.

Single quasiparticle and electron emitter in the fractional quantum Hall regime

We consider the electronic analog of the quantum optics Hong-Ou-Mandel interferometer, in a realistic condensed matter device based on single electron emission in chiral edge states. For electron-electron collisions, we show that the measurement of the zero-frequency current correlations at the output of a quantum point contact produces a dip giving precious information on the electronic wavepackets and coherence. As a feature truly unique to Fermi statistics and condensed matter, we show that two-particle interferences between electron and hole in the Fermi sea can produce a positive peak in the current correlations, which we study for realistic experimental parameters.