B. Etienne

Observation of the e/3 Fractionally Charged Laughlin Quasiparticle

The existence of fractional charges carrying current is experimentally demonstrated. Using a 2D electron system in a high perpendicular magnetic field we measure the shot noise associated with tunneling in the fractional quantum Hall regime at Landau level filling factor 1/3. The noise gives a direct determination of the quasiparticle charge, which is found to be

An On-Demand Coherent Single Electron Source

{e}^{*}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}e/3

Violation of Kirchhoff's Laws for a Coherent RC Circuit

as predicted by Laughlin. The existence of

Persistent Currents in Mesoscopic Connected Rings

e/3

Reduction in the concentration of DX centers in Si‐doped GaAlAs using the planar doping technique

Laughlin quasiparticles is unambiguously confirmed by the shot noise to Johnson-Nyquist noise crossover found for temperature

Optical evidences of assisted tunneling in a biased double quantum well structure

\ensuremath{\Theta}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}e}^{*}{V}_{\mathrm{ds}}/{2k}_{B}

Relaxation Time of a Chiral Quantum R-L Circuit

.

Quantum partition noise of photon-created electron-hole pairs.

We report on the electron analog of the single-photon gun. On-demand single-electron injection in a quantum conductor was obtained using a quantum dot connected to the conductor via a tunnel barrier. Electron emission was triggered by the application of a potential step that compensated for the dot-charging energy. Depending on the barrier transparency, the quantum emission time ranged from 0.1 to 10 nanoseconds. The single-electron source should prove useful for the use of quantum bits in ballistic conductors. Additionally, periodic sequences of single-electron emission and absorption generate a quantized alternating current.

Experiments on ordering in classical and quantum 2D electron systems

What is the complex impedance of a fully coherent quantum resistance-capacitance (RC) circuit at gigahertz frequencies in which a resistor and a capacitor are connected in series? While Kirchhoffs laws predict addition of capacitor and resistor impedances, we report on observation of a different behavior. The resistance, here associated with charge relaxation, differs from the usual transport resistance given by the Landauer formula. In particular, for a single-mode conductor, the charge-relaxation resistance is half the resistance quantum, regardless of the transmission of the mode. The new mesoscopic effect reported here is relevant for the dynamical regime of all quantum devices.

Time-resolved spin-polarization spectroscopy in GaAs/AlGaAs quantum wells

We report measurements of the low temperature magnetic response of a line of 16 GaAs/GaAlAs connected mesoscopic rings whose total length is much larger than l(straight phi). Using an on-chip micro-SQUID technology, we have measured a periodic response, with period h/e, corresponding to persistent currents in the rings of a typical amplitude of 0.40+/-0.08 nA per ring. Direct comparison with measurements on the same rings but isolated is presented.