Signature of anyonic statistics in the integer quantum Hall regime.

Anyons are exotic low-dimensional quasiparticles whose unconventional quantum statistics extend the binary particle division into fermions and bosons. The fractional quantum Hall regime provides a natural host, with the first convincing anyon signatures recently observed through interferometry and cross-correlations of colliding beams. However, the fractional regime is rife with experimental complications, such as an anomalous tunneling density of states, which impede the manipulation of anyons.

Observation of the scaling dimension of fractional quantum Hall anyons.

Unconventional quasiparticles emerging in the fractional quantum Hall regime present the challenge of observing their exotic properties unambiguously. Although the fractional charge of quasiparticles has been demonstrated for nearly three decades, the first convincing evidence of their anyonic quantum statistics has only recently been obtained and, so far, the so-called scaling dimension that determines the propagation dynamics of the quasiparticles remains elusive. In particular, although the nonlinearity of the tunnelling quasiparticle current should reveal their scaling dimension, the measurements fail to match theory, arguably because this observable is not robust to non-universal complications.

Observing the universal screening of a Kondo impurity.

The Kondo effect, deriving from a local magnetic impurity mediating electron-electron interactions, constitutes a flourishing basis for understanding a large variety of intricate many-body problems. Its experimental implementation in tunable circuits has made possible important advances through well-controlled investigations. However, these have mostly concerned transport properties, whereas thermodynamic observations - notably the fundamental measurement of the spin of the Kondo impurity - remain elusive in test-bed circuits.

Quasiparticle Andreev scattering in the ν = 1/3 fractional quantum Hall regime.

The scattering of exotic quasiparticles may follow different rules than electrons. In the fractional quantum Hall regime, a quantum point contact (QPC) provides a source of quasiparticles with field effect selectable charges and statistics, which can be scattered on an 'analyzer' QPC to investigate these rules. Remarkably, for incident quasiparticles dissimilar to those naturally transmitted across the analyzer, electrical conduction conserves neither the nature nor the number of the quasiparticles.

Electronic heat flow and thermal shot noise in quantum circuits.

When assembling individual quantum components into a mesoscopic circuit, the interplay between Coulomb interaction and charge granularity breaks down the classical laws of electrical impedance composition. Here we explore experimentally the thermal consequences, and observe an additional quantum mechanism of electronic heat transport. The investigated, broadly tunable test-bed circuit is composed of a micron-scale metallic node connected to one electronic channel and a resistance.

Transmitting the quantum state of electrons across a metallic island with Coulomb interaction.

The Coulomb interaction generally limits the quantum propagation of electrons. However, it can also provide a mechanism to transfer their quantum state over larger distances. Here, we demonstrate such a form of electron teleportation across a metallic island.

Solving thermal issues in tensile-strained Ge microdisks.

We propose to use Ge-dielectric-metal stacking to allow one to address both thermal management with the metal as an efficient heat sink and tensile strain engineering with the buried dielectric as a stressor layer. This scheme is particularly useful for the development of Ge-based optical sources. We demonstrate experimentally the relevance of this approach by comparing the optical response of tensile-strained Ge microdisks with an Al heat sink or an oxide pedestal.

Strong coupling and vortexes assisted slow light in plasmonic chain-SOI waveguide systems.

A strong coupling regime is demonstrated at near infrared between metallic nanoparticle chains (MNP), supporting localized surface plasmons (LSP), and dielectric waveguides (DWGs) having different core materials. MNP chains are deposited on the top of these waveguides in such a way that the two guiding structures are in direct contact with each other. The strong coupling regime implies (i) a strong interpenetration of the bare modes forming two distinct supermodes and (ii) a large power overlap up to the impossibility to distinguish the power quota inside each bare structure.

Electrically driven optical metamaterials.

The advent of metamaterials more than 15 years ago has offered extraordinary new ways of manipulating electromagnetic waves. Yet, progress in this field has been unequal across the electromagnetic spectrum, especially when it comes to finding applications for such artificial media. Optical metamaterials, in particular, are less compatible with active functionalities than their counterparts developed at lower frequencies.

Soft UV nanoimprint lithography-designed highly sensitive substrates for SERS detection.

We report on the use of soft UV nanoimprint lithography (UV-NIL) for the development of reproducible, millimeter-sized, and sensitive substrates for SERS detection. The used geometry for plasmonic nanostructures is the cylinder. Gold nanocylinders (GNCs) showed to be very sensitive and specific sensing surfaces.

Integration of short gold nanoparticles chain on SOI waveguide toward compact integrated bio-sensors.

We demonstrate the integration of short metal nanoparticle chains (L ≈700 nm) supporting localized surface plasmons in Silicon On Insulator (SOI) waveguides at telecom wavelengths. Nanoparticles are deposited on the waveguide top and excited through the evanescent field of the TE waveguide modes. Finite difference time domain calculations and waveguide transmission measurements reveal that almost all the TE mode energy can be transferred to nanoparticle chains at resonance.

Giant coupling effect between metal nanoparticle chain and optical waveguide.

We demonstrate that the optical energy carried by a TE dielectric waveguide mode can be totally transferred into a transverse plasmon mode of a coupled metal nanoparticle chain. Experiments are performed at 1.5 μm.

NMR-like control of a quantum bit superconducting circuit.

Coherent superpositions of quantum states have already been demonstrated in different superconducting circuits based on Josephson junctions. These circuits are now considered for implementing quantum bits. We report on experiments in which the state of a qubit circuit, the quantronium, is efficiently manipulated using methods inspired from nuclear magnetic resonance (NMR): multipulse sequences are used to perform arbitrary operations, to improve their accuracy, and to fight decoherence.

Manipulating the quantum state of an electrical circuit.

We have designed and operated a superconducting tunnel junction circuit that behaves as a two-level atom: the "quantronium." An arbitrary evolution of its quantum state can be programmed with a series of microwave pulses, and a projective measurement of the state can be performed by a pulsed readout subcircuit. The measured quality factor of quantum coherence Qphi approximately 25,000 is sufficiently high that a solid-state quantum processor based on this type of circuit can be envisioned.

Radio-frequency single-electron transistor as readout device for qubits: charge sensitivity and backaction.

We study the radio-frequency single-electron transistor (rf-SET) as a readout device for charge qubits. We measure the charge sensitivity of an rf-SET to be 6.3microe/sqrt[Hz] and evaluate the backaction of the rf-SET on a single Cooper-pair box.