A singular Landau orbital magnetism of graphene, with a sharp narrow diamagnetic peak at the Dirac point was already predicted in 1956 by McClure. It is now understood as a fundamental signature of the characteristic Berry phase of graphene’s electronic wave functions.
Using a highly sensitive giant magnetoresistance (GMR) sensor, we have measured the gate
voltage–dependent...
Topological adiabatic dynamics is at the origin of the transport properties of topological insulators, topological pumps, or the recently proposed frequency converters.
In this talk I will discuss the fate of such topological properties beyond the adiabatic regime. I will consider a simple setup of two quantum harmonic oscillators strongly coupled to a qubit. On short timescales, this...
Topological Insulators (TIs) hold great promise for making novel electronic devices, thanks to the existence at their boundaries of topologically protected conduction channels. Unfortunately, the expected protection has turned out to be less robust than anticipated, notably due to inelastic processes involving bulk excitations. This complicates the fundamental study of the edge states, and...
When electrons populate a flat band their kinetic energy becomes negligible, forcing them to organize in exotic many-body states to minimize their Coulomb energy. The zeroth Landau level of graphene under magnetic field is a particularly interesting strongly interacting flat band because inter-electron interactions are predicted to induce a rich variety of broken-symmetry states with distinct...
In the field of topological photonics, exciton-polariton cavities have emerged as a promising platform, thanks to the complementary nature of their matter and light components. Indeed, the excitonic part provides large non-linearities and susceptibility to magnetic fields, allowing time-reversal symmetry breaking, whereas the photonic part allows the engineering of gain, losses or the...
Vacuum breakdown by particle-antiparticle pair creation under intense electric field, introduced by Sauter and Schwinger, is a basic non-perturbative prediction of quantum electrodynamics. Its high-energy physics experimental demonstration remains elusive as the threshold electric fields are extremely strong and beyond current reach, even for the light electron-positron pairs.
Here we put...
The transport properties of quantum conductors can strongly change when embedded in an on-chip dissipative mesoscopic circuit. At the heart of this phenomenon is the Coulomb energy required to change the charge in small interconnect nodes of the circuit. Handling the dynamics of charge is a huge theoretical challenge beyond perturbative regimes. Yet, the suppression of the electrical...
Les jonctions hybrides supraconducteur-semiconducteur sont un élément clé afin d’obtenir des supraconducteurs topologiques ou des bits quantiques supraconducteurs pilotables avec une grille électrostatique. La qualité et la reproductibilité de l’interface supraconducteur-semiconducteur est cruciale pour garantir le succès de ces applications.
Récemment, une nouvelle méthode pour obtenir des...
In nature the emission of photon from electronic relaxation is a well known phenomenon. The rate at which this process happens is controlled by the fine structure constant α=1/137. Because of this small value, the emission of more than one photon from a single relaxation event is a very rare event in nature and in optical experiments. In order to increase the probability of emission of photon...
Superconductivity and magnetism are antagonistic phenomena whose competing interaction results in novel states and unusual properties that, beyond their fundamental interest, present much potential for rupture technologies. One of the promising examples is the so-called superconducting spintronics, which aims at marrying the spin-polarized transport characteristic of ferromagnets with the...
Single photon detectors based on low temperature superconducting nanowires (SNSPD) have shown unmatched performance in terms of detection efficiency, count rate, jitter... and are currently commercially available.The possibility of achieving single-photon detection with high-temperature superconducting nanowires has been the subject of much theoretical work and intense debate, but there is no...
Les alliages semi-conducteurs sont communément utilisés afin d'ajuster les propriétés électroniques et optiques des régions actives de dispositifs. En particulier, l'ajustement de l'énergie de bande interdite est une composante essentielle de la conception des dispositifs. Cependant, les alliages présentent en général un certain degré de désordre de par la disposition aléatoire sur le réseau...
