Matériaux et Phénomènes Quantiques

MPQ

Tutelles >

Université Paris Diderot

UFR de rattachement >

UFR Physique

Label unité >

UMR

Partenaires >

CNRS

Présentation

Le laboratoire Matériaux et Phénomènes Quantiques (MPQ) est une unité mixte de recherche (UMR 7162) du CNRS et de l’Université Paris Diderot, installée sur le campus de Paris Rive Gauche. Elle est composée d’environ 120 personnes au total dont 51 permanent.e.s.

Le laboratoire est spécialisé dans l’étude des matériaux quantiques de frontière et dans le développement de dispositifs quantiques innovants. Ces activités reposent sur un large spectre de compétences théoriques et expérimentales alliant la physique des matériaux, le transport et l’optique, et des plateformes technologiques de salle blanche, de spectroscopie et de microscopie électronique haute résolution.

Les activités de recherche du laboratoire MPQ se déclinent selon les thèmes suivants :

nouveaux matériaux à l’échelle nano : nanoparticules, nanocristaux, nanotubes fonctionnalisés, matériaux multiferroïques, etc.
nouveaux états de la matière : fluides quantiques de lumière, couplage ultra-fort en cavité, supraconducteurs non-conventionnels, systèmes fortement corrélés, phases topologiques, etc.
systèmes nano-optiques innovants : optomécanique, nanophotonique non-linéaire, nanoplasmonique, etc.
ingénierie quantique et information quantique : composants optoélectroniques quantiques, circuits photoniques quantiques, ions piégés, matériaux et composants hybrides organique/inorganique, ingénierie des surfaces/interfaces.

Les projets actuels du laboratoire incluent le développement de nouvelles sondes pour l’étude des matériaux quantiques, comme la spectroscopie Raman résolue en temps, la microscopie AFM opto-mécanique et la microscopie tunnel sous excitation optique. Réciproquement, les matériaux de frontière sont mis à profit pour la réalisation de nouvelles fonctionnalités dans des senseurs optomécaniques, des circuits photoniques non-linéaires et quantiques, ou encore dans des expériences de transport mésoscopique en cavité optique.

[hal-02064215] Near- and mid-infrared intersubband absorption in top-down GaN/AlN nano- and micro-pillars

Date: 20 jan 2021 - 15:34

Desc: [...]

[hal-02065792] Entanglement of superconducting qubits via acceleration radiation

Date: 20 jan 2021 - 06:51

Desc: We show that simulated relativistic motion can generate entanglement between artificial atoms and protect them from spontaneous emission. We consider a pair of superconducting qubits coupled to a resonator mode, where the modulation of the coupling strength can mimic the harmonic motion of the qubits at relativistic speeds, generating acceleration radiation. We find the optimal feasible conditions for generating a stationary entangled state between the qubits when they are initially prepared in their ground state. Furthermore, we analyse the effects of motion on the probability of spontaneous emission in the standard scenarios of single-atom and two-atom superradiance, where one or two excitations are initially present. Finally, we show that relativistic motion induces sub-radiance and can generate a Zeno-like effect, preserving the excitations from radiative decay.

[hal-02144140] Ballistic transport and boundary resistances in inhomogeneous quantum spin chains

Date: 20 jan 2021 - 04:14

Desc: Transport phenomena are central to physics, and transport in the many-body and fully-quantum regime is attracting an increasing amount of attention. It has been recently revealed that some quantum spin chains support ballistic transport of excitations at all energies. However, when joining two semi-infinite ballistic parts, such as the XX and XXZ spin-1/2 models, our understanding suddenly becomes less established. Employing a matrix-product-state ansatz of the wavefunction, we study the relaxation dynamics in this latter case. Here we show that it takes place inside a light cone, within which two qualitatively different regions coexist: an inner one with a strong tendency towards thermalization, and an outer one supporting ballistic transport. We comment on the possibility that even at infinite time the system supports stationary currents and displays a non-zero Kapitza boundary resistance. Our study paves the way to the analysis of the interplay between transport, integrability, and local defects.

[hal-02273489] Mixing properties of room temperature patch-antenna receivers in a mid-infrared ($\lambda$ $\sim$ 9$\mu$m) heterodyne system

Date: 20 jan 2021 - 00:23

Desc: A room-temperature mid-infrared (9 um) heterodyne system based on high-performance unipolar optoelectronic devices is presented. The local oscillator (LO) is a quantum cascade laser, while the receiver is an antenna coupled quantum well infrared photodetector optimized to operate in a microcavity configuration. Measurements of the saturation intensity show that these receivers have a linear response up to very high optical power, an essential feature for heterodyne detection. By an accurate passive stabilization of the local oscillator and minimizing the optical feed-back the system reaches, at room temperature, a record value of noise equivalent power of 30 pW at 9um. Finally, it is demonstrated that the injection of microwave signal into our receivers shifts the heterodyne beating over the bandwidth of the devices. This mixing property is a unique valuable function of these devices for signal treatment.

[hal-02459857] Full exact solution of the out-of-equilibrium boundary sine Gordon model

Date: 20 jan 2021 - 00:13

Desc: The massless boundary sine-Gordon (SG) model is the only interacting impurity model with a known exact solution out-of-equilibrium, yet existing so far only for integer values of the sine Gordon coupling $\lambda$ [Phys. Rev. Lett. {\bf74}, 3005 (1995)]. We present here a full exact solution for arbitrary rational values of $\lambda$, at arbitrary voltage $V$ and temperature $T$. We use the "string" solutions of the bulk SG model, here regarded as genuine quasiparticles avoiding charge diffusion in momentum space. We carefully present the finite voltage and temperature thermodynamics of this gas of interacting exotic quasiparticles, whose very nature depends on subtle arithmetic properties of the rational SG parameter $\lambda$, and explicitly check that the string representation is thermodynamically complete. By considering a Loschmidt echo, we derive the exact transmission probability of strings on the impurity. We obtain the exact universal scaling function for the electrical current $I(V,T)$. Our results are in excellent agreement with recent experimental out-of-equilibrium data and question the reality of these exotic quasiparticles.