Data-Gouv-ML/pcri-erc-participations-et-projets-laureats huggingface dataset:
Projet ERC : EQuO (Horizon 2020, appel 2014, Consolidator grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Condensed matter physics
Entité participante : Sorbonne Université — Pays : France — Rôle : Partner
Acronyme de l'entité : Sorbonne U
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 444027.5 €

Quantum effects have been studied on photon propagation in the context of quantum optics since the second half of the last century. In particular, using single photon emitters, fundamental tests of quantum mechanics were explored by manipulating single to few photons in Hanbury-Brown and Twiss and Hong Ou Mandel experiments. In nanophysics, there is a growing interest to translate these concepts of quantum optics to electrons propagating in nanostructures. Single electron emitters have been realized such that single elementary electronic excitations can now be manipulated in the analog of pioneer quantum optics experiments. Electron quantum optics goes beyond the mere reproduction of optical setups using electron beams, as electrons, being interacting fermions, differ strongly from photons. Contrary to optics, understanding the propagation of an elementary excitation requires replacing the single body description by a many body one. The purpose of this proposal is to specifically explore the emergence of many body physics and its effects on electronic propagation using the setups and concepts of electron quantum optics. The motivations are numerous: firstly single particle emission initializes a simple and well controlled state. I will take this unique opportunity to test birth, life and death scenarii of Landau quasiparticles and observe the emergence of many-body physics. Secondly, I will address the generation of entangled few electrons quantum coherent states and study how they are affected by interactions. Finally, I will attempt to apply electron quantum optics concepts to a regime where the ground state itself is a strongly correlated state of matter. In such a situation, elementary excitations are no longer electrons but carry a fractional charge and obey fractional statistics. No manipulation of single quasiparticles has been reported yet and the determination of some quasiparticle characteristics, such as the fractional statistics remains elusive.

Mots-clés : single electrons,quantum optics with electrons,noise,hong ou mandel,coulomb interaction,decoherence,fractional quantum hall effect
Projet ERC : QUANTIVIOL (Horizon 2020, appel 2016, Consolidator grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Fundamental constituents of matter
Entité participante : University of Amsterdam — Pays : Pays-Bas — Rôle : PI
Acronyme de l'entité : UvA
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 2000000.0 €

Quantum gravity must violate at least one of three principles at the foundations of physics: unitarity, causality, or the equivalence principle. Recent theoretical work on black holes has shown that such violations are not limited to extremely short distances, where quantum gravity effects are expected, but also occur at distances much larger than the Planck scale. This work has revealed a huge gap in our understanding: we have no working criterion for when quantum gravity violations of the usual laws of physics are important. This theoretical crisis is also an opportunity, since quantum gravity effects may be observable if they occur at longer distance scales. I propose a series of concrete calculations in two theoretical situations: ordinary black holes, which evaporate due to Hawking radiation, and black holes in spacetimes with negative cosmological constant, which do not evaporate. These calculations will quantify, for the first time, the size of these violations.The calculations make use of existing techniques and results derived by myself and others, but a focused effort is needed in order to put together all of the necessary ingredients into a coherent quantitative result. We will then generalize our results beyond black holes to obtain a generally applicable formula. The final result will be an answer to one of the most important questions in quantum gravity: how large are quantum gravity violations of the usual laws of physics? The impact of successfully completing this project extends far beyond black hole physics. As one application, our results will either justify existing calculations of cosmological observables, or make a prediction that quantum gravity effects can be observed.

Mots-clés : black holes
Projet ERC : UniRand (Horizon 2020, appel 2020, Starting grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Fundamental constituents of matter
Entité participante : Heidelberg University — Pays : Allemagne — Rôle : Partner
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 0.0 €

Quantum information theory points to new ways of classifying matter. Instead of focusing on microscopic correlation functions, it hinges on global properties of quantum states such as the presence and scaling of entanglement entropy. This general strategy relates systems of vastly different scales, for example black hole physics to information propagation in microscopic quantum systems. UniRand will realize a new, widely applicable approach to measuring global quantum state properties using ultracold atoms. At the heart of the protocol are random unitary transformations, which are applied to a quantum state before measurement. The fluctuating outcomes of measurements under random transformations encode global properties of the density matrix, including Renyi entropies and state overlaps. We are specifically interested in systems of mobile particles in optical lattices. Random unitary protocols will give access to new physics: (1) The dynamics of information scrambling as quantified by out-of-time-order correlators and (2) the order parameter-independent characterization of quantum phase transitions through measurements of fidelity. We will probe both aspects in one-and two-dimensional bosonic Hubbard systems. Our approach will be realized on a new, high-performance quantum simulator that assembles many-body systems from individually laser-cooled atoms with a high repetition rate. Protocols based on random unitaries in ultracold atom systems will open a new toolbox for system-level measurement and enable direct links between quantum information theory and experimental quantum science.

Mots-clés : optical lattices
Projet ERC : GUANTUM (Horizon 2020, appel 2020, Advanced grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Condensed matter physics
Entité participante : Aalto University — Pays : Finlande — Rôle : PI
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 2499033.0 €

Quantum mechanics is a leading success story in science, originally devised to explain matter and energy at the atomic scale. Quantum superpositions and entanglement can produce distinct phenomena unseen in classical physics. Rather recently, such effects have been shown to hold also for macroscopic degrees of freedom, including the motion of somewhat massive objects. However, despite its success at describing phenomena in the low-energy limit, quantum mechanics is incompatible with general relativity that describes gravity and huge energies. The interface between these two has remained experimentally elusive, because only the most violent events in the universe have been considered to produce measurable effects due to the plausible quantum behavior of gravity. Here, we will probe the interface of quantum mechanics and gravity at an unprecedented scale by taking advantage of coupling of microwave fields in cavities and the oscillations of massive micromechanical membranes. We will measure the gravitational force between gold particles weighing a milligram, representing a new mass scale showing gravitational forces within a system. The main goal is to determine the effect of gravity on the quantum evolution of a massive object. We will develop strong quantum measurements in order to reach a situation where the positions of the gravitating masses exhibit significant quantum fluctuations, which includes preparing the gravitating masses in the ground state and in a squeezed state. Our recent work showing mechanical quantum entanglement [Nature 556, 478 (2018)] enables a fascinating goal. With the two oscillators in a two-mode squeezed state, we will create a system that exhibits nonlocal quantum correlations and gravity at the same time, paving the way for directly testing quantum gravity. The project also contributes to technological advances in precision measurements and in quantum information.

Mots-clés : cavity optomechanics
Projet ERC : FLQuant (Horizon 2020, appel 2020, Advanced grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Fundamental constituents of matter
Entité participante : University of Bristol — Pays : Royaume-Uni — Rôle : PI
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 2223065.0 €

Quantum mechanics is fundamentally different from all that came before in almost every aspect. But, as far as I can see now, there is one property that stands above all when we try to understand what quantum mechanics is all about: quantum mechanics is our first theory of Nature that is non-deterministic at a fundamental level. Long considered an unpleasant aspect, non-determinism is anything but: Non-determinism enables new freedoms. Phenomena that could not occur in deterministic theories because they would violate some basic laws of nature become possible in non-deterministic theories, under the cover of randomness. A famous example is nonlocality. In a deterministic world, if something acting in one place would instantaneously produce effects somewhere else, it would violate relativity; non-determinism allows it. As in recent years nonlocality/entanglement came to be viewed as one of the main aspects of nature, and as its existence implies non- determinism but not vice-versa, non-determinism itself was seen as secondary. But non-determinism allows many more freedoms. The vision of this project is to change the paradigm, and put non-determinism at the core. The aim is to go well beyond the insights gained from nonlocality and focus on the other freedoms. It will explore very recently discovered situations with indefinite causal order; situations in which the future can affect the past without leading to paradoxes; evolutions subjected to both initial and final conditions; implications for conservations laws, and thermodynamics, the hitherto ignored dynamic nonlocality, etc. – all fundamental aspects of nature in which non-determinism is the key. Finally, quantum mechanics may not be the ultimate theory of nature. The project aims to explore the full extent of the freedoms allowed by non-determinism in quantum mechanics as well as in arbitrary theories. By comparing what is possible in general to what is specifically quantum, I hope to better understand both.

Mots-clés : quantum mechanics,fundamental aspects,quantum information,time in quantum mechanics,non locality,conservation laws
Projet ERC : FermiSurfaceFlavours (Horizon 2020, appel 2017, Consolidator grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Condensed matter physics
Entité participante : University of Cambridge — Pays : Royaume-Uni — Rôle : PI
Acronyme de l'entité : U. Cambridge
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 2127851.0 €

Quantum oscillations have revealed signature Fermi surfaces in a diverse range of materials families, with breakthrough advances made by a synthesis of theoretical modelling, experimental vision, materials preparation, and advances in measurement technique. Traditionally, the very observation of a Fermi surface has been taken to imply an underlying Fermi liquid. In this proposal, we seek to transcend this traditional paradigm in the field of correlated electron systems and define a new framework for the observation of quantum oscillations associated with a novel Fermi surface in the absence of a conventional Fermi liquid. Guided by a selection of theoretical proposals, we identify for study materials families starting from the more readily modellable correlated Mott insulators and Kondo insulators without the complication of mobile electrons. We progress to regions where mobile electrons are introduced – where we select for study the doped Mott insulating cuprate superconductors. Eventually we access the intervening region of unconventional quantum critical physics where a Fermi surface in the absence of a conventional Fermi liquid transitions to a Fermi surface underpinned by a conventional Fermi liquid, by lattice-density tuning of selected materials. We propose to investigate the Fermi surface of these regimes of correlated materials phase space that defy conventional Fermi liquid behaviour by the use of advanced quantum oscillation techniques in selected high purity correlated materials, under either ambient pressure conditions or under lattice-density tuning, and using high magnetic fields. We expect the project outcome to have a substantive impact on our understanding of correlated electron systems, especially in hitherto opaque regions of phase space where Fermi liquid behaviour breaks down. We thus anticipate a new era where quantum oscillations serve as a diagnostic for novel phases of correlated matter that lack a conventional Fermi liquid description.

Mots-clés : fermi surface,non fermi liquid,spin liquid,quantum critical point,spinons,fractionalized phases,mott insulators,kondo insulators,correlated electrons,quantum oscillations,high magnetic field
Projet ERC : ExQuiSid (Horizon 2020, appel 2017, Advanced grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Condensed matter physics
Entité participante : Technical University of Munich — Pays : Allemagne — Rôle : PI
Acronyme de l'entité : TUM
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 2500000.0 €

Quantum stochastic processes in solids, representing many-body systems par excellence, are believed to lead to extreme forms of quantum entanglement and non-local correlations (extreme quantum matter), that offer a well-defined starting point for an understanding of a wide range of anomalous materials properties, as well as emergent electronic phases such as magnetically mediated superconductivity or partial spin and charge order. While overwhelming experimental evidence clearly suggests a breakdown of traditional concepts such as well-defined quasi-particle excitations, the striking present-day disagreement between experiment and theory may be traced to the lack of experimental information on the spectrum of quantum stochastic many-body processes in solids in the low-energy and low-temperature limit close to and far from equilibrium. ExQuiSid will advance the understanding of the nature of extreme quantum matter in the most extensively studied model systems, notably simple magnetic materials (insulators and metals) tuned through a quantum phase transition. For the proposed studies my group has implemented a new generation of methods covering for the first time neutron spectroscopy with an unprecedented nano-eV resolution even under large magnetic fields, transverse-field vector magnetometry, calorimetry and transport down to milli-Kelvin temperatures, and, ultra-high purity single-crystal growth combined with advanced materials characterisation. ExQuiSid will (i) solve long-standing mysteries in model-systems of extreme quantum phase transitions, (ii) experimentally enable and permit pioneering studies on the creation, nature and classification of non-equilibrium quantum matter in solids at ultra-low energies and temperatures, and (iii) experimentally enable and permit pioneering studies of quantum matter driven periodically out of equilibrium to identify dynamical quantum instabilities and dynamical quantum phases such as many body localisation.

Mots-clés : advanced neutron spectroscopy,low temperature physics,bulk properties,transport properties single crystal growth,quantum phase transitions,quantum materials,emergent phenomena,topology
Projet ERC : ECLIPSE (Horizon 2020, appel 2019, Starting grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Condensed matter physics
Entité participante : ARMINES — Pays : France — Rôle : PI
Acronyme de l'entité : ARMINES
Type d'entité : Recherche
Financement ERC de l'entité : 1178875.0 €

Quantum systems can occupy peculiar states, such as superposition or entangled states. These states are intrinsically fragile and eventually get wiped out by inevitable interactions with the environment. Protecting quantum states against decoherence is a formidable and fundamental problem in physics, which is pivotal for the future of quantum computing. The theory of quantum error correction provides a solution, but its current envisioned implementations require daunting resources: a single bit of information is protected by encoding it across tens of thousands of physical qubits. My proposal is to protect quantum information in an entirely new type of qubit with two key specificities. First, it will be encoded in a single superconducting circuit resonator whose infinite dimensional Hilbert space can replace large registers of physical qubits. Second, this qubit will be rf-powered, continuously exchanging photons with a reservoir. This approach challenges the intuition that a qubit must be isolated from its environment. Instead, the reservoir acts as a feedback loop which continuously and autonomously corrects against errors. This correction takes place at the level of the quantum hardware, and reduces the need for error syndrome measurements which are resource intensive. The circuits I will develop manipulate quantum states of light, whose utility transcends the long term goal of quantum computing, and can readily be used to probe fundamental properties of matter. In mesoscopic physics where a large number of particles exhibit collective quantum phenomena, the measurement tools to characterize subtle quantum effects are often lacking. Here, I propose to measure the spin entanglement of a single Cooper pair, by coupling a superconductor to a circuit composed of microwave resonators and a carbon nanotube. The spin entanglement can be swapped into microwave photons, which can be detected by deploying the arsenal of quantum limited microwave measurement devices.

Mots-clés : superconducting circuits,quantum error correction,quantum sensing,josephson junctions,carbon nanotubes
Projet ERC : PEDESTAL (Horizon 2020, appel 2019, Advanced grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Fundamental constituents of matter
Entité participante : University of Cambridge — Pays : Royaume-Uni — Rôle : PI
Acronyme de l'entité : U. Cambridge
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 2478734.0 €

Quantum technologies promise revolutionary capabilities in processing information and transmitting with security over a network certified by the principles of quantum physics. The key hardware element of a quantum network is the ‘node’, where a stationary qubit cluster perform primitive processes and communicate with other nodes by exchanging flying qubits. The interfacing between the stationary qubit cluster and the flying qubits is realised by a special ‘broker qubit’. Today, the most competitive candidates for flying and stationary qubits are photons and diamond spins, respectively, and this opportunity is being pursued worldwide. A specific emitter in diamond, the Nitrogen Vacancy (NV), has enabled landmark demonstrations of basic quantum building blocks, but faces fundamental challenges on reaching the optical qualities required to scale up. PEDESTAL offers an efficiency boost to the NV while building on key advances in diamond technology. Our goal is to create a quantum node hardware prototype with characteristics required to sustain a multi-purpose quantum network capable of implementing simultaneous quantum communications and computing. PEDESTAL will develop a demonstrator quantum node based on diamond group-4 spins, which offer specifications outperforming others. Benchmarking against the known silicon-vacancy (SiV) centre, our workhorse will be the tin-vacancy (SnV) centre, which we have shown to have outstanding qualities satisfying the requirements for a quantum node. In parallel, we will develop to maturity the less-known but highly promising lead-vacancy (PbV) centre which can operate with more feasible conditions and develop a novel technique to control spins. Our objectives include creating multi-spin and multi-photon entangled states as resource and will complete its key objectives with the demonstration of distributed three-spin entanglement, culminating in the experimental demonstration of a high-fidelity, high-bandwidth multi-node quantum network

Mots-clés : quantum optics,diamond,spin qubit,photons,photonic qubit,entanglement,cluster states
Projet ERC : PRIMES (Horizon 2020, appel 2019, Starting grants)
Domaine scientifique : Physical Sciences and Engineering
Panel : Mathematics
Entité participante : University of Oxford — Pays : Royaume-Uni — Rôle : PI
Type d'entité : Enseignement supérieur ou secondaire
Financement ERC de l'entité : 1489402.0 €

Questions about prime numbers make up several of the oldest and most important open problems in mathematics. Unfortunately our techniques for solving these problems are very limited; even some of the most basic and simple to state questions about primes are well beyond current techniques. This project studies several different questions related to the distribution of the primes, with the aim of developing new flexible techniques for studying the primes in general. Such new techniques would then give insight to the fundamental problems at the heart of the subject. The only general approach we have to counting primes is via variants of ‘Type I’ and ‘Type II’ arithmetic information. There have been several remarkable developments in sieve methods in recent years, which have greatly enhanced the utility of Type I information. Without establishing some sort of Type II information, however, it seems unlikely that one can fully solve the most important problems in the subject. This proposal seeks to develop both our Type I techniques and our Type II techniques, as well as the interactions between them. A common theme throughout the proposal is to identify and classify potential obstructions to traditional methods, and then overcome these obstructions using a combinations of new ideas. Often these new ideas will come from other areas of mathematics, such as combinatorics, geometry, probability, automorphic forms or harmonic analysis. This approach has already led to significant advances in our understanding of primes in recent years, most notably in the gaps between primes. The proposal is based around several intermediate problems for developing these connections further, giving opportunities for proof-of-concept results of such new ideas overcoming old barriers.