« Information is physical » : by postulating the physical nature of information in 1961, Landauer was solving the paradox of Maxwell’s demon and successfully merging thermodynamics and information sciences. Of particular relevance is Landauer’s limit, which sets the smallest possible amount of work necessary to erase one bit of information, whereas reversibly, one bit of information can be converted into useful work (Szilard’s engine). Later in the nineties, the developments of quantum information shed novel light on entanglement, which appeared as a resource allowing to communicate more securely and to compute more efficiently than in the classical world. Recently, the peculiarities of quantum information started to be explored within a thermodynamical paradigm. Oddly enough, it was shown that the erasure of a bit could produce work provided that the observer is quantum, a drastic difference with respect to classical information. Owing to the progresses of nanotechnologies, Landauer’s limit and Szilard’s engine have recently been experimentally demonstrated with classical bits. However, thermodynamics of quantum information has remained restricted to theoretical investigations so far, involving rather abstract notions of small systems, thermal baths and batteries. The purpose of the present project is to give a physical identity to these notions, and to suggest and model experiments in this new field, in close interaction with experimental groups. Feasibility studies will be conducted for two different systems, both having already shown outstanding results in the domain of quantum information processing, namely Josephson qubits in circuit QED (case 1) and solid-state emitters in optomechanics (case 2). As a first step, we will build the conceptual and modeling tools to describe a heat engine operating at the single quantum level. We will particularly focus on extensively characterizing the work produced by the machine, that will either consist of tiny electromagnetic (case 1) or phononic fields (case 2). This is drastically new with respect to former estimations of the thermodynamical quantities, so far based solely on measurements performed on the small working system itself. This approach relies on the ability to monitor continuously such environments as transmission lines or phononic fields, an ability that we plan here to exploit for the first time in a thermodynamical context. This study should lead to the first direct measurement of Landauer’s limit. As a second step, we will study the potential of each system as a platform to investigate new physical effects related to quantum information and entanglement. In this perspective, heat engines involving two quantum bits will be modeled. In particular, we will explore to which extent the useful energy extracted from the engine can be used to quantify the strength of the correlations between the two qubits. A final product of these fundamental investigations could be a heat engine working as entanglement witness. The success of the present project will contribute to create an important synergy between a wide range of scientific communities : quantum optics, quantum information, thermodynamics, circuit QED and optomechanics. It will benefit from the collaboration with a high level team working on theoretical aspects of the thermodynamics of quantum information, and aims at developping a local think tank around these groundbreaking ideas, in direct connection with experimentalists. From a deeper point of view, this project will bring out the first building blocks for the comprehension of information/energy conversion at the nanoscale, a fundamental issue in our society of information.

Devices based on the control of quantum states will revolutionize information and communications technologies. It is now possible to fabricate and isolate individual quantum objects that can be prepared in any superposition of quantum states. Several implementations of the quantum bit (Qubit), i.e. the building block for systems targeting quantum-enabled functionalities, were already demonstrated. Approaches based on all-superconducting materials provide the most advanced solid-state platform to date but one of their drawbacks is that they must rely on magnetic effects for control and operation, which is not an industry standard for devices. This starts already to be an issue in large scale circuits. On the other hand, approaches fully based on semiconductors provide spin Qubits with long coherence times that are electrically tunable and addressable. They are very promising for large scale integration because they are based on mainstream industry technologies. But fast quantum state readout will require their co-integration with superconducting resonators. To bridge the gap between these two approaches, I propose the integration of a gapless two-dimensional semiconductor, graphene, in the key element of superconducting quantum circuits: the Josephson junction, a weak link between two superconducting electrodes. It will create an electrically tunable Josephson element. The resulting quantum circuits will gain electrical tunability, a breakthrough for control and future integration. Assisted by a strong theoretical support, several pivotal elements of quantum technologies will be demonstrated during the project: an electrically tunable Qubit, an electrically pumped quantum limited Josephson parametric amplifier and an electrically controlled coupler between Qubits that will be a major step for future scaling. Beyond those demonstrations, the unique properties of a graphene based Josephson element will be used to build a topologically protected Qubit, i.e. a Qubit that is intrinsically immune to decoherence, an outstanding problem in quantum computation. Graphene, which can now be grown on wafer scale while maintaining high electron mobilities, is only one atom thick and can be combined in a simple manner with mainstream technologies by using recently developed transfer techniques. This is a fundamental asset for future developments and a clear advantage compared to competing technologies based on III-V semiconductor nanowires or two-dimensional electron gas.

A tremendous goal of nowadays is to understand how brain works in health and disease. Following the electrical activity of such dense and intricate networks (billions of connected neurons), without damaging it, is highly challenging. It requires biomimetic materials to face the reject of the foreign analog probe, reliable nanosensors for localized detection of microscopic events sustaining neural activity, and specific optical or chemical stimulation to interrogate neurons by many means. For that, this proposal aims to implement novel graphene neuroelectronics on a unique highly biocompatible and multimodal neural probe enabling bi-directional communication with target networks. Beside the fundamental interest, such chronic and high spatio-temporal mapping of neurons activity would be useful for the next generation of neuroprosthesis to replace and restore disable functionality lost after injury, trauma or neurodegenerative disease, with strong impact in electrophysiology and pharmacology

Conjugated organic molecules and polymers hold a great potential for flexible, cheap and eco-friendly (opto)electronics. This project has the ambition to provide a fundamental contribution to overcome existing bottlenecks currently hampering the widespread application of organic semiconductors, such as the modest charge mobility of molecular crystals or the limited understanding of the mechanism for molecular doping. In a field mostly driven by serendipitous approaches, RAPTORS instead proposes a powerful and original multiscale and inter-disciplinary modeling approach synergistically combining molecular modelling techniques, state-of-the-art first principles calculations, and effective models targeting phenomena at the macroscopic scale. This comprehensive approach is explicitly designed to attain structure-property relationships and it ultimately aims at the disclosure of rational design rules for new materials with improved properties. Such a global strategy, will be applied to develop two complementary research axes: (i) The search for the next generation of high-mobility molecular semiconductors, to be pursued with a smart high-throughput computational screening of existing and yet-to-be-made compounds, built around the emerging “transient localization” framework for phonon- limited transport in soft van der Waals solids; (ii) The establishment of a reference theory for molecular doping, capable to rationalize the transition to conducting states at finite impurity concentrations, and to provide a unifying framework for p- and n-type doping in molecules and polymers, encompassing chemical and morphological aspects. Special emphasis will be given to many-body dielectric screening phenomena that are at core of other insulator-metal transitions, and that have been not considered in the context of molecular doping to date. This research will be undertaken in close collaboration with a team of leading theoretical and experimental partners with complementary expertise, levering the ambitious scientific profile of the project, and fostering the French and European excellence in organic electronics fundamental and applied research.

The SOCQS project aims at investigating a new class of materials displaying unconventional magnetism, called Kitaev physics. Kitaev materials are predicted to harbour a new exotic state of matter, known as quantum spin liquid, along with fractional excitations appealing for quantum computation applications. In this context, this project proposes to explore this new class of materials through the study of cobalt-based magnetic oxides, which have been recently identified as prime candidates for exhibiting Kitaev physics. The project aims at understanding the underlying mechanisms associated to Kitaev physics and achieving the quantum spin liquid groundstate in these materials through the manipulation of external parameters. To tackle this experimental challenge, the applicant will federate a team of researchers with complementary expertise. The SOCQS project is a first step for the applicant to develop of this novel topic of research within her team, as a new recruit at CNRS.