Description du projet
Un nouveau type de qubit pour une protection de l’information quantique moins gourmande en ressources
Les systèmes quantiques peuvent exister dans des états fragiles qui sont finalement anéantis par les interactions avec l’environnement. Protéger de tels états est essentiel pour l’avenir de l’informatique quantique. Bien que la correction des erreurs quantiques constitue une solution, elle nécessite d’énormes ressources. Le projet ECLIPSE, financé par l’UE, entend s’attaquer à ce problème en protégeant les informations quantiques dans un nouveau type de qubit qui présente deux spécificités essentielles. Premièrement, le codage se fera dans un résonateur à circuit supraconducteur unique dont l’espace de Hilbert à dimension infinie est susceptible de remplacer de grands registres de qubits physiques. Deuxièmement, ce qubit sera alimenté par fréquence radio et échangera continuellement des photons avec un réservoir. Les circuits mis au point permettront de manipuler les états quantiques de la lumière. Ces travaux pourraient faire progresser la protection des informations quantiques dans les systèmes quantiques de demain.
Objectif
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.
Champ scientifique
- natural sciencesmathematicspure mathematicsalgebralinear algebra
- natural sciencesphysical sciencescondensed matter physicsmesoscopic physics
- engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringcomputer hardwarequantum computers
- natural sciencesphysical scienceselectromagnetism and electronicssuperconductivity
- natural sciencesphysical sciencestheoretical physicsparticle physicsphotons
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Programme(s)
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Régime de financement
ERC-STG - Starting GrantInstitution d’accueil
75272 Paris
France