Robust Superconducting and hybrid Quantum bits
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Welcome to Armelle Celarier who started a CIFRE thesis:
Quantum bits are prone to two types of errors due to uncontrolled interactions with their environment. To build a quantum computer, these errors must be reduced while maintaining the ability to control the qubit. In my PhD, I work with cat qubits, superconducting qubits whose bits are encoded in coherent states of a harmonic oscillator with opposite phases. To stabilize such states, we use a driven-dissipative scheme, where photons are exchanged in pairs with the environment. This kind of qubit is very interesting as it can be in a regime where one of the two types of errors is suppressed (noise bias qubit). To remove the other errors, the strategy is to encode the information redundantly across several qubits and regularly measure them to detect and correct the errors (quantum error correction).
To perform error correction, one needs a gate between two qubits which is called the CNOT. Depending on the state of the first qubit (control), a “NOT” operation is performed or not on the second qubit (target), corresponding to flipping the 0 to 1 and 1 to 0. The goal of my PhD is to experimentally implement such a gate in a way that doesn’t break the noise bias of the cat qubit. In other words, the CNOT gate should not reintroduce the error against which cat qubits are inherently protected.
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This project is done at LPENS under the supervision of Zaki Leghtas, with Adrien Bocquet and in partnership with Alice & Bob (CIFRE PhD).
Superconducting circuit enabling the manipulation of a Schrödinger cat qubit
@N.Hoppenot/ENS Lyon
ABOUT
The RobustSuperQ project aims at accelerating French R&D on superconducting and hybrid qubits protected by construction against decoherence. It is part of a post-transmon strategy, alternative to surface code, in which the French teams are at the forefront. It brings together all of these teams around three complementary concepts: the Cat-code architecture, spin qubits implanted on superconducting circuits, and topologically protected superconducting qubits.
RobustSuperQ is a PEPR,
a priority programme for research and equipment, part of the French Quantum Plan
WHAT WE DO
Assembling a superconducting circuit in cavity
@N.Hoppenot/ENS Lyon
We accelerate the French R&D on robust superconducting and hybrid qubits protected against decoherence. The project is organized into work packages (WP)
- WP0: Bricks of components and methods for WP1, 2 and 3.
- WP1: Cat-qubits encoding information in quantum superpositions of coherent microwave states.
- WP2: Dopant Spin qubits, encoding information in electronic and nuclear spins.
- WP3: Development of new qubits with topological protection.
- WP4: Creation and modernization of two manufacturing platforms* for superconducting qubits, and project coordination.
*Platforms: The two technical poles in the field, Ile-de-France and Grenoble, will make a qualitative leap in terms of resources, via the creation at CEA-Université Paris-Saclay of a new dedicated platform, and the acquisition of fabrication and characterization tools in the two poles. The resources will be pooled and interoperable, and the synergy of know-how and associated processes will be maximized.