Jean-Claude Besse

Jean-Claude Besse's research


I work on the fabrication of superconducting circuits, and quantum optics in the microwave domain using artificial atoms (see About).

Main work

The results of my main projects as a PhD candidate:

Entangled light modes

Quantum optics crucially relies on sources of quantum states of electromagnetic radiation. In this work, we demonstrate a source of entangled modes of microwave radiation that is fully deterministic, coherent, versatile, and scalable. Full quantum state tomography is performed up to 4 modes, and process maps of the sequential emission process allow us to find entanglement lengths of order ten photonic qubits.

Parity detection

Parity is an important statistic of physical systems. Here, we go beyond single photon detection and measure the parity of radiation reflected from a detector in single shot. We showcase the parity measurement on Fock states, demonstrate direct Wigner tomography of itinerant quantum light fields, and generate Schrödinger cat states.

Single photon detection

Information is often transmitted using electromagnetic radiation, the quantum units of which are photons. In the microwave regime, detecting single itinerant photons at the receiving end of a transmission channel is challenging since microwave photons possess 5 orders of magnitude less energy than their optical counterparts. In this work, we show how to transfer the information content of a propagating photon into an excitation of a stationary qubit. By reading out the state of the latter, we acquire knowledge about the photon’s presence without destroying it. This ‘non-demolition’ aspect opens up new possibilities of detecting the photon in flight while allowing it to travel on towards another destination.

Side projects

Other projects I've been involved in:

Interacting photons

Realization of a universal quantum gate set for itinerant microwave photons.

Tunable ZZ gate

A two-qubit C-PHASE gate implemented with tunable ZZ interactions.

Primary Thermometry

A primary thermometer for microwave transmission lines, requiring only a very basic setup.

2-Photon Fluorescence

A study of two-photon resonance fluorescence, and Mollow-like triplets, by driving an artificial atom at the two-photon transition between its ground and second-excited state.

Photon Ordering

A system of two driven-dissipative nonlinear resonators, showing a crossover between an ordered state and a delocalized phase of photons.

Cascade Decay

How cascade decay of a ladder-type 3-level atom leads deterministically to entangled photon pairs, that we can spatially separate.

Superconducting Switch

A superconducting switch, able to route quantum fields on chip with low loss, fast switching time, and high compression point.

Fab contributions

My work, mostly in the clean room, also supported:

Microwave Quantum Link

Remote entanglement between two superconducting chips housed in separated cryogenic systems.

fg-ge gate

An all-microwave gate between two far detuned superconducting qubits.

Time-bin Encoding

Loss detection in quantum communication via time-bin encoding of information.

Entanglement Stabilization

Ancilla-based parity measurement, and real-time feedback, demonstrating entanglement stabilization.

Multiplexed Readout

High-fidelity, low crosstalk, fast, readout of up to 5 superconducting circuits in a multiplexed circuit.

All Microwave Reset

A fast, unconditional, all-microwave reset of superconducting qubits.

Remote entanglement

Deterministic remote entanglement between two superconducting atoms based on separate chips.