PhD Portrait : Jean Olivier Simoneau

Curious by nature, attracted by the world of computer science and by science, Jean Olivier developed a strong interest in these fields, to the point of deciding to opt for physics to continue his studies in university.

He therefore travelled the distance that separates him from his native Abitibi by choosing the Université de Sherbrooke. Why this choice? “A CEGEP professor, Jérémie Belzil, who graduated from Sherbrooke in physics, told me about the possibility of doing internships and being from Abitibi, I was drawn to the proximity to nature. These two things convinced me,” explains the PhD student.

During his first semesters, Jean Olivier worked with Professor Denis Morris in optics to manufacture terahertz antennas, then with Professor Bertrand Reulet on a noise amplifier. It is also the latter who will guide him to a final internship, this time in France, mainly devoted to the nanofabrication of samples.

Master’s Degree

Without hesitation, the researcher jumped at the opportunity to pursue his master’s projects with Bertrand Reulet.

“In Bertrand’s group, we are interested in noise, in electronic fluctuations. This is often something people want to eliminate because it obscures the signal they want to see, but noise is fundamental. Gabriel Gasse, who studied for his master’s degree in Bertrand’s group, demonstrated a signature squeezing, which allows noise to be crushed and dropped below the quantum limit. This phenomenon is linked, in optics, to the emission of pairs of entangled photons. By making some measurements of electron fluctuations, we can extract the same photon statistic. These quantities are related because a photon is a fluctuation in the electromagnetic field and electronic noise is also associated with such fluctuations. So, I measured the statistics of microwave photons emitted by a tunnel junction that ‘squeezes’, and which should therefore emit pairs. We actually observe the signature of the pairs within the photon statistic obtained by this method.”

Quantum Optics

With this perspective on electronic fluctuations in mind, Jean Olivier moved on to his doctorate, focusing on a sample used during his master’s, a Josephson parametric amplifier. With this approach, the researcher demonstrated that the statistics of the photons emitted by this sample were indeed those expected, in addition to highlighting the impact of the detection scheme of the results. This research was recently submitted for publication.

“The change of sample brought a lot of calibration work. For the PhD, we used a Josephson parametric amplifier directly, an amplifier that is at the quantum limit and can amplify as much as physics allows.”

Tunnel Junctions

Jean Olivier’s second project concerns tunnel junctions. Two pieces of metal separated by an oxide (insulator) on which electrons tunnel from one rod to another. This sample must be placed at a very low temperature to observe quantum phenomena.

“The energy scale of frequency must be greater than that of temperature. The measurement is then taken for a given frequency. We had access to equipment which made it possible to measure voltage points in time in a very wide band at a rate of 32 billion times per second and to have direct access to the trace. All of these points allow us to extract a lot of information, including autocorrelation. The equipment was able to synchronize the excitation, which allowed us to obtain phase-resolved correlations. We put together a simple assembly that provided a phenomenal amount of data and information.”

Managing such a large amount of data was not necessarily an obstacle for Jean Olivier, it was in fact a great source of motivation. His passion for computer science served him well, and he tackled the challenge of programming for data processing.

Related Tasks

During his career, Jean Olivier also gave several exercise sessions as well as laboratories, especially in classical mechanics as well as some advanced practical work. He has also often turned himself into a guide for those interested in visiting Professor Reulet’s laboratory, in addition to teaching the quantum physics course for engineers at the Faculty of Engineering with his colleague Édouard Pinsolle.

Pr Reulet has greatly appreciated working with Jean Olivier: “Jean Olivier is a dedicated person who likes to share his passion, whether with colleagues, students or anyone who comes his way. It was a privilege and a great pleasure to have him in my group. Many times, he shared with us his knowledge in physics, computers as well as cooking! On behalf of the whole group, thank you JO!”

Starting His Career in the Industry

Having finished his university career, Jean Olivier admits that he did not plan for research or teaching objectives. On the contrary, he prefers to take advantage of the opportunities available to him at the moment, which is why he joined the ranks of the young company Nord Quantique since October 2020.