Horaire

What is the world made of? A journey into the infinitely small.

More than 50 years of experimentation has led to the development of a coherent picture of what matter is made of at the smallest distance scales. All matter in the Universe appears to be made of elementary particles that can undergo a well-defined set of interactions. 

In this talk, I will first summarize our current knowledge of particle physics and then describethe mysteries that remain. Ongoing and future experiments designed to provide insights into some of these mysteries of the Universe will be presented. Rapid technological developments continuously open the door to new research avenues, such that important breakthroughs are expected in the coming years. This is an exciting time for particle physics research!

Ultrasound-activated nanostructures for cancer imaging and therapy

Imaging is a fundamental tool in the practice of medicine. In parallel with the development of improved imaging systems and techniques, there is increasing interest in designing new contrast agents that can help guide and assess personalized treatment for cancer patients. A new opportunity in materials science is the development of new injectable materials that can be both tracked using medical imaging and remotely activated from outside the patient to treat cancer.

This talk will focus on the development of ultrasound-activated contrast agents that can facilitate more focused and targeted delivery of cancer therapies to tumours towards the ultimate goal of improving outcomes for cancer patients. Specific examples of contrast agents that are assembled to address and balance biological and physical challenges of contrast agent development will be given, with a focus on the use of perfluorocarbon bubbles and droplets for ultrasound imaging and therapy applications.

La formation stellaire dans les galaxies telle que vue par SITELLE.

Le développement de nouveaux instruments astronomiques est un élément clé des avancées scientifiques. En créant SpIOMM et SITELLE, deux spectro-imageurs à transformée de Fourier, le Québec se démarque de par son ingéniosité. J’utilise présentement SITELLE, au Télescope Canada-France-Hawaii pour observer les régions des galaxies voisines où de nouvelles étoiles se forment. Les étoiles jeunes et massives chauffent le milieu qui les entoure et ionisent le gaz interstellaire. Nous allons voir au cours de cette présentation comment il est possible d’analyser la lumière qui est émisse autour des sites de formation stellaire par le gaz ionisé pour comprendre la physique interne de ces régions. Un tel travaille serait impensable sans SITELLE.

Applying Physics to Air Quality & Climate Problems

This talk will begin with an overview of the role that physics plays in interdisciplinary research into some major environmental issues facing humanity today:  air quality, climate change, and ozone layer depletion and recovery.  Next, I will discuss my current research in remote sensing of atmospheric composition as applied to a problem of marine shipping pollution emission and dispersion in Halifax, Nova Scotia.  Finally, I will touch on some frontiers of atmospheric environmental physics (e.g., detection and attribution of anthropogenic climate change, and land-atmosphere gas exchange).

Earth : une carte mondiale des conditions de vent, météorologiques et océaniques : https://earth.nullschool.net/fr/

Nanoelectronic sensors for biological molecules

Our research focuses on the design and application of ultraminiaturized electrical circuits able tocapture and probe individual biomolecules, in real time and over a wide range of timescales. Such nanosensors allow to follow, through fluctuations in electrical conductance, successive chemical eactions and conformational changes occurring on ensemble or isolated biomolecules. I will present recent strategies for assembling such sensors using carbon nanotubes and graphene, as well as experiments based on this approach to explore the conformational and hybridization dynamics of DNA sequences. Finally, I will discuss our plans to expand this emerging technique towards other biomolecular mechanisms and lab on a-chip biomedical technology.

Quantum Materials for Topological Quantum Computation (tentative)

Quantum computers create exponentially greater processing power but their qubits made of electrons or photons suffer from decoherence. Topological quantum computation refers to error-correcting quantum codes protected from decoherence. This requires a long-range entanglement and fractionalized particles obeying nontrivial statistics. These so-called anyons may emerge from strong electron-electron interactions, and exactly solvable mathematical models for topological quantum computation have been known for a while. However, their realization in solid-state materials has not been clear until very recently. I will present a brief historical review and discuss how to search for strongly correlated topological materials.

What should you do with quantum-dot doped composites, an atomic clock and a frequency comb interferometer?

The most counter-intuitive ideas of quantum theories, such as superposition and entanglement, are progressively becoming common place in many physics laboratories thanks to designer materials and extraordinary instrumentation. I will present our research efforts into improving quantum optical systems towards technologies that could even become part of your everyday life. 

Semiconductor nanocrystals now allow us to actuate the textbook problem of the particle-in-a-box in almost any shape, overcoming the atomic potential and periodic table constraint, thus earning the name colloidal quantum dots. Challenges still occur in perfecting their interaction with light in order to produce indistinguishable single photons on demand, so we investigate the effect of embedding these quantum dots in polymers with the goal of drawing such composite materials into optical fibers. The Purcell effect can then accelerate the radiative transition dynamics thanks to confined electromagnetic field interacting with the quantum dots. However, precise metrology tools such as atomic clocks are needed to quantify the changes expected on the shortest time scales. I will therefore conclude the presentation on our adaptation of pump-probe spectroscopic techniques to state-of-the-art frequency comb interferometry.

‘Cool’ transistors: When devices from microelectronics industry become quantum!

Silicon transistors are widely used throughout our everyday life. Our need for always faster and more powerful devices has driven a dramatic scaling down in the size of individual transistors such that transistors become very sensitive to a single atom’s displacement and to quantum effects at low temperature. I will show how this apparent current limitation in reality opens up an entire new era: Quantum Nanoelectronics, where the bit of information is now encoded in the spin instead of the charge and devices are governed by the laws of quantum mechanics. I will show how these transistors, performing at low temperature, could become the building blocks for powerful quantum computation.