May 27, 2026 10:55 AM
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May 28, 2026 4:30 PM
May 27, 2026 10:55 AM
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May 28, 2026 4:30 PM
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Hôtel Château Bromont
Hôtel Château Bromont
Opening Remarks
Pr Mathieu Juan, Institut quantique - Université de Sherbrooke
Clasical and quantum computations as tensor networks
Pr Stefanos Kourtis, Institut quantique - Université de Sherbrooke
Classical and quantum computations as tensor networks
Break
Event organized in collaboration with the RQMP and animated by Mrs. Chloé Freslon, founder of URelles
Falisha Karpati, Ph.D.
Think Differently Together: Strengthening research and innovation by embracing cognitive diversity
Louis-Philippe Lamoureux (Slides / Présentation)
Thierry Debuischert, Thales - France (postponed to Monday at 13:15 / reporté à lundi 13h15)
Closing remarks of the day
Opening remark of the day
Thierry Debuischert, Thales - France
Professor Tami Pereg-Barnea, McGill University
Dynamic topology - quantized conductance and Majoranas on wires
Professor Philippe St-Jean, Université de Montréal
Topological physics with light and matter: new horizons
Break
Louis Gaudreau, National Research Council Canada (Ottawa)
Entanglement distribution via coherent photon-to-spin conversion in semiconductor quantum dot circuits
Philippe Lamontagne, National Research Council Canada (Montréal)
Black-Box Impossibility in the Common Reference Quantum State Model
Olivier Gagnon-Gordillo, Québec quantique lead
Presentation of the Québec Quantum ecosystem
Institut quantique - Université de Sherbrooke
Classical and quantum computations as tensor networks
Tensor networks are multilinear-algebra data structures that are finding application in diverse fields of science, from quantum many-body physics to artificial intelligence. I will introduce tensor networks and illustrate how they can be used to represent classical and quantum computations. I will then motivate tensor network algorithms that perform or simulate computations in practice and demonstrate their performance on benchmarks of current interest, such as model counting and quantum circuit simulation. I will close with an outline of ongoing work and an outlook on future directions.
Institut quantique - Université de Sherbrooke
Optomechanics with a non-linear cavity
The possibility to operate massive mechanical oscillators close to or in the quantum regime has become central in fundamental sciences. LIGO is a prime example where quantum states of light are now used to further improve the sensitivity. Concretely, optomechanics relies on the use of photons to control the mechanical motion of a resonator, providing a path toward quantum states of massive objects and for the development of quantum sensors. In order to improve this control many approaches have been explored, some more complicated than others. In particular, in order to cool the mechanical motion a cavity can be used to realise side-band cooling. In general, linear cavities are favoured to allow for large photon number providing stronger cooling. I will show that, surprisingly, non-linear cavities can be used to achieve very efficient cooling at low powers. Indeed, even in the bad cavity limit, we have been able to cool a mechanical resonator from 4000 thermal phonons down 11 phonons. Currently limited by flux noise, this approach opens promising opportunities to achieve quantum control of massive resonators, an avenue to study foundational questions.
McGill University
Dynamic topology - quantized conductance and Majoranas on wires
This talk will address the issue of out-of-equilibrium topological systems. While many materials and devices produced in labs today are topological at equilibrium, it is desirable to have a knob to tune or induce topological properties. For example, if we could dynamically turn a superconductor into a topological superconductor we may create the sought after Majorana fermions which are potential building blocks of quantum bits.
In this context we will explore the possibility of perturbing quantum systems using time-periodic fields (i.e., radiation) and use the Floquet theory to characterize the driven states. We find that in topological systems, beyond the expected splitting of the spectrum into side bands, a change in the topology may occur. In the case of a topological superconductor, the driven system may develop new Majorana modes which do not exist at equilibrium and can be exchanged on a single wire. A protocol for exchanging Majoranas will be presented.
Université de Montréal
Topological physics with light and matter: new horizons
Topology is a branch of mathematics interested in geometric properties that are invariant under continuous deformation, e.g. the number of holes in an object. In the early 1980s it was demonstrated that similar topological properties can be defined for solids presenting appropriate symmetry elements. The discovery of these topological phases of matter has profoundly impacted our understanding of condensed matter, its influence ranging from better explaining the universality of the conductivity plateaus in the quantum Hall effect to developing new platforms for fault-tolerant quantum computation[i]. In the late 2000s, Duncan Haldane (co-laureate of the Nobel Prize in physics for the discovery of topological phases of matter) demonstrated that this topological physics is not restricted to condensed matter but can also emerge in artificial systems like photonic crystals through a careful engineering of their symmetry properties[ii]. Since then, these photonics platforms have proven to be an amazing resource for pushing the exploration of topological matter beyond what is physically reachable in the solid-state, leading to the emergence of a blooming field called topological photonics[iii].
In this presentation, I will describe recent experimental works based on exciton-polaritons, a hybrid light-matter quasiparticle, which have opened new horizons in topological photonics[iv]. The main advantages of polaritonic systems arise from their dual nature: their photonic part allows for tailoring well-defined topological properties in lattices of coupled microcavities and makes them inherently non-hermitian; on the other hand, their matter part gives rise to a strong Kerr-like nonlinearity and to lasing[v]. I will then discuss in more details a recent work in which we took profit of these assets to experimentally extract topological invariants - a fundamental quantity in topology - in a polaritonic analog of graphene[vi]. Importantly, this has allowed us to directly probe the topological phase transition occurring in a critically strained lattice - i.e. where Dirac cones have merged - a condition impossible to reach in the solid-state. I will conclude this presentation by discussing how topological protection can provide a powerful asset for generating and stabilizing many-body quantum states of light and matter. Such mesoscopic quantum objects are highly desirable as they would provide an extended playground for quantum simulation, sensing applications or for generating exotic states of light such as many-body entangled states[vii].
[i] M. Z. Hasan and C. L. Kane. Rev. Mod. Phys. 82, 3045 (2010)
[ii] F. D. M. Haldane and S. Raghu. Phys. Rev. Lett. 100, 013904 (2008)
[iii] T. Ozawa et al. Rev. Mod. Phys. 91, 015006 (2019)
[iv] D. D. Solnyshkov, G. Malpuech, P. St-Jean et al. Opt. Mat. Express 11, 1119 (2021)
[v] I. Carusotto and C. Ciuti. Rev. Mod. Phys. 85, 299 (2013)
[vi] P. St-Jean et al. Phys. Rev. Lett. 126, 127403 (2021)
[vii] P. Lodahl et al. Nature 541, 473 (2017)
Think Differently Together: Strengthening research and innovation by embracing cognitive diversity
This talk will cover:
Biography
Falisha Karpati, PhD is a neuroscientist turned inclusion consultant. Falisha’s work focuses on using neuroscience to build inclusive environments in academic, research, and scientific organizations. Her approach to inclusion centres on the interconnectedness of cognitive, demographic, and experiential diversity. Prior to starting her consultancy practice, she worked as the Training and Equity Advisor for Healthy Brains, Healthy Lives at McGill University.
Head of Applied Quantum Physics
Thales Research & Technology
Researcher
National Research Council Canada (Ottawa)
In this talk, I will present our proposed long distance entanglement distribution scheme that aims to overcome fundamental limitations present in current optical schemes. By using direct band gap semiconductor quantum dots, efficiency and heralding advantages can be exploited through photon-to-spin conversion. For this reason, materials such as GaAs are superior to Si in this type of applications. I will review current schemes to transfer polarization or time-bin encoded photonic qubits to electron spin qubits and will describe adaptations to employ heavy holes which have a number of attractive properties including g-factor tunability. Finally, I will show preliminary results on quantum dot devices using Van der Waals heterostructures which present several potential advantages such as higher confinement energies due to their atomically thin geometry, easier combination with different substrates and the possibility of encoding information in their valley degree of freedom.
Biography
Louis Gaudreau studied physics at Sherbrooke University, followed by a masters and PhD in co-supervision with Andrew Sachrajda at NRC and Alexandre Blais at Sherbrooke. During his graduate studies, Louis studied electrostatic quantum dots and realized for the first time a coupled triple quantum dot system leading to the investigation of the first exchange-only qubit. During this period he was invited to perform quantum dot experiments in Stefans Ludwig’s group at LMU in Munich. After his PhD, Louis changed fields and studied light-matter interactions by combining quantum emitters and graphene to create different hybrid systems. These experiments were done during his postdoc at ICFO in Barcelona in the nano-opto-electronics group with Frank Koppens where he was awarded the prestigious Marie-Curie fellowship. Finally, since 2015, Louis has worked as research officer at the NRC where he investigates different technologies linked to quantum information.
Researcher
National Research Council Canada (Montréal)
Black-Box Impossibility in the Common Reference Quantum State Model
We explore the cryptographic power endowed by arbitrary shared physical resources. We introduce the Common Reference Quantum State (CRQS) model, where the parties involved share a fresh entangled state at the outset of each protocol execution. This model is a natural generalization of the well-known Common Reference String (CRS) model but appears to be more powerful. In the two-party setting, a CRQS can sometimes exhibit properties associated with a Random Oracle queried once. We formalize this notion as a Weak One-Time Random Oracle (W1TRO), where we only ask of the output to have some randomness when conditioned on the input is still beyond the reach of the CRQS model. We prove that the security of W1TRO cannot be black-box reduced to any assumption that can be framed as a cryptographic game. Our impossibility result employs the simulation paradigm formalized by Wichs (ITCS ’13) and has implications for other cryptographic tasks.
- There is no universal implementation of the Fiat-Shamir transform whose security can be black-box reduced to a cryptographic game assumption. This extends the impossibility result of Bitansky et al. (TCC ’13) to the CRQS model.
- We impose severe limitations on constructions of quantum lightning (Zhandry, Eurocrypt ’19). If a scheme allows n lightning states’ serial numbers (of length m such that n > m) to be combined in such a way that the outcome has entropy, then it implies W1TRO, and thus cannot be black-box reduced to a cryptographic game assumption.
Senior Product Manager
Aspen Technology
Biography
Montreal-based quantum physicist, senior product manager, and full stack developer with strong experience building award-winning hardware and software products. Currently Senior Product Manager at Aspen Technology leading connectivity and AI inference at the Edge. Prior to Aspen Technology, I worked at Machine-To-Machine Intelligence (M2Mi) a leader in IoT Security and Management located at NASA Ames research center in the heart of Silicon Valley.
Prior to M2Mi, built SQR Technologies a belgian quantum based, hardware security startup that pioneered distributed quantum key generation. Acquired by IDQ (Switzerland). Awarded a Ph.D. in Physics (Quantum Cryptography) from the University of Brussels. Research interests include: quantum cloning, experimental quantum cryptography, quantum noise reduction, and quantum random number generation.
10h55 Mot d'ouverture (Salon A)
11h00 Présentation (Salon A)
12h00 Lunch (4 canards)
13h30 Présentation (Salon A)
14h15 Présentation (Salon A)
15h00 Pause café (Salon C)
15h30 Présentation (Salon A)
16h30 Session Écosystème quantique (Salon A)
17h00 Session d'affiches et rafaîchissements (Salon C)
19h30 Souper INTRIQ (4 canards)
9h00 Présentation (Salon A)
10h00 Présentation (Salon A)
10h30 Pause café (Salon C)
11h00 Présentation (Salon A)
11:h30 Présentation (Salon A)
12h00 Lunch (4 canards)
13h30 Présentation (Salon A)
14h30 Présentation (Salon A)
15h00 Pause café (Salon C)
15h30 Présentation (Salon A)
16h00 Présentation (Salon A)
16h30 Mot de clôture (Salon A)
Chercheuse, Laboratoire Albert Fert, CNRS, France
Quantum neuromorphic computing with superconducting circuits
Neuromorphic computing aims to implement neural-network–like information processing directly in hardware. Beyond conventional, isomorphic architectures that mimic the topology of neurons interconnected through synapses, non-isomorphic approaches harness more general physical systems and their intrinsic dynamics to perform computation. In this framework, input data are encoded in one of the control parameters of a physical system whose nonlinear response, governed by tunable parameters, enables complex transformations without explicitly reproducing neural network structures. Nonlinearity, which is essential for information processing, can arise from the intrinsic system dynamics, the encoding of input data, and, in quantum systems, from the measurement process through quantum back-action.
Key challenges in the field include identifying how to harness the natural evolution of a physical system for useful computation, understanding the physical origins of computational expressivity, and developing efficient training strategies adapted to quantum hardware. In this talk, I will present our recent experimental and numerical investigations of these questions using parametrically coupled bosonic modes implemented with superconducting circuits. I will discuss how encoding, control parameters, and measured observables shape the system dynamics [Dudas, npj Quant. Info., (2023); Carles, PRApplied (2026)], together with the training strategies we have explored, including model-based approaches such as backpropagation [Dudas, Sci. Rep., (2026)], and ongoing efforts towards physics-based approaches such as equilibrium propagation. These results highlight how quantum dynamics can be leveraged for neuromorphic computation.
Chercheur, Massachusetts Institute of Technology, USA
Harmonics in Josephson Junction Circuits
Josephson tunnel junctions are essential elements of superconducting quantum circuits. While it is typically assumed that these junctions possess a 2π-periodic sinusoidal potential, higher-order “harmonic” corrections can drastically modify the overall circuit properties.
In this talk, I will discuss two avenues of research in our group related to harmonics. In the first, we investigate the source of unanticipated harmonics in standard tunnel junctions. Two potential sources are the intrinsic Andreev processes intrinsic to the Josephson junction and the inductance of the metallic traces connecting the junction to other circuit elements. In our recent work [Kim et al., Nature Physics (2026)], we developed a method to distinguish between these two sources using superconducting quantum interference devices (SQUIDs). The observed scaling of the second harmonic with Josephson-junction size indicates that it is due almost entirely to the trace inductance in our devices. These results inform the design of next-generation superconducting circuits for quantum information processing and the investigation of the supercurrent diode effect.
The second avenue of research involves leveraging harmonics to realize a noise-resilient qubit. In our recent theoretical work [Hays et al., PRX Quantum (2025)], we engineered harmonic amplitudes to create a periodic potential with two non-degenerate minima. The qubit, which we dub “harmonium”, is formed from the lowest-energy states of each minimum. Bit-flip protection of the qubit arises due to the localization of each qubit state to their respective minima, while phase-flip protection can be understood by considering the circuit within the Born-Oppenheimer approximation. We will discuss the operating principles of this qubit and progress towards experimental realization.
Co-fondateur et directeur de la technologie à QphoX, Pays-Bas
Titre à venir
Les conférenciers et conférencières de l'écosystème seront annoné(e)s prochainement
Les conférenciers et conférencières INTRIQ seront annoné(e)s prochainement
Doctorante, Université McGill
Directeur: Kai Wang
Fisher Optimized Multiplane Light Conversion for Quantum Parameter Estimation
We propose a self-optimizing photonic neural network based on multiplane light conversion (MPLC) for quantum parameter estimation. Unlike static mode sorters, our system adaptively learns measurement strategies by maximizing Classical Fisher Information (CFI) using a simultaneous perturbation stochastic approximation algorithm. We demonstrate this on the two-point source separation problem. Our approach achieves near-optimal precision (reaching the Quantum Fisher Information limit) and maintains robustness against centroid misalignment, outperforming standard direct imaging and spatial mode demultiplexing methods.
Étudiant à la maîtrise, Université McGill
Directrice: Tami Pereg-Barnea
Titre à venir
Doctorant, Polytechnique Montréal
Directeur: Stéphane Kéna-Cohen
Titre à venir
Stagiaire, Université de Sherbrooke
Directeur: Stéfanos Kourtis
Titre à venir
Doctorant, École de technologie supérieure
Directeur: Jacob Biamonte
Title to be announced
Étudiant à la maîtrise, Université de Montréal
Directeur: Richard MacKenzie
Topological edge states in one dimensional insulators as exceptional points of the Hamiltonian
We provide a physically insightful derivation of Bulk-Boundary Correspondence for one dimensional semi-infinite chains. To do so, we analytically continue the Bloch Hamiltonian and interpret states with zeros in its sublattices as (not necessarily topological) edge states. In the analytically continued Bloch Hamiltonian, chiral symmetry leads to the existence of exceptional points corresponding to topological edge states. Through this insight, the quantization of the Berry phase can be attributed to the presence of exceptional points in the analytically continued Hamiltonian. Finally, we derive winding numbers that count the numbers of topological and non-topological edge states. This winding is, contrary to the Zak phase, independent of the choice of unit cell.
Étudiant à la maîtrise, NRC Ottawa
Directeur: Louis Gaudreau
Exploring Alternative Layered Materials as Gate Dielectrics for 2D Material Based Devices
The performance and scalability of two-dimensional (2D) based quantum devices are strongly influenced by the choice of gate dielectric. In gate-defined quantum devices high-κ dielectrics improve electrostatic tunability, and reduce gate leakage. Hexagonal boron nitride (hBN), a 2D layered material, has become a widely used dielectric due to the clean interface it forms with 2D materials and its wide band gap. However, its relatively low dielectric constant (κ ≈ 2.5–4) [1] limits the gate capacitance, and incidentally the charge carrier density.
This project aims to explore Lanthanum OxyBromide (LaOBr) as an alternative crystalline layered dielectric. Its properties such as a high dielectric constant, large band gap, and its compatibility with van der Waals heterostructures [2] makes it a promising material to overcome the limitations of hBN while preserving the benefits of a 2D-2D interface.
To evaluate LaOBr as a suitable gate dielectric, we fabricated 2D-based field-effect devices and characterized key electrical properties, focusing on the gate leakage current, device carrier mobility, gate dielectric breakdown, and dielectric constant. This work will prompt the study of other layered high k dielectrics as alternatives to hBN, providing additional tuning knobs for heterostructure fabrication.
[1] J. Boddison-Chouinard, et al. npj 2D Mater Appl 7, 50 (2023)
[2] A. Soll et al ACS Nano 2024, 18, 15, 10397–10406 (2024)
Stagiaire, Université de Montréal
Directeur: Richard MacKenzie
A study of new types of states in generalized SSH systems
The Su–Schrieffer–Heeger (SSH) model is a fundamental example of topology in one-dimensional lattices. When extended to include longer-range hopping (SSH-N models), the structure of eigenstates becomes significantly more complex and remains only partially understood.
We analyze these generalized models using Bloch theory and numerical methods to determine their band structures and eigenmodes. We show that both the number and nature of eigenstates depend strongly on the unit cell geometry and coupling parameters.
Unlike the standard SSH model, extended hopping leads to new classes of solutions, including additional bulk states and exponentially localized modes. These results provide a framework for engineering novel quantum states in one-dimensional systems.
Étudiante à la maîtrise, Université de Sherbrooke
Directeur: Stéfanos Kourtis
Titre à venir
Doctorant, Université McGill
Directeur: Jack Sankey
High Mode Matching Fiber Fabry Perot Cavity
We optimize the fiber/optical cavity interfaces to improve the coupling between the cavity mode and the fiber mode. This aims to address a significant source of loss in quantum communications and to enhance measurements using Fabry-Perot cavities coupled to optical fibers.
Our method involves measuring the glass-air reflection inside the fiber during its preparation, before the deposition of the mirror. This information, combined with surface profilometry, allows us to predict the coupling.
Based on our results with single-mode fiber, we predict a coupling efficiency exceeding 95% on the flat side of a plano-convex cavity. As a result, this coupling will no longer be a limiting factor in the quantum efficiency of these systems.
Doctorant, Université de Montréal
Directeur: Richard MacKenzie
Étude de la chaîne de Su-Schrieffer-Heeger (SSH) avec un soliton parfaitement localisé
On étudie l’impact sur les états et énergies propres du modèle SSH de l’ajout d’un soliton parfaitement localisé à la frontière entre deux configurations topologiques. On observe l’apparition d’états d’interfaces de hautes (k imaginaire) et de basses (k complexe) énergies dans le cas infini. Pour le cas fini, on observe que les états de bord du modèle SSH usuel peuvent s’hybrider avec ces nouveaux états. On trouve aussi les points critiques entre les différentes configuration du système. On finit par une étude numérique de l’ajout de bruit au système.
Doctorant, Polytechnique Montréal
Directeur: Stéphane Kéna-Cohen
Intensity squeezed single photon sources at room temperature from organic molecules
Stagiaire, École de technologie supérieure
Directeur: Jacob Biamonte
Titre à venir
Doctorant, Université de Sherbrooke
Directeur: Mathieu Juan
Disordered superconductor resonators under magnetic fields
10:55 Opening remarks (Salon A)
11:00 Talk (Salon A)
12:00 Lunch (4 canards)
13:30 Talk (Salon A)
14:00 Talk (Salon A)
14:30 Talk (Salon A)
15:00 Coffee break (Salon C)
15:30 Talk (Salon A)
16:30 Quantum Ecosystem session (Salon A)
17:00 Poster session with refreshments (Salon C)
19:30 INTRIQ dinner (4 canards)
9:00 Talk (Salon A)
10:00 Talk (Salon A)
10:30 Coffee break (Salon C)
11:00 Talk (Salon A)
11:30 Talk (Salon A)
12:00 Lunch (4 canards)
13:30 Talk (Salon A)
14:30 Coffee break (Salon C)
15:00 Talk (Salon A)
16:00 Talk (Salon A)
16:30 Closing remarks (Salon A)
Researcher, Laboratoire Albert Fert, CNRS, France
Quantum neuromorphic computing with superconducting circuits
Neuromorphic computing aims to implement neural-network–like information processing directly in hardware. Beyond conventional, isomorphic architectures that mimic the topology of neurons interconnected through synapses, non-isomorphic approaches harness more general physical systems and their intrinsic dynamics to perform computation. In this framework, input data are encoded in one of the control parameters of a physical system whose nonlinear response, governed by tunable parameters, enables complex transformations without explicitly reproducing neural network structures. Nonlinearity, which is essential for information processing, can arise from the intrinsic system dynamics, the encoding of input data, and, in quantum systems, from the measurement process through quantum back-action.
Key challenges in the field include identifying how to harness the natural evolution of a physical system for useful computation, understanding the physical origins of computational expressivity, and developing efficient training strategies adapted to quantum hardware. In this talk, I will present our recent experimental and numerical investigations of these questions using parametrically coupled bosonic modes implemented with superconducting circuits. I will discuss how encoding, control parameters, and measured observables shape the system dynamics [Dudas, npj Quant. Info., (2023); Carles, PRApplied (2026)], together with the training strategies we have explored, including model-based approaches such as backpropagation [Dudas, Sci. Rep., (2026)], and ongoing efforts towards physics-based approaches such as equilibrium propagation. These results highlight how quantum dynamics can be leveraged for neuromorphic computation.
Researcher, Massachusetts Institute of Technology, USA
Harmonics in Josephson Junction Circuits
Josephson tunnel junctions are essential elements of superconducting quantum circuits. While it is typically assumed that these junctions possess a 2π-periodic sinusoidal potential, higher-order “harmonic” corrections can drastically modify the overall circuit properties.
In this talk, I will discuss two avenues of research in our group related to harmonics. In the first, we investigate the source of unanticipated harmonics in standard tunnel junctions. Two potential sources are the intrinsic Andreev processes intrinsic to the Josephson junction and the inductance of the metallic traces connecting the junction to other circuit elements. In our recent work [Kim et al., Nature Physics (2026)], we developed a method to distinguish between these two sources using superconducting quantum interference devices (SQUIDs). The observed scaling of the second harmonic with Josephson-junction size indicates that it is due almost entirely to the trace inductance in our devices. These results inform the design of next-generation superconducting circuits for quantum information processing and the investigation of the supercurrent diode effect.
The second avenue of research involves leveraging harmonics to realize a noise-resilient qubit. In our recent theoretical work [Hays et al., PRX Quantum (2025)], we engineered harmonic amplitudes to create a periodic potential with two non-degenerate minima. The qubit, which we dub “harmonium”, is formed from the lowest-energy states of each minimum. Bit-flip protection of the qubit arises due to the localization of each qubit state to their respective minima, while phase-flip protection can be understood by considering the circuit within the Born-Oppenheimer approximation. We will discuss the operating principles of this qubit and progress towards experimental realization.
Co-Founder and CTO at QphoX, Netherland
Title to be announced
Speakers to be announced
Speakers to be announced
PhD student, McGill University
Director: Kai Wang
Fisher Optimized Multiplane Light Conversion for Quantum Parameter Estimation
We propose a self-optimizing photonic neural network based on multiplane light conversion (MPLC) for quantum parameter estimation. Unlike static mode sorters, our system adaptively learns measurement strategies by maximizing Classical Fisher Information (CFI) using a simultaneous perturbation stochastic approximation algorithm. We demonstrate this on the two-point source separation problem. Our approach achieves near-optimal precision (reaching the Quantum Fisher Information limit) and maintains robustness against centroid misalignment, outperforming standard direct imaging and spatial mode demultiplexing methods.
Master student, McGill University
Director: Tami Pereg-Barnea
Title to be announced
PhD student, Polytechnique Montréal
Director: Stéphane Kéna-Cohen
Title to be announced
Intern, Université de Sherbrooke
Director: Stéfanos Kourtis
Title to be announced
PhD student, École de technologie supérieure
Director: Jacob Biamonte
Title to be announced
Master student, Université de Montréal
Director: Richard MacKenzie
Topological edge states in one dimensional insulators as exceptional points of the Hamiltonian
We provide a physically insightful derivation of Bulk-Boundary Correspondence for one dimensional semi-infinite chains. To do so, we analytically continue the Bloch Hamiltonian and interpret states with zeros in its sublattices as (not necessarily topological) edge states. In the analytically continued Bloch Hamiltonian, chiral symmetry leads to the existence of exceptional points corresponding to topological edge states. Through this insight, the quantization of the Berry phase can be attributed to the presence of exceptional points in the analytically continued Hamiltonian. Finally, we derive winding numbers that count the numbers of topological and non-topological edge states. This winding is, contrary to the Zak phase, independent of the choice of unit cell.
Master student, NRC Ottawa
Director: Louis Gaudreau
Exploring Alternative Layered Materials as Gate Dielectrics for 2D Material Based Devices
The performance and scalability of two-dimensional (2D) based quantum devices are strongly influenced by the choice of gate dielectric. In gate-defined quantum devices high-κ dielectrics improve electrostatic tunability, and reduce gate leakage. Hexagonal boron nitride (hBN), a 2D layered material, has become a widely used dielectric due to the clean interface it forms with 2D materials and its wide band gap. However, its relatively low dielectric constant (κ ≈ 2.5–4) [1] limits the gate capacitance, and incidentally the charge carrier density.
This project aims to explore Lanthanum OxyBromide (LaOBr) as an alternative crystalline layered dielectric. Its properties such as a high dielectric constant, large band gap, and its compatibility with van der Waals heterostructures [2] makes it a promising material to overcome the limitations of hBN while preserving the benefits of a 2D-2D interface.
To evaluate LaOBr as a suitable gate dielectric, we fabricated 2D-based field-effect devices and characterized key electrical properties, focusing on the gate leakage current, device carrier mobility, gate dielectric breakdown, and dielectric constant. This work will prompt the study of other layered high k dielectrics as alternatives to hBN, providing additional tuning knobs for heterostructure fabrication.
[1] J. Boddison-Chouinard, et al. npj 2D Mater Appl 7, 50 (2023)
[2] A. Soll et al ACS Nano 2024, 18, 15, 10397–10406 (2024)
PhD student, Université de Montréal
Director: Philippe St-Jean
Anomalous Quantum Hall Effect for Light
We report an anomalous Hall effect for light confined in a silicon-based photonic crystal. A pseudo-magnetic field is induced through a spatial deformation of a honeycomb lattice. We further observe a polarization-dependent transverse drift through the implementation of an artificial electric field.
Intern, Université de Montréal
Director: Richard MacKenzie
A study of new types of states in generalized SSH systems
The Su–Schrieffer–Heeger (SSH) model is a fundamental example of topology in one-dimensional lattices. When extended to include longer-range hopping (SSH-N models), the structure of eigenstates becomes significantly more complex and remains only partially understood.
We analyze these generalized models using Bloch theory and numerical methods to determine their band structures and eigenmodes. We show that both the number and nature of eigenstates depend strongly on the unit cell geometry and coupling parameters.
Unlike the standard SSH model, extended hopping leads to new classes of solutions, including additional bulk states and exponentially localized modes. These results provide a framework for engineering novel quantum states in one-dimensional systems.
Master student, Université de Sherbrooke
Directeur: Stéfanos Kourtis
Title to be announced
PhD student, McGill University
Director: Jack Sankey
High Mode Matching Fiber Fabry Perot Cavity
We optimize the fiber/optical cavity interfaces to improve the coupling between the cavity mode and the fiber mode. This aims to address a significant source of loss in quantum communications and to enhance measurements using Fabry-Perot cavities coupled to optical fibers.
Our method involves measuring the glass-air reflection inside the fiber during its preparation, before the deposition of the mirror. This information, combined with surface profilometry, allows us to predict the coupling.
Based on our results with single-mode fiber, we predict a coupling efficiency exceeding 95% on the flat side of a plano-convex cavity. As a result, this coupling will no longer be a limiting factor in the quantum efficiency of these systems.
PhD student, Université de Montréal
Director: Richard MacKenzie
Étude de la chaîne de Su-Schrieffer-Heeger (SSH) avec un soliton parfaitement localisé
On étudie l’impact sur les états et énergies propres du modèle SSH de l’ajout d’un soliton parfaitement localisé à la frontière entre deux configurations topologiques. On observe l’apparition d’états d’interfaces de hautes (k imaginaire) et de basses (k complexe) énergies dans le cas infini. Pour le cas fini, on observe que les états de bord du modèle SSH usuel peuvent s’hybrider avec ces nouveaux états. On trouve aussi les points critiques entre les différentes configuration du système. On finit par une étude numérique de l’ajout de bruit au système.
PhD student, Polytechnique Montréal
Director: Stéphane Kéna-Cohen
Intensity squeezed single photon sources at room temperature from organic molecules
Intern, École de technologie supérieure
Director: Jacob Biamonte
Title to be announced
PhD student, Université de Sherbrooke
Director: Mathieu Juan
Disordered superconductor resonators under magnetic fields