October 11, 2022 11:00 AM

October 12, 2022 4:30 PM
October 11, 2022 11:00 AM

October 12, 2022 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
LouisPhilippe 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 PeregBarnea, McGill University
Dynamic topology  quantized conductance and Majoranas on wires
Professor Philippe StJean, Université de Montréal
Topological physics with light and matter: new horizons
Break
Louis Gaudreau, National Research Council Canada (Ottawa)
Entanglement distribution via coherent photontospin conversion in semiconductor quantum dot circuits
Philippe Lamontagne, National Research Council Canada (Montréal)
BlackBox Impossibility in the Common Reference Quantum State Model
Olivier GagnonGordillo, Québec quantique lead
Presentation of the Québec Quantum ecosystem
Institut quantique  Université de Sherbrooke
Classical and quantum computations as tensor networks
Tensor networks are multilinearalgebra data structures that are finding application in diverse fields of science, from quantum manybody 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 nonlinear 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 sideband cooling. In general, linear cavities are favoured to allow for large photon number providing stronger cooling. I will show that, surprisingly, nonlinear 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 outofequilibrium 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 timeperiodic 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 faulttolerant quantum computation[i]. In the late 2000s, Duncan Haldane (colaureate 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 solidstate, leading to the emergence of a blooming field called topological photonics[iii].
In this presentation, I will describe recent experimental works based on excitonpolaritons, a hybrid lightmatter 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 welldefined topological properties in lattices of coupled microcavities and makes them inherently nonhermitian; on the other hand, their matter part gives rise to a strong Kerrlike 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 solidstate. I will conclude this presentation by discussing how topological protection can provide a powerful asset for generating and stabilizing manybody 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 manybody 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. StJean et al. Opt. Mat. Express 11, 1119 (2021)
[v] I. Carusotto and C. Ciuti. Rev. Mod. Phys. 85, 299 (2013)
[vi] P. StJean 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 photontospin 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 timebin encoded photonic qubits to electron spin qubits and will describe adaptations to employ heavy holes which have a number of attractive properties including gfactor 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 cosupervision 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 exchangeonly 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 lightmatter 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 nanooptoelectronics group with Frank Koppens where he was awarded the prestigious MarieCurie 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)
BlackBox 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 wellknown Common Reference String (CRS) model but appears to be more powerful. In the twoparty setting, a CRQS can sometimes exhibit properties associated with a Random Oracle queried once. We formalize this notion as a Weak OneTime 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 blackbox 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 FiatShamir transform whose security can be blackbox 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 blackbox reduced to a cryptographic game assumption.
Senior Product Manager
Aspen Technology
Biography
Montrealbased quantum physicist, senior product manager, and full stack developer with strong experience building awardwinning 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 MachineToMachine 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.
10:55 Mot d'ouverture(Salon A)
11:00 Bill Coish, McGill University (Salon A)
Decoherence and open quantum systems
12:00 Diner (Salle Knowlton)
13:30 Ebrahim Karimi, Ottawa Universiy (Salon A)
Structured Photons – Their Application inQuantum Photonics
14:30 Pause café (Salon C)
15:00 Martin Houde, Polytechnique Montréal (Salon A)
Waveguided sources of consistent, singletemporalmode squeezed light:
the good, the bad, and the ugly
15:25 Sho Onoe, Polytechnique Montréal (Salon A)
Simultaneous detection of field quadratures in the timedomain via
electrooptic sampling
15:50 Denis Seletskiy, Polytechnique Montréal (Salon A)
CanadaEU consortium on Midinfrared quantum sensing
16h15 Mme Fran Delhoume (Salon A)
Activité EDI : les microagressions sur le lieu de travail
17:15 Session d'affiches avec rafraichissements (Salon C)
19:30 Souper INTRIQ (Salle Knowlton)
8:30 Chinmay Nirkhe, IBM quantum, Cambridge(Salon A)
NLTS Hamiltonians from good quantum codes
9:30 Jonathan Durandau, Université de Sherbrooke (Salon A)
Quantum Circuit Compilation and Quantum Computer Architecture
9:50 Pause café (Salon C)
10:20 Monika Aidelsburger, Munich University (Salon A)
Quantum simulation of Floquet topological phases with ultracold atoms
11:20 Tami PeregBarnea, McGill University (Salon A)
Majorana fermions, where to find them and how to use them
12:00 Diner (Sale Knowlton)
13:30 Roger Melko, Perimeter Institute (Salon A)
Quantum Simulation and Rydberg Atom Arrays
14:30 Pause café (Salon C)
15:00 Karthik Chinni, Polytechnique Montréal (Salon A)
Trotter errors from dynamical structural instabilities of floquet maps
in quantum simulation
15:30 Michael Hilke, McGill University (Salon A)
Molecular single photon sources for quantum communication
and enhanced sensing
16:10 Mot de fermeture
Quantum Optics Group
Munich University
Quantum simulation of Floquet topological phases with ultracold atoms
Wellcontrolled synthetic quantum systems, such as ultracold atoms in optical lattices, offer intriguing possibilities to study complex manybody problems in regimes that are beyond reach using stateoftheart classical computations. The basic idea is to construct and use a wellcontrolled quantum manybody system in order to study its in and outofequilibrium properties and potentially use it to develop more efficient tailored numerical methods that can then be applied to other systems that are not directly accessible with the simulator.
An important future quest concerns the development of novel experimental techniques that allow us to expand the range of models that can be accessed. I will demonstrate this using the example of topological lattice models, which in general do not naturally appear in coldatom experiments. I will show how the technique of periodic driving, also known as Floquet engineering, facilitates their realization and show how chargeneutral atoms in lattices can mimic the behavior of charged particles in the presence of an external magnetic field. A key ingredient for quantum simulation is the degree of control one has over the individual particles and the microscopic parameters of the model. We have recently succeeded to not only use the technique of periodic driving to emulate physical systems that we know exist in nature, but to take this idea one step further and realize completely new topological regimes that do not have any static analog.
Department of Physics
University of Ottawa
Structured Photons – Their Application in Quantum Photonics
Photons, the quanta of light, possess several different degrees of freedom, e.g., frequency, polarisation, spatial and temporal modes, which can be used as platforms for quantum information applications. Polarisation, corresponding to the vectorial nature of light, is bidimensional, and thus can represent ‘0’ and ‘1’ in the digital world. Unlike polarisation, transverse and temporal modes would provide an unbonded vector space and could be used to extend the alphabet beyond the ‘0’s and ‘1’s to any arbitrary integer numbers. Photons in superposition states of these different degrees of freedom are known as Structured Photons. In the classical regime, structured light has found tremendous applications, e.g., overcoming the diffraction limit (STED microscopy), for optical spanners, communication multiplexing, and generating nontrivial 3D topologies such as Möbius, ribbons and knots. In the quantum domain, structured photons may be used to realise higherdimensional states, and thus are employed in quantum communication, computation, and simulation applications.
The recent progress, challenges, and applications of structured photons in modern photonics, as well as their applications in highdimensional quantum communication, e.g., freespace, underwater, fibre and curved spacetime, links and their security analysis, will be the subject of my talk.
Activité EDI : les microagressions sur le lieu de travail
Diplômée d'une maîtrise en développement organisationnel à HEC Montréal et d’unprogramme court en gestion de l'équitédiversitéinclusion (EDI) au travail de l’UQAR, Fran est formatrice en neuroinclusion en plus de collaborer comme analyste EDI avec la firmeconseil URelles et d'œuvrer comme chargée de cours à l’Université de Sherbrooke. Son mémoire, reçu avec mention, remet en question les fondements sousjacents des pratiques d'inclusion professionnelle des personnes neurodivergentes. Elle est aussi coanimatrice du balado Les Neurodivertissantes qui a pour mission de vulgariser, démocratiser et partager les expertises et savoirs autour de la neurodiversité au travail.
Malgréles efforts déployés en faveur de l'équité, de la diversité et de l'inclusion (EDI), les membres des groupes historiquement marginalisés continuent de faire l'objet de préjugés, d'inéquités, de microagressions et d'expériences discriminatoires dans le milieu de travail. Ces expériences, qui se déroulent au quotidien, sont liées à une baisse de la satisfaction au travail, à l'épuisement professionnel et la dépression, au désengagement professionnel, à un taux de rotation plus élevé et à d'autres problèmes sociaux et de santé. Des lieux de travail plus inclusifs sont au contraire associés à une plus grande satisfaction et rétention, à un meilleur engagement, à un sentiment d'appartenance plus élevé et à une innovation accrue. Dans cette présentation, nous donnons un aperçu compréhensif de ce que sont les microagressions et de leurs impacts. Nous examinons également le rôle et la responsabilité de l'écosystème et de ses membres face aux microagressions, ainsi que les stratégies qui peuvent être déployées aux niveaux individuel et organisationnel.
Perimeter Institute
Quantum Simulation and Rydberg Atom Arrays
One major goal of the current generation of quantum devices is to “simulate” (or emulate) the Hamiltonians found in condensed matter and material systems. Such quantum simulation strategies are particularly important in cases where it is challenging to simulate these systems with traditional computational tools, such as quantum Monte Carlo or tensor network methods  numerical schemes that have been under development for decades. Recently, the rapidlyadvancing field of machine learning has introduced a host of new methods suitable for this task, involving neural network architectures and datadriven learning strategies.
In this talk, I will discuss the complementary role of experimental and in silico quantum simulations through the lens of machine learning, using the example of presentday Rydberg atom quantum computers. In particular, I will illustrate the utility of machine learning methods to leverage data from real experiments, and speculate on the future of scientific discovery in quantum manybody simulators that hybridize traditional and datadriven approaches.
IBM quantum, Cambridge
NLTS Hamiltonians from good quantum codes
The quantum PCP conjecture is one of the central open questions in quantum complexity theory. It asserts that calculating even a rough approximation to the ground energy of a local Hamiltonian is intractable even for quantum devices. The widely believed separation between the complexity classes NP and QMA necessitates that polynomial length classical proofs do not exist for calculating the ground energy. This further implies that lowenergy states of local Hamiltonians cannot be described by constant depth quantum circuits.
The "Nolowenergy trivial states (NLTS)" conjecture by Freedman and Hastings posited the existence of such Hamiltonians. This talk will describe a line of research culminating in a proof of the NLTS conjecture by Anshu, Breuckmann, and Nirkhe. The construction is based on quantum error correction and in the talk, I will elaborate on how error correction, local Hamiltonians, and lowdepth quantum circuits are related.
Postdoc, Polytechnique Montréal
Directeur: Nicolas Quesada
Trotter errors from dynamical structural instabilities of floquet maps in quantum simulation
We study the behavior of errors in the quantum simulation of spin systems with longrange multibody interactions resulting from the TrotterSuzuki decomposition of the timeevolution operator. We identify a regime where the Floquet operator underlying the Trotter decomposition undergoes sharp changes even for small variations in the simulation step size. This results in a time evolution operator that is very different from the dynamics generated by the targeted Hamiltonian, which leads to a proliferation of errors in the quantum simulation. These regions of sharp change in the Floquet operator, referred to as structural instability regions, appear typically at intermediate Trotter step sizes and in the weakly interacting regime, and are thus complementary to recently revealed quantum chaotic regimes of the Trotterized evolution. We characterize these structural instability regimes in pspin models, transversefield Ising models with alltoall pbody interactions, and analytically predict their occurrence based on unitary perturbation theory. We further show that the effective Hamiltonian associated with the Trotter decomposition of the unitary timeevolution operator, when the Trotter step size is chosen to be in the structural instability region, is very different from the target Hamiltonian, which explains the large errors that can occur in the simulation in the regions of instability. These results have implications for the reliability of nearterm gatebased quantum simulators, and reveal an important interplay between errors and the physical properties of the system being simulated.
Professeur, McGill University
Decoherence and open quantum systems
In this talk, I will give a brief introduction to the physics of decoherence and quantum dynamics, along with methods for noise mitigation (e.g., dynamical decoupling). The emphasis will be on applications in spectroscopy, qubit readout, and quantum computing.
Doctorant, Université de Sherbrooke
Directeur: Yves BérubéLauzière
Quantum Circuit Compilation and Quantum Computer Architecture
As the technology of qubit and the number of quantum algorithms grow, the next great objective of quantum engineering is an extensible quantum computer. Yet, multiple problems arise, the first one being the qubit connectivity problem. This problem is caused by different characteristics of the quantum qubit, such as the noncloning theorem.
In this presentation, we will present and characterize the connectivity problem on two different types of qubits, superconducting and shuttled trapped ions, using two existing machine as an example, the IBM computer and the SchmidtKaler group computer. We will analyze the connectivity of these machines and propose some solutions that we found in our research.
Professeur, McGill University
Molecular single photon sources for quantum communication and enhanced sensing
The pioneering experiments by Hanbury and Twiss are considered by many as the beginnings of quantum optics. These experiments are now particularly relevant in the context of quantum photonics and the characterization of single photon sources. After introducing these experiments and concepts, I will discuss molecular single photon sources, which are rapidly emerging as highly competitive contenders for quantum photonics. They combine the tunability and malleability typically associated with semiconductor based systems, such as quantum dots, and the high purity typically found in atomic systems. Here I will focus on a particular molecule/nanocrystal (BDT/antracene) hybrid system that exhibits a very high, on demand, single photon emission purity, even at room temperature. This system can easily be processed and integrated into various photonic and sensing applications. Two main applications will be discussed in more detail: (1)ambient quantum key distribution [1] with concrete advantages over conventional attenuated laser pulses and (2) local (10100mnm) contact less temperature sensing at cryogenic temperatures. This is particularly interesting when all other techniques fail. This work was done in collaboration with the Toninelli group at LENS and theUniversity of Florence.
[1] G.Murtaza, et al. arXiv:2202.12635 (2022)
Postdoc, Polytechnique Montréal
Directeur: Nicolas Quesada
Waveguided sources of consistent, singletemporalmode squeezed light: the good, the bad, and the ugly
We study the oretically how the temporal mode structure of squeezed states generated by a parametric waveguided source is modified when driven by pumps of different brightness but identical profiles. We find that the temporal modes of these squeezed states are partially mismatched and thus distinguishable, which is undesirable when using these states as resources for quantum computing or heralded state generation. By studying common frequency filtering techniques used experimentally, we find that although one can regain indistinguishability it comes at the price of potentially greatly reducing the purity of the state. We consider three different source configurations: unapodized single pass, apodized single pass, and apodized double pass. We find that the double pass configuration produces better results with more indistinguishable states.
Postdoc, Polytechnique Montréal
Directeur: Denis Seletskiy
Simultaneous detection of field quadratures in the timedomain via electrooptic sampling
Analysis of quantum optical states is typically performed using techniques of homodyne detection, where the superposition of the quantum state under study and a classical reference at the same frequency is registered in a squarelaw detector. Due to the lack of quantumlimited sources and efficient detectors, progress with the homodyne characterization of quantum states in the midinfrared (midIR) has been stagnant. Recently, a technique of electrooptic sampling has established itself as the frontier of ultrafast photonics in the midinfrared range, and recent experiments demonstrated the detection of midIR quantum fields, including bare vacuum, directly in the time domain. The temporal resolution comes from the duration of the gating function, commonly reaching 6 fs (1 fs = 10^15 seconds). Here we consider a possibility to efficiently use the entire bandwidth of the gating function to accomplish simultaneous detection of both field quadratures. Motivated by the understanding of the mode structure of the amplitude and Hilbert transform quadratures, we propose multiplexing and modematching operations on the gating function to extract full quantum information on both quantities, simultaneously. The proposed experiment is poised to open a novel path toward quantum state tomography directly in the time domain, promising novel applications toward timedomain quantum spectroscopy and novel explorations in relativistic quantum information.
Professeure. McGill University
Majorana fermions, where to find them and how to use them
Majorana fermions have been proposed as potential building blocks of qubits already in 1997. However, despite many efforts to realize them in experiments, they have not been identified without doubt yet. In this tutorial we will go over some simple models of topological superconductivity which give rise to Majorana fermions. We will also discuss proposals for realizing Majoranahosting systems and Majoranabased qubits and discuss some recent experiments.
Professeur, Polytechnique Montréal
Sujet à venir
Doctorant, Université de Sherbrooke
Directeur: Stéfanos Kourtis
Discrete optimization inthe MPSMPO language
In discrete optimization problems, one usually asks for an optimal object from a finite set. Suchproblems appear in many fields ranging from logistics to quantum error correction. Many of these are NPcomplete, making exact solutions too hard to find and thus leaving a battle field for different approximate algorithms. In the current study, we show how to marry such probblems with tensor networks and show several relevant example. The code for the study is available as a python package.
Doctorant, Université de Sherbrooke
Directeur: Michel PioroLadrière
Sujet à venir
Étudiant à la maîtrise, Université d'Ottawa
Directrice: Anne Broadbent
Coset State Uncloneability to ReceiverIndependent QKD
We construct a receiverindependent quantum key distribution (QKD)scheme, which strengthens the notion of onesided device independent QKD of Tomamichel, Fehr, Kaniewski, and Wehner [NJP 2013] by also permitting the receiver's classical device to be untrusted. Explicitly, the sender remains fully trusted while only the receiver's communication is trusted. We provide a construction that achieves the same asymptotic error tolerance as the scheme of Tomamichelet al.
To show security, we prove an extension of the MoE property of coset states introduced byColadangelo, Liu, Liu, and Zhandry [Crypto 2021]. In our stronger version, the player Charlie also receives Bob's answer prior to making his guess, thus simulating a party who eavesdrops on an interaction. To make use of this property, we express it as a new type of entropic uncertainty relation which arises naturally from the structure of the underlying MoE game.
Doctorant, Polytechnique Montréal
Directeur: Oussama Moutanabbir
Sujet à venir
Doctorant, Université de Sherbrooke
Directeur: Bertrand Reulet
Fluctuation Loops in Microwave circuits
Study of the outofequilibrium properties of a circuit using thermal noise as a probe.
Étudiant à la maîtrise, Université de Sherbrooke
Directeur: Bertrand Reulet
Sujet à venir
Doctorante, Université de Sherbrooke
Directeur: Bertrand Reulet
Detection of Higgs mode in a superconducting wire via impedance measurements in the microwave domain
Microwave investigation of Higgs Mode in a superconducting wire. Higgs mode in superconductors is an analogous of the Higgs boson in high energy physics that has been predicted by Anderson in the late 50s [1]. Its detection is usually difficult because of its weak coupling with electromagnetic fields. However, a recent theory predicted a huge increase of this coupling in the presence of a DC current, which translates into an anomaly in the complex conductivity at frequencies of the order of 2Δ [2]. Observation of Higgs modes in superconductors have been performed in the THz range [3]. A study in the microwave range could enable new measurement such as nonlocal conductivity to probe its propagation. We studied Titanium samples for which 2Δ is of the order of 1030 GHz and can be tuned with the sample thickness. In this experiment we present a precise and quantitative measurement of the high frequency complex impedance of a superconducting wire in the microwave range. In the absence of DC current, we compare our results with BCS theory at equilibrium. With current we observe a feature at frequency2Δ which behaves as predicted in [2] with a width much larger than expected. This experimentis the first step toward the integration of Higgs mode in electronic circuit.
[1] Anderson PW. 1958. Phys. Rev. 112:1900–16
[2] A. Moor and al., Amplitude Higgs Mode and Admittance in Superconductors with a Moving Condensate, PRL 118, 047001 (2017)).
[3] Matsunaga R, Hamada YI, Makise K, Uzawa Y, Terai H, et al. 2013. Phys. Rev. Lett. 111:057002
Doctorant, Polytechnique Montréal
Directeur: Nicolas Quesada
Validating the USTC Gaussian boson sampling experiment against classical mixtures of coherent states hypothesis
Recently, Zhong et al. have performed Gaussian boson sampling experiments using photonic circuits with up to 144 modes and threshold detectors. The samples produced in these experiments have been validated against several classical simulation strategies, such as sampling from probability distributions corresponding to thermal states or distinguishable photons. In this work we propose an alternative validation hypothesis that uses the probability distribution of mixtures of coherent states sent into a lossy interferometer. These mixtures result in classical Gaussian states with vacuum fluctuations in one quadrature and larger fluctuations in the other. To test this hypothesis, we compute the cumulants of the proposed distribution up to fourth order and compare them with the results obtained from the experimental samples and the ground truth distribution of the experiment (namely, the probability distribution of twomode squeezed states sent into a lossy interferometer). We also calculate crossentropy differences between the alternative and ground truth distributions, as well as between samples from the alternative distribution and experimental samples. We find that for the experiments with larger photon density, which are in the quantum advantage regime, the cumulants do not tell the ground state and alternative distributions apart. Additionally, the crossentropy differences indicate that the alternative hypothesis is a better description of the experimental data than the ground truth hypothesis. These results suggest that the results of the experiment can be efficiently reproduced with classical sampling algorithms.
Doctorante, McGill University
Directeur: Bill Coish
NonMarkovian transient spectroscopy in cavity QED
We theoretically analyze measurements of the transient field leaving a cavity as a tool for studying nonMarkovian dynamics in cavity quantum electrodynamics (QED). Combined with a dynamical decoupling pulse sequence, transient spectroscopy can be used to recover spectral features that may be obscured in the stationary cavity transmission spectrum due to inhomogeneous broadening. The formalism introduced here can be leveraged to perform in situ noise spectroscopy, revealing a robust signature of quantum noise arising from noncommuting observables,a purely quantum effect.
Stagiaire, McGill University
Directeur: Michael Hilke
Sujet à venir
Étudiante à la maîtrise, Université de Sherbrooke
Directeur: Mathieu Juan
Sujet à venir
Étudiante à la maîtrise, Université de Shebrooke
Directeur: Dave Touchette
Improving Qubit Routing with EPR Pairs
Doctorant, Université de Sherbrooke
Directrice: Eva DupontFerrier
Sujet à venir
Doctorant, Université de Sherbrooke
Director: Michel PioroLadrière
Realtime quantum dot stability diagram measurement using onthefly generated waveforms
Stability diagrams are essential to understand the energy landscape of the quantum dots and tune them into the spinqubit regime, but the voltage space to cover increases significantly with the number of quantum dots. While many advanced measurement techniques were proposed in the last few years to minimize the number of measurements needed to extract valuable information, another approach is to speed up the measurements themselves. Therefore, Keysight’s Quantum Engineering Toolkit (QET) was used to program the experimental routines inside the onboard fieldprogrammable gate arrays (FPGAs). While the programming of those routines takes time and specific knowledge, they run with minimal communications with the host computer which allows high processing speeds. With this approach, we achieve stability diagram measurements in around 30 ms and virtual gates calculations in under 100 ns. The flexibility of the FPGA programming also allows the routines to be adapted to more complex measurements that may include accelerated machine learning or statistical models. Those tools are a first step towards the scalable control of spin qubits using cryogenic electronics.
Doctorant, McGill University
Directeur: Kartiek Agarwal
Sujet à venir
Professonel & Doctorante, Université de Sherbrooke
Directeur: Michel PioroLadrière
Stagiaire, McGill University
Directrice: Lilian Childress
Improving the Sensitivity of NV Magnetometry
Doctorant, Université de Sherbrooke
Directeur: Stéfanos Kourtis
Sujet à venir
Doctorant, McGill University
Director: Lilian Childress
Coupling Colour Centers in Diamond to Fiber Microcavities
Color centers in diamond are promising solidstate spinqubit systems for quantum information thanks to their atomlike spinoptical properties. Two prospective candidates are the nitrogenvacancy (NV) and germaniumvacancy (GeV). Current implementations with the NV center are restricted by its low emission rate (3%) into its coherent transition and spectral diffusion. In turn, the use of the GeV is limited by its spinorbit interaction necessitating lowtemperature operation. We present our current results in coupling a fiberbased open microcavity (measured finesse of F~8000) to a GeV at ~ 15K. Achieving a reduced lifetime of 1.7+/0.1 ns (bare 6 ns) and an estimated Purcell Enhancement of the zerophonon line of ~24.
10:55 Opening remarks (Salon A)
11:00 Bill Coish, McGill University (Salon A)
Decoherence and open quantum systems
12:00 Lunch (Knowlton room)
13:30 Ebrahim Karimi, Ottawa Universiy (Salon A)
Structured Photons – Their Application inQuantum Photonics
14:30 Coffee break (Salon C)
15:00 Martin Houde, Polytechnique Montréal (Salon A)
Waveguided sources of consistent, singletemporalmode squeezed light:
the good, the bad, and the ugly
15:25 Sho Onoe, Polytechnique Montréal (Salon A)
Simultaneous detection of field quadratures in the timedomain via
electrooptic sampling
15:50 Denis Seletskiy, Polytechnique Montréal (Salon A)
CanadaEU consortium on Midinfrared quantum sensing
16h15 Mrs. Fran Delhoume (Salon A)
EDI activity : Microagression at the working place
17:15 Poster session with refreshments (Salon C)
19:30 INTRIQ dinner (Knowlton room)
8:30 Chinmay Nirkhe, IBM quantum, Cambridge (Salon A)
NLTS Hamiltonians from good quantum codes
9:30 Jonathan Durandau, Université de Sherbrooke (Salon A)
Quantum Circuit Compilation and Quantum Computer Architecture
9:50 Coffee break (Salon C)
10:20 Monika Aidelsburger, Munich University (Salon A)
Quantum simulation of Floquet topological phases with ultracold atoms
11:20 Tami PeregBarnea, McGill University (Salon A)
Majorana fermions, where to find them and how to use them
12:00 Lunch (Knowlton room)
13:30 Roger Melko, Perimeter Institute (Salon A)
Quantum Simulation and Rydberg Atom Arrays
14:30 Coffee break (Salon C)
15:00 Karthik Chinni, Polytechnique Montréal (Salon A)
Trotter errors from dynamical structural instabilities of floquet maps
in quantum simulation
15:30 Michael Hilke, McGill University (Salon A)
Molecular single photon sources for quantum communication
and enhanced sensing
16:10 Closing remarks
Quantum Optics Group
Munich University
Quantum simulation of Floquet topological phases with ultracold atoms
Wellcontrolled synthetic quantum systems, such as ultracold atoms in optical lattices, offer intriguing possibilities to study complex manybody problems in regimes that are beyond reach using stateoftheart classical computations. The basic idea is to construct and use a wellcontrolled quantum manybody system in order to study its in and outofequilibrium properties and potentially use it to develop more efficient tailored numerical methods that can then be applied to other systems that are not directly accessible with the simulator.
An important future quest concerns the development of novel experimental techniques that allow us to expand the range of models that can be accessed. I will demonstrate this using the example of topological lattice models, which in general do not naturally appear in coldatom experiments. I will show how the technique of periodic driving, also known as Floquet engineering, facilitates their realization and show how chargeneutral atoms in lattices can mimic the behavior of charged particles in the presence of an external magnetic field. A key ingredient for quantum simulation is the degree of control one has over the individual particles and the microscopic parameters of the model. We have recently succeeded to not only use the technique of periodic driving to emulate physical systems that we know exist in nature, but to take this idea one step further and realize completely new topological regimes that do not have any static analog.
Department of Physics
University of Ottawa
Structured Photons – Their Application in Quantum Photonics
Photons, the quanta of light, possess several different degrees of freedom, e.g., frequency, polarisation, spatial and temporal modes, which can be used as platforms for quantum information applications. Polarisation, corresponding to the vectorial nature of light, is bidimensional, and thus can represent ‘0’ and ‘1’ in the digital world. Unlike polarisation, transverse and temporal modes would provide an unbonded vector space and could be used to extend the alphabet beyond the ‘0’s and ‘1’s to any arbitrary integer numbers. Photons in superposition states of these different degrees of freedom are known as Structured Photons. In the classical regime, structured light has found tremendous applications, e.g., overcoming the diffraction limit (STED microscopy), for optical spanners, communication multiplexing, and generating nontrivial 3D topologies such as Möbius, ribbons and knots. In the quantum domain, structured photons may be used to realise higherdimensional states, and thus are employed in quantum communication, computation, and simulation applications.
The recent progress, challenges, and applications of structured photons in modern photonics, as well as their applications in highdimensional quantum communication, e.g., freespace, underwater, fibre and curved spacetime, links and their security analysis, will be the subject of my talk.
EDI activity: Microagressions at the working place
Fran holds a master's degree in Organizational Development from HEC Montréal and has completed a short program in DiversityEquityInclusion Management at UQAR. She is a neuro inclusion consultant, a course lecturer at Université de Sherbrooke and a DEI analyst with the consulting firm URelles. Her master's thesis, which was received with distinction, questions the underlying foundations of inclusion practices in the workplace for neurodivergent people. She also cohosts the podcast Les Neurodivertissantes, which aims to promote, explain and share expertise and knowledge about neurodiversity in the workplace.
Despite efforts to embrace diversity, equity and inclusion (DEI), members of minority groups continue to experience bias, inequities, microaggressions, and discriminatory experiences in the workplace. Taking place in the daytoday, these experiences are correlated to decreased satisfaction, burnout and depression, work disengagement, higher turn over and other health and social issues. More inclusive workplaces are instead associated with greater satisfaction and retention, improved engagement, higher sense of belonging and increased innovation. In this presentation, we provide a comprehensive look at what microaggressions are and their impacts. It also looks at the role and accountability of the ecosystem and its members in the face of microaggressions, as well as strategies that can be deployed at the individual and organizational levels.
Perimeter Institute
Quantum Simulation and Rydberg Atom Arrays
One major goal of the current generation of quantum devices is to “simulate” (or emulate) the Hamiltonians found in condensed matter and material systems. Such quantum simulation strategies are particularly important in cases where it is challenging to simulate these systems with traditional computational tools, such as quantum Monte Carlo or tensor network methods  numerical schemes that have been under development for decades. Recently, the rapidlyadvancing field of machine learning has introduced a host of new methods suitable for this task, involving neural network architectures and datadriven learning strategies.
In this talk, I will discuss the complementary role of experimental and in silico quantum simulations through the lens of machine learning, using the example of presentday Rydberg atom quantum computers. In particular, I will illustrate the utility of machine learning methods to leverage data from real experiments, and speculate on the future of scientific discovery in quantum manybody simulators that hybridize traditional and datadriven approaches.
IBM quantum, Cambridge
NLTS Hamiltonians from good quantum codes
The quantum PCP conjecture is one of the central open questions in quantum complexity theory. It asserts that calculating even a rough approximation to the ground energy of a local Hamiltonian is intractable even for quantum devices. The widely believed separation between the complexity classes NP and QMA necessitates that polynomial length classical proofs do not exist for calculating the ground energy. This further implies that lowenergy states of local Hamiltonians cannot be described by constant depth quantum circuits.
The "Nolowenergy trivial states (NLTS)" conjecture by Freedman and Hastings posited the existence of such Hamiltonians. This talk will describe a line of research culminating in a proof of the NLTS conjecture by Anshu, Breuckmann, and Nirkhe. The construction is based on quantum error correction and in the talk, I will elaborate on how error correction, local Hamiltonians, and lowdepth quantum circuits are related.
Postdoc, Polytechnique Montréal
Director: Nicolas Quesada
Trotter errors from dynamical structural instabilities of floquet maps in quantum simulation
We study the behavior of errors in the quantum simulation of spin systems with longrange multibody interactions resulting from the TrotterSuzuki decomposition of the timeevolution operator. We identify a regime where the Floquet operator underlying the Trotter decomposition undergoes sharp changes even for small variations in the simulation step size. This results in a time evolution operator that is very different from the dynamics generated by the targeted Hamiltonian, which leads to a proliferation of errors in the quantum simulation. These regions of sharp change in the Floquet operator, referred to as structural instability regions, appear typically at intermediate Trotter step sizes and in the weakly interacting regime, and are thus complementary to recently revealed quantum chaotic regimes of the Trotterized evolution. We characterize these structural instability regimes in pspin models, transversefield Ising models with alltoall pbody interactions, and analytically predict their occurrence based on unitary perturbation theory. We further show that the effective Hamiltonian associated with the Trotter decomposition of the unitary timeevolution operator, when the Trotter step size is chosen to be in the structural instability region, is very different from the target Hamiltonian, which explains the large errors that can occur in the simulation in the regions of instability. These results have implications for the reliability of nearterm gatebased quantum simulators, and reveal an important interplay between errors and the physical properties of the system being simulated.
Professor, McGill University
Decoherence and open quantum systems
In this talk, I will give a brief introduction to the physics of decoherence and quantum dynamics, along with methods for noise mitigation (e.g., dynamical decoupling). The emphasis will be on applications in spectroscopy, qubit readout, and quantum computing.
PhD student, Université de Sherbrooke
Director: Yves BérubéLauzière
Quantum Circuit Compilation and Quantum Computer Architecture
As the technology of qubit and the number of quantum algorithms grow, the next great objective of quantum engineering is an extensible quantum computer. Yet, multiple problems arise, the first one being the qubit connectivity problem. This problem is caused by different characteristics of the quantum qubit, such as the noncloning theorem.
In this presentation, we will present and characterize the connectivity problem on two different types of qubits, superconducting and shuttled trapped ions, using two existing machines as an example, the IBM computer and the SchmidtKaler group computer. We will analyze the connectivity of these machines and propose some solutions that we found in our research.
Professor, McGill University
Molecular single photon sources for quantum communication and enhanced sensing
The pioneering experiments by Hanbury and Twiss are considered by many as the beginnings of quantum optics. These experiments are now particularly relevant in the context of quantum photonics and the characterization of single photon sources. After introducing these experiments and concepts, I will discuss molecular single photon sources, which are rapidly emerging as highly competitive contenders for quantum photonics. They combine the tunability and malleability typically associated with semiconductor based systems, such as quantum dots, and the high purity typically found in atomic systems. Here I will focus on a particular molecule/nanocrystal (BDT/antracene) hybrid system that exhibits a very high, on demand, single photon emission purity, even at room temperature. This system can easily be processed and integrated into various photonic and sensing applications. Two main applications will be discussed in more detail: (1)ambient quantum key distribution [1] with concrete advantages over conventional attenuated laser pulses and (2) local (10100mnm) contact less temperature sensing at cryogenic temperatures. This is particularly interesting when all other techniques fail. This work was done in collaboration with the Toninelli group at LENS and theUniversity of Florence.
[1] G.Murtaza, et al. arXiv:2202.12635 (2022)
Postdoc, Polytechnique Montréal
Director: Nicolas Quesada
Waveguided sources of consistent, singletemporalmode squeezed light: the good, the bad, and the ugly
We study the oretically how the temporal mode structure of squeezed states generated by a parametric waveguided source is modified when driven by pumps of different brightness but identical profiles. We find that the temporal modes of these squeezed states are partially mismatched and thus distinguishable, which is undesirable when using these states as resources for quantum computing or heralded state generation. By studying common frequency filtering techniques used experimentally, we find that although one can regain indistinguishability it comes at the price of potentially greatly reducing the purity of the state. We consider three different source configurations: unapodized single pass, apodized single pass, and apodized double pass. We find that the double pass configuration produces better results with more indistinguishable states.
Postdoc, Polytechnique Montréal
Director: Denis Seletskiy
Simultaneous detection of field quadratures in the timedomain via electrooptic sampling
Analysis of quantum optical states is typically performed using techniques of homodyne detection, where the superposition of the quantum state under study and a classical reference at the same frequency is registered in a squarelaw detector. Due to the lack of quantumlimited sources and efficient detectors, progress with the homodyne characterization of quantum states in the midinfrared (midIR) has been stagnant. Recently, a technique of electrooptic sampling has established itself as the frontier of ultrafast photonics in the midinfrared range, and recent experiments demonstrated the detection of midIR quantum fields, including bare vacuum, directly in the time domain. The temporal resolution comes from the duration of the gating function, commonly reaching 6 fs (1 fs = 10^15 seconds). Here we consider a possibility to efficiently use the entire bandwidth of the gating function to accomplish simultaneous detection of both field quadratures. Motivated by the understanding of the mode structure of the amplitude and Hilbert transform quadratures, we propose multiplexing and modematching operations on the gating function to extract full quantum information on both quantities, simultaneously. The proposed experiment is poised to open a novel path toward quantum state tomography directly in the time domain, promising novel applications toward timedomain quantum spectroscopy and novel explorations in relativistic quantum information.
Professor. McGill University
Majorana fermions, where to find them and how to use them
Majorana fermions have been proposed as potential building blocks of qubits already in 1997. However, despite many efforts to realize them in experiments, they have not been identified without doubt yet. In this tutorial we will go over some simple models of topological superconductivity which give rise to Majorana fermions. We will also discuss proposals for realizing Majoranahosting systems and Majoranabased qubits and discuss some recent experiments.
Professor, Polytechnique Montréal
Subject to be announced
PhD student, Université de Sherbrooke
Director: Stéfanos Kourtis
Discrete optimization inthe MPSMPO language
In discrete optimization problems, one usually asks for an optimal object from a finite set. Suchproblems appear in many fields ranging from logistics to quantum error correction. Many of these are NPcomplete, making exact solutions too hard to find and thus leaving a battle field for different approximate algorithms. In the current study, we show how to marry such probblems with tensor networks and show several relevant example. The code for the study is available as a python package.
PhD student, Université de Sherbrooke
Director: Michel PioroLadrière
Subject to be annouced
Master student, Université d'Ottawa
Director: Anne Broadbent
Coset State Uncloneability to ReceiverIndependent QKD
We construct a receiverindependent quantum key distribution (QKD)scheme, which strengthens the notion of onesided device independent QKD of Tomamichel, Fehr, Kaniewski, and Wehner [NJP 2013] by also permitting the receiver's classical device to be untrusted. Explicitly, the sender remains fully trusted while only the receiver's communication is trusted. We provide a construction that achieves the same asymptotic error tolerance as the scheme of Tomamichelet al.
To show security, we prove an extension of the MoE property of coset states introduced byColadangelo, Liu, Liu, and Zhandry [Crypto 2021]. In our stronger version, the player Charlie also receives Bob's answer prior to making his guess, thus simulating a party who eavesdrops on an interaction. To make use of this property, we express it as a new type of entropic uncertainty relation which arises naturally from the structure of the underlying MoE game.
PhD student, Polytechnique Montréal
Director: Oussama Moutanabbir
Subject to be annouced
PhD student,Université de Sherbrooke
Director: Bertrand Reulet
Fluctuation Loops in Microwave circuits
Study of the outofequilibrium properties of a circuit using thermal noise as a probe.
Master student, Université de Sherbrooke
Director: Bertrand Reulet
Subject to be annouced
PhD student, Université de Sherbrooke
Director: Bertrand Reulet
Detection of Higgs mode in a superconducting wire via impedance measurements in the microwave domain
Microwave investigation of Higgs Mode in a superconducting wire. Higgs mode in superconductors is an analogous of the Higgs boson in high energy physics that has been predicted by Anderson in the late 50s [1]. Its detection is usually difficult because of its weak coupling with electromagnetic fields. However, a recent theory predicted a huge increase of this coupling in the presence of a DC current, which translates into an anomaly in the complex conductivity at frequencies of the order of 2Δ [2]. Observation of Higgs modes in superconductors have been performed in the THz range [3]. A study in the microwave range could enable new measurement such as nonlocal conductivity to probe its propagation. We studied Titanium samples for which 2Δ is of the order of 1030 GHz and can be tuned with the sample thickness. In this experiment we present a precise and quantitative measurement of the high frequency complex impedance of a superconducting wire in the microwave range. In the absence of DC current, we compare our results with BCS theory at equilibrium. With current we observe a feature at frequency2Δ which behaves as predicted in [2] with a width much larger than expected. This experimentis the first step toward the integration of Higgs mode in electronic circuit.
[1] Anderson PW. 1958. Phys. Rev. 112:1900–16
[2] A. Moor and al., Amplitude Higgs Mode and Admittance in Superconductors with a Moving Condensate, PRL 118, 047001 (2017)).
[3] Matsunaga R, Hamada YI, Makise K, Uzawa Y, Terai H, et al. 2013. Phys. Rev. Lett. 111:057002
PhD student, Polytechnique Montréal
Director: Nicolas Quesada
Validating the USTC Gaussian boson sampling experiment against classical mixtures of coherent states hypothesis
Recently, Zhong et al. have performed Gaussian boson sampling experiments using photonic circuits with up to 144 modes and threshold detectors. The samples produced in these experiments have been validated against several classical simulation strategies, such as sampling from probability distributions corresponding to thermal states or distinguishable photons. In this work we propose an alternative validation hypothesis that uses the probability distribution of mixtures of coherent states sent into a lossy interferometer. These mixtures result in classical Gaussian states with vacuum fluctuations in one quadrature and larger fluctuations in the other. To test this hypothesis, we compute the cumulants of the proposed distribution up to fourth order and compare them with the results obtained from the experimental samples and the ground truth distribution of the experiment (namely, the probability distribution of twomode squeezed states sent into a lossy interferometer). We also calculate crossentropy differences between the alternative and ground truth distributions, as well as between samples from the alternative distribution and experimental samples. We find that for the experiments with larger photon density, which are in the quantum advantage regime, the cumulants do not tell the ground state and alternative distributions apart. Additionally, the crossentropy differences indicate that the alternative hypothesis is a better description of the experimental data than the ground truth hypothesis. These results suggest that the results of the experiment can be efficiently reproduced with classical sampling algorithms.
PhD student, McGill University
Director: Bill Coish
NonMarkovian transient spectroscopy in cavity QED
We theoretically analyze measurements of the transient field leaving a cavity as a tool for studying nonMarkovian dynamics in cavity quantum electrodynamics (QED). Combined with a dynamical decoupling pulse sequence, transient spectroscopy can be used to recover spectral features that may be obscured in the stationary cavity transmission spectrum due to inhomogeneous broadening. The formalism introduced here can be leveraged to perform in situ noise spectroscopy, revealing a robust signature of quantum noise arising from noncommuting observables,a purely quantum effect.
Intern student, McGill University
Director: Michael Hilke
Subject to be annouced
Master student, Université de Sherbrooke
Director: Mathieu Juan
Subject to be annouced
Master student, Université de Shebrooke
Director: Dave Touchette
Improving Qubit Routing with EPR Pairs
PhD student, Université de Sherbrooke
Director: Eva DupontFerrier
Subject to be annouced
PhD candidat, Université de Sherbrooke
Director: Michel PioroLadrière
Realtime quantum dot stability diagram measurement using onthefly generated waveforms
Stability diagrams are essential to understand the energy landscape of the quantum dots and tune them into the spinqubit regime, but the voltage space to cover increases significantly with the number of quantum dots. While many advanced measurement techniques were proposed in the last few years to minimize the number of measurements needed to extract valuable information, another approach is to speed up the measurements themselves. Therefore, Keysight’s Quantum Engineering Toolkit (QET) was used to program the experimental routines inside the onboard fieldprogrammable gate arrays (FPGAs). While the programming of those routines takes time and specific knowledge, they run with minimal communications with the host computer which allows high processing speeds. With this approach, we achieve stability diagram measurements in around 30 ms and virtual gates calculations in under 100 ns. The flexibility of the FPGA programming also allows the routines to be adapted to more complex measurements that may include accelerated machine learning or statistical models. Those tools are a first step towards the scalable control of spin qubits using cryogenic electronics.
PhD student, McGill University
Director: Kartiek Agarwal
Subject to be annouced
Professonal & PhD Student, Université de Sherbrooke
Director: Michel PioroLadrière
Intern student, McGill University
Director: Lilian Childress
Improving the Sensitivity of NV Magnetometry
PhD student, Université de Sherbrooke
Director: Stéfanos Kourtis
Subject to be annouced
PhD student, McGill University
Director: Lilian Childress
Coupling Colour Centers in Diamond to Fiber Microcavities
Color centers in diamond are promising solidstate spinqubit systems for quantum information thanks to their atomlike spinoptical properties. Two prospective candidates are the nitrogenvacancy (NV) and germaniumvacancy (GeV). Current implementations with the NV center are restricted by its low emission rate (3%) into its coherent transition and spectral diffusion. In turn, the use of the GeV is limited by its spinorbit interaction necessitating lowtemperature operation. We present our current results in coupling a fiberbased open microcavity (measured finesse of F~8000) to a GeV at ~ 15K. Achieving a reduced lifetime of 1.7+/0.1 ns (bare 6 ns) and an estimated Purcell Enhancement of the zerophonon line of ~24.