Events

Live on YouTube

Join us for Quantum Today, where we sit down with researchers from the University of Waterloo’s Institute for Quantum Computing (IQC) to talk about their work, its impact and where their research may lead.

In this special session, we’ll be joined by Joan Arrow and Özge Gülsayin of the Quantum Ethics Project, a team of researchers exploring the intersection of quantum and society. We’ll discuss how to advocate for the responsible and inclusive development of quantum technologies through education and research, and why an ethics lens is important in even the early stages of technological innovation.

Quantum Nano Centre, 200 University Ave West, Room QNC 1201
Waterloo, ON CA N2L 3G1

Two randomly selected audience members will get the opportunity to present their work on the whiteboard for 20-minutes each.

Online webinar through Microsoft Teams

The University of Waterloo and Mitacs will be holding a joint webinar on Thursday, November 23^rd at 10am to share information about their new Globalink Research Award (Quantum stream), which provides funding for bilateral student travel with international university labs.

In this session, Amanda Green and Etienne Pineault, Senior Advisors with Mitacs, will provide information and updates on how to leverage Mitacs funding to build collaborative research projects with international university partners. 

Following the presentation, we will answer your questions about finding a partner, deciding on Mitacs eligibility and navigating program requirements (including how to work with our team to submit successful funding applications). Regan Child, International Grants and Contracts Manager with the Office of Research, will be on hand to offer assistance.

CS/MATH Seminar - Dominic Verdon (University of Bristol)

University of Waterloo, 200 University Ave West, Waterloo ON QNC 1501 + ZOOM

The quantum Boolean satisfiability problem, quantum k-SAT for short, is the quantum analogue of the classical Boolean satisfiability problem. It is QMA_1-complete for k >2, and therefore appears very difficult to solve in general. In this talk I will discuss a property testing approach to quantum k-SAT which, given the promise that an instance of the problem is either (i) satisfiable or (ii) far from satisfiable by a product state, yields a polynomial-time algorithm for deciding which of the two mutually exclusive properties (i) or (ii) holds. To show this we apply some tools from combinatorics, entanglement theory and algebraic geometry. The talk is based on joint work with Ashley Montanaro and Changpeng Shao (https://arxiv.org/abs/2301.10699).

Tight bounds for Pauli channel learning with and without entanglement

Quantum Nano Centre, 200 University Ave West, Room QNC 1201
Waterloo, ON CA N2L 3G1

Quantum entanglement is a crucial resource for learning properties from nature, but a precise characterization of its advantage can be challenging. In this work, we consider learning algorithms without entanglement as those that only utilize separable states, measurements, and operations between the main system of interest and an ancillary system. Interestingly, these algorithms are equivalent to those that apply quantum circuits on the main system interleaved with mid-circuit measurements and classical feedforward. Within this setting, we prove a tight lower bound for Pauli channel learning without entanglement that closes the gap between the best-known upper bound. In particular, we show that Θ(n^2/ε^2) rounds of measurements are required to estimate each eigenvalue of an n-qubit Pauli channel to ε error with high probability when learning without entanglement. In contrast, a learning algorithm with entanglement only needs Θ(1/ε^2) copies of the Pauli channel. Our results strengthen the foundation for an entanglement-enabled advantage for Pauli noise characterization. We will talk about ongoing experimental progress in this direction.

Reference: Mainly based on [arXiv: 2309.13461]

Optimization of the Optical Infrastructure and Trapping Potential for a Quantum Processor Based on Trapped Barium Ions

Quantum-Nano Centre, 200 University Ave West, Room QNC 2101
Waterloo, ON CA N2L 3G1

Supervisor: Kazi Rajibul Islam

Creating and probing laser-cooled atomic ensembles inside a hollow-core optical fibre

Quantum-Nano Centre, 200 University Ave West, Room QNC 2101
Waterloo, ON CA N2L 3G1

Supervisor: Michal Bajcsy

Development of III-V semiconductor surface quantum wells for hybrid superconducting device applications

Quantum-Nano Centre, 200 University Ave West, Room QNC 1201
Waterloo, ON CA N2L 3G1

Supervisor: Jonathan Baugh

Unruh phenomena and thermalization for qudit detectors

Quantum-Nano Centre, 200 University Ave West, Room QNC 1201 Waterloo, ON CA N2L 3G1

The Unruh effect is the flat space analogue to Hawking radiation, describing how an observer in flat spacetime perceives the quantum vacuum state to be in a thermal state when moving along a constantly accelerated trajectory. This effect is often described operationally using the qubit-based Unruh-DeWitt detector.

We study Unruh phenomena for more general qudit detectors coupled to a quantized scalar field, noting the limitations to the utility of the detailed balance condition as an indicator for Unruh thermality of higher-dimensional qudit detector models. We illustrate these limitations using two types of qutrit detector models based on the spin-1 representations of SU(2) and the non-Hermitian generalization of the Pauli observables (the Heisenberg-Weyl operators).

[2309.04598] Unruh phenomena and thermalization for qudit detectors (arxiv.org)

CS Math Seminar - Kewen Wu, UC Berkeley (ZOOM + in person)

200 University Ave W. Waterloo On. N2G 4K3 QNC 1201

Motivated by limitations on the depth of near-term quantum devices, we study the depth-computation trade-off in the query model, where the depth corresponds to the number of adaptive query rounds and the computation per layer corresponds to the number of parallel queries per round. We achieve the strongest known separation between quantum algorithms with r versus r−1 rounds of adaptivity. We do so by using the k-fold Forrelation problem introduced by Aaronson and Ambainis (SICOMP'18). For k=2r, this problem can be solved using an r round quantum algorithm with only one query per round, yet we show that any r−1 round quantum algorithm needs an exponential (in the number of qubits) number of parallel queries per round.

Our results are proven following the Fourier analytic machinery developed in recent works on quantum-classical separations. The key new component in our result are bounds on the Fourier weights of quantum query algorithms with bounded number of rounds of adaptivity. These may be of independent interest as they distinguish the polynomials that arise from such algorithms from arbitrary bounded polynomials of the same degree.

Joint work with Uma Girish, Makrand Sinha, Avishay Tal