Events

IQC, CS, & MATH seminar - Eric Culf, University of Waterloo 

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

Problems based on the structure of graphs -- for example finding cliques, independent sets, or colourings -- are of fundamental importance in classical complexity. It is well motivated to consider similar problems about quantum graphs, which are an operator system generalisation of graphs. Defining well-formulated decision problems for quantum graphs faces several technical challenges, and consequently the connections between quantum graphs and complexity have been underexplored.

In this work, we introduce and study the clique problem for quantum graphs. Our approach utilizes a well-known connection between quantum graphs and quantum channels. The inputs for our problems are presented as quantum channels induced by circuits, which implicitly determine a corresponding quantum graph. We also use this approach to reimagine the clique and independent set problems for classical graphs, by taking the inputs to be circuits of deterministic or noisy channels which implicitly determine confusability graphs. We show that, by varying the collection of channels in the language, these give rise to complete problems for the classes NP, MA, QMA, and QMA(2). In this way, we exhibit a classical complexity problem whose natural quantisation is QMA(2), rather than QMA, which is commonly assumed.       

To prove the results in the quantum case, we make use of methods inspired by self-testing. To illustrate the utility of our techniques, we include a new proof of the reduction of QMA(k) to QMA(2) via cliques for quantum graphs. We also study the complexity of a version of the independent set problem for quantum graphs, and provide preliminary evidence that it may be in general weaker in complexity, contrasting to the classical case where the clique and independent set problems are equivalent.       

This talk is based on work with Arthur Mehta (arxiv.org/abs/2309.12887)

IQC Seminar - Jong-Souk Yeo, Yonsei University

Quantum Nano Centre, 200 University Ave West, Room QNC 0101
Waterloo, ON, CA N2L 3G1

Biomimetic or nature-Inspired technologies are referring to the emerging fields where innovations are strongly inspired by the wisdom from nature or biological systems. Multiple levels of approaches are feasible from nature-inspiration – adaptation of how nature works, adoption of what nature provides, or replication of natural processes and functionalities for eco-friendly, sustainable, and highly efficient technologies. In this talk, nature-inspired approaches will be introduced for the nano-bio and nano-IT convergence research in the areas of nanostructure-cell interactions [1], nano-bio sensorics [2], biomimetic optical nanostructures [3], stretchable electronics [4], quantum plasmonics [5], and neuromorphic semiconductor technologies. Along with the research, recent efforts at Yonsei University will be introduced about the School of Integrated Technology where research and education are organically integrated for the technology convergence, and Yonsei Science Park where innovation ecosystem is established for IT-Bio Cluster Hub hosting Global Bio Campus and IBM quantum computer. This research was supported by the MSIT (Ministry of Science and ICT), Korea, under the ICT Consilience Creative program (IITP-2019-2017-0-01015) supervised by the IITP (Institute for Information & communications Technology Planning & Evaluation), the Ministry of trade, Industry and Energy (MOTIE) and Korea Institute for Advancement of Technology (KIAT) through the International Cooperative R&D program (Project No. P0019630) and by the Human Frontier Science Program (RGP0047/2019).

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