Events

PhD Seminar: Olivia Di Matteo

Quantum random-access memories (qRAM) are required by numerous quantum algorithms. In many cases, qRAM queries are the limiting factor in the implementation of these algorithms. In the limit of a large number of queries, there will be a massive resource overhead, as in this regime it is not possible to bypass the need for active error correction. In this talk, I will present our work towards quantifying this overhead. We will explore a variety of different qRAM circuits designed to query classical bits in superposition.

Stacey Jeffery, QuSoft, Research Centre for Quantum Software

A random walk on a graph, P, with marked vertex set M, finds a marked vertex using a O(HT(P,M)) steps of the walk, where HT(P,M) is the hitting time. Previous quantum algorithms could detect the presence of a marked vertex in O(sqrt{HT(P,M)}) steps, or find a marked vertex in O(sqrt{HT(P,M)}) steps if M contained at most one vertex, but the case of finding in the presence of multiple marked vertices was left as an open problem.

Stefan Frick, University of Bristol, UK

Rangefinding has many applications in navigation, civil engineer, construction, military, surveillance and security. Most commonly rangefinders estimate the distance to an object by measuring the time of flight of light for the journey to and returning from the target. Conventional techniques use lasers for illumination in state of the art rangefinding systems. However, the particular state of light lasers produce makes them easy to detect.

Impacts of relativity on localizability and vacuum entanglement

Master's Candidate: Maria Papageorgiou 

Speaker: Neil Henderson

Abstract: The patent system provides a monopoly in return for disclosure of new technology. The disclosures (patent applications) are published and classified by technology to provide an extensive global resource available on line. Want to know how many patent applications Apple has for quantum cryptography? Who else is working in your area ? Does anyone hold a dominant position or are the rights widely distributed?

Giovanni Fanchini, Western University

In this talk, we will review the use of thin films of organic polyradicals – organic polymers with one unpaired electron per monomer [1] – for memory devices and other applications. Although memory devices based on radical polymers have been often proposed, their stability was frequently limited to a few writing cycles, despite the excellent quality of the active layer.

Alexander Belovs, University of Latvia

This talk reflects on recent research in progress with Andras Gilyen. Over the years, there have been a number of papers dealing with quantum algorithms testing some properties of classical probability distributions. Our goal is to understand what is the right way for quantum algorithms to access the distribution. There is a number of possible models, and we analyse their mutual strength.

Frederic Magniez, Université Paris Diderot

We describe a new quantum paradigm, that we call Quantum Chebyshev’s inequality, to approximate with relative error the mean of any random variable with a number of quantum samples that is linear in the ratio of the square root of the variance to the mean. Classically the dependency is quadratic. To illustrate this method, we apply it to the approximation of frequency moments in the multi-pass streaming model, and to the approximation of the number of edges and triangles in the quantum graph query access model.

Spontaneous Raman emission in cold atoms inside a hollow-core waveguide

Taehyun Yoon, Institute for Quantum Computing

Cold atoms confined inside hollow-core waveguides enable strong-matter interactions, thus offer a unique platform for studies of quantum and non-linear optics. We developed an experimental system that traps cesium atoms in a magneto optical trap (MOT) and loads these atoms into a hollow core photonic crystal fiber using a dipole trap at cesium magic wavelength (935 nm), which removes the AC-Stark shift of the optical transition and suppresses the inhomogeneous broadening.

Speaker: Heather Hoff

Abstract: Software is a key asset of any new business. How do you protect the results of weeks or months of hard labour? Who owns the software and how do I mange its development to ensure its inherent value is maintained? Should I use Open Source, or even contribute to Open Source? What are the benefits and how does this measure up against the risks?