Current graduate students

IQC Colloquium featuring Xuedong Hu Department of Physics, University at Buffalo, SUNY

Research on the physical implementation of quantum computing has made dramatic progress over the past decade, spearheaded by superconducting qubits and trapped ion qubits, to the degree that small-scale quantum information processors are now within reach. Studies of semiconductor spin qubits, which have often been considered one of the most promising in the long term from the perspective of scalability, have also yielded some important results in the past decade, demonstrating exceptional coherence properties for single spins confined in quantum dots and donors and high-fidelity single-qubit gates. ...

Young-June Kim: Alpha-RuCl3: a progress report

Abstract: A bond-dependent anisotropic magnetic interaction called the Kitaev interaction can be found in honeycomb lattice materials with strong spin-orbit coupling, which has made a profound impact on quantum magnetism research. In particular, alpha-RuCl3 has been heralded as a realization of the Kitaev quantum spin liquid state, an elusive new state of matter that harbours Majorana fermions. In this talk, I will give a brief overview of the current status of research on alpha-RuCl3 and discuss recent experimental developments and a few surprising findings using ultra-high-quality samples grown in our laboratory. Our samples have minimal stacking faults even at low temperatures, allowing us to determine the low-temperature crystal structure unambiguously. We also found that the magnetic properties are surprisingly sensitive to the inter-layer configuration, giving rise to various magnetic transition temperatures. We also compare low-energy spin-orbit excitations in various Kitaev materials using resonant inelastic x-ray scattering (RIXS). We found that non-local physics is important for describing the spin-orbit excitations in these materials, in contrast to the conventional belief that local Jeff=1/2 physics is sufficient in these compounds.

Math/CS Seminar Featuring Cihan Okay Bilkent University

In modern homotopy theory, spaces are represented by combinatorial models called simplicial sets. Their elegant formulation gives them great expressive power to capture spaces up to homotopy. Simplicial distributions are basic mathematical objects that mix simplicial sets with probabilities. ...

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.

MATH CS Seminar Featuring Maris Ozols, ASSISTANT PROFESSOR UNIVERSITY OF AMSTERDAM QuSoft

Majority vote is a basic method for amplifying correct outcomes that is widely used in computer science and beyond. While it can amplify the correctness of a quantum device with classical output, the analogous procedure for quantum output is not known. We introduce quantum majority vote as the following task: given a product state ∣ψ_1⟩⊗⋯⊗∣ψ_n⟩ where each qubit ∣ψ_i⟩ is in one of two orthogonal states ∣ψ⟩ or ∣ψ^⊥⟩, output the majority state. We show that an optimal algorithm for this problem achieves worst-case fidelity of 1/2 + Θ(1/n). Under the promise that at least 2/3 of the input qubits are in the majority state, the fidelity increases to 1 − Θ(1/n) and approaches 1 as n increases. ...

IQC Colloquium Featuring Dr. Stephanie Simmons - Photonic

The future global quantum internet will require high-performance matter-photon interfaces. The highly demanding technological requirements indicate that the matter-photon interfaces currently under study all have potentially unworkable drawbacks, and there is a global race underway to identify the best possible new alternative. For overwhelming commercial and quantum reasons, silicon is the best possible host for such an interface. Silicon is not only the most developed integrated photonics and electronics platform by far, isotopically purified silicon-28 has also set records for quantum lifetimes at both cryogenic and room temperatures ...