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.

The Quantum Horizons: Quantum Information Science (QIS) Research and Innovation for Nuclear Science award from the U.S. Department of Energy's Office of Nuclear Physics has enabled a new collaboration between researchers who develop technologies for nuclear physics, quantum information science and high-energy physics. 

Yesterday, the Institute for Quantum Computing (IQC) held its first Colloquium of 2023, including an opportunity to connect to our community with pre-presentation coffee and tea, and a fantastic presentation featuring Dr. Stephanie Simmons titled Silicon Colour Centres.

Dr. Raymond Laflamme, founding director of the Institute for Quantum Computing (IQC) at the University of Waterloo, has been named Chair of the National Quantum Strategy’s (NQS) Quantum Advisory Council. The announcement was made today by the Honourable François-Philippe Champagne, Canada’s Minister of Innovation, Science and Industry. Laflamme will work in close collaboration with fellow Chair Dr. Stephanie Simmons, Chief Quantum Officer of Photonic and IQC affiliate. 



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. ...

Cyberattacks and data breaches are an invisible but growing threat that is becoming more commonplace against the landscape of technological growth and development. Quantum cryptography offers data protection in our evolving digital spaces.