Events

Robin Kothari, Microsoft Research (PLEASE NOTE NEW DATE AND TIME)

We use the polynomial method to prove optimal or nearly optimal lower bounds on the quantum query complexity of several problems, resolving open questions from prior work. The problems studied include k-distinctness, image size testing, k-junta testing, approximating statistical distance, approximating Shannon entropy, and surjectivity.​ Paper available at https://arxiv.org/abs/1710.09079. This is joint work with Mark Bun and Justin Thaler.

Keysight's Quantum Engineering Toolkit: A commercial, customizable integrated control and test system

Presented by guest speaker Nizar Messaoudi, Keysight Technologies Application Engineer

With traditional classical complementary metal oxide semiconductor (CMOS) computing struggling to keep up with Moore’s law, interest in quantum computing has exploded and the University of Waterloo is at the centre of this technological revolution.

PhD Seminar

Chunhao Wang, PhD candidate

David R. Cheriton School of Computer Science

We present a quantum algorithm for simulating the dynamics of Hamiltonians that are not necessarily sparse. Our algorithm is based on the assumption that the entries of the Hamiltonian are stored in a data structure that allows for the efficient preparation of states that encode the rows of the Hamiltonian. We use a linear combination of quantum walks to achieve a poly-logarithmic dependence on the precision. 

Felix Leditzky, University of Colorado, Boulder

Port-based teleportation (PBT) is a variant of the well-known task of quantum teleportation in which Alice and Bob share multiple entangled states called "ports". While in the standard teleportation protocol using a single entangled state the receiver Bob has to apply a non-trivial correction unitary, in PBT he merely has to pick up the right quantum system at a port specified by the classical message he received from Alice.

The Creative Destruction Lab (CDL) is hosting a half-day symposium to discuss recent advances in Quantum Machine Learning, its near-term industry applications, and opportunities for commercialization with private financing as a technology startup.

Jan Haase, Universität Ulm

Whenever one is tempted to employ a quantum system for any kind of applications, the focus usually lies on two properties setting it apart from a system described by a classical theory, namely the coherent superposition of different quantum states and entanglement between two ore more constituents forming the system.

Crystal Senko: Ion traps and multi-level quantum systems

I give an overview of trapped ion quantum information experiments and discuss prospects for implementing multi-valued quantum logic using trapped ions.

Dagmar Bruss, University of Duesseldorf

The resource theory of quantum coherence studies the off-diagonal elements of a density matrix in a distinguished basis, whereas the resource theory of purity studies all deviations from the maximally mixed state. We establish a direct connection between the two resource theories, by identifying purity as the maximal coherence, which is achievable by unitary operations. The states that saturate this maximum identify a universal family of maximally coherent mixed states.

David P. Pappas, National Institute of Standards and Technology (NIST)

A brief history and overview of the requirements to guide the research and development for high-coherence superconducting quantum circuits will be given. The main focus will be on materials development at NIST. Topics will include identifying and mitigating loss due to amorphous two-level systems at interfaces and how to scale the fabrication of small aluminum-oxide tunnel junctions. The junctions were studied with atom probe microscopy to get an understanding of where the oxidation occurs.

The number theory of quantum information

Jon Yard, IQC

Abstract: Quantum-mechanical amplitudes and unitaries are typically expressed over the complex numbers. Because there is a continuum of complex numbers, classical computations of quantum systems generally utilize finite-precision approximations by rational numbers.