quantum

Sangil Kwon: Phase in Superfluids and Spontaneously Broken Gauge Symmetry

It is often said that superfluids (including superconductors) can be described by a macroscopic quantum wavefunction and their phase transition can be understood based on the concept of spontaneously broken gauge symmetry. This statement is not, however, trivial at all. In this seminar, I will discuss some conceptual problems that stem from applying the concept of spontaneously broken gauge symmetry to superfluids.

Pavithran Iyer, Université de Sherbrooke

Arbitrary precision quantum control of qubit systems appears to be unobtainable due to environmental influences that manifest themselves as errors in a quantum algorithm. Errors modelled by the probabilistic application of Pauli operators during the computation are convenient for analytical proofs and classical simulation but the level of accuracy of such a model depends on the quantumness of the error source.

Gerard Valentí Rojas - The Institute of Photonic Sciences, Spain

The laws of quantum mechanics have helped scientists to unravel the behaviour of nature at its most fundamental scales. However, quantum phenomena are often difficult to understand and simulations have historically provided a useful framework for their study. Nevertheless, when dealing with large quantum systems or real-time dynamics, the computational cost of numerical simulations can become unfeasible.

Matthew Day, University of Bristol and National Physical Laboratory, UK

Trapped ions are one of the most mature platforms for quantum information processing, quantum-enhanced sensing, and precision spectroscopy. Scaling to large numbers of trapped ions remains an open, technological challenge that would help advance the functionality and usefulness of the platform. The production of ion microtrap arrays, fabricated using MEMS techniques, has provided a key component to this scaling challenge.

Andrew N. Cleland, University of Chicago

Superconducting qubits offer excellent prospects for manipulating quantum information, with good qubit lifetimes, high fidelity single- and two-qubit gates, and straightforward scalability (admittedly with multi-dimensional interconnect challenges). One interesting route for experimental development is the exploration of hybrid systems, i.e. coupling superconducting qubits to other systems.

Colloquium featuring Karl Jansen - NIC/DESY Zeuthen, Germany

The strong interaction of quarks and gluons is described theoretically within the framework of Quantum Chromodynamics (QCD). The most promising way to evaluate QCD for all energy ranges is to formulate the theory on a 4 dimensional Euclidean space-time grid, which allows for numerical simulations on state of the art supercomputers. We will review the status of lattice QCD calculations providing examples such as the hadron spectrum and the inner structure of nucleons.

Tarun Patel: Photocurrent imaging of charge density wave transitions in ultrathin 1T-TaS2  

1T-TaS2 is a layered van-der Waals material which shows multiple charge density wave (CDW) transitions as a function of temperature. Ultrathin flakes fabricated by mechanical exfoliation and protected from oxidation with h-BN capping in inert atmosphere have been shown to retain these transitions.

Ke He, Tsinghua University

The quantum anomalous Hall (QAH) effect is a quantum Hall effect induced by spontaneous magnetization instead of an external magnetic field. The effect occurs in two-dimensional (2D) insulators with topologically nontrivial electronic band structure which is characterized by a non-zero Chern number. The experimental observation of the QAH effect in thin films of magnetically doped (Bi,Sb)2Te3 topological insulators (TIs) paves the way for practical applications of dissipationless quantum Hall edge states.

Brandon Buonacorsi - Modeling the Exchange Interaction in Silicon Quantum Dots

Silicon metal-oxide-semiconductor field effect transistor (MOSFET) quantum dots are promising candidates for scalable quantum computing using electron spin qubits due to their long coherence times, compact size, and ease of integration into existing fabrication technologies.  I will introduce how we fabricate these devices and describe the experimental characterizations we do to check the stability and tunability of our quantum dots.  In a double quantum dot device, two qubit gates are realized

CryptoWorks21 at the University of Waterloo, together with representatives from the Standards Council of Canada (SCC) and the European Telecommunications Standards Institute (ETSI), are proud to present a lunch-time standards session.