Events

IQC/Physics Special Seminar - Loren Swenson, D-Wave Systems

I will introduce quantum annealing as a technique for harnessing quantum mechanics to solve hard problems. The design of a quantum annealing processor based on superconducting flux qubits, some of the challenges we have encountered in constructing it, and measurements confirming the role of quantum mechanics in such processors will be presented. Finally, I will briefly discuss recent benchmarking and simulation results using the D-Wave 2000Q processor.

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.

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

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.

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.

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.

Rakesh Tiwari, McGill University

Quantum phenomena have the potential to speed up the solution of hard optimization problems. For example quantum annealing, based on the quantum tunnelling effect, has recently been shown to scale exponentially better with system size as compared with classical simulated annealing. However, current realizations of quantum annealers with superconducting qubits face two major challenges. First, the connectivity between the qubits is limited, excluding many optimization problems from a direct implementation.

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.

Ana Asenjo Garcia - California Institute of Technology

Dissipation is a pervasive problem in many areas of physics. In quantum optics, losses curb our ability to realize controlled and efficient interactions between photons and atoms, which are essential for many technologies ranging from quantum information processing to metrology. Spontaneous emission - in which photons are first absorbed by atoms and then re-scattered into undesired channels - imposes a fundamental limit in the fidelities of many quantum applications, such as quantum memories and gates.