Quantum Research Seminars Toronto consist of two 30 min talks about some Quantum Computation topic. Seminars are given by high-level quantum computing researchers with the focus on disseminating their research among other researchers from this field. We encourage to attend researchers regardless of their experience as well as graduate and undergraduate students with particular interest in this field. Basic notions on quantum computing are assumed, but no expertise in any particular subject of this field.

In this 16th series of seminars, the speakers will be Claire L. Edmunds (University of Innsbruck) and Sascha Heußen / Lukas Postler (RWTH Aachen University / University of Innsbruck). Their talks are titled "Error characterisation and reduction in trapped-ion quantum computers" and "Demonstration of fault-tolerant universal quantum gate operations", respectively.

We will send a Zoom link to those who register for this event 2 days, 2 hours and 10 min before the event starts.

The event recording, slides and chat history will be published in our Youtube channel and sent to the registered participants.

Looking forward to seeing you all!

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Talk 1:

Title: Error characterisation and reduction in trapped-ion quantum computers

Abstract:

Quantum technology is a rapidly developing field across academia, government and industry that seeks to exploit the bizarre and unintuitive physics that occurs on microscopic scales. This technology will enable the exploration of a wide range of topics – from solving complex mathematical problems or simulating quantum properties underlying natural materials, to improving security by encoding and communicating information privately. When building quantum devices, the sensitivity that makes these systems so powerful is also the cause of their vulnerability to errors. The feasibility of current devices is limited by the requirement for high fidelity gates with low and uncorrelated errors between gates and qubits. As systems are scaled up in both the number of qubits and algorithm length, it becomes increasingly challenging to keep error rates low using hardware alone.

Quantum control suppresses errors to a level that exceeds limitations set by physical hardware when using standard gate implementations. By characterising the errors affecting a quantum device and tailoring robust, dynamic control solutions, we are able to achieve superior performance compared to the baseline operation. In this presentation, I will demonstrate the identification, reduction and homogenisation of errors across a trapped-ion qubit register, reducing overhead and pre-conditioning the system for quantum error correction.

About the speaker:

Dr. Claire Edmunds works at the Universität Innsbruck in the Quantum Optics & Spectroscopy group, led by Professor Rainer Blatt. Claire specialises in quantum simulation and quantum control using trapped 40Ca+ ions. In 2021, Claire was awarded a research fellowship with the Erwin Schrödinger Center for Quantum Science and Technology (ESQ) after completing her PhD in experimental quantum physics at the University of Sydney. Her works strives to improve the performance of quantum platforms in realistic laboratory conditions in the path to build reliable quantum computers and simulators.

Talk 2:

Title: Demonstration of fault-tolerant universal quantum gate operations

Abstract:

Quantum computers can be protected from noise by encoding the logical quantum information redundantly into multiple qubits using error correcting codes. When manipulating the logical quantum states, it is imperative that errors caused by imperfect operations do not spread uncontrollably through the quantum register. This requires that all operations on the quantum register obey a fault-tolerant circuit design which, in general, increases the complexity of the implementation. Here, we demonstrate a fault-tolerant universal set of gates on two logical qubits in a trapped-ion quantum computer. In particular, we make use of the recently introduced paradigm of flag fault tolerance, where the absence or presence of dangerous errors is heralded by usage of few ancillary 'flag' qubits. Experimental results are accompanied by numerical simulations based on a generic, architecture-agnostic error model.

About the speaker:

Sascha Heußen is currently a Ph.D. student in the group Prof. Markus Müller at RWTH Aachen working in the field of fault-tolerant quantum error correction. Furthermore he was a visiting researcher at the Institute for Quantum Information and Matter at Caltech and he holds an M.Sc. from TU Dortmund.

Lukas Postler is a Ph.D. student in the group of Prof. Rainer Blatt at the University of Innsbruck. His research is focused on quantum information processing applications in trapped-ion quantum processors. He holds an M.Sc. from the University of Innsbruck.