Chairs
Professor Sougato Bose, University College London, UK
Professor Sougato Bose, University College London, UK
Professor Sougato Bose has pioneered the study of quantum communications through spin chains, as well as several proposals on generating and probing macroscopic quantum superpositions. More recently, he has suggested a method to detect the quantum nature of gravity through the entanglement of mesoscopic masses. Working in the areas of quantum information, quantum optics and quantum many-body physics, he has published over 150 journal articles, including 34 in Physical Review Letters and three in Nature Communications. He was awarded the Maxwell Medal and Prize of the UK Institute of Physics in 2008, an EPSRC Advanced Research Fellowship 2006–2011, a Royal Society Wolfson Research Merit Award 2007–2012 and an ERC Starting grant 2012–2017. After completing his PhD in 2000 from Imperial College under the supervision of Sir Peter Knight, he held a junior research fellowship at St John's College, Oxford, a postdoctoral fellowship at Caltech, Pasadena, USA. Since 2003 he has been a member of Department of Physics and Astronomy at University College London (UCL).
09:00-09:30
Quantum simulations and quantum networks with trapped ions
Dr Ben Lanyon, Institut für Quantenoptik und Quanteninformation & University of Innsbruck, Austria
Abstract
In the first half Dr Ben Lanyon will present a trapped-ion quantum simulator. His approach is based on a 1D string of trapped atomic calcium ions, between which his group can turn on tunable-range interactions using lasers. He achieved full individual qubit (ion) control and entangled states for up to 20 qubits (N Friis et al., Phys. Rev. X., 2018). Dr Lanyon presents the system capabilities, challenges and recent results on extending the system to 50 qubits. In the second half Dr Lanyon will present his recent results on interfacing these registers of trapped ions with travelling photons. In particular, using cavity-QED techniques the group achieve on demand entanglement between the ion-qubit state and a travelling photon with probability of over 50%. Secondly, he observes that the entanglement remains after the photon travels over 50km of optical fibre (V. Krutyanskiy et al., npj Quantum Information, 2019). This opens up the possibility of entangling these registers of ions, hundreds of kilometres apart and more.
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Dr Ben Lanyon, Institut für Quantenoptik und Quanteninformation & University of Innsbruck, Austria
Dr Ben Lanyon, Institut für Quantenoptik und Quanteninformation & University of Innsbruck, Austria
Ben Lanyon was born in 1981 in the UK and received his undergraduate and Masters degrees in Physics from the University of Warwick, UK, in 2003. In 2009, Ben received his PhD from the University of Queensland, Australia. For his PhD thesis, Ben contributed to developing and experimentally demonstrating new techniques for the field of quantum information science, using single and entangled photons. This work was done in the group of Professor Andrew White. Ben came to Innsbruck in 2009 to carry out research on quantum information science with trapped atomic ions, in the group of Rainer Blatt. Ben has since been awarded a Marie Curie postdoctoral fellowship (2010) and an Austrian Start award (2015). Ben is now setting up his own research team at IQOQI: the Institute for Quantum Optics and Quantum Information. His work focuses on developing and demonstrating new techniques to interface light and matter at the quantum level, to interface different types of quantum systems and to enable the distribution of entanglement over large distances.
09:45-10:15
Quantum dots for quantum simulations
Professor Ruth Oulton, University of Bristol, UK
Abstract
Quantum dots, quantum emitters in a semiconductor matrix, are most often proposed as a bright and efficient source of single photons for many quantum technologies. And, as Professor Ruth Oulton has demonstrated previously, a near-perfect single photon source goes hand-in-hand with potentially deterministic interactions with input photons. However, it is the spin degree of freedom in their ground state which gives them the greatest scope for quantum simulations. Photons input into a QD device can be entangled with the long coherence time spin system, and protocols to produce entangle chains of photons (1D cluster states) have already been demonstrated. Professor Oulton will discuss how one may entangle very long coherence time photons with the spin. Reflecting the long photon from a quantum dot spin precessing in a magnetic field results in a phase modulation of the photon wave function in time, with periodic entanglement resulting. Professor Oulton will discuss the potential of spin-photon entangled states as building blocks for analogue and digital quantum simulations.
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Professor Ruth Oulton, University of Bristol, UK
Professor Ruth Oulton, University of Bristol, UK
Ruth Oulton’s field of research involves the study of nanoscale semiconductor devices that enable the exchange of “quantum” information between a single electron and a single photon. The idea is that they can use the rules of quantum mechanics to perform computing and measurements in a completely new way. She take ideas from quantum theory and information science, bring them together with what we are beginning to understand about semiconductors on the nanoscale, and to make working quantum devices that engineers will use as part of their everyday toolkit. In her recent work she studies single electron spins in atomic-like systems, and studies how the angular momentum of the photon and spin exchange information, and how photonic design can influence this. In other interdisciplinary side projects she studies the role of photonic structures in plants such as seaweed and begonias.
11:00-11:30
Quantum annealing with superconducting flux qubits
Professor Paul Warburton, University College London, UK
Abstract
Quantum annealing makes less stringent demands on qubit coherence than gate-based approaches, thereby enabling proof-of-principle demonstrations of annealers with around 2000 superconducting flux qubits. Furthermore by capacitively shunting the flux qubit and reducing the circulating current one can achieve both high coherence and low leakage, making the flux qubit an excellent approximation to a two-level quantum system. Nevertheless most measurements on experimental annealers are plagued by noise, and the role of coherence in quantum annealing is not currently understood. Professor Paul Warburton will describe his group’s experimental and analytical work on both understanding coherence in flux qubit annealers and how to optimise their use for real-world applications in the presence of noise. They have used the Schrieffer-Wolf transformation to extract the Pauli coefficients from quantum circuit models and developed this technique to investigate non-stoquastic Hamiltonians arising from simultaneous inductive and capacitive qubit interactions. They have analysed the extent to which Landau-Zener-Stückelberg oscillations can be used as a coherence metric in the context of quantum annealing. The group has also developed a new method for embedding real-world problems with high qubit connectivity onto hardware graphs of limited degree and show experimentally that this method outperforms rival embedding techniques for annealers in the presence of noise. The research is based upon work supported by EPSRC (grant reference EP/R020159/1) and the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), via the US Army Research Office contract W911NF-17-C-0050. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the ODNI, IARPA, or the US Government.
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Professor Paul Warburton, University College London, UK
Professor Paul Warburton, University College London, UK
Paul Warburton is Professor of Nanoelectronics at the London Centre for Nanotechnology and the Department of Electronic and Electrical Engineering at University College London. He is interested in both experimental implementations and applications of quantum annealing using superconducting devices. He is involved in designing novel Hamiltonians which reveal the underlying quantumness of small systems of annealed qubits and/or which can be exploited for applications. His group gave the first demonstration of maximum-entropy inference using an experimental quantum annealer, confirming that information can be extracted from the excited states. He is part of the US-government-funded collaboration 'Quantum Enhanced Optimization'.
11:45-12:15
Energy-landscape shaping for quantum simulation with cold atoms and in semiconductors
Dr Sophie Shermer, Swansea University, UK
Abstract
Energy landscape shaping is a way to alter the natural evolution of a quantum system to achieve certain objectives utilising the continuous evolution of the system instead of applying discrete quantum gates and dynamic control. Using spin networks as an abstract model system Dr Sophie Shermer will discuss how to design energy landscapes to control information flow between nodes in various networks. Energy landscape design will be formulated as an optimal control problem and in terms of linear feedback control systems. Various solutions to the optimal control problems arising will be examined in terms of robustness. Robustness of the evolution with regard to uncertainty in system parameters, initial conditions and environmental effects such as decoherence is crucial, and the development of better tools inspired by classical engineering is essential for robust quantum technology. Dr Shermer will discuss classical engineering approaches to robustness and the challenges in applying them to quantum systems, as well as some promising results suggesting that classical limits on robustness need not apply to the latter. Possible implementations of energy landscape control using cold atoms trapped in optical lattices as experimental testbeds for pseudo-spin networks will also be considered.
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Dr Sophie Shermer, Swansea University, UK
Dr Sophie Shermer, Swansea University, UK
Sophie Shermer is an Associate Professor of Physics at Swansea University, UK. She previously held positions as a Cambridge-MIT (CMI) Research Fellow and Advanced Research Fellow of the UK Engineering and Physical Sciences Research Council (EPSRC) at the University of Cambridge, as a Marie Curie Visiting Professor at Kuopio University, Finland, as well as positions at the Open University and the University of Oregon. Sophie’s research interests range from nano-science at the quantum edge and quantum engineering, especially the design, modelling and characterisation of quantum devices and new paradigms for optimal and robust control, to medical physics and imaging.