Hybrid quantum computers: a "one for all and all for one" approach with superconductors and spin ensembles
Professor Klaus Mølmer, University of Aarhus, Denmark
Abstract
Since the 1994 discovery by Peter Shor that a quantum computer may factor large numbers efficiently, the potential for quantum computing has been recognized by a variety of public, strategic, and commercial organizations.
Quantum computing may be implemented with physical components that are already studied extensively in the laboratory: trapped ions, cold atoms, superconducting circuits, liquid and solid state spin ensembles, etc., and elementary gate operations and algorithms have already been demonstrated in experiments.
The basic challenge for quantum computing is to find and control a physical quantum system that offers rapid processing, long-time storage, scalability to a sufficient processor size, and means for intermediate or long distance communication. Since no single quantum system meets all these requirements, the concept of hybrid quantum technologies has emerged, where the different tasks are shared between physical components that are individually optimized for the different functions.
The interfacing of physical systems with very different spatial, temporal and energetic properties presents a big challenge in itself. By means of a recent successful example involving superconducting circuits and atomic spin degrees of freedom I shall give an illustrative example of how that challenge may be met.
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Professor Klaus Mølmer, University of Aarhus, Denmark
Professor Klaus Mølmer, University of Aarhus, Denmark
"Professor Klaus Mølmer obtained his PhD in physics in 1990. His research interests include quantum optics, damping and dissipation in quantum physics, quantum measurements and metrology, cold atom physics and quantum information science. He is very active in science outreach and the author of a popular textbook and several articles in Danish about different aspects of quantum physics. "
NMR classical computation (expt)
Dr Matthias Bechmann, Johannes Kepler University Linz, Austria
Abstract
Nuclear magnetic resonance (NMR) spectroscopy has been very successful, both for its role as spectroscopic tool to determine molecular structure on one side and as a test case for the quantum mechanical description of spins and their dynamics on the other. Precise measurement of the dynamics of spin-system ensembles is today facilitated by a high level of hardware engineering that has been put into the hardware. This all together made NMR also very attractive as a means for researching quantum computing.
Here the potential of such NMR spectrometers to implement classical computational paradigms is demonstrated. This scenario then makes it possible to combine and assess quantum and classical contributions to "computation" in a single experimental set-up.
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Dr Matthias Bechmann, Johannes Kepler University Linz, Austria
Dr Matthias Bechmann, Johannes Kepler University Linz, Austria
"Matthias Bechmann was awarded Dipl.-Phys. 1999 at University of Bayreuth, and Dr rer nat 2005, at Bavarian Research Institute of Experimental Geochemistry and Geophysics, Bayreuth, Germany. He was postdoctoral fellow, University of Dortmund, 2005-2006; postdoctoral fellow, University of York, UK, 2006-2011; experimental officer, NMR center University of York, UK, 2011-2012; and research scientist, Kepler University Linz, AT, 2013-present. Approximately 25 publications and current research interests are: Methodolody of solid-state NMR and its application to biological systems; evolutionary optimisation techniques; and computation by nuclear spins."
Quantum and classical resources in measurement-based quantum computation
Dr Janet Anders, University of Exeter, UK
Abstract
Quantum physics is known to allow the implementation of powerful algorithms [1], however, the precise power increase over classical computation remains open. I will describe an insightful example where the computation relies on the interplay of two components - a restricted classical computer and its interaction with quantum correlated information. It turns out that quantum correlations can enhance the classical computer in such a way that it is able to compute problems beyond its own capability [2]. The example belongs to a type of computation, measurement-based quantum computation, that has no counterpart in classical computing as the computation is driven by quantum measurements rather than gates. Future implementations of this model may require the combination of mobile information carriers that sequentially interact with a stationary register [3] or adiabatic implementations, where the random measurement is replaced by a deterministic evolution [4].
References:
[1]. Anders and Wiesner, Chaos 21, 037102 (2011)
[2]. Anders and Browne, Phys Rev Lett 103, 070502 (2009)
[3]. Kashefi et al, Theoretical Computer Science 430, 51 (2012)
[4]. Antonio et al, arxiv 1309.1443 (2013)
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Dr Janet Anders, University of Exeter, UK
Dr Janet Anders, University of Exeter, UK
Janet Anders is the group leader of the Quantum Non-equilibrium Group at the University of Exeter, UK. With a research focus on quantum information theory and quantum thermodynamics, the group’s work includes an analysis of the non-equilibrium dynamics of nanospheres in optical tweezer experiments, a method that allows the measurement of temperature and temperature gradients at the nanoscale. Previous research includes the characterisation of the temperature of Bose gases and crystals below which thermal entanglement occurs, and contributions to measurement-based quantum computing and quantum cryptography. Janet Anders is a previous Royal Society Dorothy Hodgkin research fellow and chairs the European COST network ‘Thermodynamics in the quantum regime.’
Rapporteur
Professor Tony Hey CBE FREng, Science and Technology Facilities Council, UKRI, UK
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Professor Tony Hey CBE FREng, Science and Technology Facilities Council, UKRI, UK
Professor Tony Hey CBE FREng, Science and Technology Facilities Council, UKRI, UK
Tony Hey began his career as a theoretical physicist with a doctorate in particle physics from the University of Oxford in the UK. After a career in physics that included research positions at Caltech and CERN, and a professorship at the University of Southampton in England, he became interested in parallel computing and moved into computer science. In the 1980s he was one of the pioneers of distributed memory message-passing computing and co-wrote the first draft of the successful MPI message-passing standard.
After being both Head of Department and Dean of Engineering at Southampton, Tony Hey was appointed to lead the UK’s ground-breaking ‘eScience’ initiative in 2001. He recognised the importance of Big Data for science and wrote one of the first papers on the ‘Data Deluge’ in 2003. He joined Microsoft in 2005 as a Vice President and was responsible for Microsoft’s global university research engagements. He worked with Jim Gray and his multidisciplinary eScience research group and edited a tribute to Jim called The Fourth Paradigm: Data-Intensive Scientific Discovery. Hey left Microsoft in 2014 and spent a year as a Senior Data Science Fellow at the eScience Institute at the University of Washington. He returned to the UK in November 2015 and is now Chief Data Scientist at the Science and Technology Facilities Council.
In 1987 Tony Hey was asked by Caltech Nobel physicist Richard Feynman to write up his ‘Lectures on Computation’. This covered such unconventional topics as the thermodynamics of computing as well as an outline for a quantum computer. Feynman’s introduction to the workings of a computer in terms of the actions of a ‘dumb file clerk’ was the inspiration for Tony Hey’s attempt to write The Computing Universe, a popular book about computer science. Tony Hey is a fellow of the AAAS and of the UK's Royal Academy of Engineering. In 2005, he was awarded a CBE by Prince Charles for his ‘services to science.’
Theory and practice of molecular computing with DNA
Dr Damien Woods, Caltech, USA
Abstract
One of the main aims of molecular engineering and computation is to control the structure and dynamics of molecular systems at the nanoscale. We'd like to design systems that are robust to fluctuations in temperature, fluid flow and other uncontrolled factors, yet consist of millions of interacting components. DNA is a versatile and programmable material that meets these criteria. The kinetics and thermodynamics of DNA are reasonably well-understood, and through straightforward Watson-Crick base-pairing interactions we can program this material to create complicated shapes and patterns, as well as to have intricate, even algorithmic, chemical dynamics, all at nanoscale spatial resolution. In this talk, I will give an overview of the state of the art with an emphasis on programability, abilities and limitations of these chemical systems. I will describe how computer science and biology can inspire us about which molecular systems we should try to build next, and how we can use mathematical and algorithmic thinking to give us the tools to control a cacophony of interacting molecules by simply letting them interact in a hands-off self-assembling fashion.
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Dr Damien Woods, Caltech, USA
Dr Damien Woods, Caltech, USA
"Damien Woods is a Senior Postdoctoral Scholar in Computer Science, and The Molecular Programming Fellow, at Caltech, USA. His areas of research include the theory and practice of molecular self-assembly and self-replication, molecular robotics, simulation and intrinsic universality in self-assembly, and the computational complexity of cellular automata, small universal Turing machines, Boolean circuits and optical computers. He uses the theory of computation to understand biological, chemical and physical mechanisms.
Recent work includes developing simulation and intrinsic universality as tools to characterise the computational power of molecular self-assembly systems, and developing a theory of active robotic self-assembly that includes non-local molecular motor movement. Woods has taken to the wet-lab and works on the origin of life with Winfree and Yurke. His PhD explored the computational power of optical computers and, with Naughton, he defined and analyzed physically-inspired optical computing resources. With Murphy he worked on the complexity of Boolean circuits and membranes systems, answering an open question. With Neary he worked on simple models of computation, answering open questions about the time efficiency of small universal Turing machines and the cellular automaton Rule 110, while finding some of the smallest and fastest programs capable of general-purpose computation."