Wednesday, 17 February 2021
Scientists have used cutting-edge research in quantum computation and quantum technology to pioneer a radical new approach to determining how our Universe works at its most fundamental level.
An international team of experts, led by the University of Nottingham, have demonstrated that only quantum and not classical gravity could be used to create a certain informatic ingredient that is needed for quantum computation. Their research “Non-Gaussianity as a signature of a quantum theory of gravity” has been published today in PRX Quantum.
Dr Richard Howl led the research during his time at the University of Nottingham’s School of Mathematics, he said: “For more than a hundred years, physicists have struggled to determine how the two foundational theories of science, quantum theory and general relativity, which respectively describe microscopic and macroscopic phenomena, are unified into a single overarching theory of nature.
During this time, they have come up with two fundamentally contrasting approaches, called ‘quantum gravity’ and ‘classical gravity’. However, a complete lack of experimental evidence means that physicists do not know which approach the overarching theory actually takes, our research provides an experimental approach to solving this.”
This new research, which is a collaboration between experts in quantum computing, quantum gravity, and quantum experiments finds an unexpected connection between the fields of quantum computing and quantum gravity and uses this to propose a way to test experimentally that there is quantum not classical gravity. The suggested experiment would involve cooling billions of atoms in a millimetre-sized spherical trap to extremely low temperatures such that they enter a new phase of matter, called a Bose-Einstein condensate, and start to behave like a single large, quantum atom. A magnetic field is then applied to this “atom” so that it feels only its own gravitational pull. With this all in place, if the single gravitating atom demonstrates the key ingredient needed for quantum computation, which is curiously associated with “negative probability”, nature must take the quantum gravity approach.
This proposed experiment uses current technology, involves just a single quantum system, the gravitating “atom”, and does not rely on assumptions concerning the locality of the interaction, making it simpler than previous approaches and potentially expediating the delivery of the first experimental test of quantum gravity. Physicists would then, after more than a hundred years of research, finally have information on the true overarching, fundamental theory of nature.
Dr Marios Christodoulou, from the University of Hong Kong who was part of the collaboration, added: “This research is particularly exciting as the experiment proposed would also connect with the more philosophical idea that the universe is behaving as an immense quantum computer that is calculating itself, by demonstrating that quantum fluctuations of spacetime are a vast natural resource for quantum computation.”
The research brought together experimental and theoretical physicists from a range of disciplines and international research institutions. The other authors are: Richard Howl, Vlatko Vedral (Oxford and Singapore), Devang Naik (CNRS, Bordeaux), Marios Christodoulou (Hong Kong and Oxford), Carlo Rovelli (Marseille) and Aditya Iyer (Oxford).
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More information is available from Dr Richard Howl on rjhowl@googlemail.com or Jane Icke, Media Relations Manager for the Faculty of Science at the University of Nottingham, on +44 (0)115 951 5751, jane.icke@nottingham.ac.uk
Notes to editors:
About the University of Nottingham
Ranked 32 in Europe and 16th in the UK by the QS World University Rankings: Europe 2024, the University of Nottingham is a founding member of the Russell Group of research-intensive universities. Studying at the University of Nottingham is a life-changing experience, and we pride ourselves on unlocking the potential of our students. We have a pioneering spirit, expressed in the vision of our founder Sir Jesse Boot, which has seen us lead the way in establishing campuses in China and Malaysia - part of a globally connected network of education, research and industrial engagement.
Nottingham was crowned Sports University of the Year by The Times and Sunday Times Good University Guide 2024 – the third time it has been given the honour since 2018 – and by the Daily Mail University Guide 2024.
The university is among the best universities in the UK for the strength of our research, positioned seventh for research power in the UK according to REF 2021. The birthplace of discoveries such as MRI and ibuprofen, our innovations transform lives and tackle global problems such as sustainable food supplies, ending modern slavery, developing greener transport, and reducing reliance on fossil fuels.
The university is a major employer and industry partner - locally and globally - and our graduates are the second most targeted by the UK's top employers, according to The Graduate Market in 2022 report by High Fliers Research.
We lead the Universities for Nottingham initiative, in partnership with Nottingham Trent University, a pioneering collaboration between the city’s two world-class institutions to improve levels of prosperity, opportunity, sustainability, health and wellbeing for residents in the city and region we are proud to call home.
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