TESTING THE FOUNDATIONS OF COSMOLOGY

Lead Research Organisation: King's College London
Department Name: Physics

Abstract

The past three years have been an exciting time for observational and experimental cosmology, highlighted by the release of the Planck Surveyor data and the discovery of the Higgs at the Large Hadron Collider. In addition to these flagship experiments, other experiments such as B-mode experiments BICEP2 and ACT, large galaxy surveys such as BOSS and the Dark Energy Survey (DES) and the many direct detection Dark Matter experiments are rapidly converging to a Standard Model of Cosmology described by a few parameters such as the amount of Dark Matter or Dark Energy in the universe. Yet in the wake of the release of these high quality data, our understanding of the fundamental building blocks of cosmology seems as distant as ever. We do not understand what is the origin of the Standard Model of Cosmology: What is the nature of Dark Matter and Dark Energy? How and why did the Big Bang begin? What are the progenitors of the super massive black holes in the centres of galaxies? Will we see signatures of quantum gravity? Can we see cosmic (super-)strings in the Universe? What is there more matter than anti-matter?

The answers to these questions will form the foundations of our future understanding of cosmology.

In this scientific programme proposed here by the members of the Theoretical Particle Physics and Cosmology (TPPC) Group in the Physics Department of King's College London, we will directly address these questions by exploring the fundamental physics that underlie these foundations and test them with observational predictions. Our efforts center around three main projects.

1. Strong Gravity in Cosmology: How did the Big Bang begin? What is the nature of the super massive black holes in centres of galaxies? Can we see cosmic super strings in the sky? The reason the answers to these questions remain unknown is because they require us to solve Einstein's theory of gravity in its full, most complicated form. We will use modern numerical methods and state-of-the-art computer systems to find them.

2. The physics of the Cerenkov Telescope Array (CTA): The United Kingdom is a major partner in the international collaborative efforts to construct the next generation telescope to explore the universe in its most energetic form using gamma rays. KCL is a partner of this effort, and we will use the telescope to study the physics of Dark Matter and test our most fundamental theories such as Special Relativity.

3. Fundamental Physics with Gravitational Waves: Gravitational waves are a prediction of Einstein's theory of gravity. We will investigate their nature by studying their properties to understand the nature of gravity, and use them to illuminate the universe.

Planned Impact

Many aspects of our proposal involve cutting-edge high-performance computing - for example, we are one of the first users of the new Many-Integrated-Core (MIC) chip architecture that is expected to lead the way towards Exaflop supercomputing, and part of our research in developing efficient parallel architectures within the MIC infrastructure is expected to flow directly to industry. The COSMOS consortium, of whom investigator Eugene Lim is an executive member, has a close partnership with Intel, the developers of the MIC chips. In particular, we intend to release GRCHOMBO publicly with a GNU License in 2016 - this will benefit researchers internationally, and raise the profile of UK cosmology.

Part of our research in developing efficient parallel architectures within the MIC infrastructure is expected flow directly to industry. In addition, the research at King's provide an effective and rigorous environment for the scientific training of young researchers in the ability to solve hard and complex problems. The TPPC Group at King's has trained many younger researchers who have later entered the financial and other sectors of the economy, providing the society with a cohort of highly trained and motivated workforce. For example, investigator Malcolm Fairbairn have recently won funding for a Trainor Fellowship which provide funding for a PhD student specializing in use of machine learning in cosmology in partnership with Tractable, an industry partner.

Moreover, cutting-edge theoretical physics attracts young intellectual talent from both within and outside the UK. A substantial fraction of these take non-academic jobs in the UK, thus providing the economy with highly-trained people who are competitive at a global level. Such spin-offs from fundamental science have long been vital to the international economic and industrial competitiveness that the UK seeks. A crucial feature of the modern UK's economic and social wealth is its international reputation as a world leader for independent thinking in both the academic and industrial sectors.

Investigator Malcolm Fairbairn has given many radio and TV interviews, and has been quoted in national newspapers such as the Guardian for his work on Dark Matter. He is also a frequent speaker in many outreach lectures to the general public. Investigator Eugene Lim has given outreach lectures to the general public, and has written articles for both online and print science magazines (such as New Scientist). Furthermore, both investigators are active in outreach to schools, giving lectures to schools and organizing the KCL Physics Evening Lectures series which are well attended by A-level students. Investigator Mairi Sakellariadou has been actively involved with Minerva Scientifica, an evolving music-theatre programme reflecting the lives of British Women Scientists told through the music of British Women Composers, and is a frequent guests on scientific panel discussions.

Publications

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Aurrekoetxea Josu C. (2019) The Effects of Potential Shape on Inhomogenous Inflation in arXiv e-prints

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Aurrekoetxea Josu C. (2020) Coherent Gravitational Waveforms and Memory from Cosmic String Loops in arXiv e-prints

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Clough K (2018) Robustness of Inflation to Large Tensor Perturbations in Journal of Cosmology and Astroparticle Physics

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Golat S (2020) Evanescent gravitational waves in Physical Review D

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Golat Sebastian (2019) Evanescent Gravitational Waves in arXiv e-prints

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Helfer T (2019) Cosmic string loop collapse in full general relativity in Physical Review D

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Helfer Thomas (2018) Cosmic String Loop Collapse in Full General Relativity in arXiv e-prints

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Shandera Sarah (2019) Probing the origin of our Universe through cosmic microwave background constraints on gravitational waves in Bulletin of the American Astronomical Society

 
Description We have released GRCHOMBO to the public domain through the BSD-3 License. This is one of the goals of the grant.
Exploitation Route This code had been investigated by other research groups who might adopt it.
Sectors Other

URL http://www.grchombo.org
 
Description FQXi Large Grant Round 2016
Amount $121,462 (USD)
Organisation Foundational Questions Institute (FQXi) 
Sector Charity/Non Profit
Country United States
Start  
 
Description COSMOS Consortium 
Organisation STFC DiRAC COSMOS Shared Memory Service (HPC Facility Cambridge)
Country United Kingdom 
Sector Academic/University 
PI Contribution I am board member of the COSMOS consortium. In addition to HPC concerns, we are also collaborating on the public release and development of the numerical code GRCHOMBO of which I am a primary developer and founder.
Collaborator Contribution Provide computing resources. Technical and development work on GRCHOMBO.
Impact Several scientific papers written with the use of the facility, and with technical assistance from the consortium members. Organized a conference on numerical cosmology. Technical and development work on GRCHOMBO.
Start Year 2010
 
Description GRCHOMBO Code Collaboration 
Organisation Argonne National Laboratory
Country United States 
Sector Public 
PI Contribution I am one of the three co-founders of the GRCHOMBO code collaboration. The code is a state of the art numerical relativity code that is publicly available. My research group is very active in maintaining and contributing to the code.
Collaborator Contribution They contribute to the development of the code.
Impact GRCHOMBO, a multi-purpose numerical relativity code, is now open sourced and available.
Start Year 2011
 
Description GRCHOMBO Code Collaboration 
Organisation Intel Corporation
Country United States 
Sector Private 
PI Contribution I am one of the three co-founders of the GRCHOMBO code collaboration. The code is a state of the art numerical relativity code that is publicly available. My research group is very active in maintaining and contributing to the code.
Collaborator Contribution They contribute to the development of the code.
Impact GRCHOMBO, a multi-purpose numerical relativity code, is now open sourced and available.
Start Year 2011
 
Description GRCHOMBO Code Collaboration 
Organisation Queen Mary University of London
Country United Kingdom 
Sector Academic/University 
PI Contribution I am one of the three co-founders of the GRCHOMBO code collaboration. The code is a state of the art numerical relativity code that is publicly available. My research group is very active in maintaining and contributing to the code.
Collaborator Contribution They contribute to the development of the code.
Impact GRCHOMBO, a multi-purpose numerical relativity code, is now open sourced and available.
Start Year 2011
 
Description GRCHOMBO Code Collaboration 
Organisation University of Cambridge
Country United Kingdom 
Sector Academic/University 
PI Contribution I am one of the three co-founders of the GRCHOMBO code collaboration. The code is a state of the art numerical relativity code that is publicly available. My research group is very active in maintaining and contributing to the code.
Collaborator Contribution They contribute to the development of the code.
Impact GRCHOMBO, a multi-purpose numerical relativity code, is now open sourced and available.
Start Year 2011
 
Description GRCHOMBO Code Collaboration 
Organisation University of Oxford
Country United Kingdom 
Sector Academic/University 
PI Contribution I am one of the three co-founders of the GRCHOMBO code collaboration. The code is a state of the art numerical relativity code that is publicly available. My research group is very active in maintaining and contributing to the code.
Collaborator Contribution They contribute to the development of the code.
Impact GRCHOMBO, a multi-purpose numerical relativity code, is now open sourced and available.
Start Year 2011
 
Title GRChombo Numerical Relativity Code 
Description Full Adaptive Mesh Refinement capable Numerical Relativity code. 
Type Of Technology Software 
Year Produced 2018 
Open Source License? Yes  
Impact Code is now in production phase with science output forthcoming by the beginning of 2015. Code is released under BSD-3 License in 2018. 
URL http://www.grchombo.org
 
Description Article in a popular book "Why the Universe Exists: How particle physics unlocks the secrets of everything" 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact I contributed an article for a popular science book "Why the Universe Exists: How particle physics unlocks the secrets of everything".
Year(s) Of Engagement Activity 2017
URL https://www.amazon.co.uk/Why-Universe-Exists-everything-Scientist-ebook/dp/B01M3TVHCU/ref=la_B001JRU...
 
Description Interviewed by BBC4 as part of Science Program 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I was filmed by BBC4 as part of a science special hosted by Prof Jim Al-Khalili.
Year(s) Of Engagement Activity 2016
 
Description Interviewed on Radio by US based National Public Radio 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I was interviewed on live radio (US National Public Radio) on the Colin McEnroe show.
Year(s) Of Engagement Activity 2016
URL http://wnpr.org/post/multiplicity-multiverse
 
Description New Scientist Expert Live! 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Media (as a channel to the public)
Results and Impact This is a public event organized by a national media company (New Scientist). I am a speaker and a panelist at this event.
Year(s) Of Engagement Activity 2018