Workshop on String Inflation After Planck
Lead Research Organisation:
University of Liverpool
Department Name: Mathematical Sciences
Abstract
Cosmological inflation is an epoch of extremely rapid expansion of the Universe, in the first tiny fraction of a second after the Universe began. Inflation is remarkably consistent with cosmological observations, however, it lacks a convincing theoretical explanation. In particular, occurring at very early times, when the Universe was very small and energetic, inflation turns out to be very sensitive to the effects of quantum gravity. There has therefore been a large body of work trying to realise cosmological inflation from string theory, which is the leading candidate for a theory of quantum gravity.
Attempts to realise inflation from string theory lead to several fundamental and mathematical questions. String theory has not only the four spacetime dimensions that we observe today in the Universe, but six extra dimensions. These extra dimensions have to be compactified in a very special way -- yet to be fully understood -- in order for inflation to occur in our four dimensional spacetime. Compactification leads to a number of new degrees of freedom, called moduli, which must somehow be decoupled during inflation. This is known as the moduli stabilisation problem, and calls for a number of stringy ingredients -- rich in mathematics -- like instantons. Moreover, although string theory also requires a special symmetry known as supersymmetry, during inflation supersymmetry has to be hidden in some way. A complete mathematical description of this hidden supersymmetry is currently in development.
The purpose of this workshop is to bring together international experts working on these topics in a friendly environment with plenty of time for discussion and collaboration. New collaborations and projects will be initiated, addressing the above and other important questions in the light of the latest cosmological observations, e.g. from the Planck satellite. This research will connect the theoretical and mathematical foundations of quantum gravity to observations in the sky.
Attempts to realise inflation from string theory lead to several fundamental and mathematical questions. String theory has not only the four spacetime dimensions that we observe today in the Universe, but six extra dimensions. These extra dimensions have to be compactified in a very special way -- yet to be fully understood -- in order for inflation to occur in our four dimensional spacetime. Compactification leads to a number of new degrees of freedom, called moduli, which must somehow be decoupled during inflation. This is known as the moduli stabilisation problem, and calls for a number of stringy ingredients -- rich in mathematics -- like instantons. Moreover, although string theory also requires a special symmetry known as supersymmetry, during inflation supersymmetry has to be hidden in some way. A complete mathematical description of this hidden supersymmetry is currently in development.
The purpose of this workshop is to bring together international experts working on these topics in a friendly environment with plenty of time for discussion and collaboration. New collaborations and projects will be initiated, addressing the above and other important questions in the light of the latest cosmological observations, e.g. from the Planck satellite. This research will connect the theoretical and mathematical foundations of quantum gravity to observations in the sky.
Planned Impact
String cosmology is a new and exciting field of research, in which string theorists can help cosmologists interpret their data, and cosmologists can help string theorists develop, test and constrain models of Nature.
String Inflation and the Planck Satellite provide an outstanding example of this symbiotic relationship. Inflation indeed potentially provides the much needed link between string theory and observations. On one hand, models of inflation from string theory can leave characteristic patterns in the CMB, which cosmologists can search for. On the other hand, data from cosmological observations can stimulate new developments in string theory, rule out certain models of string inflation, and prefer others.
The Planck Satellite is funded by the European Space Agency, and UK scientists and engineers played a major role in its design, construction, operation and data analysis. UK theorists are also leaders in the field of string cosmology, with several internationally reputable groups (including the organisers). The workshop will strengthen this position, and provide an opportunity for UK scientists, including young researchers, to disseminate new results and build new international collaborations.
Moreover, the workshop will lead to developments that will direct future experiments and observations in cosmology, in which the UK will continue to play a leading role. The workshop will also lead to more formal developments in the mathematical and theoretical foundations of string theory, e.g. in our understanding of non-supersymmetric string compactifications and the non-perturbative ingredients of string theory, likely opening the way to new mathematics.
More generally, the research that will be explored during the workshop addresses fundamental questions which every human being ponders upon in some way - what was the origin of our Universe, and what was it like in its first moments of existence? Participants in the meeting will help disseminate this research to the wider public in their respective outreach activities, which are also instrumental in drawing more people and young people into science and engineering.
String Inflation and the Planck Satellite provide an outstanding example of this symbiotic relationship. Inflation indeed potentially provides the much needed link between string theory and observations. On one hand, models of inflation from string theory can leave characteristic patterns in the CMB, which cosmologists can search for. On the other hand, data from cosmological observations can stimulate new developments in string theory, rule out certain models of string inflation, and prefer others.
The Planck Satellite is funded by the European Space Agency, and UK scientists and engineers played a major role in its design, construction, operation and data analysis. UK theorists are also leaders in the field of string cosmology, with several internationally reputable groups (including the organisers). The workshop will strengthen this position, and provide an opportunity for UK scientists, including young researchers, to disseminate new results and build new international collaborations.
Moreover, the workshop will lead to developments that will direct future experiments and observations in cosmology, in which the UK will continue to play a leading role. The workshop will also lead to more formal developments in the mathematical and theoretical foundations of string theory, e.g. in our understanding of non-supersymmetric string compactifications and the non-perturbative ingredients of string theory, likely opening the way to new mathematics.
More generally, the research that will be explored during the workshop addresses fundamental questions which every human being ponders upon in some way - what was the origin of our Universe, and what was it like in its first moments of existence? Participants in the meeting will help disseminate this research to the wider public in their respective outreach activities, which are also instrumental in drawing more people and young people into science and engineering.
People |
ORCID iD |
| Susha Parameswaran (Principal Investigator) |
| Description | The workshop String Inflation After Planck attracted around 50 participants from across the world, including leading institutions in Europe, North America, South America and Asia, and world experts across disciplines in observational cosmology, theoretical cosmology, string theory and mathematical physics. The meeting began with two review talks from observationalists, with Steve Gratton (University of Cambridge and the Planck Collaboration) presenting the latest results from Planck and Carlo Contaldi (Imperial College) presenting the current state-of-the art in gravitational wave searches in CMB experiments and plans for the next generation of surveys. Theorists included Andrei Linde (Stanford University) and Nemanja Kaloper (UC Davies) discussing their recent work on models of inflation, dark energy and supersymmetry breaking. Progress in relevant mathematical physics was presented by Renata Kallosh (Stanford University), Liam McAllister (Cornell) and Alexander Westphal (DESY Hamburg), discussing some of the lastest mathematical structures that are being developed to describe string inflationary models (non-linear supersymmetry, random matrix theory, monodromy). Younger participants were also given an opportunity to present their work. There was much discussion both during the talks and over coffee breaks, lunches and informal discussion sessions. This included discussions across disciplines, where mathematical physicists, theorists and experimentalists could inform each other of the latest developments and challenges, and within disciplines, where contraversies and challenges in the fields could be addressed and new collaborations initiated. Particularly fruitful were mirrored talks creating a direct dialogue across disciplines (e.g. theorist Krippendorf "The String Soundscape at Gravitational Wave Detectors" and observationalist Contaldi "Prospects for Gravitational Wave Background Measurements"; mathematical physics talk from Marsh "Manyfield inflation" and Westphal on Random Matrix Theory and string cosmologist Achucarro "Multifield inflation with ultra-light fields, revisited"; and mathematical physics talk from McAllister "Backreaction of Axion Monodromy Charge" and theoretical cosmologist Kaloper "A monodromy from London"). The meeting was considered a great success by all participants, and it was agreed that it would be invaluable to have another workshop of a similar nature in the near future. Subsequently, the workshop "Post-Inflationary String Cosmology" is being organised in Bologna for September 2017. |
| Exploitation Route | The workshop's interdisciplinary nature led to significant impact across fields. Experimentalists learnt about the current theoretical challenges in realising inflation from string theory and about novel experimental signatures that might be searched for. This will help direct research in observational cosmology, which directly connects with technology and engineering. Similarly valuable were the updates on the cosmological data provided to theorists by the Planck collaboration and gravitational wave experiments, in particular various hints of tensions in the data and prospects for future sensitivities. This will guide theorists in their efforts to connect to data. Interactions between mathematical physics and theoretical physics were also synergetic, where theorists will put to use new mathematical structures and mathematical physicists have understood where new mathematical frameworks are needed. Beyond academia, research in early Universe cosmology and fundamental particle physics captures the imagination of the public and draws talented school pupils into science and technology. Many of the workshop participants are involved in communicating this science to the general public in a wide variety of outreach activities. |
| Sectors | Education,Other |
| URL | https://sites.google.com/site/stringinflationafterplanck/home |
| Description | The research explored during the workshop addresses fundamental questions which every human being ponders upon in some way - what was the origin of our Universe, and what was it like in its first moments of existence? Participants in the meeting are helping to disseminate this research to the wider public in their respective outreach activities, which are also instrumental in drawing more people and young people into science and engineering. Moreover, in the long term, the theoretical research discussed during the workshop directs future experiments and observations in cosmology, which in turn directly drive developments in technology and engineering. The mathematical physics discussed during the workshop will also open the way to new mathematics. |
| First Year Of Impact | 2016 |
| Sector | Education,Other |
| Impact Types | Cultural,Societal |
| Description | Conference and Short Course grant |
| Amount | £2,000 (GBP) |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 09/2016 |
| End | 09/2016 |
| Description | Workshop grant |
| Amount | £2,000 (GBP) |
| Organisation | Durham University |
| Department | Institute for Particle Physics Phenomenology (IPPP) |
| Sector | Academic/University |
| Country | United Kingdom |
| Start | 09/2016 |
| End | 09/2016 |
| Description | Workshop grant |
| Amount | € 1,000 (EUR) |
| Organisation | National Institute for Nuclear Physics |
| Sector | Academic/University |
| Country | Italy |
| Start | 09/2017 |
| End | 09/2017 |
| Description | Workshop grant |
| Amount | € 4,000 (EUR) |
| Organisation | National Institute for Nuclear Physics |
| Sector | Academic/University |
| Country | Italy |
| Start | 09/2017 |
| End | 09/2017 |
| Description | Organising Committee for Workshop on Post-Inflationary String Cosmology, Bologna, 18-21 September 2017 |
| Organisation | University of Bologna |
| Country | Italy |
| Sector | Academic/University |
| PI Contribution | The workshop Post-Inflationary String Cosmology, held in Bologna 18-21 September 2017, was initiated by myself, as a continuation of the current Workshop on String Inflation After Planck. I was one of the main organisers. |
| Collaborator Contribution | The workshop was organised jointly by myself and my partners in Bologna, where the main local organiser is Michele Cicoli. |
| Impact | The workshop was inter-disciplinary, with participants from string theory, theoretical cosmology and theoretical astroparticle physics. |
| Start Year | 2017 |