Time evolution of fermionic systems from first principles

Lead Research Organisation: University of Surrey
Department Name: Physics

Abstract

Nuclei are minute objects at the center of atoms, formed by several neutrons and protons, bound together by the strong interaction. Elements are defined according to their number of protons, while different isotopes of an element are specified by their number of neutrons. Some combinations of neutrons and protons yield isotopes which are stabler than others. Of the around 3000 isotopes observed so far, only about 280 of them are stable. The rest, unstable (radioactive) nuclei, decay with a characteristic time that shortens significantly as the proton and neutron content of a nucleus moves away from the stable conditions. Several unstable isotopes have actually not been measured yet: some models predict that about 3000 more of them might actually exist. So what does this have to do with us? Even though you might think that such uncommon nuclei have little impact on our world, it turns out that they play a basic role. Exotic isotopes are formed continuously in stars and they are the seeds from which all the remaining nuclei, including the stable ones, are formed. Ultimately, isotope science teaches us about the stuff we are made of. The 2010s are going to be a particularly exciting decade for nuclear physics. Extremely unstable atomic nuclei will be created soon in research laboratories that are being built in France, Germany, Japan or the US as part of a coordinated worldwide effort to reach the limits of nuclear stability. With the valuable experimental data collected in these facilities, theorists like me will be able to understand better how nuclei behave. This is a very challenging task, because quantum physics is involved and everyday intuition often fails when applied to nuclei. As a matter of fact, experience shows that extrapolating from trends of known isotopes is not enough to understand the unfamiliar phenomena occurring in exotic nuclei. Nuclear physics is thus facing an unknown territory, an uncharted area of the isotope chart. As in every exploration, the most advanced technology is required to proceed securely through untraveled lands. For nuclear physics, theoretical models to describe reaction with exotic isotopes need critical improvements. A key issue is predictability: present models are generally based on a series of parameters which are typically derived from stable nuclei. Extending these models to exotic isotopes can introduce uncontrolled errors and undermine the predictive power of theoretical models. An alternative is to try to start from as few ingredients and parameters as possible: only basic constituents (neutrons and protons), the interaction between them and a quantum many-body theory to account for the presence of all the particles in the system. My research proposal is aimed in this direction. Using a quantum mechanical time-dependent approach, I would like to simulate collisions of nuclei directly in the computer, by solving a set of equations that simultaneously describe the structural properties of the isotopes as well as their evolution in time. The non-equilibrium Green's functions techniques that I would like to work on are currently being developed to study other systems (nanodevices, molecules, plasmas), but their broad number of potential applications make them perfect candidates for the description of nuclear collisions. The power of physics lies in its ability to describe very different systems with the same tools. Quantum mechanical time-evolving algorithms, however, are rather challenging from the computational point of view. I will need to develop new numerical techniques and use powerful computers to carry the project on successfully. A particularly curious issue related to Green's functions techniques is that they introduce the so-called memory effects. What this means, in practice, is that the simulated elements need to remember their past in order to project their future: just as we humans should do from time to time!

Publications

10 25 50
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Carbone A (2011) Latent heat of nuclear matter in Physical Review C

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Rios A (2011) Liquid-gas phase transition in nuclear matter in the mean-field approximation in Journal of Physics: Conference Series

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Vidaña I (2012) Symmetry energy within the BHF approach in Journal of Physics: Conference Series

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Carbone A (2012) High-momentum components in the nuclear symmetry energy in EPL (Europhysics Letters)

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Goddard PM (2013) Charge radius isotope shift across the N=126 shell gap. in Physical review letters

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Goddard P (2013) Dipole response of 76 Se above 4 MeV in Physical Review C

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Carbone A (2014) Tensor force effects and high-momentum components in the nuclear symmetry energy in The European Physical Journal A

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Sellahewa R (2014) Isovector properties of the Gogny interaction in Physical Review C

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Somà V (2014) Nucleon mean-free path in the medium in EPJ Web of Conferences

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Goddard P (2014) Cause of the charge radius isotope shift at the N =126 shell gap in EPJ Web of Conferences

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Rios A (2015) Covariance analysis of finite temperature density functional theory: symmetric nuclear matter in Journal of Physics G: Nuclear and Particle Physics

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Reifarth R (2016) Nuclear astrophysics with radioactive ions at FAIR in Journal of Physics: Conference Series

 
Description ECT* Workshop Organization Grant - Advances in time-dependent methods for quantum many-body systems 14-18 October 2013
Amount € 8,000 (EUR)
Organisation European Center for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) 
Sector Public
Country Italy
Start 10/2013 
End 11/2013
 
Description ECT* Workshop Organization Grant - Observations and theory in the dynamics of neutron stars 26-30 January 2015
Amount € 5,000 (EUR)
Organisation European Center for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) 
Sector Public
Country Italy
Start 01/2015 
End 02/2015
 
Description Equipment for Theoretical and Experimental Nuclear Physics
Amount £33,275 (GBP)
Funding ID ST/N002636/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 10/2015 
End 03/2016
 
Description NewCompStar Workshop Organization Grant - Observations and theory in the dynamics of neutron stars 26-30 January 2015
Amount € 6,000 (EUR)
Organisation European Cooperation in Science and Technology (COST) 
Sector Public
Country European Union (EU)
Start 01/2015 
End 02/2015
 
Description Nuclear Structure and Reactions: Equipment for Theory and Experiment
Amount £44,219 (GBP)
Funding ID ST/J000051/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 01/2014 
End 03/2014
 
Description Nuclear Structure and Reactions: Theory and Experiment
Amount £1,836,570 (GBP)
Funding ID ST/L005743/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 08/2014 
End 09/2018
 
Description Nuclear Structure and Reactions: Theory and Experiment
Amount £2,194,320 (GBP)
Funding ID ST/J000051/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 08/2011 
End 07/2015
 
Description STFC Consolidated Grant
Amount £2,543,478 (GBP)
Funding ID ST/P005314/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 10/2017 
End 09/2021
 
Description Santander Bank Staff Travel Scheme
Amount £1,600 (GBP)
Organisation Santander Bank 
Sector Private
Country United States
Start 11/2013 
End 12/2013
 
Description Surrey Institute of Advanced Studies Workshop Organization Grant - "Neutron stars" 29-30 July 2013
Amount £4,000 (GBP)
Organisation University of Surrey 
Department Institute of Advanced Studies
Sector Academic/University
Country United Kingdom
Start 07/2013 
End 08/2013
 
Description Michigan State University, Prof. P. Danielewicz 
Organisation Michigan State University
Department National Superconducting Cyclotron Laboratory
Country United States 
Sector Academic/University 
PI Contribution Development of time-dependent techniques
Collaborator Contribution Development of time-dependent techniques
Impact One paper being prepared
Start Year 2009
 
Description TU Darmstadt, A. Carbone 
Organisation Technical University of Darmstadt
Country Germany 
Sector Academic/University 
PI Contribution A. Carbone was my PhD student and is now a postdoc at TU Darmstadt, where she carries on with PhD-related research topics.
Collaborator Contribution A. Carbone was my PhD student and is now a postdoc at TU Darmstadt, where she carries on with PhD-related research topics.
Impact Published articles in field journals (see publications list)
Start Year 2014
 
Description Universidad de Chile 
Organisation University of Chile
Department Department of Physics
Country Chile 
Sector Academic/University 
PI Contribution Work on Brueckner-Hartree-Fock theory to describe dineutron states in neutron matter.
Collaborator Contribution Work on Brueckner-Hartree-Fock theory to describe dineutron states in neutron matter.
Impact http://arxiv.org/abs/1602.05234
Start Year 2013
 
Description University of Barcelona, Prof. Arturo Polls 
Organisation University of Barcelona
Country Spain 
Sector Academic/University 
PI Contribution Training of a PhD student there
Collaborator Contribution Training of PhD candidate Arianna Carbone
Impact Papers and PhD thesis
Start Year 2009
 
Description University of Milano, X. Roca-Maza 
Organisation National Institute for Nuclear Physics
Department National Institute for Nuclear Physics - Milano
Country Italy 
Sector Public 
PI Contribution Started research project on error propagation in nuclear EDF
Collaborator Contribution Started research project on error propagation in nuclear EDF
Impact Proceedings submitted. More papers to come.
Start Year 2014
 
Description Washington University of St Louis, Prof. W. H. Dickhoff 
Organisation Washington University in St Louis
Country United States 
Sector Academic/University 
PI Contribution Calculations of SCGF in inifinite matter
Collaborator Contribution Pairing calculations using input provided by Surrey
Impact Paper to be submitted. Previous work already submitted.
Start Year 2009
 
Description Daresbury workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Type Of Presentation Workshop Facilitator
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact 20 researchers attended the meeting.

Papers and collaboration started.
Year(s) Of Engagement Activity 2013
URL http://personal.ph.surrey.ac.uk/~m01088/IoP_correlations/
 
Description ISNET workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Type Of Presentation Workshop Facilitator
Geographic Reach International
Primary Audience Other audiences
Results and Impact 19-20 August 2013

Collaboration papers and topical journal edition.
Year(s) Of Engagement Activity 2013
URL http://indico.cern.ch/event/253381/
 
Description IoP Talk (South Central Branch, Guildford) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Paper Presentation
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Outreach of neutron star physics to wide audience.
Year(s) Of Engagement Activity 2013
 
Description Neutron Star Workshop, July 2013 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Type Of Presentation Workshop Facilitator
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact 60 participants in a research workshop.

Papers published.
Year(s) Of Engagement Activity 2013
URL http://personal.ph.surrey.ac.uk/~m01088/IAS/
 
Description Observations and Theory in the dynamics of neutron stars - Research Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Research workshop at European Center for Theoretical Studies on Nuclear Physics. I was one of the co-organisers, and presented my own research results. Discussions sparked a variety of publications in the neutron star community.
Year(s) Of Engagement Activity 2015
URL https://sites.google.com/site/ectworkshopns2015/
 
Description School Research Talk (Reed's School) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact 60 pupils attended a talk on "Neutron Stars" as part of their annual "Science Talk" at Reed's Independent School (Cobham, Surrey). Questions and discussion after the talk.
Year(s) Of Engagement Activity 2016
 
Description TEDx Surrey Event "Redefining the ordinary" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Talk given at TEDx event at Surrey. YouTube video of talk has been viewed 2000+ times.
Year(s) Of Engagement Activity 2016
URL https://www.youtube.com/watch?v=F1Kml3zuTco&feature=youtu.be&list=PLe0_9oxbi_ScqzzqDgsi16g6vMSmJiL2T
 
Description Time-dependent methods Workshop (ECT*) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation workshop facilitator
Geographic Reach International
Primary Audience Other audiences
Results and Impact 40 researchers attended a meeting on time-dependent methods in nuclear physics and related areas.

Various research papers.
Year(s) Of Engagement Activity 2013
URL http://personal.ph.surrey.ac.uk/~m01088/ECT/ECT_Workshop/Workshop.html
 
Description University of Surrey outreach event, Why do gravitational waves matter 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact General talk (as a part of 4 physics talks) on impact of the gravitational wave discovery announced on February 2016. Lecture to general audience from the Guildford area.
Year(s) Of Engagement Activity 2016