Simulation-based Inference of gravitational waves signals from black holes and neutron stars

Black holes and neutron stars are the densest objects in the universe, well beyond what we can produce in a laboratory and at the very edge of our understanding of physics. They lead to puzzling physical consequences, in particular regarding the behaviour of space and time. When they collide, they produce the most violent events in the universe, shaking space and time and creating gravitational waves: ripples in the fabric of spacetime which propagate away at the speed of light. Gravitational-waves were observed for the very first time in September 2015, when two colliding black holes were detected by the LIGO-Virgo collaboration. Since then, several signals have been observed, and we were able to characterise the black holes and neutron stars at the source of those gravitational waves.

This characterisation currently involves stochastic sampling methods with a very high computational cost, and simplified assumptions of the detectors’ properties. This project will leverage modern advances in likelihood-free inference methods, and in particular simulation-based inference, to solve this inference problem accurately. Our approach will adapt automatically to changing features in the detector noise, allow for new new data to be continuously included, and will be applicable to the upcoming new generation of gravitational-wave detectors.

Gravitational-wave sources are laboratories where we can measure in neutron stars the equation of state of matter at densities otherwise unattainable, and test General Relativity in the strong field regime. Inference of their extragalactic population enables new understandings of the Universe’s structure of matter, and independent measurements of the Universe’s expansion.

 For more information, or if there are any questions, please contact Dr Vivien Raymond RaymondV@cardiff.ac.uk

The typical academic requirement is a minimum of a 2:1 physics and astronomy or a relevant discipline. 

Applicants whose first language is not English are normally expected to meet the minimum University requirements (e.g. IELTS 6.5 Overall with 5.5 minimum in sub-scores) (https://www.cardiff.ac.uk/study/international/english-language-requirements) 

How to apply 

Applicants should apply to the Doctor of Philosophy in Physics and Astronomy. 

Applicants should submit an application for postgraduate study via the Cardiff University webpages (https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/physics-and-astronomy) including: 

• your academic CV 

• Your degree certificates and transcripts to date including certified translations if these are not in English 

• a personal statement/covering letter 

• two references, at least one of which should be academic. Your references can be emailed by the referee to physics-admissions@cardiff.ac.uk  

Please note: We are do not contact referees directly for references for each applicant due to the volume of applications we receive.     

In the "Research Proposal" section of your application, please specify the project title and supervisors of this project.

In the funding section, please select that you will be self-funded or include your own sponsorship or scholarship details.

Once your application is submitted, we will review it and advise you within a few weeks if you have been shortlisted for an interview.