### Here you will find any information about current job vacancies at the Centre for Theoretical Cosmology. We may also, from time to time, post details of relevant positions within other groups or centres at DAMTP.

## Applications are invited for the following PhD projects

*Project 1: Fundamental Physics from Gravitational Lensing of the CMB*

The Cosmic Microwave Background, radiation left over from the infant universe, is gravitationally lensed along its path to us. This lensing signal contains a wealth of information about the physics of the early universe, the properties of neutrinos and dark energy, and the large-scale distribution of dark matter. The study of CMB lensing at high precision is therefore crucial for the success of future CMB cosmology. We have an opening for a PhD student to play a leading role in this exciting new field, which lies at the interface of theoretical and observational cosmology. The PhD research can span both novel theoretical development and innovative, computationally intensive data analysis for AdvancedACT and Simons Observatory (ground-based CMB experiments with Cambridge participation). Possible projects include: work on theoretical techniques and computational tools for lensing removal in order to reveal signals from inflation and the early universe, new measurements of lensing maps that will help determine the unknown neutrino mass scale, and comparisons of CMB lensing and large scale structure to better probe dark energy. There will be extensive opportunities for collaboration with researchers both in Cambridge and at leading US institutions.

*Project 2: Investigating Methods for Optimal estimation of correlation functions on incomplete domains.*

In analyzing cosmological data sets we generally transform to harmonic space then form correlation functions. In practice this is complicated by the fact that the data does not cover the full domain, either due to experimental constraints foreground contamination, so harmonics are no longer orthogonal. This leads to mode coupling which translates into increased error bars on cosmological observables. Recently we discovered a novel approach, called inpainting, that significantly reduced this coupling allowing for almost optimal estimation of CMB power spectrum. The goal of this project would be to take this method and apply it to Planck CMB data producing new parameter constraints and then generalize them to other data sets like galaxy surveys.

*Project 3: Halo clustering and galaxy surveys*

Current and upcoming galaxy and weak lensing surveys are providing us with an unprecedented map of the galaxy and matter distribution in the late time Universe. From these observations we can constrain fundamental physics such as the total mass of the neutrinos and the field content and dynamics of inflation. Doing so requires an accurate understanding of the non-linearities in the matter distribution and the mapping from the matter to the galaxy formation sites. The latter can be achieved by studying the clustering of peaks or extrema in the initial Gaussian field and following the subsequent evolution using perturbation theory. The goal of the research project will be to push this approach to the observational redshift space and statistics beyond the two-point functions, for instance the bispectrum. In a first step we will study the clustering of protohaloes in N-body simulations and compare it to non-perturbative calculations of the peak two- and three-point functions in Gaussian random fields. Subsequently we will study the halo velocities and displacements and employ them for the mapping to Eulerian space and redshift space.

*Project 4: **Detecting new particles in the sky*

The aim of this proposal is to develop the necessary tools to constrain signatures from massive particles in the cosmic microwave background (CMB) and apply developed tools directly to CMB data. Such particles are hypothesized in string theory and they have a well determined hierarchy. Interactions of these particles with the inflaton, leads to unique signatures in the CMB. Specifically, it can sources non-Gaussianities that can be observed in temperature and polarisation measurements. The predicted signatures can lead to coupling of primordial tensor and scalar degrees of freedom. Some numerical challenges need to be overcome, such as the fact that the intrinsic coupling between tensor and scalars will lead to less optimal computational scaling of the standard estimators. Furthermore, it would be the first time to include so-called B-mode polarisation in the constraints on NGs. This will require new simulations that include B-mode polarisation. Developed estimators will have to be tested for unforeseen biases, foreground contamination (e.g. polarised dust) and other sources of confusion. Methods need to be developed to mitigate these nuisances. The main outcome of this project will be the first analysis of CMB data looking for massive particles in CMB polarisation data.

These PhD studentships are funded by STFC as part of a new Centre for Doctoral Training in Data Intensive Science which also fosters industrial engagement. These four year CDT studentships will include several training courses in data science in the first year and a flexible six month placement with one or two industrial partners. Applicants should have a masters degree in mathematics or physics (with a major in theoretical physics or astrophysics) and should be UK or EU nationals. Preliminary enquiries to contact potential supervisors should be made to James Parke (gr-secretary@damtp.cam.ac.uk), the CTC Administrator.

In order to be considered for one of these studentships please submit a formal application to the PhD in Applied Mathematics and Theoretical Physics, University of Cambridge via the University’s Graduate Admissions website (for more information on this please visit http://www.graduate.study.cam.ac.uk/how-do-i-apply); and send an expression of interest email to grad-administrator@maths.cam.ac.uk explaining which studentship you are interested in and why. Expressions of interest letters that briefly describe your motivation for the project should be sent to grad-administrator@maths.cam.ac.uk when you apply.

Applications can be submitted online until the closing date of 29th June 2017, but candidates should make some expression of interest as soon as possible.

**Please note that applications will be reviewed on a rolling basis as they are received. Some offers may be made before the closing date.**

The University values diversity and is committed to equality of opportunity. The Department would particularly welcome applications from women, since women are, and have historically been, underrepresented on our student cohort.

**Group postdocs**

The GR/CTC group regularly advertises Stephen Hawking Advanced Fellowships for outstanding candidates in Cosmology and Gravitation with a tenure of 4-5 years. We also hold a large STFC consolidated grant which funds a number of postdoctoral positions in cosmology and relativity. These posts, if available, will be listed on this page (and elsewhere, usually in the autumn).

**External funding opportunities**

There are also a number of postdoctoral research fellowship opportunities that can be held within DAMTP. These include the STFC Ernest Rutherford Fellowship, which is offered every year. The deadline for applications is in September, but interested applicants who wish their Fellowship to be hosted in DAMTP must have discussed their application with a member of the DAMTP academic staff, who will act as their "sponsor" should their application be successful. The deadline for DAMTP to receive applications is usually in August. More information about this award can be found on the DAMTP vacancy page.

Other postdoctoral funding opportunities include the Royal Society, which offers five-year fellowships, the Dorothy Hodgkin Fellowship and Newton International Fellowships. The European Union offers funding for researchers (with its Marie Curie Fellowship), as does the Royal Astronomical Society and the University of Cambridge with the Herchel Smith Fellowship.

**PhD opportunities**

Entry requirements:

For those interested in taking a PhD in the GR/CTC group, this would normally be possible when the candidate has taken the University's Part III Mathematics course or an equivalent four-year degree, achieving a Distinction or first-class honours degree (though in practice most candidates come through Part III). Graduates from outside Cambridge frequently take Part III as a qualifying fourth-year course. Exceptional external applicants with masters degrees may be considered in cosmology or if there are other opportunities advertised on this website.

DAMTP deadline:

The deadline for applications is the end of January each year, unless you require funding from the Cambridge Trusts, in which case earlier deadlines apply. However, later applications will be considered where possible. For more detailed information please go to http://www.damtp.cam.ac.uk/study/phdstudentships.html and http://www.maths.cam.ac.uk/postgrad/phd/

Funding:

There are other awards available from Cambridge sources outside DAMTP. The Graduate Admissions website contains an up-to-date guide. See also the Student Registry for funding-related information.