Research Fellow in Precision Spectroscopy Ref 3244

School/department: School of Mathematical and Physical Sciences
Hours: full time
Contract: fixed term until November 2019 
Reference: 3244
Salary: starting at £32,548 and rising to £38,833 per annum
Placed on: 10 May 2018
Closing date: 8 June 2018.  Applications must be received by midnight of the closing date.
Expected interview date: As soon as possible
Expected start date: As soon as possible

Job description

Applications are invited for a full-time postdoctoral position in precision spectroscopy at the University of Sussex. Applicants should have obtained a PhD in experimental quantum optics, laser- or atomic/molecular physics and be able to demonstrate working knowledge in this field.

The laws of physics are governed by a set of fundamental constants which determine the structure of the universe from sub-atomic particles to large galaxy clusters. Many theories which aim to unify all fundamental forces and cosmological models predict that fundamental constants change in time. Two particularly interesting constants are the fine structure constant and the proton-to-electron mass ratio, both of which influence the internal structure of atoms and molecules.

At the ITCM group at Sussex, we have set up an experiment which aims to measure how the proton-to-electron mass ratio changes with time to a higher accuracy than currently possible by employing high resolution spectroscopy of molecular ions.

Single molecular ions are confined in time-varying electric fields (rf ion trap), and further localised via a co-trapped atomic ion that is laser cooled. By using quantum logic spectroscopy the quantum state of the molecule can be transferred to the atomic ion, due to the joint motion between the two ions within the trapping potential. In this way the ion’s state is measured without destroying it, which is problematic to achieve without the state transfer between the ions.

Utilizing this scheme the spectrum of the molecular ion can be measured very accurately and compared to an existing optical atomic clock via an optical frequency comb. Repeating this measurement over time, changes in the proton-to-electron mass ratio show as a change in the relative transition frequency of the atomic and molecular transitions.

The project is part of an interdisciplinary collaboration between the ITCM research group at Sussex and the research of Prof Tim Softley (University of Birmingham) and Dr Brianna Heazlewood (University of Oxford).

For further information please contact Prof Matthias Keller

Phone: +44 (1273) 877673, email:

Please include with your completed application form a CV, at least two references and a list of relevant publications.

The University of Sussex is committed to equality of opportunity

Download Job Description and Person Specification Ref 3244 [PDF 116.37KB]

How to apply

Download our academic post application form [DOC 301.50KB] and personal details and equal opportunities form [DOC 162.50KB] and fill in all sections.

Email your completed application, and personal details and equal opportunities form to

You should attach your application form and all documents to the email (don't use a web-based upload/weblink service) and use the format job reference number / job title / your name in the subject line.

You can also send your application by post to Human Resources Division, Sussex House, University of Sussex, Falmer, Brighton, BN1 9RH.

Download our terms and conditions summary for Research Faculty Terms and Conditions [DOC 36.00KB]

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