Research Fellow in Quantum Technology for Fundamental Physics Ref 5283

School/department:  School of Mathematical Sciences/Dept of Physics and Astronomy
Hours: full time or part time hours considered up to a maximum of 1.0 FTE. Requests for flexible working options will be considered (subject to business need).
Contract: fixed term for up to 36 months, or 30 April 2024, whichever earliest.
Reference: 5283
Salary: starting at £33,797 to £40,322 per annum, pro rata if part time
Placed on: 20 January 2021
Closing date: 19 February 2021.   Applications must be received by midnight of the closing date.
Expected Interview date: Last week of February 2021
Expected start date: as soon as possible, 1 September 2021 at the very latest

Job description

We invite applications for two full-time postdoctoral positions in Quantum Technology for Fundamental Physics within the ITCM Group at the University of Sussex, led by Prof Matthias Keller.

This position is funded by the UK ‘Network of clocks for measuring the stability of fundamental constants’ consortium (QSNET). The consortium aims to build a network of dissimilar clocks to search for spatio-temporal changes in fundamental constants. Our partners in the network are the National Physical Laboratory, Imperial College London, and the University of Birmingham. 

The goal of the project at Sussex is to measure the frequency of a vibrational transition in molecular nitrogen ions with unparalleled precision and compare it with an electronic transition in calcium ions. The nitrogen ion's vibrational transition and the calcium ion's electronic transition exhibit different sensitivities to the proton-to-electron mass ratio, and therefore any relative changes in the frequencies of these transitions can be used to establish the degree to which the proton-to-electron mass ratio is constant.

In order to measure the vibrational frequency, a single nitrogen ion will be trapped alongside a single calcium ion. The calcium ion will serve as the read-out of the state of the molecule using a quantum logic spectroscopy scheme. A second ion trap system, which will hold a single calcium ion, will be used as a reference for the frequency comparison. 

The project will employ existing systems in the ITCM Group at Sussex and expand it in order to facilitate the frequency comparison. With the two ion traps and the molecular beam line in place, the focus of the project will be to expand the laser system for the vibrational frequency measurement, implement the quantum logic spectroscopy scheme and measure of the frequency ratio of the transitions within nitrogen and calcium.

The postholder will benefit from close interactions with the Sussex Theoretical Particle Physics (TPP)  and Mathematical Physics (MP) groups at the University of Sussex.

The following materials should be sent by email to and quoting the job reference number above.

-       Official Sussex application form (available via the University website

-       CV, list of publications, and statement of research interests in a single pdf document

-       Three recommendation letters.

Potential candidates are strongly encouraged to make informal contact with Prof. Matthias Keller (

The University of Sussex values the diversity of its staff and students and we welcome applicants from all backgrounds.

Download job description and person specification Ref 5283 [PDF 171.07KB]

How to apply

Download our academic application form [DOC 199.50KB] and Personal details and equal opportunties form [DOC 108.50KB] 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 in PDF format (we are unable to accept applications as or .pages) 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 [PDF 11.39KB]

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