PhD Studentship: Photon Correlations and Information Dynamics in Atomic Ensembles and Molecules

Primary supervisor - Dr Magnus Borgh 

Quantum optics provides powerful methods for determining and quantifying the quantum-mechanical nature of systems and processes, providing fundamental tools for the rapidly developing quantum technologies. Quantum-optical measurements become especially intriguing in systems such as atomic ensembles or molecular processes whose quantum nature remains unclear. These open quantum systems can range from Markovian (“no memory”) to non-Markovian, where information is exchanged in both directions between system and environment. The relationships between light emission, quantum coherence, and non-Markovianity therefore become important both for fundamental physics and for eventual practical applications. 

In this PhD project, we will develop the theory for quantum-optical protocols for interrogating systems ranging from atomic ensembles to molecules. A fundamental indicator of quantum behaviour in light-matter interactions is two-photon correlations. Cooperative effects are known to enhance quantum behaviour in atomic arrays [1]. We ask how the quantum dynamics changes when such systems are placed in optical cavities. We have previously shown that photon correlations can reveal information about the vibrational (phonon) dynamics of a molecule’s interactions with its environment [2]. We will extend this to, e.g., complex molecules, ultimately seeking to identify photonic signatures of non-Markovianity. For sufficiently Markovian systems, the photon-photon correlations can be computed using the quantum regression theorem together with a Lindblad equation for atomic ensembles or a HEOM model of a molecular system. For non-Markovian systems one must proceed with care but methods for computing correlation functions beyond the quantum regression theorem have been proposed [3]. An ultimate goal will be to develop these to allow accurate predictions of photon-correlation signatures also more generally in the non-Markovian regime. 

[1] Williamson, Borgh & Ruostekoski, Phys. Rev. Lett 125, 073602 (2020) 

[2] Humphries, Green, Borgh & Jones, Phys. Rev. Lett 131, 143601 (2023) 

[3] Goan, Chen, & Jian, J. Chem. Phys. 134, 124112 (2011).  

Entry requirements

The standard minimum entry requirement is 2:1 Physics, Physical Sciences, Chemistry, Natural Science, Mathematics.

Mode of study

Full-time

Start date

1 October 2026

Funding

This PhD project is in a competition for a Faculty of Science funded studentship. Funding is available to UK applicants and comprises ‘home’ tuition fees and an annual stipend for 3 years.

Closing Date

10/12/2025

To apply for this role, please click on the 'Apply' button above.

Advert information