Welcome to the Computational Nonlinear and Quantum Optics group website. The group is part of the Optics Division in the Department of Physics at the University of Strathclyde.

CNQO is one of the largest research groups in the department. The group applies theoretical and computational approaches to investigate problems associated with the fundamental nature of light-matter interactions as well as the capabilities of nonlinear optical devices based on or using laser light. It has state-of-the-art computational facilities and is a pioneer in the use of visual simulation to study nonlinear optical phenomena. It has its own network of UNIX workstations and connections to top-of-the-range computational facilities for parallel calculation and virtual reality graphics funded under collaborative multi-disciplinary projects. There are extensive research collaborations with groups in the EU via substantial European research grants, Australia, Japan, Russia, and the USA.

Group Co-ordinator: Prof. Gian-Luca Oppo
e-mail: g.l.oppo-at-strath.ac.uk
Tel: +44 141 548 3761


Quantum sealing with classical wax

Figure 1John Jeffers, and co-workers at Heriot-Watt and Edinburgh Universities, have implemented a quantum digital signature protocol that does not require the quantum signature to be stored in quantum memory.

They use unambiguous state discrimination to identify (sometimes) definitely the nonorthogonal states that form the signature. This measured signature is stored in normal computer memory. The team members extend the technique using unambiguous state elimination which, when they cannot determine the signature precisely, allows them at least to say what it was not – increasing the chance that a signature-forger reveals themselves. The work has been selected as an Editor’s Suggestion in July 2014 Physical Review Letters, Phys. Rev. Lett. 113, 040502 (2014) and is spotlighted in the Viewpoint section of Physics.

Tunnelling Dynamics of many interacting atoms in an optical lattice

Image credit: University of Innsbruck

Quantum tunnelling manifests itself in a multitude of well-known microscopic phenomena. Experimental physicists in the group of Hanns-Christoph Nägerl in Innsbruck, Austria, in collaboration with CNQO theorist Andrew Daley have now directly observed atoms transmitted through up to five potential barriers under conditions where a single particle would not be able to move. The corresponding out-of-equilibrium many-body dynamics is both of fundamental interest, and sets the stage for further studies of complex models and dynamics far from equilibrium in quantum simulators. This work was published in the journal Science.

Diffraction Gratings for Chiral Molecules

The Journal of Physical Chemistry A

Recent work by Alison Yao together with Robert Cameron and Steve Barnett of the Glasgow Quantum Theory group made the front cover of Journal of Physical Chemistry A in May 2014. The paper reports a new method of using optical forces to separate chiral molecules. This could have applications in discriminating enantiomers of chiral molecules.




STEA LogoCongratulations to Gian-Luca Oppo who was awarded Most Enthusiastic Teacher at the Strathclyde Teaching Excellence Awards 2014. The award recognises lecturers who demonstrate enthusiasm about their particular subject, creating an exciting and inspiring learning environment for students. Their enthusiasm and passion for their subject encourages students to seek out further learning and they offer intellectually challenging experiences to students which are deemed enjoyable. Congratulations also to Nigel Langford, who won the award for the Most Supportive Teacher (and to Alison Yao, who was also nominated for an award).


We are very happy to welcome Prof Andrew Daley to the group.

Andrew’s research interests focus on the overlap between quantum optics and many-body physics, especially in systems of ultracold atoms. This work has applications to the use of atomic and molecular systems as quantum simulators of complex materials and other quantum technologies, as well as fundamental studies of out of equilibrium dynamics in quantum systems.

Dirac Medal Winner


Steve Barnett has been awarded the prestigious Institute of Physics 2013 Dirac Medal for his wide ranging contributions throughout optics research, which both inspire and lead experimental endeavours. This medal is awarded annually in recognition of outstanding contributions to theoretical physics.


Measuring Nothing

Highlight in Synopses of PhysicsDaniel OiJohn Jeffers and Václav Potoček have shown how to measure nothing. Specifically, they showed how to find out whether there are any photons in a quantum field without disturbing its coherence in the case the vacuum is not found. This requires that no information is gained about the number of photons in the field, apart from the fact that there is at least one.

They suggest using a three-level atom controlled by a laser to probe the field stored in a cavity using an adiabatic transition. Moreover, modelling suggests that the process is robust against common sources of imperfection. The results have been selected to be an Editor’s Suggestion in Physical Review Letters Phys. Rev. Lett. 110, 210504 (2013) and are spotlighted in the Synopsis section of Physics

Quantum physics fights against crime

Physicists at the University of Strathclyde and Heriot-Watt University have developed a new way of verifying electronic transactions using light.

Their approach uses photons to create digital signatures, the security of which are based on the laws of quantum physics. The team includes CNQO’s John Jeffers. Their advance could help tackle the huge burden of e-crime, which is estimated to cost £205 million in the UK retail sector alone. Their work, recently published in the journal Nature Communications, was reported on the BBC news website. More information can be found on the following pages: