PhD project: Self-organized atomic phases via diffractive light coupling

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University of Strathclyde
27 September, 2019


Department of Physics Glasgow
United Kingdom


Recent years have seen huge progress in using well controlled cold atom systems to simulate complex quantum phases. Many schemes involve light-mediated coupling in cavities or free space. Among others, magnetic ordering and supersolids have been of particular interest. The project will analyze a conceptually simple scheme to achieve light mediated coupling which is based on a laser-cooled or quantum degenerate atomic ensemble irradiated by a detuned laser beam. It has a theoretical focus but will strongly collaborate with experimentalists at the University of Strathclyde and the Université Côte d’Azur.

We have first demonstrations that any degree of freedom of light on the Poincare sphere can be used to couple atomic degrees of freedom leading to new phases. Optomechanical nonlinearities coupling to the amplitude of the light field lead to atomic crystallization [1,2], optical pumping nonlinearities to magnetic ordering in close analogy to the transverse Ising model [3], coherent population trapping to magnetic quadrupole states [4]. The project will use state-of-the-art analytical and numerical methods with the objectives :

• To provide a theoretical analysis of a plethora of unexplored phenomena observed experimentally following [1, 3,4], in particular the competition between polar and nematic structures (dipole and quadrupolar magnetic states) and the coupling between optomechanical and magnetic degrees of freedom.
• To work out the connections of the observed transitions to phase transitions in statistical mechanics.
• To provide guidance to further experiments.
• To develop further the theory for quantum-degenerate gases [5] to guide corresponding experiments.

Skills acquired will include
• Mastering demanding computational projects.
• Mastering analytical techniques of stability analysis.
• Mastering state-of-the-art quantum problems.
• Understanding of complex, nonlinear systems involving feedback.
• Obtaining international and collaborative research experience.
• Preparing for a career in a variety of fields including the emerging quantum technologies.

The studentship is embedded in a collaboration between the Computational Nonlinear and Quantum Optics Group (G.R. M. Robb, G.-L. Oppo) and the Experimental Quantum Optics and Photonics Group (T. Ackemann) at Strathclyde. The studentship will include placements to the group of R. Kaiser and G. Labeyrie, INPHYNI, Université Côte d’Azur.
Professional development opportunities are provided via the Scottish Universities Physics Alliance (SUPA) Graduate School, and the Postgraduate Certificate in Researcher Professional Development at Strathclyde.



[1] G. Labeyrie, E. Tesio, P. M. Gomes, G.-L. Oppo, W. J. Firth, G. R. M. Robb, A. S. Arnold, R. Kaiser, and T. Ackemann. Nature Phot. 8,321-325 (2014)
[2] E. Tesio, G.R.M. Robb, T. Ackemann, W. J. Firth, G.-L. Oppo. Kinetic Theory for Transverse Optomechanical Instabilities. Phys. Rev. Lett. 112, 043901 (2014).
[3] I. Kresic, G. Labeyrie, G.R.M. Robb, G.-L. Oppo, P.M. Gomes, P. Griffin, R. Kaiser, and T. Ackemann. Spontaneous light-mediated magnetism in cold atoms. Communications Physics 1, 33 (2018)
[4] G. Labeyrie, I. Kresic, G.R.M. Robb, G.-L. Oppo, R. Kaiser, and T. Ackemann. Magnetic phase diagram of light-mediated spin structuring in cold atoms. Optica 5, 1322- 1328 (2018)
[5] G. R. M. Robb, E. Tesio, G.-L. Oppo, W. J. Firth, T. Ackemann, R. Bonifacio. Quantum Threshold for Optomechanical Self-Structuring in a Bose-Einstein Condensate. Phys. Rev. Lett. 114, 173903 (2015).

For more information, please contact g [dot] r [dot] m [dot] robb [at] strath [dot] ac [dot] uk or thorsten [dot] ackemann [at] strath [dot] ac [dot] uk.