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Academic Staff

Dr James Millen

James Millen 

Telephone: +44 (0)20 7848 4686


Office: S6.31

Office Hours

Research GroupPhotonics & Nanotechnology Group


James joined King’s in 2018 as a Lecturer in Advanced Photonics, studying Opto- and Electromechanics with levitated nanoparticles. In 2017 James was awarded the David Bates Prize for his pioneering contributions to experimental and theoretical quantum optomechanics.

He completed his MSc in Physics at Imperial College London in 2007, and his Ph. D. in experimental atomic physics at Durham University in 2011, under the supervision of Dr. M. P. A. Jones. During this work he created the world’s first gas of ultra-cold strontium Rydberg atoms.

In 2011 James moved to University College London, to work with Prof. Peter Barker in the new field of levitated optomechanics. In pioneering work, they used focussed laser beams and optical cavities to cool and control the motion of charged silica nanoparticles. Together with Dr. Janet Anders they undertook a paradigmatic study into the non-equilibrium dynamics of a Brownian particle.

James was awarded a Marie Skłodowska-Curie Research Fellowship to work in the Quantum Nanophysics group of Prof. Markus Arndt at the University of Vienna between 2015-2018. The group developed techniques which will enable the exploration of the mass limit of quantum physics in uncharted regimes. While in Vienna, James pioneered the study of rotational optomechanics, developing the most frequency stable mechanical object ever created.

Public Engagement

To complement his research, James has fostered a keen interest in Outreach, Public Engagement, and Science Communication, and is currently Lecturer in Quantum Theory to the Public at the Royal Institution. He runs The Quantum Workshop mobile experiment, has written for the Guardian and Physics World, and has acted as scientific advisor for two BBC documentaries. More details can be found on his personal websites:

Twitter: @QuantumWorkshop


Research interests

  • Opto- and electro-mechanics
  • Nano-thermodynamics
  • Macroscopic quantum physics


Publication Highlights

For a full list of publications see


Nanoparticle detection in an open-access silicon microcavity

Stefan Kuhn, Georg Wachter, Franz-Ferdinand Wieser, James Millen, Michael Schneider, Johannes Schalko, Ulrich Schmid, Michael Trupke, Markus Arndt

Applied Physics Letters 111, 253107 (2017)


Optically driven ultra-stable nanomechanical rotor

Stefan Kuhn, Benjamin A. Stickler, Alon Kosloff, Fernando Patolsky, Klaus Hornberger, Markus Arndt, James Millen

Nature Communications 8, 1670 (2017)


Full Rotational Control of Levitated Silicon Nanorods

Stefan Kuhn, Alon Kosloff, Benjamin A. Stickler, Fernando Patolsky, Klaus Hornberger, Markus Arndt, James Millen

Optica 4, 356-360 (2017)


Nonlinear Dynamics and Strong Cavity Cooling of Levitated Nanoparticles

P. Z. G. Fonseca, E. B. Aranas, J. Millen, T. S. Monteiro, and P. F. Barker

Physical Review Letters 117, 173602 (2016)


Perspective: Quantum Thermodynamics

James Millen & André Xuereb

New Journal of Physics 18, 011002 (2016)


Cavity Cooling a Single Charged Levitated Nanosphere

J Millen, PZG Fonseca, T Mavrogordatos, TS Monteiro, PF Barker

Physical Review Letters 114, 123602 (2015)


Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere

J Millen, T Deesuwan, P Barker, J Anders

Nature Nanotechnology 9, 425–429 (2014)





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