We have proposed schemes for testing the limits of quantum mechanics which rely on levitating nanodiamonds containing nitrogen-vacancy (NV-) centres. We would like to put the spin of an NV- centre into a superposition and then use an inhomogeneous magnetic field to translate this into a spatial superposition, so that the diamond tries out being in two places at once. The photo shows one of our levitated nanodiamonds as a green dot (due to the green laser light we are shining onto it). Guy Stimpson, Angelo Frangeskou and Anis Rahman are working on this project which is a collaboration with the groups of Peter Barker and Sougato Bose (UCL), Myungshik Kim (Imperial) and Hendrik Ulbricht (Southampton).
More details are in our papers:
8. Ryan J Marshman, Anupam Mazumdar, Gavin W Morley, Peter F Barker, Steven Hoekstra & Sougato Bose, Mesoscopic Interference for Metric and Curvature (MIMAC) & Gravitational Waves, arXiv:1807.10830 (2018).
7. AC Frangeskou, ATMA Rahman, L Gines, S Mandal, OA Williams, PF Barker & GW Morley, Pure nanodiamonds for levitated optomechanics in vacuum, New Journal of Physics 20, 043016 (2018). Open access, open data.
6. ATM Anishur Rahman, AC Frangeskou, PF Barker & GW Morley, An analytical model for the detection of levitated nanoparticles in optomechanics, Review of Scientific Instruments 89, 023109 (2018). Open access, open data.
5. S Bose, A Mazumdar, GW Morley, H Ulbricht, M Toroš, M Paternostro, A Geraci, P Barker, MS Kim & G Milburn, A Spin Entanglement Witness for Quantum Gravity, Physical Review Letters 119, 240401 (2017), arXiv preprint. Highlighted in popular press including PRL Synopsis, New Scientist, Quanta and The Atlantic.
4. C Wan, M Scala, GW Morley, ATMA Rahman, H Ulbricht, J Bateman, PF Baker, S Bose, MS Kim, Free Nano-Object Ramsey Interferometry for Large Quantum Superpositions, Physical Review Letters 117, 143003 (2016). Open access.
2. C Wan, M Scala, S Bose, AC Frangeskou, ATMA Rahman, GW Morley, PF Barker & MS Kim, Tolerance in the Ramsey interference of a trapped nanodiamond, Physical Review A 93, 043852 (2016), arXiv preprint
1. M Scala, MS Kim, GW Morley, PF Barker & S Bose, Matter-wave interferometry of a levitated thermal nano-oscillator induced and probed by a spin, Physical Review Letters 111, 180403 (2013), arXiv preprint