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:
7. 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 and New Scientist.
6. ATM Anishur Rahman, AC Frangeskou, PF Barker & GW Morley, Interferometric detection in levitated optomechanics, Review of Scientific Instruments 89, 023109 (2018). Open access.
5. AC Frangeskou, ATMA Rahman, L Gines, S Mandal, OA Williams, PF Barker & GW Morley, Optical levitation of high purity nanodiamonds in vacuum without heating, arXiv:1608.04724 (2016)
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