Quantum measurement in living cells, and high-coherence electron bunches from cold atoms - Robert Scholten

“Quantum technology” normally conjures thoughts of computation and communication, but also has exciting potential applications in new ways of measuring things at the nanometre, particularly for biological systems. The nitrogen-vacancy (NV) defect centre in diamond is an especially promising single spin system for quantum measurements in biology. Our first experiments have demonstrated optically detected magnetic resonance (ODMR) of individual fluorescent nanodiamond nitrogen-vacancy centres inside living human HeLa cells, and measured their spin levels and spin coherence times while tracking their location and orientation with nanoscale precision. We have measured quantum coherence through Rabi and spin-echo sequences, and orientation with 1° angular precision, over long (>10 h) periods. Variations in the decoherence rates are linked to changes in the local environment inside the cells, representing a new non-destructive imaging modality for intracellular biology.
While quantum-based imaging is an exciting prospect, even classical imaging is a vexing problem at the atomic scale, where there is enormous potential for example to determine the structure of bio-molecules. We have recently demonstrated a new source of high-coherence electron bunches based on photoionisation of laser-cooled atoms. With laser control of the cold atom cloud, we can shape the electron bunches, and because the electrons are so cold, they retain their shape during propagation. We have created “the world’s most expensive TV”, with a new bunch shape every frame – allowing the control needed to generate ultra-high-brightness bunches for coherent diffractive imaging at nanometer and femtosecond resolution.
LP McGuinness, Y Yan, A Stacey, DA Simpson, LT Hall, D Maclaurin, S. Prawer, P Mulvaney, J Wrachtrup, F Caruso, RE Scholten and LCL Hollenberg, Nature Nanotechnology 6 358 (2011)
AJ McCulloch, DV Sheludko, M Junker, SC Bell, SD Saliba, KA Nugent and Scholten, R. E. Nature Physics 7 785 (2011)