Exploring fundamental physics with levitated nano-oscillators

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Prof. Peter Barker, University College London
This colloquium will be held at 11 am, 9th August, in  Bldg.: Richards (05), Room #213
Abstract:
Nanoscale oscillators levitated by optical, electric or magnetic fields in high vacuum offer a completely new arena for studies of quantum and foundational science. Levitation allows extreme isolation from the environment, reducing the noise and decoherence processes that can destroy delicate quantum states. The oscillator’s properties can be widely tuned via control of the levitating fields and even cooled to microkelvin temperatures. The relatively large mass of trapped nanoparticles, when compared to microscopic quantum systems such as trapped atoms or ions, means that these oscillators operate in a unique regime where they are small enough to be quantum systems, but large enough that the effects of gravity become important. They are therefore seen as a promising laboratory-based platform that can be used to explore the role of gravity in quantum mechanics.
In this colloquium, I will give an overview of levitated nano-oscillator experiments that are currently being developed. This includes tests of the quantum superposition principle at large mass scales and of models for macroscopic wavefunction collapse. I will also describe how levitated oscillators have been used for measurements of weak, short-range forces. The methods that have been developed for cooling and control of the oscillator’s center-of-mass motion will be outlined before addressing recent work that has made the first tests of wavefunction collapse using a single, levitated nanosphere