Our paper Displacemon electromechanics: How to detect quantum interference in a nanomechanical resonator has been accepted by Physical Review X. This is our first paper from Lancaster!

To predict the behaviour of small particles, for example electrons moving through a semiconductor, it is essential to use the concept of quantum superposition—objects may traverse multiple paths simultaneously. When these paths recombine, we see a quantum interference pattern that cannot be explained using one path alone. In the words of Richard Feynman describing an experimental demonstration of this phenomenon, it “has in it the heart of quantum mechanics.” Such superpositions states have now been beautifully demonstrated for photons and single trapped atoms; however, it remains an exciting open question why larger objects do not usually show this behaviour.

Currently, the largest objects that demonstrate quantum interference are molecules comprising hundreds of atoms fired through gratings. While progress continues with molecule interferometry, alternative avenues are being opened in experimental quantum science to pursue this goal. Can we perform a quantum interference experiment with a much larger object containing, say, a million atoms? This paper demonstrates how a vibrating string—a carbon nanotube—connected to a superconducting quantum electronic circuit can answer that question.