Quantum Nature of Gravity in the Lab: Assumptions, Implementation and Applications on the Way

With Sougato Bose, University College London

Abstract: There is no empirical evidence yet as to “whether” gravity has a quantum mechanical origin. Motivated by this, I will present a feasible idea for testing the quantum origin of the Newtonian interaction based on the simple fact that two objects cannot be entangled without a quantum mediator. I will show that despite its weakness, gravity can detectably entangle two adjacent micron sized test masses held in quantum superpositions even when they are placed far apart enough to keep Casimir-Polder forces at bay. A prescription for witnessing this entanglement through spin correlations is also provided. Further, I clarify the assumptions underpinning the above proposal such as our reasonable definition of “classicality”, as well as relativistic causality. We note a few ways to address principal practical challenges: Decoherence, Screening EM forces and Inertial noise reduction. I will also describe how unprecedented compact sensors for classical gravity (including meter scale sensors for low frequency gravitational waves) will arise on the way to the above grand goal.

Register in advance for this webinar:

Organisers: Murray Batchelor (ANU), Nicole Bell (Melbourne), Gavin Brennan (Macquarie), Eric Cavalcanti (Griffith), Susan Coppersmith (UNSW), Archil Kobakhidze (Sydney), Sergei Kuzenko (UWA), Karen Livesey (Newcastle), Meera Parish (Monash), Margaret Reid (Swinburne), James Zanotti (Adelaide), Magdalena Zych (UQ)

Host presenter: David Tilbrook (ANU)