## Gravitational time dilation in quantum mechanics

*SPECIAL VENUE: Sir James Foots Building, 47A-141*

Dr Magdalena Zych, UQ (ARC Centre of Excellence for Engineered Quantum Systems)

* This colloquium will be held at 3 pm on Friday 31st July.*

Phenomena stemming jointly from quantum theory and general relativity are often thought to be relevant only at high energies and and in strong gravitational fields. Here we consider low-energy quantum systems under weak time dilation and show that the latter leads to novel quantum phenomena. We focus on a quantum version of the “twin paradox’’: where a single a system is brought in superposition of being at two different gravitational potentials. Time dilation in general leads to entanglement between internal degrees of freedom and a position of a composite particle. The resulting effects could be tested in earth-based interference experiments with atoms, molecules (or photons). We further derive that time dilation causes universal decoherence of composite quantum systems, which becomes substantial already for micro-scale objects. Thus far the regime of low-energy composed quantum systems in weak gravitational fields was largely neglected in theoretical research. Our results show that its new phenomena might finally allow testing the interplay between quantum theory and general relativity and can even be relevant for transition to classicality.

Dr Magdalena Zych – Gravitational time dilation in quantum mechanics from School of Mathematics & Physics on Vimeo.