Quantum time crystals and interacting chiral gauge theories in atomic Bose-Einstein condensates: Role of the Page-Wootters mechanism

We build the case that our published chiral soliton model [Phys. Rev. Lett. 123, 250402 (2019)] can lead to a genuine quantum time crystal for finite atom numbers. To do this we compare results from the chiral soliton model with exact numerical solutions for the ground state of the three-particle Schrödinger equation in the limit that the spatial profile of the soliton is largely independent of its center-of-mass motion. The connection between the two approaches is found via the Page-Wootters mechanism, and this is what allows for dynamical evolution even in the quantum ground state, as required for a genuine quantum time crystal.