Synthetic Unruh effect in cold atoms

TL;DR

This paper proposes a method to simulate the Unruh effect using ultracold atoms in optical lattices, enabling observation of thermal quantum fluctuations associated with accelerated observers.

Contribution

It introduces a novel quantum simulation approach for the Unruh effect with ultracold atoms, including state preparation, lattice quench, and fluctuation measurement techniques.

Findings

Fluctuations exhibit thermal spectra consistent with Unruh's prediction

Observation of Bose-Einstein to Fermi-Dirac distribution transition

Simulation framework applicable to quantum field phenomena in curved spacetime

Abstract

We propose to simulate a Dirac field near an event horizon using ultracold atoms in an optical lattice. Such a quantum simulator allows for the observation of the celebrated Unruh effect. Our proposal involves three stages: (1) preparation of the ground state of a massless 2D Dirac field in Minkowski spacetime; (2) quench of the optical lattice setup to simulate how an accelerated observer would view that state; (3) measurement of the local quantum fluctuation spectra by one-particle excitation spectroscopy in order to simulate a De Witt detector. According to Unruh's prediction, fluctuations measured in such a way must be thermal. Moreover, following Takagi's inversion theorem, they will obey the Bose-Einstein distribution, which will smoothly transform into the Fermi-Dirac as one of the dimensions of the lattice is reduced.