title: Motion and gravity effects in the precision of quantum clocks.
abstract: We show that motion and gravity affect the precision of quantum clocks. We consider a localised quantum field as a fundamental model of a quantum clock moving in spacetime and show that its state is modified due to changes in acceleration. By computing the quantum Fisher information we determine how relativistic motion modifies the ultimate bound in the precision of the measurement of time. While in the absence of motion the squeezed vacuum is the ideal state for time estimation, we find that it is highly sensitive to the motion-induced degradation of the quantum Fisher information. We show that coherent states are generally more resilient to this degradation and that in the case of very low initial number of photons, the optimal precision can be even increased by motion. These results can be tested with current technology by using superconducting resonators with tunable boundary conditions.
authors.affiliation: Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Göteborg, Sweden.
authors.forename: Joel
authors.initials: J
authors.lastname: Lindkvist
authors.affiliation: School of Mathematical Sciences, University of Nottingham, University Park, Nottingam NG7 2RD, United Kingdom.
authors.forename: Carlos
authors.initials: C
authors.lastname: Sabín
authors.affiliation: Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Göteborg, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Johansson
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Ivette
authors.initials: I
authors.lastname: Fuentes