Gravitational Redshift Tests with Atomic Clocks and Atom Interferometers

authored by
Fabio Di Pumpo, Christian Ufrecht, Alexander Friedrich, Enno Giese, Wolfgang P. Schleich, William G. Unruh

Atomic interference experiments can probe the gravitational redshift via the internal energy splitting of atoms and thus give direct access to test the universality of the coupling between matter-energy and gravity at different spacetime points. By including possible violations of the equivalence principle in a fully quantized treatment of all atomic degrees of freedom, we characterize how the sensitivity to gravitational redshift violations arises in atomic clocks and atom interferometers, as well as their underlying limitations. Specifically, we show that: (i) Contributions beyond linear order to trapping potentials lead to such a sensitivity of trapped atomic clocks. (ii) Bragg-type interferometers, even with a superposition of internal states, with state-independent, linear interaction potentials are at first insensitive to gravitational redshift tests. However, modified configurations, for example by relaunching the atoms, can mimic such tests under certain conditions and may constitute a competitive alternative. (iii) Guided atom interferometers are comparable to atomic clocks. (iv) Internal transitions lead to state-dependent interaction potentials through which light-pulse atom interferometers can become sensitive to gravitational redshift violations.

Institute of Quantum Optics
External Organisation(s)
Ulm University
Technische Universität Darmstadt
German Aerospace Center (DLR)
Texas A and M University
University of British Columbia
PRX Quantum
No. of pages
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Physics and Astronomy(all), Computer Science(all), Applied Mathematics, Mathematical Physics, Electronic, Optical and Magnetic Materials, Electrical and Electronic Engineering
Electronic version(s) (Access: Open) (Access: Open)