2 research outputs found
Atom Interferometry tests of the isotropy of post-Newtonian gravity
We present a test of the local Lorentz invariance of post-Newtonian gravity
by monitoring Earth's gravity with a Mach-Zehnder atom interferometer that
features a resolution of about 8*10^(-9)g/Hz^(1/2), the highest reported thus
far. Expressed within the standard model extension (SME) or Nordtvedt's
anisotropic universe model, the analysis limits four coefficients describing
anisotropic gravity at the ppb level and three others, for the first time, at
the 10ppm level. Using the SME we explicitly demonstrate how the experiment
actually compares the isotropy of gravity and electromagnetism.Comment: Added outlook, corrected typos; to appear in PRL. 4 pages, 3 figure
Atom interferometry tests of local Lorentz invariance in gravity and electrodynamics
We present atom-interferometer tests of the local Lorentz invariance of
post-Newtonian gravity. An experiment probing for anomalous vertical gravity on
Earth, which has already been performed by us, uses the highest-resolution
atomic gravimeter so far. The influence of Lorentz violation in electrodynamics
is also taken into account, resulting in combined bounds on Lorentz violation
in gravity and electrodynamics. Expressed within the standard model extension
or Nordtvedt's anisotropic universe model, we limit twelve linear combinations
of seven coefficients for Lorentz violation at the part per billion level, from
which we derive limits on six coefficients (and seven when taking into account
additional data from lunar laser ranging). We also discuss the use of
horizontal interferometers, including atom-chip or guided-atom devices, which
potentially allow the use of longer coherence times in order to achieve higher
sensitivity.Comment: Reference added; corrected factor of 2 in Tab. IV and V. 12 pages, 4
figures, 6 table