Jay D. Tasson

Quantum tests of the Einstein Equivalence Principle with the STE-QUEST space mission

We present in detail the scientific objectives in fundamental physics of the Space-Time Explorer and QUantum Equivalence Space Test (STE-QUEST) space mission. STE-QUEST was pre-selected by the European Space Agency together with four other missions for the cosmic vision M3 launch opportunity planned around 2024. It carries out tests of different aspects of the Einstein Equivalence Principle using atomic clocks, matter wave interferometry and long distance time/frequency links, providing fascinating science at the interface between quantum mechanics and gravitation that cannot be achieved, at that level of precision, in ground experiments. We especially emphasize the specific strong interest of performing equivalence principle tests in the quantum regime, i.e. using quantum atomic wave interferometry. Although STE-QUEST was finally not selected in early 2014 because of budgetary and technological reasons, its science case was very highly rated. Our aim is to expose that science to a large audience in order to allow future projects and proposals to take advantage of the STE-QUEST experience.

Lorentz violation, gravitomagnetism, and intrinsic spin

A largely unconstrained set of relativity-violating effects is studied via the gravitomagnetic effect on intrinsic spins. The results of existing comagnetometer experiments are used to place constraints on two new combinations of these effects at the 10% level. We show that planned improvements in these experiments will make them competitive with the best existing sensitivities to this elusive class of relativity-violating effects. Prospects for measuring the conventional general-relativistic gravitomagnetic effect are also considered.

Matter-sector Lorentz violation in binary pulsars

Violations of local Lorentz invariance in the gravitationally coupled matter sector have yet to be sought in strong-gravity systems. We present the implications of matter-sector Lorentz violation for orbital perturbations in pulsar systems and show that the analysis of pulsar data can provide sensitivities to these effects that exceed the current reach of solar system and laboratory tests by several orders of magnitude.

Gravity effects on antimatter in the standard-model extension

The gravitational Standard-Model Extension (SME) is the general field-theory based framework for the analysis of CPT and Lorentz violation. In this work we summarize the implications of Lorentz and CPT violation for antimatter gravity in the context of the SME. Implications of various attempts to place indirect limits on anomalous antimatter gravity are considered in the context of SME-based models.

Observer and Particle Transformations and Newton's Laws

A frequently confused point in studies of symmetry violation is the distinction between observer and particle transformations. In this work, we consider a model in which a coefficient in the Standard-Model Extension leads to violations of rotation invariance in Newtons second law. The model highlights the distinction between observer and particle transformations.

Superconducting-Gravimeter Tests of Local Lorentz Invariance

Superconducting-gravimeter measurements are used to test the local Lorentz invariance of the gravitational interaction and of matter-gravity couplings. The best laboratory sensitivities to date are achieved via a maximum-reach analysis for 13 Lorentz-violating operators, with some improvements exceeding an order of magnitude.

Lorentz Symmetry and Matter-Gravity Couplings

This proceedings contribution summarizes recent investigations of Lorentz violation in matter-gravity couplings.

Macroscopic Objects, Intrinsic Spin, and Lorentz Violation

The framework of the Standard-Model Extension (SME) provides a relativistic quantum field theory for the study of Lorentz violation. The classical, nonrelativistic equations of motion can be extracted as a limit that is useful in various scenarios. In this work, we consider the effects of certain SME coefficients for Lorentz violation on the motion of macroscopic objects having net intrinsic spin in the classical, nonrelativistic limit.

Status of Matter-Gravity Couplings in the SME

Constraints on Lorentz violation in matter-gravity couplings are summarized along with existing proposals to obtain sensitivities that exceed current limits by up to 11 orders of magnitude.

Gravitational Searches for Lorentz Violation with Matter and Astrophysics

This contribution to the CPT16 proceedings summarizes recent tests of Lorentz violation in the pure-gravity sector with cosmic rays and reviews recent progress in matter-gravity couplings.