Strong equivalence, Lorentz and CPT violation, anti-hydrogen spectroscopy and gamma-ray burst polarimetry

Abstract

The strong equivalence principle, local Lorentz invariance and CPT symmetry are fundamental ingredients of the quantum field theories used to describe elementary particle physics. Nevertheless, each may be violated by simple modifications to the dynamics while apparently preserving the essential fundamental structure of quantum field theory itself. In this paper, we analyse the construction of strong equivalence, Lorentz and CPT violating Lagrangians for QED and review and propose some experimental tests in the fields of astrophysical polarimetry and precision atomic spectroscopy. In particular, modifications of the Maxwell action predict a birefringent rotation of the direction of linearly polarised radiation from synchrotron emission which may be studied using radio galaxies or, potentially, gamma-ray bursts. In the Dirac sector, changes in atomic energy levels are predicted which may be probed in precision spectroscopy of hydrogen and anti-hydrogen atoms, notably in the Doppler-free, two-photon 1s − 2s and 2s − nd (n ∼ 10) transitions.

Einstein-Hilbert graviton modes modified by the Lorentz-violating bumblebee field

“…The Lorentz-violating (LV) terms, generated as vacuum expectation values of tensors defined in a high energy scale, are coupled to the physical fields yielding coordinate invariance and violation of Lorentz symmetry in the particle frames [11]. This theoretical framework has inspired a large number of investigations in the last several years, encompassing fermion systems [12][13][14][15][16][17][18][19][20], CPT-probing experiments [21][22][23][24][25][26][27], the electromagnetic CPT-and Lorentzodd term [28]- [41], the CPT-even and Lorentz-odd gauge sector and its interactions with fermions [42][43][44][45][46][47][48][49][50][51], [52][53][54][55][56][57]. Recent investigations involving higher dimensional operators [58][59][60], its possible connections with LV theories [61][62][63][64][65][66], and nonminimal couplings …”

Cold antihydrogen: a new frontier in fundamental physics

“…None of these investigations have detected a violation of the CPT theorem. However, antihydrogen would be the first pure antimatter system to be probed, and hydrogen is the simplest and one of the best studied atoms of all, making detailed comparisons with antihydrogen one of the most sensitive probes of the CPT theorem (Shore 2005). It is expected that no violations of CPT will be found.…”

Muon, positron and antiproton interactions with atoms and molecules

“…It is proposed to carry out tests of fundamental principles of physics using trapped antihydrogen. There is a very good article on the underlying theory by Shore [31]. For my summary with comments, see [32].…”