Gravity Probe Spin: Prospects for measuring general-relativistic precession of intrinsic spin using a ferromagnetic gyroscope

Testing the foundation of quantum physics in space via Interferometric and non-interferometric experiments with mesoscopic nanoparticles

“…For the numerical values of E L /a L employed we refer the interested reader to Supplementary Fig. beyond the standard model, when it comes to testing candidates of Dark Matter 5-10 and possible effects in particle interactions related to Dark Energy [11][12][13] ; the low-energy regime of the interplay between quantum mechanics and gravity 46,[104][105][106][107] ; precision tests of gravity 14,15,83,94,[108][109][110][111] ; the test of the equivalence principle and of general relativity's predictions, such as gravitational waves, in a parameter range complementary to existing experiments such as LIGO, VIRGO, GEO600, and the planned LISA space antenna 112,113 , and frame-dragging effects 114 . Furthermore, large-mass experiments in space will unavoidably provide a formidable platform for applications in Earth and planet observation 115,116 , where large-mass mechanical systems have already shown a superb capability as force and acceleration sensors 78,[117][118][119][120][121][122][123][124][125] , including in rotational mechanical modes 55,126 .…”

Observational constraints in metric-affine gravity

“…In the geometric scheme of MAG, not only an energymomentum tensor of matter arises as source of curvature, but also a hypermomentum density tensor which operates as source of torsion and nonmetricity. For the special case of Weyl-Cartan geometry it splits into spin and dilation currents, which carry their own charges and provide a RN type of solution (50) to the field equations of MAG. Following these lines, we compute the dynamical corrections provided by both spin and dilation charges in the main classical tests of gravity, namely the photon sphere, perihelion shift, gravitational redshift, Shapiro delay and deflection of light.…”

“…At the Earth scale, the microscopic signatures of torsion on the energy levels of minimally and nonminimally coupled Dirac spinors have been tested [44][45][46][47][48][49], whereas future tests based on the precession of ferromagnetic gyroscopes have also been successfully proposed [50]. In this sense, on account of the purely quantum nature of the intrinsic hypermomentum of matter, the performance of new experiments sufficiently sensitive to measure the splitting of the fermionic energy levels in strong gravitational regimes opens up promising prospects for testing post-Riemannian geometry [51].…”

“…For astrophysical systems, this condition holds since we receive the electromagnetic signal from an object which is far away from the source. Now, we take the solution (50), and assume the gravitational potential to be small ≈ 1, which means that…”

“…The photon time travel (89) cannot be analytically integrated for our RN type of solution (50). However, one can consider the corresponding effect at large distances (see Eq.…”