Searching for spacetime granularity: analyzing a concrete experimental setup

Abstract

Abstract. In this work we show that the spin pendulum techniques developed by the Eöt-Wash group could be used to put very stringent bounds on the free parameters of a Lorentz invariant phenomenological model of quantum gravity. The model is briefly described as well as the experimental setup that we have in mind.

Experimental search for a Lorentz invariant spacetime granularity: Possibilities and bounds

“…The Eöt-Wash group had developed an experimental technique consisting of a continuously rotating torsion balance which involves approximately 10 23 horizontally polarized electrons possessing negligible magnetic moment [42]. Therefore, some of us were impelled to take advantage of this existing technology and propose a compatible experimental setting [43] for testing the model here presented. Later, the Eöt-Wash group performed the experiment suggested in Ref.…”

“…Later, the Eöt-Wash group performed the experiment suggested in Ref. [43] which resulted in bounds on some of the free parameters of the model, corresponding to the features the experiment was sensitive to. This is the subject of the next section.…”

Search for a proposed signature of Lorentz-invariant spacetime granularity

“…where is a fermion field, γ μ are the usual Dirac matrices, and μν is an antisymmetric rank-2 tensor constructed from the Weyl curvature and the parameters of the Corichi-Sudarsky model. Bonder and Sudarsky [3][4][5] modified the original proposal [2] to eliminate various ambiguities and evaluated a particular case where a polarized electron at rest in the laboratory frame is subject to the quadrupole gravitational fields of the earth and an orientable laboratory quadrupole source, plus the 'frame-dragging' effect of the earth's angular momentum. They argued that in this situation an electron with its spin lying in the horizontal plane at an azimuthal angle φ measured counterclockwise from local west should feel a vertical torque [5]:…”