Constraining Spacetime Nonmetricity with Neutron Spin Rotation in Liquid He-4

Abstract

General spacetime nonmetricity coupled to neutrons is studied. In this context, it is shown that certain nonmetricity components can generate a rotation of the neutron's spin. Available data on this effect obtained from slow-neutron propagation in liquid helium are used to constrain isotropic nonmetricity components at the level of 10−22GeV. These results represent the first limit on the nonmetricity ζ2(6)S000 parameter as well as the first measurement of nonmetricity inside matter.