October 2, 2020
Published by Stephan Sponar
Free quantum particles can posess a property which seems to defy classical physics. Namely they can orbit around a central axis without a restoring force. This property known as *free particle orbital ***angular momentum** has been observed in photons, electrons and recently also neutrons. We are investigating the latter for applications in neutron scattering, quantum information and quantum contextuality. If succesfully generated in neutrons orbital angular momentum would represent the 4th available degree of freedom in neutron *quantum information* and *contextuality* experiments, in addition to spin, energy and position.

October 16, 2017
Published by Stephan Sponar
Influence of *rotation* on the **phase** of light passing through an optical interferometer has been theortically investigated over a century. The **Sagnac effect** predicted the observation of a phase shift proportional to the scalar product of the *rotation frequency* and the area of the *interferometer*. In 1988 B. Mashhoon predicted a new relativistic quantum mechanical effect, i.e., a coupling of *spin* with the angular velocity of a *rotating* reference system. Following the prediction, the spin-rotation interaction has been successfully derived from the Dirac theory, a concrete measurement however is still missing. The first proposal in this regard in- cluded a measurement via neutron-interferometry.

November 28, 2016
Published by Stephan Sponar
In general a quantum system’s state vector carries *phase* information, a non-physical property that cannot be measured in an intensity measurement. However, a phase difference between states vectors is a physical quantity, giving rise to the phenomenon of *interference*. Phase accumulation is, at first sight, a consequence of dynamics of the state evolutions. In addition to and independent of this dynamical phase M. V. Berry discovered in the beginning of the eighties of the last century a phase due to the **geometrical** origin of the state evolution independent of its dynamical properties.