Theory

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Geometric Phases

November 28, 2016 Published by

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.

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Spin-Rotation Coupling

October 16, 2016 Published by

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.