Electromagnetic acceleration of neutrons

Abstract

We note that the neutron spin must be treated as an intrinsically quantum variable when determining electromagnetically induced phase shifts in neutron interferometry by computing the otherwise-classical action over the classical orbit. We show that a putative acceleration of the neutron (y/wc)Ex (|iXB), recently suggested by Anandan, is essentially unobservable in such measurements over segments of the orbit where the electric and magnetic fields are constant (or vary slowly), within standard electroweak theory.

Neutron Interferometric Observation of Noncyclic Phase

“…It has since become known as the Pancharatnam connection [2][3][4]. Misconceptions (cf., e.g., [5][6][7]) about the noncyclic phase, however, persist. For a neutron spin precessing about a static magnetic field at an angle u, for instance, the phase acquired has been widely assumed (cf., e.g., [6,7]) to be one-half the precession angle for all u, the factor 1͞2 being ascribed to the spin magnitude.…”

“…Misconceptions (cf., e.g., [5][6][7]) about the noncyclic phase, however, persist. For a neutron spin precessing about a static magnetic field at an angle u, for instance, the phase acquired has been widely assumed (cf., e.g., [6,7]) to be one-half the precession angle for all u, the factor 1͞2 being ascribed to the spin magnitude. For polarized neutrons in rotating magnetic fields, Weinfurter and Badurek [5] mistook the rotation angle of the field to be the noncyclic geometric phase and thereby claimed to have measured this "phase" polarimetrically.…”

Electromagnetic Deflection of Spinning Particles

“…The current work, however, includes terms to all orders in the particle's velocity, not just the lowest-order limit of Anandan. It should also be noted that the criticisms of Casella and Werner [22] of Anandan's analysis [21] are erroneous, being based on an obvious omission of all "spin-flip" terms from their quantum mechanical equations of motion.…”

Inductance due to spin current

“…which recovers the same spin motive force (to leading order in E) derived rigorously from covariant derivative of the SU (2) gauge theory for spinful particles [29][30][31][32] . Another support of this classical formalism is that it derives the Rashba spin-orbit coupling (SOC) in condensed matter systems where Lorentz invariance is generally irrelevant.…”

“…We noticed that, following the discovery of Aharonov-Casher (AC) effect 47 , it has been recognized that a time-varying electric (E) field renders a spin motive force on spin 1/2 particles, which can be formulated within a SU (2) gauge theory that treats the spin as gauge charge [29][30][31][32] . Owing to this spin motive force, we show that when a spin current changes with time, the Lorentz boost of the spins creates a time-varying E field that in turn exerts a force on the spins, hence the self-inductance.…”