Eur. Phys. J. D (2013) 67: 72
https://doi.org/10.1140/epjd/e2013-30346-9

Regular Article

Reexamining Larmor precession in a spin-rotator: testable correction and its ramifications

¹ CAPSS, Department of Physics, Bose Institute, Salt Lake, 700091 Kolkata, India
² LPTM (CNRS Unité 8089), Université de Cergy-Pontoise, 95302 Cergy-Pontoise Cedex, France
³ Graduate School of Information Science, Nagoya University, Chikusa-ku, 464-8601 Nagoya, Japan
⁴ Tata Institute of Fundamental Research, Homi Bhabha Road, 400005 Mumbai, India

^a e-mail: dhome@bosemain.boseinst.ac.in
^b e-mail: akp@math.cm.is.nagoya-u.ac.jp
^c e-mail: arka@theory.tifr.res.in

Received: 30 May 2012
Received in final form: 29 December 2012
Published online: 30 April 2013

Abstract

For a spin-polarized plane wave passing through a spin-rotator containing uniform magnetic field, we provide a detailed analysis for solving the appropriate Schrödinger equation. A modified expression for spin precession is obtained which reduces to the standard Larmor precession relation when kinetic energy is very large compared to the spin-magnetic field interaction. We show that there are experimentally verifiable regimes of departure from the standard Larmor precession formula. The treatment is then extended to the case of a spin-polarized wave packet passing through a uniform magnetic field. The results based on the standard expression for Larmor precession and that obtained from the modified formula are compared in various regimes of the experimental parameters.