Origin of Spin: From Rotation Group to Noncommutative Zitterbewegung

S. V. Izmailov, E. S. Levin

Bryan Sanctuary

We show that the Zitterbewegung of the electron arises as a real internal motion when spin is treated as a classical bivector rather than as a point-fermion of the Dirac equation. In the Bivector Standard Model, physically meaningful dynamics reside in the body-fixed frame where two orthogonal internal angular momentum vectors counter-precess about a torque axis. Their rigid rotation generates a time-dependent chord whose magnitude oscillates at twice the Compton frequency, 2ωC, and whose orientation precesses at ωC. When projected into the laboratory-fixed frame, this internal rotor produces the characteristic trembling motion of the Zitterbewegung and traces a horn torus envelope without additional assumptions. The internal clock defined by this cyclic bivector motion unifies the origin of spin properties and the de Broglie modulation. It distinguishes complementary parity sectors that cannot be related by Lorentz transformations. The Zitterbewegung is therefore not an interference between positive- and negative-energy spinors, but the visible shadow of a real, energy-conserving internal rotation inherent to the bivector structure.

L. Chotorlishvili, P Zięba, Igor E. Tralle +1 more

Abstract Zitterbewegung is the exotic phenomenon associated either with relativistic electron–positron rapid oscillation or to electron–hole transitions in narrow gap semiconductors. In the present work, we enlarge the concept of Zitterbewegung and show that trembling motion may occur due to dramatic changes in the symmetry of the system. In particular, we exploit a paradigmatic model of quantum chaos, the quantum mathematical pendulum (universal Hamiltonian). The symmetry group of this system is Klein’s four-group that possesses three invariant subgroups. The energy spectrum of the system parametrically depends on the height of the potential barrier, and contains degenerate and non-degenerate areas, corresponding to the different symmetry subgroups. Change in the height of the potential barrier switches the symmetry subgroup and leads to trembling motion. We analyzed mean square fluctuations of the velocity operator and observed that trembling is enhanced in highly excited states. We observed a link between the phenomena of trembling motion and the uncertainty relations of noncommutative operators of the system.

V. I. Roginskii

Liu Ta

The motional trembling(‘zitterbewegung’)of a relativistic electron governed by Dirac equation was originally predicted by Schr¨odinger in the early days of quantum mechanics and simulated in a recent experiment with a single trapped ultracold ion.We investigate stable and instable confinements of a single trapped ion in a Paul trap under different conditions relevant to parity.Since our treatment involves neither restriction of Lamb-Dicke limit nor rotating-wave approximation,we may demonstrate different quantum dynamics of the single trapped ion in a wide range of the trapping parameters.We discuss the origin of the zitterbewegung which is relevant to the stability of the ion trapping.

Otto C. W. Kong