Contributor info: Prof. Mauricio Valenzuela

Mauricio Valenzuela, Jorge Zanelli

SciPost Phys. 16, 065 (2024) · published 4 March 2024 | Toggle abstract · pdf

Counting the degrees of freedom of the massless Rarita-Schwinger theory is revisited using Behrends-Fronsdal projectors. The identification of the gauge invariant part of the vector-spinor is thus straightforward, consisting of spins 1/2 and 3/2. The validity of this statement is supported by the explicit solution found in the standard gamma-traceless gauge. Since the obtained systems are deterministic -free of arbitrary functions of time- we argue that the often-invoked residual gauge symmetry lacks fundamental grounding and should not be used to enforce new external constraints. The result is verified by the total Hamiltonian dynamics. We conclude that eliminating the spin-1/2 mode via the extended Hamiltonian dynamics would be acceptable if the Dirac conjecture was assumed; however, this framework does not accurately describe the original Lagrangian system.

Mauricio Valenzuela, Jorge Zanelli

SciPost Phys. Proc. 14, 047 (2023) · published 24 November 2023 | Toggle abstract · pdf

We analyze the Rarita-Schwinger massless theory in the Lagrangian and Hamiltonian approaches. At the Lagrangian level, the standard gamma-trace gauge fixing constraint leaves a 1/2 and a 3/2 propagating Poincaré group helicities. At the Hamiltonian level, the result depends on whether the Dirac conjecture is assumed or not. In the affirmative case, a secondary first class constraint is added to the total Hamiltonian and a corresponding gauge fixing condition must be imposed, completely removing the 1/2 sector. In the opposite case, the 1/2 field propagates and the Hamilton field equations match the Euler-Lagrange equations.

Rutwig Campoamor-Stursberg, Marc de Montigny, Michel Rausch de Traubenberg, Mauricio Valenzuela

SciPost Phys. Proc. 14, 001 (2023) · published 23 November 2023 | Toggle abstract · pdf

Introduction to the proceedings of the 34th International Colloquium on Group Theoretical Methods in Physics.