The Lorentz-Violating effects in charged particle systems

TL;DR

This work investigates Lorentz-violating effects in relativistic spin-½ particles within the SME framework by deriving a modified Dirac Hamiltonian from a CPT-odd background and computing the resulting velocity and generalized force operators. Using Ehrenfest's theorem, the quantum dynamics are connected to a classical-like equation of motion featuring an LIV-corrected force, and the formalism is applied to Penning-trap systems to assess observable signatures. The main finding is a LIV-induced shift in the cyclotron frequency, $\tilde{\omega}_c = \omega_c + \frac{g}{m}\frac{V_0 u}{d^2}$ for space-like $\mathbf{u}$ with stationary fields, which allows setting an experimental bound $gu \le 10^{-18}\ \,\mathrm{eV}^{-1}$ based on typical trap parameters and measurement precision. The results demonstrate that precision confinement devices like Penning traps are powerful probes of Lorentz symmetry, offering a concrete route to constrain SME-like LIV terms and guiding future studies in nonuniform fields and interferometric tests of fundamental symmetries.

Abstract

We investigate the relativistic dynamics of a spin half particle in the presence of a Lorentz violating background within the framework of effective field theory. A modified Dirac Hamiltonian is considered, arising from a CPT odd coupling involving the Lorentz violating gauge tensor of the Standard Model Extension (SME). The velocity and effective force operators are derived from the Heisenberg equations of motion. Using Ehrenfest s theorem and the correspondence principle, we obtain the classical limit of the dynamics and identify an effective force exhibiting a generalized Lorentz force structure. This formalism is applied to a Penning trap system, known for its high precision measurements of charged particle properties. Our analysis shows that the effective cyclotron frequency acquires a correction due to the Lorentz violating term, leading to deviations in the particle trajectory and offering a potentially observable signature of Lorentz violation in precision experiments. By comparing our results with current bounds from high precision Penning traps, we establish an upper limit on the Lorentz violating coupling, $gu\leq 10^{-18}\text{eV}^{-1}$. These results highlight the potential of relativistic effective models to probe new physics and reinforce the role of Penning traps as sensitive tools for testing Lorentz symmetry.