# Torsion effects on Condensed Matter: like a magnetic field but not so much

## TL;DR

This paper investigates how torsion from topological defects in elastic solids influences particle dynamics, revealing analogies to magnetic fields and novel spin interactions that could enable magnetic-field-free spin resonance experiments.

## Contribution

It introduces the concept of torsion effects mimicking magnetic fields in condensed matter, including the presence of analogue Landau levels and spin-torsion coupling effects.

## Key findings

- Analogue Landau levels exist but are not confined to two dimensions.
- Zero modes appear for quantized momentum values in spinless carriers.
- Spin carriers experience a Zeeman-like coupling with torsion, independent of charge.

## Abstract

In this work, we study the effects of torsion due to a uniform distribution of topological defects (screw dislocations) on free spin/carrier dynamics in elastic solids. When a particle moves in such a medium, the effect of the torsion associated to the defect distribution is analogous to that of an applied magnetic field but with subtle differences. Analogue Landau levels are present in this system but they cannot be confined to two dimensions. In the case of spinless carriers, zero modes, which do not appear in the magnetic Landau levels, show up for quantized values of the linear momentum projected on the defects axis. Particles with spin are subjected to a Zeeman-like coupling between spin and torsion, which is insensitive to charge. This suggests the possibility of spin resonance experiments without a magnetic field for charged carriers or quasiparticles without electrical charge, like triplet excitons, for instance.