Stable interactions via proper deformations

TL;DR

This paper introduces a novel method for implementing stable interactions in physical theories that preserve symmetries and conservation laws, demonstrated through applications to higher-derivative systems like the Pais-Uhlenbeck oscillator.

Contribution

The paper presents a new approach for constructing stable, symmetry-compatible interactions in both Lagrangian and non-Lagrangian theories with higher derivatives.

Findings

Constructed a wide class of stable interactions for the Pais-Uhlenbeck oscillator.

Demonstrated the method's compatibility with global symmetries and conservation laws.

Provided a framework applicable to both Lagrangian and non-Lagrangian higher-derivative theories.

Abstract

A new method is proposed for switching on interactions that are compatible with global symmetries and conservation laws of the original free theory. The method is applied to the control of stability in Lagrangian and non-Lagrangian theories with higher derivatives. By way of illustration, a wide class of stable interactions is constructed for the Pais-Uhlenbeck oscillator.