# Non-Reversibility of Molecular Dynamics Trajectories

## TL;DR

This paper investigates the causes of non-reversibility in molecular dynamics trajectories, showing that rounding errors lead to irreversibility but do not significantly impact Hybrid Monte Carlo methods, supported by data from gauge theories.

## Contribution

It provides an analysis of rounding error amplification in molecular dynamics and argues that non-reversibility is not a major concern for Hybrid Monte Carlo simulations.

## Key findings

- Rounding errors cause non-reversibility in trajectories.
- Non-reversibility does not significantly affect Hybrid Monte Carlo.
- Data from SU(3) gauge theory and QCD supports the analysis.

## Abstract

We study the non-reversibility of molecular dynamics trajectories arising from the amplification of rounding errors. We analyse the causes of such behaviour and give arguments, indicating that this does not pose a significant problem for Hybrid Monte Carlo computations. We present data for pure SU(3) gauge theory and for QCD with dynamical fermions on small lattices to illustrate and to support some of our ideas.