Notably, these can be computed exactly within our theory. We calculate the fluid velocity variance, spatial and temporal correlation functions, the fluid velocity spectrum, and the enhanced diffusivity of tracer particles. We find that correlations are suppressed by particle self-propulsion, although the mean-field behaviour is not restored even in the limit of very fast swimming. Our theory is not perturbative and is valid for any value of the micro-swimmer density below the onset of collective motion. This work constitutes a significant methodological advance and allows us to make qualitative and quantitative predictions that can be directly compared to experiments and computer simulations of micro-swimmer suspensions.'
author:
- Viktor Škultéty
- Cesare Nardini
- Joakim Stenhammar
- Davide Marenduzzo
- Alexander Morozov
bibliography:
- 'Refs.bib'
title: Swimming suppresses correlations in dilute suspensions of pusher microorganisms
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Introduction {#section:introduction}
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In recent years active systems emerged as a new state of matter with unique properties that are absent from their passive counterparts [@Ramaswamy2010; @Marchetti2013]. Such systems comprise particles that are capable of extracting energy from their environment and using it to exert forces and torques on their surroundings. The resulting self-propulsion and interactions between particles break detailed balance at the microscopic level, 