• active colloids
• active matter
• Brownian motion
• collective behaviors
• collective motion
• inference
• phase transitions
• polarization
• radial distribution function
• simulation

Active Matter is a term that refers to systems, both at macroscopic and microscopic scales, both natural and artificial, that consist of many independent and interacting agents. These active units can consume energy from the environment or an internal source to convert it to work and movement. Such systems show peculiar individual and collective behaviors, due to the interactions that may occur between active units and to their intrinsic far-from-equilibrium nature. Self-phoretic Janus micro-particles are a class of active particles that convert chemical energy into self-propulsion, creating a gradient in the surrounding fluid that makes them move with a preferred direction. These particles are a model system for active matter, and they have been used to study collective behaviors. They have been modelled as Active Brownian Particles (ABPs), adding a deterministic self-propulsion along a given direction to classic Brownian motion. The ABPs model stood out for its simplicity and capability of showing interesting collective dynamics. Literature has studied what happens when interactions are added to this model, such as excluded-volume interaction, which avoids superpositions between particles, and long-range central potentials interactions. The objective of this thesis work is to build a minimal yet descriptive model, a simulation framework and a set of analysis tools to investigate the emergence of different collective behaviors in active particles systems.