Banca de QUALIFICAÇÃO: LUCAS GABRIEL BEZERRA DE SOUZA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUCAS GABRIEL BEZERRA DE SOUZA
DATE: 03/04/2025
TIME: 09:00
LOCAL: Plataforma Google Meet
TITLE:

Active particles interacting via chemical and mechanical motility regulation

KEY WORDS:

Active matter, biological physics, quorum-sensing, steric interactions, phase behavior

PAGES: 49
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

Many organisms, such as bacteria, cells, and insects, exemplify components of active systems. One communication strategy
they adopt is chemically sensing others' presence, a process known as quorum sensing. This mechanism regulates motility to
achieve beneficial conditions, such as foraging and protection, by controlling spatial distribution. However, their motion can be
constrained by mechanical interactions, including physical size or shape. This may lead to particle accumulation, where
persistent motion and chemical interactions reduce their effective speed, generating diverse spatiotemporal patterns. We
investigate the aggregation behavior of active particles interacting via short-range steric repulsion and quorum-sensing motility
regulation, where self-propulsion speed decreases with increasing local density.
Through simulations and theoretical modeling, we reveal two reentrant phase behaviors: one driven by persistence and the
other by quorum-sensing sensitivity. Reentrance arises from the competition between effective attraction, induced by quorum
sensing, and persistent motion. Building on a kinetic theory describing the fraction of particles in aggregates, we elucidate the
physical origins of these reentrant behaviors. Additionally, we identify distinct phase separation kinetics, ranging from
nucleation and growth to active gel coarsening.

 

COMMITTEE MEMBERS:
Externo à Instituição - PABLO SOUZA DE CASTRO MELO - UNESP
Interno - 1379465 - GILBERTO CORSO
Presidente - 1294916 - MADRAS VISWANATHAN GANDHI MOHAN
Interno - 1672854 - RAIMUNDO SILVA JUNIOR