Publications
2024
Restoring the fluctuation-dissipation theorem in Kardar-Parisi-Zhang universality class through a new emergent fractal dimension
Márcio S. Gomes-Filho, Pablo de Castro, Danilo B. Liarte, Fernando. A. Oliveira
Entropy 2024, Volume 26, Issue 3, 260
Movement bias in asymmetric landscapes and its impact on population distribution and critical habitat size
Vivian Dornelas, Pablo de Castro, Justin M. Calabrese, William F. Fagan, Ricardo Martinez-Garcia
arXiv:2306.06450 (Submitted)
2023
Mixtures of self-propelled particles interacting with asymmetric obstacles
Mauricio Rojas-Vega, Pablo de Castro, and Rodrigo Soto
The European Physical Journal E 46, 95
Sequential epidemic spread between agglomerates of self-propelled agents in one dimension
Physical Review E 108, 044104
Wetting dynamics by mixtures of fast and slow self-propelled particles
Mauricio Rojas-Vega, Pablo de Castro, and Rodrigo Soto
Physical Review E 107, 014608
2022
Spinning rigid bodies driven by orbital forcing: The role of dry friction
Pablo de Castro, Tiago Araújo Lima, and Fernando Parisio
Nonlinear Dynamics, 2022, 107, 3473–3484
2021
Diversity of self-propulsion speeds reduces motility-induced clustering in confined active matter
Pablo de Castro, Francisco M. Rocha, Saulo Diles, Rodrigo Soto, and Peter Sollich
Soft Matter, 2021, 17, 9926-9936
Active mixtures in a narrow channel: Motility diversity changes cluster sizes
Pablo de Castro, Saulo Diles, Rodrigo Soto, and Peter Sollich
Soft Matter, 2021, 17, 2050 - 2061
2020
Run-and-tumble bacteria slowly approaching the diffusive regime
Andrea Villa-Torrealba, Cristóbal Chávez-Raby, Pablo de Castro, and Rodrigo Soto
Physical Review E 101, 062607
2019
Phase separation of mixtures after a second quench: composition heterogeneities
Pablo de Castro and Peter Sollich
Soft Matter, 2019, 15, 9287 - 9299
Phase separation of polydisperse fluids
Pablo de Castro
King's College London (PhD thesis)
2018
Critical phase behavior in multi-component fluid mixtures: Complete scaling analysis
Pablo de Castro and Peter Sollich
The Journal of Chemical Physics 149 (20), 204902
2017
Phase separation dynamics of polydisperse colloids: a mean-field lattice-gas theory
Pablo de Castro and Peter Sollich
Physical Chemistry Chemical Physics 19 (33), 22509-22527
2014
Role of viscous friction in the reverse rotation of a disk
Pablo de Castro and Fernando Parisio
Physical Review E 90 (1), 013201
Efeitos de atrito na rotação reversa de corpos rígidos circularmente forçados
Pablo de Castro
Universidade Federal de Pernambuco (MSc dissertation)
Restoring the fluctuation-dissipation theorem in Kardar-Parisi-Zhang universality class through a new emergent fractal dimension
Márcio S. Gomes-Filho, Pablo de Castro, Danilo B. Liarte, Fernando. A. Oliveira
Entropy 2024, Volume 26, Issue 3, 260
Movement bias in asymmetric landscapes and its impact on population distribution and critical habitat size
Vivian Dornelas, Pablo de Castro, Justin M. Calabrese, William F. Fagan, Ricardo Martinez-Garcia
arXiv:2306.06450 (Submitted)
2023
Mixtures of self-propelled particles interacting with asymmetric obstacles
Mauricio Rojas-Vega, Pablo de Castro, and Rodrigo Soto
The European Physical Journal E 46, 95
Sequential epidemic spread between agglomerates of self-propelled agents in one dimension
Physical Review E 108, 044104
Wetting dynamics by mixtures of fast and slow self-propelled particles
Mauricio Rojas-Vega, Pablo de Castro, and Rodrigo Soto
Physical Review E 107, 014608
2022
Spinning rigid bodies driven by orbital forcing: The role of dry friction
Pablo de Castro, Tiago Araújo Lima, and Fernando Parisio
Nonlinear Dynamics, 2022, 107, 3473–3484
2021
Diversity of self-propulsion speeds reduces motility-induced clustering in confined active matter
Pablo de Castro, Francisco M. Rocha, Saulo Diles, Rodrigo Soto, and Peter Sollich
Soft Matter, 2021, 17, 9926-9936
Active mixtures in a narrow channel: Motility diversity changes cluster sizes
Pablo de Castro, Saulo Diles, Rodrigo Soto, and Peter Sollich
Soft Matter, 2021, 17, 2050 - 2061
2020
Run-and-tumble bacteria slowly approaching the diffusive regime
Andrea Villa-Torrealba, Cristóbal Chávez-Raby, Pablo de Castro, and Rodrigo Soto
Physical Review E 101, 062607
2019
Phase separation of mixtures after a second quench: composition heterogeneities
Pablo de Castro and Peter Sollich
Soft Matter, 2019, 15, 9287 - 9299
Phase separation of polydisperse fluids
Pablo de Castro
King's College London (PhD thesis)
2018
Critical phase behavior in multi-component fluid mixtures: Complete scaling analysis
Pablo de Castro and Peter Sollich
The Journal of Chemical Physics 149 (20), 204902
2017
Phase separation dynamics of polydisperse colloids: a mean-field lattice-gas theory
Pablo de Castro and Peter Sollich
Physical Chemistry Chemical Physics 19 (33), 22509-22527
2014
Role of viscous friction in the reverse rotation of a disk
Pablo de Castro and Fernando Parisio
Physical Review E 90 (1), 013201
Efeitos de atrito na rotação reversa de corpos rígidos circularmente forçados
Pablo de Castro
Universidade Federal de Pernambuco (MSc dissertation)
Mixtures of self-propelled particles
The persistent motion of bacteria produces clusters following a stationary cluster size distribution (CSD). We developed a minimal model on a quasi-1D lattice for bacteria in a narrow channel to assess the relative importance between motility diversity (i.e., polydispersity in motility parameters) and confinement. We found that motility-induced phase separation leads to clustering amplification induced by motility diversity and clustering suppression by confinement relaxation.
Bacteria slowly approaching the diffusive regime
The run-and-tumble (RT) dynamics followed by bacterial swimmers gives rise first to a ballistic motion due to their persistence and later, through consecutive tumbles, to a diffusive process. A linear time dependence of the mean-squared displacement (MSD) is insufficient to characterize diffusion and thus we also focus on the excess kurtosis of the displacement distribution. We investigated bacteria with four swimming strategies are considered and found in which cases that the relaxation to diffusion can take much longer than the mean time between tumble events, evidencing the existence of large tails in the particle displacements.
Phase separation dynamics of dense mixtures
The constituent particles of soft matter systems typically exhibit variation in terms of some attribute such as their size, charge, etc. Examples of these so-called “polydisperse” systems are everywhere, including colloids, liquid crystals, and polymers. Understanding the physical consequences of polydispersity, however, is a considerable challenge. We explore qualitative aspects of polydisperse phase behaviour on two fronts. We study the dynamics of phase separation in polydisperse colloidal systems by developing, analysing, and simulating a dynamical mean-field theory for the Polydisperse Lattice-Gas (PLG) model. In particular we test effects of fractionation, where mixture components are distributed unevenly across coexisting phases. Our results provide strong theoretical evidence that, due to slow fractionation, (i) dense colloidal mixtures phase-separate in two stages and (ii) the denser phase contains long-lived composition heterogeneities. We also provide a practical method to determine whether such heterogeneities are indeed present in a given phase-separating mixture. Moreover, we study colloidal mixtures phase separating after a secondary temperature quench into the two- and three-phase coexistence regions. We found several interesting effects (mostly associated with the extent to which crowding effects can slow down composition changes), including long-lived regular arrangements of secondary domains; interrupted coarsening of primary domains; wetting of fractionated interfaces by oppositely fractionated layers; ‘surface’-directed spinodal ‘waves’ propagating from primary domain interfaces; and filamentous morphologies arising out of secondary domains.
Critical phase behaviour of fluid mixtures
We analyse the critical gas-liquid phase equilibrium behaviour of arbitrary fluid mixtures in the coexistence region, focussing on settings which are relevant for polydisperse colloids. Our analysis uses Fisher’s complete scaling formalism and thus includes ‘pressure mixing’ effects in the mapping from the fluid’s thermodynamic fields to the 3D Ising effective fields. Because of fractionation, the behaviour is remarkably rich. We give scaling laws for a number of new and conventional important loci in the phase diagram. In particular we identify new suitable observables for detecting pressure mixing effects. Our predictions are checked against numerics by using mapping parameters fitted to Lennard- Jones simulation data, allowing us to highlight crossovers where pressure mixing becomes relevant close to the critical point.
Click here to see my thesis.
Circularly driven rigid bodies
We studied the effects of dissipation to the reverse rotation phenomenon of a rigid body under both viscous and dry friction.
Click here to see my dissertation, in Portuguese.
Coastal trapped waves
I worked on physical oceanography at the Department of Oceanography at UFPE analysing observational data of "coastal trapped waves" propagating alongshore the Brazilian coast.
The persistent motion of bacteria produces clusters following a stationary cluster size distribution (CSD). We developed a minimal model on a quasi-1D lattice for bacteria in a narrow channel to assess the relative importance between motility diversity (i.e., polydispersity in motility parameters) and confinement. We found that motility-induced phase separation leads to clustering amplification induced by motility diversity and clustering suppression by confinement relaxation.
Bacteria slowly approaching the diffusive regime
The run-and-tumble (RT) dynamics followed by bacterial swimmers gives rise first to a ballistic motion due to their persistence and later, through consecutive tumbles, to a diffusive process. A linear time dependence of the mean-squared displacement (MSD) is insufficient to characterize diffusion and thus we also focus on the excess kurtosis of the displacement distribution. We investigated bacteria with four swimming strategies are considered and found in which cases that the relaxation to diffusion can take much longer than the mean time between tumble events, evidencing the existence of large tails in the particle displacements.
Phase separation dynamics of dense mixtures
The constituent particles of soft matter systems typically exhibit variation in terms of some attribute such as their size, charge, etc. Examples of these so-called “polydisperse” systems are everywhere, including colloids, liquid crystals, and polymers. Understanding the physical consequences of polydispersity, however, is a considerable challenge. We explore qualitative aspects of polydisperse phase behaviour on two fronts. We study the dynamics of phase separation in polydisperse colloidal systems by developing, analysing, and simulating a dynamical mean-field theory for the Polydisperse Lattice-Gas (PLG) model. In particular we test effects of fractionation, where mixture components are distributed unevenly across coexisting phases. Our results provide strong theoretical evidence that, due to slow fractionation, (i) dense colloidal mixtures phase-separate in two stages and (ii) the denser phase contains long-lived composition heterogeneities. We also provide a practical method to determine whether such heterogeneities are indeed present in a given phase-separating mixture. Moreover, we study colloidal mixtures phase separating after a secondary temperature quench into the two- and three-phase coexistence regions. We found several interesting effects (mostly associated with the extent to which crowding effects can slow down composition changes), including long-lived regular arrangements of secondary domains; interrupted coarsening of primary domains; wetting of fractionated interfaces by oppositely fractionated layers; ‘surface’-directed spinodal ‘waves’ propagating from primary domain interfaces; and filamentous morphologies arising out of secondary domains.
Critical phase behaviour of fluid mixtures
We analyse the critical gas-liquid phase equilibrium behaviour of arbitrary fluid mixtures in the coexistence region, focussing on settings which are relevant for polydisperse colloids. Our analysis uses Fisher’s complete scaling formalism and thus includes ‘pressure mixing’ effects in the mapping from the fluid’s thermodynamic fields to the 3D Ising effective fields. Because of fractionation, the behaviour is remarkably rich. We give scaling laws for a number of new and conventional important loci in the phase diagram. In particular we identify new suitable observables for detecting pressure mixing effects. Our predictions are checked against numerics by using mapping parameters fitted to Lennard- Jones simulation data, allowing us to highlight crossovers where pressure mixing becomes relevant close to the critical point.
Click here to see my thesis.
Circularly driven rigid bodies
We studied the effects of dissipation to the reverse rotation phenomenon of a rigid body under both viscous and dry friction.
Click here to see my dissertation, in Portuguese.
Coastal trapped waves
I worked on physical oceanography at the Department of Oceanography at UFPE analysing observational data of "coastal trapped waves" propagating alongshore the Brazilian coast.
Poster on Phase-separating mixtures: Slow composition relaxation | |
File Size: | 972 kb |
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Audio for the above poster | |
File Size: | 4509 kb |
File Type: | mp3 |
Wetting dynamics by mixtures of fast and slow self-propelled particles
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