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Active colloids self-organize to form a polar-ordered flock which propagates through a microfluidic channel. Video is real time. Channel width is 1 mm.
- Journées de la Matière Condensée, oral presentation, (Grenoble, France 2018).
- Gordon Research Conference - Soft Condensed Matter Physics, poster presentation, (New London, NH, USA 2017).
- Liquids 2017 - 10th Liquid Matter Conference, oral presentation, (Ljubljana, Slovenia 2017).
- Laboratoire International Associé - Matière : Structure et Dynamique, invited oral presentation, (Lyon, France 2017).
- APS March Meeting, oral presentation, (New Orleans, LA, USA 2017).
- Patterns in Nature – Functions, Variations and Control, oral presentation, (Bayreuth, Germany 2016).
- StatPhys 26, poster presentation, Poster award, (Lyon, France 2016).
- Active and smart matter, poster presentation, (Syracuse, NY, USA 2016).
Flowing active liquids in a pipe: Hysteretic response of polar flocks to external fields,
Alexandre Morin and Denis Bartolo,
Phys. Rev. X 8, 021037,
Spontaneously flowing liquids have been successfully engineered from a variety of biological and synthetic self-propelled units. Together with their orientational order, wave propagation in such active fluids have remained a subject of intense theoretical studies for more than two decades. Until now, this phenomenon has however never been experimentally observed. Here, we establish and exploit the propagation of sound waves in colloidal active materials with broken rotational symmetry. We show that two mixed modes coupling density and velocity fluctuations propagate along all directions in colloidal-roller fluids. We then show how the six materials constants defining the linear hydrodynamics of these active liquids can be measured from their spontaneous fluctuation spectrum, while being out of reach of conventional rheological methods. This active-sound spectroscopy is not specific to synthetic active materials and could provide a quantitative hydrodynamic description of herds, flocks and swarms from inspection of their large-scale fluctuationsHighlighted by:
- Diffusion, subdiffusion, and localization of active colloids in random post lattices, Alexandre Morin, David Lopes Cardozo, Vijayakumar Chikkadi, and Denis Bartolo, Phys. Rev. E 91, 042611,
- Distortion and destruction of colloidal flocks in disordered environments, Alexandre Morin, Nicolas Desreumaux, Jean-Baptiste Caussin, and Denis Bartolo, Nature Physics,
- Collective motion with anticipation: Flocking, spinning, and swarming, Alexandre Morin, Jean-Baptiste Caussin, Christophe Eloy, and Denis Bartolo, Phys. Rev. E 91, 012134,