Seminar by G. Volpe at Tel Aviv University, 6 Mar 2019

Emergent Complex Behaviour in Active Matter
Giovanni Volpe
Light Matter Interaction Center, Tel Aviv University, Israel
6 March 2019

After a brief introduction of active particles, I’ll present some recent advances on the study of active particles in complex and crowded environments.
First, I’ll show that active particles can work as microswimmers and microengines powered by critical fluctuations and controlled by light.
Then, I’ll discuss some examples of behavior of active particles in crowded environments: a few active particles alter the overall dynamics of a system; active particles create metastable clusters and channels; active matter leads to non-Boltzmann distributions and alternative non-equilibrium relations; and active colloidal molecules can be created and controlled by light.
Finally, I’ll present some examples of the behavior of active particles in complex environments: active particles often perform 2D active Brownian motion; active particles at liquid-liquid interfaces behave as active interstitials or as active atoms; and the environment alters the optimal search strategy for active particles in complex topologies.

Seminar by G. Volpe at UNAM, Mexico City, 18 Feb 2019

Optical Tweezers: From critical fluctuations to nanoscopic force measurement
Seminar at Sistemas Complejos y Física Estadística
UNAM – Universidad National de Mexico, Mexico City, Mexico
18 February 2019

I will first give a brief overview of optical trapping and optical manipulation — the invention that has earned Arthur Ashkin the 2019 Nobel Prize in Physics. Then, I will focus on some recent applications where we have used optical tweezers to characterise critical Casimir forces and to manipulate active matter. Finally, I will present a new approach to the calibration of optical forces that we have recently developed in collaboration with UNAM.

 

Colloquium by G. Volpe at ICF, Cuernavaca, 13 Feb 2019

Emergent Complex Behaviour in Active Matter
Giovanni Volpe
Colloquium at Instituto de Ciencias Físicas
Cuernavaca, Morelos, Mexico
13 February 2019

After a brief introduction of active particles, I’ll present some recent advances on the study of active particles in complex and crowded environments.
First, I’ll show that active particles can work as microswimmers and microengines powered by critical fluctuations and controlled by light.
Then, I’ll discuss some examples of behavior of active particles in crowded environments: a few active particles alter the overall dynamics of a system; active particles create metastable clusters and channels; active matter leads to non-Boltzmann distributions and alternative non-equilibrium relations; and active colloidal molecules can be created and controlled by light.
Finally, I’ll present some examples of the behavior of active particles in complex environments: active particles often perform 2D active Brownian motion; active particles at liquid-liquid interfaces behave as active interstitials or as active atoms; and the environment alters the optimal search strategy for active particles in complex topologies.

https://www.fis.unam.mx/coloquios/473/qemergent-complex-behaviour-in-active-matterq

Talk by F. Schmidt at APS March Meeting 2019, Boston, 6 Mar 2019

Light-driven Assembly of Motile Colloidal Clusters from Immotile Building Blocks
Falko Schmidt, Benno Liebchen, Hartmut Löwen & Giovanni Volpe
APS March Meeting 2019, Boston, USA
6 March 2019 at 8:36-8:48 a.m., Room 258B

Active matter, consisting of self-propelled units locally injecting energy into the system, opens new horizons for the creation of functional soft materials with designable properties. Experiencing a constant energy input, allows active matter to self-assemble into phases with a complex architecture and functionality such as living clusters which dynamically form, reshape and break-up but would be forbidden in equilibrium material by the entropy maximization (or free energy minimization) principle. The challenge to control this active self-assembly has evoked widespread efforts typically hinging on an engineering of the properties of individual motile constituents. Here, we provide a different route, where activity occurs as an emergent phenomenon only when individual building blocks bind together, in a way which we control by laser light. Using experiments and simulations of two species of immotile microspheres, we exemplify this route by creating active molecules featuring a complex array of behaviors, becoming migrators, spinners and rotators. The possibility to control the dynamics of active self-assembly via light-controllable nonreciprocal interactions will inspire new approaches to understand living matter and to design active materials.

Reference: Schmidt et al. Light-controlled Assembly of Active Colloidal Molecules arXiv:1801.06868 (2018)

Giovanni Volpe on the Panel on the 2018 Nobel Prize in Physics, Stockholm, 7 Dec 2018

Panel on the 2018 Nobel Prize in Physics
Friday, December 7, 15:00 – 18:00
Oscar Klein hall, Albanova, Roslagstullsbacken 21, Stockholm

Albanova, Stockholm’s center for Physics, Astronomy and Biotechnology cordially organizes a panel discussion about this year’s Nobel Prize in Physics, followed by a social gathering with drinks and snacks.

Panel Members:
Felix Ritort, University of Barcelona
Cord Arnold, Lunds University
Giovanni Volpe, Göteborg University
Valdas Pasiskevicius, KTH Royal Institute of Technology

Moderator:
Eva Lindroth, Stockholms University

https://www.fysik.su.se/om-oss/evenemang/the-2018-nobel-prize-in-physics-1.415146

Here is the direct videolink:
http://video.albanova.se/ALBANOVA20181207/video.mp4  (817MB)

The event web-page is at:
http://video.albanova.se/arc2018_32.html

Short course by G. Volpe at Imaging in Neurosciences, Karolinska Institute, Stockholm, 29 Nov 2018

Lectures Graph theory concepts and Hands-on practice (Graph theory) by Giovanni Volpe within the graduate course Imaging in Neuroscience: With a focus on structural MRI methods organised by Karolinska Institute.

Venue: Alfred Nobels allé 23, room 317, campus Huddinge (Flemingsberg), Stockholm

Talk by A. Callegari at LAOP, Lima, 14 Nov 2018

Active Matter Alters the Growth Dynamics of Coffee Rings
Agnese Callegari, Tugba Andaç, Pascal Weigmann, Sabareesh K. Velu, Erçag Pince, Giorgio Volpe & Giovanni Volpe
LAOP – Latin America Optics & Photonics Congress, Lima, Peru
12-15 November 2018

Abstract: We show that bacterial mobility starts playing a major role in determining the growth dynamics of the edge of drying droplets, as the droplet evaporation rate slows down.

Talk by G. Volpe at LAOP, Lima, 13 Nov 2018

Microscopic Engine Powered by Critical Demixing
Falko Schmidt, Alessandro Magazzù, Agnese Callegari, Luca Biancofiore, Frank Cichos & Giovanni Volpe
LAOP – Latin America Optics & Photonics Congress, Lima, Peru
12-15 November 2018

Abstract: An optically trapped absorbing microsphere in a sub-critical mixture rotates around the optical trap thanks to diffusiophoretic propulsion, which can be controlled by adjusting the optical power, the temperature, and the criticality of the mixture.

Tutorial by G. Volpe and A. Callegari on Optical Tweezers at LAOP, Lima, 12 Nov 2018

Optical Trapping and Optical Manipulation
Giovanni Volpe & Agnese Callegari
Tutorial at LAOP – Latin America Optics & Photonics Congress, Lima, Peru
12-15 November 2018

Description: This course will review the theoretical underpinnings of optical trapping and optical manipulation; a review of recent applications; and provide a hands-on tutorial on the use of computational methods to simulate optical trapping and the motion of optically trapped particles.

Time: 09:00 – 13:00
Location: INICTEL-UNI, Lima, Peru

Linkhttps://www.osa.org/en-us/meetings/topical_meetings/osa_latin_america_optics_photonics_conference/program/short_courses_and_tutorials_on_monday_12_november/