Next seminar : Séminaire du LPTMS : Alexis Poncet (ENS Lyon)

Tuesday, November 29 2022 at 11:00:00

Collective effects in driven matter: from one-dimensional crowding to 2D melting

Alexis Poncet (ENS Lyon)

Hybrid: onsite seminar + zoom. Register in advance for this meeting: After registering, you will receive a confirmation email containing information about joining the meeting. The theoretical description of the structure and dynamics of matter far from thermal equilibrium is at the heart of modern statistical physics. In this seminar, I will focus on two prototypical exemples of interacting agents driven out of equilibrium: driven hard-core particles confined in 1D geometries, and 2D colloidal crystals whose the elementary units are activated, either by torques or forces. The first exemple will be discussed from a fundamental perspective combining analytical theory and extensive numerical simulations, the second exemple will be discussed combing experiments, simulations and theory. In the first part of my talk I will address some fundamental questions about the response of non-equilibrium matter to point forces far beyond linear response theory. To tackle this challenge, I will focus on the dynamic response of single-file systems locally driven by intruders. While at high density intruders can only follow one another, at low density they can unbind and separate. To explain this unbinding transition [1], I will introduce a hydrodynamic description of the density field. Strikingly, such an approach can be extended to all orders of displacement-density correlations [2], proving a complete characterization of the one-tag process in single-file lattices closely related to their integrability. In the second part of my talk, I will describe two seemingly unrelated experiments where spinning particles [3] and confined emulsions form highly dynamical polycrystals kneaded by the constant reconfigurations of grains boundaries. I will show that in both cases the lively dynamics of the crystal originate from hydrodynamic interactions that violate Newton's third law. I will investigate the impact of non-reciprocity on stabilized crystalline phases [4]. In particular I will show that non-reciprocal interactions propel the topological defects of crystals thereby suppressing long-range order and giving rise to intrinsically dynamical polycrystalline phases. [1] Bénichou, Démery & Poncet; Phys. Rev. Lett. 120, 070601 (2018) [2] Poncet, Grabsch, Illien & Bénichou; Phys. Rev. Lett. 127, 220601 (2021) [3] Bililign, Usabiaga, Ganan, Poncet, Soni, Magkiriadou, Shelley, Bartolo & Irvine; Nat. Phys. 18, 212–218 (2021) [4] Poncet & Bartolo; Phys. Rev. Lett. 128, 048002 (2022)

Last Highlight : The Journal of Physics A 2022 awards

The Journal of Physics A: Mathematical and Theoretical announced its 2022 awards.

The Early Career Researcher Best Paper Prize is awarded to Valentina Ros.

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