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Caporusso CB, Gonnella G, Levis D. Phase Coexistence and Edge Currents in the Chiral Lennard-Jones Fluid. PHYSICAL REVIEW LETTERS 2024; 132:168201. [PMID: 38701478 DOI: 10.1103/physrevlett.132.168201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 10/21/2023] [Accepted: 03/15/2024] [Indexed: 05/05/2024]
Abstract
We study a model chiral fluid in two dimensions composed of Brownian disks interacting via a Lennard-Jones potential and a nonconservative transverse force, mimicking colloids spinning at a given rate. The system exhibits a phase separation between a chiral liquid and a dilute gas phase that can be characterized using a thermodynamic framework. We compute the equations of state and show that the surface tension controls interface corrections to the coexisting pressure predicted from the equal-area construction. Transverse forces increase surface tension and generate edge currents at the liquid-gas interface. The analysis of these currents shows that the rotational viscosity introduced in chiral hydrodynamics is consistent with microscopic bulk mechanical measurements. Chirality can also break the solid phase, giving rise to a dense fluid made of rotating hexatic patches. Our Letter paves the way for the development of the statistical mechanics of chiral particles assemblies.
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Affiliation(s)
- Claudio B Caporusso
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari and INFN Sezione di Bari, via Amendola 173 Bari 70126 Italy
| | - Giuseppe Gonnella
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari and INFN Sezione di Bari, via Amendola 173 Bari 70126 Italy
| | - Demian Levis
- Departament de Física de la Matèria Condensada, Universitat de Barcelona C. Martí Franquès, 1 08028 Barcelona Spain
- UBICS University of Barcelona Institute of Complex Systems Martí i Franquès, 1 E08028 Barcelona Spain
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Yonezu Y, Inaba K, Yamada Y, Ikuta T, Inagaki T, Honjo T, Takesue H. 10-GHz-clock time-multiplexed non-degenerate optical parametric oscillator network with a variable planar lightwave circuit interferometer. OPTICS LETTERS 2023; 48:5787-5790. [PMID: 37910759 DOI: 10.1364/ol.499993] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 10/06/2023] [Indexed: 11/03/2023]
Abstract
A coherent XY machine (CXYM) is a physical spin simulator that can simulate the XY model by mapping XY spins onto the continuous phases of non-degenerate optical parametric oscillators (NOPOs). Here, we demonstrated a large-scale CXYM with >47,000 spins by generating 10-GHz-clock time-multiplexed NOPO pulses via four-wave mixing in a highly nonlinear fiber inside a fiber ring cavity. By implementing a unidirectional coupling from the ith pulse to the (i + 1)th pulse with a variable 1-pulse delay planar lightwave circuit interferometer, we successfully controlled the effective temperature of a one-dimensional XY spin network within two orders of magnitude.
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Haldar A, Sarkar A, Chatterjee S, Basu A. Active XY model on a substrate: Density fluctuations and phase ordering. Phys Rev E 2023; 108:034114. [PMID: 37849142 DOI: 10.1103/physreve.108.034114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 06/13/2023] [Indexed: 10/19/2023]
Abstract
We explore the generic long-wavelength properties of an active XY model on a substrate, consisting of a collection of nearly phase-ordered active XY spins in contact with a diffusing, conserved species, as a representative system of active spinners with a conservation law. The spins rotate actively in response to the local density fluctuations and local phase differences, on a solid substrate. We investigate this system by Monte Carlo simulations of an agent-based model, which we set up, complemented by the hydrodynamic theory for the system. We demonstrate that this system can phase-synchronize without any hydrodynamic interactions. Our combined numerical and analytical studies show that this model, when stable, displays hitherto unstudied scaling behavior: As a consequence of the interplay between the mobility, active rotation, and number conservation, such a system can be stable over a wide range of the model parameters characterized by a novel correspondence between the phase and density fluctuations. In different regions of the phase space where the phase-ordered system is stable, it displays generalized quasi-long-range order (QLRO): It shows phase ordering which is generically either logarithmically stronger than the conventional QLRO found in its equilibrium limit, together with "miniscule number fluctuations," or logarithmically weaker than QLRO along with "giant number fluctuations," showing a novel one-to-one correspondence between phase ordering and density fluctuations in the ordered states. Intriguingly, these scaling exponents are found to depend explicitly on the model parameters. We further show that in other parameter regimes there are no stable, ordered phases. Instead, two distinct types of disordered states with short-range phase order are found, characterized by the presence or absence of stable clusters of finite sizes. In a surprising connection, the hydrodynamic theory for this model also describes the fluctuations in a Kardar-Parisi-Zhang (KPZ) surface with a conserved species on it, or an active fluid membrane with a finite tension, without momentum conservation and a conserved species living on it. This implies the existence of stable fluctuating surfaces that are only logarithmically smoother or rougher than the Edward-Wilkinson surface at two dimensions (2D) can exist, in contrast to the 2D pure KPZ-like "rough" surfaces.
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Affiliation(s)
- Astik Haldar
- Theory Division, Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, 1/AF Bidhannagar, Calcutta 700064, West Bengal, India
| | - Apurba Sarkar
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Kolkata-700032, West Bengal, India
| | - Swarnajit Chatterjee
- Center for Biophysics & Department for Theoretical Physics, Saarland University, 66123 Saarbrücken, Germany
| | - Abhik Basu
- Theory Division, Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, 1/AF Bidhannagar, Calcutta 700064, West Bengal, India
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Kumar N, Zhang R, Redford SA, de Pablo JJ, Gardel ML. Catapulting of topological defects through elasticity bands in active nematics. SOFT MATTER 2022; 18:5271-5281. [PMID: 35789364 DOI: 10.1039/d2sm00414c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Active materials are those in which individual, uncoordinated local stresses drive the material out of equilibrium on a global scale. Examples of such assemblies can be seen across scales from schools of fish to the cellular cytoskeleton and underpin many important biological processes. Synthetic experiments that recapitulate the essential features of such active systems have been the object of study for decades as their simple rules allow us to elucidate the physical underpinnings of collective motion. One system of particular interest has been active nematic liquid crystals (LCs). Because of their well understood passive physics, LCs provide a rich platform to interrogate the effects of active stress. The flows and steady state structures that emerge in an active LCs have been understood to result from a competition between nematic elasticity and the local activity. However most investigations of such phenomena consider only the magnitude of the elastic resistance and not its peculiarities. Here we investigate a nematic liquid crystal and selectively change the ratio of the material's splay and bend elasticities. We show that increases in the nematic's bend elasticity specifically drives the material into an exotic steady state where elongated regions of acute bend distortion or "elasticity bands" dominate the structure and dynamics. We show that these bands strongly influence defect dynamics, including the rapid motion or "catapulting" along the disintegration of one of these bands thus converting bend distortion into defect transport. Thus, we report a novel dynamical state resultant from the competition between nematic elasticity and active stress.
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Affiliation(s)
- Nitin Kumar
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
- Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, India
| | - Rui Zhang
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
| | - Steven A Redford
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
- Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, Illinois 60637, USA
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
- Institute for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Margaret L Gardel
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
- Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
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Digregorio P, Levis D, Cugliandolo LF, Gonnella G, Pagonabarraga I. Unified analysis of topological defects in 2D systems of active and passive disks. SOFT MATTER 2022; 18:566-591. [PMID: 34928290 DOI: 10.1039/d1sm01411k] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We provide a comprehensive quantitative analysis of localized and extended topological defects in the steady state of 2D passive and active repulsive Brownian disk systems. We show that, both in and out-of-equilibrium, the passage from the solid to the hexatic is driven by the unbinding of dislocations, in quantitative agreement with the KTHNY singularity. Instead, extended clusters of defects largely dominate below the solid-hexatic critical line. The latter percolate in the liquid phase very close to the hexatic-liquid transition, both for continuous and discontinuous transitions, in the homogeneous liquid regime. At critical percolation the clusters of defects are fractal with statistical and geometric properties that are independent of the activity and compatible with the universality class of uncorrelated critical percolation. We also characterize the spatial organization of point-like defects and we show that the disclinations are not free, but rather always very near more complex defect structures. At high activity, the bulk of the dense phase generated by Motility-Induced Phase Separation is characterized by a density of point-like defects, and statistics and morphology of defect clusters, set by the amount of activity and not the packing fraction. Hexatic domains within the dense phase are separated by grain-boundaries along which a finite network of topological defects resides, interrupted by gas bubbles in cavitation. This structure is dynamic in the sense that the defect network allows for an unzipping mechanism that leaves free space for gas bubbles to appear, close, and even be released into the dilute phase.
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Affiliation(s)
- Pasquale Digregorio
- Centre Européen de Calcul Atomique et Moléculaire (CECAM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochimie, Avenue Forel 2, 1015 Lausanne, Switzerland
| | - Demian Levis
- Departament de Fisica de la Materia Condensada, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona, Spain
- UBICS University of Barcelona Institute of Complex Systems, Martí i Franquès 1, E08028 Barcelona, Spain
| | - Leticia F Cugliandolo
- Laboratoire de Physique Théorique et Hautes Energies, Sorbonne Université, CNRS UMR 7589, 4 Place Jussieu, 75252 Paris Cedex 05, France
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris Cedex 05, France
| | - Giuseppe Gonnella
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - Ignacio Pagonabarraga
- Centre Européen de Calcul Atomique et Moléculaire (CECAM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochimie, Avenue Forel 2, 1015 Lausanne, Switzerland
- Departament de Fisica de la Materia Condensada, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona, Spain
- UBICS University of Barcelona Institute of Complex Systems, Martí i Franquès 1, E08028 Barcelona, Spain
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Solovev A, Friedrich BM. Synchronization in cilia carpets and the Kuramoto model with local coupling: Breakup of global synchronization in the presence of noise. CHAOS (WOODBURY, N.Y.) 2022; 32:013124. [PMID: 35105113 DOI: 10.1063/5.0075095] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
Carpets of beating cilia represent a paradigmatic example of self-organized synchronization of noisy biological oscillators, characterized by traveling waves of cilia phase. We present a multi-scale model of a cilia carpet that comprises realistic hydrodynamic interactions between cilia computed for a chiral cilia beat pattern from unicellular Paramecium and active noise of the cilia beat. We demonstrate an abrupt loss of global synchronization beyond a characteristic noise strength. We characterize stochastic transitions between synchronized and disordered dynamics, which generalize the notion of phase slips in pairs of coupled noisy phase oscillators. Our theoretical work establishes a link between the two-dimensional Kuramoto model of phase oscillators with mirror-symmetric oscillator coupling and detailed models of biological oscillators with asymmetric, chiral interactions.
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Braverman L, Scheibner C, VanSaders B, Vitelli V. Topological Defects in Solids with Odd Elasticity. PHYSICAL REVIEW LETTERS 2021; 127:268001. [PMID: 35029487 DOI: 10.1103/physrevlett.127.268001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 08/31/2021] [Accepted: 11/16/2021] [Indexed: 06/14/2023]
Abstract
Crystallography typically studies collections of point particles whose interaction forces are the gradient of a potential. Lifting this assumption generically gives rise in the continuum limit to a form of elasticity with additional moduli known as odd elasticity. We show that such odd elastic moduli modify the strain induced by topological defects and their interactions, even reversing the stability of, otherwise, bound dislocation pairs. Beyond continuum theory, isolated dislocations can self propel via microscopic work cycles active at their cores that compete with conventional Peach-Koehler forces caused, for example, by an ambient torque density. We perform molecular dynamics simulations isolating active plastic processes and discuss their experimental relevance to solids composed of spinning particles, vortexlike objects, and robotic metamaterials.
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Affiliation(s)
- Lara Braverman
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Colin Scheibner
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Bryan VanSaders
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Vincenzo Vitelli
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
- Kadanoff Center for Theoretical Physics, The University of Chicago, Chicago, Illinois 60637, USA
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