Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session A07: Non-reciprocity in Soft and Active Matter IFocus
|
Hide Abstracts |
Sponsoring Units: DSOFT GSNP Chair: Anton Souslov, University of Bath Room: Room 130 |
Monday, March 6, 2023 8:00AM - 8:36AM |
A07.00001: Dynamical patterns of nonreciprocally coupled conserved fields: a unifying model Invited Speaker: M Cristina Marchetti Multicomponent active systems ubiquitously exhibit non-reciprocal effective interactions between the two species that seemingly evade Newton's third law. Nonreciprocity arises at the mesoscopic level when forces are mediated by a nonequilibrium environment and generates emergent traveling and oscillating patterns. We show that coupled Cahn-Hillard equations provide a unifying model for dynamical pattern formation in non-reciprocally coupled binary systems with conserved fields. We demonstrate that a number of physical systems can be explicitly mapped to this generic form, including mixtures of active and passive Brownian particles, active poroelastic media, mass-conserving reaction-diffusion systems, and bacterial populations with mutual motility control. In all these systems mass conservation is responsible for the Goldstone mode which interacts with the non-reciprocal couplings mediating mass redistribution and driving the onset of traveling states. We identify a generic form of the dispersion relation governing the growth of linear fluctuations that provides the identifying signature for this class of nonreciprocally coupled conservation laws. Finally, the propagation speed of the traveling waves can be read-off from the dispersion relation even deep in the nonlinear regime. |
Monday, March 6, 2023 8:36AM - 8:48AM |
A07.00002: Emergence of non-reciprocal forces in optically bound colloids Dustin P Kleckner, Dominique J Davenport, Nicholas St. Clair Optical binding is a powerful tool for producing complex inter-particle forces in colloidal systems, mediated by an intense light field. This force is reciprocal for weakly scattering or symmetric configurations of particles. Experiments with large numbers of wavelength-sized particles, however, demonstrate different behavior: they spontaneously assemble clusters which exhibit driven motion. We will show these driving forces arise because the optical binding force is not pairwise: the contributions from many particle scattering gives rise to non-reciprocal forces. As a result, optically bound colloids behave like a novel active matter system where the driving forces depend on the specific configuration of particles. |
Monday, March 6, 2023 8:48AM - 9:00AM |
A07.00003: Effects of non-reciprocal forces in acoustically bound clusters Nicholas St Clair Acoustic fields can produce trapping forces on single particles, analogous to the optical trapping effect. |
Monday, March 6, 2023 9:00AM - 9:12AM |
A07.00004: Non-reciprocal interactions result in the partial demixing of binary polar fluids Alexandre Morin, Samadarshi Maity Agents or particles that spontaneously assemble into active liquids can feature non-reciprocal interactions. In this presentation, we investigate the consequences of non-reciprocity on the structure and dynamics of binary mixtures of polar liquids. We assemble colloidal polar liquids, known as Quincke-roller flocks, out of bi-disperse colloidal suspensions. Interestingly, partial demixing occurs spontaneously in the system. We first quantify this macroscopic behaviour and then search for its origin at the particle scale. Finally, we complement our experimental analysis with hydrodynamics theory. We gain insight into the spontaneous demixing process and propose a simplified description of such mixtures by pushing non-reciprocal interactions to the limit of one-way actions. Within this simplified description, one species creates an active environment which, in essence, drives the second species. Our work illustrates the possibility of exploiting non-reciprocity in active materials to achieve precise functions. |
Monday, March 6, 2023 9:12AM - 9:24AM |
A07.00005: Particle kinetics and collective dynamics in chiral gasses, fluids, and crystals Alexander P Petroff, Christopher Whittington, Arshad Kudrolli The velocity profile in an active two-dimensional chiral material---composed of centimeter-scale geared particles confined in a circular vibrating chamber---is measured for particle concentrations ranging from a dilute gas to a dense crystalline packing. In the dilute regime, the average particle velocity vanishes except within a distance of a single particle diameter of the chamber wall. At intermediate concentrations, the velocity profile develops an edge current that decays exponentially from the wall. A crystalline packing of chiral particles rotates as a solid body. These velocity profiles are well fit by a two-parameter linear model in which the transitional and rotational velocities of particles relax to match the motion of the surrounding particles. The corresponding relaxation rates increase continuously and smoothly across these phases of chiral matter and diverge at the maximum packing density. |
Monday, March 6, 2023 9:24AM - 9:36AM |
A07.00006: Floquet-Bloch topology of nonreciprocal sound transport Benjamin Kauffman, Jasper Marcum, Jayson J Paulose A traveling-wave stiffness modulation in an active metamaterial picks out a particular spacetime direction for sound waves, thereby serving as a mechanism for reciprocity breaking in acoustic transport which has been exploited in a variety of platforms [see review by Nassar et al, Nature Reviews Materials 2020]. One way to quantify the breaking of reciprocity in such systems is to measure the asymmetry in the dispersion relation upon comparing momenta of equal magnitude but opposite directions; the frequencies of waves with equal and opposite momenta are guaranteed to be equal in passive structures, but can differ in active systems with reciprocity-breaking modulation. This asymmetry, termed band tilting, has been shown to be quantized in the limit of adiabatic stiffness modulation [Nassar et al, Physical Review B 97, 014305 (2018)] using perturbative methods. Using exact Floquet-Bloch theory, we show that band tilting is in fact quantized at all modulation speeds by virtue of the topological winding of Floquet quasifrequencies on a (d+1)-dimensional torus for d-dimensional systems. We discuss consequences of this quantization for systems with flat bands. |
Monday, March 6, 2023 9:36AM - 9:48AM |
A07.00007: Non-reciprocal coupling and collective actuation in the presence of a polarization field. Paul Baconnier, Vincent Démery, Mathéo Aksil, Olivier Dauchot Active solids consist of elastically coupled out-of-equilibrium units performing work. Recently, it was shown that the microscopic non-reciprocal coupling between displacements and polar forces give rise to a wide variety of collective actuation at large scale. Such phenomena are central to deciphering the complex physics behind biological systems ranging from confined cell monolayers to dense bacterial suspensions and bio-films. Remarkably, such living systems also have the ability to respond to various types of environmental cues and can polarize towards or away from these signals, e.g. by chemotaxis or galvanotaxis. Yet, the effect of an external field on the collective dynamics of active solids remains, until today, largely unexplored. Here, we combine model experiments, numerical simulations, and theoretical analysis to reveal how an external field affects the dynamics of active elastic systems. We find that gravity is suitable to polarize our model active solids, and crucially, polarization decreases the activity threshold for collective actuation. Our findings may provide new mechanisms for oscillatory dynamics and regulation in biological tissues. |
Monday, March 6, 2023 9:48AM - 10:00AM |
A07.00008: Phase Coexistence Implications of Violating Newton's Third Law Yu-Jen Chiu, Ahmad K Omar Newton's third law, actio = reactio, is a foundational statement of classical mechanics. However, in natural and living systems, this law appears to be routinely violated as a result of the nonequilibrium environment. Here, we use computer simulations to explore the macroscopic phase behavior implications of breaking microscopic interaction reciprocity for a simple model system. We consider a binary mixture of attractive particles and introduce a parameter which is a continuous measure of the degree to which interaction reciprocity is broken. In the reciprocal limit, the species are indistinguishable and phase separate into domains with identical compositions. Increasing nonreciprocity is found to drive the system to explore a rich assortment of phases, including phases with strong compositional asymmetry and three-phase coexistence. Many of the states induced by these forces, including traveling states of crystal-fluid and liquid-gas coexistence, have no equilibrium analog. By mapping the complete phase diagram for this model system and characterizing these unique phases, our findings offer a concrete path forward towards understanding how nonreciprocity shapes the structures found in living systems and how they might be leveraged in synthetic materials. |
Monday, March 6, 2023 10:00AM - 10:12AM |
A07.00009: Non-reciprocal kinks in frustrated active metamaterials Xiaofei Guo, Jonas Veenstra, Corentin Coulais Reciprocity is a fundamental principle governing most physical systems. In recent years, large levels of non-reciprocity have been realized by breaking local spatial symmetries. Here we break local and global symmetries as the same time by combining non-reciprocity and the non-orientable topology. We use local control loops to break reciprocity at the level of interactions between robotic unit cells. The non-orientable topology is realized by global geometrical frustration, which breaks global translation symmetry. We show theoretically and experimentally that unidirectionally propagating kinks emerge in this active system. These reciprocal kinks are topological protected. Based on the non-reciprocal kinks, we build a soft robot, which has various topologically protected motions. We anticipate non-reciprocal kinks will open avenues for energy absorption and harvesting, soft robotics, wave propagations and topological metamaterials. |
Monday, March 6, 2023 10:12AM - 10:24AM |
A07.00010: Nonreciprocal phase transition in swarming C.elegans Askin Kocabas Nonreciprocity is a very generic phenomenon in biological systems. However, it is still not clear how these types of interactions drive the collective behaviors of active biological systems including swarming animals. In this study, we investigated the emerging response of active C.elegans aggregates and passive bacterial mixture. We experimentally observed the nonreciprocal phase transition controlling the social feeding behavior of these animals. We further found that during this transition, Parity-Time symmetry-breaking process promotes the collective chemotaxis behavior of swarming animals. Finally, we speculate that this process has an evolutionary significance that promotes the survival of social animals in nature. |
Monday, March 6, 2023 10:24AM - 10:36AM |
A07.00011: Non-reciprocal forces and exceptional phase transitions in metric and topological flocks Charles R Packard, Daniel M Sussman The Vicsek model is a cornerstone in the field of active matter and has been the basis for many other models of flocking involving alignment rules based on the mean orientation of neighboring particles. Yet, the implications of an implicit violation of Newton's third law in the alignment rule remains poorly understood. Here we show that in the absence of this microscopic non-reciprocity an exceptional phase transition is predicted at low noise strength within the Toner-Tu framework of polar aligning matter; we demonstrate this transition via large-scale numerical simulations. When microscopic non-reciprocal forces found in more common models of flocking are present, we show that they coarse-grain into additional hydrodynamic terms which non-reciprocally couple the density and momentum fields. This leads to a highly ordered clustered phase in metric models and restore the homogeneous flocking phase in topological models. |
Monday, March 6, 2023 10:36AM - 10:48AM Author not Attending |
A07.00012: Asymmetric Transport in Nonlinear Wave Chaos Chengzhen Wang, Rodion Kononchuk, Ulrich Kuhl, Tsampikos Kottos The intrinsic dynamical complexity of classically chaotic systems enforces a universal statistical description of the transport properties of their wave-mechanical analogues. These universal rules have been established within the framework of linear wave transport, where non-linear interactions are omitted, and the superposition principle holds. Many of these laws are described using phenomenological theories, like Random Matrix Theory (RMT), and have been established using toy models, that maintain the generic features of wave-chaos. Here, using a nonlinear complex graph, we exploit both experimentally and theoretically the interplay of nonlinear interactions and wave chaos. Our focus is on asymmetric transport (AT), its universal bounds, and its statistical description via RMT which are controlled by the structural asymmetry factor (SAF) characterizing the structure of the graph. The latter dictates the asymmetric intensity range (AIR) within which an incident wave demonstrates AT when injected from different ports. The AIR increases, without necessarily deteriorating the AT when losses are introduced. Our research initiates the quest for universalities and their violations in wave transport of nonlinear chaotic systems and has potential applications for the design of magnetic-free isolators. |
Monday, March 6, 2023 10:48AM - 11:00AM |
A07.00013: Abstract Withdrawn |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700