12 research outputs found
Cross-fertilization of Ferreira's Hopfions And Electromagnetic Knots
The interrelation between Ferreira's Hopf solitons of a conformal nonlinear
model and the electromagnetic knots found by Raada et
al. is investigated. It is shown that the electromagnetic knots yield exact
solutions of the conformal nonlinear model different from those
obtained by Ferreira. Conversely, It is discussed that Ferreira's solutions
realize magnetic knots. The energy associated with these two kinds of knots are
compared. The structure of the electric charge distribution and the electric
current density associated with the magnetic knots is investigated
Polychromatic photonic quasicrystal cavities
Quantum Matter and Optic
Diffraction-limited high-finesse optical cavities
Quantum Matter and Optic
Motile dislocations knead odd crystals into whorls
The competition between thermal fluctuations and potential forces governs the stability of matter in equilibrium, in particular the proliferation and annihilation of topological defects. However, driving matter out of equilibrium allows for a new class of forces that are neither attractive nor repulsive, but rather transverse. The possibility of activating transverse forces raises the question of how they affect basic principles of material self-organization and control. Here we show that transverse forces organize colloidal spinners into odd elastic crystals crisscrossed by motile dislocations. These motile topological defects organize into a polycrystal made of grains with tunable length scale and rotation rate. The self-kneading dynamics drive super-diffusive mass transport, which can be controlled over orders of magnitude by varying the spinning rate. Simulations of both a minimal model and fully resolved hydrodynamics establish the generic nature of this crystal whorl state. Using a continuum theory, we show that both odd and Hall stresses can destabilize odd elastic crystals, giving rise to a generic state of crystalline active matter. Adding rotations to a material’s constituents has far-reaching consequences for continuous control of structures and transport at all scales.The National Science Foundation (NSF) under award no. DMR-2011854.
NSF DMR-1905974, NSF EFRI NewLAW 1741685 and the Packard Foundation.
NSF grants DMR-1420073 (NYU-MRSEC) and DMR-2004469.
ARN grant WTF and IdexLyon Tore.
The National Science Foundation Graduate Research Fellowship under grant no. 1746045. D.B.
The Chicago-France FACCTS programme.
‘la Caixa’ Foundation (ID 100010434), fellowship LCF/BQ/PI20/11760014 and from the European Union’s Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement no. 847648.
NSF DMR-1828629 and US NSF grant no. DMR-201185
Strong coupling through optical positioning of a quantum dot in a photonic crystal cavity
Quantum Matter and Optic
High finesse opto-mechanical cavity with a movable thirty-micron-size mirror
Quantum Matter and Optic
The management of short term decision making in practice
SIGLEAvailable from British Library Document Supply Centre- DSC:DXN055201 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Lock and key colloids through polymerization-induced buckling of monodisperse silicon oil droplets
We have developed a new simple method to fabricate bulk amounts of colloidal spheres with well defined cavities from monodisperse emulsions. Herein, we describe the formation mechanism of ‘‘reactive’’ silicon oil droplets that deform to reproducible shapes via a polymerization-induced buckling instability. Owing to their unique shape, the resulting particles can be successfully used as colloidal building blocks in the assembly of composite clusters via ‘‘lock-andkey’’ interactions
Topological mechanics of gyroscopic metamaterials.
Theoretical Physic
Cubic crystals from cubic colloids
We have studied the crystallization behavior of colloidal cubes by means of tunable depletion interactions. The colloidal system consists of novel micron-sized cubic particles prepared by silica deposition on hematite templates and various non-adsorbing watersoluble polymers as depletion agents. We have found that under certain conditions the cubes self-organize into crystals with a simple cubic symmetry, which is set by the size of the depletant. The dynamic of crystal nucleation and growth is investigated, monitoring the samples in time by optical microscopy. Furthermore, by using temperature sensitive microgel particles as depletant it is possible to fine tune depletion interactions to induce crystal melting. Assisting crystallization with an alternating electric field improves the uniformity of the cubic pattern allowing the preparation of macroscopic (almost defect-free) crystals that show visible Bragg colors