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Now showing items 141-150 of 278
Helical propulsion in shear-thinning fluids
(Cambridge University PressJournal of Fluid Mechanics, 2017-02-01)
Swimming micro-organisms often have to propel themselves in complex non-Newtonian fluids. We carry out experiments with self-propelling helical swimmers driven by an externally rotating magnetic field in shear-thinning ...
Isoscalar ππ Scattering and the σ Meson Resonance from QCD
(American Physical SocietyPhysical Review Letters, 2017-01-13)
We present for the first time a determination of the energy dependence of the isoscalar ππ elastic scattering phase shift within a first-principles numerical lattice approach to QCD. Hadronic correlation functions are ...
Microscale flow dynamics of ribbons and sheets
(Royal Society of ChemistrySoft Matter, 2017-01-18)
Numerical study of the hydrodynamics of thin sheets and ribbons presents difficulties associated with resolving multiple length scales. To circumvent these difficulties, asymptotic methods have been developed to describe ...
Coherent structures in interacting vortex rings
(American Physical SocietyPhysical Review Fluids, 2017-02-21)
We investigate experimentally the nonlinear structures that develop from interacting vortex rings induced by a sinusoidally oscillating ellipsoidal disk in fluid at rest. We vary the scaled amplitude or Keulegan-Carpenter ...
Autophoretic flow on a torus
(American Physical SocietyPhysical Review Fluids, 2017-03-02)
Phoretic swimmers provide new avenues to study nonequilibrium statistical physics and are also hailed as a promising technology for bioengineering at the cellular scale. Exact solutions for the locomotion of such swimmers ...
Dynamical α-cluster model of $^{16}$O
(American Physical SocietyPhysical Review C, 2017-03-09)
We calculate the low-lying spectrum of the $^{16}$O nucleus using an α-cluster model which includes the important tetrahedral and square configurations. Our approach is motivated by the dynamics of α-particle scattering ...
MRI turbulence and thermal instability in accretion discs
(Oxford University PressMonthly Notices of the Royal Astronomical Society, 2017-06)
A long-standing puzzle in the study of black hole accretion concerns the presence or not of thermal instability. Classical theory predicts that the encircling accretion disc is unstable, as do some self-consistent ...
Active matter logic for autonomous microfluidics
(Nature Publishing GroupNature Communications, 2017-04-25)
Chemically or optically powered active matter plays an increasingly important role in materials design, but its computational potential has yet to be explored systematically. The competition between energy consumption and ...
Anti-de Sitter Particles and Manifest (Super)Isometries.
(American Physical SocietyPhysical Review Letters, 2017-04-07)
Starting from the classical action for a spin-zero particle in a D-dimensional anti-de Sitter (AdS) spacetime, we recover the Breitenlohner-Freedman bound by quantization. For D=4, 5, 7 and using an Sl(2;K) spinor notation ...
Maximum magnetic moment to angular momentum conjecture
(American Physical SocietyPhysical Review D, 2017-03-24)
Conjectures play a central role in theoretical physics, especially those that assert an upper bound to some dimensionless ratio of physical quantities. In this paper we introduce a new such conjecture bounding the ratio ...