New

• In classical systems, the width of a chaotic region can be estimated from the integral of a perturbation along the separatrix orbit. We derive an analogous relation for a discrete quantum system by taking the average of the perturbation in the interaction picture and using an eigenstate state with energy near that of the separatrix. Quantum chaos on the separatrix of the periodically perturbed Harper model (on arxiv)

Classical orbits on the left. Husimi functions showing phase space of Floquet states of the associated quantum system on the right.
• Ejecta from oblique impacts is remarkably lopsided. Most of the mass goes in the downrange direction. Sometimes low-tech experiments are surprisingly interesting! (Sean's experiments!) The azimuthal distribution of ejecta mass from oblique impacts into sand (on arxiv)
• Arrokoth's smooth undulating terrain suggests that it was sandblasted by the snowstorm in which it coalesced. Wind erosion and transport on planetesimals (on arxiv) or ADS/Icarus
• Bridging between quantum and classical phenomena on a quantum computer Generating quantum channels from functions on discrete sets (on arxiv) , in Quantum Information processing
• On oblique impacts (led by Bingcheng). Subsurface pulses are strongly (x5) asymmetric even when the resulting crater is round. Subsurface pulse, crater and ejecta asymmetry from oblique impacts into granular media (on arxiv) , ADS/Icarus
• On directional phase oscillator models for metachronal wave formation Robust formation of metachronal waves in directional chains of phase oscillators (on arxiv), Phys Rev E
• We measure circulation in a drop that is caused by vinegar eels that are collectively organized in a metachronal wave, Fluid circulation driven by collectively organized metachronal waves in swimming T. aceiti nematodes (on arxiv) , in Phys Rev E
• Surface motions associated with a normal impact outside the crater and before the ejecta curtain lands are tracked using PIV and cross correlation in high speed videos. on arxiv , in Icarus
• Seismic pulse propagation in asteroids. We carry out experiments of impacts into granular media (a washtub of millet) using a 7 channel accelerometer array. Attenuation is rapid. We use a diffusive approximation to predict how the signal strength decays as a function of pulse propagation distance and we make some predictions for the DART mission. on arxiv , In Icarus
• We predict that the secondaries of binary asteroids are in complex rotation states.
  Non-principal axis rotation in binary asteroid systems and how it weakens the BYORP effect, arxiv , ADS/Icarus
• Collective phenomena in swimming nematodes:
  Metachronal waves in concentrations of swimming Turbatrix aceti nematodes and an oscillator chain model for their coordinated motions, (arxiv) , in Phys Rev E
  
  Above is an animation based on an oscillator chain model for the vinegar eels involved in the metachronal wave.
  Also see video of vinegar eels doing the wave