Controlling noisy herds.

The wisdom of the crowd breaks down in small groups. While large flocks exhibit swarm intelligence to evade predators, small groups display erratic behavior, oscillating between unity and discord. We investigate these dynamics using small groups of sheep controlled by shepherd dogs in century-old sheepdog trials, proposing a two-parameter stochastic dynamic framework.

Ultrafast reversible self-assembly of living tangled matter.

Tangled active filaments are ubiquitous in nature, from chromosomal DNA and cilia carpets to root networks and worm collectives. How activity and elasticity facilitate collective topological transformations in living tangled matter is not well understood. We studied California blackworms (), which slowly form tangles in minutes but can untangle in milliseconds.

Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices.

Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a LaSrMnO/HfZrO capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction.

Null model exhibiting synchronized dynamics in uncoupled oscillators.

The phenomenon of phase synchronization of oscillatory systems, arising out of feedback coupling is ubiquitous across physics and biology. In noisy, complex systems, one generally observes transient epochs of synchronization followed by nonsynchronous dynamics. How does one guarantee that the observed transient epochs of synchronization are arising from an underlying feedback mechanism and not from some peculiar statistical properties of the system? This question is particularly important for complex biological systems, where the search for a nonexistent feedback mechanism may turn out to be an enormous waste of resources.