Direct verification of vortex–antivortex dipole annihilation at shear-band onset

Establish, through direct high–strain-resolution measurement or proof, whether a vortex–antivortex dipole annihilates immediately prior to the onset of shear-band flow in two-dimensional glasses subjected to athermal quasistatic shear, and quantify the timing and energetics of this event.

Background

The authors consistently observe that a large, distant vortex–antivortex dipole disappears as the shear band begins to flow, and argue it is very likely that an annihilation event occurs at the onset. They suggest this could release energy that is funneled into a solitonic rarefaction pulse, drawing an analogy to superfluid systems where vortex–antivortex annihilation emits such pulses.

However, due to limited strain resolution, they cannot directly prove the annihilation and provide only a reductio ad absurdum argument. A direct verification would pin down the causal dynamics linking defect annihilation to the initiation of shear-band flow and test the proposed rarefaction-pulse mechanism.