When soft crystals defy Newton's third law: Non-reciprocal mechanics and dislocation motility

TL;DR

This paper demonstrates that non-reciprocal interactions in driven soft crystals lead to novel non-reciprocal mechanics, causing dislocations to become motile and challenging traditional Newtonian physics in elastic materials.

Contribution

It introduces six classes of non-reciprocal elastic mechanics and shows how dislocations can spontaneously become motile due to these interactions.

Findings

Non-reciprocal interactions induce motile dislocations.

Six classes of non-reciprocal elastic mechanics identified.

Dislocations glide steadily in periodic lattices due to non-reciprocity.

Abstract

The effective interactions between the constituents of driven soft matter generically defy Newton's third law. Combining theory and numerical simulations, we establish that six classes of mechanics with no counterparts in equilibrium systems emerge in elastic crystals challenged by nonreciprocal interactions. Going beyond linear deformations, we reveal that interactions violating Newton's third law generically turn otherwise quiescent dislocations into motile singularities which steadily glide though periodic lattices.