Doppelganger defects

Understand

We study k-defects - topological defects in theories with more than two derivatives and second-order equations of motion - and describe some striking ways in which these defects both resemble and differ from their analogues in canonical scalar field theories.

• We show that, for some models, the homotopy structure of the vacuum manifold is insufficient to establish the existence of k-defects, in contrast to the canonical case.
• These results also constrain certain families of DBI instanton solutions in the 4-dimensional effective theory.
• We then describe a class of k-defect solutions, which we dub doppelgangers, that precisely match the field profile and energy density of their canonical scalar field theory counterparts.