Supersolitons in a 2D anisotropic semimetal

We study the effects of strong correlations on far- from-equilibrium quantum transport. We consider a
2D anisotropic semimetal model that can arise in several material systems, from strained graphene to
black phosphorous, and that has been realized in ultracold fermion atoms via optical lattices.
An interesting feature of this model is that it can be smoothly deformed between two limits. The model
has linear dispersion in one direction and n-fold dispersion in the other. For n = 2 (appropriate to
the strained honeycomb lattice), the model is fully two-dimensional, while the limit n →
∞ corresponds to uncoupled 1D wires. Short-range interactions induce Luttinger liquid (LL) physics
within the wires.
Here we consider a quantum quench between these two limits. We quench from an initial condition
consisting of uncoupled LLs to the 2D noninteracting semimetal (where interactions are irrelevant in
equilibrium). We find that the quench induces a non-equilibrium density profile that contains
``supersolitons,’’ collective density waves whose spatial profile is determined by the degree of
fractionalization in the initial strongly correlated state.×