Pseudo-Hydrodynamic Flow of Quasiparticles in Semimetal WTe at Room Temperature.

Recently, much interest has emerged in fluid-like electric charge transport in various solid-state systems. The hydrodynamic behavior of the electronic fluid reveals itself as a decrease of the electrical resistance with increasing temperature (the Gurzhi effect) in narrow channels, polynomial scaling of the resistance as a function of the channel width, violation of the Wiedemann-Franz law supported by the emergence of the Poiseuille flow. Similar to whirlpools in flowing water, the viscous electronic flow generates vortices, resulting in abnormal sign-changing electrical response driven by backflow.

Fractal energy carpets in non-Hermitian Hofstadter quantum mechanics.

We study the non-Hermitian Hofstadter dynamics of a quantum particle with biased motion on a square lattice in the background of a magnetic field. We show that in quasimomentum space, the energy spectrum is an overlap of infinitely many inequivalent fractals. The energy levels in each fractal are space-filling curves with Hausdorff dimension 2.

Topological solitons and folded proteins.

We argue that protein loops can be described by topological domain-wall solitons that interpolate between ground states which are the α helices and β strands. We present an energy function that realizes loops as soliton solutions to its equation of motion, and apply these solitons to model a number of biologically active proteins including 1VII, 2RB8, and 3EBX (Protein Data Bank codes). In all the examples that we have considered we are able to numerically construct soliton solutions that reproduce secondary structural motifs such as α-helix-loop-α-helix and β-sheet-loop-β-sheet with an overall root-mean-square-distance accuracy of around 1.