Quantum density-assisted hopping sparks superconductivity in a key model

Researchers at the University of Bonn, ENSL, and the University of Salerno have demonstrated how density-assisted hopping can induce superconductivity in a system normally resistant to it. The work reveals that this hopping creates an attractive interaction within the lower energy band of dimerized lattices, overcoming onsite repulsion and potentially leading to superconductivity with a pairing structure beyond the common s-wave form. Characterizing a shift between repulsive and superconducting states, the team identified this transition as a Berezinskii-Kosterlitz-Thouless transition, mapping the phase diagram of a two-leg ladder system with both numerical and analytical methods. Parameters used in the modeling included a filling of n = 0.9375 and a ladder length of L = 80, demonstrating the conditions under which this transition occurs within the dimerized lattice geometry. This finding builds on work exploring the theoretical description of high critical temperature superconductivity, a central challenge in condensed matter physics, and utilizes the two-dimensional Hubbard model as…