Quantum Monte Carlo simulation of superconducting state of strongly correlated systems

Kamlesh Kumari, Ishwar S Singh

C. Lavalle, Salvatore R. Manmana, Stefan Weßel +1 more

Stefan Weßel, A. Muramatsu

A. Muramatsu, G. Dopf, J. Wagner +2 more

I. Morgenstern, M. Frik, Wolfgang von der Linden

We present quantum simulation studies for a system of strongly correlated fermions coupled to local anharmonic phonons. The Monte Carlo calculations are based on a generalized version of the Projector Quantum Monte Carlo Method allowing a simultaneous treatment of fermions and dynamical phonons. The numerical simulations yield exact results in the electron-phonon parameter regime relevant for high-Tc superconductivity, which is not accessible by perturbative methods like Eliashberg-Theory. The class of electron-phonon-models covered in the simulations describes superconductivity exhibiting several features of the new high-Tc materials.

Sibo Guo, Wei-Xuan Chang, Yi-Zhuang You +1 more

Understanding unconventional superconductivity (SC) driven by strong electronic correlations is a central challenge in condensed matter physics. In this work, we employ sign-problem-free quantum Monte Carlo (QMC) simulations to systematically investigate a bilayer fermionic model featuring strong interlayer antiferromagnetic (AFM) exchange and on-site repulsive Hubbard interactions. This system serves as a prototypical model for realizing a symmetric mass generation (SMG) insulator. Our numerically exact results unambiguously demonstrate that robust superconducting pairing emerges upon doping the SMG phase. Remarkably, we find that the SC order is significantly enhanced by the repulsive Hubbard interaction. Given its potential relevance to the essential features of the high-$T_c$ superconductor $\mathrm{La}_{3}\mathrm{Ni}_{2}\mathrm{O}_{7}$ under pressure, our study establishes a new paradigm for superconductivity arising from a doped SMG parent state and provides key theoretical guidance for future experimental investigations.