Quantum-interference-induced pairing in bosonic doped antiferromagnets

The pairing mechanism in doped antiferromagnets is essential for understanding high-temperature superconductivity. Here, we investigate the pairing mechanism in bosonic doped antiferromagnets via large-scale density matrix renormalization group calculations. In contrast to the competing orders in the fermionic case, we discover a robust pair density wave (PDW) coexists with the antiferromagnetic (AFM) order forming a "supersolid" at small doping in a bosonic t-J model. The pairing order collapses at larger doping to a single-boson condensate with a ferromagnetic (FM) order. The pairing phase will disappear once a hidden many-body Berry phase is switched off. Such a Berry phase introduces the sole "sign problem" in this bosonic model and imposes quantum phase frustration to the interference pattern between spin and charge degrees of freedom. Only via tightly pairing of doped holes, can such frustration be most effectively erased in an AFM background. By contrast, the pairing vanishes as the Berry phase is trivialized in an FM background or switched off into the Bose-Hubbard model at large U. The present pairing mechanism—distinct from the conventional mechanisms based on Fermi surface instabilities—may provide a different perspective and new insights for understanding the complex nature of doped Mott insulators, and is promising to be probed on qudit-based quantum simulators such as ultracold Rydberg atom arrays.