Sign structure of the $t$-$t^\prime$-$J$ model and its physical consequences

Understand

Understanding the doped Mott insulator is a central challenge in condensed matter physics.

• In this work, we first explicitly identify a new sign structure in the $t$-$t'$-$J$ model on the square lattice that replaces the conventional Fermi statistics for weakly interacting electrons.
• Then we show that the singular, i.e., the phase-string part of the sign structure in the partition function can be precisely turned off in a modified model.
• The density matrix renormalization group method is then employed to study these two models comparatively on finite-size systems, which is designed to unveil the consequences of the phase-string component.