Shengjie Jin, Wenjun Zhang, Xinxin Guo, Xuzong Chen, Xiaoji Zhou, and Xiaopeng Li. "Evidence of potts-nematic superfluidity in a hexagonal sp2 optical lattice."

Abstract: As in between liquid and crystal phases lies a nematic liquid crystal, which breaks rotation with preservation of translation symmetry, there is a nematic superfluid phase bridging a superfluid and a supersolid. The nematic order also emerges in interacting electrons and has been found to largely intertwine with multiorbital correlation in high-temperature superconductivity, where Ising nematicity arises from a four-fold rotation symmetry C4 broken down to C2. Here, we report an observation of a three-state (Z3) quantum nematic order, dubbed “Potts-nematicity”, in a system of cold atoms loaded in an excited band of a hexagonal optical lattice described by an -orbital hybridized model. This Potts-nematic quantum state spontaneously breaks a three-fold rotation symmetry of the lattice, qualitatively distinct from the Ising nematicity. Our field theory analysis shows that the Potts-nematic order is stabilized by intricate renormalization effects enabled by strong interorbital mixing present in the hexagonal lattice. This discovery paves a way to investigate quantum vestigial orders in multiorbital atomic superfluids.