Topological Phases Driven by Anisotropic Four‐Spin Interactions in 1D Spin‐1/2 XX Chains

ABSTRACT In this study, we investigate the emergence of non‐trivial topological phases in a 1D spin‐1/2 XX model induced by anisotropic four‐spin interactions. By employing the fermionization technique, we precisely diagonalize the system's Hamiltonian and analytically identify three critical lines. Subsequently, we calculate the energy gap, fidelity susceptibility, cluster local order parameters, winding number, and entanglement spectrum. Our findings identify three crucial boundaries that divide five gapped phases, each characterized by the coexistence of symmetry‐protected topological order and spontaneous symmetry breaking. Analyzing the winding number as a topological invariant allows us to distinguish these gapped phases as distinct non‐trivial topological phases, characterized by integer values of . Moreover, we observe topological phase transitions at quantum critical points, where the winding number changes are associated with the closing and reopening of the energy gap. Furthermore, we demonstrate that for a given winding number , the degeneracy of the lowest eigenvalue in the entanglement spectrum is generally . This work provides novel insights into the role of anisotropic four‐spin interactions in driving topological phenomena in low‐dimensional quantum systems, offering a deeper understanding of the interplay between topology and quantum fluctuations.