Detecting fractionalization in quantum spin liquids using tensor networks

Quantum spin liquids (QSLs) are long-range entangled states of matter characterized by fractionalized degrees of freedom. The direct experimental detection of these fractionalized particles remains a substantial challenge. Based on the single-mode approximation iPEPS algorithm, we investigated the spin dynamics in the Kitaev honeycomb model under an out-of-plane magnetic field, a system exhibits a transition from a gapped chiral spin liquid (CSL) phase to a debated intermediate gapless phase (IGP). We identified experimentally detectable signatures of fractionalized excitations in the chiral spin liquid phase, where the flux and Majorana fermion freedoms are separable. Our dynamical results confirm the IGP phase is indeed gapless and indicate the nature of the IGP may be a Majorana metal induced by strong flux fluctuations.