Cat-like quantum states confirmed in a three-photon chip

Researchers have, for the first time, confirmed the existence of three-component cat-like quantum states within a three-photon chip, moving beyond the standard two-component configuration. The work demonstrates quantum coherence through observed three-photon Rabi oscillations and direct Wigner function measurements, revealing a dynamic in phase space arising from macroscopic temporal interference. This oscillation frequency directly measures the energy gap separating the qutrit from the excited states, establishing a new time-domain method for verifying qutrit protection. However, the team identified a parasitic higher-order pump term as the primary limitation on achievable photon numbers, indicating a clear path for future development. The chip’s three-component cat-like states, distinguished by photon and Fock number modulo 3, establish a new approach to encoding quantum information beyond the standard two-component states. These states, designated |0C⟩, |1C⟩ and |2C⟩, form the qutrit manifold…