Y. Lyu, Sinya Aoki, Takumi Doi, Tetsuo Hatsuda, Kotaro Murakami, Takuya Sugiura
A systematic way to constructing optimized interpolating operators for two-hadron systems is developed by incorporating interhadron spatial wave functions. The wave functions can be obtained from an iterative process with an appropriate initial guess. To implement these operators, a novel quark smearing technique utilizing Z 3 noise vectors is proposed, which allows for effectively incorporating interhadron spatial wave functions at the source without using all-to-all quark propagators. Proof-of-principle application to the Ω c c c Ω c c c system using physical-point lattice configurations with a large size L a ≃ 8.1 fm demonstrates that optimized operators outperform combinations of limited plane wave operators in the variational analysis, enabling clear identification of states around 2 m Ω c c c ≃ 9700 MeV with the energy gap as narrow as ∼ 5 MeV . A comparison on correlation functions, effective energies, and HAL QCD potentials between unoptimized operators and optimized operators is given, with a special emphasis on the effects from nearby elastic scattering states. Potential applicability of the optimized operator to various two-hadron systems and its relation to the variational method are also discussed.