Fig. 4: Quasiparticle band spectra from multiple excited-state calculation.
From: Solving quasiparticle band spectra of real solids using neural-network quantum states
a Schematic diagram of the trans-polyacetylene (C2H2)n. The cyan and gray spheres indicate the carbon and hydrogen atoms, respectively. b Three quasiparticle bands below and above the Fermi energy. Here, the yellow lines and black dashed lines indicate results obtained from the equation-of-motion coupled-cluster (EOM-CC) formalism; CCSD and CCSD(T) stand for the unperturbed EOM-CCSD and the perturbed EOM-CCSD(T)(a)*methods, respectively. The blue dotted lines denote the restricted Hartree–Fock (RHF) method. c A zoom-in of the first conduction band, which is computed from the electron attatchment (EA) energy. It is clearly shown, from the energy differences against the EA-EOM-CCSD(T)(a)* method, that the results by the RBM (green triangle) are comparable or better than the unperturbed EA-EOM-CCSD method. In all calculations, a single k-point is taken under the minimal basis set (STO-3G) and hence 24 spin orbitals are taken into account. The size of the unit cell is taken as 2.451 Å.
