10.26434/chemrxiv.9863810.v1
Yuji Mochizuki
Koji Okuwaki
Takumi Kato
Yuichiro Minato
Reduction of Orbital Space for Molecular Orbital Calculations with Quantum Computation Simulator for Educations
2019
ChemRxiv
molecular orbital
frozen core
pseudo natural orbital
quantum computation
teaching material
2019-09-24 16:33:24
article
https://chemrxiv.org/articles/Reduction_of_Orbital_Space_for_Molecular_Orbital_Calculations_with_Quantum_Computation_Simulator_for_Educations/9863810
Recently, the molecular orbital (MO) calculations with quantum computations (QCs) have attracted considerable interest. The cost of QCs highly depends on the number of qubits even on quantum simulators. The reduction of MO space can thus be a crucial issue for the practical applicability of MO-QC. Besides the frozen-core restriction for the occupied MO space, we have used the pseudo-natural orbital derived from the second-order M{\o}ller-Plesset perturbation (MP2) theory for the virtual MO space. A preliminary test on the LiH molecule (STO-3G basis) showed acceleration by a factor larger than 500 for MO-QC with the Blueqat simulator, where the required time was 72 s per solution. Simulations of MO-QC may be used as practical teaching materials in classes.