Quantum Algorithm for the Direct Calculations of Vertical Ionization Energies.

Area of Science:

• Quantum computing
• Computational chemistry
• Quantum algorithms

Background:

• Accurate calculation of electronic state energy gaps is crucial in chemistry.
• Existing quantum methods like Quantum Phase Estimation (QPE) are computationally expensive.
• Direct calculation of energy gaps without individual state energies offers potential efficiency gains.

Purpose of the Study:

• To propose a modified quantum circuit for direct spin state energy gap calculation.
• To extend this algorithm for calculating vertical ionization energies.
• To reduce qubit and gate requirements for quantum computations.

Main Methods:

• Development of a modified quantum circuit based on a recently proposed quantum algorithm.
• Implementation of numerical simulations for quantum circuits.
• Application to the ionization of various light atoms and small molecules.

Main Results:

• The modified quantum algorithm successfully calculates vertical ionization energies.
• Simulations achieved precision within 0.1 eV for tested atoms and molecules.
• The approach demonstrates reduced qubit and gate complexity.

Conclusions:

• The proposed quantum algorithm provides an efficient and precise method for determining vertical ionization energies.
• This advancement offers a more resource-efficient quantum computational approach for chemical applications.
• The algorithm's applicability to diverse chemical systems is validated through simulations.