Projective quantum eigensolver via adiabatically decoupled subsystem evolution: A resource efficient approach to...

Area of Science:

• Quantum Computing
• Computational Chemistry
• Quantum Information Science

Background:

• Current quantum hardware noise limits applications in computational chemistry.
• Solving complex many-body problems in chemistry requires advanced computational methods.
• Noisy Intermediate-Scale Quantum (NISQ) devices present challenges for accurate chemical simulations.

Purpose of the Study:

• Develop a projective formalism for accurate ground-state energy calculations of molecular systems.
• Enable efficient use of NISQ hardware for chemical problems.
• Create a resource-efficient quantum algorithm for chemistry.

Main Methods:

• Formulation of a bipartitely decoupled parameterized ansatz.
• Utilizing the disentangled unitary coupled cluster framework.
• Incorporating principles of nonlinear dynamics and synergetics for parameter optimization.
• Non-iterative energy correction exploiting synergistic parameter relationships.

Main Results:

• Achieved a compact, fixed-depth ansatz with shallower circuits.
• Reduced the number of required expectation value evaluations.
• Demonstrated superior performance under noise compared to existing methods.
• Ensured requisite accuracy for future fault-tolerant quantum systems.

Conclusions:

• The developed projective formalism accurately computes molecular ground-state energies on noisy quantum hardware.
• The method is resource-efficient, enabling rapid exploration of chemical spaces.
• This approach enhances the utility of NISQ devices for computational chemistry.
• The formalism provides a pathway for accurate quantum simulations in both NISQ and fault-tolerant regimes.