Toward Quantum-Centric Simulations of Extended Molecules: Sample-Based Quantum Diagonalization Enhanced with Density...

Area of Science:

• Quantum computing
• Computational chemistry
• Electronic structure theory

Background:

• Computing molecular ground-state properties is crucial for chemistry and materials science.
• Quantum embedding methods offer a hybrid approach, combining quantum and classical computing for efficient calculations.
• Density Matrix Embedding Theory (DMET) is a powerful quantum embedding method.

Purpose of the Study:

• To present the first Density Matrix Embedding Theory (DMET) simulations combined with Sample-based Quantum Diagonalization (SQD).
• To compute ground-state properties of molecular systems using the novel DMET-SQD formalism.
• To demonstrate the potential of quantum-centric simulations for accurate electronic structure calculations.

Main Methods:

• Implementation of the DMET-SQD formalism for quantum embedding.
• Application to compute the ground-state energy of an 18-hydrogen atom ring.
• Calculation of relative energies for cyclohexane conformers using active-region simulations on quantum hardware (ibm_cleveland).

Main Results:

• Successful computation of ground-state energy for a ring of 18 hydrogen atoms.
• Accurate determination of relative energies for cyclohexane conformers.
• Validation of DMET-SQD results against established classical methods.
• Demonstration of decomposing large quantum simulations into smaller, manageable active-region simulations (27- and 32-qubit).

Conclusions:

• DMET-SQD represents significant progress in tackling larger active regions on near-term quantum computers.
• This work showcases the potential of quantum-centric simulations for accurate electronic structure calculations of large molecules.
• The ultimate goal is to apply these methods to complex systems like peptides and proteins.