Quantum Information Driven Ansatz (QIDA): Shallow-Depth Empirical Quantum Circuits from Quantum Chemistry.

Area of Science:

• Quantum Computing
• Computational Chemistry
• Quantum Information Science

Background:

• Hardware-efficient empirical variational ansätze for Variational Quantum Eigensolver (VQE) simulations in quantum chemistry often lack direct links to classical methods.
• Developing compact and effective variational quantum circuits is crucial for accurate molecular simulations.

Purpose of the Study:

• To bridge the gap between classical quantum chemistry and quantum computing by proposing a novel method for constructing variational quantum circuits.
• To leverage quantum mutual information from classical states to design heuristic ansätze that reflect molecular correlations.

Main Methods:

• Utilized classical quantum chemistry calculations, such as MP2 perturbation theory, to obtain approximate Natural Orbitals.
• Evaluated the quantum mutual information matrix to identify key correlations between qubits.
• Designed entangling blocks for the quantum circuit based on mutual information, creating a topology reflecting molecular correlations.

Main Results:

• The proposed method generated effective ansätze for VQE simulations, outperforming the standard ladder-entangler ansatz.
• Simulations on molecular systems (H2, LiH, H2O, NH3) demonstrated the high performance of the developed ansätze.
• The approach yielded short-depth variational ground states of electronic Hamiltonians.

Conclusions:

• The novel methodology provides an effective route for state preparation in quantum computing.
• This approach offers a promising strategy for designing efficient variational quantum circuits for simulating large molecular systems.
• Integrating classical chemistry insights into quantum circuit design enhances VQE performance.