Qubit Condensation for Assessing Efficacy of Molecular Simulation on Quantum Computers

Area of Science:

• Quantum Computing
• Computational Chemistry
• Quantum Mechanics

Background:

• Quantum computers leverage entanglement for potential advantages over classical devices.
• Preparing complex entangled states on current quantum hardware is challenging due to noise and errors.
• Existing metrics like gate errors do not directly assess entanglement quality for simulations.

Purpose of the Study:

• To introduce a novel metric, qubit condensation, for evaluating quantum device performance in simulating many-electron systems.
• To measure a quantum computer's capacity to generate highly entangled states with nonclassical long-range order.
• To validate the qubit condensation metric against established quantum computing benchmarks and simulation outcomes.

Main Methods:

• Developing a metric based on the "condensation of qubits" into a correlated particle-hole state.
• Preparing qubit condensations on diverse quantum computing platforms.
• Utilizing post-measurement analysis to quantify the realization of qubit condensation.
• Comparing the metric's device ranking with molecular simulation errors for H2.

Main Results:

• The qubit condensation metric effectively assesses the ability of quantum devices to prepare entangled states.
• The metric measures the generation of nonclassical long-range order across qubits.
• The ranking of quantum devices based on qubit condensation correlates with simulation errors from a contracted quantum eigensolver for H2.

Conclusions:

• Qubit condensation offers a direct measure of entanglement crucial for quantum simulations.
• This metric provides a more targeted evaluation of quantum hardware for simulating complex quantum systems.
• The findings suggest qubit condensation is a promising benchmark for advancing quantum computing capabilities in chemistry.