Demonstration of Adiabatic Variational Quantum Computing with a Superconducting Quantum Coprocessor.

Area of Science:

• Quantum Computing
• Quantum Many-Body Physics
• Superconducting Circuits

Background:

• Adiabatic quantum computing (AQC) is a powerful method for preparing ground states but faces experimental challenges.
• Analog AQC requires complex Hamiltonian engineering, while digital AQC needs deep quantum gate circuits.

Purpose of the Study:

• To propose and experimentally demonstrate a new hybrid algorithm that overcomes AQC implementation challenges.
• To efficiently prepare many-body ground and excited eigenstates using a variational approach.

Main Methods:

• Developed an adiabatic variational hybrid algorithm utilizing short quantum circuits.
• Employed systematic quantum adiabatic optimization of circuit parameters.
• Experimentally demonstrated the algorithm on a multiqubit superconducting coprocessor.

Main Results:

• Achieved efficient preparation of many-body eigenstates.
• Demonstrated high-fidelity state preparation, reaching approximately 99% fidelity.
• Successfully tracked real-time evolution of ground and excited states of transverse-field Ising spins.

Conclusions:

• The adiabatic variational hybrid algorithm offers a practical solution for preparing complex quantum states.
• This method bypasses the limitations of traditional analog and digital adiabatic quantum computing.
• Experimental validation confirms the algorithm's potential for advancing quantum computation and simulation.