posted on 2024-01-03, 15:05authored byJiace Sun, Lixue Cheng, Weitang Li
Achieving chemical accuracy with shallow quantum circuits
is a
significant challenge in quantum computational chemistry, particularly
for near-term quantum devices. In this work, we present a Clifford-based
Hamiltonian engineering algorithm, namely CHEM, that
addresses the trade-off between circuit depth and accuracy. Based
on a variational quantum eigensolver and hardware-efficient ansatz,
our method designs the Clifford-based Hamiltonian transformation that
(1) ensures a set of initial circuit parameters corresponding to the
Hartree–Fock energy can be generated, (2) effectively maximizes
the initial energy gradient with respect to circuit parameters, (3)
imposes negligible overhead for classical processing and does not
require additional quantum resources, and (4) is compatible with any
circuit topology. We demonstrate the efficacy of our approach using
a quantum hardware emulator, achieving chemical accuracy for systems
as large as 12 qubits with fewer than 30 two-qubit gates. Our Clifford-based
Hamiltonian engineering approach offers a promising avenue for practical
quantum computational chemistry on near-term quantum devices.