Experimental error mitigation via symmetry verification in a variational quantum eigensolver
| Autor: | Thomas E. O'Brien, V. P. Ostroukh, Leonardo DiCarlo, M. N. Singh, C.H. Price, Marc Beekman, Nadia Haider, Rol, Alessandro Bruno, X. Fu, C. C. Bultink, Nandini Muthusubramanian, R. Sagastizabal, Xavier Bonet-Monroig |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Density matrix
Hydrogen molecule Errors Ground state Experimental estimations Topology Residual Verification techniques 01 natural sciences 010305 fluids & plasmas symbols.namesake Ground-state energies 0103 physical sciences 010306 general physics Quantum Variational techniques Ansatz Physics Excited states Convex optimization Full density matrix Experimental errors Single excitation Quantum theory Qubit symbols Hamiltonian (quantum mechanics) Qubits State estimation Error mitigation |
| Zdroj: | Physical Review A: covering atomic, molecular, and optical physics and quantum information, 100(1) Physical Review A, 100(1), 010302. AMER PHYSICAL SOC Physical Review A, 1, 100 |
| ISSN: | 2469-9926 |
| Popis: | Variational quantum eigensolvers offer a small-scale testbed to demonstrate the performance of error mitigation techniques with low experimental overhead. We present successful error mitigation by applying the recently proposed symmetry verification technique to the experimental estimation of the ground-state energy and ground state of the hydrogen molecule. A finely adjustable exchange interaction between two qubits in a circuit QED processor efficiently prepares variational ansatz states in the single-excitation subspace respecting the parity symmetry of the qubit-mapped Hamiltonian. Symmetry verification improves the energy and state estimates by mitigating the effects of qubit relaxation and residual qubit excitation, which violate the symmetry. A full-density-matrix simulation matching the experiment dissects the contribution of these mechanisms from other calibrated error sources. Enforcing positivity of the measured density matrix via scalable convex optimization correlates the energy and state estimate improvements when using symmetry verification, with interesting implications for determining system properties beyond the ground-state energy. |
| Databáze: | OpenAIRE |
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