Thu. March 7, 10:24 a.m. – 10:36 a.m. CST
200IJ
Quantum computing is progressing towards industrial application, with estimation of molecular ground state energies as a likely early application. However, physical qubits and operations lack the necessary fidelity in order to approach chemical accuracy, even for small molecules. In order to assess the current state of the art, Quantinuum is carrying out case studies in fault-tolerant quantum chemistry.
Recently, Yamamoto et al. have used Bayesian phase estimation with an error-detecting code to estimate the ground state energy of Hydrogen using the Quantinuum H2 processor. In order to eliminate the overhead from logical gate synthesis, Yamamoto et al. opted to perform non-Clifford gates non-fault-tolerantly, limiting the scalability of their approach.
In the current work, we increase the code distance to three using the Steane code, and use gate teleportation to execute T gates, using magic states prepared fault-tolerantly. In order to minimize the resulting gate synthesis overhead (and therefore logical error rate), we use probabilistic angle interpolation, recently developed by Koczor et al., to replace precise Z-axis rotations with samples from an ensemble containing at most one T gate per rotation. This reduces the T-count of the circuits used by approximately an order of magnitude. We also explore post-selection on correctable errors as an avenue to reduce conditional logical error rates, and approach chemical accuracy.
Presented By
- Ben Criger (Quantinuum Ltd.)
Estimating the Ground State Energy of Hydrogen at Distance 3
Thu. March 7, 10:24 a.m. – 10:36 a.m. CST
200IJ
Recently, Yamamoto et al. have used Bayesian phase estimation with an error-detecting code to estimate the ground state energy of Hydrogen using the Quantinuum H2 processor. In order to eliminate the overhead from logical gate synthesis, Yamamoto et al. opted to perform non-Clifford gates non-fault-tolerantly, limiting the scalability of their approach.
In the current work, we increase the code distance to three using the Steane code, and use gate teleportation to execute T gates, using magic states prepared fault-tolerantly. In order to minimize the resulting gate synthesis overhead (and therefore logical error rate), we use probabilistic angle interpolation, recently developed by Koczor et al., to replace precise Z-axis rotations with samples from an ensemble containing at most one T gate per rotation. This reduces the T-count of the circuits used by approximately an order of magnitude. We also explore post-selection on correctable errors as an avenue to reduce conditional logical error rates, and approach chemical accuracy.
Presented By
- Ben Criger (Quantinuum Ltd.)