Performance Validation¶
This document contains specification and explanation of the hardware error definitions and benchmarks as reported in the Product Data Sheets. The code to perform analysis for the hardware specification data in the Product Data Sheets can be found in the specified GitHub repository.
Component Benchmarks¶
Component-level benchmarks capture the failure rate of specific quantum operations. These type of benchmarks are easier to interpret. Component validation is used in system-level models to better understand complete error budget.
1-qubit gate fidelity¶
The 1-qubit gate fidelity is measured using 1-qubit randomized benchmarking (RB) with random 1-qubit Clifford gates[1]. 1-qubit RB also uses final gate randomization to fix the asymptote of the RB decay curve, in order to reduce the number of fit parameters and allow fitting of shorter sequences [2]. We run 1-qubit RB with two qubits per active gate zone in parallel. The error rate is calculated by translating the RB decay curve to a per-Clifford average infidelity under the standard RB assumptions. Uncertainty is calculated from a semi-parametric bootstrap resampling of the collected data.
The spontaneous emission rate is also measured from 1-qubit RB experiments by applying a “leakage gadget” to the end of each circuit, which detects if a qubit leaks out of the computational subspace[3]. The number of leakage events depends on the number of gates applied and the spontaneous emission rate. By fitting the number of detected leakage events as a function of number of gates, we can extract an estimate of the spontaneous emission rate.
2-qubit gate fidelity¶
The 2-qubit gate fidelity is measured with 2-qubit RB using similar methods outlined above on 1-qubit RB. 2-qubit RB is run with 2-qubit random Clifford gates on pairs of qubits in each active gate zone in parallel. The infidelity of our native entangling gate is estimated by scaling per-Clifford infidelity by the average number of entangling gates per Clifford (= 1.5). Datasets are also used to estimate the spontaneous emission rate using the leakage gadget described above, but with a scaling for the number of 2-qubit gates per Clifford.
Memory error per qubit at depth-1 circuit time¶
To characterize memory error in depth-1 circuit time, we perform 1-qubit RB as described above, while interleaving specialized qasm commands that force transport to create random 2-qubit pairings and run the preset cooling. The net RB error measured is the 1-qubit and memory error, averaged across all qubits, due to depth-1 circuits. We perform this test for all available qubits in the system. The figures below average across the survival rate across all qubits on the system.
State preparation and measurement (SPAM) error¶
The SPAM error is measured by preparing the qubits in the \(|0\rangle\) (or \(|1\rangle\) state) and measuring to determine the fraction of time the incorrect \(|1\rangle\) (or \(|0\rangle\)) state is returned. The reported SPAM error is the average between the \(|0\rangle\) and \(|1\rangle\) state-preparation experiments. All gate zones are measured in parallel, and the experiment is performed on both of the qubits (left and right in below data) in each active gate zone.
Avg. SPAM error |
Avg. SPAM error uncertainty |
0 SPAM error |
1 SPAM error |
|
G1-left |
2.35e-03 |
3.42e-04 |
7.00e-04 |
4.00e-03 |
G1-right |
2.25e-03 |
3.35e-04 |
7.00e-04 |
3.80e-03 |
G2-left |
2.45e-03 |
3.49e-04 |
1.00e-03 |
3.90e-03 |
G2-right |
3.05e-03 |
3.90e-04 |
1.10e-03 |
5.00e-03 |
G3-left |
2.60e-03 |
3.60e-04 |
5.00e-04 |
4.70e-03 |
G3-right |
2.15e-03 |
3.27e-04 |
3.00e-04 |
4.00e-03 |
G4-left |
2.55e-03 |
3.57e-04 |
1.80e-03 |
3.30e-03 |
G4-right |
2.25e-03 |
3.35e-04 |
1.30e-03 |
3.20e-03 |
G5-left |
2.65e-03 |
3.63e-04 |
1.00e-03 |
4.30e-03 |
G5-right |
2.30e-03 |
3.39e-04 |
1.10e-03 |
3.50e-03 |
Mean |
2.46e-03 |
1.11e-04 |
9.50e-04 |
3.97e-03 |
Avg. SPAM error |
Avg. SPAM error uncertainty |
0 SPAM error |
1 SPAM error |
|
G1-left |
1.50e-03 |
2.74e-04 |
8.00e-04 |
2.20e-03 |
G1-right |
1.80e-03 |
3.00e-04 |
8.00e-04 |
2.80e-03 |
G2-left |
1.30e-03 |
2.55e-04 |
3.00e-04 |
2.30e-03 |
G2-right |
1.50e-03 |
2.74e-04 |
4.00e-04 |
2.60e-03 |
G3-left |
1.25e-03 |
2.50e-04 |
1.00e-03 |
1.50e-03 |
G3-right |
1.80e-03 |
2.99e-04 |
1.00e-04 |
3.50e-03 |
G4-left |
1.40e-03 |
2.64e-04 |
3.00e-04 |
2.50e-03 |
G4-right |
1.40e-03 |
2.64e-04 |
3.00e-04 |
2.50e-03 |
Mean |
1.49e-03 |
9.65e-05 |
5.00e-04 |
2.49e-03 |
Mid-circuit measurement cross-talk error¶
Although qubits are physically separated during measurement and reset, there is a small chance that an unmeasured qubit in the \(|1\rangle\) state will absorb the detection light, destroying its quantum state, and potentially scattering to the non-computational states used for state detection. This is not an issue with measurement at the end of a circuit when all qubits are measured but can impact circuits with mid-circuit measurement and reset. The mid-circuit measurement and reset cross-talk errors are quantified by the population decay of an unmeasured qubit while applying many measurement or reset pulses to a neighboring qubit [4].
