FTQC Emulator
The Fault-Tolerant Quantum Computing (FTQC) Emulator
The emulator is a link between the physical device and the rest of TopQAD. An emulation submodule takes in the physical characteristics of the device and outputs the logical performance of a fault-tolerant protocol. An extrapolator submodule builds on top of the logical statistics collected by the emulation submodule to derive the logical performance for code distances and topologies beyond the ones computationally accessible in simulation.
Theory
The noise characteristics of the device are used to construct an appropriate computational noise model, expressed as a set of Pauli channels, that is then applied to the protocol's circuit. The emulation module then leverages a Clifford circuit simulator and an appropriate decoder to model the execution of the protocol on the device. The logical error probability is accessed through Monte Carlo simulations required to sample the action of the noise channels. The extrapolator submodule leverages the emulation submodule to collect data that is required to predict the protocol performance for large distances.
Parameters
The input parameters are
| Parameter | Description |
|---|---|
| number_of_cores (optional) | Number of cores for the Monte Carlo sampling. Default is 8. |
| code | Default is [rotated_surface_code] |
| protocol | Default is [memory_z] |
| decoder | Default is [MWPM] |
| qubit_technology | Physical qubit technology. Default is [transmon] |
| noise_model | Default is [circuit_noise_with_idling] |
The output parameters are
| Parameter | Description |
|---|---|
| logical error probability | Default is for the memory-Z experiment |
Relevant Papers
[1] C. Gidney, Stim: A Fast Stabilizer Circuit Simulator, Quantum 5, 497 (2021), https://doi.org/10.22331/q-2021-07-06-497
[2] O. Higgott and C. Gidney, Sparse Blossom: correcting a million errors per core second with minimum-weight matching (2023), https://arxiv.org/abs/2303.15933.
[3] S. Aaronson and D. Gottesman, Improved simulation of stabilizer circuits, Phys. Rev. A 70, 052328 (2004),https://doi.org/10.1103/PhysRevA.70.052328