A Magic Trick for Simulating Quantum Computers
Running a large-scale fault-tolerant quantum computer will require efficient ways of preparing quantum states known as logical magic states. These are noise-protected resources that enable a quantum computer to carry out the operations that confer its prodigious computing power. Now Samyak Surti and his colleagues at the University of California, Davis, have demonstrated an optimized method for simulating, on a classical computer, the preparation of logical magic states [1]. Scientists will be able to use such simulations to test and refine preparation protocols before running them on quantum hardware.
The preparation of logical magic states is affected by noise-induced errors. In real devices, these can take many forms, but for the purposes of simulation, they are typically modeled as so-called Pauli errors that ordinarily must be tracked throughout the computation. The simulation method developed by Surti and his colleagues exploits the fact that, for many practical preparation protocols, such Pauli errors can be “pushed” to the end of the computation, where they combine into a single, well-defined error affecting the final state. The new technique also leverages the structure of these protocols to remove the most difficult elements to simulate, so-called non-Clifford operations, without changing the protocol’s overall outcome.
Existing simulation methods can precisely model only preparation protocols involving a few logical qubits and not the ones involving tens of logical qubits that are expected to produce the most reliable logical magic states. By contrast, the technique developed by Surti and his colleagues can be successfully applied to those large-scale protocols. The new approach could thus help scientists devise efficient protocols that would decrease the daunting resource costs associated with building a practical fault-tolerant quantum computer.
–Ryan Wilkinson
Ryan Wilkinson is a Corresponding Editor for Physics Magazine based in Durham, UK.
References
- S. Surti et al., “Efficient simulation of logical magic state preparation protocols,” PRX Quantum (2026).