Quantum computing: Logical gates with magic state distillation

Let the magic of quantum computing begin with an improved error correction method!

"Today, one of the biggest challenges facing the field of quantum computation is protecting extremely sensitive quantum hardware from the errors that result from noise in order to run utility-scale circuits ...
In our new paper, we demonstrated a new procedure to encode magic states onto four qubits of the 27-qubit IBM Falcon processor on the ibm_peekskill system. ...
Basically, we can create more magic states and less junk. ...
It also sets us on the path to solving one of the most important challenges in quantum computing — running high-fidelity logical gates on error-corrected qubits. ..."

From the abstract:

"To run large-scale algorithms on a quantum computer, error-correcting codes must be able to perform a fundamental set of operations, called logic gates, while isolating the encoded information from noise. We can complete a universal set of logic gates by producing special resources called magic states. It is therefore important to produce high-fidelity magic states to conduct algorithms while introducing a minimal amount of noise to the computation. Here we propose and implement a scheme to prepare a magic state on a superconducting qubit array using error correction. We find that our scheme produces better magic states than those that can be prepared using the individual qubits of the device. This demonstrates a fundamental principle of fault-tolerant quantum computing, namely, that we can use error correction to improve the quality of logic gates with noisy qubits. Moreover, we show that the yield of magic states can be increased using adaptive circuits, in which the circuit elements are changed depending on the outcome of mid-circuit measurements. This demonstrates an essential capability needed for many error-correction subroutines. We believe that our prototype will be invaluable in the future as it can reduce the number of physical qubits needed to produce high-fidelity magic states in large-scale quantum-computing architectures."

Logical gates with magic state distillation | IBM Research Blog Some of the most important problems for quantum computers require running very, very long circuits: those with 100s or 1,000s of qubits and depths of 109 - 1011. The way we run those circuits is with error correction, methods protecting qubits from noise and errors.

Encoding a magic state with beyond break-even fidelity (open access)

Extended Data Fig. 1: A generic magic-state distillation protocol. (Looks like a classical tree diagram to me! 😊)