Magic-Sates New Unlock

In the second week of January 2024, IBM Research published an article in Nature Journal titled 'Encoding a Magic State with Beyond Break-Even Fidelity. https://www.nature.com/articles/s41586-023-06846-3

This publication highlights the advancement in quantum hardware sensitivity, particularly in overcoming the constraints of circuit depth, a common limitation in current quantum computing. This development suggests the potential for high-fidelity quantum computers with a relatively small number of physical qubits. The key lies in the preparation of 'magic states' using adaptive, or dynamic, circuits.

For those new to quantum computing, it's important to differentiate this from the usual state preparation in quantum circuits familiar from platforms like Qiskit or Cirq. These conventional circuits employ gates such as Hadamard, CNot, or X, known as Clifford gates. According to researchers Bravyi and Kitaev, these gates have limited capabilities. However, they are useful for providing physical interpretations through Qiskit's sampler and Estimator runtime, based on error mitigation methods. These methods reduce, but do not prevent, errors, limiting the utility of increased qubit numbers. Thus, when running a quantum algorithm, one must select a server capable of handling the specified number of qubits.

The IBM article introduces an advanced error mitigation method using error correction, which obviates the need to deal solely with physical qubits. The error correction process involves two main stages: encoding the quantum information to identify the correct errors, and then manipulating this information, a process that uses a set of operations called logical gates. As this second stage is resource-intensive, IBM has developed 'Magic State Distillation.' This method potentially allows the selection of a single, most crucial quantum state for processing, rather than undertaking the entire manipulation process