Scientists Focus on Understanding Source of Noise--A Major Issue in Quantum Computing
Washington, D.C.–December 22, 2023. In a recent paper published in Physical Review Letters, Universities Space Research Association's Filip Wudarski and his team showed that understanding the source of noise is of primary importance for quantum computers.
The paper discusses how scientists can study the specific features of low-frequency noise in a quantum bit (qubit) using relatively short measurements. These measurements are shorter than the time it takes for the noise source to explore all its possible states, and thus reach the ergodic limit.
Nonergodic measurements provide a snapshot of the noise source's distribution across its states with the information usually averaged out in long measurements. Therefore, nonergodic measurements are sensitive to both the origin of the noise and the parameters of the noise source. This sensitivity is especially noticeable when dealing with noise from two-level systems, which are considered a significant cause of low-frequency noise in qubits.
The paper also reveals that the transition to a quasi-ergodic limit (a state where the system behaves similarly to an ergodic system) can happen before the noise source explores all its states. This transition can strongly depend on how the measurements are conducted.
Additional Resources: (https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.230201).
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