NIST researchers have developed a powerful method to suppress errors in quantum computers using an array of 1,000 ultracold beryllium ions. The technique, demonstrated in Nature, counteracts random errors caused by environmental disturbances by applying customized microwave pulses to reverse error accumulation in all qubits simultaneously. Simulations show this method can reduce error rates up to 100 times more than comparable techniques, and the results validate these predictions.
The new error-suppression method could enable quantum computers of various designs to achieve error rates far below the fault-tolerance threshold of 0.01%, making practical quantum computers more realistic. Quantum computers could someday break encryption codes, perform faster searches of large databases, and determine efficient schedules for complex systems. However, building practical quantum computers requires reliable components, and the NIST method is an adaptation of “spin echo” techniques used to suppress errors in nuclear magnetic resonance.
The NIST team conducted the first experimental demonstration of a theory to modify pulse timing for improved noise suppression, and extended these ideas by generating novel pulse sequences tailored to ambient noise environments. These sequences can be found quickly through experimental feedback and significantly outperform other sequences without needing knowledge of noise characteristics. The research was conducted in the laboratory of NIST physicist John J. Bollinger and funded in part by the Intelligence Advanced Research Projects Activity.
Keywords: qubits, quantum computers, error suppression
