Researchers at NIST / University of Maryland and Duke University recently used a closed quantum computer to detect two quantum phases caused by measurement, the purest phase and the mixed-phase or coding phase during the phase-shifting phase. Their findings, published in a paper in Nature Physics, contribute to the practical understanding of many quantum body systems.
“Our methods were based on the work of Michael Gullans and David Huse, who identified purification changes caused by measurement in random quantum circuits,” Crystal Noel, one of the researchers who conducted the study, told Phys.org. “The main purpose of our paper was to investigate this critical situation, using a quantum computer.”
To measure the change in the cleaning phase mentioned by Gullans and Huse, the researchers had to measure the data collected in a few random circuits. In addition, the estimates they collected included both aggregated estimates and estimates.
“Starting in a mixed situation with high entropy, or knowledge, and then switching circuits, entropy at the end of the circuit indicates that information is lost, or in other words the system is cleared,” explains Noel. “We measured the entropy of the system after the emergence of the region as we adjust the measurement rate throughout the change.”
According to theoretical predictions, the clean-up of the clean-up phase investigated by the team had to come from a critical area, such as the tolerance limit. Noel and his colleagues have researched random circuits developed to work effectively with their ion-trap quantum computer. This allowed them to see different stages of purification using a relatively small system.
“Critical situations of this nature are difficult to detect due to the need for larger system sizes, mid-circuit measurements, and averages in many random circuits that take up significant calculation time,” Noel said. “We found a way to integrate the model we learned into the program we had, and to show that with a smaller model, critical issues can still be identified.”