Physicists from the Vienna Technological University have made a groundbreaking discovery that could set a limit on the performance of large-scale quantum computers. The discovery revolves around the method of measuring time at a fundamental level. While this may not seem relevant now, the future development of practical quantum computing relies on our ability to accurately measure time, which is predicted to become increasingly challenging.
One of the restrictions identified is the resolution at which time can be divided. Measurements of any event shorter than 5.39 x 10^-44 seconds contradict theories about the basic functions of the Universe. Furthermore, physicists believe that additional costs are incurred when measuring smaller increments of time.
Marcus Hubert, the leading author of the study and head of the quantum information group and quantum thermodynamics, explains that the measurement of time is intricately connected to entropy. In their recent theorem, Hubert and his team demonstrate that any rapidly ticking clock will eventually encounter accuracy problems unless supplied with an infinite amount of energy. Theoretical physicist Florian Mayer adds, “This means that either the clock works quickly or with certainty – both options are simultaneously impossible.”
While this may not pose a significant problem for regular time measurement, it is critical for technologies like quantum computing where timing is crucial. As the number of quantum particles increases, the risk of them exiting the quantum-critical state also increases, leaving less time for the necessary calculations.
While the accuracy of quantum computers is already limited by other factors, such as the precision of their components, this study reveals that we are nearing a stage where fundamental limitations on time measurement will become decisive. Although future advancements in quantum computing may enhance stability and reduce errors, the question remains whether entropy will ultimately define the limits of quantum computing power.
The study has been published in the journal Physical Review Letters.