Physicists Identify Potential Performance Limitations for Large Quantum Computers

Posted by

(Dario Truco/Getty Images)

In a groundbreaking revelation, researchers from the Vienna University of Technology have unveiled a newfound compromise in the fundamental operations of time-keeping devices. This discovery could impose a formidable constraint on the efficiency of expansive quantum computing systems. The implications of this trade-off shed light on the challenges large-scale quantum computers may face, hinting at potential limitations in their overall performance.

Though not an urgent concern, the trajectory of transforming quantum prototypes in the backroom into formidable number-crunching powerhouses hinges on our ability to intricately divide our days. Researchers emphasize that as we aim for ever finer time divisions, the task becomes progressively more complex. This challenge underscores the critical role of precise time dissection in the evolution of practical quantum computing systems.

Whether you’re marking seconds with the hushed rhythm of “Mississippi” or segmenting them through the oscillation of an electron in atomic constraints, the quantification of time finds its boundaries within the inherent limits of physics. This journey into time measurement unveils the fascinating interplay between diverse methods, each tethered to the fundamental principles of the physical world.

One limitation to consider pertains to the precision in which time can be divided. Attempting to measure events shorter than 5.39 x 10-44 seconds clashes with fundamental theories governing the workings of the Universe, rendering such measurements nonsensical.

Even before reaching the strict boundary in the chronological landscape, physicists anticipate encountering a toll that might hinder our ability to measure increasingly minute units.

Inevitably, every timekeeping device eventually winds down. Whether it’s a slowing pendulum, a depleted battery, or the need for a reset in an atomic laser, the challenge extends beyond mere engineering intricacies. The progression of time itself reflects the Universe’s transition from a highly ordered state to a complex, entangled state known as entropy.

Senior author Marcus Huber explains that “Time measurement always has to do with entropy”.

In their recently released theorem, Huber and his research team outline the reasoning linking entropy as a thermodynamic phenomenon with resolution. They illustrate that unless there’s an infinite energy source at your disposal, a rapidly ticking clock will inevitably encounter challenges in precision.

theoretical physicist Florian Meier puts it, “That means: Either the clock works quickly or it works precisely – both are not possible at the same time.”

This may not pose a significant issue if you’re measuring out seconds that remain consistent over the entire lifespan of our Universe. However, for technologies like quantum computing, which depend on the delicate behavior of particles teetering on the brink of existence, precision in timing becomes crucial.

The challenge is more manageable when dealing with a small number of particles. However, as the particle count increases, the likelihood of any individual particle being disrupted from its quantum critical state grows, leaving progressively less time to execute the required computations.

Considerable research has delved into investigating the risk of errors in quantum technology arising from a universe that is inherently noisy and imperfect. This marks the inaugural instance where researchers have examined the fundamental physics of timekeeping as a potential hindrance.

“Currently, the accuracy of quantum computers is still limited by other factors, for example the precision of the components used or electromagnetic fields,” says Huber.

“But our calculations also show that today we are not far from the regime in which the fundamental limits of time measurement play the decisive role.”

There’s a good chance that further enhancements in quantum computing will enhance stability, minimize errors, and extend the operational efficiency of scaled-up devices. However, the ultimate impact of entropy on the potential capabilities of quantum computers remains uncertain, and only time will reveal the final verdict.

This research was featured in Physical Review Letters.