London School of Economics professor, Trinity researcher rethink Heisenberg's uncertainty principle

One of the authors of a recent article offering a new perspective on the Heisenberg uncertainty principle said he hopes his colleagues will be cautious about how they approach this realm of quantum mechanics.

There's more to the idea than immediately meets the eye, London School of Economics & Political Science professor Bryan W. Roberts said during a Current Science Daily email interview.

"We hope colleagues might take away a little caution about a common folklore: time-energy uncertainty does not mean energy is not locally conserved — it is! — and it is not responsible for the creation of particles, virtual or otherwise," Roberts said. "The interpretation of time-energy uncertainty and of virtual particles is therefore subtle.

Roberts co-wrote the article "Time-energy uncertainty does not create particles" with Trinity College senior research fellow Jeremy Butterfield. The article was released July 6.

Roberts is "a philosopher of physics, associate professor of philosophy, logic and scientific method" at the London School, where he teaches philosophy, logic and the scientific method, according to his bio at the school.

Roberts and Butterfield's article provides a fresh look at a widely accepted interpretation of the Heisenberg uncertainty principle in quantum physics, a principle also known as the "time-energy uncertainty," as it's referred to in the article. That principle suggests that the precise position and speed of an object cannot be known because changing an object's position will change its speed, as changing an object's speed will also change its position.  

The principle has gained widespread acceptance among physicists because it resolves experimental observations about the origin of the universe without having to factor in a creation event.

Roberts' and Butterfield's article criticizes "many expositions" that the principle "that allows both a violation of energy conservation" but does "agree that there are grains of truth in these claims." 

Roberts and Butterfield also argue in their article that they "make precise" the grains of truth in those claims and "justify" them using perturbation theory, which allows finding a solution.

"One of the central postulates of quantum theory is that change in a local isolated system is unitary," Roberts said during his Current Science Daily interview. "Energy conservation is simply guaranteed in that regime. The interpretation of time-energy uncertainty, and of virtual particles, is therefore more subtle."

The paper was written in honor of the late Paul Busch, a longtime physicist at the University of York, according the paper's abstract. Busch's work is cited extensively throughout the article.

"To conclude, we hope to have shown that with a little Buschian wisdom, one can recover some grains of truth from some cavalier statements in the textbook tradition," the article said. "May Paul's legacy continue to inspire our community to emulate his craftsmanship and creativity."