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Einstein’s theory implies a “block universe” in which the passage of time is an illusion. Though this timeless view of reality remains popular, it’s hard to square with quantum mechanics, creating one of the biggest mysteries in physics. (Thread) https://www.quantamagazine.org/does-time-really-flow-new-clues-come-from-a-century-old-approach-to-math-20200407/
Physicists have long debated the validity of the block-universe version of reality. Time appears to pass, but things get trickier when we step back and ask why we happen to live in a universe where such a law holds. https://www.quantamagazine.org/a-debate-over-the-physics-of-time-20160719/
In 2018, when Quanta writers and editors reflected on the nature of time in the universe in a live panel, senior writer @nattyover called it “the big mystery of physics” due to its connection to other major open questions in the field.
The Swiss physicist Nicolas Gisin reasons that the problem all along has been mathematical. The answer, he argues, lies in intuitionist mathematics, a century-old mathematical language that rejects the existence of numbers with infinitely many digits.
“I am a physicist who has my feet on the ground,” Gisin said. “Time passes; we all know that.”
Intuitionist mathematics, championed by the Dutch topologist L.E.J. Brouwer, holds that that numbers with infinite digits aren’t real. Rather, precision must get created in a “choice sequence.” Gisin sees a connection to the physical notion of time in the universe.
Quantum mechanics is often said to imply that information can never be created or destroyed. Gisin “absolutely” rejects that notion, largely because “there is clearly new information that is created during a measurement process.”
Gisin’s ideas, bolstered by a mathematical language that could “liberate physicists from infinite precision,” resonate in many corners but still need to be fleshed out. For now, he plans to keep thinking.
For more on this story and for ongoing reporting in physics, biology, mathematics, computer science and more, visit http://quantamagazine.org (/thread)
