Time After Time

In the here and now, one might argue I am on the verge of missing my deadline and turning this column in late. On the bright side, in some other universe, some other version of me is on task and has not wasted crucial minutes changing the cat's litter box and watching a video of Lady Gaga serenading Elton John. And since this is a hypothetical scenario, that version of me isn't wearing Hello Kitty pajamas and her hair is, you know, brushed.

I am using the Many Worlds notion to justify this particularly ragged Monday morning, but for physicists, accepting this theory could be key to making progress both in quantum mechanics and the field of physics overall.

So says theoretical physicist Sean Carroll, a research professor of Physics at Caltech, whose forthcoming book, Something Deeply Hidden, examines what he characterizes as a crisis in the field of physics.

"It's a sort of hidden crisis," Carroll says. Quantum mechanics theory, he continues, "came together in the early part of the 20^th century, and it's mysterious, it's weird, and it especially troubles us because it makes it sound like the act of observing something plays an important role in the nature of physical reality." This, he notes, "is surprising from everything else we previously knew." Nonetheless, the theory "works really well at making predictions, and therefore physicists for the last 90 years have basically ignored the question of what … quantum mechanics really says. I think that's terrible and I think it's holding us back from making progress in physics."

Carroll will be part of the Time Panel at the Santa Fe Institute's June 14-16 Interplanetary Festival (https://interplanetaryfest.org), discussing the nature of time with molecular biologist Coleen Murphy and chef Mark Miller, founder of the Coyote Café. As a physicist, Carroll will discuss "where time comes from, what it is, and how it works." Murphy "studies aging and how biological organisms change over time." Miller will converse on the role of time in food, which Carroll describes as "crucial and under-appreciated … both the act of making the food and eating and enjoying it." Overall, Carroll says, "I'm hoping we have a broad, interdisciplinary conversation."

Carroll's work isn't confined to other planets; he's concerned with other universes. Quantum mechanics laws govern how photons and electrons, as well as other particles, work. The Many Worlds interpretation of quantum mechanics posits that each time a quantum event happens, all the outcomes occur and there are, thus, multiple versions of us, and the world, in the universe.

Carroll describes the Many Worlds theory as "the best theory in quantum." For one, he notes, "it's the simplest. It's not the case where someone took quantum mechanics and added a bunch of worlds to it. Every other approach to quantum mechanics has to get rid of it." Accepting the theory, he says, would allow physicists "to say with more confidence how reality worked at a fundamental level." And "it might help us with gravity and spacetime and how those fit into a quantum mechanical picture."

Spacetime, another topic in Carroll's forthcoming book, refers to the theory that rather than looking at space and time separately, "we should think of them together as one four-dimensional space time," aka Albert Einstein's theory of relatively.

Einstein, Carroll notes, "said not only is spacetime one big four-dimensional thing, but it has a life of its own: it has dynamics, it can change. It responds to energy and gets curved, gets warped, and we experience that curvature as gravity." Therefore, "the nature of spacetime is at the heart of trying to understand gravity."

Physics has been reluctant to push forward in the area of quantum mechanics, Carroll says, but doing so will further progress in understanding quantum gravity and other key areas in the field.

Still, he's aware that accepting the Many Worlds theory has "some bizarre consequences for how we think about ourselves: If I can observe a quantum particle and create a copy of myself, what does that mean for my self image and personal identity?"

On the other hand, "I think one of the reasons we have this power of imagination is the human imagination can allow us to imagine things we can't make happen in reality. Part of that is for fun, telling stories. Part of it is also stress testing the way we live in the actual world. What if things were very different? What if you could visit your past or go to the future? A panel like this is a great opportunity to test out our ideas in a wholly different context than we're used to."

See you there! Don't be late.

Time Panel
Interplanetary Festival
2:05 pm, June 16, Free
Main Stage, Santa Fe Railyard Park