Spooky influences might leap not just across space, but across time, too.
The mysteries of quantum mechanics are usually portrayed as mysteries of space: how strange that the fates of particles on opposite sides of the universe could be joined. But they are also mysteries of time. A particle you create today could be connected in some unaccountable way to one that does not exist yet. Einstein […]
Short answer: It’s largely a self-reinforcing expectation.
Every area of journalism presents its challenges, but quantum physics is in a molecular orbital of its own. It demands more time per word than anything else I’ve written about. Why is that? Earlier this month I offered some thoughts to fellow science journalists attending a philosophy-of-physics workshop at the University of Leeds. Although my […]
As strange as quantum entanglement is, the world would have been even stranger without it.
It’s quite a trick to picture a theory even weirder than quantum mechanics. Yet many physicists think the best way to make sense of quantum mechanics is to imagine what might have been. Within a vast radiation of conceivable theories, they look for principles that single out the quantum. In so doing, they aim to […]
To test the interpretation of quantum mechanics, look to cosmology.
Quantum physicists do love their beer. By day they build instruments, measure numbers, solve equations. By night they retire to the bar or pub and muse about the philosophical puzzles of quantum theory. By “philosophical” they mean “fun but impractical.” Maybe quantum theory betrays the existence of parallel universes, maybe it exposes causal influences coming […]
Thumb your noise at government surveillance with a highly simplified form of quantum cryptography.
“Are you telling me that this could be of practical use?” exclaimed the Irish physicist John Bell. He had shown in the 1960s that quantum entanglement burrowed deep into the foundations of physics, but even he hadn’t thought it could have real-world applications. That was the brainstorm of Artur Ekert, then a graduate student at […]
Here’s a talk I gave at the Centre for Quantum Technologies in Singapore on March 24, 2016. Note that it was the first time I’d given this particular talk and it had a couple of first-iteration glitches.
Shine a laser on a nonlinear optical crystal to get streams of entangled photons.
The number-one question that people ask me when I talk about nonlocality is: how are entangled particles created? I didn’t say much about this in the first edition of my book because the details don’t matter for my overall argument, but since everyone wants to know, I figure I should elaborate. (I’ve also added an […]
The debate over quantum nonlocality awaits its resolution in a unified theory of physics.
If anyone is the Kissinger of quantum physics—in a good way, striving to forge peace in the century-old dispute over the meaning of the quantum—it is Howard Wiseman. A theoretical physicist at Griffith University in Brisbane, Australia, Wiseman thinks the debate hasn’t been resolved because it can’t be, given our present state of knowledge. Only […]
The eminent Israeli physicist explains the peculiar type of action at a distance that bears his name.
In 1959 physicists Yakir Aharonov and David Bohm startled their colleagues by predicting a new type of quantum nonlocality, distinct from the phenomenon that had spooked Einstein. They showed that an electric or magnetic field can have an effect on a particle at a distance: even when the field exerts no force on that particle, […]
How quantum correlations transcend space and time.
The great mystery of quantum mechanics is that particles can be connected without a connector. They can coordinate their behavior in ways that are too complicated to be preprogrammed into them, even though no process is acting across the distance between them. “We can’t say that one thing led to another,” Nicolas Gisin of the […]
Einstein's underappreciated argument for the strangeness of quantum physics.
“This onslaught came down on us as a bolt from the blue,” recalled Léon Rosenfeld, a young colleague of the physicist Niels Bohr. They were shocked, shocked, by Einstein’s famous 1935 critique of their interpretation of quantum mechanics. But why the surprise? Einstein’s argument did not originate in 1935 or even with his storied confrontation […]
By thinking of nature as a hierarchy, scientists dissolve the dichotomies they have wrestled with.
Is the universe deterministic or indeterministic? A clockwork or a craps table? In this month’s issue of Scientific American, I have an essay arguing that the answer is: both. The world can be deterministic on some levels and indeterministic on others; these two categories are not mutually exclusive. To me, this is the essence of […]
Gravity might muck with the quantum by distorting the uncertainty principle and introducing ambiguities in sequences of cause and effect.
Conventional wisdom has it that putting the words “quantum gravity” and “experiment” in the same sentence is like bringing matter into contact with antimatter. All you get is a big explosion; the two just don’t go together. The distinctively quantum features of gravity only show up in extreme settings such as the belly of a […]
A metaphorical version of John Bell’s famous entanglement.
Simply put, bottomlessly deep: that is the definition of a great discovery in science. From the principle of relativity to evolution by natural selection, the concepts that govern our world are actually not that hard to state. What they mean and what they imply—well, that’s another matter. And so it is with quantum entanglement. One […]
Philandering spouses and students playing hookey, beware: quantum cryptography may make it impossible for you to hide your location.
SINGAPORE—When a speaker brings a tangle of garden hoses, a bottle of water, and a towel to the podium, you know it’s going to be a fun talk. Computer scientist Harry Buhrman of the Centrum Wiksunde & Informatica in Amsterdam recently visited Singapore to help celebrate the fourth anniversary of the Centre for Quantum Technologies. […]
A box can contain all the properties of a particle, even though no particle is there.
COPENHAGEN—Just when you thought you’d heard every quantum mystery that was possible, out pops another one. Jeff Tollaksen mentioned it in passing during his talk at the recent Foundation Questions Institute conference. Probably Tollaksen assumed we’d all heard it before. After all, his graduate advisor, Yakir Aharonov—who has made an illustrious career of poking the […]
Just when you thought the debates over free will couldn’t get any weirder.
COPENHAGEN—The late philosopher Robert Nozick, talking about the deep question of why there is something rather than nothing, quipped: “Someone who proposes a non-strange answer shows he didn’t understand the question.” So, when Scott Aaronson began a talk three weeks ago by saying it would be “the looniest talk I’ve ever given,” it was a […]
An experiment that used to fill a basement lab now fits on an endtable.
DRESDEN, Germany—How cool would it be not just to read about the craziness of quantum mechanics, but to see it—even better, do it—for yourself? Several years ago I asked virtuoso experimental physicist Paul Kwiat whether he could develop a simple demonstration anyone could do at home, and he and his undergraduate student Rachel Killmer came […]