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 […]
Entanglement is not the only type of nonlocality in quantum theory.
It stands to reason that electromagnetism is a theory of electric and magnetic fields. But since when is anything in physics so straightforward? Although Maxwell’s equations of electromagnetism in their usual formulation do contain electric and magnetic fields, those equations can be rewritten in terms of a mathematical function called the potential. So what is […]
The atoms of space may be tiny, but could have huge effects.
If spacetime is made of atoms, as many theoretical physicists these days speculate, could we ever know? You might doubt it. Conventional wisdom says those atoms would be too small, too energetic, or just plain too weird. But Daniele Oriti thinks we have a shot. Oriti, an Italian theorist working at the Max Planck Institute […]
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 […]
When physicists get stuck, call in the philosophers.
The nice thing about philosophers of physics is that they have no dog in the fight among string theory, loop quantum gravity, and other competing approaches to a fundamental theory of nature. They can stand back and offer some third-party perspective. One who specializes in this is Karen Crowther, a postdoc in the University of […]
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 […]
Step one to understand the mysteries of black holes: build a big bathtub.
Don’t be alarmed, but there is a black hole in your bathtub. When you drain the tub, water converges on the plughole and speeds up, eventually flowing too fast for surface waves to propagate outwards. Those waves get swept down the drain like hapless astronauts falling into a black hole (see video at end of […]
Black holes might be explosions occurring in extremely slow motion, says theoretical physicist Carlo Rovelli.
Theoretical physicist Carlo Rovelli, one of the creators of loop quantum gravity, and his collaborator Hal Haggard have just come out with a new paper on black holes. Ever attuned to puns, Rovelli calls it the “fireworks” model, alluding to the firewall argument that has consumed black-hole theorists over the past two years. As if […]
Now that the world’s premier particle smasher has reached its maximum energy, physicists are planning new machines to follow up its discoveries.
In 1954 the renowned physicist Enrico Fermi did a simple but depressing calculation about future particle accelerators. To create particles with an energy of 3 teraelectron-volts, he estimated, you’d have to build a ring 8,000 kilometers in radius at a cost of $170 billion. It was a rare instance of Fermi being wrong. The Large […]
The BICEP2 discovery of primordial gravitational waves was premature, but got theorists wondering about what came before the big bang.
It’s not usually put like this, but the discovery of primordial gravitational waves two weeks ago has given us our first direct glimpse of a period before the big bang. [The discovery was later retracted, but I’ll keep this post here to show why theorists at the time found it so exciting.] The term “big […]
David Bohm's longtime collaborator explains why he thinks quantum physics describes a holistic reality.
VIENNA—One night in 1952, Richard Feynman and David Bohm went bar-hopping in Belo Horizonte. Louisa Gilder reconstructs the night in her brilliant book on the history of quantum mechanics, The Age of Entanglement. Feynman was on a sabbatical in Rio and, ever exuberant, raved about local beers, drumming lessons, and Brazilian girls. Bohm, teaching at […]
Is the notorious randomness of quantum mechanics just a front?
VIENNA—Over the past several days, I attended a fascinating conference that explored an old idea of Einstein’s, one that was largely dismissed for decades: that quantum mechanics is not the root level of reality, but merely a hazy glimpse of something even deeper. A leading advocate is Gerard ’t Hooft of Utrecht University, who shared […]
Four times the circumference, seven times as much energy: Is that really what it’ll take to test multiverse theories?
The Large Hadron Collider has only just begun its explorations, so it might seem a little premature to begin thinking about what new particle projects might come next. But given how long these things take to plan, is it ever too soon? This summer, particle physicists held a huge planning retreat in Minneapolis, which Peter […]
What a great way to start the week: the Foundational Questions Institute has just announced its fifth essay contest. The topic is the physics of information. It could hardly be more timely, and not just because of the cultural Zeitgeist. Going to a physics conference these days is like landing in The Village of the […]
Here’s what an entanglement experiment actually looks like.
The first time I ever saw quantum entanglement for myself was in August 2011 on a road trip to Colgate University. Goodness knows how many blog posts and magazine articles have been written about the quantum realm, invariably describing it as weird. But I’d never actually seen this supposed mind-blowingness with my own eyes, which […]
The cheapest and easiest way to do the famous Einstein-Podolsky-Rosen experiment.
In my last post, I scrounged the parts for a very crude, but very cool, experiment you can do in your basement to demonstrate quantum entanglement. To my knowledge, it’s the cheapest and simplest such experiment ever done. It doesn’t give publishable results, but, to appropriate a line from Samuel Johnson, a homebrew entanglement experiment […]
The cheapest and easiest way to do the famous Einstein-Podolsky-Rosen experiment.
Quantum-entanglement experiments are not exactly something you can buy in the science kit aisle at Toys ’R Us. The cheapest kit I know of is a marvel of miniaturization, but still costs 20,000 euros. In the past month, though, I’ve put together a crude version for just a few hundred dollars. It’s unbelievably simple—so simple […]
Who’d have thought viscous fluids would act like gravitational waves caroming off a black hole?
The whole point of an explanation is to reduce something you don’t know to something you do. By that standard, you don’t gain much by explaining anything in terms of black holes. Appealing to the most mysterious objects known to science as an explanation sounds like using one mystery to explain another. Yet this is […]
Maybe not long at all, if black holes are ringed by “firewalls.”
In chatting with colleagues after a talk this week, Joe Polchinski said he’d love to fall into a black hole. Most theoretical physicists would. It’s not because they have some peculiar death wish or because science funding prospects are so dark these days. They are just insanely curious about what would happen. Black holes are […]
Quantum physics is becoming the next maker revolution.
For years I’ve been thinking and hoping that quantum physics would become the next hacker revolution. DIYers in their basements, garages, and hackerspaces have already pioneered radio communications, PCs, household robots, and cheap 3-D printers—why not quantum entanglement, cryptography, computers, and teleportation? In recent years, physics educators have streamlined quantum experiments to the point where […]
Foil tray, plastic tumbler, and rubbing alcohol make for a simple cloud chamber, without any dry ice.
In about 10 minutes, using stuff you probably already have lying around your house, you can watch atomic nuclei and elementary particles for yourself using a diffusion cloud chamber—a rudimentary particle detector. There are lots of websites and YouTube videos giving step-by-step instructions to build such a chamber, but all require some component that’s hard […]
Introducing a whole new breed of number, the p-adics.
Cosmologists have been thinking for years that our universe might be just one bubble amid countless bubbles floating in a formless void. And when they say “countless,” they really mean it. Those universes are damned hard to count. Angels on a pin are nothing to this. There’s no unambiguous way to count items in an […]
SANTA BARBARA—Someone once asked me to describe string theory in 26 seconds, so, a couple of months ago, I went down to Goleta Beach with my iPhone and recorded this little video. It’s kind of spacey, I admit. Soundtrack and dog were entirely unintentional.
Black holes are not just distant cosmic monsters. Microscopic ones may exist all around us, with potentially momentous consequences.
It may well have been the liveliest hour and a half I’ve ever spent in the company of theoretical physicists. In April, during a workshop I was attending on black holes, Bill Unruh gave a talk that challenged his colleagues on a point almost all of them thought had been settled in the mid-1980s. His […]
Start with a row of rubidium atoms, place your bets, let ’em go.
SINGAPORE—I’d heard of quantum dice, quantum poker, quantum roulette, and even quantum Russian roulette, but a quantum horse race? I learned about this surreal game of chance last December during a symposium at the Centre for Quantum Technologies in Singapore. Start with a row of rubidium atoms, place your bets, let ʼem go, and measure […]
Out in the cosmos, “dark accelerators” slingshot particles to huge speeds and no one knows why.
At a lecture I went to some years ago, astrophysicist Trevor Weekes compared garden-variety elementary particles to mosquitoes. They are plentiful and easy to find—indeed, they find you. But ultra-high-energy gamma rays, he said, are like elephants. They are fairly rare, but among the greatest of creatures. They often roam in spectacular habitats. Their sheer […]
There’s something unnerving about unifying physics. The two theories that need to be unified, quantum field theory and Einstein’s general theory of relativity, are both highly successful. Both make predictions good to as many decimal places as experimentalists can manage. Both are grounded in compelling principles. Both do have flaws — including an unfortunate tendency to […]