Critical Opalescence
A blog about cutting-edge physics

Physicists Look Beyond the Large Hadron Collider, to the Very Large Hadron Collider

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 […]

Gravitational Waves Reveal the Universe before the Big Bang: An Interview with Physicist Gabriele Veneziano

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 […]

What Happens to Google Maps When Tectonic Plates Move?

Consumer GPS now achieves an accuracy of a few meters, good enough to spot mapping errors and geological changes.

A couple of weeks ago, I was writing up a description of Einstein’s general theory of relativity, and I thought I’d compare the warping of spacetime to the motion of Earth’s tectonic plates. Nothing on Earth’s surface has fixed coordinates, because the surface is ever-shifting. Same goes for spacetime. But then it struck me: if […]

The Wholeness of Quantum Reality: An Interview with Physicist Basil Hiley

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 […]

Does Some Deeper Level of Physics Underlie Quantum Mechanics? An Interview with Nobelist Gerard ’t Hooft

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 […]

When the Large Hadron Collider Is Too Small

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 Would It Mean for Time to Come to an End? [Video]

A TEDx talk in 2013

Could time come to an end? What would that even mean? In April 2013 I gave a talk about this strange physics idea at a TEDx event in Trento, Italy, based on a Scientific American article I wrote in 2010. My conceit was that time’s end poses a paradox that might be resolved if time […]

George and John's Excellent Adventures in Quantum Entanglement, Part 2 [Video]

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 […]

How to Build Your Own Quantum Entanglement Experiment, Part 2 (of 2)

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 […]

How to Build Your Own Quantum Entanglement Experiment, Part 1 (of 2)

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 […]

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