“Atoms” of space are too small to see, but betray themselves indirectly.
I’m fascinated by how the humblest observations can lead you to the profoundest conclusions, and here’s one I learned from Thanu Padmanabhan, an eminent theoretical physicist at the Inter-University Centre for Astronomy and Astrophysics in Pune, India. Suppose you cup your hands around a glass of cold water to warm it up. From this simple […]
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 […]
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 […]
A simple model of the phase transition that begat space.
Could space as we know it be just one possible phase of the universe, able to undergo a transition to or from an entirely alien structure? This video animation shows how that might happen, according to a model known as quantum graphity, developed by theoretical physicists Tomasz Konopka, Fotini Markopoulou, Lee Smolin, and others. (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 […]
The holographic principle, as explained by the man who has done more than anyone else to understand it.
The holographic principle is arguably the most tangible and tantalizing clue to a quantum theory of gravity, but for years physicists didn’t know what to make of it. That changed in 1997 when Juan Maldacena, now at the Institute for Advanced Study, came up with the first concrete example of what the principle means and […]
A leading theorist explains quantum entanglement and what it might mean for the structure of spacetime.
Some of the most interesting conversations I’ve had in my life have been with Ted Jacobson, a theoretical physicist at the University of Maryland. A musician, an amateur baker, and co-creator of loop quantum gravity, he is deeply self-reflective—a man who always questions his own thinking, who used to criticize string theory but then came […]
Spacetime seems to have a granular structure, but what the heck are the grains?
Joe Polchinski, based at the Kavli Institute for Theoretical Physics in Santa Barbara, is one of the world’s leading string theorists and an avid cyclist. (Many colleagues have challenged him to a race, to their later chagrin.) He is best known for showing that string theory isn’t just about strings—it predicts a huge diversity of […]
Spacetime derives from a deeper quantum reality, suggests the U.C. Santa Barbara theoretical physicist.
One of the scientists I follow in my book is Steve Giddings, a theoretical physicist at U.C. Santa Barbara who is also a highly skilled mountain-climber. In this video, he explains how quantum mechanics, when applied to black holes, calls the principle of locality into question and suggests that spacetime is not a fundamental ingredient […]