Through Two Doors at Once: The Elegant Experiment That Captures the Enigma of Our Quantum Reality

by Anil Ananthaswamy

I will not describe it in terms of an analogy with something familiar. I’ll simply describe it.”

When asked about the usefulness of such waves, Hertz reportedly said, “It is of no use whatsoever.

Taken at its most extreme, the Copenhagen interpretation is anti-realist: it denies any notion of reality that exists independent of observation. More important, the proponents were claiming that the mathematical formalism is complete, and that there is nothing more to say about reality.

reality does not exist in any meaningful sense independent of measurement with a classical apparatus.

By 1980, I had a fantastic source of entangled photons.

it was not possible to formulate the laws of quantum mechanics in a fully consistent way without reference to the consciousness.”

The events at Tenerife, in our usual way of thinking, happen later in time, yet still influence the outcome of measurements at La Palma,

Is the wavefunction ontic (meaning it is something) or is it epistemic (in that the wavefunction represents our knowledge about something);

“This is the latest in the long line of epic human intellectual follies that have resulted from man putting himself at the center of the universe,”

“Literary modernism was supposed to be a response to the crisis of representation in literature. Physics wanted to have its crisis of representation too,”

A university student attending lectures on general relativity in the morning and . . . on quantum mechanics in the afternoon, might be forgiven for concluding that his professors are fools, or they haven’t talked to each other for at least a century.

a stable form of carbon that had been identified in 1985 and named buckminsterfullerene, or buckyball, because it has the segmented 3-D shape of the geodesic dome invented by Buckminster Fuller.

it gets more and more counterintuitive, at least psychologically, if things become bigger and bigger and more complex internally.

if experiments like his never see collapse, even as the macroscopic objects in superposition keep getting bigger and bigger, that’s a sign. “In that case I am really going to take the many worlds interpretation seriously,”

“One can imagine an intelligent amoeba with a good memory. As time progresses the amoeba is constantly splitting, each time the resulting amoebas having the same memories as the parent.

His iPhone has an app called the Universe Splitter, which is a version of the watch that Vaidman wanted to patent—one that will help you make up your mind when confronted with a difficult YES or NO decision.

the idea of new branches of the wavefunction and hence new worlds appearing at every quantum fork in the road. “There is a heavy psychological price to pay, and the question is, how much does that bother you?” said Carroll. “Doesn’t bother me at all.”

the parallel universes are cheap on assumptions but expensive on universes?”

There is always a period of time in which the branching has occurred and there are two copies of you, but those two copies are exactly the same, because they don’t know what branch they are on yet,”

either that the wavefunction represents our knowledge of the quantum system, so it is epistemic, and theories that take this stance are called psi-epistemic; or that the wavefunction is part of reality itself, and theories of this persuasion are called psi-ontic

correlations that imply instantaneous action at a distance between, say, Alice’s measurements and Bob’s photons, or vice versa.