22 Quotes by Philip Ball

Here is the answer to Einstein’s question about the moon. Yes, it is there when no one observes it – because the environment is already, and without cease, ‘measuring’ it. All of the photons of sunlight that bounce off the moon are agents of decoherence, and more than adequate to fix its position in space and give it a sharp outline. The universe is always looking.

[Q]uantum physics is not replaced by another sort of physics at large scales. It actually gives rise to classical physics. Our everyday, commonsense reality is, in this view, simply what quantum mechanics looks like when you’re six feet tall.

The sustaining interest and enthusiasm of many friends and colleagues are, of course, the nutrition that every writer needs, and can never adequately acknowledge.

The wavefunction tells us where we might potentially find an electron when we look; but what we do find in any given experiment is random, and we can’t meaningfully say why we find it here rather than there.

[W]hereas we might have been content enough to believe that electrons in a bright beam are wave-like and can be diffracted by the double slits, it is hard to understand how one-by-one passage of what seem to be particles (judging from the discrete bright spots that appear on the screen) can produce wave-like interference. We’re forced to conclude that ‘wave-like’ electrons can interfere with themselves.

[A]tomic nuclei are pretty hard to peer into. But that’s not the root of the problem. It’s that we simply can’t, for quantum processes, talk about a historical progression of events that led to a given outcome. There’s no story of how it ‘got’ to be that way.

Wavefunction collapse is a generator of knowledge: it is not so much a process that gives us the answers, but is the process by which answers are created. The outcome of that process can’t, in general, be predicted with certainty, but quantum mechanics gives us a method for calculating the probabilities of particular outcomes. That’s all we can ask for.

The combination of random branching and orderly underlying lattice creates the exquisite complexity of the snowflake, poised on the brink of chaos and minutely sensitive to tiny variations in the temperature and humidity of the air.

We know that measurements of a quantum system seem to collapse the wavefunction. We most certainly don’t know how, or why, or indeed if that actually happens.