Amerika

The problem with having a big brain: it gets hard to tell what you’ve observed, or simply thought you observed, because your brain contains so many memories and predictions of the world.

“HOW wonderful that we have met with a paradox. Now we have some hope of making progress.” So said Niels Bohr, one of the founders of quantum mechanics. Since its birth in the 1920s, physicists and philosophers have grappled with the bizarre consequences that his theory has for reality, including the fundamental truth that it is impossible to know everything about the world and, in fact, whether it really exists at all when it is not being observed. Now two groups of physicists, working independently, have demonstrated that nature is indeed real when unobserved. When no one is peeking, however, it acts in a really odd way.

The reality in question—admittedly rather a small part of the universe—was the polarisation of pairs of photons, the particles of which light is made. The state of one of these photons was inextricably linked with that of the other through a process known as quantum entanglement. Drs Yokota, Lundeen and Steinberg managed to observe them without looking, as it were, by not gathering enough information from any one interaction to draw a conclusion, and then pooling these partial results so that the total became meaningful.

What the several researchers found was that there were more photons in some places than there should have been and fewer in others. The stunning result, though, was that in some places the number of photons was actually less than zero. Fewer than zero particles being present usually means that you have antiparticles instead. But there is no such thing as an antiphoton (photons are their own antiparticles, and are pure energy in any case), so that cannot apply here.

The Economist

Was this a case of us not knowing how to predict where things should be?

An interesting perspective:

a sizeable minority of physicists have long been pushing entirely the opposite view. They remain unconvinced that quantum theory depends on pure chance, and they shun the philosophical contortions of quantum weirdness. The world is not inherently random, they say, it only appears that way. Their response has been to develop quantum models that are deterministic, and that describe a world that has “objective” properties, whether or not we measure them. The problem is that such models have had flaws that many physicists consider fatal, such as inconsistencies with established theories.

Until now, that is. A series of recent papers show that the idea of a deterministic and objective universe is alive and kicking. At the very least, the notion that quantum theory put the nail in the coffin of determinism has been wildly overstated, says physicist Sheldon Goldstein of Rutgers University in New Jersey. He and a cadre of like-minded physicists have been pursuing an alternative quantum theory known as Bohmian mechanics, in which particles follow precise trajectories or paths through space and time, and the future is perfectly predictable from the past. “It’s a reformulation of quantum theory that is not at all congenial to supposedly deep quantum philosophy,” says Goldstein. “It’s precise and objective – and deterministic.”

If these researchers can convince their peers, most of whom remain sceptical, it would be a big step towards rebuilding the universe as Einstein wanted, one in which “God does not play dice”.

In the early 1950s, physicist David Bohm developed a more consistent version of the pilot-wave model, one based on the same equations as ordinary quantum theory but offering a different interpretation of them. Bohm found buried within those equations a close link to the mathematics of classical physics, which is based on Newton’s laws of motion. Bohmian mechanics asserts that the outcome of an experiment isn’t truly random, but is determined by the values of certain “hidden variables”. For instance, in quantum theory two electrons may be “entangled” such that their states appear to have a kind of spooky link; measuring the spin of one determines the spin of the other, say. Bohm’s theory suggests that they share a hidden variable governing spin. The theory also shows how probabilistic quantum measurements can always arise from specific particle trajectories.

NewScientist

We have a universe with infinite factors.

We pick one factor, compare before and after, and use that to determine cause, when cause is a collaboration of many different factors.

We discard all other facts, and call them “details” or “context,” implying they are not valid — yet mathematically speaking, the world appears as a consistent whole because of the interaction of many factors (called parallelism). We cannot discard details because they are part of the structure of the multiple factors causally interacting.

It may be the origin of perspective bias, this tendency of ours to semi-arbitrarily classify some things as “actors” and others as “details” or “background noise.”

When the world does not reward our linear model, we blame it for being inconsistent, and invent radical quantum theories to explain what classical physics might — but that we may simply not have enough information, or the attention span, to see exists.

This is relativity versus relativism.

Relativity: As Schopenhauer and the Hindus told us many years ago, the universe is relative, because no part exists in a vacuum. One object needs another to act upon for the first object to have any property; the difference between states and objects is what gives them meaning. Colors, for example, are a result of reflected light, not an inherent “color” attribute of the object. Without light, it would have no color.

Relativism: making excuses for our own perception, or that of others, in a rigid literalist physics that assumes all reality succumbs to a few rules of appearance. In short, perspective bias.