They use these six entangled photons to create two alternate realities—one representing Wigner and one representing Wigner’s friend. Wigner’s friend measures the polarization of a photon and stores the result. Wigner then performs an interference measurement to determine if the measurement and the photon are in a superposition.

The experiment produces an unambiguous result. It turns out that both realities can coexist even though they produce irreconcilable outcomes, just as Wigner predicted.  

That raises some fascinating questions that are forcing physicists to reconsider the nature of reality.

The idea that observers can ultimately reconcile their measurements of some kind of fundamental reality is based on several assumptions. The first is that universal facts actually exist and that observers can agree on them.

But there are other assumptions too. One is that observers have the freedom to make whatever observations they want. And another is that the choices one observer makes do not influence the choices other observers make—an assumption that physicists call locality.

If there is an objective reality that everyone can agree on, then these assumptions all hold.

But Proietti and co’s result suggests that objective reality does not exist. In other words, the experiment suggests that one or more of the assumptions—the idea that there is a reality we can agree on, the idea that we have freedom of choice, or the idea of locality—must be wrong.

Eoin Treacy's view

I apologise if this going to sound a little wonkish but there are important considerations raised that have a direct impact on the nature of markets and crowd psychology.

Every electrical engineer is taught that you change a system by measuring it. The change is obviously very small but there are phase modulations that occur when you interfere with the system to measure it. That is a clear fact.

At The Chart Seminar, I often talk a little about Heisenberg’s Uncertainty Principle which is that the more you know about the position of the particle the less you know about its velocity.

Then we have the above piece citing the assumption that the choices people make do not have an influence on the choices other make. In the markets we absolutely know that the choices other people make have a definite impact on the decisions of everyone who has yet to make a decision. We also know that the more a winning strategy is seen to work the greater the reliance investors place on it.

Buying the dips in Amazon has been one of the most effective strategies in the bull market that began in 2009. Since 2009 pullbacks in the order of 30% have been buying opportunities. The most recent pullback was slightly larger at 35%. The more people who are aware of this phenomenon the greater the potential it has to become a self-fulfilling prophecy.

The flip side of that argument is we know it cannot persist indefinitely because the bigger a share becomes the fewer people that are left who have to participate. That means the lows posted in December are a very important touchstone for the share and by extension the wider market.