I have mentioned my friend and colleague Fred Kappetijn before. We regularly look at bigger issues and one of these has been the role of information in our universe. This might be an article you might want to ponder about over the Christmas break

This is not your usual way of discussing information. This goes way beyond how we look at information in the context of Information and Communications Technology. Here we are talking about nothing less than entangled quantum information as a possible explanation for gravitation being an emergent force (quantum gravity) and not a fundamental force of nature like the electromagnetic force.

It is even a candidate to revisit the Standard Theory of Cosmology that states that the universe was created in the “Big Bang” from pure energy and is now composed of about 5% ordinary matter, 27% dark matter and 68% dark energy. Is “dark matter” perhaps “information”, or has information something to do with it? Is information perhaps also at the core of quantum mechanism? The relation between dark energy and quantum gravity is so far unclear.

The big question then, of course, is what in this context is information? Sorry I can’t give you that answer (yet), but it is interesting to investigate where this field of theoretic research sits now.

For some times there have been on and off discussions about quantum information as a natural element in the universe. American theoretical physicist John Archibald Wheeler already in the 1990s started this discussion.

Quantum is defined as the smallest quantity of a physical element like energy, light (photon), mass and probably even space and time on the smallest scale possible — the Planck scale (10⁻³⁵ m). At that level, quantum doesn’t follow traditional physics anymore. It becomes a wave like phenomenon, with very strange attributes such as entanglements.

As a matter of fact, we still have no idea how quantum mechanics works, but we can and do apply quantum mechanics on a large scale offering all the modern electronic goodies varying from smart phones to GPS services.

Interestingly, while we have no explanations at this micro level, we have a similar problem at the macro level. We still don’t know what 95% of our universe is made of. To cover up our ignorance, we call this unknown “dark matter” and “dark energy”. It is thought that dark matter is the extra mass that adds to gravity to keep the universe intact and dark energy to explain the accelerated expansion of the universe.

Perhaps we are betting on the wrong horse here and is gravity not a fundamental force of nature? Perhaps it is an emergent force caused by yet another more unifying force. If this would be proven to be right, that will require a radical rethink of physics as we know it. Dutch theoretical physicist and string theorist Erik Verlinde theorised that gravity instead is a consequence of the universe striving to maximise entropy.

Let’s park this for the moment.

In the 19th Century, the measurement of energy that develops from disorder was established as being entropy. Thermodynamic entropy describes the state from order to disorder as we see it all around us — we are born, we grow, get old and die. A bushfire reduces a forest to heat, smoke and ash. However, as energy remains stable in a closed system – thermodynamic equilibrium – it is possible to measure entropy.

Entropy is a measure for the number of possible states of several particles in a closed space.

Interestingly, entropy was also discovered in information technology. Mathematicians Claude Elwood Shannon and John von Neumann were the first to study this in telecommunications, where it was noticed that some information was lost between sending and receiving.

Entropy here is the measure of the amount of missing information before reception. The higher the entropy, the more information is lost. The information industry has been the major beneficiary of this discovery and has significantly contributed to the enormous development of this sector.

Thermodynamic entropy follows a similar pattern as informational entropy. In both situations, it is about what happens with the information content. The two types are fully complementary and are descriptions of the same phenomenon of nature, which is that all processes tend to chaos, decreasing the information content.

We can see this with the enormous amount of data that we need to address the increasingly more complex conditions in our society. An enormous amount of energy is needed in data centres to create, crunch and analyse data. Equally there is a significant amount of energy released in that process. This clearly points to a process of entropy.

Theoretical physicist Jacob Bekenstein developed the “Bekenstein bound”. This puts a boundary to the maximum amount of information that can potentially be stored in each finite region of space and this has a finite amount of entropy.

This led some physicists to start thinking about the possibility that information could be a natural phenomenon. It might be a missing element that perhaps can be further linked to quantum mechanism (entanglements) as well as to the missing 95% in our universe.

Is that entanglement with vibrating strings triggered by information? The string theory is an attempt to describe all physical phenome in one single coherent mathematical model. Could there be in string theory an assumption of the possibility of coupling of entanglement triggered by information?

Indeed, John Wheeler seems to suggest it is. He went as far as to say that information is fundamental to the physics of the universe. According to his “it from bit” concept, all things physical are information-theoretic in origin.

The mathematician John von Neumann suggested to not call this “information” but “uncertainty”. Information has so many possible definitions that it will only be more confusing.

Erik Verlinde further theorised that gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings. He introduced the theory of entropic gravity which he derived by using parts of the string theory.

According to this theory, rather than particles displaying a point-like behaviour, they follow a string-like behaviour. This provides for a different approach on how particles propagate through space.

Like quantum, entropy, strings and dark matter, now also information will require a lot more explanation to understand what this is. So, it looks like this is all even more complex than we thought it was, but information might be the key to better understand both quantum mechanics and our universe. That is a fascinating thought.

Best wishes for the festive season.

Paul Budde