Gravity from first principles, no longer a fundamental force?

Erik Verlinde, a very well respected physicist, has posted a paper that argues that Gravity is not really a fundamental force of physics. Rather he believes it arises from a tendency of matter to seek to increase its’ entropy. (Or at least as far as I understand the paper so far.)

The basic idea is to consider reality in terms of information theory – the more information concentrated in a region, the powerful the attraction to a region of less information. (At least in terms of holographic view of the Universe ala String theory.)

And since information is related to energy then it is also related to temperature. Which means that if information is related to gravity, gravity is connected to temperature, and we’re in the realm of thermodynamics and information flow.

From the blog of the Hammock Physicist:

“Subsequently, Verlinde takes a deep dive: if an acceleration is proportional to a temperature, it has all the characteristics of an entropic effect. Entropic acceleration results from the tendency of a system to evolve such that there is an increase in the minimum number of bits required to describe the system in all its details. Could it be that gravitational attraction results from nothing more than a growth in number of bits required? Verlinde argues that such is indeed the case. Key is that one needs to follow a holographic approach with all bits describing reality residing at holographic screens.

I think the relation to entropic effects is clearest in one of the Newtonian scenarios Verlinde considers: a given matter distribution that creates a gravitational potential. Verlinde requires the holographic screens to coincide with equipotential surfaces, and arrives at the conclusion that the bit saturation (the number of bits required to describe the system divided by the number of bits available on the screen) equals -phi/2c^2 where phi represents the Newtonian gravitational potential. This bit saturation is a positive number that vanishes at large distances. If one shrinks the holographic screen whilst ensuring it keeps following the equipotential surfaces, the bit saturation keeps growing until it reaches a value of unity at which the screen is saturated with information. It can not shrink further, a black hole hole has formed with the screen representing its holographic horizon.

Again, you have to reverse this thinking. When doing so, the picture that emerges is that of a gravitational attraction (acceleration defined by a gravitational potential) that results from a tendency of physical systems to evolve such that the holographically available bits saturate with information. This tendency towards bit saturation is an entropic effect, that we experience as gravitational attraction.”

Read the full article here.

From this point Verlinde shows that it’s possible to derive the Equivalence Principle, and thus Einstein’s field equations and Newton’s laws.

Which is huge. To be able to explain the Equivalence principle without recourse to something like the Higgs particle is a very very big deal. It would resolve one of the fundamental questions of modern physics.

Wow.

Now we just need to find a way to test this… though I suppose if the LHC actually finds the Higgs, then there’s likely not a whole lot here.

Author: Nick Knisely

Episcopal bishop, dad, astronomer, erstwhile dancer...

3 thoughts on “Gravity from first principles, no longer a fundamental force?”

  1. The Higgs mechanism allows particles to acquire mass dynamically. I don’t think it has much bearing on this interpretation of mass; the equivalence principle applies to any mass, intrinsic or dynamically acquired.

  2. Douglas – my memory is that the Higgs mechanism is supposedly the connection between inertial and gravitational mass. But I might well have that wrong, I was never a particle physicist, though I’ve seen others making the same suggestion in other places.

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