What Time Is Now?
A possible tip of the TOE (as in Theory Of Everything)
Once you embark on a journey of self discovery, sooner or later it will dawn upon you that consciousness is identical “in” all living beings, and that time and space are illusions. You will realize that there is only here and now.
How delighted I was, when, a several days ago, I found the work of Julian Barbour, PhD, a British theoretical physicist, author, and visiting professor at the University of Oxford.
According to Wikipedia, shape dynamics (SD), as Barbour calls his theory, is “a theory of gravity that implements Mach’s principle, developed with the specific goal to obviate the problem of time and thereby open a new path toward the resolution of incompatibilities between general relativity (GR) and quantum mechanics (QM).”
Let’s start with the crucial fact that time in Barbour’s theory is emergent. Reality is a series of “nows”, or snapshots of states of the whole universe which are composed into fluid motion by our brains. Thus, time is just an illusion, a useful concept for measuring the rate of change, derived from our capability to remember previous states — exactly as it can be observed.
But Barbour goes even further. He claims that space is emergent too, i.e. length is not primary as it is dependent on relative relationships between objects, or in other words and more precisely, “all measurements of length are local comparisons,”¹ which again is something that can be observed.
One could say that Barbour’s theory is relative in true Machian sense, because while Newton had absolute space and time, Mach-inspired Einstein, even though he departed from Newton’s notion of fixed spacial grid, still retained an absolute 4D space-time as a reference frame (“block universe”).
And therein lies the problem — because QM uses rigid clock, and time in GR is more arbitrary, scientists struggle for more than 80 years to quantize the gravity in order to arrive at TOE (or Theory Of Everything).
Of course, at this point one could argue — why push for SD? Why not go with string theory (ST) or loop quantum gravity (LQG), the two leading candidates for TOE, in the first place?
For starters, as Natalie Wolchover writes in her article, “physicists have found no particles that could comprise dark matter, no siblings or cousins of the Higgs boson, no sign of extra dimensions, no leptoquarks — and above all, none of the desperately sought supersymmetry particles that would round out equations and satisfy ‘naturalness,’ a deep principle about how the laws of nature ought to work.” There are also other, rather pragmatic and mundane problems that plague ST, e.g. its background dependence and vacuoseness, or black holes popping up everywhere in certain scenarios, etc. All in all, ST is currently more a “theory of anything” than TOE, which, at least for now, rules it out as a suitable candidate.
Secondly, Barbour is allegedly the “grandfather” of LQG, so, go figure (then again, I didn’t find any other reference of this fact except a brief mention in a talk of one of Barbour’s collaborators¹).
However, the most important and compelling reason is that only SD, at least to my knowledge, managed to remove time from the equation.
In 2010, Henrique Gomes, Sean Gryb, and Tim Koslowski published their paper², where they expanded on Barbour’s work, and described gravity in a fully relational, locally scale invariant manner, successfully implementing Mach’s principle.
In lay terms — they created a theory that is, on a local scale, equivalent to classical GR, but does not fall apart at singularities³, and it does this without any crude hacks or gazillion dimensions unlike all the other theories. On top of it, they’ve done it without any need for time (i.e. “external clock”).
Truly, less is more.
It’s also worth a mention that Hans Westman from Spanish National Research Council, Department of Particles, Fields and Cosmology thinks that abolishing a scale of measurement and making everything completely relative might explain away the need for dark matter, while David Wiltshire, a theoretical physicist at the University of Canterbury in New Zealand, adds that dark energy is an illusion, too, and relational approach could explain the appearance of an accelerated expansion of the universe without it⁴.
And finally, the cherry on the cake — in 2017 a team of scientists managed to send 2 qubits “back in time”⁵, essentially reversing entropy. So, there goes the arrow of time (hm, but where exactly?).
Well, but to be completely honest, whether it’s all really the tip of the TOE, only time will tell :D
I also highly recommend that you watch the talks by the men themselves. It’s not that hard to understand, and it’s really something.
Julian Barbour, Timeless Explanation: A New Kind of Causality
Sean Gryb, Barbour’s Shape Space as an Ontology for Gravity
Tim A. Koslowski, Shape Dynamics
Henrique Gomes, Shape dynamics: a relational view of the Universe
References
¹ Sean Gryb in the talk above.
² Gomes, H., Gryb, S., Koslowski, T. 2010. Einstein gravity as a 3D conformally invariant theory. Retrieved from https://arxiv.org/abs/1010.2481
³ Mercati, F. 2014. “13 Solutions of Shape Dynamics”, A Shape Dynamics Tutorial. (pp. 67–113). Retrieved from https://arxiv.org/abs/1409.0105
⁴ Zeeya Merali in http://discovermagazine.com/2012/mar/09-is-einsteins-greatest-work-wrong-didnt-go-far (pp. 3)
⁵ G. B. Lesovik, I. A. Sadovskyy, M. V. Suslov, A. V. Lebedev, V. M. Vinokur. Arrow of time and its reversal on IBM quantum computer. 2017. Retrieved from https://arxiv.org/abs/1712.10057