I’m a big fan of distributed systems – complex networks of an extremely large number of independent entities governed by simple and transparent rules. Not surprising, really, that I work professionally on next-generation products and services based on the Internet, one of the most successful man-made distributed systems in existence.
As a result, it’s not surprising that I found this article in the latest issue of Scientific American compelling:
Scientific American: Using Causality to Solve the Puzzle of Quantum Spacetime
A new approach to the decades-old problem of quantum gravity goes back to basics and shows how the building blocks of space and time pull themselves together
By Jerzy Jurkiewicz, Renate Loll and Jan Ambjorn
Here is a quick synopsis:
- Quantum theory and Einstein’s general theory of relativity are famously at loggerheads. Physicists have long tried to reconcile them in a theory of quantum gravity—with only limited success.
- A new approach introduces no exotic components but rather provides a novel way to apply existing laws to individual motes of spacetime. The motes fall into place of their own accord, like molecules in a crystal.
- This approach shows how four-dimensional spacetime as we know it can emerge dynamically from more basic ingredients. It also suggests that spacetime shades from a smooth arena to a funky fractal on small scales.
I’ve been following modern cosmology theory fairly closely for the past 15 years, and I found this approach compelling and refreshing in a number of ways. It may not be an effective path towards resolving theories around quantum gravity, but there are clear reasons to give it due consideration:
- The modeling techniques will be extremely familiar to anyone with an advanced background in modern computer graphics approaches and theory.
- The idea that a few simple assumptions will self-aggregate into the universe that we see around us avoids the never-satisfying anthropic principle fallback. (The anthropic principle is effectively a circular argument that says, “Well, the universe is this way because if it wasn’t this way, we wouldn’t be here to ask the question.” It’s about as intellectually satisfying as the movie 10,000 BC.
- The simplicity of the model scores favorably with Occam’s Razor vs. other competing theories of quantum gravity and string theory.
- The model is based on the insight that causality (related to the 2nd law of thermodynamics) is a fundamental principle of our universe.
That last bullet was particularly compelling for me, since the idea that time is a dimension with equal fluidity to the spacial dimensions has always conflicted philisophically with the concept that entropy must always increase. It’s the reason why almost every form of time travel breaks the accounting for mass/energy.
Anyway, read it and let me know what you think. I had someone at work tease me just last month about reading Scientific American, comparing it to Popular Science. Personally, I find that articles like this continue to justify my subscription dollars.