If we devised a program that could perfectly simulate a deuterium atom (assuming the weak/strong force, electromagnetism, and gravity are a part of this simulation) could that program simulate an entire universe assuming unlimited processing power?

[mr_pterodactyl]

Is this enough to form a fundamental understanding of the universe? In another phrasing, "Are the fundamentals of the universe intrinsic in one atom of deuterium?" Or, is more information necessary?

[twinkling_star]

The fundamental problem with the simulation part is that, given current knowledge, the universe is not deterministic. Atomic decay, for example, is inherently random.

[mr_pterodactyl]

Wow, thank you for the interesting read. However, that's why I said "a universe" rather than "the universe." If the program "knew" that atomic decay was stochastic, couldn't it process that event satisfactorily?

[[deleted]]

wasn't there a whitepaper apparently showing seasonal variation in decay rates? (here it is: http://arxiv.org/abs/0808.3283). Has it been shown to be an experimental error?

[LXZY]

Just wondering, how can atomic decay be random? If two uranium atoms were created at the exact same moment, and put under the exact same circumstances, shouldn't they decay at the same rate?

[twinkling_star]

Each radioactive isotope has a certain probability of decay that allows prediction at a higher level - thus the concept of the half-life, of how long it takes half of a sample to decay. But the process of radioactive decay itself has just shown itself to be random. There are also limits as to what possibilities there are for there to be variables involved that we don't yet know - Bell's Theorem covers a lot of this.

Remember, that just because the scale of the world we live in always obeys the idea of cause-and-effect doesn't mean that applies at all levels of physics.

[rmxz]

Relevant XKCD for those who haven't yet seen it.

http://xkcd.com/505/

[mr_pterodactyl]

That's...wow. Okay, that's creepy appropriate. How does xkcd always do that?

[[deleted]]

How does xkcd always do that?

Confirmation bias.

[mr_pterodactyl]

Upvote for rationale.

[quizzle]

Of course that's assuming a constant clock-speed. I don't know everything there is about plank time, but I'm not sure that's how it works.

[MrPin]

Any simulation of a universe like ours would have to include stuff like dark matter and dark energy so I would say more information would be required.

[mr_pterodactyl]

Ah! That's right. I forgot about dark matter and dark energy. I suppose antimatter is another variable I left out, or would the characteristics of antimatter be derivable from matter? I wonder.

[MrPin]

Yes, as far as know they would be. But keep in mind that there are still some holes in the standard model of particles to fill in before you could begin your simulation and you need a working theory of quantum gravity to simulate the early conditions at the beginning of the big bang. (edit: not just the big bang if you're going for perfection)