Theory vs. Computation

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Joined: Fri Jul 29, 2011 10:05 pm

Theory vs. Computation

Post by Minovsky » Tue Dec 13, 2011 5:24 pm

Two questions: one general, one specific.

General: What is the difference between 'Theoretical' and 'Computational' physics? I was under the impression that 'theoretical' meant 'computation' these days. Is there research which is theoretical, but not computational?

Specific: I'm filling out the application form for the PPPL NUF* program, and it asks me to declare a Research Project Preference: Experimental, Theoretical, or Computational. The theoretical research page on the PPPL website lists only simulation/modelling and computational research groups. I'm having a hard time distinguishing between what counts as 'theoretical' and what counts as 'computational'. Anyone at PPPL care to expound on this?

*Princeton Plasma Physics Laboratory, National Undergraduate Fellowship

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Joined: Tue Feb 07, 2012 12:18 am

Re: Theory vs. Computation

Post by alreadyconfused1 » Tue Feb 07, 2012 12:24 am

There is a difference between the two. However, many computation people also can do theory. The differences are:

1. Theorists spend time to develop a MODEL of what is going, whether it is semi-analytic, or semi-empirical, etc. That is their job, purely developing models, and also they can match models to experiments, etc.

2. Computational people tend to take really complicated models (such as the big bang, formation of the universe, etc to give a few) and figure out ways, using physics, math and computer tricks, to be able to simulate those models as best as possible, and then to try to match those to what is observed. They don't always make the theories, they are the ones who figure out how to make simulated data.

The difference is like the difference between the people who take experimental data, and those that design the apparatus. While the two may intersect, there are plenty of people who only design ways to TAKE the data, and there are plenty who only use those ways to actually TAKE the data.

So one of the best examples is computational cosmology. They have a good theory behind it. However, it takes lots of simulations, with the computational astrophysicists doing things like figuring out how to approximate real viscosity in a way that is both accurate, and fast. And then they take their huge simulations and ask "Do my simulations match theory, and do they match observation?"

So the two are different aspects of physics.

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