This strikes me as rather uninformed. Physics is far from a completely undiscovered realm. The standard model of particle physics (completed by the mid-70s) + general relativity (ca 1915) fits every experiment ever performed. Unexplained astronomical observations can be accommodated by additions which, while phenomenologically important, add nothing conceptually new. The remaining Holy Grail, quantum gravity, suffers no lack of proposed solutions; what it really does suffer from is a lack of ways to test any of them.

The sad reality of "fundamental" physics is, and has been for decades, that there is really very little that is both doable and worth doing. If somebody were to dump a Genius grant on me today, with the only condition being "work on whatever you want in physics for the next 5 years"... I would feel compelled to give it back. Because I really don't see anything sufficiently promising or interesting in physics that I would be willing to dedicate the next 5 years to it. (All those people you see screaming for more physics funding? What they are really screaming for is their "right" to keep comfortable upper middle class lifestyles, funded by the tax payers, in exchange for nothing of any value.)

Now compare that to what is going on in software. If "new login scripts" is the most interesting thing you can think of, you really need to broaden your horizons. Just look at the last few years of very rapid progress in deep learning. There is nothing comparable going on in physics. Things like thought vectors are giving me vertigo - my old skepticism about the feasibility of general AI has been seriously dented lately. Problems which once looked completely intractable suddenly look easy, and you start wondering how many more surprises are just around the corner, and how many - or rather few - years it might really take to get there.

And the potential? Suppose you managed to write down the ultimate, complete, fully quantized, elegantly unified, simple, concise, true Theory of Everything. There it is, an exquisite formula on a sheet of paper. It summarizes everything we know about physics. Everything around us follows from it. Wonderful. But... what do you do with it? Sure, stare at it, marvel at its ingenuity and the centuries of concerted effort needed to get there... but then what? How long can you stare at a sheet of paper and marvel at the history and elegance of an equation before it gets a little... old?

Now compare what AI, even just the narrow kinds emerging right now, can do, and the potential of true general AI. Now that would - will - obviously change the world.

And you think deep learning isn't physics? How much RG did you study in grad school?

More importantly, many "fundamental" questions about mathematical physics will soon get to be resolved through tabletop type experiments. AdS/CFT type methods led to the first analytical proof of Bethe ansatz results I've ever seen that made me sit up and take notice of that field (BA, not AdS/CFT).

It disappoints me that on pressing issues of our time like climate change, APS can't seem to get its shit together and take a stand. This may be a symptom of what you are saying, the best and the brightest are going to the fields you describe and taking the power and the klieg lights with them.

PS: And where the dickens do you think belief propagation came from - I certainly first heard about it from statistical physicists. To treat deep learning in a divorced manner as you are is like saying oh, I'm too lazy to learn how the foundations of my house are mortared, I just want to rearrange the furniture in the solarium.

To establish in a semi-rigorous way the (btw obvious) relationship between coarsening in physics and in stacked neural networks, as was done long after the latter became a thing [1][2], is at the same level as observing the analogy between Black-Scholes and diffusion. It's cute, but it does not turn the subject into physics.

It should go without saying that you can not, by definition, resolve fundamental questions about mathematical physics by experiment.

The APS took a stand on climate change years ago [3]. It was clear enough to make Harold Lewis [4] and Ivar Glaever [5] resign in protest.

P.S. Belief propagation was first proposed by Judea Pearl in 1982 [6]. The closest connection to physics one could realistically claim is that Pearl got a M.Sc. in physics before turning (back) to electrical engineering and then AI.

[1] http://arxiv.org/abs/1301.3124

[2] http://arxiv.org/abs/1410.3831

[3] http://www.aps.org/policy/statements/climate/

[4] http://dotearth.blogs.nytimes.com/2010/10/15/a-physicists-cl...

[5] http://www.telegraph.co.uk/news/earth/environment/climatecha...

[6] https://www.aaai.org/Papers/AAAI/1982/AAAI82-032.pdf

Some good points, but you refused to address my Bethe Ansatz comment (cf. http://arxiv.org/abs/1208.5055, https://en.wikipedia.org/wiki/K-theory_(physics)#Reconciling...)

and in any case, I recall Schwinger resigning from the APS over cold fusion. Doesn't make cold fusion right.

Also I didn't realize the ground state of the Hubbard model wasn't mathematical physics? Spin liquids aren't mathematical physics? This is the same old story where people like des Cloizeaux and Pearson discovered bosonization and helped establish the long tradition of condensed matter people studying the Heisenberg model and making useful contributions to "high energy" physics and basically get ignored

In the end my point is that you loved the idea of changing the world more than you loved physics. There's nothing wrong with that.

Physics major here building login validation as you do. I have to say I miss Phys but there is no way for me to going back. Once your living standard is high. You can't afford to lose it for a phD student allowance. My dream now is just to make a lot of money in this tech bubble and educate my kids to be incredible scientists without worrying about money. As for me, I will just try to forget about it.

Don't say there is nothing to be discovered in physics, please you are just making yourself less academic intelligent as you might have sound.