Dr. Gates, a distinguished theoretical physicist (with a truly inspiring biography), recently made an astounding statement during an interview on NPR (the clip from the On Being show can be found here – a transcript is also online).  It gave the listener the distinct impression that he uncovered empirical evidence in his work that we live in a simulated reality.  In his own words:

(…) I remember watching the movies, The Matrix. And so, the thought occurred to me, suppose there were physicists in this movie. How would they figure out that they lived in the matrix? One way they might do that is to look for evidence of codes in the laws of their physics. But, you see, that’s what had happened to me already.

I, and my colleagues indeed, we had found the presence of codes in the equations of physics. Not that we’re trying to compute something. It’s a little bit like doing biology where, if you studied an animal, you’d eventually run into DNA, and that’s essentially what happened to us. These codes that we found, they’re like the DNA that sits inside of the equations that we study.

Of course Dr. Gates made additional qualifying statements that cautioned against reading too much into this, but media, even the more even-handed NPR, feeds off sensationalism. And so they of course had to end the segment with a short excerpt from the Matrix to drive this home.  It would be interesting to know how many physicists were subsequently badgered by family and friends to explain if we really live in the Matrix. So here’s how I tackled this reality distortion for my non-physicist mother-in-law:

• Dr. Gates has been a pioneer in Supersymmetry research (affectionately abbreviated SUSY) but just as with String theory there is an absolute dearth of experimental verification (absolute dearth meaning not a single one).  While SUSY proved to be of almost intoxicating mathematical beauty the recent results from LHC have been especially brutal. Obviously, if nature doesn’t play by SUSY’s rules it will be of no physical consequence if Dr. Gates finds block codes in these equations (although it certainly is still mathematically intriguing).
• The codes uncovered in the SUSY equations are classic error correction bit codes. The bit, being the smallest informational unit, hints at a Matrix style reality simulated on a massive Turing complete machine.  There are certainly other smart people who actually believe in such (or a very similar) scenario – e.g. Stephen Wolfram advocated something along these lines in his controversial book.  The one massive problem with such a world view is that we rather conclusively know that classic computers are no good at simulating quantum mechanical systems, and that quantum computers can outperform classical Turing machines (the same holds in the world of cellular automatons, where it can be shown that quantum cellular automatons can emulate their Turing equivalent and vice versa).

If Dr. Gates had discovered qbits and a quantum error correction code hidden in SUSY, that would have been significantly more convincing.  I could entertain the idea of a Matrix world simulated on a quantum computer.

At any rate, his equations didn’t provide a better answer to the question of why anyone would go to the trouble of running a simulation like the Matrix.  In the movie, the explanation is that human bodies perform as an energy source just like a battery.  Always thought this explanation fell rather flat.  If a mammalian body was all it took, why not use cows, for example?  That should make for a significantly easier world simulation – an endless field of green should suffice. Probably wouldn’t even require a quantum computer to simulate a happy cow world.