Unitary Evolution in Tight Shorts

i-285024f92a693cec28e289b3a84b0fab-lara croft_qjpreviewth.jpgTerence Tao explains quantum theory as a game of Tomb Raider:

Imagine first that Lara is about to navigate a tricky rolling boulder puzzle, when she hears a distant rumbling sound - the sound of her player saving her game to disk. From the perspective of the player, what happens next is the following: Lara navigates the boulder puzzle but fails, being killed in the process; then the player restores the game from the save point and then Lara successfully makes it through the boulder puzzle.

Now, how does the situation look from Lara's point of view? At the save point, Lara's reality diverges into a superposition of two non-interacting paths, one in which she dies in the boulder puzzle, and one in which she lives. (Yes, just like that cat.) Her future becomes indeterministic. If she had consulted with an infinitely prescient oracle before reaching the save point as to whether she would survive the boulder puzzle, the only truthful answer this oracle could give is "50% yes, and 50% no".

It gets weirder from there, but it's a fun read. And since everybody else in the physics blog world has linked to it before me, I'll throw in a gratuitous image.

Tags

More like this

Part two of three of an explanation of "quantum teleportation" experiments, from July of 2002. This one goes through the basics how teleportation works. I might be able to do better now, having worked through it in more detail in order to teach about it in my Quantum Optics class, but it's been a…
A continuation of the lecture transcription/ working out of idea for Boskone that I started in the previous post. There's a greater chance that I say something stupid about quantum measurement in this part, but you'll have to look below the fold to find out... At the end of the previous post, I…
I seem to have been sucked into a universe in which I'm talking about the Many-Worlds Interpretation all the time, and Neil B keeps dropping subtle hints, so let me return to the whole question of decoherence and Many-Worlds. The following explanation is a recap of the argument of Chapter 4 of the…
The New York Times offers an article profiling Terence Tao, mostly focussing on his child prodigy background: Dr. Tao has drawn attention and curiosity throughout his life for his prodigious abilities. By age 2, he had learned to read. At 9, he attended college math classes. At 20, he finished his…