# Is Quantum Mechanics An Island in Theoryspace?

- Publication Year:
- 2004

## Explore PlumX Metrics

What are PlumX Metrics? How can they help tell the story about this research? How can I use them?

Learn more- Repository URL:
- http://philsci-archive.pitt.edu/id/eprint/1858

- Author(s):

##### preprint description

This paper investigates what happens if we change quantum mechanics in several ways. The main results are as follows. First, if we replace the 2-norm by some other p-norm, then there are no nontrivial norm-preserving linear maps. Second, if we relax the demand that norm be preserved, we end up with a theory that allows rapid solution of hard computational problems known as PP-complete problems (as well as superluminal signalling). And third, if we restrict amplitudes to be real, we run into a difficulty much simpler than the usual one based on parameter-counting of mixed states.