-- Mike Stay Cryptographer / Programmer AccessData Corp. mailto:[EMAIL PROTECTED]
Dear Mike, I think you've overestimated the implications of this method for code breaking. My previous work with Dan Abrams did indeed show that nonlinear quantum mechanics could be used to solve NP and #P oracle problems (which in my opinion should be regarded as evidence against nonlinear quantum mechanics). The idea is to use the nonlinearity to amplify small differences in the wave function. The feedback method described in the current paper could also be used to amplify small differences: accordingly, you could use it to solve hard problems by the same method. The catch is that order to amplify differences of the size 1/N, you need N copies of the same system. So to solve exponentially hard problems by this feedback method, you need exponentially many copies (we're up front about this in the paper). Cryptography remains as safe as it was before. Which is a lucky thing, since I'm about to use the web to buy some plane tickets. Yours, Seth
