I see your point, the encryption only holds true if quantum mechanics is correct.

But could it have been hearts? No, it was actually a spades card the whole time, you just didn't know. It had the property of being a spades the entire time (a hidden variable). Could you spin flip his card to a hearts and have yours change to a spade faster than light? No. Quantum mechanics however works this way, although you still cannot transfer information faster than light, and there is no property (hidden variable) that tells you what it was before the measurement was made. Measuring the spin on a different axis will also give you non classical results in these entangled states.

Feynman's path integrals are over all space, or all paths, but are of the wave function. Bell's proof showed that any hidden variables would produce different results when measurements are taken, or Feynman's path integrals calculated. So no, hidden variables do not exist. Thinking about whether the particle is actually spin up or spin down before measurements are taken is meaningless, as quantum mechanics only give probabilities of the outcome of a measurement using the wave function to calculate these probabilities. It actually says nothing at all about the particle before measurements are taken.

That's what quantum encryption is used to exchange.

The whole basis of quantum encryption was mathematical and the error checking routines have been prove mathematically. It's only used to exchange keys.

Your idea supposes the card is actually a heart before you look at it and it couldn't be something else when you look at it. This supposes the particle is actually spin up or spin down before you make a measurement and that quantum mechanics must be missing this "hidden variable", i.e. it's not a complete theoretical description of reality. See Bell's Theorem for details as to why this is incorrect. There is no way to tell if it's spin up or spin down before you make the measurement and if there was a "hidden variable", quantum mechanics wouldn't work the way it does. You can also spin flip the particles several times before taking measurement without affecting the entanglement.

Quantum cryptography does error checking to assure no one else is measuring said quanta. Other measurements would introduce error if they don't commute with your measurements.

To prove Bell's Theorem you simply assume a single other hidden variable exists, perhaps signifying if the particle is actually spin up or spin down before you measure it. This assumption contradicts quantum mechanics and therefore cannot be true, so there is nothing else you can know about the system if quantum mechanics is the correct description.

If simply one more variable produced this result, I do not see how adding infinitely many more variables would help, or be of any practical use as a theory of nature.

Well you could still look at the underlying loans and see how they aren't triple A. They already gave crazy disclaimers about how dangerous it was to invest in them. The rating agencies are monopolies and blessed by the government, there's no free market in ratings agencies. A year ago S&P actually did something sensible and downgraded the US bond rating and immediately got investigated for fraud for rating those derivatives too high. But it's much worse now, all those people doing those crazy things got trillions in bailouts, and now the US government is guaranteeing an even larger percentage of mortgages.

See hotdog.

It would just take longer for markets to equlibrate. Less volume, more volatility. Higher transactions costs. I think of HFT as just how markets work. It should be less and less profitable as we move forward and algorithms and cpu cost goes down. Market makers giving certain companies HFT advantages to make massive profits and charge the buyer a higher price, are clearly monopolistic practices that go against everything HFT is designed to do.

HFT means high-frequency, not long term. Bubbles take years to develop, no microseconds.

I think it had more to do with the government guaranteeing normal loans (subsidized by low FED interest rates), government subsidized loans and government entities buying sub-prime loans. If you were a bank, why wouldn't you make bad loans to sell to Franny and Freddy.

However, it's rather odd that the Obama campaign would release this. Perhaps they are proud of their lack of privacy record.

Since when did you have only 1 pi radians in a circle? I think you're using madeup units.