Quantum theory gets physical.

[Jim__]

...

Giulio Chiribella, a theoretical physicist at the Perimeter Institute for Theoretical Physics in Ontario, Canada, and colleagues based their approach on a postulate called “purification.” A system with uncertain properties (a “mixed state”) is always part of a larger “pure state” that can, in principle, be completely known, the team proposes in the July Physical Review A.

Consider the pion. This particle, which has a spin of zero, can decay into two spinning photons. Each single photon is in a mixed state – it has an equal chance of spinning up or down. The pair of photons together, though, comprise a pure state in which they must always spin in opposite directions.

...

This purification principle requires the quantum phenomenon known as entanglement, which connects the parts to the whole. It also explains why quantum information can’t be copied without destroying it but can be “teleported” — replicated at a distant location after being destroyed at its point of origin.

Building on this principle, Chiribella and colleagues reproduced the mathematical structure of quantum mechanics with the aid of five additional axioms related to information processing. Their axioms include causality, the idea that a measurement now can’t be influenced by future measurements, and “ideal compression,” meaning that information can be encoded in a physical system and then decoded without error. . Other axioms involve the ability to distinguish states from each other and the ability of measurements to create pure states.

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[gateley]

1. I don't understand quantum mechanics at all, but somehow

I'm fascinated by it! So even though I'll read this going "huh?" I know I'll like it! Crazy, I know. Thanks for posting!! :hi:

[Eddie Haskell]

2. I got it ! Rumsfeld was a physics major.

"I don't know what the facts are but somebody's certainly going to sit down with him and find out what he knows that they may not know, and make sure he knows what they know that he may not know."



But seriously, I like the approach. Even though we can never predict the outcome, we can use it to determine useful information.

[damntexdem]

3. Well, it's only fair: after all, physical theory is quantum.

But there's a certain uncertainty about that, I guess. ;-)

[Permanut]

4. This applies only to the pion....

which is a completely different particle from the peon, the tampon, the coupon, the moron, the klingon, the clipon and the crouton.

[byronius]

5. Got me. But I have to kill you now. Sorry.

[Eddie Haskell]

6. Quantum Purification: the layman's definition

Shit happens but it follows rules such that, if you take and lump all the happening shit together, it’s the same old shit only cleaner.

[agent46]

7. So cool

But it doesn't mean what you think it means.

[struggle4progress]

8. From the paper: '... we provide a complete derivation of finite dimensional quantum theory based on

we provide a complete derivation of finite dimensional quantum theory based on purely operational principles. Our principles do not refer to abstract properties of the mathematical structures that we use to represent states, transformations, or measurements, but only to the way in which states, transformations, and measurements combine with each other. More specifically, our principles are of informational nature: they assert basic properties of information processing, such as the possibility or impossibility to carry out certain tasks by manipulating physical systems. In this approach the rules by which information can be processed determine the
physical theory, in accordance with Wheeler’s program “it from bit,” for which he argued that “all things physical are information-theoretic in origin” ...'