Enredo Quántico

Quantum Entanglement

Este va en inglés porque el diálogo original está en ese idioma y si se traduce pierde un poco de encanto.Y además porque toda la información que le sigue también está en ingles y es demasiada como para traducirla, a menos que los miles de visitantes se pronuncien a favor de la traducción...que por el momento no creo que suceda, porque el unico visitante soy yo.

- Larry: Don, Are u familiar with the term "Quantum Entanglement"?.

- Don: I dont think so..

- Larry: Well, is a theory that holds that photons come in pairs, which are separated by space-time, but they are always in instantaneous,inexplicably communication with each other. Einstein called it "spooky action at a distance". You know, I find that notion farly romantic.

- Don: How's so?

- Larry: Well, we affect each other , even when we don’t have the intention to do that. Even when we don’t want to do that, we are still connected. Can u see? Even when we try to be unaffected.

- Don: Why I get the feeling that you are talking about my love life?

- Larry: Don, The universe is accelerating at such a rate, that someday eventually everything will fly apart, and all matter will just drift alone and will become disconnected. How sad would be if human beans would behave in a similar fashion. And after a considerable inner debate, I find that the risks of human contact are more than compensated for by the rewards.

Theory:

Quantum theory has serious conceptual problems, which one can choose to tackle using the concept of information. An example is the effect called 'entanglement'. Two systems are said to be entangled if they are correlated in a stronger way than is possible in classical physics models. The existence of such correlations raises questions as to whether the world is 'real' and/or 'non-local'. Beyond that entanglement is now also viewed as a resource and studied as such using information theoretical concepts.
(cuote from here)

There is a popular example that shows this concetps, called
Schrödinger's conjecture" :

One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts.

When does a quantum system stop existing as a mixture of states and become one or the other?

If the cat survives, it remembers only being alive. Our intuition says that no observer can be in a mixture of states, yet it seems only cats can be such a mixture. Are cats required to be observers, or does their existence in a single well-defined classical state require another external observer?

In the many-worlds interpretation of quantum mechanics, which does not single out observation as a special process, both alive and dead states of the cat persist, but are decoherent from each other. In other words, when the box is opened, that part of the universe containing the observer and cat is split into two separate universes, one containing an observer looking at a box with a dead cat, one containing an observer looking at a box with a live cat.

Since the dead and alive states are decoherent, there is no effective communication or interaction between them. When an observer opens the box, they become entangled with the cat, so observer-states corresponding to the cat being alive and dead are formed, and each can have no interaction with the other. The same mechanism of quantum decoherence is also important for the interpretation in terms of Consistent Histories. Only the "dead cat" or "alive cat" can be a part of a consistent history in this interpretation.