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Science Section => Science General Discussion => Topic started by: Solitary on July 03, 2013, 09:20:14 AM

Title: Quantum mechanics
Post by: Solitary on July 03, 2013, 09:20:14 AM
:evil:
Title: Re: Quantum mechanics
Post by: Voskhod on July 04, 2013, 07:17:51 PM
Honestly, as far as I can tell Quantum mechanics does rely on consciousness to operate (or, more specifically, observation - Schrodinger's cat and all that jazz). This is why Quantum mechanics terrifies me utterly and why I refuse to research it on a technical level.
Title: Re: Quantum mechanics
Post by: Solitary on July 04, 2013, 07:38:41 PM
:evil:
Title: Re: Quantum mechanics
Post by: Voskhod on July 04, 2013, 07:50:02 PM
I'd heard a few hints of that but merely dismissed them as rumors. Other than that, I have read a handful of a few physics papers that essentially came to the conclusion that quantum particles do change their behavior when observed. The one I remember most fondly was that of a physics experiment somewhere that measured and realized that the half-lives of radioactive and unstable isotopes were actually extended considerably when scientists observed them for prolonged periods of time them under electron microscopes.
Title: Re: Quantum mechanics
Post by: GurrenLagann on July 04, 2013, 11:51:22 PM
As far as I know (which is admittedly very little) QM does not require a conscious observer for the collapse of the wave function. Joesephazaloo would be the guy here to ask though.
Title: Re: Quantum mechanics
Post by: Solitary on July 05, 2013, 12:16:02 AM
:evil:
Title: Re: Quantum mechanics
Post by: Colanth on July 05, 2013, 12:29:20 AM
Electron microscope, Solitary.  It's the beam of electrons that causes the change.  If we could observe them with "ambient electrons" or some such, we'd probably see no change due to observation.

Heisenberg doesn't say that measuring one quantity changes others, he says that we can't know, say the velocity and location of an electron at the same time, because the more accurately we measure the velocity, the less accurate is the measure of its location (due simply to the nature of measurement).
Title: Re: Quantum mechanics
Post by: Plu on July 05, 2013, 02:33:32 AM
Imagine being in a completely dark room trying to find a rolling ball. And the only way you can find the ball is by throwing smaller balls and waiting for the impact sound to measure how far away it is. You can't observe the ball without changing its position slightly from the impact, and the more balls you throw to pinpoints its location, the more the ball will be rolling around, making it harder to detect how fast it is moving (because you keep changing its motion). But if you try to detect its speed over time, you can only throw a few timed balls. That'll get you a good idea of how fast it's moving around, but it'll be a lot harder to pinpoint its exact location because you have less measurements.

The "change from observation" doesn't require a conscious ball-thrower, if we use a robot to measure it it'll still change the outcome. It's just that in the natural world there aren't really any things that we'd notice impacting these particles, which makes some people think that you need a consciousness to observe them. But that's not really how it is. It's just that we can only observe them by physically interacting with them, and that's changing them.
Title: Re: Quantum mechanics
Post by: Solitary on July 05, 2013, 08:32:23 AM
:evil:
Title: Re: Quantum mechanics
Post by: Solitary on July 05, 2013, 08:35:36 AM
:evil:
Title: Re: Quantum mechanics
Post by: Colanth on July 05, 2013, 04:57:53 PM
Quote from: "Solitary"
Quote from: "Colanth"Heisenberg doesn't say that measuring one quantity changes others, he says that we can't know, say the velocity and location of an electron at the same time, because the more accurately we measure the velocity, the less accurate is the measure of its location (due simply to the nature of measurement).

You are correct! Thanks! I was just trying to make a point that it isn't just looking that changes the outcome.
Not due to Heisenberg.  Due to Schrödinger, looking not only changes the outcome, looking determines the outcome.  (Schrödinger says that there's no outcome until you look.  The cat is neither dead nor alive until you open the box.  Or course it has to be a quantum cat, not a biological one.)

It's like Smith deciding to make a ball out of wood, not plastic, and Jones deciding to spray it white, not black.  It's not black due to Smith, but it is due to Jones.