Posts tagged particle.

RE: Observation & The Double-Slit ›

RE:

If we must disturb a particle to observe what it did, and the author claims that the experiment was designed so that the particle would not be disturbed until after it “decided” to act as wave or particle… how do we know that it decided to be a [particle] at all? 

I’d love a better explanation of Wheeler’s variation on the double-slit…

- Olena

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Camerxn has a pretty good { response } with lots of useful links.

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As for the first part of my question: it was not about whether the observed “object” is a particle or wave — it’s both. That much is made clear in theories about { wave-particle duality }.

Light is made of elementary particles called photons, but those photons don’t have well-defined trajectories. At any given time, their positions are diffused clouds of probability that move like waves. Thus, light can act like a wave, going around obstacles and creating patterns of interference. Or a photon can act like a particle, producing a discrete click when it hits a detector. The behavior depends on the experimental measurement.

- Science News

The question is about what we detect it to be, and how — if we don’t interfere with it — we can know whether it showed up as a particle or wave prior to when we do finally interfere with it. A wave/particle is always a wave/particle until it’s prompted (by an interaction) to make a choice between the two. So unless I misunderstood the premise of Wheeler’s experiment (also a question — did I?) how can it “decide” prior to when we force it do “decide”?

Also, especially looking back on the aforementioned { Science News article } about Wheeler’s experiment, I think we need to find a new way to talk about particles, or QM, or physics in general. It is not helpful to the layman to describe these events as if we’re dealing with “objects” that have “consciousness” — it creates confusion and misunderstanding, and allows people who like to jump to conclusions to attribute magical qualities to the science.

Part of the reason I’d like to understand these problems better is to be able to communicate them in a more comprehensible way that doesn’t make use of awful, misleading metaphors for what’s really going on.

Art by { dvdp }

THE PHYSICS OF SPIRALS?

Perhaps someone with more experience in math & physics can give some insight about this:

I’ve subscribed to a weekly newsletter from { Kurzweil AI } (Many of you might find it interesting; it covers futurism, technology, science, etc.) Recently, there were two consecutive articles about spiral shapes that I found curious:

{ Pasta-shaped radio waves beamed across Venice }

A group of Italian and Swedish researchers may have solved the problem of radio congestion by cleverly twisting radio waves into the shape of fusilli pasta, allowing a potentially infinite number of channels to be broadcast and received.

& { Scientists twist light to send data at more than 2 terabits per second }

A multinational team led by USC with researchers in the U.S., China, Pakistan, and Israel has developed a system of transmitting data using twisted beams of light at ultra-high speeds — up to 2.56 terabits per second.

Broadband cable supports up to about 30 megabits per second. The twisted-light system transmits about 85,000 times more data per second.

Is there something inherent to spiral shapes that allows them to hold more “information”? (I’m using the word info. in a general way, like if we think of the universe as a system of variously configured “bits” of info.) Is the relationship — in terms of information — between these technologies and natural constructs like DNA and galaxies more than an aesthetic correlation? If it’s true that spirals “hold more”, why is this?

P.S.
I’ve also asked this question at { Udacity }, if any of you are enrolled in Intro to Physics. I’ll re-post answers here if anyone answers there, and vice versa.

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ANSWERS:

{ memeengine }:

olena:

THE PHYSICS OF SPIRALS?

I’ve heard a little about that second item - use of “twisted” light in optic cables.  If you read my blog, you’ll know I’m no physicist, but I can offer my limited understanding…

Physically, I’m not sure if we’re talking about photons forming a spiral shape as they move.  It may have something to do with the polarity of the photons.  However, I think that what allows more information to be crammed in is something like different channels.

Even if it’s not completely accurate, I think that color is a good way for us amateurs to understand it.  You may know that white light contains all the colors of the rainbow (ie all frequencies of visible light).  Imagine if instead of sending one message in the white light, many messages could be encoded among the individual colors (frequencies) within the light.  So there could be a “red message”, a “green message”, etc.

The idea of twisting the light may have something to do with teasing apart the different frequencies, or channels so the individual messages can all be read.  Clearly, this has a multiplicative effect on the information that can be sent.

I think some of this research also looks at laying “meta-messages” on top of the normal light pulses.  Imagine if the rate at which the light pulses are sent were marginally slowed down or sped up.  This too can send information, and in theory, none of the original information from the pulses is lost (only perhaps marginally slowed).  Think of sending morse code by switching from intervals of slow pulses to intervals of quick pulses.

I know I’m not close to having a handle on this story in terms of the physics, but I think the above pseudo-examples capture the ideas of the more tightly packed information.  Hope this helps!

OS re: { memeengine }:

Thanks for answering! I wonder if DVDP’s image inspired that explanation? :D

Light can be twisted like a corkscrew around its axis of travel.

Optical Vortex }

It seems that just the actual wave, as it travels, is made to rotate as if it were going around the outside of a tube. I don’t know if that contradicts what you said —

“…I’m not sure if we’re talking about photons forming a spiral shape as they move…”

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Thyrm at { Udacity }:

Well, I can tell you that DNA coiled up can hold more information because its structure maximizes surface area while decreasing the volume that it occupies. If you were to uncoil DNA then it be about a meter long. If you unwrapped the two strands, then it’d be twice as long. Mind you, this is with one molecule of DNA that can easily fit inside the tiniest organelles of one of your cells. The geometry involved in that is beyond me. I am sure somebody else has a better answer.

Another amazing material that has a lot of surface area is activated carbon. Its surface area is absolutely insane, at about 500 sq. meters per gram.

Also, you might be interested in this: { http://en.wikipedia.org/wiki/Menger_sponge }

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{ hpgal3 }:

It could be something to do with the surface area. I remember seeing something on “Through the Wormhole” about the surface area of an object being where it holds most of its information (not its volume). This is true in biology as well, yes. Especially in folds, like your mitochondria and intestines. You just have more room.

http://www.youtube.com/watch?v=WbRvHbtB9AQ

Starts around 27:27

Historical events recede in importance with every passing decade. Crises, political and financial, can be seen for the blips on the path of progress that they usually are. Even the horrors of war acquire a patina of unreality. The laws of physics, though, are eternal and universal. Elucidating them is one of the triumphs of mankind. And this week has seen just such a triumphant elucidation.

Economist, The Higgs Boson: { Science’s Great Leap Forward }

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Well said.

People are asking, “What does this ‘God Particle’ mean for me? How will it change my daily life?”

The realistic answer is that it likely won’t. We’ve made it possible to live here (for now, although it’s not working out too well for us) in a “human bubble” and not care much about anything outside of human culture, human perspective, and how the rest of the world relates to us. It’s possible to go on living here and not give a damn about nature or science, because we don’t really have to encounter the former anymore, and can rely on others for the latter.

But should it be like that? I don’t know that there’s anything more sublime, more important, more vital than trying to know the world on its own terms. Once you’ve had a taste — a real taste — it’s near impossible to go back.

HIGGS BOSON!

superkrupaninja:

hadron94:

The moment is here! Feynman diagrams with fridge magnets!

Birthday present??

(via freshphotons)

Since the time of Newton, we have been told that actually the table, like all matter, is a colorless cloud of particles moving in empty space. There is no table, really, and there is no color; color is produced by the action of particles on your nervous system. Of course there isn’t really a nervous system either. There isn’t really a you. We are non-things in a world devoid of any of the properties “we” seem to experience it as having.

Alva Noë, “A Little Philosophy is a Dangerous Thing”

via { npr }