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Science In the News / Re: Wireless Communication via Neutrinos
« Last post by Psydotek on March 31, 2016, 10:23:52 AM »
They're gonna do it!  Finally!

http://www.dunescience.org/

http://gizmodo.com/scientists-at-fermilab-are-about-to-start-shooting-neut-1768242281

Quote from: Gizmodo
Fermilab outside Chicago will soon begin its Deep Underground Neutrino Experiment (DUNE), and what it hopes to accomplish is as brilliant and confusing as the book of its namesake.

The experiment starts with accelerating protons close to the speed of light. That beam of super-fast particles is measured and then shot out through 800 miles of rock, where it will pop back up in South Dakota to be measured at the Sanford Underground Research Facility, home of the largest neutrino detectors on Earth.

All the data gathered by both facilities will be analyzed by a team of 800 scientists across 150 institutions. Hopefully some conclusions can be reached about not just the elusive nature of neutrinos, but about how stars function and even why matter exists. Regardless, the experiment itself sounds cool as hell.
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Physics questions / Re: Double Slit from a Photon's Perspective
« Last post by bobmath on January 07, 2015, 06:21:44 PM »
The thing is, in QM, photons don't have to move at the speed of light. It's just much more likely for them to do so, if they're traveling more than a really tiny distance.

That wikipedia article on Wheeler's delayed choice is pretty bad. It keeps talking about how "the photon decides whether to be a wave or a particle", which is nonsense because photons don't "decide" anything. They always act like photons (not waves or particles).
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Physics questions / Re: Double Slit from a Photon's Perspective
« Last post by threred on January 07, 2015, 10:42:30 AM »
A couple of links from where you sent me I ended up reading about massless particles (https://en.wikipedia.org/wiki/Massless_particle) which confirmed "...these particles must always move at the speed of light and hence do not experience time."

I've yet to read an article discussing the implications of this concept.

As for a description of Wheeler's delayed choice experiment, I just used wikipedia's page as my reference.

~R
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Physics questions / Re: Double Slit from a Photon's Perspective
« Last post by bobmath on January 05, 2015, 10:23:32 AM »
I don't think Ben has answered a question here in a while, so I'll just do my best Clippy impression and say, "it sounds like you're asking a question about relativistic quantum mechanics." Which I haven't studied. Time dilation is a special relativity thing, wave/particle duality is a quantum mechanics thing, and SR+QM=RQM.

On a related note, does anyone know where I can find a nonterrible description of Wheeler's thing? The ones I've found online are ridiculous.
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Physics questions / Double Slit from a Photon's Perspective
« Last post by threred on January 02, 2015, 11:14:04 PM »
In a couple of different episodes of TP, Ben has mentioned that when a photon travels from point A to point B, since it travels at the speed of light, from the photon's point of view the time is instantaneous.

He explained this by stating that as you go faster and faster towards the speed of light, relative clocks appear to slow down. So, travelling at the speed of light, as a photon does, all those clocks don't tick once, therefore no time passes for the photon.

I was thinking about this in regards to the double slit experiment - or rather variations such as Wheeler's delayed choice experiment.

From the photon point of view won't all of the experimenter's actions occur simultaneously? Has this idea been discussed anywhere? And what are the repercussions, philosophically or otherwise?

~R


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Oh yeah / CP violation song
« Last post by bobmath on December 11, 2014, 11:41:41 AM »
Heard Ben was doing a show on CPT symmetry violation, but have you done your research?
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The Titanium Physicists Podcast / Episode 51: Tabled Tops with Noah Zimmerman
« Last post by bobmath on November 04, 2014, 09:56:16 AM »
I don't eat bicycle tires. Why should I eat a little pink one?

So is it fair to say that the light and dark areas in a NMR image represent differences in the way the matter in that location responds to the "probe" magnetic field? (Exactly what differences are represented sounds like it could be very complicated.)

As far as actually constructing the image, one of your guests said that they're measuring a return voltage from the sample. It sounds like they're not using an array detector to pick up the entire image at once, but some kind of swept detector that picks up little bits of the image in rapid succession. (Maybe they're doing something Really Clever like exciting the sample with a series of Fourier basis functions and reading off the coefficients?)

Anyway, another great episode!
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Physics questions / Re: Acoustic Waves in CMB
« Last post by n8hanson on October 07, 2014, 01:17:25 PM »
Thanks, CthulhuKid,

I've read a bunch on the polarized patterns in the CMB and what that *might* mean. However, the acoustic topic was a little different. Here is a website that explains a bit about it:

http://www.astro.virginia.edu/~dmw8f/BBA_web/bba_home.html

But even here, I'm having trouble finding what the original source of the waves was. I can't tell if it is some kind of left over pressure waves from the Big Bang explosion (was it even an "explosion"?), or if it is tied directly to the temp. differences in the CMB (which I thought were the result of tiny particles popping in and out of existence).

Nate
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Physics questions / Re: Acoustic Waves in CMB
« Last post by CthulhuKid on October 06, 2014, 12:24:30 PM »
I'm not sure about the acoustic waves, but the gravitational waves made by the Big Bang were the subject of the cover article of October's Scientific American:

http://www.scientificamerican.com/article/how-big-bang-gravitational-waves-could-revolutionize-physics/

Might shed some light on your questions.
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Science In the News / Re: Bad Science Headlines
« Last post by CthulhuKid on October 06, 2014, 06:33:15 AM »
Thread Necromancy!   ARISE!

Just happened to stumble upon this blog which seems to be exactly about this subject.  Check it out, it's brand spankin' new, so there's only 3 posts as of today, but they're knowledgeable and funny:

http://lostclause.wordpress.com/2014/09/29/inaugural-post-couvade-syndrome/
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