Slowing the speed of light

Angleochoas

Angleochoas

Quantum Scribe
I was curious if anyone knows of any further application or experiment in this area;
http://www.news.harvard.edu/gazette/1999/02.18/light.html

If yes, what? If no, why?

As well, upon further investigation of the procedure, is it being taken for granted this is the only formula for truly doing this?
This changes the characterization of adjacent particles ("new matter") - is there a way to do it theorectically yet maintaining it's original form?
- That would be the kicker, it's interesting to see how "size" plays a factor here.
 
An entirely new state of matter, first observed four years ago, has made this possible. When atoms become packed super-closely together at super-low temperatures and super-high vacuum, they lose their identity as individual particles and act like a single super- atom with characteristics similar to a laser.

Such an exotic medium can be engineered to slow a light beam 20 million-fold from 186,282 miles a second to a pokey 38 miles an hour.
Click to expand...

The article is describing a BEC (Bose-Einstein Condensate), a form of matter that was predicted by Satyrenda Bose and Albert Einstein circa 1924.

That it "slows" light to a crawl isn't really so mysterious. Light travels at 300,000 km/sec in a vacuum. When it travels through matter it is slowed because the photons are absorbed and emitted by the electrons in the matter. Cool the atoms to as close to 0 Kelvin and they can be packed very closely. The photons are almost sure to be captured at an extremely high rate as the light passes through the condensed matter. How much it is slowed is a function of the Index of Refraction of the stuff it is traversing.

But...

The photons are still traveling at the speed of light, 300,000 km/sec, between emission and absorption. It is a vacuum between electron shells of the atoms.

Aside from BEC's there is at least one other extreme form of photons being "slowed". A photon emitted at the core of the sun should take just a smidge over 2 seconds to reach the surface. But it actually takes about a million years for it to reach the surface. Some quick math and you find that the average "velocity" of the photon is 0.000000000951 km/sec. Now that's a whole lot slower than 38 km/sec and the sun is definitely not cooled to near absolute zero Kelvin at the core. Of course the photons are traveling at the normal speed of light when they are not in the absorbed state...they just end up spending most of their time absorbed.
 
So as they "lose their identities" as single particles, are they in fact merging?
If so, what is really facilitating the formation; the photon or electron?
I am assuming that the state of "packing them very closely" would indicate inside the electron,
if that's correct - then upon the merging does the electron combine into this "new matter" ?
I would suppose so? Two photons joined without their identity would create a "larger" singular identity? - Not the topic of electron + photon ?

I guess when I try to visualize it - I'm wondering if the electron simply acts as a condenser to then release the "merged photons" from within; or if the electron is absorbed into the merging?
Would both ever be possible plausibly if this is not the case?

Simpler put, what happens to the electron after the reaction?
 
So as they "lose their identities" as single particles, are they in fact merging?
Click to expand...

That's a problem with reading articles written by non-scientists. Without reading the paper itself just what that means is pretty vague. Individual particles don't have individual identities in the sense that you can distinguish Neutron A from Neutron B for example. This is a basic principle of QM...indistinguishability of particles.

Do they actually merge? Close but not really. Its a QM statistical situation. The individual particles appear to weakly violate the Pauli exclusion principle in that their wave functions overlap as if they are sharing their wave functions. Some quantum behavior, which cannot normally be seen in our classical world becomes apparent at the macro scale.

The BEC is highly unstable. You can imagine that when cooled to near absolute zero Kelvin if you want to observe the BEC you have to shine some light on it. The photons, even very low energy photons, carry a huge energy component relative to the BEC which has virtually no external kinetic energy at near absolute zero. So just "looking" at it can supply sufficient energy to break the unstable symmetry and spoil the BEC.
 
It's interesting, because you once again remind me that there's so many possibilities held within the complexity.
Take the double slit experiment; we take for granted that the "act of observing" changed the outcome, whereas it is plausible that the "act of observing" in itself had physical environmental variables that caused such change, is it not?
IE;
Alot of people whom appreciate the experiments outcome, jump to the conclusion that the sense of sight and the brain's reception of the event caused the change to occur;
- when above originally I was speculating that perhaps the introduction of something physically in relation to where the apparatus was configured could cause such. (Introduction of a new power supply in close proximity for the "act of observing", more apparatus, etc, etc).
Perhaps beyond my scope of speculation, it could even be a combination of the two, to some degree?

----
As well, back to the original post reply - yes, I can appreciate that sometimes popular media must give an oversimplification for sake of basic grasp. I'm sure that sometimes can cause a few chuckles after reading some articles by some of you ^^
I also see how with alot of this, it's our own perceptions grasping something on a very broad spectrum of measurement almost to the brink of the brain grappling with finite vs. infinite for sake of relativeness. Though in regard to the function of particle vs. wave, is it not as in most things possible for both to exist at once, one function of duality being simply predominant under certain conditions?
(IE; The "insensible" shadow of the current function)
 
Angleochaos,

Good observation (excuse the pun).

Even among working QM physicists there is an ongoing debate about the complete meaning of what an observer is. In the fringe there is the metaphysical idea of how an observation event affects a quantum system. The far out metaphysical theories suggest that even thinking about a quantum system can cause it to change.

But when we just look at the physical meaning of observation we can understand why is causes a change in the system. We have to do something that equates to an input of energy into the system if we want to observe it. To observe such a system we have to "launch", at a minimum, photonic energy at the substomic particles we want to see. Now if we are attempting to observe a Mack truck with a few photons, or even a few billion photons, we won't noticably change the system (even though we really did change it to some infinitesimal extent). But if we are attempting to observe the state and behavior of a few electrons, launching photons at them involves energies and masses not much less than the electrons themselves. If we launch a VW Bug at a Mack truck we will substantially change the system. The mass/energy ratio is about the same. There really is no such animal as "passive uninvasive observation". If we "look" at a system we will change it.

Don't mistake this explanation for the actual complete QM explanation. I gave you a simple classical explanation. Beneath that explanation there are causes and effects that absolutely have no classical equivalent. Subatomic particles do not move and react like billiard balls. Billiard balls have well defined positions, masses, velocities, etc. Not so with quantum particles like electrons, protons and the like. We can only describe their evolution as a system with statistical maths. If we strike a billiard ball just right with the que we can say that there is a 99% probability that the ball will find the corner pocket. With subatomic particles all we can say is that if we make 100,000 observations of a system that one of the billion or so particles has a 99% chance of finding the corner pocket during any particular observation...but we have no idea which particle that will be. We can't even identify and differentiate one proton from any other proton (electron, neutron, meson, neutrino...). We can't guarantee that the particle that does find the corner pocket didn't "cheat" by quantum tunneling through the side rail, turning left and dropping into the pocket. Try that one with a billiard ball!

Subatomic particles do what they do and really don't care if we mear mortal humans don't understand how or why they act the way they act....sort of like teenagers as they view old farts. You know, adults over the age of 30.
 
I see what you are seeing/expressing.
My line of questioning then goes back to something I can't help but think is fundamental;
to define "observer" would we not have to find out something perhaps on some scales "larger" but at the same time more defining:
- If we truly believe in the existence (in whatever theorectical context), of parrallel time lines (paths of possibility through choice). Whether it be in terms of string theory, M-Theory, etc.
- Once experiments give credence to that then the more definitive terminologies would evolve?

I would imagine in QM that if an observation was an "one time" event being measured in terms of time with the scale of light, the term "observer" would hold much more significance rather than if we were to plausibly find that this "event" was a reoccurring "function" (regardless of cognitive conscious) - and the significance that would then place upon "observer".

Hard to express, I hope that gives some hand to metaphor.
 
Back
Top