10KW LENR demonstrator (new thread)

[Betruger]

No e at the end of Quebecois, neither written nor spoken, unless you're specifically speaking (in french) about quebecker french language since the word for language is feminine in french and then that 'quebecois' adjective gets an e to match that.

[rcain]

BEC of photons was reported in nature last year.

Keep up with the literature people.

http://blogs.physicstoday.org/update/20 ... te-of.html

The BEC behavior of polaritons was reported in science in 2002.

i was just about to post the same.

here is the original paper in Nature - http://www.nature.com/nature/journal/v4 ... 09567.html

it says::

Bose–Einstein condensation (BEC)—the macroscopic ground-state accumulation of particles with integer spin (bosons) at low temperature and high density...

i dot think a laser can really be described as low temperature and high density. bicbw.

i'd be interested in that polariton paper if anyone manages to find it.

[Giorgio]

Again, seems you like to think that this is what I think, but I am writing something different.
If you don't get it than it probably means that we are using definitions that are too different to find a common ground of discussion.

Maybe so. I'm writing American, how bout you?

Scientific Anglo/American, with major focus on the "Scientific" part.

[Giorgio]

Ice is solid water, but to get it you need a specific level of temperature and pressure, or, if you prefer, you need a specific energy level of the surrounding medium to get solid H2O.
So no, ice IS NOT simply solid water, is the result of a series of preconditions without whom you will not have solid water.
Same goes for BEC and for the majority of physics phenomena known to date.

What would the Tc be for Photons? Since the equation contains a mass term in the divisor, and a photon's mass is zero, the Tc should be dang near infinite. (I'd say infinite but I suspect there are second order terms so... The equation also contains a PARTICLE COUNT term (not pressure) but since the mass is zero, the # term is fairly meaningless. With all the points that YOU have provided suggesting that a laser is a BEC, just not commonly called one, why does it upset you to think of it as one?

LOL, I am not suggesting anything, I am STATING some known and proved physics facts. YOU are making a big confusion with them and YOU are thinking that they suggest something else. That's quite a difference IMHO!

[Crawdaddy]

BEC of photons was reported in nature last year.

Keep up with the literature people.

http://blogs.physicstoday.org/update/20 ... te-of.html

The BEC behavior of polaritons was reported in science in 2002.

i was just about to post the same.

here is the original paper in Nature - http://www.nature.com/nature/journal/v4 ... 09567.html

it says::

Bose–Einstein condensation (BEC)—the macroscopic ground-state accumulation of particles with integer spin (bosons) at low temperature and high density...

i dot think a laser can really be described as low temperature and high density. bicbw.

i'd be interested in that polariton paper if anyone manages to find it.

The quote you mention must be from the preamble to the experiment. The actual photon BEC was measured at room temperature IIRC.

The quasiparticle BEC papers are in the references to the nature paper.

[Giorgio]

I'd really love to see a paper on a laser that operates from the ground state. That would be VERY interesting.

If you ever find one advise me in time so I can prepare popcorn and snacks to fully enjoy it as it deserves!

[ScottL]

Maybe so. I'm writing American, how bout you?

....America includes both North and South with quite a few languages.

Well you see there is
Latin American (Mexico and south (cept Brazil)
British American (which them Kanaks got ALL mixed up with Quebecoise, eh?)
And then there is American. Pretty much the entire world recognizes the term "American" as a language, though many might slip in the Canucks.

There is no such thing as "American" language. The U.S. version of historic english is merely a slang derivative of an already existing language with minor spelling differences. Every time I hear "speak American" or "Murrakin" I die a little inside. As for the Americas, yes several languages exist here and no the U.S. isn't "America." We have both Northern and Southern continents, although the U.S. population as some how misappropriated "American" as their own.

This will end my off-topic posting, back to Rossi and his fancy tea pot.

[Betruger]

I'm curious what other word you'd use as nationality adjective for citizens of the USA.. ?

[Giorgio]

BEC of photons was reported in nature last year.

Keep up with the literature people.

http://blogs.physicstoday.org/update/20 ... te-of.html

The BEC behavior of polaritons was reported in science in 2002.

That's not really a BEC of photons in the strict term of the BEC meaning.
Remember, a BEC is formed by a macroscopic population at ground state in thermal equilibrium.

This is more a statistical trick where you slow down some photons by dumping and reflecting them in a liquid dye, thus allowing them to reach an uniform temperature among the group. In reality they attain an average thermal equilibrium, but they have no macroscopic population and not at ground state.
This is more a new form of matter, a standing wave, or a new form of laser if you want, but not a BEC condensate of photons.

The main issue in attaining a BEC of photons is that when you try to cool down photons (i.e. you attempt to reduce their energy) all what you will get is that you lose them.
Why?
Because photons are not particles, they do not have different state of energies like particle do, they cannot jump from one state to the other.
Photons are excitations, they get generated or absorbed WITH different level of energies.
And this is exactly the neat trick they use in this research to try to create an uniform emission of photons all at the same energy level.
But again, no BEC of photons here folks.

[Betruger]

Rossi and his fancy tea pot.

- coffee pot.

[MSimon]

I'd really love to see a paper on a laser that operates from the ground state. That would be VERY interesting.

If you ever find one advise me in time so I can prepare popcorn and snacks to fully enjoy it as it deserves!

A physics blog guy was trying to explain it (the three state system) and had a diagram something like this :

Code: Select all

                  2======
                 /               \
               /                  \
        1==                      ==3

And called states 1 & 3 ground states. Which means state 3 is state 1. I knew right away the person explaining it wasn't clear on the concept.

You will have to imagine I did it correctly because the durned blog mangles spaces even with the "code" tag.

[icarus]

With all the points that YOU have provided suggesting that a laser is a BEC, just not commonly called one, why does it upset you to think of it as one?

For the same reason that a horse is not commonly called a cow.

BTW did you leave out a link to the laser without population inversion?

I'd really love to see a paper on a laser that operates from the ground state. That would be VERY interesting.

http://www.dw-world.de/dw/article/0,,6264884,00.html

http://www.nature.com/news/2010/101124/ ... 0.630.html

http://portal.groupkos.com/index.php?ti ... condensate

"Weitz has a couple of ideas for applications resulting from the research at the University of Bonn. Creating shortwave lasers in the X-ray or ultra-violet spectrum is one such idea.

Such shortwave lasers would be well-suited to the manufacture of computer chips as the process uses lasers to etch logic circuits onto semiconductor materials. The precision of shortwave lasers is superior to those with longer wavelengths, which would allow chip designers to create more complex circuitry on the same area of silcon."

A photonic BEC can produce coherent laser-like light, in vastly different spectrums to lasers and will thus be more useful to a wide variety of applications. Therein lies the essential difference between photonic-BEC generated coherent light beams and lasers: lasers are from tuned transitions between excited electron states and a photonic-BEC beam will be from the photons themselves being in a ground state trap.

[icarus]

BEC of photons was reported in nature last year.

Keep up with the literature people.

http://blogs.physicstoday.org/update/20 ... te-of.html

The BEC behavior of polaritons was reported in science in 2002.

That's not really a BEC of photons in the strict term of the BEC meaning.
Remember, a BEC is formed by a macroscopic population at ground state in thermal equilibrium.

This is more a statistical trick where you slow down some photons by dumping and reflecting them in a liquid dye, thus allowing them to reach an uniform temperature among the group. In reality they attain an average thermal equilibrium, but they have no macroscopic population and not at ground state.
This is more a new form of matter, a standing wave, or a new form of laser if you want, but not a BEC condensate of photons.

The main issue in attaining a BEC of photons is that when you try to cool down photons (i.e. you attempt to reduce their energy) all what you will get is that you lose them.
Why?
Because photons are not particles, they do not have different state of energies like particle do, they cannot jump from one state to the other.
Photons are excitations, they get generated or absorbed WITH different level of energies.
And this is exactly the neat trick they use in this research to try to create an uniform emission of photons all at the same energy level.
But again, no BEC of photons here folks.

You are wrong here because the maths says so.

From the Nature article:

Upon increasing the photon density, we observe the following BEC signatures: the photon energies have a Bose–Einstein distribution with a massively populated ground-state mode

I actually went through and checked Weitz's calcs, he is right, did you do the same?

BEC are described by the statistics of Bose-Einstein, (funnily enough) hence the name. This is THE definition of a BEC. The photonic-BEC is described by these statistics, thus it is a Bose-Einstein condensate ... any questions? (Or just go and do the math).

[Giorgio]

A physics blog guy was trying to explain it (the three state system) and had a diagram something like this :

Code: Select all

                  2======
                 /               \
               /                  \
        1==                      ==3

And called states 1 & 3 ground states. Which means state 3 is state 1. I knew right away the person explaining it wasn't clear on the concept.

You will have to imagine I did it correctly because the durned blog mangles spaces even with the "code" tag.

When I quote it becomes clear enough.
It does not surprise me, pumping and population inversion are seldom well understood, or probably are quickly forgotten after the "Laser's Physics" examination

[MSimon]

A physics blog guy was trying to explain it (the three state system) and had a diagram something like this :

Code: Select all

                  2======
                 /               \
               /                  \
        1==                      ==3

And called states 1 & 3 ground states. Which means state 3 is state 1. I knew right away the person explaining it wasn't clear on the concept.

You will have to imagine I did it correctly because the durned blog mangles spaces even with the "code" tag.

When I quote it becomes clear enough.
It does not surprise me, pumping and population inversion are seldom well understood, or probably are quickly forgotten after the "Laser's Physics" examination :)

Fortunately for me I was a college drop out after the first year. How does that help? I'm always worried that there is something I missed so I keep studying.