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orbital angular momentum of light (OAM)

J

Jamie M

Jan 1, 1970
0
Hi,

I read an article today about bouncing light off of a spinning object
and then detecting its rotation rate by measuring the reflected lights
orbital angular momentum. I had mentioned earlier that you could
produce light with orbital angular momentum by rotating an LED or laser
at a high speed, and I think this is the same effect but in reverse.

"Researchers find way to measure speed of spinning object using light's
orbital angular momentum"

http://phys.org/news/2013-08-orbital-angular-momentum.html

Also here's a new question! Can light with orbital angular momentum
cause an object to rotate, and how does that relate to the scale of OAM
of light going from zero OAM to infinite OAM?

cheers,
Jamie
 
G

Glenn

Jan 1, 1970
0
Hi Jamie

Somemany have written an article here:

https://en.wikipedia.org/wiki/Orbital_angular_momentum_of_light

It is incredible that no one has thought of that before.


Nov 1, 2012, physicsworld.com: Spooky action with twisted beams:
http://physicsworld.com/cws/article/news/2012/nov/01/spooky-action-with-twisted-beams
Quote: "...
Using this technique, Zeilinger and co-workers found they could obtain
differences in quantum number as high as 600 (in other words l = +300 on
one photon and l = –300 on the other). Lapkiewicz points out that there
is, in theory, no upper limit to a photon's l value, which suggests that
a photon – a quantum object – could acquire as much OAM as a macroscopic
object, leading to what he calls a "tension between the quantum and
classical worlds"
...."



Oct 19, 2012, physicsworld.com: Chip puts a twist on light:
http://physicsworld.com/cws/article/news/2012/oct/19/chip-puts-a-twist-on-light
Quote: "...
Indeed, he says that they aim to produce devices that can emit different
OAM values at the same time. This, he claims, could enhance
telecommunication bandwidth, by increasing the number of channels
available, and boost the power of quantum computers – devices, still
under development, that promise much faster data crunching by processing
multiple quantum states simultaneously. "Currently, quantum computers
rely on electron spin or photon spin, which only have two states,
whereas OAM has many states," he explains
...."


25 June 2012, BBC 'Twisted light' carries 2.5 terabits of data per
second:
http://www.bbc.co.uk/news/science-environment-18551284
Quote: "...
Recent work suggests that the trick could vastly boost the data-carrying
capacity in wi-fi and optical fibres
....
The idea is not to create light waves wiggling in different directions
but rather with different amounts of twist, like screws with different
numbers of threads
...."

University of Southern California (2013, June 27). Breakthrough in
Internet bandwidth: New fiber optic technology could ease Internet
congestion, video streaming. ScienceDaily:
Quote: "...
the technology centers on donut-shaped laser light beams called optical
vortices, in which the light twists like a tornado as it moves along the
beam path, rather than in a straight line
....
Unlike in conventional fibers, OAM modes in these specially designed
fibers can carry data streams across an optical fiber while remaining
separate at the receiving end
...."

/Glenn
 
G

Glenn

Jan 1, 1970
0
(answer to sci.electronics.design )

A radioamateur might have this question:

If a radio antenna radiate OAM-8 waves, how does the wavefront then look
like?

-

I radio beacon might radiate in angles equal the OAM in one frequency
only; e.g.:
0° = OAM-0
1° = OAM-1
....
180° = OAM-180
....
359° = OAM-359

or

0° = OAM-0
0.1° = OAM-1
1° = OAM-10
....
180° = OAM-1800
....
359.9° = OAM-3599

I do not know how the antenna system might look like - or if it even
feasible.

With 2 or more OAM enabled radio beacons an approximate position on
earth can be defined immediately.

-

If that is possible, a linear polarized wave can be used for longwave,
shortwave time signal that will also pinpoint where you are on earth. It
might be used for a new GPS, that can instantly make a approximate
position in 3D around earth or other planets.

https://en.wikipedia.org/wiki/Time_signal#Radio_time_sources

/Glenn
 
G

Glenn

Jan 1, 1970
0
(answer to sci.electronics.design )

(answer to sci.electronics.design )

A radioamateur might have this question:

If a radio antenna radiate OAM-8 waves, how does the wavefront then look
like?

-

I radio beacon might radiate in angles equal the OAM in one frequency
only; e.g.:
0° = OAM-0
1° = OAM-1
....
180° = OAM-180
....
359° = OAM-359

or

0° = OAM-0
0.1° = OAM-1
1° = OAM-10
....
180° = OAM-1800
....
359.9° = OAM-3599
....

Silly me, the angle encoding should of cause use gray encoding:
http://en.wikipedia.org/wiki/Rotary_encoder#Gray_encoding
Quote: "...
To avoid the above problem, Gray encoding is used. This is a system of
binary counting in which adjacent codes differ in only one position. For
the three-contact example given above, the Gray-coded version would be
as follows.
...."

/Glenn
 
G

Glenn

Jan 1, 1970
0
....

It violates the second law of thermodynamics, of course, so it will
almost certainly prove to be false.

Cheers

Phil Hobbs

In what way?

http://en.wikipedia.org/wiki/Anton_Zeilinger
Quote: "...
Anton Zeilinger’s achievements have been most succinctly described in
his citation for the Isaac Newton Medal of the Institute of Physics
(UK): “For his pioneering conceptual and experimental contributions to
the foundations of quantum physics, which have become the cornerstone
for the rapidly-evolving field of quantum information.” He is a pioneer
in the field of quantum information and of the foundations of quantum
mechanics. He realized many important quantum information protocols for
the first time, including quantum teleportation, entanglement swapping,
dense coding, entanglement-based quantum cryptography, one-way quantum
computation and blind quantum computation. In addition, he made many
important contributions to the conceptual and experimental foundations
of quantum mechanics, particularly in the areas of quantum entanglement
and macroscopic quantum mechanics.
...."


Science 2 November 2012:
Vol. 338 no. 6107 pp. 640-643
DOI: 10.1126/science.1227193
Quantum Entanglement of High Angular Momenta
Robert Fickler
Radek Lapkiewicz
William N. Plick
Mario Krenn
Christoph Schaeff
Sven Ramelow
Anton Zeilinger
http://www.sciencemag.org/lookup/doi/10.1126/science.1227193
http://www.sciencemag.org/content/338/6107/640.full
Quote: "...
In our experiment, polarization-entangled photon pairs (uncorrected
average visibility 97.99 ± 0.03%) at 810 nm were created using a type II
nonlinear crystal in a Sagnac-type configuration (26, 27).
....
The highest value of OAM per single photon where strong correlations
were still measurable was l = ±300 for both photons (Fig. 3C).
....
When we transfer one photon to high OAM values and keep the other in its
polarization state, the pair can be used to remotely measure an angular
rotation with a precision that is increased by a factor l relative to
the situation when only polarization-entangled photon pairs are used
(Fig. 4) (22).
...."


/Glenn
 
P

Phil Hobbs

Jan 1, 1970
0
In what way?

http://en.wikipedia.org/wiki/Anton_Zeilinger
Quote: "...
Anton Zeilinger’s achievements have been most succinctly described in
his citation for the Isaac Newton Medal of the Institute of Physics
(UK): “For his pioneering conceptual and experimental contributions to
the foundations of quantum physics, which have become the cornerstone
for the rapidly-evolving field of quantum information.” He is a pioneer
in the field of quantum information and of the foundations of quantum
mechanics. He realized many important quantum information protocols for
the first time, including quantum teleportation, entanglement swapping,
dense coding, entanglement-based quantum cryptography, one-way quantum
computation and blind quantum computation. In addition, he made many
important contributions to the conceptual and experimental foundations
of quantum mechanics, particularly in the areas of quantum entanglement
and macroscopic quantum mechanics.
..."


Science 2 November 2012:
Vol. 338 no. 6107 pp. 640-643
DOI: 10.1126/science.1227193
Quantum Entanglement of High Angular Momenta
Robert Fickler
Radek Lapkiewicz
William N. Plick
Mario Krenn
Christoph Schaeff
Sven Ramelow
Anton Zeilinger
http://www.sciencemag.org/lookup/doi/10.1126/science.1227193
http://www.sciencemag.org/content/338/6107/640.full
Quote: "...
In our experiment, polarization-entangled photon pairs (uncorrected
average visibility 97.99 ± 0.03%) at 810 nm were created using a type II
nonlinear crystal in a Sagnac-type configuration (26, 27).
...
The highest value of OAM per single photon where strong correlations
were still measurable was l = ±300 for both photons (Fig. 3C).
...
When we transfer one photon to high OAM values and keep the other in its
polarization state, the pair can be used to remotely measure an angular
rotation with a precision that is increased by a factor l relative to
the situation when only polarization-entangled photon pairs are used
(Fig. 4) (22).
..."


/Glenn

The black body formula, abundantly confirmed by experiment, relies on an
exhaustive enumeration of all the available states of the EM field, and
they don't include the orbital angular momentum states.

The equipartition theorem requires that in thermodynamic equilibrium,
all accessible states have the occupation number 1/(1+exp(h*nu/(k*T))).
If there were really all those extra states, black bodies would
radiate very much more intensely than they do.

So either (a) it's wrong, or (b) it's another Ultraviolet Catastrophe.
My bet is on (a). The quantum optics people have been ludicrously wrong
before now, e.g. the once firmly held claim that light from two
different sources could never produce interference fringes.

Cheers

Phil Hobbs



--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510 USA
+1 845 480 2058

hobbs at electrooptical dot net
http://electrooptical.net
 
J

Jamie M

Jan 1, 1970
0
Well, if it's all evanescent, big whoop. Everyone has known since
Fourier that if you include evanescent modes, you have a complete basis
set, so you can make anything you like. But it ain't too useful for
communication, even quantum communication.

That wasn't the claim being made back at the beginning of all of this
foofaraw.

Cheers

Phil Hobbs

Hi,

I think OAM and the relativistic hall effect could give a physical
description of E=mc^2 and physically describe the translation between
energy and matter maybe. Maybe matter is light with significant OAM,
and the relativistic hall effect asymmetry of its motion causes it to
curve into a toroid shape or other shapes that can be self sustaining.

cheers,
Jamie
 
J

Jamie M

Jan 1, 1970
0
Snipped some, but I like Maxwell,
https://en.wikipedia.org/wiki/Maxwell's_equations

his equations are based on _fluid dynamics _.
Now this is not my field, but when you mentioned that OAM
I try visualizing with water as medium.
Now I COULD imagine a rotating fan with a piezo beeper on it...

Sure, in the 'near by' (field LOL) the water would rotate a bit,
and for sure a similar propeller would also start rotating.
First thing that is clear here is that here will be a signal delay,
sound in water moves at a fixed speed (sonar), and when moving in spirals the sound
will be more delayed if spiral has more turns per unit of distance (cm duh).

So when moving away from such a [sonar] transmitter you will see timing issues.

Then I was thinking for sure if a professor starts thinking about this, then things will get more expensive,
and some of his students will be assigned to write papers for their PhD thesis about this,
and you can then staple (no that would be painful) so glue all those sheets of paper together
to make a nice big roll of tissue paper.
That will hurt trees and is not green at all, so here is also a political dilemma.
Then I was thinking if you do the same and send the rotating water into a tube (fiber),
maybe it will be seen to rotate over a longer distance (apart from friction etc).
But can this be used to send more information>?
Sure if it rotates faster or slower I am sure one of those papers will find a way,
but to find the rotation in degrees per unit of length over a distance where it
changes anyway, I think that would not be a very hope giving project.

From an aether POV it is interesting, and some of those tissues may be worth reading before use.
Anyways I am no expert on that, I just do not like photon,
kwantuum computahs are a hoax in my NSHO, and if there is any quantization it is on the level of the water molecules,
not of the level of our ping pong balls (electrons connected to atoms) connected to poles as detectors.
So, that was my 'Deep Thought' (not to be confused with that similar sounding movie) for this morning.


Standard ending of paper:
We Think This Reseach Has Brought The Quantum Computer So Much Nearer
With Additional Fundding And A Lifetime Of Research
Nuclear Fusion
Gravity Waves
Quantum Computer
OAM
??

Hi Jan,

Thanks for clearing that up!

cheers,
Jamie
 
(answer to sci.electronics.design )

A radioamateur might have this question:

If a radio antenna radiate OAM-8 waves, how does the wavefront then look
like?

You mean m = 8? Look here:

http://en.wikipedia.org/wiki/File:Helix_oam.png

and do the logical extrapolation.
I do not know how the antenna system might look like - or if it even
feasible.

Here's the general idea:

http://iopscience.iop.org/1367-2630/14/3/033001/article

See figure A4 and table A2, about 2/3 of the way down the page. The sidelobes aren't shown but it looks to me like they'll be, er, messy.

In a Q&A forum I can't find right now I asked Thidé if a piezo element inserted in the gap in the dish could real-time modulate the value of m, and he said "I don't know, we will have to try it".


Mark L. Fergerson
 
G

Glenn

Jan 1, 1970
0
(answer to sci.electronics.design )


More about OAM - it is useful:


Aug 5, 2013, Rotational Doppler shift spotted in twisted light
http://physicsworld.com/cws/article...tional-doppler-shift-spotted-in-twisted-light
"...
The team fired two beams of light carrying orbital angular momentum at a
rotating surface and showed that the resulting interference pattern in
the reflected light is related to the surface's angular velocity.
....
The frequency of the scattered beam with orbital angular momentum in the
same direction as the surface is raised slightly (blue-shifted), while
the frequency of the beam with angular momentum in the opposite
direction is lowered (red-shifted) by the same amount (see figure).
....
"I think it's quite unexpected and might be surprising that you have
this Doppler effect even though there is nothing that is moving closer
or farther from the detector," he says. "Of course, you can understand
it with hindsight by reasoning about the effect, but without this work
you would not expect it to occur."
...."

/Glenn
 
J

Jamie M

Jan 1, 1970
0
<http://en.wikipedia.org/wiki/Bo_Thidé>

The question is what OAM can be used for. It may work in fiber optics,
and some of the literature on "vortex launch" talks of OAM, and some
talks simply of avoiding the central defect of practical fiber (as I
had described in a prior thread).


Joe Gwinn


Well, if it's all evanescent, big whoop. Everyone has known since
Fourier that if you include evanescent modes, you have a complete basis
set, so you can make anything you like. But it ain't too useful for
communication, even quantum communication.

That wasn't the claim being made back at the beginning of all of this
foofaraw.

Cheers

Phil Hobbs



Hi,

I think OAM and the relativistic hall effect could give a physical
description of E=mc^2 and physically describe the translation between
energy and matter maybe. Maybe matter is light with significant OAM,
and the relativistic hall effect asymmetry of its motion causes it to
curve into a toroid shape or other shapes that can be self sustaining.

cheers,
Jamie

Snipped some, but I like Maxwell,
https://en.wikipedia.org/wiki/Maxwell's_equations

his equations are based on _fluid dynamics _.
Now this is not my field, but when you mentioned that OAM
I try visualizing with water as medium.
Now I COULD imagine a rotating fan with a piezo beeper on it...

Sure, in the 'near by' (field LOL) the water would rotate a bit,
and for sure a similar propeller would also start rotating.
First thing that is clear here is that here will be a signal delay,
sound in water moves at a fixed speed (sonar), and when moving in
spirals the sound
will be more delayed if spiral has more turns per unit of distance (cm
duh).

So when moving away from such a [sonar] transmitter you will see
timing issues.

Then I was thinking for sure if a professor starts thinking about
this, then things will get more expensive,
and some of his students will be assigned to write papers for their
PhD thesis about this,
and you can then staple (no that would be painful) so glue all those
sheets of paper together
to make a nice big roll of tissue paper.
That will hurt trees and is not green at all, so here is also a
political dilemma.
Then I was thinking if you do the same and send the rotating water
into a tube (fiber),
maybe it will be seen to rotate over a longer distance (apart from
friction etc).
But can this be used to send more information>?
Sure if it rotates faster or slower I am sure one of those papers will
find a way,
but to find the rotation in degrees per unit of length over a distance
where it
changes anyway, I think that would not be a very hope giving project.

From an aether POV it is interesting, and some of those tissues may
be worth reading before use.
Anyways I am no expert on that, I just do not like photon,
kwantuum computahs are a hoax in my NSHO, and if there is any
quantization it is on the level of the water molecules,
not of the level of our ping pong balls (electrons connected to atoms)
connected to poles as detectors.
So, that was my 'Deep Thought' (not to be confused with that similar
sounding movie) for this morning.


Standard ending of paper:
We Think This Reseach Has Brought The Quantum Computer So Much Nearer
With Additional Fundding And A Lifetime Of Research
Nuclear Fusion
Gravity Waves
Quantum Computer
OAM
??

;)

Cheers

Phil Hobbs

(Who is expecting to start a one-day-a-week gig in topological quantum
computing. Fun.)


Hi Phil,

Cool, I read about it - sounds feasible kind of, "electron liquid" with
quantized states appearing out of "no where", really interesting!
Sounds like a new state of matter being created. I guess you are using
graphene to avoid the low temperature requirements? (I was reading that
graphene may not need the low temperatures for the effect to occur).

I have a feeling it is a good way to learn about electrons by studying
this field! Pretty much unexplained though as I have read that the fine
structure constant value is still an unsolved mystery.

cheers,
Jamie
 
J

Jamie M

Jan 1, 1970
0
On a sunny day (Sat, 03 Aug 2013 15:44:57 -0700) it happened Jamie M

<http://en.wikipedia.org/wiki/Bo_Thidé>

The question is what OAM can be used for. It may work in fiber
optics,
and some of the literature on "vortex launch" talks of OAM, and some
talks simply of avoiding the central defect of practical fiber (as I
had described in a prior thread).


Joe Gwinn


Well, if it's all evanescent, big whoop. Everyone has known since
Fourier that if you include evanescent modes, you have a complete
basis
set, so you can make anything you like. But it ain't too useful for
communication, even quantum communication.

That wasn't the claim being made back at the beginning of all of this
foofaraw.

Cheers

Phil Hobbs



Hi,

I think OAM and the relativistic hall effect could give a physical
description of E=mc^2 and physically describe the translation between
energy and matter maybe. Maybe matter is light with significant OAM,
and the relativistic hall effect asymmetry of its motion causes it to
curve into a toroid shape or other shapes that can be self sustaining.

cheers,
Jamie

Snipped some, but I like Maxwell,
https://en.wikipedia.org/wiki/Maxwell's_equations

his equations are based on _fluid dynamics _.
Now this is not my field, but when you mentioned that OAM
I try visualizing with water as medium.
Now I COULD imagine a rotating fan with a piezo beeper on it...

Sure, in the 'near by' (field LOL) the water would rotate a bit,
and for sure a similar propeller would also start rotating.
First thing that is clear here is that here will be a signal delay,
sound in water moves at a fixed speed (sonar), and when moving in
spirals the sound
will be more delayed if spiral has more turns per unit of distance (cm
duh).

So when moving away from such a [sonar] transmitter you will see
timing issues.

Then I was thinking for sure if a professor starts thinking about
this, then things will get more expensive,
and some of his students will be assigned to write papers for their
PhD thesis about this,
and you can then staple (no that would be painful) so glue all those
sheets of paper together
to make a nice big roll of tissue paper.
That will hurt trees and is not green at all, so here is also a
political dilemma.
Then I was thinking if you do the same and send the rotating water
into a tube (fiber),
maybe it will be seen to rotate over a longer distance (apart from
friction etc).
But can this be used to send more information>?
Sure if it rotates faster or slower I am sure one of those papers will
find a way,
but to find the rotation in degrees per unit of length over a distance
where it
changes anyway, I think that would not be a very hope giving project.

From an aether POV it is interesting, and some of those tissues may
be worth reading before use.
Anyways I am no expert on that, I just do not like photon,
kwantuum computahs are a hoax in my NSHO, and if there is any
quantization it is on the level of the water molecules,
not of the level of our ping pong balls (electrons connected to atoms)
connected to poles as detectors.
So, that was my 'Deep Thought' (not to be confused with that similar
sounding movie) for this morning.


Standard ending of paper:
We Think This Reseach Has Brought The Quantum Computer So Much Nearer
With Additional Fundding And A Lifetime Of Research
Nuclear Fusion
Gravity Waves
Quantum Computer
OAM
??

;)

Cheers

Phil Hobbs

(Who is expecting to start a one-day-a-week gig in topological quantum
computing. Fun.)


Hi Phil,

Cool, I read about it - sounds feasible kind of, "electron liquid" with
quantized states appearing out of "no where", really interesting! Sounds
like a new state of matter being created. I guess you are using
graphene to avoid the low temperature requirements? (I was reading that
graphene may not need the low temperatures for the effect to occur).

I have a feeling it is a good way to learn about electrons by studying
this field! Pretty much unexplained though as I have read that the fine
structure constant value is still an unsolved mystery.

cheers,
Jamie

I was reading some more about the fine structure constant, and
apparently it isn't actually a constant but will changed based on
conditions, ie from wikipedia:

http://en.wikipedia.org/wiki/Fine-structure_constant

"While the fine-structure constant is known to approach 1/128 at
interaction energies above 80 GeV"

The mystery of the fine structure constant has been that it's value is
in a narrow range that allows for matter to exist, but this is looking
at it backwards, since if the fine structure constant can change (as
shown by the change in its value at 80GeV), then obviously it is
changing based on the conditions, so it will take on a value that
matches the conditions. So it's a variable.

cheers,
Jamie
 
P

Phil Hobbs

Jan 1, 1970
0
On a sunny day (Sat, 03 Aug 2013 15:44:57 -0700) it happened Jamie M

<http://en.wikipedia.org/wiki/Bo_Thidé>

The question is what OAM can be used for. It may work in fiber
optics,
and some of the literature on "vortex launch" talks of OAM, and some
talks simply of avoiding the central defect of practical fiber (as I
had described in a prior thread).


Joe Gwinn


Well, if it's all evanescent, big whoop. Everyone has known since
Fourier that if you include evanescent modes, you have a complete
basis
set, so you can make anything you like. But it ain't too useful for
communication, even quantum communication.

That wasn't the claim being made back at the beginning of all of this
foofaraw.

Cheers

Phil Hobbs



Hi,

I think OAM and the relativistic hall effect could give a physical
description of E=mc^2 and physically describe the translation between
energy and matter maybe. Maybe matter is light with significant OAM,
and the relativistic hall effect asymmetry of its motion causes it to
curve into a toroid shape or other shapes that can be self sustaining.

cheers,
Jamie

Snipped some, but I like Maxwell,
https://en.wikipedia.org/wiki/Maxwell's_equations

his equations are based on _fluid dynamics _.
Now this is not my field, but when you mentioned that OAM
I try visualizing with water as medium.
Now I COULD imagine a rotating fan with a piezo beeper on it...

Sure, in the 'near by' (field LOL) the water would rotate a bit,
and for sure a similar propeller would also start rotating.
First thing that is clear here is that here will be a signal delay,
sound in water moves at a fixed speed (sonar), and when moving in
spirals the sound
will be more delayed if spiral has more turns per unit of distance (cm
duh).

So when moving away from such a [sonar] transmitter you will see
timing issues.

Then I was thinking for sure if a professor starts thinking about
this, then things will get more expensive,
and some of his students will be assigned to write papers for their
PhD thesis about this,
and you can then staple (no that would be painful) so glue all those
sheets of paper together
to make a nice big roll of tissue paper.
That will hurt trees and is not green at all, so here is also a
political dilemma.
Then I was thinking if you do the same and send the rotating water
into a tube (fiber),
maybe it will be seen to rotate over a longer distance (apart from
friction etc).
But can this be used to send more information>?
Sure if it rotates faster or slower I am sure one of those papers will
find a way,
but to find the rotation in degrees per unit of length over a distance
where it
changes anyway, I think that would not be a very hope giving project.

From an aether POV it is interesting, and some of those tissues may
be worth reading before use.
Anyways I am no expert on that, I just do not like photon,
kwantuum computahs are a hoax in my NSHO, and if there is any
quantization it is on the level of the water molecules,
not of the level of our ping pong balls (electrons connected to atoms)
connected to poles as detectors.
So, that was my 'Deep Thought' (not to be confused with that similar
sounding movie) for this morning.


Standard ending of paper:
We Think This Reseach Has Brought The Quantum Computer So Much Nearer
With Additional Fundding And A Lifetime Of Research
Nuclear Fusion
Gravity Waves
Quantum Computer
OAM
??

;)

Cheers

Phil Hobbs

(Who is expecting to start a one-day-a-week gig in topological quantum
computing. Fun.)


Hi Phil,

Cool, I read about it - sounds feasible kind of, "electron liquid" with
quantized states appearing out of "no where", really interesting! Sounds
like a new state of matter being created. I guess you are using
graphene to avoid the low temperature requirements? (I was reading that
graphene may not need the low temperatures for the effect to occur).

I have a feeling it is a good way to learn about electrons by studying
this field! Pretty much unexplained though as I have read that the fine
structure constant value is still an unsolved mystery.

cheers,
Jamie

No, it's using low-TC SQUID ICs. Until my quantum mechanics is back up
to speed, I'm just going to be kibitzing and help solve implementation
problems. It'll be nice to have colleagues again.

Anyons for tennis? ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
 
J

Jamie M

Jan 1, 1970
0
Anthropic principle - if it didn't allow matter to exist, there would
be no physicists to natter about it.

Hi,

Thats the explanation I read before, really bad explanation.

cheers,
Jamie
 
J

Jeroen

Jan 1, 1970
0
Hi,

The fine structure constant really is a variable probably! So the
anthropic principle isn't necessary there. If its value changes only
a small amount even at 80GeV then you would have to go way back in
the universe to see an overall difference in its value I guess? They
are starting to check the CMB radiation to try to see if its value is
different there, but also they could do more accelerator experiments to
see what type of curve the fine structure "constant" follows at
different interaction energies maybe.


Since the fine structure constant is basically the ratio of the
impedance of free space and the quantum hall resistance, it contains
just c, e, u_o and h. Which of those would be variable? Oh, yes,
there's a factor of two in there too. That must be it. ;-)

Jeroen Belleman
 
J

Jamie M

Jan 1, 1970
0
Since the fine structure constant is basically the ratio of the
impedance of free space and the quantum hall resistance, it contains
just c, e, u_o and h. Which of those would be variable? Oh, yes,
there's a factor of two in there too. That must be it. ;-)

Hi,

Actually probably all of them except the factor of two :)

cheers,
Jamie
 
G

Glenn

Jan 1, 1970
0
Wrong statistics--Bose-Einstein is 1/(1-exp(h*nu/(k*T))). Same argument.

Cheers

Phil Hobbs

FYI:


Jul 2, 2013, Twisted light carries data over 1 km in optical fibre:
http://physicsworld.com/cws/article...light-carries-data-over-1-km-in-optical-fibre
Quote: "…
A new type of optical fibre that can carry "twisted" light over long
distances has been developed by researchers in the US, Israel and Denmark.

According to Ramachandran, who led the development of the fibre, the new
system is designed so that the phase velocities of the OAM modes are
different. This minimizes the probability of coupling between modes as
the signals propagate along the fibre.

This fibre is designed to carry four distinct modes – two zero-OAM modes
that propagate in the inner circular core and two OAM modes that
propagate in the outer ring. [PS: in the same kernel]

Development of the system that encodes and decodes the OAM pulses was
led by Willner at USC. Dubbed OAM mode-division multiplexing (OAM-MDM),
the system encoded data into four separate channels. These are defined
in terms of the OAM (0 or 1) and circular polarization (–1 or 1) of the
light. Using just these four modes, the team was able to transmit data
over a 1.1 km fibre at a rate of 400 Gbit/s.

The system was also able to reproduce each quartet of OAM modes at 10
different wavelengths of light – a technique called wavelength-division
multiplexing (WDM). This boosted the transmission rate to 1.6 Tbit/s –
the equivalent of transmitting eight Blu-ray discs every second. While
such data rates are routinely achieved by commercial WDM systems, this
is the first time that OAM-based transmission has been achieved over
distances greater than a metre.
…"

( New Optical Fiber Puts a Twist on Data Transmission:
http://www.photonics.com/Article.aspx?AID=54269 )

-

Science 28 June 2013: Terabit-Scale Orbital Angular Momentum Mode
Division Multiplexing in Fibers:
http://www.sciencemag.org/content/340/6140/1545.abstract
Citat: "…
Internet data traffic capacity is rapidly reaching limits imposed by
optical fiber nonlinear effects. Having almost exhausted available
degrees of freedom to orthogonally multiplex data, the possibility is
now being explored of using spatial modes of fibers to enhance data
capacity. We demonstrate the viability of using the orbital angular
momentum (OAM) of light to create orthogonal, spatially distinct streams
of data-transmitting channels that are multiplexed in a single fiber.
Over 1.1 kilometers of a specially designed optical fiber that minimizes
mode coupling, we achieved 400-gigabits-per-second data transmission
using four angular momentum modes at a single wavelength, and 1.6
terabits per second using two OAM modes over 10 wavelengths. These
demonstrations suggest that OAM could provide an additional degree of
freedom for data multiplexing in future fiber networks.
…"

-

Nature Photonics 6, 420–422 (2012), Optical communications: Multiplexing
twisted light:
http://www.nature.com/nphoton/journal/v6/n7/full/nphoton.2012.154.html?WT.ec_id=NPHOTON-201207

-

September 16-20, 2012, Orbital Angular Momentum (OAM) Based Mode
Division Multiplexing (MDM) over a Km-length Fiber:
http://www.opticsinfobase.org/abstract.cfm?URI=ECEOC-2012-Th.3.C.6
Citat: "…
Abstract We demonstrate the first MDM scheme using OAM states over
1.1-km of fiber. This is enabled by a SLM-based Mux/Demux setup, and a
fiber designed to propagate multiple OAM modes over km lengths. We
confirm low crosstalk (<-14.8dB) and multipath interference (<-19.7dB)
of this scheme by transmitting 400Gb/s QPSK data at 1550nm without MIMO
processing.
…"

br,

Glenn
 
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