Extraordinary momentum and spin discovered in evanescent light waves

Mar 06, 2014
Transverse force and torque on a particle in evanescent field generated from a total internal reflection in a glass prism. These reveal the presence of the transverse momentum and spin in the evanescent wave above the prism. Credit: RIKEN

A team of researchers from the RIKEN Center for Emergent Matter Science (CEMS) in Japan has identified unexpected dynamic properties of a type of light wave called evanescent waves. These surprising findings contrast sharply with previous knowledge about light and photons.

The study carried out in the Quantum Condensed Matter Research Group (CEMS, RIKEN, Japan) led by Dr. Franco Nori is published today in the journal Nature Communications.

Energy, momentum, and are the main dynamic characteristics of physical objects. It is well known that propagating as an electromagnetic wave or photon carries momentum along the direction of the wave's propagation, and that this momentum is independent of polarization. In addition, light can carry an , called , that is proportional to the degree of circular polarization (helicity), and aligned with the propagation direction.

The RIKEN team analysed the momentum and spin of evanescent electromagnetic waves – a type of light waves that travel close to the surface of material objects and whose intensity decreases exponentially, rather than varying sinusoidally, from the interface where they were formed.

Surprisingly, the researchers found that evanescent waves carry momentum and spin components that are orthogonal to the direction of wave propagation. Moreover, the transverse spin turns out to be independent of polarization and helicity, while the transverse momentum is proportional to the wave helicity.

"Such extraordinary properties, revealed in very basic objects, offer a unique opportunity to investigate and observe fundamental physical features, which were previously hidden in usual propagating light and were considered impossible," says Dr. Konstantin Bliokh, first author of the study. "In addition to a detailed theoretical analysis, we propose and simulate numerically four novel experiments for the detection of the unusual momentum and spin properties of evanescent waves via their interaction with small probe particles," he adds.

These results add a new chapter to the physics of and spin of classical and quantum fields, and predict a number of novel light-matter interaction effects involving .

Explore further: Classical physics shown to be equal to quantum theory when it comes to unusual experiments with light beams

More information: Extraordinary momentum and spin in evanescent waves, Konstantin Y. Bliokh, Aleksandr Y. Bekshaev, Franco Nori, Nature Communications, 2014. DOI: 10.1038/ncomms4300

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User comments : 11

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gwrede
5 / 5 (3) Mar 06, 2014
Oh, boy. Seems there's no chance of physics "finding out everything" in my lifetime.

Which is good, IMHO.

Rimino
Mar 06, 2014
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Rimino
Mar 06, 2014
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Rimino
Mar 06, 2014
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Rimino
Mar 06, 2014
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dedereu
not rated yet Mar 06, 2014
They conclude :
"This allows the observation of 'impossible' properties of light and of a fundamental field-theory quantity, which was previously considered as 'virtual'."
This is not very surprising, because evanescent waves are essentially virtual, like tunneling trough a too high barrier, exponentially decreasing with the thickness, described by an imaginary time, which gives the exponential decrease.
This detailed study can be applied to radioactivity which is also a tunneling, neutrinos in matter, etc..
Propagation inside waveguides is longitudinal and can be evanescent and virtual.
Rimino
Mar 06, 2014
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Solon
not rated yet Mar 06, 2014
dense aether model.


I was thinking a nonlinear vacuum might allow for explaining much, and came upon this paper.

Magnetic and electric properties of quantum vacuum
Abstract.
In this report we show that vacuum is a nonlinear optical medium and we discuss what are the optical phenomena that should exist in the framework of the standard model of particle physics.

http://hal.inria....inal.pdf
Comments?

Bonia
Mar 06, 2014
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Bonia
Mar 06, 2014
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DonGateley
5 / 5 (4) Mar 07, 2014
@Bonia, ne Rimino: What computer program do you use to generate the random, meaningless shit you post? Nice words but they don't naturally combine in the way your program does it. It gives a naive appearance of being apropos something. Nice work.

Is there any way, however, to block bots like this? While exemplary nonsense generators, they really waste time and space relative to real physics content.
Rimino
Mar 07, 2014
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Rimino
Mar 07, 2014
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Rimino
Mar 07, 2014
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arom
1 / 5 (4) Mar 07, 2014
A team of researchers …. has identified unexpected dynamic properties of a type of light wave called evanescent waves. These surprising findings contrast sharply with previous knowledge about light and photons.
Surprisingly, the researchers found that evanescent waves carry momentum and spin components that are orthogonal to the direction of wave propagation….
"Such extraordinary properties, revealed in very basic objects, offer a unique opportunity to investigate and observe fundamental physical features, which were previously hidden in usual propagating light and were considered impossible," …

Unfortunately according to conventional physics, we still do not know the mechanism of light wave, maybe this new idea could help to solve the problem…
http://www.vacuum...21〈=en
EyeNStein
5 / 5 (4) Mar 08, 2014
Perhaps there should be a ban on clones who quote vacuum-mechanics websites instead of understanding the subject matter.
The evanescent waves in question are not propagating waves (Or else they would carry energy away instead of it being internally reflected.) Their momentum vector is therefore orthogonal to the normal. The Maxwell equation 'solution' for these exponentially decaying (as opposed to sinusoidal propagating) waves requires this.
I'm pleased that someone has measured these properties, even if they do keep talking about propagation of these non-propagating waves which makes the article confusing!
Bonia
Mar 09, 2014
This comment has been removed by a moderator.
EyeNStein
5 / 5 (5) Mar 09, 2014
There is no need to engage your superluminal gobbledygook generator.
The evanescent waves are a natural product of the Maxwell equations applied at the surface where total internal reflection takes place. The addition of the incident and reflected waves at the surface do not cancel out and the waveforms of those sinusoidal waves cannot become discontinuous.
The Evanescent waves are the Maxwell equation solution of the leftovers of that waveform addition at the surface. They are most certainly not superluminal.
Bonia
Mar 09, 2014
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Bonia
Mar 09, 2014
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Captain Stumpy
5 / 5 (4) Mar 09, 2014
when two electrons collide ...The mainstream physicists never ask such a questions.

@Zephir
about the above claim... CERN and other places like them are actually in the job of knowing such things to produce the fundamental physics that you are so quick to ignore for your AW/DAW philosophies

go here: http://physics.st...llisions

or here: http://www.physic...t=507758

note: just because they are not doing it now doesnt mean they haven't addressed the issue:
they HAVE thought/addressed this issue, as proven, which directly refutes your suggestion about how they "never ask such questions"

c'mon Zeph, this was a 2 second search!
2 seconds proves that your entire post was based upon personal conjecture and belief in pseudoscience and your scorn of modern physics due to your faith in DAW/AW
Bonia
Mar 09, 2014
This comment has been removed by a moderator.
EyeNStein
5 / 5 (4) Mar 09, 2014
You clearly have no grasp of even the basics of relativity: Your bogus example of two relativistic electrons communicating faster than light proves it.
Science has repeatedly proved relativity and disproved your 'aether'. The questions have been asked and answered. Why are you not listening?
Bonia
Mar 09, 2014
This comment has been removed by a moderator.
Captain Stumpy
5 / 5 (3) Mar 09, 2014
Nope, Stumpy - you even have no idea, what I'm talking about here

well Zeph, lets go back and fact check that statement:
you said
when two electrons collide with the 99% speed of light, could their repulsive charges apply, if their fields would propagate with speed of light only?The mainstream physicists never ask such a questions.

and I replied with
go here: http://physics.st...llisions

note: just because they are not doing it now doesnt mean they haven't addressed the issue:
they HAVE thought/addressed this issue, as proven, which directly refutes your suggestion about how they "never ask such questions"

now, given that the links DIRECTLY REFUTE YOUR CLAIMS that physicists "never ask such questions", then I believe it is "you even have no idea, what I'm talking about here" that is the issue, not that I dont understand- YOU DONT, or you miscommunicated what you meant

it took a whole 2 seconds to verify and I took the top 2 links
nice try
Bonia
Mar 09, 2014
This comment has been removed by a moderator.
Captain Stumpy
5 / 5 (3) Mar 09, 2014
Yep, you haven't understood the problem expressed in this experiment

@zeph
jumped to conclusions, eh?
I didnt ADDRESS that experiment, I addressed YOUR COMMENTS
which means that it is YOU who has the comprehension issue here, not I
but I told you already. Do you really believe, that this experiment is equivalent to mainstream experiments in LHC collider? If not, why you're linking it here?

I didnt say that they were equivalent, did I?
I think you are getting CONFUSED about whom you are posting to
I am not EyeNStein
I specifically posted above about your comments, which were WRONG
but then again, conjecture that is posted without checking facts usually is

you made a comment. I replied.
Re-read what I posted, and dont confuse me with EyeNStein
Bonia
Mar 09, 2014
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Bonia
Mar 09, 2014
This comment has been removed by a moderator.
Bonia
Mar 09, 2014
This comment has been removed by a moderator.
Bonia
Mar 09, 2014
This comment has been removed by a moderator.
Bonia
Mar 09, 2014
This comment has been removed by a moderator.