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Tunneling

J

Jeroen

Jan 1, 1970
0
Hi Jeroen

Please explain this - single-photons - not photon clusters:


Markus Pössel: Faster-than-light (FTL) speeds in tunneling experiments:
an annotated bibliography:
http://www.aei.mpg.de/~mpoessel/Physik/FTL/tunnelingftl.html
Quote: "...An experiment of theirs, where a single photon tunnelled
through a barrier and its tunneling speed (not a signal speed!) was 1.7
times light speed, is described in Steinberg, A.M., Kwiat, P.G. & R.Y.
Chiao 1993: "Measurement of the Single-Photon Tunneling Time" in
Physical Review Letter 71, S. 708--711..."

Glenn

No such thing as single photons, either. All they do is to reduce
the light intensity until the average time between events from the
detecting device exceeds the lightspeed delay of the apparatus. They
then declare that there can never be more than a single photon inside
and marvel at the persistence of wave effects.

Light detectors are made of matter and the interaction of light and
matter is quantized. But that doesn't imply that light is quantized
by itself.

Jeroen Belleman


than is necessary for
 
G

Glenn

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

No such thing as single photons, either. All they do is to reduce
the light intensity until the average time between events from the
detecting device exceeds the lightspeed delay of the apparatus. They
then declare that there can never be more than a single photon inside
and marvel at the persistence of wave effects.

Light detectors are made of matter and the interaction of light and
matter is quantized. But that doesn't imply that light is quantized
by itself.

Jeroen Belleman

Hi Jeroen

These do not exist?:

http://en.wikipedia.org/wiki/Single-photon_avalanche_diode
Quote: "...
This device is able to detect low intensity signals (down to the single
photon) and to signal the arrival times of the photons with a jitter of
a few tens of picoseconds.
...."


January 25, 2013, Researcher achieves breakthrough in building efficient
single-photon detector:
http://phys.org/news/2013-01-breakthrough-efficient-single-photon-detector.html
Quote: "...
The single-photon detector is characterized by five convincing factors:
91% detection efficiency; direct integration on chip; counting rates on
a Gigahertz scale; high timing resolution and negligible dark counting
rates. Credit: KIT/CFN
...."


National Institute of Standards and Technology (NIST) (2010, April 16).
New detector counts photons with 99 percent efficiency. ScienceDaily:
http://www.sciencedaily.com/releases/2010/04/100415171525.htm

-

Apr 18, 2012, New single-photon source could boost quantum cryptography:
http://physicsworld.com/cws/article...hoton-source-could-boost-quantum-cryptography

15 April 2012, Electrically driven single-photon source at room
temperature in diamond:
http://www.nature.com/nphoton/journal/v6/n5/full/nphoton.2012.75.html

-

Centre National De La Recherche Scientifique (2007, April 2). Life And
Death Of A Photon 'Filmed' For The First Time. ScienceDaily:
http://www.sciencedaily.com/releases/2007/04/070402122514.htm
Quote: "...
A photon is an elementary particle of light. In general it can only be
observed when it disappears
....
The end result is that the atom changes to state 1 if the cavity
contains a photon and remains at state 0 if it is empty, as in the
standard method. However, this time the energy absorbed by the atom is
taken from the auxiliary field and not from that of the cavity. As a
result, the photon is still there after having been seen, and is ready
to be measured again
....
Suddenly the atoms appear in state 1, showing that a photon has been
trapped between the mirrors. The photon comes from the residual thermal
radiation which surrounds the cavity
....
The moments at which the photons appear and disappear reveal the quantum
jumps of light, which occur at random
...."

Glenn
 
J

Jeroen

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



Hi Jeroen

These do not exist?:

http://en.wikipedia.org/wiki/Single-photon_avalanche_diode
Quote: "...
This device is able to detect low intensity signals (down to the single
photon) and to signal the arrival times of the photons with a jitter of
a few tens of picoseconds.
..."

Yes, of course they exist. What they detect are not photons in the
sense of light particles, but discrete charges, electrons, dislodged
from the matter they are made of by the incident light waves. This
occurs with a probability proportional to the power density of the
local EM wave, provided its frequency is above a certain threshold,
characteristic of the detector material. This is by no means
proof that light itself is conveyed in discrete packets.

There exists no source of countable single photons at precisely
defined instants. All they do is to attenuate the light of a
picosecond laser by a sufficient amount to make the detector
produce one or fewer events per laser pulse on average. An APD
has huge gain. A sizable output pulse results from a single
electron-hole pair. The event rate has Poisson statistics,
convolved by the laser pulse shape.

Jeroen Belleman
 
G

Glenn

Jan 1, 1970
0
On 25/03/13 23.58, Phil Hobbs wrote:
....
Two nickel surfaces in contact will make a low-barrier tunnel junction.
Maybe a nickel cat's whisker?

Cheers

Phil Hobbs

Hi Phil

Please don't read this message right before you go to bed - it might
give you nightmares ;-)

-

Reminds me of:

Basic Information Regarding Tin Whiskers:
http://nepp.nasa.gov/whisker/background/index.htm
Quote: "...
Growth Mechanism(s): UNKNOWN!
....
Fundamental Research is INCOMPLETE
...."

http://nepp.nasa.gov/whisker/other_whisker/index.htm

Floating zinc whiskers strike at PC systems
Beware the frabjous crystals
http://www.theinquirer.net/inquirer/news/1036445/floating-zinc-whiskers-strike-at-pc-systems

Anecdote: Tin Whiskers Growing on Internal Walls of Transistor Can
(Vintage Radios):
http://nepp.nasa.gov/whisker/anecdote/af114-transistor/index.html

Metal Whisker Photo Gallery:
http://nepp.nasa.gov/whisker/photos/

Glenn
 
G

Glenn

Jan 1, 1970
0
Hi Jeroen

Can you also explain this?:


Jul 18, 2011, Light propagates as if 'space is missing':
http://physicsworld.com/cws/article/news/2011/jul/18/light-propagates-as-if-space-is-missing
Quote: "...
Kokaman's group has designed a way to control the dispersion of light by
manufacturing a metamaterial that has with a refractive index of zero.
....
"What we've seen is that the light disperses through the material as if
the entire space is missing," said Kocaman. "The oscillatory phase of
the electromagnetic wave doesn't even advance such as in a vacuum – this
is what we term a zero-phase delay."
...."

Glenn
 
G

Glenn

Jan 1, 1970
0
On 26/03/13 00.01, Phil Hobbs wrote:
....
Phase velocity vs. group velocity. There's an elementary theorem in
relativity that if you have FTL anything, causality goes out the window.

Cheers

Phil Hobbs

Hi Phil

Axiom of Causality is probably right ;-) :

Axiom of Causality:
http://en.wikipedia.org/wiki/Axiom_of_Causality
Quote: "...
An epistemological axiom is a self-evident truth. Thus the "Axiom of
Causality" implicitly claims to be a universal rule that is so obvious
that it does not need to be proved to be accepted. Even among
epistemologists, the existence of such a rule is controversial. See the
full article on Epistemology.
...."

Glenn
 
G

George Herold

Jan 1, 1970
0
A bit more data on them:-

http://goo.gl/Mwjkh

Can I use ebay as a supply chain?

There were a few US places that listed tunnel diodes with a
'request quote'.
I should order some... Say can I make a tunnel diode 'go' at ~3.8GHz?

We get some RF npn power transistors from Russia, used in discharge
lamp,
I think ~$20 each, at only 10 units a year, not worth a redesign.

George H.
 
G

George Herold

Jan 1, 1970
0
On 25/03/13 21.25, George Herold wrote:
...> Hmm that's OK except the last bit, The electron spending some time in

...

Hi George

Is it because of the standing space-time electron waves ;-)

Milo Wolff's Quantum Science Corner's: The Quantum Universe:

Quote: "...Actually, in the H atom both the electron wave-structure and
the proton have the same center. The electron's structure can be
imagined like an onion – spherical layers of waves around a center. The
amplitude of the waves decreases like the blue standing wave in the
bottom diagram. There are no point masses – no orbits, just waves...".

Atomic Orbitals:http://www.chemistry.nmsu.edu/studntres/chem111/resources/notes/atomi...

The Orbitron. a gallery of atomic orbitals and molecular orbitals on the
WWW:http://winter.group.shef.ac.uk/orbitron/

Glenn

Pretty much, electrons in an S state have a maximum at the origin, P
and the other higher angular momentum states have a node there.
(An electron in a p-state still has some probability to be in the
nucleous,
there's a small p-state hyperfine interaction. (for Rb ~100MHz, vs
6.8GHz)

George H.
 
G

George Herold

Jan 1, 1970
0
No such thing as single photons, either. All they do is to reduce
the light intensity until the average time between events from the
detecting device exceeds the lightspeed delay of the apparatus. They
then declare that there can never be more than a single photon inside
and marvel at the persistence of wave effects.

Hmm, we sell this single photon two slit apparatus. To confirm the
single photon part we pull out the slits, (except for the source
slit.)* factor in pmt efficiency and count pulses. There's some
probability that there is more than one 'photon' at a time.. but it's
small.

I didn't read the FTL paper, but certainly there's a defined
propigation velocity in the barrier region. (group velocity less than
c..I assume.)

George H.

*the trick, not invented by me, is a light bulb and green interference
filter.
 
G

George Herold

Jan 1, 1970
0
On 25/03/13 18.40, George Herold wrote:
...
So I have two questions;
Anyone know of a good review paper on low voltage zener physics.
And are there any tunnel diodes still in production?
Thanks,
George H.
Hi George
You can make/discover your own tunneldiodes - actually components with
negative differential resistance:
By Nyle Steiner K7NS 2001.
Zinc Negative Resistance RF Amplifier for Crystal Sets and Regenerative
Receivers Uses No Tubes or Transistors:http://www.sparkbangbuzz.com/els/znrfamp2-el.htm
-
Neon lamps can also function as amplifiers ;-)
Neon Lamp Tricks! Neon Lamp Multivibrator:http://donklipstein.com/sillyne2.html
Citat: "...This is an oscillator circuit using two neon lamps, two
resistors, and one capacitor..."
-
Solid state negative differential resistance components was discovered
several times about 100 years ago:
Cristadyne: Semiconductor archaeology or tribute to unknown precursors:http://www.a-reny.com/iexplorer/cristadyne.html
Quote: "...In 1923, Oleg Losev [O. V. Lossev, Lossew] (1903-1942) ( See
link below ) managed to make a high frequency generator using such a
detector. But it was polarized. This indicates that this diode had a
characteristic curve in which a negative slope was present. And this
makes one think of the tunnel effect diode invented a half a century
later...These layouts where part of what one called CRYSTADYNE [or
Cristadyne, Crystodyne ] systems. But in those days, the technical
performance and industrial ease of the new increasing valve technology
made these layouts to be ignored, and then forgotten..."
The Wireless World and Radio Review. October 1, 1924 and October 8,
1924: "The Crystal As A Generator And Amplifier" by Victor Gabel.
Radio News, September, 1924, pages 294-295, 431: The Crystodyne Principle:http://earlyradiohistory.us/1924cry.htm
Quote: "...SEVERAL  experimenters have observed that some contacts, such
as crystal and metal or crystal and carbon generally employed as
detectors may produce undamped oscillations of any frequency, exactly as
the vacuum tube oscillator. The same contact may also be utilized as an
amplifier. Oscillating crystals are not new since they were investigated
as far back as 1906 by well known engineers, but it was not until lately
that a Russian engineer, Mr. O. V. Lossev, succeeded in finding some
interesting uses for oscillating crystals..."
Radio News, September, 1924, page 291: A Sensational Radio Invention By
HUGO GERNSBACK:http://earlyradiohistory.us/1924sens.htm
Quote: "...Stated in a few words, the invention encompasses an
oscillating crystal...In other words, THE  CRYSTAL  NOW  ACTUALLY
REPLACES  THE  VACUUM  TUBE. That this is a revolutionary radio
invention need be emphasized no further. [Here Hugo Gernsback was way
ahead of his time]...We can not only detect with the crystal, but we can
also amplify with it...we can now also transmit with the Crystodyne,
and, as a matter of fact, a number of students in Russia have actually
sent messages with such sets over distances of more than three-quarters
of a mile during the past few months..."
Bell Labs The Transistor Other Claims to the Invention:http://www.beatriceco.com/bti/porticus/bell/belllabs_transistor1.html
Quote: "...This effect, he stated, was discovered by Dr W. H. Eccles in
1910, and remarked: It is hard to realize that it took about ten years
for practical active crystal-diode circuits to appear, in spite of
Ditcham's reminder circuits that included both RF and AF
amplification...Most of the credit for creating practical devices [of
this kind] goes to O. V. Lossev of Russia, whether or not he knew of
Eccles' pioneer work a decade earlier..."
Glenn
PS: Happy nutting...or neon lamping...
Hi Glenn,  Thanks,  I'm not so much looking for a negative resistance
device as I am for tunneling.
(If I had a tunnel diode on hand I'd want to look at the I-V curve at
very low voltage.. way before the first peak in current.)
Hmm maybe frustrated total internal reflection would be easier?
George H.

Two nickel surfaces in contact will make a low-barrier tunnel junction.
  Maybe a nickel cat's whisker?

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 nethttp://electrooptical.net- Hide quoted text -

- Show quoted text -

Really? Do I need a small contact area? (etched Nickel wire?)
Are there no oxides involved?
Are there magnetic field effects? (that could be cool.)
(I've always wanted a piece of Nickel.)
A few dollar tunnel diode might be better, making your own samples is
always messy.

George H.
 
G

George Herold

Jan 1, 1970
0
Phase velocity vs. group velocity.

Grin... Phase is such a slippery thing, always arriving before you
expect it.
(at least in filters)

George H.

There's an elementary theorem in
 
J

Jeroen Belleman

Jan 1, 1970
0
Hmm, we sell this single photon two slit apparatus. To confirm the
single photon part we pull out the slits, (except for the source
slit.)* factor in pmt efficiency and count pulses. There's some
probability that there is more than one 'photon' at a time.. but it's
small.

That device is deeply mysterious if you think of light as
discrete packets, because it requires them to be in many
places at once, while still ending up in one specific
spot in the end.

If you think of light as a wave phenomenon, with only the
detection process being discrete and probabilistic, it's
crystal clear what is really going on.

What experiment would demonstrate unequivocally that
light itself is conveyed by discrete photons?

Jeroen Belleman
 
G

George Herold

Jan 1, 1970
0
I don't see no negative resistance in figure 4.

Ahh, sorry I was looking for a current that is exponenetial with
voltage... so a straight line on the Log/linear I-V plot of figure
4. (Glenn got all excited about negative resistance... but that was
not my intent.)

George H.
 
G

George Herold

Jan 1, 1970
0
That device is deeply mysterious if you think of light as
discrete packets, because it requires them to be in many
places at once, while still ending up in one specific
spot in the end.

I agree! It is mysterious. But still one can count photons and see
the interference pattern build up with time.

If you think of light as a wave phenomenon, with only the
detection process being discrete and probabilistic, it's
crystal clear what is really going on.

What experiment would demonstrate unequivocally that
light itself is conveyed by discrete photons?

They do these "Heralded photon" experiements where parametric down
conversion creates two entangled photons. Then with two single photon
detectors you can see that a count in one channel 'predicts' a count
in the second (time delayed) channel. But all the detection is still
photons to electrons. And there is of course still some Quantum
efficiency that is less than one, and dark counts etc...

George H.
 
W

whit3rd

Jan 1, 1970
0
I had a request from a Physics Prof for Quantum Mechanics experiments.
“What sort of QM?”, I asked. (There being QM in almost everything
these days.)

“Tunneling”, was the reply.

I mentioned there was tunneling in low voltage Zeners...
I’m not sure how to ‘show’ that it’s tunneling though.

(A forward biased diode shows the same exponential I/V.)

A forward biased diode's exponential conduction is temperature-dependent.
The Zener diode isn't (much).

So, a temperature-cycling test will show the difference. Rotating
wheel and a heat lamp? Maybe balance a bridge with multiple forward
diodes, and show it doesn't have temperature-change drifts, then
do the same with Zener against diode?
 
G

George Herold

Jan 1, 1970
0
A forward biased diode's exponential conduction is temperature-dependent.
The Zener diode isn't (much).

So, a temperature-cycling test will show the difference.   Rotating
wheel and a heat lamp?   Maybe balance a bridge with multiple forward
diodes, and show it doesn't have temperature-change drifts, then
do the same with Zener against diode?

Yeah I thought about that. Check out figures 5 and 6 here,

http://www.nxp.com/documents/data_sheet/BZX79.pdf

For the low voltage ones the TC is about the same as a 'normal' diode
~ -2mV/K
(but becomming smaller at lower current???)
I read in Sze that the TC for tunneling is due to the change in band
gap with temperature.
(But I've forgetten what causes the TC in a normal diode... is it also
the band gap?)
Then you see in figure 6 that somewhere around a 6V zener you get +2mV/
K... and a 6V zener plus diode in series gives you a zero TC voltage
reference.

George H.
 
J

Jeroen

Jan 1, 1970
0
A Geiger counter.

Cheers

Phil Hobbs

I don't see a real difference in principle. The avalanche takes
place in a gas rather than in a solid. It detects charged particles
much more readily than gamma radiation, although it will do that too.

To detect gamma radiation, it has to hit something material and
the detection process is again discrete and probabilistic.
Good luck in performing the double-slit experiment though.

Jeroen Belleman
 
J

Jeroen

Jan 1, 1970
0
I agree! It is mysterious. But still one can count photons and see
the interference pattern build up with time.

That's my whole point! You are not counting photons, you're counting
ionization events which occur with a probability proportional to the
local EM power. At very low intensities, the interference pattern is
there, but it will cause detection events only occasionally. If you
really want to have photons, reserve the word for the amount of energy
that is exchanged between the field and a particle. At least that's
local and essentially instantaneous, doing away with all these
non-locality problems.
They do these "Heralded photon" experiements where parametric down
conversion creates two entangled photons. Then with two single photon
detectors you can see that a count in one channel 'predicts' a count
in the second (time delayed) channel. But all the detection is still
photons to electrons. And there is of course still some Quantum
efficiency that is less than one, and dark counts etc...

George H.

Is it really so mysterious that the EM waves created by parametric
down conversion have certain collectively conserved quantities?
A BBO crystal is basically an array of tiny non-linear harmonic-
injection-locked resonators. No need to think in terms of photons
to explain its operation.

Jeroen Belleman
 
G

Glenn

Jan 1, 1970
0
On 26/03/13 20.25, Phil Hobbs wrote:
,,,
A photon doesn't have enough of the required properties to qualify as a
'thing', i.e. something self-existent. It's an elementary excitation of
the EM field in a certain set of boundary conditions, not an object like
a rock or an electron. We've gone over this several times in sci.optics,
e.g. http://tinyurl.com/d23u5ek .

Cheers

Phil Hobbs

Truth about photons:

http://web.archive.org/web/20010605043443/zebu.uoregon.edu/~js/glossary/wave_particle.gif

Glenn
 
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