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#660
by
Bob Woods
on 21 Jul, 2017 17:27
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FYI: Pions & Gravitons?
https://goo.gl/m7RhtP
free pdf of the article (the article is behind a paywall in the Nature link): https://arxiv.org/ftp/arxiv/papers/1703/1703.10682.pdf
This experiment concerns a solid-state flat-spacetime (no gravitons) analogue to a curved spacetime gravitational anomaly (the axial anomaly, responsible for the decay of a neutral pion into two photons. Similarly in a curved spacetime the axial-gravitational anomaly can give rise to the decay of the pion into two gravitons.). This experiment does not involve gravitons or actual detection of any gravitational anomaly in real spacetime.
https://www.ibm.com/blogs/research/2017/07/scientists-observe-gravitational-anomaly-on-earth/
Appearing in a paper published today in Nature, an international team of physicists, material scientists and string theoreticians, have observed such a material, an effect of a most exotic quantum anomaly that hitherto was thought to be triggered only by the curvature of space-time as described by Einstein’s theory of relativity. But to the surprise of the team, they discovered it also exists on Earth in the properties of solid state physics, which much of the computing industry is based on, spanning from tiny transistors to cloud data centers.
The experiment uses the mathematical techniques from string theory - but it doesn't prove anything concerning string theory as a quantum gravity theory of our universe. But it does validate some of the analytical methods used in string theory (string theory derived holography), which worked great for this particular physical material experiment in flat spacetime
https://arxiv.org/pdf/1610.04413.pdf
The authors of
https://arxiv.org/pdf/1311.0878.pdf
proposed this experiment precisely because the gravitational anomaly is considered to be impossible to probe in high energy contexts. It is really not possible (now or in the foreseeable future to our greatgrandchildren) to prove or disprove string theory (or its competitor theories of quantum gravity like quantum loop gravity) in a high energy context or to detect gravitons.
Thanks for the links Jose. I had not seen anything on this before today's article in the Times. It seems to me that this solid state discovery has potential for both research and applications. Only time will tell and hoping for a major breakthrough is what fuels the drive to discover and understand.
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#661
by
Space Ghost 1962
on 21 Jul, 2017 17:59
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FYI: Pions & Gravitons?
https://goo.gl/m7RhtP
free pdf of the article (the article is behind a paywall in the Nature link): https://arxiv.org/ftp/arxiv/papers/1703/1703.10682.pdf
This experiment concerns a solid-state flat-spacetime (no gravitons) analogue to a curved spacetime gravitational anomaly (the axial anomaly, responsible for the decay of a neutral pion into two photons. Similarly in a curved spacetime the axial-gravitational anomaly can give rise to the decay of the pion into two gravitons.). This experiment does not involve gravitons or actual detection of any gravitational anomaly in real spacetime.
https://www.ibm.com/blogs/research/2017/07/scientists-observe-gravitational-anomaly-on-earth/
Appearing in a paper published today in Nature, an international team of physicists, material scientists and string theoreticians, have observed such a material, an effect of a most exotic quantum anomaly that hitherto was thought to be triggered only by the curvature of space-time as described by Einstein’s theory of relativity. But to the surprise of the team, they discovered it also exists on Earth in the properties of solid state physics, which much of the computing industry is based on, spanning from tiny transistors to cloud data centers.
The experiment uses the mathematical techniques from string theory - but it doesn't prove anything concerning string theory as a quantum gravity theory of our universe. But it does validate some of the analytical methods used in string theory (string theory derived holography), which worked great for this particular physical material experiment in flat spacetime
https://arxiv.org/pdf/1610.04413.pdf
The authors of
https://arxiv.org/pdf/1311.0878.pdf
proposed this experiment precisely because the gravitational anomaly is considered to be impossible to probe in high energy contexts. It is really not possible (now or in the foreseeable future to our greatgrandchildren) to prove or disprove string theory (or its competitor theories of quantum gravity like quantum loop gravity) in a high energy context or to detect gravitons.
The experiment matters a great deal here. The theory attached is interesting to consider.
Suggest one does not get hung up concentrating on the theory, but the experiment and its ramifications. Theory will attend to itself.
Also, the role this might play in the interpretation of momentum/transients, especially in condensed matter ensembles, might be applicable here.
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#662
by
Rodal
on 21 Jul, 2017 18:02
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...
Thanks for the links Jose. I had not seen anything on this before today's article in the Times. It seems to me that this solid state discovery has potential for both research and applications. Only time will tell and hoping for a major breakthrough is what fuels the drive to discover and understand.
...The experiment matters a great deal here. The theory attached is interesting to consider.
Suggest one does not get hung up concentrating on the theory, but the experiment and its ramifications. Theory will attend to itself.
Also, the role this might play in the interpretation of momentum/transients, especially in condensed matter ensembles, might be applicable here.
Yes, Bob, it is very exciting, because this experiment was precisely proposed as an analogue of the gravitational anomaly that unfortunately we cannot test directly. I did not get the time to post it myself, and I very much appreciate it that you picked this up and posted it
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#663
by
Monomorphic
on 21 Jul, 2017 23:56
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Small spherical end-plate design with custom linear actuator coming along. I will be 3D printing the two main parts of the linear actuator. The rods are aluminum and the lead screw is stainless steel. There is ~1.1 cm of z axis translation. As soon as the new uninterruptible power supply (UPS) charges, I will begin printing.
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#664
by
Bob Woods
on 22 Jul, 2017 15:17
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Small spherical end-plate design with custom linear actuator coming along.....
And the linear actuator is for what? Shawyer bump? Antenna positioning? Photon Torpedo launcher?
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#665
by
Monomorphic
on 22 Jul, 2017 16:59
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And the linear actuator is for what? Shawyer bump? Antenna positioning? Photon Torpedo launcher?
The linear actuator is for moving the antenna along the z axis of the frustum. This is how impedance is matched to 50Ω. Before, I had to unscrew a nut and move the antenna up and down by hand. It was not very accurate and a lengthy process. With this new actuator, I will simply crank a knob. Much more accurate, and very quick.
Here is the completed actuator. It works very well. I was surprised at how easy it is to create custom parts with the 3D printer.
Edit: Also included a cutaway of the small end-plate to better illustrate how the linear actuator works.
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#666
by
Stormbringer
on 23 Jul, 2017 06:55
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look up articles or papers on weyl semimetals experiment showing gravity conservation symmetry breaking.
I would post a link to the article but its at NBF and folks get tetchy about excessive posting of NBF articles.
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#667
by
Monomorphic
on 25 Jul, 2017 12:33
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Finished the mold for the large end-plate quarter. I ran out of silicone for the small end-plate, but more arrives tomorrow.
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#668
by
Bob012345
on 25 Jul, 2017 16:31
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Finished the mold for the large end-plate quarter. I ran out of silicone for the small end-plate, but more arrives tomorrow.
Monomorphic, what material will the end plates be covered with on the inside of the cavity? Thanks.
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#669
by
Monomorphic
on 25 Jul, 2017 16:39
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Monomorphic, what material will the end plates be covered with on the inside of the cavity? Thanks.
EMI shielding copper adhesive foil will be used on the inside surface. This is the same material used for the lining of the side walls.
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#670
by
LowerAtmosphere
on 25 Jul, 2017 22:05
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#671
by
Tcarey
on 27 Jul, 2017 06:06
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Monomorphic, what material will the end plates be covered with on the inside of the cavity? Thanks.
EMI shielding copper adhesive foil will be used on the inside surface. This is the same material used for the lining of the side walls.
Mono.. I am curious about one thing. How do you bond the individual pieces of the copper foil electrically to form a single surface? Is the adhesive electrically conductive at microwave frequencies?
Thanks for what you do.
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#672
by
Monomorphic
on 27 Jul, 2017 12:48
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Mono.. I am curious about one thing. How do you bond the individual pieces of the copper foil electrically to form a single surface? Is the adhesive electrically conductive at microwave frequencies?
The adhesive is conductive at microwave frequencies. According to the spec sheet, there should be -75dB of attenuation at 2.45GHz. This was confirmed with measurements using a spectrum analyser. So for 43dB (20W) input, only -32dB (0.000000063W) will leak out of the cavity. A vast majority of the RF remains inside.
That being said, there is an increase in resistivity, but that is mostly a product of the thickness of the foil. There are other options such as silver conductive paint and electroplating, should there be any issues with the conductive adhesive.
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#673
by
yawan
on 29 Jul, 2017 00:25
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I’ve been thinking about quantum vacuum for a while now. This is the best I’ve come up with so far. I know it's not in line with standard theory, but it makes sense to me. Hopefully it will help someone.
Vacuum fluctuations are a sea of neutrinos and antineutrinos.
Pairs of them collide all the time. They produce another particle/antiparticle pair, either a new pair of neutrinos, two charged leptons, or a quark/antiquark pair. What you can produce depends on how much energy there is from the colliding neutrinos.
Now electrical forces affect these collisions, and that is how light gets propagated.
They are also the carriers of electromagnetic fields, since lack of electrons on one side and more of them on the other will create a disbalance in neutrino anti neutrino densities.
There are enough of high energy collisions to produce electron positron pairs quite often. This leads to the positron eating the electrons in orbit around atoms, and another electron from the pair creation taking its place. Since this process repeats itself every 10-18 s it look to us like the electron is in a thousand places at the same time. The more energetic the electron the more often this will happen, and the neutrino balance around the atom will be affected. This leads to high energy electrons acting like a probability around the atom, and to the electrons interacting with themselves forming strange looking orbits around the atom.
Around the nucleus of an atom the virtual neutrino cloud is denser. There are many more collisions and the probability of popping an electron/positron pair is higher. This creates a potential well around the atom. If the potential well is overcome there is fusion.
If we look at helium 2 for example, in case an electron positron pair pops up in the middle you will get neutron and beta decay. If that doesn’t happen in time atom will fall apart.
It's just a theory I’ve been working on. Can’t get the math right yet, but I’m interested to hear what other people think of it.
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#674
by
Monomorphic
on 30 Jul, 2017 13:17
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I had a problem with the small end-plate mold - it must have been a bad batch or I didn't mix it long enough as the mold basically started falling apart. So I went ahead and printed all of those parts over ~15 hours. The tolerance on these 3D printed parts is really good.
The large end-plate mold is still in pristine condition after three pours. It looks like that will turn out fine, but If I have to, I can print the remainder in ~45 hours.
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#675
by
WarpTech
on 30 Jul, 2017 16:42
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I had a problem with the small end-plate mold - it must have been a bad batch or I didn't mix it long enough as the mold basically started falling apart. So I went ahead and printed all of those parts over ~15 hours. The tolerance on these 3D printed parts is really good.
The large end-plate mold is still in pristine condition after three pours. It looks like that will turn out fine, but If I have to, I can print the remainder in ~45 hours.
Nice saucer section. The hole at the top is for the Bridge?
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#676
by
Monomorphic
on 30 Jul, 2017 19:54
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I was able to find CAD files of the various SMA connectors and nuts I have available. These are needed for the linear actuator that controls the z-axis position of the antenna. So that has been redesigned somewhat.
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#677
by
SteveD
on 30 Jul, 2017 20:12
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The large end-plate mold is still in pristine condition after three pours. It looks like that will turn out fine, but If I have to, I can print the remainder in ~45 hours.
I'm a bit torn on that. The cheaper and easier it is to reproduce the expirement the quicker things will progress.
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#678
by
X_RaY
on 30 Jul, 2017 20:56
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I was able to find CAD files of the various SMA connectors and nuts I have available. These are needed for the linear actuator that controls the z-axis position of the antenna. So that has been redesigned somewhat.
It is known that the 90 degree connectors produce high reflections. If this is possible please don't use this component.
There will be much lower reflection when you connect the coaxial cable direct to the straight SMA connector section.
However the tuning mechanism itself looks very great.
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#679
by
Monomorphic
on 30 Jul, 2017 21:05
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It is known that the 90 degree connectors produce high reflections. If this is possible please don't use this component.
There will be much lower reflection when you connect the coaxial cable direct to the straight SMA connector section.
Thanks X_Ray! Easy enough to eliminate the 90 degree angle connector. I can connect SMA cable directly to the jack.
