As the quantum detectors get more sensitivity they should be picking up fluctuations in the local gravitational potential and electromagnetic background fields of the earth. But I have not seen anyone running a detector continuously for the days or weeks or months needed to do the required correlations to trace things out. Nor, do I see anyone using time of flight (array imaging with speed of light and speed of gravity) to correlate and image and characterize sources.
For many years I have been tracking every new gravimeter design - traditional sensitive accelerometers, atom interferometer gravimeters, MEMS gravimeters, electrochemical gravimeters, electron interferometer gravimeters, Bose Einstein gravimeters, and many others. If I left out your favorite gravimeter (also gradiometer and other names), tell me and I will add it to my list.
The problem with most of them is they are too slow to sort out natural, man-made and purpose build signals. You need at least Msps (mega samples per second) which is 300 meters resolution for many global sources. But there are many ADCs (analog to digital converters) that can do Gsps (giga sps) for relatively easy correlations.
The seismometer networks pick up a small bit of gravitational noise, as do the magnetometer networks, as do many electromagnetic sensor networks. It is taking a long time for all the groups to sort out, mostly "not my job". But if there were some decent, low cost sensors that were sensitivity enough to track acceleration in real time (Gsps is real time for these sorts of things) maybe we could separate and characterize the sources.
I am writing to everyone, so some groups are very sophisticated but don't do practical things. And other groups have practical problems, but no time or resources for theory. And all the groups are struggling with sharing data and models, ideas and problems globally.
Anyway, I know there are lots of "quantum" and "condensate" and other devices out there that have noise. I am asking all the groups to share their noise and sort it out. Much of the "kT" noise is partly magnetic, partly gravitational and much human activity. It is possible to separate. But it means serious effort for global correlations. Now the radio telescope groups have "correlators" and seismic groups have their methods, and electromagnetic groups their methods, and gravitational groups their methods. But it is just one field.
Regardless. If you have noise that propagates at the speed of light and gravity, then all the other groups are picking up part, or all your signals too. If you are tracking signals propagating at acoustic speeds and particle speeds then you should also be checking the speed of light and gravity signals - because there are almost always couplings - that show up in correlations.
And, if you are one of those rare people who also check for instantaneous signals (or ones that are billions of times the speed of light scale) then there are screens and checks for those too.
But here I am particularly asking for those "quantum" groups who find analog signals in their devices when they try to reduce the size, increase the frequency, lower the temperature -- and all the thing people are doing to get to "nano", "pico", "femto", "atto", "zepto". "yocto" scale phenomena.
Please update your notes on noise. Those strong millivolt, microvolt and nanovolt signals are just the start of many levels of tracking noise sources. If you have distributed sources it looks more like diffusion than shock waves or pulses. The signal from an earthquake is going to propagate at the speed of light and gravity, but it is going to have cubic kilometers of source. It is trackable, but it needs low cost detectors of high sensitivity and high sampling rates - then the arrays can image and track the seismic waves. That is just one of many hundreds of outstanding problems that need better detectors. I am hoping some of the groups who have been pushing hard to make "quantum device" will take a few moments to look at their noise seriously and think of the practical applications and problems of using those for imaging.
The signal at a superconducting gravimeter is about 95% sun moon tidal signal. That is about +/- 1000 nanometers per second squared (nm/s2) at one sample per second (sps). And the remaining 5% is from the atmosphere and nearby water and a tiny bit of magma. There will be the usual magnetic noise and electromagnetic noise from nanoHertz to GigaHertz. But some of it is gravitational - at least it shows up as a signal in a gravimeter or gradiometer or direct gravitational potential sensor (time dilation, Mossbauer, LIGO type detectors).
A "good" gravimeter array can image the local atmospheric density, flows, radiation field. That is a strong signal. You can convert gravitational signals to magnetic units by using B = 38.7083 g, where B is in Tesla and g is in meters/second^2. The earth field, 9.8 m/s2 comes to about 379 Tesla. That is why gravity is so fine grained and powerful. And why it is so hard to make strong magnets in the fluctuating earths gravitational field.
The tidal gravitational field is fairly smooth, but it can also be turbulent. You are just as likely to see "flow noise" than "sparks" or "shocks" or "pulses". And lots of slow drifts and sudden changes of levels. It is not hard, but requires care and effort.
I have been at this for several decades. I take this unusual step of asking "anyone with noise" to contact me. If you have shielded your device from electric field variations, and done some magnetic shielding and still getting drift and variations, then it is "gravitational".
I can tell you the rough size at the surface of the earth. A lot of the "kT" noise is gravitational flow noise. It is actually moving at the speed of light and gravity but you only see the net as a slow motion. The potential is smooth and has tiny gradients. You can see the gradients fairly easily. The "grain" is about one 7 millionth the mass of the electron and the size is picometers. The ultimate grain is not as small as the Planck scale, but on the order of 10^-24 meters. For practical things it is only necessary to work at 10^-18 scale. But use them all and you don't have to stop at boundaries.
Electrons have mass, charge and magnetic moment - so they pick up electric, electromagnetic, acoustic and gravitational noise (signals if you know where it comes from). Just as electron paramagnetic resonance has advantages of higher speeds and greater sensitivity, so too does any electron or hole based device have advantages for detection and characterization of fast and tiny signals. I spent several years checking - the camera electron (or hole) wells are sensitive enough to use for detecting gravitational variations - and there are plenty of tiny escape events to work with. The same for all the memory devices - they are just small floating islands of a few electrons each. Sorting out the noise in the memory chips will help shrink those down to single electron charge levels and below.
It is possible to image the atmosphere with gravitational arrays. Since I am lumping magnetic and gravitational fields together now, that means any combinations of "gravimeters" or "magnetometers" or "electromagnetic (from nanoHertz to PetaHertz or more). Moving sensors get a synthetic aperture advantage. So if someone would boost the GRACE type satellites to monitor the motion of electrons at Gsps rates we could get clear, real time images of the earths interior. Likewise moving sensor detectors arrays for volcanoes, ocean currents, density variations, magma and other things. The "moving" can be from seismic or natural vibrations, just measure it carefully for correlations and corrections. It jinks the position of the sensor so you can use subpixel methods. Deliberate movements are fine, but random but measured ones work too.
Richard Collins, Director, The Internet Foundation
Of course you would since all named are possible local hidden variables. Quantum fluctuations are the biggest noise along with fermion spin and neutrinos, all of which could also roil the background field and could be perceived as noise.
Forrest Noble I asked this question long ago, but did not get a notification that you answered.
I very much dislike the term "local hidden variables" because I found that most everything can be traced. Some of the noise in an electronic circuit labeled as "local", is in fact, "gravitational", or "magnetic" or "electromagnetic" or "infrasound" or "seismic" or "gravitational waves". I went to the trouble to find all the global sensor networks, just to see how much "nonlocal" noise there was in the devices deliberately used as sensors. But also in ordinary devices like camera image sensors, flash drives, dynamic memory chips. And I also looked for correlations between the sensors in what are now still mostly separated sensor networks - seismometers, gravimeters, magnetometers.
I would have to go back in my notes. A woman was working on seismometers and commented that her northern seismometers had a lot of magnetic noise. I checked the seismometer data and found about 20 different phenomena that are recorded along with the earthquake consequences. They can be directly operated as gravimeters. But they also pick up the same atmospheric gravitational "noise" that the super conducting gravimeters see. There are infrasound detectors that can be operated as good seismometers. I saw this in so many "single purpose" global sensor networks, I started to look at it globally for all sensors.
Now I have known for some time that image sensors such as used in cell phones can pick up some cosmic ray events. And, at some level - if the sensitivity of those sensor is carefully monitored, they can be used (because of their large numbers of data points, more bits per reading and higher and higher frame rates - as magnetometers (electrons have magnetic moments), as gravimeters (electrons have mass), and as electromagnetic sensors (electrons have charge). That - using image sensors and memory chips (floating capacitor designs particularly) seems to be a way to make universal sensors that can gather and report on local, regional, global, solar system and universal field changes. And the way to improve sensitivity for all sensors is to correlate them locally, regionally, globally, solar system wide and universally in a more deliberate and collaborative way.
The particular experiments with "quantum" sensors are quite a mix. Even though I see and read and study many of them, I only see general similarities. I know that the designs and methods used are also used in other fields, for other purposes, and almost always for precise measurement of fields and signals. So I have lumped all the "quantum experiments" into "communications" and "detection" for now. And have been encouraging them all to try to correlate the signals from continuously operating "quantum" devices used as "detectors" to see if they are picking up "gravitational" "magnetic" and other signals that are often recorded and well understood by some global and regional networks.
Part of the reason I did that is because I have been searching for almost two decades now for better gravitational sensors for imaging arrays. An operating particle accelerator has to correct for earth tides now for new designs. So if that earth tide correction process is inverted, the whole accelerator can be considered a detectors. All the seismometers (normally reporting velocity) can also report acceleration and thus can be used as gravimeters when the sensitivity becomes great enough and the sampling rate high enough.
I did look particularly at "Bose Einstein" gravimeters. There are purpose made gravimeters, but any "Bose Einstein" devices is a quantum detector and could also report changes in gravity, or in electromagnetic fields. The "Mossbauer" gravitational potential sensors (it uses time dilation so it measures changes in the potential first and gradients in arrays), and many derivatives of "atomic clocks" which "quantum" methods are used more broadly. They can be used for their original purposes as well as for "quantum" purposes.
The only difference between a laboratory "Big G" or "quantum" or "nuclear magnetic moment" experiment" and a "gravitational" use of the same equipment - is "continuous measurement".
I use "quotes" a lot. Because when I am searching the whole Internet for things it use exact strings to narrow the field often. Rather than general searches, I many many hundreds of very specific searches and combine them into broader topics. For the Internet Foundation, I try to index and organize all knowledge and things posted on the Internet. And tie that content and groups into global processes, issues, initiatives, projects, and systemics. It is not something to do lightly. I have been doing that every day for 25 years, and I feel I have a rough sense of how all that electronic data works.
The issue of "quantum" I asked about here, and have been working on almost daily since, is that some of the best minds are hammering on "quantum". Often to gain market share, or pre-eminance. But eventually some of the things people build for experiment or for other purposes - encryption, communiation, faster than light communication - whatever their stated purpose - the "noise" in their devices, because of the sensitivity, could perhaps be correlated with the many existing sensor networks also used to understand and 3D image our world and the fields that make it up.
That is roughly what I asked. And I will NOT trivialize it to "hidden variables". With effort (and I mean sometimes years or decades or lifetimes) most of these things can be tested, recorded, shared globally and made into routine measurements that benefit all.
I have said essentially the same things to LIGO, to the Large Hadron Collider groups, to all the individual single purpose sensor network groups - "your sensors and experiments are now at the sensitivity and ability to record, so that they pick up much more than your local purpose. Your "noise" is almost always a mix of other groups "signals". Further, I say, "Do not throw away your "Newtonian noise" or your "low energy events" or "1/f trash". Record it, share it, study it, if you don't have time, post it on the global Internet and there is likely someone who will study it. Just taking the top 40 single purpose data streams, that is 40*(40-1)/2 = 780 pairs of interactions. And there the self interactions (same sensors but different groups or location) are where the "intra-network" comparisons and correlations go. Those are really high priority, but not very often done as thoroughly as they ought.
Richard Collins, The Internet Foundation
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