Freeman Dyson: Is a Graviton Detectable?
ฝัง
- เผยแพร่เมื่อ 9 ม.ค. 2014
- Invited talk at the Conference in Honour of the 90th Birthday of Freeman Dyson, Institute of Advanced Studies, Nanyang Technological University, Singapore, 26-29 August 2013
www.ntu.edu.sg/ias/upcomingeve...
Publication:
Is a graviton detectable?
Freeman Dyson, Int. J. Mod. Phys. A, 28, 1330041 (2013)
www.worldscientific.com/doi/ab... - วิทยาศาสตร์และเทคโนโลยี
Friends, you are watching a legend of humankind. Just think, here is a man that at 90 years of age, while most of his peers are retired enjoying themselves, has traveled to Singapore to bless people with knowledge.
Thank you,
World Scientific Publishing for sharing this video. Dyson is a brilliant theoretical physicist. It's somewhat sad to see him at ninety struggling with simple phrases. On the other hand, it's great to see him talking about a subject that people sixty years his junior would struggle with. All the knowledge is in Dyson's head, it's simply that as he has aged it has become harder to articulate his thoughts. He will be aware of this himself.
For those who follow Einstein, gravitation can be explained as space-time curvature due to matter. Matter tells space-time how to curve! If gravitons should be detected, surely this would not bode well for General Relativity. Such force carrying particles (if we equate them to photons in classical EM theory) would obviate the necessity for a curved space-time due to matter. I find it inconceivable that the presence alone of gravitons would so neatly "fit the bill" as Einstein's field equations do in describing curvature of space-time.
Thanks once again for affording me the pleasure of seeing and listening to this brilliant man.
AJJ, One might naturally attempt to use the correspondence principle when passing from the quantized graviton to the "classical" gravitational waves. General relativity contains nonlinearities which will complicate things, which was one of the sources of difficulties for Feynman in his attempt to quantize gravity in his book on the subject. Nonetheless, one would expect gravitons to extend the applicability of classical GR to the quantum realm, not replace classical waves; just as in the case of photons and EM.
Holy Moly it's complicated !!
I had a lot of difficulties coping with degree-level mathematics
Thank you for posting this wonderful talk.
Man I hope there are more like him coming down the shoot.
Sadly there aren't in this era
That would be “chute”.
@@ticketforlife2103 Anyone considering following in his path should watch his "TH-cam Memoirs" of 157 video clips th-cam.com/play/PLVV0r6CmEsFzDA6mtmKQEgWfcIu49J4nN.html and will se how his interest in this began at a very early age,
where he and like minded friends calculated wheir way through advanced books on math that they happened to find in a library, and learnt russian to understand some volumes.
LOL!@@wiltonsmith3397
One of the greatest applied mathematicians who has ever lived
14:22
Just to note that in the 2nd volume of Fuller’s ‘Synergetics’ (published 1982 MacMillan-Collier) there exists a passage where he describes the process how a ‘spent’ radiant particle ‘turns’ and becomes integral with that ‘unit’ which is gravity. (Not myself in a position to comment.)
One of the greatest scientists
Is gravitation a detectable removing of distance process of some type? Does distance get removed at a rate or instantaniousy?
Does empty space telescope in some way like a telescoping antenna?
Gravity seems to remove less distance at the square of the distance from the gravitation.
Brilliant. Period.
So, hypothetically you would need a Dyson sphere to detect even one Graviton...
John Nibarger: Yes,when Feynman talkes about local action with regard to the moon orbiting earth he points out it takes the shortest path. Space time is not pushed away by a planet otherwise it wouldn't fall towards it, therefore it must be stretched, taking a straight line between them. It is not just curved at that point it's stretched; there is less of it so where does it go. It's almost as if matter eats space. Clearly a spinning electron in the classical sense must have some effects on the space that surrounds it, and recent observations have shown that the earth does twist space in this regard.
If spinning twisted space, I would think space would drag Earth's rotation to a halt unless there is no inertia in the distortion of space. If there is no inertial, then would gravity waves propagate at an infinite speed?
bill coop rather than saying the matter “eats” space, it might be better to say that matter DEFINES air INFLUENCES space.
It would have been interesting if Dyson had explained how to enjoy and understand equations. graphing them is one way.
This guy is a badass.
Was
just a question: has been ever detected the gravitational force of a single particle? is there any paper about an experiment detecting it, saying as conclusion "we measure that the gravitational force of the electron is .... newtons?
lol...
yes, any 'object' on a table is gravity in real time. Concerning particle coliders, following newtons cannon theory. If you have a particle colider that stretched around the world and sent a single proton through it, yes, you would see gravity in action and eventually drive the proton to earth.
I always thought that the only way to make artificial gravity in weightless conditions is by the help of centrifugal-power, but if you make a sort of pad that emits gravitons at the objects that are supposed to have a local gravitational attraction at them. Would that work as the artificial gravity in the spaceships in Star Wars looks like?
What have I misconceived how these particles are supposed to work? Please respond!
force carries partiqels can not just be made.
Yet
I think the reason a theory of quantum gravity is so intractable is people underestimate the complexity involved. It may turn out that quantum mechanics has nothing to do with it and even using the word "quantum" in quantum gravity is misleading. It kind of looks like the conceptual difference between classical mechanics and quantum mechanics will be the same size difference between quantum mechanics and -quantum- [insert better description here] gravity.
What would removing distance do to equations or make happen?
Depends on the mechanical function you are acting to perform. Goes sum zero gravity, that breaks into the "standard model." Particle to macro mass applicable. Spooky action "moves" all. Emission to absorption. Transfers to E=mc^2
Dear Rs
FEAR ME
Although I dislike the idea that Gravity is the warping of Time/Space, I may have just killed its competition the graviton.
If Dark Energy (the expanding of space) can out power gravity then wouldn't a Black Hole do so as well? If Time stops in a Black Hole and even Photons can not escape the event horizon, why would we expect that a Graviton could?
You and I are thinking; Apples vs. Oranges right? Now reconsider how Dark Energy works and Time/Space moving FTL into the Black Hole.
Thus I am forced to conclude that the warping of Time/Space works for a Black Hole and Gravitons do not.
Please reply. I'm not a heater or a fighter. I'm jut a guy with a thought.
Jeff B General Relativity is a tricky subject if you really contemplate it; after all...it is a relative phenomena and yet we are trying to inject it into universal applications.
What if time as a perception of spacial iterations is similar to gravity; that it is a proximity displacement effect within space and not a force reaction of matter?
Let us consider that existence is not space; and that space itself is the state of nothing (relative to matter/energy); and where the nothing of space is the medium which all potential matter/energy must or can exist...and that the vacuum or medium of space is displaced by the existence of matter/energy because where there was nothing, there is now something...which this spacial displacement would act more like water than stretched fabric. However, in the mental experiments of fabric of space or in displacement, we must not confuse ourselves with effects of gravity experienced on earth as relative to either the fabric or medium of space.
The displacement of space medium would then create a displacement 'pressure' upon matter/energy; gravity. The center of gravity is the center of mass or the center of greatest spacial displacement.
Other bodies or objects either on and within the body or in close proximity would be affected by the displacement pressure being 'pushed' toward the center of displacement; center of gravity.
A second body would create its own spacial displacement, thus its own spacial displacement pressure and relative to the proximity to each other, these two bodies would be affected or pushed together, more forcefully the closer they were.
Essentially there would be a lower spacial displacement pressure between the two bodies relative to their mass and proximity.
Mass density would affect this phenomena because all matter contains space; yet matter contains less space the more dense it becomes meaning the true spacial displacement is greater in dense matter.
Therefore, gravity would not be a pulling force caused by matter/objects; but would be the reaction caused by matter in space where space is literally pushing inward toward the center of gravity or the center of displacement of spacial vacuum.
If gravity was able to be viewed as a stretchy fabric that affected matter and energy, then spacial displacement seems a better explanation because it explains center of gravity; proximity of gravity; gravity relative to mass density and why as an apparent force it provides so many anomalies unexplained in general.
It also continues to be consistent with affects of gravity on light; where light passes close/through a spacial displacement...the closer to the center of displacement/gravity, the more affect on the light.
And where black holes theoretically exist in which such dense matter/mass existed, the displacement would be exponentially orders of magnitude greater.
NOW: for graviton / geometry...that is explained relative to wave particle duality; universal wave function and string theory.
John Nibarger Are you following me? :)
I still don't like it, even with alterations. Could there be two gravitational forces, sure? I can't really prove anything one way or another. Might Dark Matter be a third force? We just don't know yet.
Was I out of line with my "killed the Photon" remark? Rethinking it with the mind set of there being more then one Gravitational force; I may have jumped to a conclusion that is less sustainable then I thought at the time I made the statement. (Thank you again for making me think)
Pertaining to your last paragraph, My gut tells me that Quantum Field Theory is the best of the Hypothetical Sciences.
Fields may exist that have the potential for a particle that in nature might never or seldom occur. How would we know? Imagine the possibilities. The graviton may be one of these particles; unnatural but producible, with the right stimulus, from its field. Not unlike our new friend the Boson.
Keep in touch. I really don't like to share what I really think because some will still my ideas and the rest will think I'm nuts.
"Could there be two gravitational forces, sure?"
If gravity is an effect, not force; an interaction of space and matter/energy...then there may be an untold number of 'gravity' forms since gravity would not constitute a fundamental underlying force, but would be a circumstantial effect interaction.
I think that Quantum Field Theory and modern physics has essentially dispelled the myth that space is nothing; that the vacuum is absent everything.
My view has always supported field and string theory where the vacuum of space is 'nothing' (in the sense of matter/energy as observed/experienced and interacted with)...this nothing is in fact 'something' (exists) and everything which materially exists does so within some form of it (the medium).
I thus ask the question: What would prevent gravity from being the simple 'effect' of matter/energy present within space? If matter/energy and space cannot coexist within the same field coordinate (where something exists, nothing is displaced)...can gravity be simply explained as the unbalanced pressure of space vacuum which seeks to reoccupy the area previously occupied as nothing?
In oversimplified terms...why does gravity have to be a 'force?' Why can gravity NOT be spacial displacement?
It would seem in explanation of cause effect that spacial displacement far better explains the actual force-like nature of gravity and why two bodies affect each other as well as why we on the surface of earth are apparently 'drawn' toward the center (which is the center of displacement).
I realize this complicates other areas people have worked on...but the complication is ONLY relative to them having injected gravity INTO the unifying theories or equations and now all prior believed 'progress' is somewhat disturbed if gravity must become an OUTPUT and not a coefficient input.
And IF GRAVITY is an effect / interaction from space pressing upon matter, then the effects of gravity on time lead us to think about time differently.
If gravity is not a force and universal (meaning gravity only exists in the presence of matter/energy within space, for example) then time does not exist without matter/energy...and if time only exists when matter/energy is present in space...it is an effect and the observation of those effects become artifacts of observation.
I have not seen anything which would refute or necessitate how/why gravity cannot be related to this spacial displacement...nor why time must be fundamental either.
In fact, from my thoughts on the matter...if gravity and time are interaction outcome effects, it seems to actually simplify things (albeit that it really is an uncomfortable thought which is counter to our experience and historical beliefs about gravity and time).
electrons are INSIDE protons and neutrons Dear Freeman........... so doing a SINGLE electron from the nucleus is SMALLER gravity than that to knock OUT a larger proton or neutron. the surrounding UP quarks would ABSORB the gravity wave and thus not ALLOW the larger to escape UNLESS the gravity wave was SO large and such a size would do lots of damage long before getting to us.
determining the difference between EARTH the sun the moon and planets VS extra solar gravity is VERY difficult indeed. what makes it semi-possible is gravity OUTSIDE the solar systemtraveling EITHER in a SPHERE OR linearly in a plane STRETCH OUT as the surface volume AWAY from the source stretches OUT..... and so would be LONGER that the closer sources of nominal gravity....... I have sorted at LIGO site. and often wondered at the potential accuracy due to (wavelength X volume)......... rather than wl/volume you can see the direction wavelength would go.....
gravitons are not photons besides we just need to effect it not detect them sides theres a difference between hopeless and impossible yo just have to be really really really creative
I agree with your statement
So now the ChiComs have samples of Dyson's genome. :(
Aliens are saying “ they think it’s their science that isn’t good enough for us but it’s their politics “
Really interesting. If graviton doesn't exist, then all string theory is just innecesary (the origin of the ST was precisely finding string states with spin 2, gravitons). The problem seems trying to use techniques of QFT useful for the electromagnetism, weak and strong forces, but that don't work on gravity. Why trying to quantize gravity?? isn't more easy to think that particles are just there acting according to QFT rules, but they don't gravitate?. So gravity is just a macroscopical description. Just like temperature: fast moving particles inside a box are the origin of the temperature you detect, but a single particle has no temperature.
Some people are indeed thinking about Gravity as an emergent, macroscopic phenomenon.
Even if such speculations are on the right track, there are several problems with similar ideas. The most obvious is that gravitational and inertial mass are identical ( equivalence principle/ General Relativity).
Particles ( like electrons e.g.) have mass/ energy, so they must gravitate, even if their effect is tiny...
One possible answer is that this equivalence is only a good approximation at the macro level, but then where's the "dividing line"?
Particles like neutrons do seem to be sensitive to the gravitational field, though.
Summary:
Is a Graviton Detectable?
-Not with the methods proposed so far.
Does it mean gravitons do not exist?
-Maybe, but we cannot be sure.
Is quantum gravity wrong?
-We don't know.
However, there is a new proposal for the search for gravitons in a recent paper co-authored by Lawrence Krauss: “Using cosmology to establish the quantization of gravity,” published in Physical Review D (Feb. 20, 2014). Krauss and Wilczek suggest that gravitons might leave their mark on cosmic background radiation. That is a possibility that was not contemplated by Dyson in his lecture.
Dr. Dyson talked about the fact that terrestrial detectors cannot detect gravitons (nor can earth size detectors near a bigger gravity source than the sun). Those are the only direct empirical possibilities for verification of the existence of gravitons. On the other hand, what Krauss and Wilczek suggest in their paper is that we use the entire universe as a detector, looking for the effects of gravitons in the cosmic background radiation.
This is an exciting possibility that almost singlehandedly revives the search for gravitons in the near future. The great thing about the proposal is that we don't need to create a costly experiment to prove their existence. A series of cosmological observations will do.
CRT
So no news then , thanks for saving me 38 mins
You are welcome.
Star Trek Theory
Much obliged.
If gravitational wave exists we would be experiencing it daily if not weekly from a source 1AU from earth produced by solar bombarded by mass ejection/explosion of material into the corona sphere
I don't get why a detector for gravitational waves (LIGO) would be expected to detect quanta of gravity (graviton), that's not its purpose...
..as it turns out, there was a paper published with the confirmation of gravitational waves and in it was a highlighted section stating that if a g-wave becomes distorted it would be more than likely due to the zero rest mass of gravitons
Then you don’t “get” Quantum Theory, either. You might try viewing some of David Bohm’s discussions of Quantum Theory. You’re in good company, though.... even Einstein had his problems with Quantum Theory and tried to convince us that he knew God’s thoughts & behaviors ...
GBuckne référence, please?
Yes, in fact Dyson says LIGO and "that kind of apparatus" in theory can't detect gravitons, even if it were run at top theoretical abilities. 10:24
@@nmarbletoe8210 Kip Thorne did mention that some calculations were done where a limit was put on the hypothetical graviton, that would suggest that gravitational waves are propagated by the graviton, which is predicted in the standard model...
Life experiences... Always listen to your elders.
13:00 conversion of photons to gravitons!
also 40:50
The 3rd. Coulomb's law of static charges is identical to Newton's universal law except for a constant of proportionality and of course a sign. But to ignore this fundamental similarity of gravity and E&M, is an example of how particle physics is a science in crisis... discovering smaller and smaller quantities of ... energy, not really particles.
+Erixoz lol
My friend u don't even know how many 1/r^2 types of laws exist in physics. It is not a property of the force, it is the result of studying interactable potential fields. When you differentiate this potential you get a force term.
What Freeman claims is that gravity is a classical force, while quantum particles like electron, proton etc., does not have gravitational force fields.
DD claims that is not true. Can anyone explain, please?
Naimul Haq They do possess gravitational fields but plug in the values of mass and the relative distances between electrons/protons, protons/protons and you'll see that the force is so small it tends to zero and might as well not be there.
Would a graviton distort time too?
DumbledoreMcCracken a graviton might BE time!!
@@dougr.2398 Then can we measure the quantization of time? A classical 'clock' that counts, and stores a record of those counts, very quickly? Zetta counts per second? Such thing could be a photon spewing cannon on a turntable. Obviously, that wouldn't work, but could something?
DumbledoreMcCracken are you confusing gravitons with photons? I think Freeman has done that before halfway through. He said “according to Planck”, the energy is h(bar) omega. However, Planck was not considering gravitons, but was discussing light.
DumbledoreMcCracken someday we might find that time is quantized..... but not yet
@@dougr.2398 Humm. That is above me. I proposed to use the emission rate of a rotating photon source, perhaps a pulsar, to paint on a screen (say the surface of a planet) photons. If the photons are painted in discrete solid-angle pixels (with some Gaussian distribution), as the machine ratchets to the next instant in time, then that might indicate the resolution of time (quantitation). This idea doesn't work (I think), but I wonder if someone else has a better method.
Interesting, but dated. LIGO has since detected multiple gravitational waves. Also, quarks have not only been observed in the LHC, but have seen to diverge from the predictions of the Standard Model. But Dyson is obviously a seminal mind in 20th century physics, and had an intelligent, if flawed insight into the workings of our universe.
about quarks, Dyson was specifically talking about single quarks being hard -- or impossible -- to observe.
so, have single quarks or deconfined quarks been detected? is that anything to do with a quark gluon plasma?
@@nmarbletoe8210 it is my understanding that at those scales visual observation is impossible because we are unable to see something without a photon or electron interacting or bouncing off it. All the particles that have been observed at the LHC are essentially identified as energy signatures as most of them exist very briefly.
Actually now gravitational wave is observed.
As long as grav wave exists, graviton exists like EM wave Vs photon.
yes, it is now finding many events!
no for right now. it is not detectable, but you can use a graviton particle field, for propulsion. it like ion field propulsion
An interesting character was Dyson... I think Up Quarks quantise gravity via the strong mass spin force.. Even though electrons have a small amount of mass spin I do not think free electrons add to gravity directly, only when bonded in atoms.. Positrons may well have gravity as well as mass spin (spin is intrinsic fermion mass, not the electrostatic force, and Up Quarks are half 'strongly neutralised' positrons and Down Quarks fully 'strongly neutralised' electrons in most of my thought experiment universes, for what should be obvious reasons).. Up Quarks are Gravitons in the sense they quantise gravity, but they are no the force carrier of gravity, that's the unifying matter-energy subspace charge field.
I offer the following regarding the dual nature of light. Consider what is THE SUN. The sky is blue, and THE EARTH/ground is ALSO BLUE. The stars AND PLANETS are POINTS in the night sky. GREAT. E=mc2 IS F=ma. This explains the fourth dimension AND the term c4 from Einstein's field equations. BALANCED inertia/INERTIAL RESISTANCE is fundamental.
By Frank DiMeglio
well LIGO WORKED
... and out of it came a "no graviton" result arxiv.org/abs/1712.04437 which was actually issued in direct reply to this lecture. The No Graviton article -- published in CQG in 2018 August and pretty much settled the issue. That's not a "we found nothing because we can't see it" result but a "we *can* see it - *if* it exists - and found nothing" result. They described how LIGO is *already* able to see putative gravitons, but found nothing. Falsification of quantum gravity at its core. His "third possibility" 7:30 - on. The authors were being intentionally coy in their conclusion, but that's what they're really saying.
@@RockBrentwood I have a hard time believing the LIGO scientists can filter out all other vibrations so that they can detect a gravitational wave. Pardon my ignorance, but how can they be so certain that the vibration isn't from a dust particle that landed on the tube that enclosed the laser? Or a neutrino that struck a mirror to cause the fluctuation between the two beams? Can the designers of the LIGO be that precise that they can filter out all other noise so they can be sure that the vibration they detect is truly a gravitational wave?
@@daffidavit There are two LIGOs, one in Washington State and one in Louisiana. During the experimental run, a computer is continuously comparing the readings of both detectors. Both will report at the same time if a wave is detected. When only one reports something, it is treated as noise.
@@mikepatrick1904 Interesting. That lends credibility to the wave if its simultaneous to both detectors.
@@daffidavit When I googled "Freeman Dyson ligo" I found a single page letter by Dyson in a science publication, written shortly after the breakthrough discovery. He extolled Joseph Weber, who developed tests beds 50 years earlier, and claimed discoveries that no one could reproduce.
As long as we fail to measure 10^ -66 meter, we will not be able to verify/detect the existence of a graviton.
Graviton maybe can be real.
Perhaps gravitons curve space time, creating gravity. In other words, gravity may be a curvature in space time, but it also might be conveyed through particles, as predicted by quantum field theory.
Excellent overview on whether gravitons may be detectable. Sadly, World Scientific has a pricey pay wall preventing most persons from viewing Freeman Dyson's associated paper. These pay walls are holding back the advancement of world education and are quite harmful to the world.
Gravity is not hidden on the surface and it is hidden. But we feel the closest to it. If so, I would like you to officially authorize these two as elementary particles with magnetic field and magnetic force. They must be waiting for the leading role in the stage sleeves.Gravity has already been detected with our five senses.
GRAVITON HAVE ABILITY TO MOVE SPACETIME
Use Graviton Energy Field For Propulsion Let Say The Earth Has Positive Gravity Field Two Positive Field Will Repel Each Other And Negative Graviton Field Will Atract To A Positive Gravton
Field
The problem with Freeman Dyson's presentations, and this is a problem that many really bright people have, is that they can NOT "dumb it down" for their audience. This does a great disservice to those people who care not members of the cognoscenti who are well-versed in the arcana of their respective academic fields. GnowhatImeanmang?
John Karavitis eh... The level is probably perfect for the auditorium
I’m not classically trained and I understood everything he said. Of course I’ve been studying astrophysics for the past 30 years on my own. Maybe it’s starting to work. ⚡️
dude needs a tailor
Humza actually it is the tailors who need the dudes, relativistically thinking.... oh, Wait! They both need each other!! :-)
Humza you’d probably say Einstein needed a haircut, too! Their job is physical mathematics, or mathematical physics, not sartorial elegance
There is no such thing as a graviton.
Stating an opinion as a fact isn’t a method of establishing anything other than an opinion. It is the approach used by religion not science.
@@muttleycrew You are not correct either. Some people do believe the Universe is a God.
@@billymania11 You have not established that the universe is the same thing as a god by stating that some people think it is.
The unhealthy shake immunologically drain because ping orally decide onto a jealous attempt. wacky, untidy tray
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