edguy99

To me, this is the most important feature of the planck length: For every length, you can determine two energies, one for a photon (of that wavelength) and one for a black hole (of that Schwarzschild radius). At the Planck length, those two energies will be equal. At longer lengths, the black hole will be more energetic than the photon. At shorter lengths, the photon is more energetic than the black hole. One can check it out using these three formulas: E=Mc^2, E=hc /lambda (photon energy) R =2G M/c^2 (Schwarzschild radius for black hole) In layman's terms, the smaller the wavelength the more energetic the photon. At the planck length, the photon is so energetic, that the mass equivalent is a black hole.

From last weeks jlab conference, check out slide 9 of the 9:45 Friday presentation https://www.jlab.org/indico/event/209/

An infinite amount of energy is required to get a particle with mass (electron/proton..) to travel at the speed of light, but massless particles (energy in the form of photons) zoom along at the speed of light with no problem. "Physical significance"? Purely as a thought experiment I will try an example. Consider a different way to think of this issue. You are using energy to make the particle move faster and energy moves at the speed of light. Could you get an object to move as fast or faster then then the object you are throwing at it? You could if the collision was "elastic" like a pool game where the balls bounce off each other. What about if the collision was "in-elastic" where the colliding particles stick together? In the words of Einstein: "Radiation carries inertia between emitting and absorbing bodies". It is important that not only does something receive a "kick" from the momentum of the energy, but the internal inertia (i.e., the inertial mass) of the body is actually increased. ie. the collision is "in-elastic". Now, think about shooting a machine gun at a chunk of lead and assume the chunk of lead absorbs the bullet. As you shoot, the chunk of lead starts to move faster because of this and gets heavier. You will never get the chunk of lead to move at the speed of the bullet, it will move faster and faster, get heavier and heaver, but will never move as fast or faster then the bullets.

I can start with the Higgs, W and Z bosons. The photon being massless and the gluon having 8 colors, makes them a little different. Helmholtz’s second theorem for vortex dynamics in inviscid fluid states: A vortex filament cannot end in a fluid; it must extend to the boundaries of the fluid or form a closed path. Helmholtz decomposition theorem: any sufficiently smooth, rapidly decaying vector field in three dimensions can be resolved into the sum of an irrotational (curl-free, longitudinal component) vector field and a solenoidal (divergence-free, transverse component) vector field. Particles with only transverse (vertical) are members of an O(3) group and will be the same particle after being rotated or reflected in a mirror. Spinning particles with two components of spin form an SO(3) group. SO(3) group members are classified as either right-handed or left-handed using the right hand rule. The Higgs Boson is its own anti-particle, with only a transverse component of spin and a lifetime around 1.6×10‾²² seconds.. The mathematics behind a Higgs Boson decay, tells us that a 125 GeV Higgs, has a 23.3% chance of decaying into a W+/W- particle combination and a 2.9% chance of decaying into a pair of Z bosons. The W bosons have transverse and longitudinal components of spin and are unstable with a lifetime around 3 x 10‾²⁵ seconds. The Z boson has only a longitudinal component of spin. Looking closely at the model, try to visualize the decay of an unstable Higgs. The W+ and W- bosons are anti-particles to each other. If you follow the longitudinal spin of the W+ with your fingers, your thumb must point up making the W+ a right-handed particle. If you follow the longitudinal spin of the W- with your fingers, your thumb must point down making the W- a left-handed particle. The Z boson is its own anti-particle and has longitudinal spin with no transverse component of spin. It is important to note what happens when these particles interact with other matter. Both the W and Z bosons, being spin 1 particles, change the direction of spin of other particles they hit. A spin up electron (+1/2) will become a down electron (-1/2). The W bosons having a +1 or -1 charge, will change the charge of particles they hit. A +1/3 charge quark will be changed to a -2/3 charged quark if hit by a W- boson. A neat video on vortexes: https://www.youtube.com/watch?v=mHyTOcfF99o

Photons are massless packets of energy flying around at the speed of light. Yet, if you were to trap a bunch of photons in a perfectly reflective box, the box would weigh more with the photons inside then if there were no photons inside. Mass truly is trapped energy. Hermann von Helmholtz (ca. 1821–1894) was a German physician and physicist who studied fluid dynamics years ago. Specifically, Helmholtz studied vortexes in fluids and thought of particles as "vortexes of energy". Joseph Larmor (ca. 1857–1942) was a physicist who viewed matter as spinning vortexes. Larmor laid the groundwork for mathematically modelling the concepts of spin, precession and spin coupling. Coupling the up or down energy states of multiple spin 1/2 particles allows for mathematical modelling of the more complex particle spin like 3/2 or 5/2. Today is the birthday of Otto Stern (ca. 1888-1969) who performed the famous Stern-Gerlach experiment to prove the electron is a spin 1/2 particle. Swirling vortexes of energy can model each of the particles in the standard model and represent the basis of the mathematics behind modern quantum physics.

Dividing Droplets Could Explain Life’s Origin - Researchers have discovered that simple “chemically active” droplets grow to the size of cells and spontaneously divide, suggesting they might have evolved into the first living cells. A very important concept in the search for where life came from. https://www.quantamagazine.org/20170119-active-droplets-cell-division/

Not sure where to post this. This comment by Koti "Trump's youngest kid during todays inauguration looks like he's mad to be there instead of sitting at home torturing small animals." is showing up on my home page under recent status updates. The kid is only 12. If Koti has proof of this, he should report it to the authorities. I am very uncomfortable reading this type of comment about a child. Can it be removed? Edit: I see he has followed up today with "You might me right that hes not the animal torture type kid. He might be the "shoot everybody in class from an automatic weapon" type. " Very inappropriate.

Yes, spin 1 with 3 states, left-spin, right-spin and linear. Words can sometimes cause confusion - to me, polarization is the Jones Vector, but of course the position of the Jones Vector is only a probability that the orientation is really that direction. This is a useful chart to help with the relationship between visual demos, Jones Vectors and Bra-ket notation. Very well worded, +1

Just saw the new star wars movie in 3D and was wearing the glasses with spin left over one eye and spin right over the other eye. The spin (rotation of the electrical axis) is indeed caused by a phase shift. WRT explaining how photons are split, it is the same for the simple and the complex case. I tried to stick to the article's wording of the action of the BBO crystal "that the signal and idler photons emerge with the same polarization, which is orthogonal to that of the pump photon". What I find interesting here, is the "simple" case of shooting linearly polarized photons directly at the splitter does not cause the split photons to be entangled. Yet the more "complex" case of shooting linearly polarized photons first through a birefringent quartz plate to phase shift the photons (cause spin) before shooting them at the splitter results in entangled photons (as long as you throw out all the mis-matched photons).

In the article linked "Our BBO crystals are cut for Type I phase matching, which means that the signal and idler photons emerge with the same polarization, which is orthogonal to that of the pump photon." Notice they start out with a linear beam: "To create the state |ψEPRi or something close to it, we adjust the parameters which determine the laser polarization. First we adjust θl to equalize the coincidence counts N(0◦ , 0 ◦ ) and N(90◦ , 90◦ )." At this point, N(45◦ , 45◦ ) is way to low. They then cause the beam to spin so all paired input angles equalize: "Next we set φl by rotating the quartz plate about a vertical axis to maximize N(45◦ , 45◦ )." I like talking about this experiment because it has a lot of detail. If you have another specific example of how they achieve entanglement, it would be great to take a look at a few others.

First simple case: Split the photons, measure both ends at 0 and 90 degrees to make sure it works, change to 45 degrees and see what correlation you get. I mean a very straight forward vertically polarized stream of photons. When split, all should match at 0 and 90 degrees, how many match when both ends measure at 45 degrees. Are they normal pairs, or are they entangled?

I agree. Split the photons, measure both ends at 0 and 90 degrees to make sure it works, change to 45 degrees and see what correlation you get. I think the reason you do not see this simple an experiment is that they will not behave as entangled particles ie. not all will match at 45 degrees. Most experiments (ie. here) talk about creating an entangled state. In this one, they first linearly polarize the photon, then they cause the photon to spin by putting it through a birefringent quartz plate. The spinning photon hits the BBO splitter crystal in a random real polarization, splits and the two photons head off to the detectors to check for a match. I dont really see why the first simple case does not produce entanglement, but yet we are to believe that the second setup with the real experiment produced entanglement. In their words "Coincidences are detected by a fast logic circuit and recorded by a personal computer" - they are only adding up the matches so this experiment can be reproduced with classical pairing or entangled particles - ie. "wobbly photons" that are a bit random when measured off their basis vectors.

AbstractDreamer - My 2 cents. A real example of a HVT: Entangled photons, nonlocality and Bell inequalities in the undergraduate laboratory. Modelling Entangled Photons Dehlinger and Mitchell propose a model (color represents the probability of a photon getting through the filter) where each photon has a polarization angle λ. When a photon meets a polarizer set to an angle γ , it will always register as Vγ if λ is closer to γ than to γ + π/2, i.e., if |γ − λ| ≤ π/4 then vertical if |γ − λ| > 3π/4 then vertical horizontal otherwise. Refining the Model – adding Probability This models the photons as not only having a specific “average” direction, but also as having a “wobble” or “instantaneous” direction (shading represents probability of a photon getting through the filter). Represented as icons, photons present a more “fuzzy” picture of their polarization. The sample 24° photon, with a 30° wobble, will most of the time be picked up as a vertical, but sometimes when the combined angle is over 45°, it will be picked up as a horizontal. To determine polarity, we use these equations. Chance of vertical measurement = (cos((γ − λ)*2)+1)/2 Chance of horizontal measurement = (cos((γ − λ + π/2)*2)+1)/2 I believe this will indeed produce the proper numbers BUT carries a new problem. You will get what looks like a lot of noise when you measure at 45 degrees, since many of the split photons will not measure the same polarity because of the randomness. I suspect there is an experiment somewhere that would "close this loophole"?

I would like to see your drawings, they would be illuminating. Where the fun come in, is to get a good model of the photon and then start to send groups of them around to see if you can model the actual properties seen. The "plane wave" model of the photon produces a pretty good Michelson Interferometer

Yes I am showing an expanding and contracting circular plane wave. Notice how when the E is positive, the plane wave is a very light color. When E is negative the plane wave is darker. This allows multiple photons to reinforce each other if they are in phase (dark with dark makes darker, light with light makes lighter), or to cancel each other out (light with dark makes a background grey) and gets me the full up/down cycle. Put another way, the size of the circle and the color of the circle match the amplitude of E and the orientation of E respectively. An animation of photon reinforcement and cancellation here.

X-direction, forward in the motion of the photon.

Not sure I read this right, but certainly if the polarization was circular, you would want to see the quadrant rotate. This photon is vertically polarized.

This post is an extension of an earlier post meant to focus specifically on a photons "self energy" and how it moves through space. Specifically consider Landau & Lifshitz Vol. II. On page 108, the wave equation section talks about electromagnetic waves “in which the field depends only on one coordinate, say x (and on the time). Such waves are said to be plane”. Electromagnetic waves are ever changing “plane waves moving in the positive direction along the X axis”. In volume IV, page 5, Landau & Lifshitz continue, talking about Quantization of the Free Electromagnetic Field and on page 11, introducing photons: These formulae enable us to introduce the concept of radiation quanta or photons, which is fundamental throughout quantum electrodynamics. We may regard the free electromagnetic field as an ensemble of particles each with energy ω (= ħω) and momentum k (=nħω/c). The relationship between the photon energy and momentum is as it should be in relativistic mechanics for particles having zero rest-mass and moving with the velocity of light. … The polarization of the photon is analogous to the spin of other particles; …. It is easily seen that the whole of the mathematical formalism developed in §2 is fully in accordance with the representation of the electromagnetic field as an ensemble of photons; it is just the second quantization formalism, applied to the system of photons. … A photon is a plane wave travelling through space at the speed of light.

Relativity calculations are done by professionals using ADM equations or a thing called BSSN, unfortunately, above my payscale. For details, there is a good video here. This post is about speculations. To make the point with a more mathematically-based model of gravity using exchange particles, consider an animation with grid spacing of 10 kilometers and time intervals of about 9 hours. Between each frame, the forces on all objects (Sun and Earth in this case) are calculated using Newtons inverse square law. The force is added to the motion of the the object, the motion of the object is added to the location of the object and the scene is re-displayed. If you stop and step the animation at the right time, you can see that it calculates a pretty accurate orbit time (just over 365 days and 6 hours) and gets the aphelion and perihelion pretty close. http://www.animatedphysics.com/planets/Earth_Orbit_v1.htm To have a look at precession, we need an orbit that is not circular. Using different momentum for the earth at the start of the animation produces a very eliptical orbit for the earth, but no matter the starting positions or momentum of the Sun and the Earth, we always end up with an elliptical orbit that does not precess. http://www.animatedphysics.com/planets/Earth_Orbit_v2.htm To calculate force under Newton, we use F = G0*Mass/R^2, where G0 is the gravitational constant and R is the distance between them. To add the force of the exchange particle being sucked out of the planet, assume force is related to the inverse of R, ie. F = G0*Mass/R^2 + G1*Mass/R. Right away we see that we get precession and the amount of precession depends on G1. Ie. we can reverse engineer the orbit of Mercury by using the right value of G1 that produces the proper amount of precession. http://www.animatedphysics.com/planets/Earth_Orbit_v3.htm No one is saying that adding G1*Mass/R to the force is correct, only that adding the exchange force can produce precessing orbits and infact can produce "butterfly" type orbits posted above if you aim the earth in close enough to the sun. If you could produce an equation for the correct exchange force there are a couple of pretty interesting implications: 1/ Black holes would no longer be black holes. As objects with mass fall in closer to the event horizon, more and more mass would be sucked out in the form of gravitons and you would end up with a ball of energy (ie. gravitons) from which nothing, including light could escape. No need for wormholes or alternate universes to explain what is going on. 2/ Gravity would look very different on a large scale as in the orbits of entire galaxies. The force on stars close to the center of the galaxy would not change that much, but the force on stars on the outer edge of the galaxy would be greater then under the inverse square law and they would rotate faster then you would expect (maybe like this?). No need for dark matter to explain the orbit of galaxies.

Nothing new here, if you want a list of things I am wrong about, just ask my wife.

Sure tops precess, no argument there. You can also make an orbit precess by adding in a third planet or by deforming or spinning one of the masses. The math you quoted is under the section starting with "However, in actual physical situations, the gravitating body may not be exactly spherical." There was a great historical effort to account for Mercurys precession by other planets farther out, maybe a planet on the other side of the sun we cannot see, maybe a distortion in the internal mass of the Sun, maybe the spinning of the Sun or maybe a tiny planet in close to the sun. All of these effects were calculated and failed to account for Mercury's precession and Einstein's version of gravity won out. The early part of the linked article goes through all of these efforts: It is a definite fact that a 2-body system will form a non-precessing ellipse under Newtonian gravity. Certainly other things can cause precession. The crowning achievement of Einstein's equations was to account for this precession.

Thanks for the comment. "Speed of energy" is short for "speed of massless particles" like gravitons and photons, assumed to be the speed of light. Newtonian physics does NOT deal with precession. Using Newtons force laws on 2 bodies that are rotating around each other like the Sun and Mercury will ALWAYS produce an ellipse that does NOT precess. You cannot produce a precessing orbit with Newtons laws. Also, although I agree the precession on Mercury is very small, the discovery that it did precess was a very important historical observation that led to doubt about Newtons gravity. For large masses that are much closer then Mercury and the Sun, precession becomes the dominent feature of their orbit. You can see some dramatic examples at mathpages.com and the history and mathmatical derivation of their orbits here. Both of these orbits would be non-rotating ellipses if Newton's laws were used. I agree with you comment on GR, but, every force has its field, including the gravitational force. The graviton is simply the quanta of that field. We are simply quantizing this gravitational field, and everything which is quantized has its quanta, which in this case is the graviton. The only thing different when someone talks about the graviton is that the G force is not smooth, but rather comes in discrete lumps. Also, no one has ever "seen" the graviton, so we can't say with certainty that it even exists. Hence I posted in the "speculations" section of your forum. Finally, the "repulsion" animation works for "quanta of energy" like a photon hitting something, but the "speculation" is using the "attraction" animation to model gravity and the graviton. Best wishes.

I am new here, so hopefully this is an appropriate post for the speculations section. This is about the first principles of gravity and the differences between Newton's version and Einstein's version. When looking at the effects of the two versions, the differences are obvious. Newton used the inverse square law where the force you feel from another mass is inversely proportional to the square of the distance you are from it. Go twice as far away and you feel 1/4 the force. When modelling planetary orbits, you always end up with an elliptical orbit that never precesses. Unfortunately for his theory, the orbit of Mercury precesses. Newton was wrong. Einstein's is quite different. You have precessing orbits, gravitons and curved space (among other things). What are the differences in the fundamental assumptions that make the two different? After doing some research, consider the following: Newton: A note from Newton's Principles definition #4 in 1687: Impressed Force - This force conflicts in the action only; and remains no longer in the body when the action is over. Einstein: In Einstein's second paper on relativity in 1905, he explicitly concludes: "Radiation carries inertia between emitting and absorbing bodies". It is important that not only does something receive a "kick" from the momentum of the energy, but the internal inertia (i.e., the inertial mass) of the body is actually increased. Newton's base assumptions clearly conflict with Einstein. To model Einstein, start with a model of repulsion. Say we take a machine gun and shoot it a lump of lead. The bullets hit the lead and get stuck inside. They provide both a kick to the lead to make it move a little faster as well as they increase the mass of the lead ball by sticking inside it. The illustration demonstates this and you immediately see that the blob of lead will never go quite as fast as the bullets no matter how many you shoot at it. The first few bullets speed the lead blob up quite a bit, but as it gets heavier and faster, the bullets have less effect. You can get the blob of lead going to 99% of the speed of the bullets or even 99.9999% of the speed of the bullets, but the blob will never go as fast as the bullets. Now let's reverse this to model attraction. Instead of shooting bullets at the lump of lead, we suck the bullets out. Sucking out the bullets speeds up the lump of lead but again we see that the lump of lead cannot get to the speed of the bullets as it will always be slower then the bullets that are being sucked out. In addtion, the lump of lead will eventually simply disappear as all the bullets get sucked out of it. Finally, if we assume the bullets are gravitons travelling at the speed of light and the lump of lead is our normal view of "mass" we get Einstein's gravity with all the wierd things associated with it. Comments?

The equation Swansont posted tells the correct story. To relate photons to "usual" or "classical" mass you need some way to "weigh" them. Ie. you put them on a scale, or you see how much resistence they put up when they are thrown. This is hard to do, but if you trap a bunch of photons in a box that perfectly reflects the photons and keeps them inside, then throw the box full of photons, you would find that the box full of photons is harder to throw then the empty box, as if the photons had "classical" mass. If you put the box full of photons on a scale in a gravitational field, it would "weigh" more then the empty box.

This may help: http://www.perimeterinstitute.ca/videos/david-wineland-keeping-better-time-era-optical-atomic-clocks The video of nobel prize winner David Wineland talking about the different speed of clocks in different gravitational potentials helps with "real life" understanding of Einstein's Special Theory of Relativity where time passes slowly for an observer when the observer is near a gravitational source. I found it very valuable and informative to watch.