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  1. C

    B Matter - antimatter asymmetry

    What does quantum mechanics have to say about this aspect? Matter usually differs by antimatter having opposite charge. It is said that the Universe in the early stages should have created equal amounts of matter and antimatter. The total charge is conserved no matter the interactions and if...
  2. C

    B Gravitational wave's velocity

    In flat Minkowski spacetime, everything that travels at c, relative to some observer, it travels the same speed relative to any observer. If we refer to gravitons as bosons through this flat spacetime, it is clear they can be defined as travelling at c. And you can even some classical...
  3. C

    B Double slit experiment ratios

    Here is a setup that only uses fixed detectors. Will the ratio between the number of detections at D0 and the sum of the numbers detected on D1 and D2 be close to 1? For this question instead of the coincidence counter, 3 simple counters are needed. Also the detectors D1 and D2 need some lenses...
  4. C

    B Particle pair creation probability

    I know that a high frequency light beam is more likely to generate a virtual electron-positron pair than a low frequency one. Can this probability depend on the reference frame? It seems there is a paradox. How do we explain it?
  5. C

    B Magnetic moment of electrons

    If electrons have a magnetic moment (or behave like they have) why don't all orient North Up in a magnetic field (pointing down)? Plus, if thought as magnetic dipoles, like poles repel, therefore all should point the same direction. In a Stern-Gerlach apparattus shouldn't the magnetic moment...
  6. C

    I Stern-Gerlach using magnets

    Is there any study involving real magnets behaviour shot through Stern-Gerlach gates? I've seen something using rather large magnets[1], but still the pattern showed two bulges. I if suppose using very small magnets the split-up would be much clearer. After all these magnets are not simply...
  7. C

    I Quantum entanglement information

    It is said that the measurement done on a particle instantly affects its entangled pair because Bell's theorem excludes a hidden variable. That means there is a cause and an instant effect at a distance. Say we have two entangled particles A and B. If there is no hidden variable then the state...
  8. C

    I If electromagnetic waves propagate, do photons as well?

    In classical physics, EM waves propagate this is one of the main features of all waves in general. Usually for mechanical waves the elements (like molecules) that vibrate do some little motion. For example a string can move up and down, but the waves travel further through propagation. The...
  9. C

    I Can we apply relativistic field transformations to electromagnetic waves?

    If we move towards a source of EM waves, in our reference frame the frequency appears (and it is) higher than what a stationary observer will see due to Doppler effect. The field transformations show that these two observers will se static fields differently so I would also expect that the peak...
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    I How do we interpret an EM wave using Quantum Mechanics?

    I know that if the intensity of a light beam with of a certain frequency varies it means the number of photons the light beam is composed of varies and not the individual photons energy. That would mean the E and B field amplitudes vary. This would mean that that the amplitudes of the E and B...
  11. C

    I Fundamental elements transformation

    I wonder if it is possible to express a simple principle into a mathematical form. The simple principle says if at time t0 an isolated system is composed of some elements with some properties then at t1 it is composed of other elements with different properties, then in principle it is possible...
  12. C

    How much energy is required to accelerate a charge?

    Lets suppose we have a charge and we want to accelerate it from a point A to B and back. Does the energy requirement increases if we move the charge quicker? I can make an analogy with mass. To accelerate an object over a distance d requires energy. The objects resist to change in velocity. The...
  13. C

    I Relativistic velocity scenario

    Lets suppose there is an observer at a certain distance from a planet that is moving at 0.9c as seen by the observer. We take as a reference, a frame where the observer is at rest. A spaceship leaves the planet and begins accelerating relative to the planet in the oposite direction. The observer...
  14. C

    I What is (rest) mass for a particle?

    The energy equation for a particle contains the rest mass and momentum. If the momentum is zero, all the energy comes from the term mc^{2}. That means the particle still holds some energy. What is the form of that energy? For example string theory explains particles as vibrating strings, and I...
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    I Measurement precision question

    Supposing we have 2 circles in a 2 d space that can bounce off each other like balls. These circles are made of an infinite number of points. We put the centre of each circle on a line and send them towards each other along the line. Are they going to bounce off keeping their trajectory on the...
  16. C

    I Permittivity/permeability variation in time

    Is it possible to tell with certainty whether μ and ε for vacuum change over time within a very long period of time? I know that we are measuring a space expansion, and we can tell that not objects are moving away from each other, but the space itself expands. However, this seems to be similar...
  17. C

    Orbital angular momentum wavefront velocity

    Is the wavefront velocity if an OAM mode 1 light beam proportional to its wavelength? I understand that the helical structure step length gives the wavelength of the beam. In this case, a small wavelength beam would travel much slower. The problem is, f=v/λ, but now v<c and if λ is shorter then...
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    I Do photons that carry orbital angular momentum have mass?

    It is known that particles with rest mass cannot travel at the speed of light. Can we also say that particles that travel at subliminal velocity, like these OAM photons do, have mass? It has been demonstrated [1] that these beams can be thought as made of photons that posses intrinsic OAM, and...
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    I Photons under gravity

    Why does the energy of a photon increase when falling into a gravitational field ? If we use the equation E=hf, then the energy of the photon increases, but I understand that we also need to add the potential energy to find the total energy. Et=Ep+hf. The potential energy decreases by the same...
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    B Standard model particle properties

    In the Standard Model, for any particle, I have only found properties related to electromagnetic and gravitational (in fact mass does not necessarily mean it is a property related to gravity, but to emergy)forces like charge and mass. Why there isn't anything about the other two interactions...
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    B Has anyone tested a polarization filter sending through photon by photon?

    To properly test a filter, I understand we can use a source of vertically polarized light. We send photon by photon say 1000 though a filter at, for example, 45 degrees the count the ones on the other side. We should get roughly 500, depending of the quality of the setup. I was interested in a...
  22. C

    B Gravity between light beams

    In the experiment using pencils of light by Tolman, is has been shown that two parallel light beams do not attract but anti parallel beams do. What happens if we use different wavelengths for the light beams. Will the higher frequency beam be less deflected ?
  23. C

    B Does gravity change the permittivity/ permeability of vacuum?

    For example if you send a light beam towards a massive object the propagation speed will reduce if μ and ε are increasing, but the spacetime curvature will compensate for that reduction.
  24. C

    I What happens to an OAM light beam, with helical mode m>1, when accelerating under gravity?

    It is known that wavefronts of internal OAM photons travel slower than light but I wonder what happens if you accelerate such a beam. This should be possible under gravity.
  25. C

    Is the electromagnetic propagation time asymmetrical?

    For a point in space if we have the values of E and H fields at a certain instant of time, we can tell the direction of the propagation of these values, which is the direction of the cross product vector E x H. Is this phenomenon time asymmetric or not ?
  26. C

    B General relativity vs. Newtonian gravity

    I understand that General Relativity can make a difference between a spinning and non spinning mass thus can make better prediction for planetary orbits for example. The effect is frame dragging. However if we simulate a newtonian gravitation and instead of representing a planet as a sphere...
  27. C

    I How does time work?

    Let's consider freezing time and plotting all the information in a 3d space, with an imaginary (not related to complex numbers) fixed metric. For this we need a reference frame. In this coordinate system we will have all the information about the universe. Then we go plot the next snapshot of...
  28. C

    I Who is moving faster?

    Suppose we have a single planet in the entire universe and we send a probe through space. There is a clock on the probe and one on the planet. The probe will fly at a constant speed relative to the planet then it comes back. We will ignore the acceleration period. Which clock will show a lower...
  29. C

    B Photon dimensions

    I know photon is considered a point particle, so it means it has no physical dimensions, if I'm not wrong. Plus, it has a probability wave function associated to it. It also interacts as a wave which consists of an electrical and magnetic field perpendicular to each other and delayed by a...
  30. C

    B Classical EM wave

    There is also a classical model of a photon available, which to me explains a particular behavior of it. Can this model be proved to wrong ?