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  1. J

    KSTAR recent result and breakeven

    I assume this result was from a run with ordinary hydrogen, no deuterium or tritium. But I think the equivalent DT values are frequently calculated. Is this possible here? TIA again
  2. J

    B What is going on at LIGO/VIRGO?

    Why no new data? No news of any problems that I have heard. I'm both mystified and concerned. Jim Graber
  3. J

    Chernobyl Interesting new paper on Chernobyl According to this paper, two nuclear explosions and one steam explosion took place.
  4. J

    A Tension between recent dark matter results and Lux-Xenon?

    How much tension between recent AMS-02 80 Gev dark matter and Lux-Xenon negative results? Recent results ( Arxiv 1610.03840 and 1704.08258) suggest a WIMP dark matter particle near 80 Gev. See also If this particle really...
  5. J

    Tokamak News and Queries It appears that Stuart Prager is “stepping down” as director of PPPL. I wish him well. But in the announcement it refers to a “recent technical setback in the NSTX-U facility”. I had not heard previously of this set...
  6. J

    A Shocker: PR Box is logically inconsistent

    If correct, Uzan refutes Popescu and Rohrlich. To me this seems like a big deal. Super-Quantum, Non-Signaling Correlations Cannot Exist Pierre Uzan Comments?
  7. J

    Electrons, Muons and Pauli Exclusion

    Lepton Universality and Pauli Exclusion Put in a possibly oversimplified way, lepton universality says that electrons, muons, and taus all behave in the same way except for mass effects. The question is “Does this apply to Pauli exclusion?” Due to the Pauli exclusion principle, only two...
  8. J

    Smallest possible spinning clock?

    The earth's rotation acts as a clock and defines a rather precise unit of time called the day. We could go out in outer space and spin a marble and get a reasonable clock. On the other hand, it is my understanding that you can't do this with an electron, that is, you can't start an electron...
  9. J

    What all has intrinsic spin?

    What does and does not have intrinsic spin? Wikipedia Spin (Physics) [Broken]) says: “In quantummechanicsand particlephysics, spinis an intrinsic form of angularmomentumcarried by elementaryparticles, composite particles (hadrons), and...
  10. J

    Alternate fuel for TriAlpha Fusion Reactor Design? Above is a link to a news story about the recent Tri Alpha Energy “breakthrough”. It looks to me like a very nice development in increased stability of a proposed reactor design. Tri Alpha...
  11. J

    Does a Buckyball spin like an electron or like a baseball?

    Does a Buckyball spin like an electron or like a baseball? We are often told that an electron does not really spin like a baseball. Only one (or two, if you count up and down) spin states, for example. How about a Buckyball? Does it spin more like an electron, or more like a baseball? Where...
  12. J

    Collapses, Quantum Jumps, and the Born interpretation

    In my mind they are all the same. But some serious physicists (Schlosshauer, for example) claim there is no evidence for the existence of collapse. What about Lyman alpha emission, where an electron in a hydrogen atom “jumps” from level two to level one and emits a photon? Or the...
  13. J

    Which photons pass through a circular annulus?

    Passing light through a circular sieve: Well, actually, let’s think about radar or microwaves with a wavelength of order a centimeter or two, so you can tailor your aperture, say by etching a silver screen on glass. If you have a reflective metal screen, and you cut a long narrow rectangle in...
  14. J

    Four random quasars in a straight line? National Geographic quoting Dr Hennawi, the lead author of the Science paper, says it is a ten million to one chance to find four quasars so close together. How much more unusual is it that in the first...
  15. J

    Lockheed SkunkWorks Fusion plan

    In the news today, several articles about Lockheed's ambitious five or ten year plan. eg this one from the Washington Post. This one from Aviation Week...
  16. J

    India's thorium reactor delayed

    India's thorium reactor delayed. So another year delay, more or less. Will it really start up next year? I hope so. Jim Graber
  17. J

    How many gravitons are there in the observable universe?

    It is thought that there are approximately 10^80 protons in the observable universe, but there are approximately 10^90 photons in the observable universe. If my googling is correct, there are also approximately 10^90 neutrinos in the observable universe, but their temperature is only 1.9 degrees...
  18. J

    Fire Wallow disfavors Event Horizons

    In the context of the recent Fuzz or Fire workshop, I would like to make a short argument that event horizons are irredeemably in conflict with unitarity: An argument frequently mentioned in the Fuzz or Fire workshop is that by the...
  19. J

    Formula for transverse decrease in signal strength?

    Alice is transmitting an electromagnetic beam to Bob. Assume it is a well collimated beam, like a laser beam, or a maser beam. As Bob's distance from Alice increases, his signal strength decreases according to the well known inverse square law. Eve, the eavesdropper, is beside the beam, not...
  20. J

    What does a deBroglie wave look like?

    Are deBroglie waves transverse or longitudinal? Can they be polarized? What about the deBroglie wave of a ground state neutral spin-zero Helium 4 atom? What experimental evidence do we have that supports the detailed nature of a deBroglie wave? I have always assumed that deBroglie waves...
  21. J

    Splitting a light beam into opposite circular polarizations?

    Is it possible to split a single light beam into two beams of opposite circular polarization? A properly oriented calcite crystal will separate a unpolarized beam into two beams, one vertically polarized and one horizontally polarized. Other polarizers pass just one polarization and absorb...
  22. J

    Combining light beams question

    When you combine two light beams with a half-silvered mirror, do you get a mixture or a superposition?
  23. J

    How do particle scattering cross sections scale with energy in colliders?

    How do particle scattering cross sections scale with energy in colliders? Particularly photons, electrons, protons, and gold or lead nucleii? (If necessary, break this into four separate questions.) It is stated that due to the Heisenberg uncertainty principle, it takes more energy to...
  24. J

    Information erasure without an energy cost

    Pay with angular momentum instead of energy? What do the experts here think of this recent paper? In particular can you really change the spin or angular momentum without changing the energy? Would this also apply to ordinary momentum? (Note the authors say...
  25. J

    Two qubits out of how many?

    Recently the NIST group demonstrated a two qubit programmable quantum computer, And another consortium used a two qubit computer in an iterative fashion to compute some properties of the hydrogen molecule. How many qubits...
  26. J

    Quantum spreading of polarization

    After we measure the position of a particle fairly sharply, it “spreads out” or the uncertainty grows according to the Heisenberg uncertainty principle. After we measure the polarization of a photon, does it spread out, too? If not, why not? If so, how fast? TIA Jim Graber
  27. J

    Retrocausality solves QM problems?

    Retrocausality solves QM problems?? Does retrocausality successfully solve the problems of QM? This recent paper seems to claim it does. Comments, anyone? Also what is the relationship of retrocausality and collapse? TIA Jim Graber
  28. J

    Polarizing radar waves with egg slicers

    If I bought a radar gun, a radar detector, and three egg slicers, should I be able to demonstrate the three polarizer crossed polarization tricks? TIA, Jim Graber
  29. J

    If no singularity, what’s inside a big black hole?

    Both string theory and loop quantum gravity claim possible elimination of the black hole singularities. If that is true, what do they predict the inside of a stellar size black hole contains? Is it some new ultra dense state of matter, or something else? I will try to ask various...
  30. J

    Why don’t planet hunters find black holes?

    Over 200 planets have been discovered by the radial velocity technique. Why no black holes? For similar periods, the signal amplitude should be much greater. TIA. Best, Jim Graber