Negative Energy/Negative Matter

  1. I just learned recently about the possible existance of negative matter and negative energy and I would just like to have this confirmed: In theory, interactions between negative matter and positive matter have opposite effects in comparison to those between positive matter and positive matter...is that right?
     
  2. jcsd
  3. Chronos

    Chronos 9,928
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    Depends on what you mean by 'negative matter'. Anti-matter behaves just like ordinary matter until the two cross paths. Negative matter, as in matter with repulsive gravity, has never been observed, nor has it any meaningful theoretical support.
     
  4. oh...I read that there was some thin experimental support for negative energy, but not so much for negative matter...but what do you mean by theoretical support?
     
  5. ZapperZ

    ZapperZ 29,823
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    Please cite your sources. Where did you "learned" this from? Without proper citation (which is something we strongly recommend or require whenever someone writes that he she has heard/read/learned/etc something from somewhere), it is difficult to know if you understood what you learned correctly.

    Zz.
     
  6. Are you referring to dark matter and dark energy at all?
     
  7. It was read as negative matter and negative energy. I was reading on the Thorne Time Machine and it became relevant.
     
  8. Well, the only real way to get negative energy is by going below absolute zero (impossible).
     
  9. http://www.phy.duke.edu/~hsg/55/related-files/sciam-wormholes-jan-2000.pdf
     
  10. As far as I can tell, the terms 'negative matter' or 'exotic matter' only exist because Kip Thorne and the like want to believe in wormholes; more specifically, wormhole-induced time travel.
     
  11. LURCH

    LURCH 2,512
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    On the contrary; negative energy is an accepted concept in QM. Take any light-wave with troughs of near-zero energy. In a squeezed state, the peaks get taller, and the troughs can go below zero. I read about this in SciAm quite a few years ago. In fact, I think it was right around the turn of the millennium. I will look through my back issues and try to locate the article.*

    Negative matter, OTOH, appears to be precluded by the rules that govern negative energy. Specifiaclly, for any system to possess negative energy requires that that same system possess a greater amount of positive (or normal) energy. So, for a lump of matter to be constructed exclusively from the negative energy would appear to be impossible.

    * Yup; it was, in fact, the January 2000 issue. The article "Negative Energy, Wormholes, and Warpdrive"; Lawrence H. Ford and Thomas A. Roman.
     
    Last edited: Dec 18, 2008
  12. ZapperZ

    ZapperZ 29,823
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  13. Correct me if I am wrong: but as i had learned, any attractive force field ( gravity field, opposite sign electric field ) has negative energy : -km/d

    for negative matter: negativity must be defined:

    if you are talking about electromagnetic force, negative matter of electron would be positron which are completely same despite their charge.

    if you are talking about gravitational force, negative matter would be an electron with negative mass -> never observed. remember mass means source of gravitational force, but it also means the response of a particle to an applied force. F=ma
    if a particle would have negative mass, it would move towards the force if a force is applied to it, it wouldn't move towards where the force is applied to.

    there also are 2 different force types: strong and weak force, so "strong charge" also exists. in that manner, negative matter would mean that particle with opposite "strong charge" and when you study quarks, you can see that quarks with opposite "strong charge" are long time known and already observed years ago.
     
  14. Im curious about this too.

    Is anti/dark/negative matter the definition of the same thing but with just different labelling?

    e2a: Negative energy/matter is just dark energy/matter

    iGeddit
     
    Last edited: Feb 4, 2010
  15. The concept of negative energy and antiparticles came up in Dirac's model for the electron wave function in the 1920's, and are diiscussed in his book "The Principles of Quantum Mechanics", published in 1930, about 3 years before the first antiparticle, the positron, was discovered. The discovery of the positron satisfied Dirac's predictions that the electron should have an antiparticle. In the fourth edition of his QM book, Dirac discusses "the electrons falling into unoccupied states of negative energy. In this case we should have an electron and positron disappearing simultaneously, their energy being emitted in the form of radiation." [The annihilation radiation we know now is equal to twice the rest mass of the electron.]
    Dirac continues ""from the symmetry between occupied and unoccupied fermion states, .... the present theory is essentially symmetrical between electrons and positrons. We should have an equivalent theory if we supposed the positrons to be the basic particles, .... and then supposed that nearly all the states of negative energy are filled up..... with electrons."

    So instead of negative energy matter, we might instead have somewhere........ galaxies of antimatter.

    Bob S
     
  16. Ex: pro matter hydrogen: 1 positive proton and 1 negative electron
    Anti matter hydrogen: has one negitive proton and one positive electron
    This is somehow possible in the theory i heard
     
  17. It's not only theory, but experiment. Dirac predicted antimatter in 1928. CERN has made anti-hydrogen atoms at LEAR (Low Energy Antiproton Ring) for over 10 years. See

    http://livefromcern.web.cern.ch/livefromcern/antimatter/.

    Bob S
     
  18. The OP is definitely talking about potential quantum effects of the type expect in the ergoregion of a Black Hole, or event horizon. In THEORY in QM there could be regions of negative energy density, but as an earlier poster said this is mostly Kip Thorne wanting a way to keep open ERBs.

    The idea, completely without evidence, but with some math behind it, is that the "throat" of an ERB could be prevented from closing instantly by using energy or matter with a REPULSIVE force in relation to normal matter. This "Negative Matter/Energy" would counterbalance the attractive force that would normally turn you into whatever baby singularities are made of. :rofl:

    As far as I know it is more of a local effect or imbalance as a result of GR/QM than a real thing you could make in an accelerator.

    From Wikipedia: "Negative mass in general relativity
    In general relativity, negative mass is generalized to refer to any region of space in which for some observers the mass density is measured to be negative. This can occur due to negative mass, or could be a region of space in which the stress component of the Einstein stress-energy tensor is larger in magnitude than the mass density. All of these are violations of one or another variant of the positive energy condition of Einstein's general theory of relativity; however, the positive energy condition is not a required condition for the mathematical consistency of the theory. (Various versions of the positive energy condition, weak energy condition, dominant energy condition, etc., are discussed in mathematical detail by Visser[3].)

    Morris, Thorne and Yurtsever[4] pointed out that the quantum mechanics of the Casimir effect can be used to produce a locally mass-negative region of space-time. In this article, and subsequent work by others, they showed that negative matter could be used to stabilize a wormhole. Cramer et al. argue that such wormholes might have been created in the early universe, stabilized by negative-mass loops of cosmic string[5]. Stephen Hawking has proved that negative energy is a necessary condition for the creation of a closed timelike curve by manipulation of gravitational fields within a finite region of space;[6] this proves, for example, that a finite Tipler cylinder cannot be used as a time machine."


    The Dirac Vaccuum explanation has already been provided by Bob S.
    For the record, I don't know much about this beyond its utility in sci-fi.
     
  19. If you would like to learn more about Negative Energy, (which was originally proposed in the 1930s by Dirac), you may want to check out the Wikipedia article on the Dirac Sea.
     
  20. Vanadium 50

    Vanadium 50 17,527
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    It seems kind of pointless to continue to speculate on what the OP means, especially since he is here and can comment on his own.
     
  21. I realize that the OP has not been a part of this thread for a while. I simply wanted to put a useful endcap on the discussion which others may find useful.
     
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