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Can space-time be quantized?

  1. Jun 20, 2005 #1
    I only dabble in physics, so a layman's explanation would be appreciated. My question is, can space-time be quantized? I know that Plank's constant is often used for both length and time, so does it apply also to space-time?

    I ask this question because it appears to me that this concept can go a long way in explaining many phenomenon in physics. For example, the fact that light energy is quantized (photon) would be identical to saying that only a constant amount of energy can occupy a quantum of space-time. Furthermore, Doppler Effect (spectrum shift) can be seen as shift in amount of quantized space-time encountered as the source/observer moves through space-time.

    If one were to add another concept to this, things get even more interesting. Assume for a minute that the expansion of the Universe and the Dark Energy both point to inflation of quantized space-time. I suggest this inflation be somewhat similar to cell-division that results in overall growth (or inflation) of space-time. If this were true and it happens at the speed of light ("c"), then we can easily infer that a photon is actually "carried" by the process of space-time inflation. I realize that this concept sounds like an "ether" model, but no one can deny that "ether" exists in the form of space-time quanta, not as a directly observable material entity.

    Although I have no basis for the correctness of this model, but consider the following interesting implications if this model were to be true:

    Wave/Particle Duality – This concept intrigued many scientists. I’ve read somewhere that not only light/photon, but also electron and other fundamental particles, behave in wave/particle duality mode. If space-time quanta exist, then the very fact that it can be quantized can lead to Particle-like behavior for energy that is concentrated in them (matter in general, but more pronounced in discrete quantity). If you also consider the inflation of space-time (whether by cell-like division or by some other means), then you can immediately see the Wave-like behavior. What’s more, the inflation of space-time can lead to probabilistic behavior inherent to QM if one were to assume some sort of interaction among dividing or inflating space-time quanta. Can this explain the Double-Slit experiment?

    Time and Gravity – Can time be thought of in reference to space-time quanta? Since Einstein proved that time is relative to each observer, can we assume that time travels out in all directions at the speed of light ("past"), with new "future" arising at every point of space-time quanta? If so, then this would certainly fit in nicely with time-dilation caused by high-velocity (acceleration) and objects within a gravitational field. For example, if object A is accelerating away from object B, then object B will be "catching up" with the expanding "past" as observed by object A, thus aging slowly. This concept applies to both acceleration and deceleration since what matters is only the change in velocity in relation to the observer (because the inflation/passage of time arises from all points of space-time quanta). Thus, it can be said that Gravity (and the effects felt from Acceleration and Deceleration) is the result of potential difference in amount of space-time inflation at a quantum level. Matter can be thought of as a region in space-time where this inflation (or division) is inhibited (thus the condensation of energy rather than light/photon that is carried off by the inflating space-time), which in result creates a potential difference in space-time quanta that is culminates into Gravity. Since Acceleration and Deceleration changes the potential of space-time quanta, it results in same net effect as that of Gravity.

    If all this thought-experiment were to be true, then even Black-Hole can be thought of in different ways. It can be simply stated that a Black-Hole is a region in space-time where matter (by above definition) occupies all the space-time quanta so that no expansion occurs within the region defined by the Event Horizon. I wonder if someone can calculate this hypothesis since I lack the advanced math to do it myself.

    Please note that all this is just for fun arising out of my thought-experiments based on little that I know. If anyone can add anything interesting in relation to this model or can shed light on where I went wrong, I would appreciate it very much.
  2. jcsd
  3. Jun 20, 2005 #2


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    The question you raised is under discussion in the physics community, in particular when it comes to uniting general relativity (a "classical" theory) and quantum theory. One approach goes by the name loop quantum gravity.
  4. Jun 20, 2005 #3

    Thanks for pointing me in right direction with Loop Quantum Gravity. I googled and found a site with lots of information on this subject, but they were way too technical for me to grasp. However, I think the general concepts were similar to what I attempted to outline, so I'm glad I wasn't too much off base.
  5. Jul 4, 2005 #4
    “The absolute space, the absolute time and the geometry itself, is not a condition forced upon the mechanics.” Henri Poincaré, 1902

    Do we really make an adequate distinction between geometrical models of space and an eventually existing physical space? Is "common sence space" anything but an idea of human mind?

    In quantum mechanics the principle of correspondence is the interface between efficient mechanics and geometrical ideas appealing to our minds. The mindboggling Lorentz transformations could be thought of as a correspondence principle between high energy mechanics and euclidian space.

    Developement in physics will separate all physical theories from the primitive ideas apealing to our psyche. Quantum cosmology is coming, but common sence is in love with the straigth line and retard the process.
    Last edited: Jul 4, 2005
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