Can space-time be quantized?

[Physics101]

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.

[mathman]

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.

[Physics101]

mathman,

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.

[bigles]

“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.

[mcgucken]

Moving Dimension Theory

Hello Physics 101!!

Moving Dimensions Theory quantizes space-time, and it adds the one key component that the time dimension is expanding at a rate of c relative to the three spatial dimensions, in increments of the Planck length.

This unifies Quantum Mechanics and Relativity while explaining many physical phenomena such as the EPR effect, double slit experiment, action-at-a-distance, the red shift, time dilation, length contraction, and more.

For more info, look here:

http://groups-beta.google.com/groups?hl=en&lr=&safe=off&q=moving+dimensions&safe=off&qt_s=Search
http://www.google.com/search?hl=en&lr=&safe=off&q=moving+dimensions+theory&btnG=Search

and at the home port:

http://physicsmathforums.com

On September 1st, 2002, I sent it to several leading physicisists, but alas, they didn't have time to respond, as they were busy raising millions of dollars for the postmodern hoax that is called string theory.

But as of late, they've been coming to me...

Expect the book in the fall.

[mcgucken]

The Dimensions Are Indeed Moving!!!

LEE SMOLIN says so!!!

LEE SMOLIN a theoretical physicist, is concerned with quantum gravity, "the name we give to the theory that unifies all the physics now under construction." More specifically, he is a co-inventor of an approach called loop quantum gravity. In 2001, he became a founding member and research physicist of the Perimeter Institute for Theoretical Physics, in Waterloo, Ontario. Smolin is the author of The Life of The Cosmos and Three Roads to Quantum Gravity.

http://www.edge.org/3rd_culture/smolin03/smolin03_p5.html

Another reason that string theory cannot be the final word is that in string theory one studies strings moving in a fixed classical spacetime. Thus, string theory is what we call a background-dependent approach. It means that one defines the strings as moving in a fixed space and time. This may be a useful approximation, but it cannot be the fundamental theory. One of the fundamental discoveries of Einstein is that there is no fixed background. The very geometry of space and time is a dynamical system that evolves in time. The experimental observations that energy leaks from binary pulsars in the form of gravitational waves—at the rate predicted by general relativity to the unprecedented accuracy of eleven decimal places—tells us that there is no more a fixed background of spacetime geometry than there are fixed crystal spheres holding the planets up. The fundamental theory must unify quantum theory with a completely dynamical description of space and time. It must be what we call a background-independent theory. Loop quantum gravity is such a one; string theory is not.

The debate between proponents of background-dependent and background independent theories is in fact just the modern version of an ancient debate. Since the Greeks, the argument has raged between those who believed that space and time have an eternally fixed, absolute character and those who thought space and time are no more than relations between events that themselves evolve in time. Plato, Aristotle, and Newton were absolutists. Heraclites, Democritus, Leibniz, Mach, and Einstein were relationalists. When we demand that the quantum theory of gravity be background-independent, we are saying we believe that the triumph that general relativity represented for the relational point of view is final and will not be reversed.

Much of the argument between string and loop theorists is a continuation of this debate. Most string theorists were trained as elementary-particle physicists and worked their whole lives in a single fixed spacetime. Many of them have never even heard of the relational/absolute debate, which is the basic historical and philosophical context for Einstein's work. Most people who work in loop quantum gravity do so because at some point in their education they understood the relational, dynamical character of spacetime as described in general relativity, and they believe in it. They don't work on string theory because they cannot take seriously any candidate for a quantum theory of gravity that is background-dependent and hence loses (or at best hides) the relational, dynamical character of space and time.

Similarly, at first string theorists were resistant to the idea that the fundamental theory must be background-independent. However, I think that by now almost all string theorists have come around. They did so because there are reasons internal to string theory to believe that the fundamental theory must be background-independent. This is because string theory turned out to be non-unique. While the original hope, back in the 1980s, was that mathematical consistency would suffice to determine the unified theory, it turns out that in fact there are a huge number of equally consistent string theories. Each is as consistent as any other and each depends on a different choice of fixed background. Further, in spite of the huge numbers of string theories we know about, none of them agree with observations on the three points I mentioned above.

http://www.edge.org/3rd_culture/smolin03/smolin03_p5.html

Moving Dimensions theory, with the notion of a fourth dimension expanding at a rate of c relative to the three spatial dimensions, offers a connection between loop quantum gravity and string theory, but who needs string theory's absurdities, unless you're trying to raise government grants?

Moving Dimesnions Theory: http://physicsmathforums.com

[mcgucken]

Physicists are good at approximations.

Can any physicist out there approximate how many hundreds of millions of dollars have been invested into the postmodern hoax that is called string theory?