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Kittel Knight
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Is there any relationship between String Theory and ZPE?
I mean, does ST offer anything new, any new reason to ZPE?
Thanks!
I mean, does ST offer anything new, any new reason to ZPE?
Thanks!
Are you hoping that ZPE is something *physical* ?Kittel Knight said:Is there any relationship between String Theory and ZPE?
I mean, does ST offer anything new, any new reason to ZPE?
Thanks!
Thanks, Mitchell !mitchell porter said:Supersymmetry, which is a feature of string theory, makes ...
Did anyone say that?!Careful said:Are you hoping that ZPE is something *physical* ?
Kittel Knight said:Did anyone say that?!
Well, you make ''another'' argument here, but your conclusion is the same as mine (I didn't give those scenario's much thought anyway). But still, you kind of did not respond to my first comment because somehow, these neutralino's shouldn't disturb Newton's law where it is supposed to hold. That's quite unlikely no? Or am I missing something, is there a reason why the neutralino's should be where they are supposed to be ?Haelfix said:If we are talking about weak scale supersymmetry, then indeed the lightest superpartner is a candidate term for dark matter and happens to be around the right range by dimensional analysis. It is of course the only possible particle in that scenario, since on general grounds the other superpartners decay away much too rapidly and you just wouldn't expect for there to be many around so late in the universe's history.
Careful said:Are you hoping that ZPE is something *physical* ?
I will respond later, have to go and entertain my kids nowlumidek said:ZPE is physical whenever it couples to gravity; and whenever one may compare the total energy between two configurations with different net values of ZPE. In other words, ZPE is almost always physical.
In particular, the cosmological constant - which is physical because it makes the expansion of the Universe accelerate - has contributions from ZPEs from all known fields in Nature. The expected largeness of these terms - so much larger than the observed cosmological constant - is called the cosmological constant problem.
But there are also "non-problematic" examples of the ZPE. ZPE of the electromagnetic field (coming from all the allowed standing wave modes) between two metallic plates depends on the plates' distance. That's why the gradient of this total energy will be demonstrated as the Casimir force - an effect that's been experimentally verified to agree with the predictions fully based on ZPEs.
After all, the negative binding energy of the Hydrogen atom, any other atom, or any other quantum physical system is nothing else than a generalization of ZPE for different-than-quadratic potentials. All these things are totally physical and observable.
One must be very careful about ZPEs in string theory because they're the simplest players to demonstrate many effects.
For example, the very critical dimension D=26 of the bosonic string and D=10 of the superstring may be derived from the ZPEs. For example, in the bosonic case, there are D-2 transverse bosonic oscillators of a bosonic string. Each of them gives a hbar.omega/2 ZPE. However, the frequencies depend on the wave number along the string and one must sum over them. So the total ZPE of these vibrations is proportional to
(D-2) x sum (n/2)
The sum goes over n from 1 to infinity.
Here, D-2 comes from the number of transverse directions, n comes from the wave number (in frequency), and 1/2 is from hf/2. The first excited state must be massless because we only have (D-2) states at this level - from D-2 transverse oscillators - instead of (D-1) that would be needed for the little group of a massive particle. That means that
(D-2) x sum (n/2) + 1 = 0.
However, the sum of positive integers is -1/12, so we have
(D-2) x (-1/24) = -1,
D-2 = 24,
D = 26,
the right critical dimension. This calculation is not just a funny dirty trick, it's the actual conformally correct calculation that may be phrased in a more formal regulated framework but the essence of the calculation will be the calculation above, anyway.
There exist equivalent ZPE-based calculations of the critical dimension. In the covariant formalism, the bc-ghosts actually have the central charge c=-26, requiring D=26 bosons to cancel the conformal anomaly on the world sheet. The c=-26 result may also be reduced to some kinds of ZPE terms.
In supersymmetric theories, ZPEs typically tend to cancel.
At any rate, string theory makes these features of quantum theory more important, not less important or more disputable. Any hope that string theory would "undo" some of the key insights of the quantum revolution or relativistic revolution is totally misguided. String theory is another step in the progress towards more accurate and more complete physical theories - perhaps the last step. It is surely not a step to return physics to the 19th, 18th, or 17th century. ;-)
Careful said:I will respond later, have to go and entertain my kids now
Haha, no they immediately learn the distinction between physical principles and particular mathematical representations of them so that they are not fooled into thinking than the conclusions of one particular choice of representation lead to an inescapable *physical* paradoxlumidek said:I hope that you're not educating them to think that ZPE is unphysical. That would be unacceptable even for an arrogant sub-par scientist such as Leslie Winkle. ;-)
haushofer said:A related question which never became clear to me: in string theory you have multiple ways of regularize. From the CFT side of the story you can understand the -1/12 as ZPE quite good I would say, but one can also use exponential regularization or analytic continuation.
haushofer said:A related question which never became clear to me: in string theory you have multiple ways of regularize. From the CFT side of the story you can understand the -1/12 as ZPE quite good I would say, but one can also use exponential regularization or analytic continuation. All these methods yield the same -1/12, while naively these methods differ in plausibility. Why do these methods all yield the same answer?
String Theory is a theoretical framework in physics that attempts to explain the fundamental nature of particles and the forces that govern them by describing them as tiny vibrating strings rather than point-like particles.
ZPE, or Zero Point Energy, is a concept in quantum physics that refers to the lowest possible energy that a quantum mechanical physical system may have. It is sometimes referred to as the vacuum energy or ground state energy.
There is currently no proven connection between String Theory and ZPE. While some theories suggest that ZPE could play a role in String Theory, it is still a topic of ongoing research and debate among scientists.
Some theories propose that ZPE could provide the necessary energy for the vibration of strings in String Theory. It is also possible that ZPE could help explain certain phenomena, such as the expansion of the universe, that are currently unexplained by String Theory.
If a connection between String Theory and ZPE were to be established, it could potentially provide a more complete understanding of the fundamental nature of the universe and could lead to new advancements in physics and technology. However, more research and evidence is needed before any firm conclusions can be drawn.