"The king is dead, long live the king!" is a traditional proclamation made following the accession of a new monarch in various countries. Nowadays the phrase is adapted to succession of various kinds. In a monarchy, there can only be one king. The new king is crowned only once the old one dies. Oftentimes when used in an allegorical wat, what dies is not replaced with the same term, but with a new term, such as "The League is dead. Long live the United Nations." However, in our case, the king is the string theory upon whose death a new string theory emerges.
The biggest impediment to people accepting string theory as the theory of everything is the current string theory, who’s like a deranged medieval king. The king scares everyone, but no one is willing to confront him or depose him. What has happened is that the old king is ignored, but not really challenged. The king has locked himself into his castle with provisions for years and years, willing to fight anyone foolish enough to challenge him.
What has happened is that rather than trying to fight the king, the king is ignored and let him hold reign supreme over his “theory of everything” castle, as the rest of physics rolls along with very little input from the castle.
However, this is not how you fight the deranged king. No: you build a siege engine and amass a force that can storm the keep! What you do is find a weak spot and focus your energy in breaching the walls.
And this weak spot is the concept of vibration. The whole idea of the current string theory is that the strings rather mystically vibrate. Not really in a concrete way, as they are one-dimensional and the vibration somehow disappears into the additional dimension mandated by the theory.
You might ask, how can someone come up with such a kooky idea? And how could anyone take the proponents of this theory seriously? The answer is that this abstract concept of vibrations and mystical energy isn’t something invented by string theorists. The concept more or less harkens back to 1920s and the invention of quantum mechanics. Back then, almost a hundred years ago, Schrödinger and company decided that one cannot conceive quantum mechanical phenomena with common sense, because the world is probabilistic.
With the presupposition that the fundamental forces act over a vacuum, without physical contact, the only way to conceive the action of strings is via these ethereal, intangible, forces. And the only form the string theory can take with these presuppositions is that of a multidimensional universe, because that’s what the mathematics looks like.
The concept of vibration as a fundamental feature of the universe is alluring, as we can see vibrations playing an important part in the interactions of solids. However, we’ve never really seen gases vibrate. For liquids, the formation of waves is a similar phenomenon, but even that isn’t really the same. Nevertheless, we see that when someone asks: “why can't strings move at the speed of light?”, they receive an answer steeped in the concept of vibrating strings.
Or more specifically a PhysicsForums member by the name of Dixanadu asked this very question:
Question:
So I'm a bit confused about why strings can't move at the speed of light. I understand that the end points do if the string is open, but the rest of it doesn’t. To paraphrase, really I want to know why you must have timelike and spacelike tangent vectors to a point on the world sheet of a string. Why is it unphysical to have all tanget vectors point in spacelike directions, with just a single lightlike one pointing in the direction of travel? To paraphrase a final time: I know that if the string moves at the speed of light, then a point on the string at time t = 0 is mapped exactly to a point at time t = t, which we can keep track of. So: traveling at the speed of light means we can keep track of each point on the string. But this is not allowed. Why? I'm a noob with this stuff so please try to dumb your knowledge down as much as possible so I can understand. Thank you!
He asked the question, because under the current understanding nothing, except light, can move at the speed of light, only very close to it.
The first answer on the forum goes like this:
Yea, that's good question. It seems that since the string is vibrating at very high frequencies, there would be points on the string that would be moving very fast. And this would limit the whole string from moving near the speed of light. The theoretical limit of a point particle would be the speed of light. But a vibrating string would have to be limited to quite a bit less than the speed of light because some points on the string would be moving very fast with respect to the rest of the string in the direction of motion. Is this a proof that strings are not the correct description of particles?
Let’s pick the answer to pieces.
The phrase “It seems that since the string is vibrating at very high frequencies, there would be points on the string that would be moving very fast” holds the first key to the misunderstanding. In the current theory the strings aren’t orbiting, they are vibrating. Thus, the sentence is completely logical, assuming a vibrating string. The only problem is that the premise is wrong.
Next, “And this would limit the whole string from moving near the speed of light.” This is clearly a problem of all or nothing: one point can move at the speed of light only if all points move at the speed of light.
Next, “The theoretical limit of a point particle would be the speed of light. But a vibrating string would have to be limited to quite a bit less than the speed of light because some points on the string would be moving very fast with respect to the rest of the string in the direction of motion.” This is more or less a repetition of the first misunderstanding. The idea that one bit moves at the speed of light contradicting the slower movement of another bit.
Next, “Is this a proof that strings are not the correct description of particles?” No, I wouldn’t say that this is much proof of any such things, except that the idea of vibrating strings introduces plenty of problems.
Another reply goes like this:
We are reminded here often of the problems with using classical concepts about quantum behavior; particularly, thinking of points as locations is going to be problematic.... If I recall correctly, a typical uncertainty of position of a hydrogen atom is about six diameters. Strings are much smaller - the size of a string compared to the diameter of a proton is supposed to be about the same proportion as the size of a man to the distance of Andromeda galaxy. The visualizations of strings being open or closed, having lengths, or having vibrations as displacements of location are classical conceptions. The tension in the strings is supposed to be high - one would have to suspend a mass of two Andromeda galaxies at the Earth's surface to approach it... Trying to get a casual feel for strings just promotes a cascade of thoughts that make increasingly less sense. I'm an outsider... just suggesting that trying to conceive strings apart from the math in the theory is likely to always go in an unconceivable direction...
Basically, the answer is not saying anything very concrete. But there is again the reference to vibration and this time also to tension.
Here we see a revealing answer:
By quantum string are you referring to a relativistic string? I'm talking about the relativistic (open) string; that its endpoints move at the speed of light. Apparently according to Barton Zwiebach, only the end points move and speed v = c but the rest of the string doesn't. I was wondering why...
Here the questioner expands:
By quantum string are you referring to a relativistic string? I'm talking about the relativistic (open) string; that its endpoints move at the speed of light. Apparently according to Barton Zwiebach, only the end points move and speed v = c but the rest of the string doesn't. I was wondering why...
This reveals the notion that the strings would be open. Alongside the notion of vibration, we see the problem that the strings could have end points.
The questioner continues:
I'll quote Barton Zwiebach: "The end points move with the speed of light. The endpoints move transversely to the string. On the interior of the string, the notion of a velocity is ambiguous. For the string end points, however, the velocity is well defined - there is no ambiguity defining the velocity of the end points!" If you wish you can check out page 124 of chapter 6 in his book: a first course in string theory.
It seems that the notion of the strings having endpoints necessitates that the string must vibrate. And you end up with sentences such as “On the interior of the string, the notion of a velocity is ambiguous”. It goes to show that if you believe that there is other energy not related to the speed of the string, there appears to be some sort of transfer of energy to velocity or other rather new-agey sounding concepts.
If you wish, you can read the whole discussion in the link above. But the deranged king in this case is the idea the energy and velocity would be somehow different and there would be some kind of magical mathematical transmutation from energy to velocity taking place. Or dare I say transubstantiation. The concept that the bread and wine in communion literally transform into the body and the blood of Christ. That there is first one thing that magically transforms into another.
But for a hundred years, almost all mainstream physicists have believed in this transmutation/transubstantiation, because the experiments and mathematics seemed to back it up. In Christianity it took Martin Luther to reject transubstantiation. I guess this blog are my 95 theses to rid physics of superstition.
And to continue with biblical references it was Jesus who happened to say “Do not think that I have come to abolish Law or the Prophets; I have not come to abolish them but to fulfill them” (Matthew 5:17). My point is not to try overturn a single physical law, that is proven experimentally, or shown to be mathematically valid. What my mission is to show that until the superstitious separation of energy and speed is broken, physics cannot advance.
Or more specifically the king who must die is the vibrating open string. And the new king who is crowned is the non-vibrating (apart from collisions) string, moving at the speed of light. And the only reason we don’t see most of this speed is because the speed is tangential to its orbital.
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