What is 3rd quantization and what can be learned from it?

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Discussion Overview

The discussion revolves around the concept of 3rd quantization in the context of quantum mechanics and quantum field theory (QFT). Participants explore the potential implications of iterating the quantization process beyond the established first and second quantization frameworks, examining how this might relate to string field theory and other theoretical constructs.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that 1st quantization relates to particles in a potential, producing wavefunctions, while 2nd quantization involves quantum field theory, which quantizes these wavefunctions.
  • Others suggest that 3rd quantization could provide insights into which fields are permissible in the framework of 2nd quantization, potentially linking properties of different fields.
  • One participant mentions that string field theory can be viewed as a form of 3rd quantization, contrasting it with string theory, which is seen as 2nd quantized.
  • Another participant expresses a desire for a clear progression from 1st to 3rd quantization, seeking literature that outlines how outputs of one quantization process serve as inputs for another.
  • Concerns are raised regarding the abstract nature of existing literature on the topic, with a request for more concrete formulas and explanations of the relationships between quantization levels.
  • A participant introduces the idea of viewing quantization through an abstract information lens, suggesting that each level of quantization represents a broader "window" of understanding, but questions the infinite continuation of this process.

Areas of Agreement / Disagreement

Participants express a range of views on the nature and implications of 3rd quantization, with no consensus reached on its definition or significance. Disagreements exist regarding the interpretation of string theory and its relation to 3rd quantization, as well as the adequacy of existing literature.

Contextual Notes

Participants note limitations in the current understanding of the formalization of quantization processes and the need for clearer connections between different quantization levels. There is also mention of unresolved questions regarding the implications of quantization on theoretical frameworks.

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I've heard that the quantum mechanics of particles in a potential is called 1st quantization which produces wavefunctions. And I've heard that quantum field theory is called 2nd quantization which in turn quantizes the wavefunctions. Can this process be iterated to give 3rd quantization, and what would that tell us?

As I understand it, 1st quantization gives distribution functions for variables such as position and momentum. And 2nd quantization uses the functions of 1st quantization to get distribution functions for fields that can be used to calculate the excitation modes of fields that are interpreted as particles. Would 3rd quantization tell us which fields are allowed to exist in the first place that are then used in 2nd quantization? If so, then it seems to me that a 3rd quantization procedure might give us a relationship between QFT fields so that if we measured a property of one kind of field (say the EM field), it would automatically give us the properties of other kinds of fields (say the Strong Force) by means of this relationship between the kinds of fields that are allowed to exist. Any literature on this out there? Thanks.
 
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3rd quantization is one way to think of what is happening in string field theory, although no one calls it that. In SFT, strings are quanta of a string field. The various modes of a string correspond to various spacetime fields, whose quanta are particles. And these particles have quantized position, momentum, etc.
 
String field theory can be said to be "3rd quantized", whereas string theory is "2nd quantized".

ie. while the quantization of string theory (which leads to different gauge and matter field) proceeds very similar to quantization in point quantum mechanics, string field theory is similar to point QFT.
 
What I guess I'm looking for is a summary of a natural progression from 1st to 2nd to 3rd quantization procedure - how the output of one is the input of the other - and how one is constrained by the higher order procedure. Is there anything like that in the literature? Thanks.
 
Fra said:
See the informal musings from Baez: http://math.ucr.edu/home/baez/nth_quantization.html

/Fredrik

I read that, thank you. It was too abstract for me. He made a number of statements about how to interpret the math that I am unable to evaluate. I'm left having to take his word for it, and I'm really not comfortable with that. He seems to think that string theory is 3rd quantization. But I have to wonder what the loop quantum gravity people would have to say about that. It would be easier for me if someone could show me the formulas in each of the 1st, 2nd, and 3rd quantization procedures, identify the variables in each, show how the output of one is being used as the input of the other, and explain what information is gained in each.
 
I'm on my way out in a moment so I can't expand, but IMO the best way to understand this is to stop thinking in terms of "particles" and other "mechanical pictures". The way I see it is that an a more abstract information picture, quantization is like an induction step. But there is a good reason (the formalization isn't fleshed out though) why this does not yield an infinite tower of turtles, and that IMHO has to do with limiting information capacity. All we see is a "window" of this tower. One step classical-QM is the smallest window of course. In 2nd quantization it's a bigger window.

But I noticed I wrote some fuzzy ramblings about this several years ago in this thread
https://www.physicsforums.com/showthread.php?t=221158

My own views are costantly beeing refined and worked on but maybe it can gives some ideas.

One can also see this in a hierarcy of broken ontologies, where empirical support breaks the old effective ontology which then forces us to apply the same trick again. but I think the real insight is WHY this infinite tower of quantization along can't make sense, and why it is truncated. Obviously each step adds complexity and encoding requirements.

But I don't recall reading a formalization of this, in they WAY I would want to do it. Baez provoces questions there...but he doesn't provide all answers IMO.

/Fredrik
 

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