Is the String Field of String Field Theory the same (ontologically identical to) as the field of QFT?
Disclaimer: Although my maths is quite good and I have a background in computer science and software engineering, I am a philosopher specialising in information theory (and what is called the philosophy of information) so please be kind if you can. I am terribly nooby and may say dumb things.
I have read <PERSON> Not Even Wrong, this neato blog, I have had a look at this post, and this one, and this one. (and this)
I have a very basic understanding of the concept of first and second quantised theories. I also more or less get the following (see the disclaimer above):
1. M-Theory is the current best version of string theory, having been unified from several (five - I think) separate string theories by <PERSON> in the late 1980s
2. There is ample physical/experimental evidence in support of QFT and the quantum field, but not very much at all for String theory and its membranes.
3. The quanta of QFT are excitations in (emerging from) the quantum field, and these are the (reductive) basis of the existence of the different particles of the standard model of quantum/particle physics
4. Strings are not quanta qua/per QM and QFT: they are mathematically and presumably ontologically (this goes to my question) different beasts
5. Membranes might intersect (M-Theory) with membranes in other universes, providing a physico-mathematical formalism that accomodates many worlds interpretations of QM (I think - I am not too sure about that)
6. 651
String theory is apparently very mathematically elegant with respect to representing/modelling many phenomena
Now. I realise that there are a lot of mathematical constructs deployed in QM and QFT and that there are debates relating to such things as interpretations of QM about which ones correspond to physical entities (like operators for example) in the actual mind, mathematics, and language independent physical/material natural world that is the subject of investigation in experimental physics (i.e. - the physical universe or multiverse depending on which one we turn out contingently to be living in).
I also understand that string field theory is much less developed than quantum field theory. However, when I try to get a quick concept of how the string field relates to the quantum field ontologically, I end up facing what seem to be contradictions (which I am sure are largely down to my ignorance.)
For example - there is a book available (which book is probably fantastic - I have not read it) the title of which is "Quantum Field Theory of Point Particles and Strings (Frontiers in Physics)" and for which the abstract says:
The purpose of this book is to introduce string theory without assuming any background in quantum field theory. Part I of this book follows the development of quantum field theory for point particles, while Part II introduces strings. All of the tools and concepts that are needed to quantize strings are developed first for point particles. Thus, Part I presents the main framework of quantum field theory and provides for a coherent development of the generalization and application of quantum field theory for point particles to strings....The book is unique in that it develops all three representations of quantum field theory (operator, functional <PERSON>, and path integral) for point particles and strings. In many cases, identical results are worked out in each representation to emphasize the representation-independent structures of quantum field theory.
So it's clearly the case that many mathematical apparatus deployed in QFT can be deployed for string field theory. HOWEVER - is this supposed to correspond to identity of the fields referred to by the two theories in the physical ontology of the natural world (each theory has a theory-ontology: do both map to the same external physical ontology w.r.t the field of each)?
Moreover, the wikipedia page about string theory starts thus: "String field theory (SFT) is a formalism in string theory in which the dynamics of relativistic strings is reformulated in the language of quantum field theory."
Note that it says "language of quantum field theory", which leads me to believe it is probably a text to get QFT theorists to understand string theory and the string field using language they understand.
So my dumb question boils down to this: is the field of string field theory (meant to be identical to) the quantum field in ontological terms? 800