The answer to this depends on what degree of subtlety you want to take the question to. The move from finite to infinite DoFs is always delicate in parts.

If, for example, you've read literature on the thermodynamic limit of statistical mechanics, and it all seems straightforward to you, then yes, QFT reduces to QM, as declared by Yuji and lots of upvoters, although I consider the lack of any citation in Yuji's Answer somewhat telling. If you think the thermodynamic limit is fraught, then you will likely think the same of the reduction from QFT to QM. AFAIK, however, an effective and simple statement of what the problem(s) might be, if any, does not exist, as exemplified by Vladimir's problematic Answer.

Renormalization, as a way to handle the move to infinite DoFs on a Lorentzian manifold with nontrivial evolution, certainly plays a part in any reservation one might have, but many Physicists now take the view that the renormalization group is an adequate way to deal with the mathematics. Most of the books on condensed matter theory that Yuji recommends, whether QFT or otherwise, largely gloss the harder mathematical worries one might have about renormalization.

Your apparent acceptance of Ehrenfest as a good enough reduction from quantum to classical mechanics suggests that for you the answer to your Question is yes. However, Ehrenfest's theorem is by no means entirely acceptable to all Physicists. It's a digression from the QFT/QM topic of your Question, but, for example,

Phys. Rev. A 50, 2854–2859 (1994)

Inadequacy of Ehrenfest’s theorem to characterize the classical regime

L. E. Ballentine, Yumin Yang, and J. P. Zibin

**Abstract:** The classical limit of quantum mechanics is usually discussed in terms of Ehrenfest’s theorem, which states that, for a sufficiently narrow wave packet, the mean position in the quantum state will follow a classical trajectory. We show, however, that that criterion is neither necessary nor sufficient to identify the classical regime. Generally speaking, the classical limit of a quantum state is not a single classical orbit, but an ensemble of orbits. The failure of the mean position in the quantum state to follow a classical orbit often merely reflects the fact that the centroid of a classical ensemble need not follow a classical orbit. A quantum state may behave essentially classically, even when Ehrenfest’s theorem does not apply, if it yields agreement with the results calculated from the Liouville equation for a classical ensemble. We illustrate this fact with examples that include both regular and chaotic classical motions.

PRA link: http://link.aps.org/doi/10.1103/PhysRevA.50.2854

DOI: 10.1103/PhysRevA.50.2854

For someone who moves very well between classical, QM, and QFT, from whom I got the link above, I suggest

Between classical and quantum

N.P. Landsman

arXiv:quant-ph/0506082v2

**Abstract:** The relationship between classical and quantum theory is of central importance to the philosophy of physics, and any interpretation of quantum mechanics has to clarify it. Our discussion of this relationship is partly historical and conceptual, but mostly technical and mathematically rigorous, including over 500 references. On the assumption that quantum mechanics is universal and complete, we discuss three ways in which classical physics has so far been believed to emerge from quantum physics, namely in the limit h -> 0 of small Planck's constant (in a finite system), in the limit of a large system, and through decoherence and consistent histores. The first limit is closely related to modern quantization theory and microlocal analysis, whereas the second involves methods of C*-algebras and the concepts of superselection sectors and macroscopic observables. In these limits, the classical world does not emerge as a sharply defined objective reality, but rather as an approximate appearance relative to certain "classical" states and observables. Decoherence subsequently clarifies the role of such states, in that they are "einselected", i.e. robust against coupling to the environment. Furthermore, the nature of classical observables is elucidated by the fact that they typically define (approximately) consistent sets of histories. We make the point that classicality results from the elimination of certain states and observables from quantum theory. Thus the classical world is not created by observation (as Heisenberg once claimed), but rather by the lack of it.

Comments: 100 pages, to appear in Elsevier's Handbook of the Philosophy of Physics *[which it has]*

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