- #1

lucas_

- 413

- 23

What is the difference between Volovik and Witten model. Is it Volovik using quantum mechanics as more fundamental to QFT? And Witten not claiming it? Compare this with the claims of Hrvoje Nikolic' that QM is more fundamental than QFT (see https://arxiv.org/pdf/1811.11643.pdf). For those familiar with arguments about it. How do they differ? How popular is this condense matter connection thing among Physicists? Please share the views of each major proponent including Wen and others I haven't mentioned. Thank you.

Witten's https://arxiv.org/abs/1710.01791

"Condensed matter physicists are accustomed to such "emergent" phenomena, so to get an idea about the status of symmetries in an emergent description of Nature, we might take a look at what

happens in that field. Global symmetries that emerge in a low energy limit are commonplace in condensed matter physics. But they are always approximate symmetries that are explicitly violated

by operators of higher dimension that are "irrelevant" in the renormalization group sense. Thus the global symmetries in emergent descriptions of condensed matter systems are always analogous to Le L or L L in the Standard Model { or to strangeness, etc., from the point of view of QED or QCD.

By contrast, useful low energy descriptions of condensed matter systems can often have exact gauge symmetries that are "emergent," meaning that they do not have any particular meaning in the microscopic Schrodinger equation for electrons and nuclei. The most familiar example would be the emergent U(1) gauge symmetries that are often used in effective field theories of the fractional quantum Hall effect in 2 + 1 dimensions. These are indeed exact gauge symmetries, not explicitly broken by high dimension operators. Gauge theory with explicit gauge symmetry breaking is not ordinarily a useful concept."