This is an introduction to the method of effective field theory. As an application, I derive the effective field theory of low energy excitations in a conductor, the Landau theory of Fermi liquids, and explain why the high- $T_c$ superconductors must be described by a different effective field theory.This is an introduction to the method of effective field theory. As an application, I derive the effective field theory of low energy excitations in a conductor, the Landau theory of Fermi liquids, and explain why the high-$T_c$ superconductors must be described by a different effective field theory.

arXiv:hep-th/9210046Oct 8, 1992242 citations

EFFECTIVE FIELD THEORIES

Ira Z. Rothstein

WORLD SCIENTIFIC eBooksSep 1, 200429 citations

EFFECTIVE FIELD THEORyl

Howard M. Georgi

Jan 1, 19930 citations

Effective Field Theory of Conformal Boundaries

Oleksandr Diatlyk, Himanshu Khanchandani, Fedor K. Popov +1 more

We introduce an effective field theory (EFT) for conformal impurity by considering a pair of transversely displaced impurities and integrating out modes with mass inversely proportional to the separation distance. This EFT captures the universal signature of the impurity seen by a heavy local operator. We focus on the case of conformal boundaries and derive universal formulas from this EFT for the boundary structure constants at high energy. We point out that the more familiar thermal EFT for conformal field theory is a special case of this EFT with distinguished conformal boundaries. We also derive, for general conformal impurities, nonpositivity and convexitylike constraints on the Casimir energy which determines the leading EFT coefficient.We introduce an effective field theory (EFT) for conformal impurity by considering a pair of transversely displaced impurities and integrating out modes with mass inversely proportional to the separation distance. This EFT captures the universal signature of the impurity seen by a heavy local operator. We focus on the case of conformal boundaries and derive universal formulas from this EFT for the boundary structure constants at high energy. We point out that the more familiar thermal EFT for conformal field theory is a special case of this EFT with distinguished conformal boundaries. We also derive, for general conformal impurities, nonpositivity and convexitylike constraints on the Casimir energy which determines the leading EFT coefficient.

arXiv:2406.01550Physical Review LettersDec 31, 202413 citations

The Unruh Effect and Theory Interpretation in an Effective Framework

Marco Maggiani

I discuss the ontological implications of the Unruh effect if quantum field theory is taken to be an effective theory. In the context of the “algebraic” approach to the philosophy of quantum field theory, the Unruh effect can be exploited to construct arguments against particle interpretations. I argue that, since those arguments make use of the notion of fundamentality in a possible world, they cannot be understood in a framework that takes quantum field theory to be an effective theory. I then propose a reformulation that is valid for effective field theories. I conclude by noting that, given that analogous arguments against field interpretations can be made in the algebraic context but not in the effective one, arguments against particles from the Unruh Effect are much more powerful in the latter. I also present a method for interpreting effective theories along the way.I discuss the ontological implications of the Unruh effect if quantum field theory is taken to be an effective theory. In the context of the “algebraic” approach to the philosophy of quantum field theory, the Unruh effect can be exploited to construct arguments against particle interpretations. I argue that, since those arguments make use of the notion of fundamentality in a possible world, they cannot be understood in a framework that takes quantum field theory to be an effective theory. I then propose a reformulation that is valid for effective field theories. I conclude by noting that, given that analogous arguments against field interpretations can be made in the algebraic context but not in the effective one, arguments against particles from the Unruh Effect are much more powerful in the latter. I also present a method for interpreting effective theories along the way.

Philosophy of PhysicsJan 1, 20250 citations

Effective field theory, past and future

Steven Weinberg

WORLD SCIENTIFIC eBooksMay 23, 201669 citations

T_c

superconductors must be described by a different effective field theory.