External probes of conformal field theories (CFTs) introduce novel observables and provide new insights into their structure. Well-known examples include CFTs in curved space, at finite temperature, or with a non-zero chemical potential. A key tool in this exploration is the low-energy effective action, which can be systematically constructed using symmetry principles. In this talk, we will focus on three-dimensional CFTs with a global U(1) symmetry coupled to a background magnetic field. Assuming that the magnetic field drives the CFT to a gapped phase, we will examine the associated effective action and use it to define two-point functions of the conserved current and stress-energy tensor. Leveraging dispersive arguments, we will derive constraints on the effective action coefficients and explore their implications for physically relevant observables.
By Anders Sandvik
By Giulia Fardelli
By Andreas Läuchli
By Igor Herbut
By Subir Sachdev
By Christian Voinea
By Max Metliski
By Mykola Dedushenko
By Ruihua Fan
By Francesco Parisen-Toldin
By Zheng Zhou
By Johannes Hofman
By Giulio Biroli
By Giulio Biroli
