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.
De Anders Sandvik
De Giulia Fardelli
De Andreas Läuchli
De Igor Herbut
De Subir Sachdev
De Christian Voinea
De Max Metliski
De Mykola Dedushenko
De Ruihua Fan
De Francesco Parisen-Toldin
De Zheng Zhou
De Johannes Hofman
De Giulio Biroli
De Giulio Biroli
