Carroll-invariant propagating fields

Carrollian field theories have recently emerged as a candidate dual to flat space quantum gravity. We carefully quantize simple two-derivative Carrollian theories, revealing a strong sensitivity to the ultraviolet. They can be regulated upon being placed on a spatial lattice and working at finite inverse temperature. Unlike in conventional field theories, the details of the lattice-regulated Carrollian theories remain important at long distances even in the limit that the lattice spacing is sent to zero. We use that limit to define interacting continuum models with a tractable perturbative expansion. The ensuing theories are those of generalized free fields, with non-Gaussian correlations suppressed by positive powers of the lattice spacing, and an unbroken supertranslation symmetry.

Quantizing Carrollian field theories

Cotler,

Jensen,

Prohazka

et al. 2024

The Carrollian limit of ModMax electrodynamics

Correa,

Hernández,

Oliva

2024

We consider the Carrollian limit of ModMax electrodynamics, namely the limit of vanishing speed of light, for the most general, four-dimensional, duality and conformal invariant electromagnetism. The theory is parameterized by a unique real constant γ, which remains playing a non-trivial role in the magnetic Carrollian case, while it can be removed in the electric Carrollian contraction, and we therefore focus in the former. Applying the technique of Lie point symmetries, we obtain that the magnetic limit is invariant under the Carrollian group, as well as under the local translation in Carrollian time x0→ x0′ = x0+f (xi) and xi→ xi′ = xi, with f being an arbitrary function. A diagonal part of the symmetries span the Conformal Carroll algebra of level 2, 𝔠𝔠𝔞𝔯𝔯2 in four dimensions. Two additional internal symmetries remain in the Carrollian limit of ModMax standing for the conformal invariance of the theory, as well as the invariance under duality transformations.

Light transformation: a celestial and Carrollian perspective

Banerjee,

Basu,

Bhatkar

2024

In this paper, we first study the consequence of spacetime translations and Lorentz transformations on Celestial CFT OPEs. Working with the light transforms of the operators belonging to the modified Mellin basis, we found that the leading order singularity in the OPE of such operators could be fixed purely using Poincaré symmetries owing to the non-trivial action of the translations on these operators. The OPE coefficient is then fixed using the soft limit of the correlation functions. We check that this singular structure obtained from symmetries is consistent with the OPE limit of three-point functions. This approach could potentially be useful for studying Celestial CFT without adverting to bulk physics. As another goal, we explore the significance of light transformation in Carrollian CFTs. In the special cases we considered, we show that light transformation equips us with a map between two branches of Carroll CFT in d = 3 dimension at the level of correlation functions in the near coincident limit.