Do null defects dream of conformal symmetry?
- 1Institut des Hautes Études Scientifiques
- 2Stony Brook University
Abstract
A bstract : We initiate the study of null line defects in Lorentzian conformal field theories in various dimensions. We show that null lines geometrically preserve a larger set of conformal isometries than their timelike and spacelike counterparts, explain a connection to non-relativistic systems, and constrain correlation functions using conformal Ward identities. We argue that having conformal symmetry, and especially maximal conformal symmetry, is extremely constraining — nearly trivializing systems. We consider the (3+1)d scalar pinning field and null Wilson line examples in depth, compare their results to ultraboosted limits of timelike and spacelike systems, and argue that shockwave-type solutions are generic. A number of physical consistency conditions compel us to consider defect correlators as distributions on a restricted subspace of Schwartz test functions. Consequently, we provide a resolution to the longstanding problem of ultraboosted limits of gauge potentials in classical electromagnetism. We briefly analyze semi-infinite sources for the scalar in (4 − ϵ )-dimensions, consider solutions on the Lorentzian cylinder, and introduce the “perfect null polygon” which emerges for compatibility between Gauss’ law and ultraboosted limits.
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BibTeX
@article{erramilli2026null,
title = {{Do null defects dream of conformal symmetry?}},
author = {Rajeev S. Erramilli and Justin Kulp and Fedor K. Popov},
journal = {Journal of High Energy Physics},
year = {2026},
month = oct,
doi = {10.1007/jhep10(2026)095},
url = {https://link.springer.com/10.1007/JHEP10(2026)095},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Do null defects dream of conformal symmetry?
AU - Rajeev S. Erramilli
AU - Justin Kulp
AU - Fedor K. Popov
PY - 2026
DA - 2026/10/08
JO - Journal of High Energy Physics
DO - 10.1007/jhep10(2026)095
UR - https://link.springer.com/10.1007/JHEP10(2026)095
AB - A bstract : We initiate the study of null line defects in Lorentzian conformal field theories in various dimensions. We show that null lines geometrically preserve a larger set of conformal isometries than their timelike and spacelike counterparts, explain a connection to non-relativistic systems, and constrain correlation functions using conformal Ward identities. We argue that having conformal symmetry, and especially maximal conformal symmetry, is extremely constraining — nearly trivializing systems. We consider the (3+1)d scalar pinning field and null Wilson line examples in depth, compare their results to ultraboosted limits of timelike and spacelike systems, and argue that shockwave-type solutions are generic. A number of physical consistency conditions compel us to consider defect correlators as distributions on a restricted subspace of Schwartz test functions. Consequently, we provide a resolution to the longstanding problem of ultraboosted limits of gauge potentials in classical electromagnetism. We briefly analyze semi-infinite sources for the scalar in (4 − ϵ )-dimensions, consider solutions on the Lorentzian cylinder, and introduce the “perfect null polygon” which emerges for compatibility between Gauss’ law and ultraboosted limits.
SN - 1029-8479
ER -