Light-ray moments as endpoint contributions to modular Hamiltonians

Daniel Kabat, Gilad Lifschyt, Phuc Nguyen, Debajyoti Sarkar

Research output: Contribution to journalArticlepeer-review


We consider excited states in a CFT, obtained by applying a weak unitary perturbation to the vacuum. The perturbation is generated by the integral of a local operator J(n) of modular weight n over a spacelike surface passing through x = 0. For |n| ≥ 2 the modular Hamiltonian associated with a division of space at x = 0 picks up an endpoint contribution, sensitive to the details of the perturbation (including the shape of the spacelike surface) at x = 0. The endpoint contribution is a sum of light-ray moments of the perturbing operator J(n) and its descendants. For perturbations on null planes only moments of J(n) itself contribute.

Original languageEnglish
Article number74
JournalJournal of High Energy Physics
Issue number9
StatePublished - Sep 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).


  • Conformal Field Theory
  • Field Theories in Higher Dimensions
  • Field Theories in Lower Dimensions

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


Dive into the research topics of 'Light-ray moments as endpoint contributions to modular Hamiltonians'. Together they form a unique fingerprint.

Cite this