Schreiber SuGra via Superspace Bianchis

A talk that I will have given:

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• Urs Schreiber:

  
  

  11D Supergravity with M5 Probes via Superspace Bianchis

  
  

  talk at:

  Fundamental Challenges in Theoretical Physics Workshop —

  Symmetries, Protected Quantities, and Exact Computations in Supergravity

  Johanneshof near Munich

  29 Jun - 3 Jul 2026

Abstract. It is physics folklore that on-shell supergravities are given by imposing torsion constraints and flux Bianchi identities in superspace. But the historical literature has shied away from complete proofs.

Remarkably, the full (and computer-checked) new proof by GSS24 shows that on-shell 11D supergravity is equivalent to the Bianchi identities/Gauss laws for the duality symmetric C-field super-flux densities over a supertorsion-free superspacetime. Similarly for the “self-dual higher gauge field” on M5-brane probes super-embedded into such 11D SuGra backgrounds.

The talk will give an exposition of this situation, including of the status of “rheonomy” and of constructing full M5-superembeddings.

We end with an outlook on how this remarkable situation implies global completion of 11D SuGra+M5-probes by flux quantization laws (aka “models of the C-field”) in unstable/nonabelian cohomology (“Hypothesis H”). Via “geometric engineering” this makes testable predictions for topological quantum material phenomenology.

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Based on:

• Flux Quantization on 11D Superspace [doi:10.1007/JHEP07(2024)082]

• Flux Quantization on M5-Branes [doi:10.1007/JHEP10(2024)140]

• Holographic M-Brane Super-Embeddings [doi:10.1142/S0129055X25500230]

• Engineering of Anyons on M5-Probes [doi:10.21468/SciPostPhysLectNotes.107]

(with G. Giotopoulos and H. Sati).