nLab exotic brane

Idea

In string theory, by “exotic branes” [deBoer & Shigemori (2012)] one means first of all $p$-branes of small codimension $D-1-p \leq 2$ (“non-standard branes” Bergshoeff & Riccioni (2012)), such as

• D7-branes (codimension 2 defect branes),

• D8-branes and maybe M9-branes (codimension 1)

• D9-branes (codimension 0).

More generally, exotic branes have been argued to be U-duality-twisted objects in non-geometric backgrounds.

According to deBoer & Shigemori 2012, p. 12 all these may be identified as codimension-2 defect branes with U-duality-group monodromy.

Figure 1 from (BMO19). «A comparison of the objects covered by the geometric solutions (backed by orange hashing) and non-geometric solutions (backed by green hashing) out of all the branes down to codimension-$2$ and¹ $0\leq\alpha\leq -2$, as well as their M-theory lifts. Red lines denote T-duality, blue lines denote lifts/reductions and black lines denote S-dualities.»

Related concepts

• non-geometry, T-fold

• double field theory

• defect brane

References

Branes of codimension $\leq 2$ are called non-standard branes in:

• Eric A. Bergshoeff, Fabio Riccioni, Solitonic branes and wrapping rules, Phys. Part. Nuclei 43 (2012) 557–561 [doi:10.1134/S106377961205005X]

  (see also at solitonic brane)

The terminology “exotic branes” is due to:

• Jan de Boer, Masaki Shigemori, Exotic Branes in String Theory, Physics Reports 532 (2013) 65-118 (arXiv:1209.6056, doi:j.physrep.2013.07.003)

  (discussion as defect branes with U-duality-group monodromy)

• David Berman, Felix J. Rudolph, Branes are Waves and Monopoles [arXiv:1409.6314]

• Jose J. Fernandez-Melgarejo, Tetsuji Kimura, Yuho Sakatani, Weaving the Exotic Web, JHEP 2018 72 (2018) [doi:10.1007/JHEP09(2018)072]

• David S. Berman, Edvard T. Musaev, Ray Otsuki, Exotic Branes in Exceptional Field Theory: $E_{7(7)}$ and Beyond, J. High Energ. Phys. 2018 53 (2018) [arXiv:1806.00430v4, doi:10.1007/JHEP12(2018)053]

• David Berman, Edvard Musaev, Ray Otsuki, Exotic Branes in M-Theory, contribution to: Dualities and Generalized Geometries, Corfu Summer Institute 2018 (arXiv:1903.10247)

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1. Here $\alpha$ denotes the exponent with which the brane’s tension $T$ scales with the string coupling constant $g_s$ as $T \propto (g_s)^\alpha$, according to BMO 2019, p. 2. ↩