<!-- Mentioned at #gravitylunch when i asked about how to separate gravitational parts and matter parts in the action. --> # Vasiliev theory The **Vasiliev** theory is an interesting class of gravitational theories containing infinitely many higher-spin fields. There is a very large gauge group that includes the diffeomorphism group as a subset. Higher spin fields are generally bad. For example, they can have causality issues (see [[2014#Camanho, Edelstein, Maldacena, Zhiboedov]]) and violate the [[0008 Quantum chaos|chaos]] bound (see [[2016#Perlmutter]] and [[2022#Wang, Wang]]). But if there are infinitely many of them, these kinds of pathology may be absent! In some sense, the bad things sum up to zero. ## Refs - OG: [[Vasiliev1990]][](https://www.sciencedirect.com/science/article/abs/pii/0370269390914006) and [[Vasiliev2003]][](https://arxiv.org/abs/hep-th/0304049) - [Yin's talk at KITP](http://online.kitp.ucsb.edu/online/bitbranes_c12/yin/) - dual - critical O(N) model [[KlebanovPolyakov2002]][](https://arxiv.org/abs/hep-th/0210114) - [[SezginSundell2002]][](https://arxiv.org/abs/hep-th/0112100) - three-point function: [[GiombiYin2009]][](https://arxiv.org/abs/0912.3462) and [[GiombiYin2010]][](https://arxiv.org/abs/1004.3736) - contraints - [[2011#Maldacena, Zhiboedov]]: exactly conserved higher spin current => CFT is free - [[MaldacenaZhiboedov2012]][](https://arxiv.org/abs/1204.3882): approximate higher spin symmetry => CFT three point function is constrained - explicit mapping - [[2022#Aharony, Chester, Sheaffer, Urbach]]