In the last few years, a remarkable link has been established between the soft theorems and asymptotic symmetries of quantum field theories: soft theorems are Ward identities of the asymptotic symmetry generators. In particular, the tree-level subleading soft theorems are the Ward identities of the subleading asymptotic symmetries of the theory, for instance divergent gauge transformation in...
I will review an old puzzle related to the breakdown of the semiclassical description of the thermodynamics of very cold (ultraspinning) black holes. Then, I will discuss recent work where we resolved this puzzle by properly accounting for quantum corrections arising from graviton loops, which dominate the low-temperature thermodynamics.
This talk is based on work in progress with Giuseppe Bogna. We consider the twistor description of classical self-dual Einstein gravity in the presence of a cosmological constant and a defect operator wrapping a certain $\mathbb{CP}^1$. The backreaction of this defect deforms the flat twistor space to that of quaternionic Taub-NUT space, a certain self-dual limit of a family of Kerr Taub-NUT...
We show that a 2D CFT consisting of a central charge c Liouville theory, a chiral level one, rank N Kac-Moody algebra and a weight −3/2 free fermion holographically generates 4D MHV leaf amplitudes associated to a single hyperbolic slice of flat space. Celestial amplitudes arise in a large-N and semiclassical large-c limit, according to the holographic dictionary, as a...
Based on an idea of Kevin Costello, I will show how to construct a double cover of the twistor space of $\mathbb{R}^4$, $X = \pi^*(\mathcal{O}(1)\oplus\mathcal{O}(1))\to\Sigma$ where $\Sigma$ is an (hyper)elliptic curve. I then discuss how holomorphic theories such as BF and Chern-Simons theory on $X$ descend to theories on ordinary twistor space. Once on twistor space, compactifying along the...
I will describe shortly what the higher-spin charges are and why they are relevant from a holographic point of view. Besides, I will emphasize the recent result according to which they are realized as Noether charges in a non-linear regime.
In this work, we find the beta deformation states in the context of twistor string theory. For that, we make cohomological computations in the topological B-model defined on the projective space $\mathbb{CP}^{3|4}$. We identify the beta deformation states as elements of the BRST cohomology. We find that by first defining the beta deformation states as states leaving in a specific...
