Events at 402 Classroom Physics South, Campus

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Abstract: In de Sitter (dS), observers cannot be treated as separate from the rest of spacetime, and hence observables are inextricably linked to their observers. In this talk, we emphasize that observers must also be treated using QFT.  We then explore how well spaces of states and observables, each defined relative to a QFT observer, approximate standard non-gravitating QFT in a fixed … Read More

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Abstract: String theory has its origins based on the so-called dual resonance hypothesis which had only slender experimental support. This led to the discovery of the Veneziano amplitude which sums over poles in one channel or the other, unlike what we do in familiar quantum field theory. I will present a new representation of the Veneziano amplitude, arising from a … Read More

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Abstract: Axion-like particles and Dark Photons are two well-motivated candidates of wave-like dark matter and are the subject of many ongoing experimental searches. Many of these rely on resonance phenomena, either directly in the lab or indirectly in astrophysical environments. We will discuss how the Earth’s well-studied ionosphere exhibits features of both of these effects. The weakly-ionised plasma allows for resonant … Read More

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Abstract:  All black holes in AdS become unstable at a non-zero critical temperature, except if they are protected by supersymmetry. In the favored ground state, the black hole fragments into a a finite matter halo and a smaller remnant. In the dual CFT description, the instability is realized by two phases with distinct condensates that meet at a critical line … Read More

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Abstract: In this talk, I will discuss a class of many body chaotic models related to the Brownian Sachdev-Ye-Kitaev model. An emergent symmetry maps the quantum dynamics into a classical stochastic process. Thus we are able to study many dynamical properties at finite N on an arbitrary graph structure. This talk is mainly based on paper arxiv: 2308.11123, but it is … Read More

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Summary: $\alpha’$ corrections to near horizon dynamics of a Schwarzschild black hole in a large number of spacetime dimensions $D$ are governed by the worldsheet theory composed of the cigar CFT and the classical sigma model on the sphere at the horizon, along with a timelike-Liouville theory of central charge $26-D$. At leading order in weak string coupling, black hole thermodynamics … Read More

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We study the discovery potential of Z branching ratios due to contributions induced by the MSSM electroweak sector, assuming that the squarks and gluinos are heavy. Precision measurements at a future Z factory would yield sensitivity to MSSM that is complementary to direct searches at the LHC, provided that the systematic uncertainties can be reduced to a level comparable to … Read More

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Abstract Should we include a sum over wormhole topologies in the path integral of quantum gravity? While doing so has been very useful in the last few years, it also leads to features that are inconsistent with traditional holography, like the lack of factorization of the partition function on disconnected boundaries. In this talk, I will propose a systematic algorithm … Read More

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Abstract: It was recently understood that holographic BPS states can be divided into two categories: monotone and fortuitous. Various pieces of evidence suggest that monotone states correspond to horizonless microstate geometries, while fortuitous states are dual to supersymmetric black holes. In this talk, I will connect this classification to the fine-grained features of these states using concepts from quantum chaos. … Read More

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This is the first of two talks. I will give an overview on algebraic categorification of tensors products of type A quantum group representations emphasising the role of (categorified) skew Howe duality. The results are in principle not new, but the focus will be on explaining the advantages and disadvantages of the existing approaches. In particular I like to illustrate … Read More