Event Category: String Seminar

String Seminar:
Tuesdays at 3:40pm on campus

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It is generally expected that during the black hole evaporation process, correlations within the Hawking radiation first start to grow at a time scale called the Page time. The information of a diary thrown into the black hole is also expected to become accessible from the radiation at the Page time. These expectations are based on averages over Haar-random pure … Read More

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Abstract: The vacuum-to-vacuum genus-zero string graph is expected to be related to the thermodynamics of the target spacetime, and is thus an interesting quantity to compute. However, this quantity is very confusing in critical string theory. In order to understand it better, we compute the vacuum sphere partition function in noncritical string theory in the semiclassical limit, where a saddle point approximation … Read More

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Abstract: Does gravity constrain computation? We study this question usingthe AdS/CFT correspondence, where computation in the presence ofgravity can be related to non-gravitational physics in the boundary theory. In AdS/CFT, computations which happen locally in the bulk areimplemented in a particular non-local form in the boundary, which ingeneral requires distributed entanglement. In more detail, we recall thatfor a large class … Read More

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Abstract: It has been proposed in the literature that the volume of Einstein–Rosen bridge is equal to complexity of state preparation (”Complexity=Volume” conjecture). Taking this statement outside the horizon, one might be tempted to propose ”Complexity=Time” correspondence. In this talk I argue that in a blockchain protocol, which is the foundation of all modern cryptocurrencies, time is emergent and it … Read More

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Abstract: I will discuss work in progress with Shenker, Stanford, Yang, and Yao focused on understanding certain universal aspects of spacetime wormholes at late times. In particular, we focus on the late time behavior of the spectral form factor, making an analogy with the explanation of these features in semiclassical periodic orbit theory. For semiclassical periodic orbits, the spectral form … Read More

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Abstract: I will discuss ongoing work on studying operator algebras in semiclassical gravity. In AdS/CFT, the large N limit of single-trace operators in the boundary CFT results in a type 3 von Neumann algebra. Including 1/N corrections promotes the algebra to type 2, which allows the von Neumann entropy to be defined and calculated. I will describe how this works … Read More

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Abstract: The Distance Conjecture holds that any infinite-distance limit in the scalar field moduli space of a consistent theory of quantum gravity must be accompanied by a tower of light particles whose masses scale exponentially with proper field distance $||\phi||$ as $m \sim \exp(- \lambda ||\phi||)$, where $\lambda$ is order-one in Planck units. While the evidence for this conjecture is formidable, … Read More

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Motivated by properties of tensor networks, we conjecture that an arbitrary gravitating region a can be assigned a generalized entanglement wedge E⊃a, such that quasi-local operators in E have a holographic representation in the full algebra generated by quasi-local operators in a. The universe need not be asymptotically flat or AdS, and a need not be asymptotic or weakly gravitating.  On a static Cauchy surface Σ, we propose that E is the … Read More