Events at 402 Classroom Physics South Hall, Campus

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Abstract:  Starting from canonical quantization, one can derive the path integral formulation and show that the resulting measure differs from the standard ultralocal one. This difference becomes particularly significant in asymptotically AdS spacetimes, where it leads to a distinct functional space for fluctuations. We will argue that this canonical measure helps resolve several conceptual issues, including the choice of admissible boundary … Read More

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Abstract:——–The gravitational path integral suggests a striking result: the Hilbert space of closed universes in each superselection sector, a so-called alpha-sector, is one-dimensional. We develop an abstract formalism encapsulating recent proposals that modify the gravitational path integral in the presence of observers and allow larger Hilbert spaces to be associated with closed universes. Our formalism regards the gravitational path integral … Read More

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Abstract: I will present two examples of how cosmological lattice simulations can be used to study the properties of QCD axion dark matter in the early Universe. First, the phenomenology of three variants of the Axion Misalignment mechanism (Standard, Kinetic, and Large Misalignment) will be discussed. It can be shown that non-linearities and the phenomenon of fragmentation depend not only … Read More

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Abstract:  This is a series of two lectures on categorifying quantum group U_q(g) using Fukaya categories proposed by Mina Aganagic. In the first lecture, we will give an introduction to the theory, focusing on the geometric setup, basic calculations and connection to representation theory; in the second lecture we will discuss the TQFT structures underlying our theory, proposing the definition … Read More

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Abstract: Massive Compact Halo Objects (MACHOs) remain a viable dark matter candidate that can be tested through their dynamical effects on stellar systems. In this talk, I will present how dynamical heating of stars in ultrafaint dwarf (UFD) galaxies provides powerful constraints on MACHOs across a broad mass range. I will demonstrate the robustness of these bounds by conducting a … Read More

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Abstract: This is the 2nd part of a series of two talks on categorification of quantum group U_q(g) using Fukaya categories proposed by Mina Aganagic. In the first talk, we will give an introduction to the theory, focusing on the geometric setup, basic calculations and connection to representation theory; in the second talk we will discuss the TQFT structures underlying … Read More

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Abstract: For any well-behaved link homology theory for links in the 3-sphere, Morrison–Walker–Wedrich defined an invariant for smooth 4-manifolds called skein lasagna modules, which can be viewed as an upgrade of the input link homology theory. We review the definition and investigate some formal properties of the invariant. We also introduce a few variations of the invariant. In the case where … Read More

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Abstract:In this talk, we study conformal field theories with a global U(1) symmetry on ℝ × S^{d−1} in the regime of large charge and large angular momentum. The lowest-energy state is a rotating superfluid vortex solution that interpolates between the large-charge superfluid at zero angular momentum and a Regge-limit state at large angular momentum. The stress tensor and U(1) current … Read More

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Abstract: A magnetically levitated mass couples to gravity and can act as an effective gravitational wave detector. In this talk, we will discuss show how a superconducting sphere levitated in a quadrupolar magnetic field, when excited by a gravitational wave, can produce magnetic field fluctuations that can be read out using a flux tunable microwave resonator, thus serving as a … Read More