Today

  • Resolving memory in numerical relativity, and fixing BMS frames for modeling

    https://youtu.be/zG4xkY8JI1A General Relativity Seminar Speaker: Leo Stein (Mississippi) Title: Resolving memory in numerical relativity, and fixing BMS frames for modeling Abstract: Numerical relativity waveforms serve as ground truth for detection and parameter estimation of binary black hole mergers. Most NR waveforms to date miss memory effects, as they were extracted from simulations using an approximation called extrapolation. I […]

  • Fluid stabilization in slowly expanding cosmological spacetime

    Hybrid - G10

    https://youtu.be/SCIi6R_uTZM General Relativity Seminar Speaker: David Fajman (Vienna) Title: Fluid stabilization in slowly expanding cosmological spacetime Abstract: Relativistic fluids are known to form shocks during their evolution from near-homogeneous initial data. In expanding spacetimes, shock formation is suppressed, if the expansion is sufficiently strong. We refer to this effect as fluid stabilization. The occurrence of this phenomenon depends […]

  • Quasi-Local Mass in a Binary Black Hole Merger

    Virtual

    https://youtu.be/cboxkchYFUk General Relativity Seminar Speaker: Daniel Kolb (Max Planck Institute) Title: Quasi-Local Mass in a Binary Black Hole Merger Abstract: One of the major open problems in classical general relativity is how one should define the mass of a finite region of space. In this talk, we will investigate a promising definition proposed by Wang and […]

  • Remarkable symmetries of rotating black holes

    https://youtu.be/cSgyLwg0v00 General Relativity Seminar Speaker: David Kubiznak (Charles University) Title: Remarkable symmetries of rotating black holes Abstract: It is well known that the Kerr geometry admits a non-trivial Killing tensor and its 'square root' known as the Killing-Yano tensor. These two objects stand behind Carter's constant of geodesic motion as well as allow for separability of test […]

  • The Feynman propagator and self-adjointness

    Virtual

    https://youtu.be/xTnSasVv4_0 General Relativity Seminar Speaker: Andras Vasy (Stanford) Title: The Feynman propagator and self-adjointness Abstract: In this talk I will discuss the Feynman and anti-Feynman inverses for wave operators on certain Lorentzian manifolds; these are two inverses which from a microlocal analysis perspective are more natural than the standard causal (advanced/retarded) ones. For instance, for the spectral family […]

  • General Relativity Seminar

    A quasi-local mass in general relativity

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    https://youtu.be/hmRFX1Js6IA General Relativity Seminar Speaker: Aghil Alaee, Clark University Title: A quasi-local mass in general relativity Abstract: In this talk, we define a new gauge-independent quasi-local mass and energy with respect to the Minkowski spacetime. In contrast to other quasi-local masses, this new quasi-local mass/energy has a quasi-local proof of positivity. This positivity property is for spacelike surfaces with any topology.  Moreover, we show […]

  • General Relativity Seminar

    Noncompact n-dimensional Einstein spaces as attractors for the Einstein flow

    Virtual

    General Relativity Seminar Speaker: Jinhua Wang, Xiamen University Title: Noncompact n-dimensional Einstein spaces as attractors for the Einstein flow Abstract: We prove that along with the Einstein flow, any small perturbations of an $n$($n\geq4$)-dimensional, non-compact negative Einstein space with some "non-positive Weyl tensor" lead to a unique and global solution, and the solution will be attracted to […]

  • General Relativity Seminar

    Characteristic Initial Value Problem for the 3D Compressible Euler Equations

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    General Relativity Seminar Speaker: Sifan Yu, NUS Title: Characteristic Initial Value Problem for the 3D Compressible Euler Equations Abstract: We present the first result for the characteristic initial value problem of the compressible Euler equations in three space dimensions without any symmetry assumption. We allow presence of vorticity and consider any equation of state. Compared […]

  • General Relativity Seminar

    Asymptotic decay for defocusing semilinear wave equations on Schwarzschild spacetimes

    Virtual

    General Relativity Seminar Speaker: He Mei, Shenzhen University Title: Asymptotic decay for defocusing semilinear wave equations on Schwarzschild spacetimes Abstract: In this talk, I will present a work on the long time dynamics of solutions to the defocusing semilinear wave equations on the Schwarzschild black hole spacetimes. For sufficiently smooth and localized initial data, we show that the […]

  • General Relativity Seminar

    On Axially Symmetric Perturbations of Kerr Black Hole Spacetimes

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    https://youtu.be/G98ywTI82fg General Relativity Seminar Speaker: Nishanth Gudapati, Clark University Title: On Axially Symmetric Perturbations of Kerr Black Hole Spacetimes Abstract: The Kerr black hole stability problem is an important open problem in general relativity. In this talk, I will focus on the role of energy methods in the axisymmetric stability of Kerr black hole spacetimes. […]

  • General Relativity Seminar

    High order WENO finite difference scheme  for Einstein-Yang-Mills equations

    Virtual

    General Relativity Seminar Speaker: Yuewen Chen, Tsinghua University Title: High order WENO finite difference scheme  for Einstein-Yang-Mills equations Abstract: In this talk, we will show the convergence analysis of the first-order finite difference scheme for static spherically symmetric $SU(2)$ Einstein-Yang-Mills (EYM) equations. We also construct a new WENO scheme for EYM.

  • General Relativity Seminar

    Scattering Rigidity Problem

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    General Relativity Seminar Speaker: Jin Jia, Hunan University Title: Scattering Rigidity Problem Abstract: If the asymptotic behavior of a solution to a nonlinear equation is the same as that of a solution to its linearized equation, it is called a scattering solution. Scattering phenomena are widely observed near steady-state solutions of various mathematical physics equations, […]