Past Events

  • 2019 Oct 15

    BHI Colloquium

    1:30pm to 2:30pm

    Location: 

    BHI Meeting Room

    Elena Giorgi (Princeton University)

    Title: On the stability of black holes in classical GR

    Abstract: The stability of black holes is one of the main open problems in GR, and fits in the broader picture of the "final state conjecture", according to which all asymptotically flat initial data for the
    Einstein equation eventually evolve into a finite number of Kerr solutions. We give an overview of the problem of stability of solutions to the Einstein equation, starting from the Minkowski space to the...

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  • 2019 Oct 08

    BHI Colloquium

    1:30pm to 2:30pm

    Location: 

    BHI Meeting Room

    Kento Yagi (Virginia University)

    Title: Theory-agnostic Tests of Gravity with Gravitational Waves

    Abstract: Compact binary merger events recently discovered by the LIGO and Virgo Collaboration offer us excellent testbeds for probing fundamental physics. In this talk, I will focus on two theory-agnostic ways of probing gravity in the strong- and dynamical-field regime. I will first review the current status with the observed binary black hole merger events. I will then describe how such tests will improve in...

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  • 2019 Oct 01

    BHI Colloquium

    1:30pm to 2:30pm

    Location: 

    BHI Meeting Room

    JB Manchak (Irvine)

    Title: Is the Universe As Large As It Can Be?

    Abstract: Within the context of general relativity, a spacetime is counted as inextendible if it is 'as large as possible' in the appropriate sense. It is widely accepted that inextendibility is a "reasonable physical condition to be imposed on models of the universe" (Geroch 1970). Here, in a variety of ways, we register some skepticism with respect to this position.

    Selma de Mink (Harvard)...

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  • 2019 Sep 24

    BHI Colloquium

    1:30pm to 2:30pm

    Location: 

    BHI Meeting Room

    Tejaswi Venumadhav (Princeton University)

    Title: A new independent analysis of LIGO data: methods and results

    Abstract: The Advanced LIGO and VIRGO observatories detected several gravitational-wave events in their first and second observing runs from 2015 to 2017. The detections were only possible due to sophisticated analyses of noisy strain data that were historically conducted within the collaboration. Recently, we developed an entirely independent analysis of LIGO data that improved its reach by...

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  • 2019 Sep 17

    BHI Colloquium

    1:30pm to 2:30pm

    Location: 

    BHI Meeting Room

    Dr. Vivienne Baldassare (Yale University)

    Title: Searching for active galactic nuclei in low-mass galaxies with optical photometric variability

    Abstract: The population of massive black holes (BHs) at the centers of nearby low-mass galaxies provides some of the best observational constraints on the masses of “black hole seeds” at high redshift. Furthermore, while BHs are ubiquitous and well-studied in Milky Way-sized and larger galaxies, relatively little is known about the population and properties of BHs in...

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  • 2019 Sep 10

    BHI Colloquium

    1:30pm to 2:30pm

    Location: 

    BHI Meeting Room

    Linear gravity in Schwarzschild spacetime under the harmonic gauge.

    Dr. Pei-Ken Hung

    In this talk, we will discuss the linearized Einstein equation under the harmonic gauge, which is equivalent to a hyperbolic system for symmetric 2-tensors. We will begin with an overview of the vector field method for scalar wave equations. Based on this technique, we study the tensorial wave equation for 1-forms in the Schwarzschild spacetime and, as an application, the linearized Einstein equation. This is a...

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  • 2019 May 07

    Martin LeSourd (University of Oxford) and Andrew Chael (CFA-Harvard University)

    1:30pm to 2:30pm

    Location: 

    BHI conference Room: 20 Garden Street, Cambridge (Lunch will be served at 1:00 pm)

    Title: 'Bartnik's splitting conjecture and results in its favor'

    Abstract:  Singularity theorems suggest that many spacetimes are  geodesically incomplete. One way to test this idea is to show that geodesically complete spacetimes have to be special in some sense. In 1982 Yau conjectured a statement of this kind (which was proven in the 80s) and in 1988 Bartnik made the stronger and still open conjecture that spacetimes with compact Cauchy surfaces that satisfy the strongenergy condition must be...

    Read more about Martin LeSourd (University of Oxford) and Andrew Chael (CFA-Harvard University)
  • 2019 Apr 30

    David Garfinkle (Oakland University) and Porter Williams (USC)

    1:30pm to 3:30pm

    Location: 

    BHI conference Room: 20 Garden Street, Cambridge (Lunch will be served at 1:00 pm)

    David Garfinkle

    Numerical Simulations of Spacetime Singularities

    Spacetime singularities occur at the Big Bang and in black hole interiors. This talk describes the use of computer simulations to understand the nature of spacetime singularities. Both the vacuum Einstein equations and matter models are treated. Most of the simulations are done for the case of closed, inhomogeneous cosmologies. In this case, the simulations show that the BKL approximation, in which time derivatives are more important than space derivatives, is justified....

    Read more about David Garfinkle (Oakland University) and Porter Williams (USC)
  • 2019 Apr 23

    Michel Janssen (University of Minnesota) and Kiraniyot Gill (Harvard CFA)

    1:30pm to 2:30pm

    Location: 

    BHI conference Room: 20 Garden Street, Cambridge (Lunch will be served at 1:00 pm)

    Michel Janssen (University of Minnesota

    Title:  Arch and scaffold: How Einstein found his field equations

    Abstract: In his later years, Einstein often claimed that he had obtained the field equations of general relativity by choosing the mathematically most natural candidate. His writings during the period in which he developed general relativity tell a different story.

    Based on an article co-authored with Jürgen Renn in Physics Today in November 2015 to mark the centenary of the first publication of the Einstein field...

    Read more about Michel Janssen (University of Minnesota) and Kiraniyot Gill (Harvard CFA)
  • 2019 Apr 16

    Glenn Barnich (Free University of Brussels & International Solvay Institutes) & Ven Chandrasekaran (UC Berkeley)

    1:30pm to 2:30pm

    Location: 

    BHI conference Room: 20 Garden Street, Cambridge (Lunch will be served at 1:00 pm)

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