NYGR Seminar
New York General Relativity Seminar
We meet 2-3 times per semester most semesters alternating between Columbia, Stony Brook and the CUNY Graduate Center.
Current organizers: Marcus Khuri, Dan Lee, Henri Roesch, Christina Sormani, and Mu-Tao Wang.
Past organizers include Mike Anderson, Po-Ning Chen, Sergiu Klainerman, and Lan-Hsuan Huang.
Feb 7, 2019 at Columbia
Speaker Pengyu Le
Title: TBA
Abstract: TBA
Speaker Christos Mantoulidis
Title: TBA
Abstract: TBA
Nov 29, 2018 at CUNYGC in 3305:
Hyun Chul Jang (U Conn) 3:00-4:00 pm
Title: Rigidity conjecture for asymptotically hyperbolic spaces with zero mass
Abstract: Recently, Huang and Lee proved the rigidity of the spacetime positive mass theorem by using a variational approach. Motivated by this work, we prove that assuming the nonnegativity of the mass of asymptotically hyperbolic Riemannian manifolds (without boundary) with scalar curvature greater than or equal to -n(n-1), the mass is zero if and only if the manifold is isometric to the standard hyperbolic space. By a variational approach, we first prove the existence of a static potential for AH manifolds with zero mass (in fact, AH manifolds with minimal mass), and then conclude the proof by using the certain integral identity which has been discovered first by Wang. Furthermore, by using this integral identity, we prove that for a static, asymptotically locally hyperbolic manifold with a certain boundary condition, the mass is zero if and only if the manifold is isometric to (some portion of) the reference manifold to which it is asymptotic. This is based on the joint work with Lan-Hsuan Huang and Daniel Martin.
Jeff Jauregui (Union College) 4:30-5:30 pm
Title: Semicontinuity of total mass and low-regularity convergence in general relativity
Abstract: In general relativity, the ADM mass captures the total mass of an asymptotically flat spacelike hypersurface in a spacetime. Motivated by the conjectured near-rigidity of the positive mass theorem and by Bartnik's minimal mass extension conjecture, it is natural to study the interaction between the ADM mass and low-regularity convergence. We will discuss joint work with Dan Lee on establishing the lower semicontinuity of ADM mass for pointed C^0 convergence and Sormani--Wenger intrinsic flat convergence, which has shown promise for low-regularity problems in general relativity. We will make use of Huisken's isoperimetric mass concept.
Oct. 4, 2018 at Stony Brook:
Eric Woolgar (U Alberta) in Room 102 of SCGP 3:00-4:00 pm
Title: Bakry-Emery curvature-dimension conditions in relativity
Abstract: Many important theorems in Riemannian geometry depend on a lower bound for the Ricci curvature. In general relativity, \emph{energy conditions} play a similar role by providing lower bounds for components of Ricci curvature. In recent years, it has been realized that these lower bounds need only hold up to a Hessian term, or more generally a Lie derivative term. I will discuss new applications to general relativity that have arisen from this realization, including generalized singularity and splitting theorems and new results that constrain extreme black hole horizon topology. This talk is based on joint work with Greg Galloway, and with Marcus Khuri and William Wylie.
Siyuan Lu (Rutgers) in Room 102 of SCGP 5:00-6:00 pm
Title: On a localized Riemannian Penrose inequality
Abstract: For a bounded manifold with nonnegative scalar curvature, the Brown-York quasi-local mass is nonnegative and equals to 0 iff it's a domain in Euclidean space by fundamental results of Shi and Tam. Moreover, it is shown that the inequality is equivalent to Positive mass theorem. We consider the general setting that the bounded manifold allows a horizon. We establish a localized Riemannian Penrose inequality and prove that the equality holds iff it's a domain in Schwarzschild manifold. Similar to the Shi-Tam case, the inequality is equivalent to Riemannian Penrose inequality. This is based on joint works with P. Miao.
No meetings in 2017-2018 except SCGP Mass in GR Workshop and CUNY GR Workshop
Previous meetings (this list may be incomplete):
April 14, 2017 at Columbia
Jeremie Szeftel
Title: Remarks on the nonlinear stability of Schwarzschild
Pei-Ken Hung and Jordan Keller
Title: Linear stability of Schwarzschild spacetime
Oct. 21, 2016 at Columbia:
Abhay Ashtekar (IGCP at Penn State)
Title: Asymptotically deSitter Spacetimes and positivity of the Bondi mass
Henri Roesch (Duke)
Title: Proof of a Null Penrose Conjecture using a new Quasi-local Mass.
March 24, 2016 at CUNY
Chen-Yun Lin (U Toronto)
Title: Estimating the Bartnik Mass
Iva Stavrov (Lewis and Clark)
Title: Shear Free Conditions on Initial Data Sets
May 8, 2015 at Columbia
Sergio Dain
Title: Geometrical inequalities for black holes and bodies
Yakov Shlapentokh-Rothman
Title: Stability and Instability of Scalar Fields on Kerr Spacetimes
Dec 12, 2014 at Stony Brook
Lydia Bieri
Title: Analysis of Radiation for the Einstein and the Maxwell Equations
Xinliang An
Title: Formation of Trapped Surfaces in General Relativity
Oct 10, 2014 at CUNY
Robert Wald
Title: Dynamic and Thermodynamic Stability of Black Holes and Black Branes
Iva Stavrov
Title: Hyperboloidal initial data for the Einstein evolution equations and the shear-free condition
Philippe LeFloch
Title: Weakly regular spacetimes with T2 symmetry
Sept 19 2014 at Columbia
Steve Liebling
Title: On the nonlinearly stability of AdS
Frans Pretorius
Title: The Instability of 5-dimensional black strings
Mar 7, 2014 at Stony Brook
Spyros Alexakis
Title: A reconstruction of waves from their emitted radiation and the final states of space-times.
Mu-Tao Wang
Title: On the center of mass in general relativity
Feb 7, 2014 at Columbia
Robert Wald
Title: Dynamic and Thermodynamic Stability of Black Holes and Black Branes
Piotr Chrusciel
Title: The mass of light cone
Speakers in 2013 included:
Hugh Bray
Po-Ning Chen
Sergio Kleinerman
Igor Rodnianski
Mihalis Dafermos
Pengzi Miao
Stefanos Aretakis
Greg Galloway
Jim Isenberg