25 citations · 222 across the 24 of their papers we have counts for
24 papers
Smooth metrics can hide thin shells
Justin C. Feng
In this note, I consider a class of metric tensors with smooth components that naively appear to describe dynamical wormholes with vanishing spacetime curvature. I point out that t…
Linearised conformal Einstein field equations
Justin Feng, Edgar Gasperin
The linearisation of a second-order formulation of the conformal Einstein field equations (CEFEs) in Generalised Harmonic Gauge (GHG), with trace-free matter is derived. The linear…
Shielding a charged black hole
Justin C. Feng, Sumanta Chakraborty, Vitor Cardoso
We describe a shielding mechanism for a charged black hole immersed in a background involving charged matter fields, solely arising from the Einstein-Maxwell field equations. In pa…
The good-bad-ugly system near spatial infinity on flat spacetime
Miguel Duarte, Justin Feng, Edgar Gasperin +1
A system of equations that serves as a model for the Einstein field equation in generalised harmonic gauge called the good-bad-ugly system is studied in the region close to null an…
Regularizing Dual-Frame Generalized Harmonic Gauge at Null Infinity
Miguel Duarte, Edgar Gasperín, Justin C. Feng +1
The dual-frame formalism leads to an approach to extend numerical relativity simulations in generalized harmonic gauge (GHG) all the way to null infinity. A major setback is that w…
Peeling in Generalized Harmonic Gauge
Miguel Duarte, Justin C. Feng, Edgar Gasperin +1
It is shown that a large class of systems of non-linear wave equations, based on the good-bad-ugly model, admit formal solutions with polyhomogeneous expansions near null infinity.…
Junction conditions and sharp gradients in generalized coupling theories
Justin C. Feng, Shinji Mukohyama, Sante Carloni
In this article, we develop the formalism for singular hypersurfaces and junction conditions in generalized coupling theories using a variational approach. We then employ this form…
Relativistic location algorithm in curved spacetime
Justin C. Feng, Filip Hejda, Sante Carloni
In this article, we describe and numerically implement a method for relativistic location in slightly curved but otherwise generic spacetimes. For terrestrial positioning in the co…
Weiss variation for general boundaries
Justin C. Feng, Sumanta Chakraborty
The Weiss variation of the Einstein-Hilbert action with an appropriate boundary term has been studied for general boundary surfaces; the boundary surfaces can be spacelike, timelik…
Self-collision of a portal wormhole
Justin C. Feng, José P. S. Lemos, Richard A. Matzner
We consider the self-collision of portals in classical general relativity. Portals are wormholes supported by a single loop of negative mass cosmic string, and being wormholes, por…
High Order Asymptotic Expansions of a Good-Bad-Ugly Wave Equation
Miguel Duarte, Justin Feng, Edgar Gasperin +1
A heuristic method to find asymptotic solutions to a system of non-linear wave equations near null infinity is proposed. The non-linearities in this model, dubbed good-bad-ugly, ar…
Perturbations of the almost Killing equation and their implications
Sumanta Chakraborty, Justin C. Feng
Killing vectors play a crucial role in characterizing the symmetries of a given spacetime. However, realistic astrophysical systems are in most cases only approximately symmetric.…
Minimal exponential measure model in the post-Newtonian limit
Justin C. Feng, Shinji Mukohyama, Sante Carloni
We examine the post-Newtonian limit of the minimal exponential measure (MEMe) model presented in [J. C. Feng, S. Carloni, Phys. Rev. D 101, 064002 (2020)] using an extension of the…
On Beltrami states near black hole event horizon
Chinmoy Bhattacharjee, Justin C. Feng
In this article, we study Beltrami equilibria for plasmas in near the horizon of a spinning black hole, and develop a framework for constructing the magnetic field profile in the n…
Note on gravity at the boundary of an AdS vacuum
Justin C. Feng
In this note, I describe an attempt to construct a phenomenological gravitational model at the boundary of the AdS manifold from the variation of boundary terms in the gravitationa…
Almost-Killing equation: Stability, hyperbolicity, and black hole Gauss law
Justin C. Feng, Edgar Gasperín, Jarrod L. Williams
We examine the Hamiltonian formulation and hyperbolicity of the almost-Killing equation (AKE). We find that for all but one parameter choice, the Hamiltonian is unbounded, and in s…
A new laser-ranged satellite for General Relativity and space geodesy: IV. Thermal drag and the LARES 2 space experiment
Ignazio Ciufolini, Richard A. Matzner, Justin C. Feng +6
In three previous papers we presented the LARES 2 space experiment aimed at a very accurate test of frame-dragging and at other tests of fundamental physics and measurements of spa…
New class of generalized coupling theories
Justin C. Feng, Sante Carloni
We propose a new class of gravity theories which are characterized by a nontrivial coupling between the gravitational metric and matter mediated by an auxiliary rank-2 tensor. The…
Black hole in a superconducting plasma
Chinmoy Bhattacharjee, Justin C. Feng, S. M. Mahajan
The generalized vortical formalism provides an electrodynamic description for superconducting states---in the generalized vortical formalism, a superconducting state may be defined…
Some globally conserved currents from generalized Killing vectors and scalar test fields
Justin C. Feng
In this article, I discuss the construction of some globally conserved currents that one can construct in the absence of a Killing vector. One is based on the Komar current, which…
PoMiN: A Post-Minkowskian -Body Solver
Justin Feng, Mark Baumann, Bryton Hall +3
In this paper, we introduce PoMiN, a lightweight -body code based on the post-Minkowskian -body Hamiltonian of Ledvinka et. al., which includes general relativistic effects u…
Volume average regularization for the Wheeler-DeWitt equation
Justin C. Feng
In this article, I present a volume average regularization for the second functional derivative operator that appears in the metric-basis Wheeler-DeWitt equation. Naively, the seco…
From path integrals to the Wheeler-DeWitt equation: Time evolution in spacetimes with a spatial boundary
Justin C. Feng, Richard A. Matzner
We reexamine the relationship between the path integral and canonical formulation of quantum general relativity. In particular, we present a formal derivation of the Wheeler-DeWitt…
The Weiss Variation of the Gravitational Action
Justin C. Feng, Richard A. Matzner
The Weiss variational principle in mechanics and classical field theory is a variational principle which allows displacements of the boundary. We review the Weiss variation in mech…