scholarly journals Gravitational breathing memory and dual symmetries

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ali Seraj
Keyword(s):  
General Relativity ◽  
Gauge Theory ◽  
Scalar Field ◽  
Memory Effects ◽  
Balance Equations ◽  
Symmetry Principle ◽  
Dual Formulation ◽  
Physical Role ◽  
Asymptotic Symmetries

Abstract Brans-Dicke theory contains an additional propagating mode which causes homogeneous expansion and contraction of test bodies in transverse directions. This “breathing” mode is associated with novel memory effects in addition to those of general relativity. Standard tensor mode memories are related to a symmetry principle: they are determined by the balance equations corresponding to the BMS symmetries. In this paper, we show that the leading and subleading breathing memory effects are determined by the balance equations associated with the leading and “overleading” asymptotic symmetries of a dual formulation of the scalar field in terms of a two-form gauge field. The memory effect causes a transition in the vacuum of the dual gauge theory. These results highlight the significance of dual charges and the physical role of overleading asymptotic symmetries.

scholarly journals Conformally soft fermions

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Yorgo Pano ◽  
Sabrina Pasterski ◽  
Andrea Puhm
Keyword(s):  
Gauge Theory ◽  
Inner Product ◽  
Conformal Dimension ◽  
Infinite Dimensional ◽  
Primary Operator ◽  
Left And Right ◽  
Symmetry Generators ◽  
Goldstone Modes ◽  
Asymptotic Symmetries

Abstract Celestial diamonds encode the global conformal multiplets of the conformally soft sector, elucidating the role of soft theorems, symmetry generators and Goldstone modes. Upon adding supersymmetry they stack into a pyramid. Here we treat the soft charges associated to the fermionic layers that tie this structure together. This extends the analysis of conformally soft currents for photons and gravitons which have been shown to generate asymptotic symmetries in gauge theory and gravity to infinite-dimensional fermionic symmetries. We construct fermionic charge operators in 2D celestial CFT from a suitable inner product between 4D bulk field operators and spin s = $$ \frac{1}{2} $$ 1 2 and $$ \frac{3}{2} $$ 3 2 conformal primary wavefunctions with definite SL(2, ℂ) conformal dimension ∆ and spin J where |J| ≤ s. The generator for large supersymmetry transformations is identified as the conformally soft gravitino primary operator with ∆ = $$ \frac{1}{2} $$ 1 2 and its shadow with ∆ = $$ \frac{3}{2} $$ 3 2 which form the left and right corners of the celestial gravitino diamond. We continue this analysis to the subleading soft gravitino and soft photino which are captured by degenerate celestial diamonds. Despite the absence of a gauge symmetry in these cases, they give rise to conformally soft factorization theorems in celestial amplitudes and complete the celestial pyramid.

scholarly journals New physical parameterizations of monopole solutions in five-dimensional general relativity and the role of negative scalar field energy in vacuum solutions

2021 ◽  
Author(s):  
Y. Balytskyi ◽  
D. Hoyer ◽  
A. O. Pinchuk ◽  
L. L. Williams
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Energy Density ◽  
Electric Field ◽  
Electric Charge ◽  
Field Energy ◽  
Scalar Charge ◽  
Field Energy Density ◽  
Vacuum Solutions

Abstract Novel parameterizations are presented for monopole solutions to the static, spherically-symmetric vacuum field equations of five-dimensional general relativity. First proposed by Kaluza, 5D general relativity unites gravity and classical electromagnetism with a scalar field. These monopoles correspond to bodies carrying mass, electric charge, and scalar charge. The new parameterizations provide physical insight into the nature of electric charge and scalar field energy. The Reissner-Nordstr\"om limit is compared with alternate physical interpretations of the solution parameters. The new parameterizations explore the role of scalar field energy and the relation of electric charge to scalar charge. The Kaluza vacuum equations imply the scalar field energy density is the negative of the electric field energy density for all known solutions, so the total electric and scalar field energy of the monopole is zero. The vanishing of the total electric and scalar field energy density for vacuum solutions seems to imply the scalar field can be understood as a negative-energy foundation on which the electric field is built.

SPATIALLY FLAT FRW MODELS WITH A NONMINIMALLY COUPLED GHOST SCALAR FIELD AND PERFECT FLUID IN EINSTEIN–CARTAN THEORY

2012 ◽  
Vol 21 (01) ◽  
pp. 1250001 ◽  
Author(s):  
A. M. GALIAKHMETOV
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Perfect Fluid ◽  
Analogous Problem ◽  
General Solutions ◽  
Cartan Theory ◽  
Frw Models ◽  
Ghost Scalar Field

Exact general solutions to the Einstein–Cartan equations are obtained for spatially flat Friedmann cosmologies with a nonminimally coupled ghost scalar field and perfect fluid. It is shown that both singular and bouncing models are possible. An analogous problem is investigated in general relativity. Some effects of torsion are elucidated. The role of perfect fluid in the Einstein–Cartan cosmology is discussed.

scholarly journals Asymptotically Flat Boundary Conditions for the U(1)3 Model for Euclidean Quantum Gravity

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 68
Author(s):  
Sepideh Bakhoda ◽  
Hossein Shojaie ◽  
Thomas Thiemann
Keyword(s):  
General Relativity ◽  
Gauge Theory ◽  
Quantum Gravity ◽  
Boundary Conditions ◽  
Crucial Role ◽  
Test Laboratory ◽  
Asymptotically Flat ◽  
Generally Covariant ◽  
Asymptotic Symmetries

A generally covariant U(1)3 gauge theory describing the GN→0 limit of Euclidean general relativity is an interesting test laboratory for general relativity, specially because the algebra of the Hamiltonian and diffeomorphism constraints of this limit is isomorphic to the algebra of the corresponding constraints in general relativity. In the present work, we the study boundary conditions and asymptotic symmetries of the U(1)3 model and show that while asymptotic spacetime translations admit well-defined generators, boosts and rotations do not. Comparing with Euclidean general relativity, one finds that the non-Abelian part of the SU(2) Gauss constraint, which is absent in the U(1)3 model, plays a crucial role in obtaining boost and rotation generators.

TOPOLOGICAL DEFECTS AND GRAVITATIONAL FORCES IN BRANS–DICKE THEORY

2001 ◽  
Vol 16 (20) ◽  
pp. 1297-1301 ◽  
Author(s):  
A. BARROS ◽  
C. ROMERO
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Topological Defects ◽  
Gravitational Forces ◽  
Theory Of Gravity

The nature of gravitational forces exerted by topological defects on surrounding matter in the frame of Brans–Dicke theory of gravity (BD) is investigated. Comparison is made with the corresponding cases in General Relativity (GR). The role of the scalar field as a weakener agent of the strength of gravitational forces due to pressure terms is discussed.

scholarly journals Brans-Dicke theory in Bondi-Sachs form: Asymptotically flat solutions, asymptotic symmetries, and gravitational-wave memory effects

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Shammi Tahura ◽  
David A. Nichols ◽  
Alexander Saffer ◽  
Leo C. Stein ◽  
Kent Yagi
Keyword(s):  
Gravitational Wave ◽  
Memory Effects ◽  
Asymptotically Flat ◽  
Asymptotic Symmetries

scholarly journals Does general relativity highlight necessary connections in nature?

Synthese ◽  
2021 ◽  
Author(s):  
Antonio Vassallo
Keyword(s):  
General Relativity ◽  
Laws Of Nature ◽  
Coupling Mechanism ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Bianchi Identities ◽  
Physical Role ◽  
General Relativistic ◽  
Differential Relations ◽  
Necessary Connections

AbstractThe dynamics of general relativity is encoded in a set of ten differential equations, the so-called Einstein field equations. It is usually believed that Einstein’s equations represent a physical law describing the coupling of spacetime with material fields. However, just six of these equations actually describe the coupling mechanism: the remaining four represent a set of differential relations known as Bianchi identities. The paper discusses the physical role that the Bianchi identities play in general relativity, and investigates whether these identities—qua part of a physical law—highlight some kind of a posteriori necessity in a Kripkean sense. The inquiry shows that general relativistic physics has an interesting bearing on the debate about the metaphysics of the laws of nature.

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