Matter coupling in Minimal Massive 3D Gravity and spinor-matter interactions in exterior algebra formalism

In this work, by employing the exterior algebra formalism, we study the matter coupling in Minimal Massive 3D Gravity (MMG) by first considering that the matter Lagrangian is connection-independent and then considering that the matter coupling is connection-dependent. The matter coupling in MMG has been previously investigated in the work \cite{arvanitakis_2} in tensorial notation where the matter Lagrangian is considered to be connection-independent. In the first part of the present paper, we revisit the connection-independent matter coupling by using the language of differential forms. We derive the MMG field equation and construct the related source 2-form. We also obtain the consistency relation within this formalism. Next, we examine the case where the matter Lagrangian is connection-dependent. In particular, we concentrate on the spinor-matter coupling and obtain the MMG field equation by explicitly constructing the source term. We also get the consistency relation that the source term should satisfy in order that spinor-matter coupled MMG equation be consistent.

3D gravity in a box

The quantization of pure 3D gravity with Dirichlet boundary conditions on a finite boundary is of interest both as a model of quantum gravity in which one can compute quantities which are ``more local" than S-matrices or asymptotic boundary correlators, and for its proposed holographic duality to T\overline{T}TT¯-deformed CFTs. In this work we apply covariant phase space methods to deduce the Poisson bracket algebra of boundary observables. The result is a one-parameter nonlinear deformation of the usual Virasoro algebra of asymptotically AdS_33 gravity. This algebra should be obeyed by the stress tensor in any T\overline{T}TT¯-deformed holographic CFT. We next initiate quantization of this system within the general framework of coadjoint orbits, obtaining — in perturbation theory — a deformed version of the Alekseev-Shatashvili symplectic form and its associated geometric action. The resulting energy spectrum is consistent with the expected spectrum of T\overline{T}TT¯-deformed theories, although we only carry out the explicit comparison to \mathcal{O}(1/\sqrt{c})𝒪(1/c) in the 1/c1/c expansion.

The mass of a Lifshitz black hole

It is well known that massive 3D gravity admits solutions that describe Lifshitz black holes as those considered in non-relativistic holography. However, the determination of the mass of such black holes remained unclear as many different results were reported in the literature presenting discrepancies. Here, by using a robust method that permits to tackle the problem in the strong field regime, we determine the correct mass of the Lifshitz black hole of the higher-derivative massive gravity and compare it with other results obtained by different methods. Positivity of the mass spectrum demands an odd normalization of the gravity action. In spite of this fact, the result turns out to be consistent with computations inspired in holography.

3d gravity in Bondi-Weyl gauge: charges, corners, and integrability

We introduce a new gauge and solution space for three-dimensional gravity. As its name Bondi-Weyl suggests, it leads to non-trivial Weyl charges, and uses Bondi-like coordinates to allow for an arbitrary cosmological constant and therefore spacetimes which are asymptotically locally (A)dS or flat. We explain how integrability requires a choice of integrable slicing and also the introduction of a corner term. After discussing the holographic renormalization of the action and of the symplectic potential, we show that the charges are finite, symplectic and integrable, yet not conserved. We find four towers of charges forming an algebroid given by $$ \mathfrak{vir}\oplus \mathfrak{vir}\oplus $$ vir ⊕ vir ⊕ Heisenberg with three central extensions, where the base space is parametrized by the retarded time. These four charges generate diffeomorphisms of the boundary cylinder, Weyl rescalings of the boundary metric, and radial translations. We perform this study both in metric and triad variables, and use the triad to explain the covariant origin of the corner terms needed for renormalization and integrability.

Integration of gravity, magnetic, and seismic data for subsalt modeling in the Northern Red Sea

Rifts and rifted passive margins are often associated with thick evaporite layers, which challenge seismic reflection imaging in the subsalt domain. This makes understanding the basin evolution and crustal architecture difficult. An integrative, multidisciplinary workflow has been developed using the exploration well, gravity and magnetics data, together with seismic reflection and refraction data sets to build a comprehensive 3D subsurface model of the Egyptian Red Sea. Using a 2D iterative workflow first, we have constructed cross sections using the available well penetrations and seismic refraction data as preliminary constraints. The 2D forward model uses regional gravity and magnetic data to investigate the regional crustal structure. The final models are refined using enhanced gravity and magnetic data and geologic interpretations. This process reduces uncertainties in basement interpretation and magmatic body identification. Euler depth estimates are used to point out the edges of high-susceptibility bodies. We achieved further refinement by initiating a 3D gravity inversion. The resultant 3D gravity model increases precision in crustal geometries and lateral density variations within the crust and the presalt sediments. Along the Egyptian margin, where data inputs are more robust, basement lows are observed and interpreted as basins. Basement lows correspond with thin crust ([Formula: see text]), indicating that the evolution of these basins is closely related to the thinning or necking process. In fact, the Egyptian Northern Red Sea is typified by dramatic crustal thinning or necking that is occurring over very short distances of approximately 30 km, very proximal to the present-day coastline. The integrated 2D and 3D modeling reveals the presence of high-density magnetic bodies that are located along the margin. The location of the present-day Zabargad transform fault zone is very well delineated in the computed crustal thickness maps, suggesting that it is associated with thin crust and shallow mantle.