arXiv subjects

Nihat Sadik Deger

Publications and source records attributed to Nihat Sadik Deger.

At least 19 recordsLinked to original sources

arXiv2026

Minimal Massive Gravity Coupled to Higher Spins

Among three-dimensional massive gravities, Minimal Massive Gravity (MMG) is distinguished by a parameter regime in which the AdS bulk theory and the dual conformal field theory can be simultaneously unitary. We couple MMG to a finite tower of higher-spins by promoting the fields of its first-order formulation to $\mathfrak{sl}(N)$-valued ones. We also present an extended formulation involving a group-valued Stückelberg scalar, which realizes the higher-spin translations broken by the massive deformation. We then construct AdS$_2\times$S$^1$ solutions carrying higher-spin hair specific to the massive theory. Finally, we analyse the mass spectrum of the higher-spin modes around AdS$_3$.

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arXiv2025

Supersymmetric Null and Timelike Warped AdS and Strings in D=3, N=2 Gauged Supergravity

We classify and construct supersymmetric solutions of D=3, N=2 gauged supergravity extended with a Fayet-Iliopoulos term, and null and timelike warped AdS spacetimes are among them. From the first one, it is possible to obtain a well-defined black hole by periodic identification. We also find charged string solutions that interpolate between two supersymmetric AdS or Minkowski extrema of the scalar potential, one of which corresponds to a horizon with a singularity behind it, and the other determines the asymptotic geometry.

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arXiv2025

Timelike Supersymmetric Solutions of D=3, N=4 Supergravity

We study timelike supersymmetric solutions of a $D=3, N=4$ gauged supergravity using Killing spinor bilinears method and prove that AdS$_3$ is the only solution within this class. We then consider the ungauged version of this model. It is found that for this type of solutions, the ungauged theory effectively truncates to a supergravity coupled to a sigma model with a 2-dimensional hyperbolic target space $\mathbb{H}^2$, and all solutions can be expressed in terms of two arbitrary holomorphic functions. The spacetime metric is a warped product of the time direction with a 2-dimensional space, and the warp factor is given in terms of the Kähler potential of $\mathbb{H}^2$. We show that when the holomorphic function that determines the sigma model scalar fields is not constant, the metric on the sigma model target manifold becomes part of the spacetime metric. We then look at some special choices for these holomorphic functions for which the spacetime metric and the Killing spinors are only radial dependent. We also derive supersymmetric null solutions of the ungauged model which are pp-waves on the Minkowski spacetime.

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arXiv2024

Rotating AdS$_3 \times$S$^3$ and Dyonic Strings from 3-Dimensions

We make a general Killing spinor analysis of a particular $D=3, \, N=4$ gauged supergravity that comes from a consistent S$^3$ reduction of $D=6, \, N=(1,0)$ supergravity coupled to a single chiral tensor multiplet. We then focus on its supersymmetric solutions with a null Killing vector and find three new ones. Two of these, namely the null warped AdS$_3$ (also known as the Schrödinger spacetime) and the charged domain wall solutions, admit non-trivial gauge fields which give rise to rotating solutions in 6-dimensions. The uplift of the first one produces an interesting AdS$_3 \times$S$^3$ background with a non-trivial rotation in the $U(1)$ fiber direction of the S$^3$ which retains the Schrödinger scale invariance that the seed solution has. The second one leads to the well-known rotating dyonic string solution. Finally, the uplift of the third one, which is a domain wall solution with no gauge fields, results in a distribution of dyonic strings.

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arXiv2024

The General Supersymmetric Solution of Minimal Massive Supergravity

Minimal massive supergravity is the supersymmetric extension of minimal massive gravity in three dimensions. The theory admits a supersymmetric anti-de Sitter vacuum around which the propagating modes of spin 2 and 3/2 combine into a supermultiplet. In this letter, we determine the most general supersymmetric solution of the theory by analyzing its Killing spinor equations. Just as for topologically massive supergravity, the general supersymmetric solution is a plane wave with a null Killing vector field. As a particular subclass we find null-warped AdS3 spaces and, with proper periodic identifications, null-warped AdS3 black holes.

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arXiv2024

Waves and strings in an interacting conformal chiral 2-form theory in six dimensions

In six dimensions there exists a unique one-parameter family of non-linear conformal electrodynamics for a chiral 2-form gauge field which includes (in a free-field limit) the linear chiral 2-form theory and is related, by dimensional reduction, to the four-dimensional ModMax electrodynamics. In this work, we present the first exact solutions of this theory in presence of gravity. In particular, we will consider plane-wave, Robinson-Trautman, and self-dual dyonic string configurations, generalizing well-known solutions of this type in six-dimensional supergravities with linear chiral 2-form multiplets.

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arXiv2024

Holographic RG flows and boundary conditions in a 3D gauged supergravity

In this work we focus on the study of RG flows of conformal field theories that are holographically dual to Poincaré domain wall solutions in $D=3$, $\mathcal{N}=(2,0)$ gauged supergravity coupled to a sigma model with target space $SU(1, 1)/U(1) = H^2$. This theory is truncated to a subsector where the vector field and phase of the scalar field vanish and we consider different boundary conditions for the remaining real scalar field. The RG flows, which are mostly non-superysymmetric, are analyzed by treating the supergravity field equations as a dynamical system for the scalar field and its derivative with respect to the scale factor. Phase diagrams are constructed for different values of the parameter $a^2$, which is related to the curvature of the scalar manifold. The behavior of solutions near the boundary is used to determine their type based on the expansion of the corresponding fake superpotential. By incorporating information on the boundary conditions, the obtained RG flows are interpreted using the holographic dictionary. Numerical solutions and plots of the fake superpotential are also provided.

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arXiv2023

Minimal massive supergravity and new theories of massive gravity

We present an action for minimal massive gravity (MMG) in three dimensions in terms of a dreibein and an independent spin connection. Furthermore, the construction provides an action principle for an infinite family of so-called third-way consistent generalizations of the three-dimensional Einstein field equations, including exotic massive gravity and new higher-order generalizations. It allows to systematically construct the matter couplings for these models, including the couplings to fermions, depending on the spin connection. In particular, we construct different supersymmetric extensions of MMG, and derive their second order fermionic field equations. This establishes a new class of three-dimensional supergravity theories and we discuss their limit to topological massive supergravity. Finally, we identify the landscape of (A)dS vacua of the supersymmetric models. We analyze the spectrum and the unitarity properties of these vacua. We recover the known AdS vacua of MMG which are bulk and boundary unitary.

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arXiv2023

Minimal Massive Supergravity

Minimal massive gravity in three dimensions propagates a single massive spin-2 mode around an AdS vacuum. It is distinguished by allowing for vacua with positive central charges of the asymptotic conformal algebra and a bulk graviton of positive energy. We present a new action for the model (and its higher order extensions) in terms of a dreibein and an independent spin connection. From this, we construct its supersymmetric extension. Surprisingly, all vacua complying with bulk and boundary unitarity appear to break supersymmetry spontaneously. In contrast, all supersymmetric vacua have a negative central charge whenever the bulk graviton has positive energy.

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arXiv2022

Generalized 11D supergravity equations from tri-vector deformations

In arXiv:2203.03372 we presented a modification of 11-dimensional supergravity field equations which upon dimensional reduction yields generalized supergravity equations in 10-dimensions. In this paper we provide full technical details of that result which is based on SL(5) exceptional field theory. The equations are obtained by making a non-unimodular tri-vector Yang-Baxter deformation which breaks the initial GL(11) symmetry down to GL(7)xGL(4). We also give some non-trivial solutions to these equations.

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arXiv2022

A note on the third way consistent deformation of Yang-Mills theory

Three-dimensional Yang-Mills theory allows for a deformation quadratic in the field strengths which can not be integrated to a local action without auxiliary fields. Yet, its covariant divergence consistently vanishes after iterating the equation, realizing a spin-1 analogue of `minimal massive gravity', which has been dubbed `third way consistent'. In this note, we show that after dualization of the three-dimensional gauge fields, the model possesses a natural action as a Chern-Simons coupled gauged sigma model. In this dual formulation, coupling to matter and to gravity becomes straightforward. As a direct application, we derive the coupling of the model to N=1 supergravity.

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arXiv2022

The Third Way to Interacting $p$-form Theories

We construct a class of interacting $(d-2)$-form theories in $d$ dimensions that are `third way' consistent. This refers to the fact that the interaction terms in the $p$-form field equations of motion neither come from the variation of an action nor are they off-shell conserved on their own. Nevertheless the full equation is still on-shell consistent. Various generalizations, e.g. coupling them to $(d-3)$-forms, where 3-algebras play a prominent role, are also discussed. The method to construct these models also easily recovers the modified 3$d$ Yang-Mills theory obtained earlier and straightforwardly allows for higher derivative extensions.

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arXiv2022

Generalizing eleven-dimensional supergravity

We develop a procedure to reproduce the ten-dimensional generalized supergravity equations from T-duality covariant equations, that facilitates generalization to U-duality covariant formulations of eleven-dimensional supergravity. The latter leads to a modification of the eleven-dimensional supergravity equations with terms that contain a rank-2 tensor field $J^{mn}$ which is the eleven-dimensional analog of the non-unimodularity Killing vector $I^m$ in ten dimensions.

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arXiv2022

A Review of Third Way Consistent Theories

We will give an overview of the "third way consistent" theories. Field equations of such models do not come from the variation of a local action without auxiliary fields, yet their covariant divergences still vanish on-shell. First examples were discovered in three dimensions which were pure massive gravity and Yang-Mills theories. However, recently interacting $p$-form theories with this property in arbitrary dimensions were also constructed. After explaining construction of these theories and some of their general features, we will discuss some open problems and future directions

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arXiv2021

The Third way to 3D Supersymmetric Massive Yang-Mills Theory

We construct three-dimensional, $\mathcal{N}=1$ off-shell supersymmetric massive Yang-Mills (YM) theory, whose YM equation is "third way" consistent. This means that the field equations of this model do not come from variation of a local action without additional fields, yet the gauge covariant divergence of the YM equation still vanishes on-shell. To achieve this, we modify the massive Majorana spinor equation so that its supersymmetry variation gives the modified YM equation, whose bosonic part coincides with the third way consistent pure massive YM model.

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arXiv2020

Supersymmetric Dyonic Strings in 6-Dimensions from 3-Dimensions

It was shown in arXiv:1410.7168 that compactifying $D=6$, $\mathcal{N}=(1,0)$ ungauged supergravity coupled to a single tensor multiplet on S$^3$ one gets a particular $D=3$, $\mathcal{N}=4$ gauged supergravity which is a consistent reduction. We construct two supersymmetric black string solutions in this 3-dimensional model with one and two active scalars respectively. Uplifting the first, one gets a dyonic string solution in $D=6$ that has been known for a long time. Whereas, uplifting the second solution, one finds a very interesting configuration where magnetic strings are located uniformly on a circle in a plane within the 4-dimensional flat transverse space and electric strings are distributed homogeneously inside this circle. Both solutions have $\mathrm{AdS}_3 \times$ S$^3$ limits.

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arXiv2020

Spontaneously Broken 3d Hietarinta/Maxwell Chern-Simons Theory and Minimal Massive Gravity

We show that minimal massive 3d gravity (MMG), as well as the topological massive gravity, are particular cases of a more general `minimal massive gravity' theory (with a single massive propagating mode) arising upon spontaneous breaking of a local symmetry in a Chern-Simons gravity based on a Hietarinta or Maxwell algebra. Similar to the MMG case, the requirements that the propagating massive mode is neither tachyon nor ghost and that the central charges of an asymptotic algebra associated with a boundary CFT are positive, impose restrictions on the range of the parameters of the theory.

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arXiv2019

Exotic massive 3D gravities from truncation

We introduce a systematic way of constructing 3D exotic massive gravity theories in the first order formulation. Our method is based on truncating a single degree of freedom in the parity odd gravity models found earlier in arXiv:1405.6213 and supplementing it with appropriate potential terms such that the resulting models have well-defined metric equations but their Bianchi identities are satisfied only on-shell. Hence, they are `third way' consistent. We first re-derive two already known exotic theories using our approach and then construct an extended exotic massive gravity model whose metric field equation is sixth order in derivatives. We also explain how to check Bianchi identities using the first order formulation.

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