In this paper we consider both Abelian as well as non-Abelian T-duals of the Klebanov-Witten background and inspect their various Penrose limits. We show that these backgrounds admit pp-wave solutions in the neighbourhood of appropriate null geodesics. We study the quantization of closed string propagating on some of the resulting pp-wave backgrounds. We consider the field theory duals for these geometries and compute the respective holographic central charges.

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We present a formulation of heterotic Double Field Theory (DFT), where the fundamental fields are in O(D, D) representations. The theory is obtained splitting an O(D, D + K ) duality invariant DFT. This procedure produces a Green-Schwarz mechanism for the generalized metric, and a fundamental gauge field which transforms as a gauge connection only to leading order. After parametrization, the former induces a non-covariant transformation on the metric tensor, which can be removed considering field redefinitions, and an ordinary Green-Schwarz mechanism on the b-field. Within this framework we explore perturbative properties of heterotic DFT. We use a relaxed version of the generalized Kerr-Schild ansatz (GKSA), where the generalized background metric is perturbed up to quadratic order considering a single null vector and the gauge field is linearly perturbed before parametrization. Finally we compare the dynamics of the gauge field and the generalized metric in order to inspect the behavior of the classical double copy correspondence at the DFT level.

We compute spin 2 spectrum associated with massive graviton fluctuations in γ-deformed Gaiotto-Maldacena background those are holographically dual to marginal deformations of N = 2 SCFTs in four dimensions. Under the special circumstances, we analytically estimate the spectra both for the γ-deformed Abelian T dual (ATD) as well as the non-Abelian T dual (NATD) cases where we retain ourselves upto leading order in the deformation parameter. Our analysis reveals a continuous spectra which is associated with the breaking of the U (1) isometry (along the directions of the internal manifold) in the presence of the γ-deformation. We also comment on the effects of adding flavour branes into the picture and the nature of the associated spin 2 operators in the dual N = 1 SCFTs.

We compute spin 2 spectrum associated with massive graviton fluctuations in γ-deformed Gaiotto-Maldacena background those are holographically dual to marginal deformations of $$ \mathcal{N} $$ N = 2 SCFTs in four dimensions. Under the special circumstances, we analytically estimate the spectra both for the γ-deformed Abelian T dual (ATD) as well as the non-Abelian T dual (NATD) cases where we retain ourselves upto leading order in the deformation parameter. Our analysis reveals a continuous spectra which is associated with the breaking of the U(1) isometry (along the directions of the internal manifold) in the presence of the γ-deformation. We also comment on the effects of adding flavour branes into the picture and the nature of the associated spin 2 operators in the dual $$ \mathcal{N} $$ N = 1 SCFTs.