23 citations · 129 across the 18 of their papers we have counts for
18 papers
Torsionful Killing-Yano Forms under T-Duality: Transformation Conditions and Emergent Isometries
Özgür Kelekçi, Ümit Ertem, Özgür Açık
We investigate the transformation of Killing-Yano (KY) -forms under Abelian T-duality in the presence of a non-trivial three-form torsion. Using a torsionful, metric-compatible…
Symmetries of modified Dirac operators in supergravity flux backgrounds
Ümit Ertem
Modifications of Dirac operators in supergravity flux backgrounds are considered. Modified spin curvature operators and squares of modified Dirac operators corresponding to Schrödi…
Generalized symmetry superalgebras
Özgür Açık, Ümit Ertem
We generalize the symmetry superalgebras of isometries and geometric Killing spinors on a manifold to include all the hidden symmetries of the manifold generated by Killing spinors…
Spin raising and lowering operators for Rarita-Schwinger fields
Özgür Açık, Ümit Ertem
Spin raising and lowering operators for massless field equations constructed from twistor spinors are considered. Solutions of the spin- massless Rarita-Schwinger equa…
Harmonic spinors from twistors and potential forms
Ümit Ertem
Symmetry operators of twistor spinors and harmonic spinors can be constructed from conformal Killing-Yano forms. Transformation operators relating twistors to harmonic spinors are…
Rigidity of Killing-Yano and conformal Killing-Yano superalgebras
Ümit Ertem
Symmetry algebras of Killing vector fields and conformal Killing vectors fields can be extended to Killing-Yano and conformal Killing-Yano superalgebras in constant curvature manif…
Gauged twistor spinors and symmetry operators
Ümit Ertem
We consider gauged twistor spinors which are supersymmetry generators of supersymmetric and superconformal field theories in curved backgrounds. We show that the spinor bilinears o…
Quasinormal modes of BTZ black hole and Hawking-like radiation in graphene
B. S. Kandemir, Ümit Ertem
The Bañados-Teitelboim-Zanelli (BTZ) black hole model corresponds to a solution of (2+1)-dimensional Einstein gravity with negative cosmological constant, and by a conformal rescal…
Twistor spinors and extended conformal superalgebras
Ümit Ertem
We show that the first-order symmetry operators of twistor spinors can be constructed from conformal Killing-Yano forms in conformally-flat backgrounds. We express the conditions o…
Supergravity backgrounds and symmetry superalgebras
Ümit Ertem
We consider the bosonic sectors of supergravity theories in ten and eleven dimensions which correspond to the low energy limits of string theories and M-theory. The solutions of su…
Symmetry operators of Killing spinors and superalgebras in AdS_5
Ümit Ertem
We construct the first-order symmetry operators of Killing spinor equation in terms of odd Killing-Yano forms. By modifying the Schouten-Nijenhuis bracket of Killing-Yano forms, we…
Hidden symmetries and Lie algebra structures from geometric and supergravity Killing spinors
Özgür Açık, Ümit Ertem
We consider geometric and supergravity Killing spinors and the spinor bilinears constructed out of them. The spinor bilinears of geometric Killing spinors correspond to the antisym…
Higher-degree Dirac Currents of Twistor and Killing Spinors in Supergravity Theories
Özgür Açık, Ümit Ertem
We show that higher degree Dirac currents of twistor and Killing spinors correspond to the hidden symmetries of the background spacetime which are generalizations of conformal Kill…
Transgression field theory at the interface of topological insulators
Özgür Açık, Ümit Ertem
Topological phases of matter can be classified by using Clifford algebras through Bott periodicity. We consider effective topological field theories of quantum Hall systems and top…
Couplings of gravitational currents with Chern-Simons gravities
Ümit Ertem, Özgür Açık
The coupling of conserved p-brane currents with non-Abelian gaugetheories is done consistently by using Chern-Simons forms. Conserved currents localized on p-branes that have a gra…
Generalized Chern-Simons Modified Gravity in First-Order Formalism
Ümit Ertem, Özgür Açık
We propose a generalization of Chern-Simons (CS) modified gravity in first-order formalism. CS modified gravity action has a term that comes from the chiral anomaly which is Pontry…
Basic Gravitational Currents and Killing-Yano Forms
Ö. Açık, Ü. Ertem, M. Önder +1
It has been shown that for each Killing-Yano (KY)-form accepted by an -dimensional (pseudo)Riemannian manifold of arbitrary signature, two basic gravitational currents can be de…
First-order symmetries of Dirac equation in curved background: a unified dynamical symmetry condition
Ö. Açık, Ü. Ertem, M. Önder +1
It has been shown that, for all dimensions and signatures, the most general first-order linear symmetry operators for the Dirac equation including interaction with Maxwell field in…