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Register a new userEffect of electromagnetic fields on deformed AdS_5 models
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The response of a QCD-like gauge theory, holographically dual to a deformed $mathrm{AdS}_5$ model, to constant electromagnetic fields is thoroughly investigated. The calculations in this paper are performed for three different cases, i.e., with only a quadratic correction, with only a logarithmic correction, and with both quadratic and logarithmic corrections, for which the parameters are chosen as the ones found in cite{quadlog} by fitting to experimental and lattice results. The critical electric fields of the system are found by analyzing its total potential. Comparing the total potential for the three cases, we observe that the quarks can be liberated easier in quadratic and then logarithmic case, for a given electric field. Then, by calculating the expectation value of a circular Wilson loop, the pair production rate is evaluated while a constant electric field as well as a constant magnetic field are present. The aforementioned result obtained from the potential analysis is also confirmed here when no magnetic fields are present. We moreover find that the presence of a magnetic field perpendicular to the direction of the electric field suppresses the rate of producing the quark pairs and accordingly increases the critical electric field below which the Schwinger effect does not occur. Interestingly, the presence of a parallel magnetic field alone does not change the response of the system to the external electric field, although it enhances the creation rate when a perpendicular magnetic field is also present.
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In this paper, considering the correspondence between spin chains and string sigma models, we explore the rotating string solutions over $ eta $ deformed $ AdS_5 times S^{5} $ in the so called fast spinning limit. In our analysis, we focus only on the bosonic part of the full superstring action and compute the relevant limits on both $(R times S^{3})_{eta} $ and $(R times S^{5})_{eta} $ models. The resulting system reveals that in the fast spinning limit, the sigma model on $ eta $ deformed $S^5$ could be $textit{approximately}$ thought of as the continuum limit of anisotropic $ SU(3) $ Heisenberg spin chain model. We compute the energy for a certain class of spinning strings in deformed $S^5$ and we show that this energy can be mapped to that of a similar spinning string in the purely imaginary $beta$ deformed background.
Positive energy unitary irreducible representations of $SU(2,2)$ can be constructed with the aid of bosonic oscillators in (anti)fundamental representation of $SU(2)_Ltimes SU(2)_R$ that are closely related to Penrose twistors. Starting with the correspondence between the doubleton representations, homogeneous functions on projective twistor space and on-shell $SL(2,mathbb C)$ generalized Weyl curvature spinors and their low-spin counterparts, we study in the similar way the correspondence between the massless representations, homogeneous functions on ambitwistor space and, via the Penrose transform, with the gauge fields on Minkowski boundary of $AdS_5$. The possibilities of reconstructing massless fields on $AdS_5$ and some applications are also discussed.
We construct actions of higher spin fields interacting with gravity on AdS_5 backgrounds such that the Compton scattering amplitudes of the interaction are tree-level unitary. We then consider higher-spin fields in the Randall-Sundrum scenario. There, in the fermionic case, we construct a tree-level unitary action of higher spin fields interacting with branes and linearised gravity. In the bosonic case we show that this is not in general possible. A tree-level unitary action of bosonic higher spins interacting with linearised gravity and branes is only possible in the following cases: The brane is a pure tension brane and/or Dirichlet boundary conditions are imposed thereby making bosonic higher spin fields invisible to a brane observer. We finally show that higher spins in Randall-Sundrum II braneworlds can only be produced by (decay into) gravitons at trans-Planckian scales. We end by commenting on the possible relevance of higher-spin unparticles as Dark Matter candidates.
We describe the deformed E.T. quantization rules for kappa-deformed free quantum fields, and relate these rules with the kappa-deformed algebra of field oscillators.
In order to obtain free kappa-deformed quantum fields (with c-number commutators) we proposed new concept of kappa-deformed oscillator algebra [1] and the modification of kappa-star product [2], implementing in the product of two quantum fields the change of standard kappa-deformed mass-shell conditions. We recall here that the kappa-deformed oscillators recently introduced in [3]-[5] lie on standard kappa-deformed mass-shell. Firstly, we study kappa-deformed fields with the standard kappa-star product, what implies that in the oscillator algebra the corresponding kappa-deformed oscillators lie on standard kappa-deformed mass-shell. We argue that for the kappa-deformed algebra of such field oscillators which carry fourmomenta on kappa-deformed mass-shell it is not possible to obtain the free quantum kappa-deformed fields with the c-number commutators. Further, we study kappa-deformed quantum fields with the modified kappa-star product which implies the modification of kappa-deformed mass-shell. We obtain large class of kappa-deformed statistics depending on six arbitrary functions which provides the c-number field commutator functions. Such general class of kappa-oscillators can be described as the kappa-deformation of standard oscillator algebra obtained by composing general kappa-deformed multiplication with the deformation of the flip operator.
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