International Journal of Modern Physics A

We give a review on our recent work arXiv:1006.0779 [hep-th] and arXiv:1006.1719 [hep-th], in which properties of holographic strange metals were investigated. The background is chosen to be anisotropic scaling solution in Einstein–Maxwell–Dilaton theory with a Liouville potential. The effects of bulk Maxwell field, an extra U(1) gauge field and probe D-branes on the DC conductivity, the DC Hall conductivity and the AC conductivity are extensively analyzed. We classify behaviors of the conductivities according to the parameter ranges in the bulk theory and characterize conditions when the holographic results can reproduce experimental data.

We consider a loop mixing of two fermion fields of opposite parities whereas the parity is conserved in Lagrangian. Such kind of mixing is specific for fermions and has no analogy in boson case. Possible applications of this effect may be related with physics of baryon resonances. The obtained matrix propagator defines a pair of unitary partial amplitudes which describe the production of resonances of spin J and different parity 1/2^± or 3/2^±. The use of our amplitudes for joint description of πN partial waves P₁₃ and D₁₃ shows that the discussed effect is clearly seen in these partial waves as the specific form of interference between resonance and background. Another interesting application of this effect may be related with partial waves S₁₁ and P₁₁, where the picture is more complicated due to presence of several resonance states.

A procedure for implementation of the generating equations in the linear sigma model of low energy QCD is presented. For any explicit symmetry breaking term, this procedure computes the masses of scalar and pseudoscalar mesons as well as various three-point and four-point interaction vertices that are needed in calculation of different decay widths and scattering amplitudes.

We construct supersymmetric Pati–Salam flux vacua in AdS from intersecting D6-branes on T⁶/(ℤ₂ × ℤ′₂). The models constructed have three generations of MSSM matter plus right-handed neutrinos. Because the cycles wrapped by the D-branes are rigid there are no extra massless fields in the adjoint representation, arising as open-string moduli. However, we find that it is problematic to break the Pati–Salam gauge symmetry to the Standard Model (SM) while keeping the SM hypercharge massless.

We construct D-brane embeddings in by studying the consistency conditions following from the pull back of target space equations of motion. We explicitly discuss the supersymmetry preserved by these embeddings by analyzing the compatibility of kappa symmetry projections with the target space Killing spinors in each case. The embeddings correspond to AdS/dCFT dualities involving ABJM theories with a defect. We also comment on the defect CFT.

We extend a previous computation of the TJJ correlator, involving the energy–momentum tensor of an Abelian gauge theory and two vector currents (J ≡ J_V), to the case of mixed axial-vector/vector currents (J_A). The study is performed in analogy to the case of the AVV vertex for the chiral anomaly. We derive the general structure of the anomalous Ward identities and provide explicit tests of their consistency using Dimensional Reduction. Mixed massive correlators of the form TJ_V J_A are shown to vanish both by Ward identities and by C-invariance. The result is characterized by the appearance of massless scalar degrees of freedom in the coupling of chiral and vector theories to gravity, affecting both the soft and the ultraviolet region of the vertex. This is in agreement with previous studies of the effective action of gauge and conformal anomalies in QED and QCD.

We study the connection, at the quantum level, between (d = 2+1)-dimensional self-dual models with actions of growing (from first to fourth) order, governing the dynamics of helicity ±2 massive excitations. We obtain identities between generating functionals of the different models using the path-integral framework, this allowing us to establish dual maps among relevant vacuum expectation values. We check consistency of these vacuum expectation values with the gauge invariance gained in each mapping.