The CPT-odd and Lorentz-violating Carroll-Field-Jackiw modification of electrodynamics is discussed and we study its effects on the energy spectrum of hydrogen, as well as in the generation of a momentum-dependent electric dipole moment for charged leptons. We also briefly comment on the possibility of the detection of Lorentz violation in measurements of vacuum birefringence in resonant cavities. The bounds found are based on local laboratory experimental limits and are not competitive with the ones coming from astrophysical considerations.

We introduce modified covariant quantum algebra based on the so-called Quesne-Tkachuk algebra. By means of a deformation procedure we arrive at a class of higher-derivative models of gravity. The study of the particle spectra of these models reveals equivalence with the physical content of the well-known higher-derivative gravities. The particle spectrum exhibits the presence of spurious complex ghosts and, in light of this problem, we suggest an interesting interpretation in the context of minimal length theories. Also, a discussion regarding the nonrelativistic potential energy is proposed.

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In this work we introduce CPT-odd non-minimal Lorentz-symmetry violating couplings to the electroweak sector modifying the interaction between leptons and gauge bosons. The vertex rules allow us to calculate tree-level processes modified by the presence of the novel dimension-five operators. For definitiveness, we investigate the W decay into a lepton-neutrino pair, the Z decay into pairs of charged and neutral leptons, as well as the decay of the muon. By comparing the experimental measurements on these processes to our results we are able to place upper bounds on combinations of the background 4-vectors of up to ∼ 10 −4 GeV −1 .

Based on recent discussions on the so-called unconventional supersymmetry, we analyze a class of solutions of a 5D Chern-Simons AdS-N -SUGRA formulation without gravitino fields. With a Randall-Sundrum-type ansatz, we exploit the properties of Chern-Simons theories to find solutions to the fermionic field equations in a particular dimensional reduction context. We show that this specific dimensional reduction yields a non-trivial equation of motion for the fermionic field. We actually get a non-linear equation of motion for the fermionic fields, typical of models where torsion is present. This fermionic equation describes massive fermions with specific couplings with the bosonic supersymmetric degrees of freedom and we show that, in some specific limits, we can infer about the localization of the fermions' chirality components by means of the particular function that comes out to the dimensional reduction scheme.