Lorentz-violating nonminimal coupling contributions in mesonic hydrogen atoms and generation of photon higher-order derivative terms

We have studied the contributions of Lorentz-violating CPT-odd and CPT-even nonminimal couplings to the energy spectrum of the mesonic hydrogen and the higher-order radiative corrections to the effective action of the photon sector of a Lorentz-violating version of the scalar electrodynamics. By considering the complex scalar field describes charged mesons (pion or kaon), the non-relativistic limit of the model allows to attain upper-bounds by analyzing its contribution to the mesonic hydrogen energy. By using the experimental data for the $1S$ strong correction shift and the pure QED transitions $4P \rightarrow 3P$, the best upper-bound for the CPT-odd coupling is $<10^{-12}\text{eV}^{-1}$ and for the CPT-even one is $<10^{-16}\text{eV}^{-2}$. Besides, the CPT-odd radiative correction to the photon action is a dimension-5 operator which looks like a higher-order Carroll-Field-Jackiw term. The CPT-even radiative contribution to the photon effective action is a dimension-6 operator which would be a higher-order derivative version of the minimal CPT-even term of the standard model extension

Mapping archaeological landscapes through aerial thermographic imaging

This project aims to develop techniques for efficient, high-resolution aerial thermal infrared imaging of archaeological sites and surrounding landscapes. Archaeologists have been aware since the 1970s that images which record thermal wavelengths of light can reveal surface and buried archaeological features that are otherwise invisible, but the costs and difficulty of the technology has made its application beyond the reach of most scholars. This project will develop methods for collecting high-resolution thermal infrared images using a specialized camera mounted on a remote-controlled unmanned aerial vehicle. Conducting surveys at archaeological sites in three environmentally and culturally distinct regions--Cyprus, Dubai and South Dakota--our results will demonstrate the potential and limitations of the technology in a variety of archaeological contexts, offer guidelines for executing surveys and processing results, and serve as a blueprint for other investigators in the future

Conformal invariance of massless Duffin-Kemmer-Petiau theory in Riemannian space-times

We investigate the conformal invariance of massless Duffin-Kemmer-Petiau theory coupled to riemannian space-times. We show that, as usual, in the minimal coupling procedure only the spin 1 sector of the theory -which corresponds to the electromagnetic field- is conformally invariant. We show also that the conformal invariance of the spin 0 sector can be naturally achieved by introducing a compensating term in the lagrangian. Such a procedure -besides not modifying the spin 1 sector- leads to the well-known conformal coupling between the scalar curvature and the massless Klein-Gordon-Fock field. Going beyond the riemannian spacetimes, we briefly discuss the effects of a nonvanishing torsion in the scalar case.Comment: 8 pages, no figures. Major changes in contend and results. To appear in Class.Quant.Gra

Lorentz-violating effects in the Bose-Einstein condensation of an ideal bosonic gas

We have studied the effects of Lorentz-violation in the Bose-Einstein condensation (BEC) of an ideal boson gas, by assessing both the nonrelativistic and ultrarelativistic limits. Our model describes a massive complex scalar field coupled to a CPT-even and Lorentz-violating background. We irst analyze the nonrelativistic case, at this level by using experimental data, we obtain upper-bounds for some LIV parameters. In the sequel, we have constructed the partition function for the relativistic ideal boson gas which to be able of a consistent description requires the imposition of severe restrictions on some LIV coefficients. In both cases, we have demonstrated that the LIV contributions are contained in an overall factor, which multiplies almost all thermodynamical properties. An exception is the fraction of the condensed particles.Comment: 7 pages Latex2e. To be published in Modern Physics Letters

On the aether-like Lorentz-breaking actions

We demonstrate the generation of the CPT-even, aether-like Lorentz-breaking actions for the scalar and electromagnetic fields via their appropriate Lorentz-breaking coupling to spinor fields in three, four and five space-time dimensions. Besides, we show that the aether-like terms for the spinor field also can be generated as a consequence of the same couplings. Also we discuss the dispersion relations in the theories with aether-like Lorentz-breaking terms and find the tree-level effective (Breit) potential for fermion scattering and the one-loop effective potential corresponding to the action of the scalar field.Comment: 18 pages, version accepted to Physical Review

Lorentz-violating contributions of the Carroll-Field-Jackiw model to the CMB anisotropy

We study the finite temperature properties of the Maxwell-Carroll-Field-Jackiw (MCFJ) electrodynamics for a purely spacelike background. Starting from the associated finite temperature partition function, a modified black body spectral distribution is obtained. We thus show that, if the CMB radiation is described by this model, the spectrum presents an anisotropic angular energy density distribution. We show, at leading order, that the Lorentz-breaking contributions for the Planck's radiation law and for the Stefan-Boltzmann's law are nonlinear in frequency and quadratic in temperature, respectively. Using our results, we set up bounds for the Lorentz-breaking parameter, and show that Lorentz violation in the context of the MCFJ model is unable to yield the known CMB anisotropy (of 1 part in $10^{5})$

Revealing invisible brews: a new approach to the chemical identification of ancient beer

While ancient Near Eastern cuneiform texts and iconography unambiguously demonstrate the social, economic, and ritual significance of beer, direct archaeological evidence for beer production or consumption remains surprisingly rare. This scarcity of material evidence renders it difficult to extrapolate information about the ingredients and production processes of beer, on the one hand, and the paraphernalia and social contexts of its consumption, on the other. In recent decades, organic residue analysis has become an essential tool in the identification of ancient alcoholic beverages, but research on Near Eastern beer has focused largely on production and storage vessels, whose form, archaeological context, and associated macroscopic residues already indicated their use in beer production. In this paper, we present a novel field sampling protocol that prevents contamination along with a refined organic residue analysis methodology that relies on a series of co-occurring compounds to identify confidently beer in ceramic vessels. The same compounds were identified in several modern beer samples and, thus, support our identification of a similar fermented barley-based beverage in archaeological samples from the late second millennium BCE site of Khani Masi in northeastern Iraq. The results presented in this paper allow us, for the first time, to unambiguously link a diverse range of vessel types to the consumption and production of beer, identify a fundamental change in Mesopotamian consumption practices, and shed light on the cultural dimensions of Babylonia's encounter with the Zagros-Mesopotamian borderlands