Radiatively induced CPT-odd Chern-Simons term in massless QED

In this work, we study the radiative generation of the CPT-odd Lorentz-violating Chern-Simons term, arising from massless fermions. For this, we calculate the vacuum polarization tensor using the 't Hooft-Veltman regularization scheme, in which the result obtained for the coefficient of the Chern-Simons term is $(k_{AF})_\mu=-\frac{e^2}{4\pi^2}\,b_\mu$. This result leads us precisely to the same conductivity found in Weyl semimetals, i.e., the 't Hooft-Veltman regularization scheme is the correct one to be used in this context. We also discuss the temperature dependence of $(k_{AF})_\mu$, in which at high temperature, $(k_{AF})_0\to0$ and $(k_{AF})_i\to-\frac{e^2}{4\pi^2}b_i$. In the context of Weyl semimetals, these results are in accordance with the fact that the chiral magnetic current $j^\alpha=(k_{AF})_0\epsilon^{0\alpha\lambda\rho}\partial_\lambda A_\rho$ vanishes at high temperature, whereas the anomalous Hall current $j^\alpha=(k_{AF})_i\epsilon^{i\alpha\lambda\rho}\partial_\lambda A_\rho$ remains unaffected by the finite temperature.Comment: 13 pages, accepted for publication in Europhys. Let

DOMESTICS CLIMATE CHANGE POLICIES AND THE WTO

The Kyoto Protocol sets reduction targets to greenhouse gas emission levels in developed countries, including OECD and East European countries (the so-called Annex 1 Parties to the Climate Change Convention). The Kyoto Protocol gives Annex 1 countries considerable flexibility in the choice of domestic policies to meet their emissions commitments. Possible climate policies include carbon/energy taxes, subsidies, energy efficiency standards, eco-labels, and government procurement policies. In order to meet their Kyoto targets with minimum adverse effects on their economies, Annex 1 Party governments with differentiated legal and political systems are highly likely to pursue climate policies that may have the potential to bring them into conflict with their WTO obligations. This paper explores the potential interaction between these domestic climate policies and WTO rules. It argues that their potential conflicts can be avoided or at least minimized if WTO rules are carefully scrutinized, and efforts are made early on to ensure that the proposed climate policies comply with them. It suggests an early process of pursuing consultations between WTO members and the Parties to the Climate Change Convention and points to the need to further explore ways to enhance synergies between the trade and climate regimes.

Detection of spatial pattern through independence of thinned processes

Let N, N' and N'' be point processes such that N' is obtained from N by homogeneous independent thinning and N''= N- N'. We give a new elementary proof that N' and N'' are independent if and only if N is a Poisson point process. We present some applications of this result to test if a homogeneous point process is a Poisson point process.Comment: 11 pages, one figur

Land Reform and Landholdings in Brazil

land reform, land distribution, wealth distribution

Nonanalyticity of the induced Carroll-Field-Jackiw term at finite temperature

In this paper, we discuss the behavior of the Carroll-Field-Jackiw (CFJ) coefficient $k^{\mu}$ arising due to integration over massive fermions, and the modification suffered by its topological structure in the finite temperature case. Our study is based on the imaginary time formalism and summation over the Matsubara frequencies. We demonstrate that the self-energy of photon is non-analytic for the small $k^{\mu}$ limit, i.e., the static limit $(k_0=0,\vec k\rightarrow 0)$ and the long wavelength limit $(k_0\rightarrow 0,\vec k= 0)$ do not commute, while the tensorial structure of the CFJ term holds in both limits.Comment: 12 pages, 1 figur