Let f: A → B be a ring homomorphism of not necessarily unital rings and I A an ideal which is mapped by f isomorphically to an ideal of B. The obstruction to excision in K-theory is the failure of the map between relative ...

We perform a very detailed investigation into the possibility of Lorentz and CPT violations in the photon sector, of the Chern-Simons form, being induced by radiative corrections arising from the Lorentz and CPT noninvariant ...

The gauge invariance of Quantum Electrodynamics establishes a non massive character for the photon field. Nevertheless, corrections at one loop level for the self-energy of the photon can induce mass generation in some ...

Let B be the ring of bounded operators in a complex, separable Hilbert space. For p > 0 consider the Schatten ideal Lp consisting of those operators whose sequence of singular values is p-summable; put S = S p Lp. Let G ...

Electromagnetic driving in a honeycomb lattice can induce gaps and topological edge states with a structure of increasing complexity as the frequency of the driving lowers. While the high frequency case is the most simple ...

There has been renewed interest in the path-integral computation of the partition function of AdS3 gravity, both in the metric and Chern-Simons formulations. The one-loop partition function around Euclidean AdS3 turns out ...

Symmetries play a key role in investigation of the laws of Nature. Sometimes, unusual properties of a physical system indicate on the presence of a hidden symmetry. The analysis of the latter helps to understand better the ...