Metallic and semi-metallic <100> silicon nanowires

Silicon nanowires grown along the -direction with a bulk Si core are studied with density functional calculations. Two surface reconstructions prevail after exploration of a large fraction of the phase space of nanowire reconstructions. Despite their energetical equivalence, one of the reconstructions is found to be strongly metallic while the other one is semi-metallic. This electronic-structure behavior is dictated by the particular surface states of each reconstruction. These results imply that doping is not required in order to obtain good conducting Si nanowires.Comment: 13 pages, 4 figures; Phys. Rev. Lett., in pres

On the perturbative generation of the higher-derivative Lorentz-breaking terms

In this paper, we describe the perturbative generation of the higher-derivative Lorentz-breaking terms for the gauge field, that is, the Myers-Pospelov term and the higher-derivative Carroll-Field-Jackiw term. These terms are explicitly calculated in the one-loop approximation and shown to be finite and ambiguous.Comment: 12 pages, version accepted to PR

A compact high-flux cold atom beam source

We report on an efficient and compact high-flux Cs atom beam source based on a retro-reflected two-dimensional magneto-optical trap (2D MOT). We realize an effective pushing field component by tilting the 2D MOT collimators towards a separate three-dimensional magneto-optical trap (3D MOT) in ultra-high vacuum. This technique significantly improved 3D MOT loading rates to greater than $8 \times 10^9$ atoms/s using only 20 mW of total laser power for the source. When operating below saturation, we achieve a maximum efficiency of $6.2 \times 10^{11}$ atoms/s/W

On aether terms in a space-time with a compact extra dimension

In this paper, for the CPT-even and CPT-odd extensions of the QED, we explicitly obtain the aether-like corrections for the electromagnetic field in the case when the space-time involves an extra compact spatial dimension besides of usual four dimensions. Our methodology is based on an explicit summation over the Kaluza-Klein tower of fields which is no more difficult than the finite-temperature calculations. The quantum corrections turn out to be large as the extra dimension is small. We demonstrate that in the CPT-even case, the extra dimension manifests itself through a new scalar particle.Comment: 9 page

On the Adler-Bell-Jackiw anomaly in a Horava-Lifshitz-like QED

We show the absence of the ABJ anomaly for the Horava-Lifshitz-like QED with any even $z$. Besides of this, we study the graph contributing to the ABJ anomaly at non-zero temperature and extend the Fujikawa's methodology of studying the integral measure for our model.Comment: 9 pages, version accepted to EP