A novel strong coupling expansion of the QCD Hamiltonian

Introducing an infinite spatial lattice with box length a, a systematic expansion of the physical QCD Hamiltonian in \lambda = g^{-2/3} can be obtained. The free part is the sum of the Hamiltonians of the quantum mechanics of spatially constant fields for each box, and the interaction terms proportional to \lambda^n contain n discretised spatial derivatives connecting different boxes. As an example, the energy of the vacuum and the lowest scalar glueball is calculated up to order \lambda^2 for the case of SU(2) Yang-Mills theory.Comment: Talk given at the 6th International Workshop on "Critical Point and Onset of Deconfinement (CPOD)", Dubna, Russia, 23-29 August 201

Tritium spelta L. – Suebian crop? An ethnographic hypothesis on genetic trial

Until the 20th century, spelt (Triticum spelta) was the traditional wheat used in the North-West of the Iberian Peninsula. A recently proposed ethnographic thesis states that this cereal was a vestige and heritage of the Germanic Suebi kingdom that established in Gallecia between 410 and 584. The present study aims to verify the mentioned thesis and to draw conclusions about possible migrations routes of the suebians. The genetic comparison included Triticum spelta L. samples of North-West-Iberian origin and a large number of samples from other Eurasian regions, including alleged suebian homeland regions (e.g. Suabia/Germany) before they immigrated in the Peninsula. An approximately 1-kb sequence, including a part of the promoter and the coding region of the high molecular-weight (HMW) glutenin B1-1 subunit gene of 48 accessions were analysed by allelic differentiation. The mutual similarities between all sequences were determined by multiple alignment and using the Neighbor Joining clustering method (Bionumerics software). Our data show that Iberian, Mediterranean and Eurasian varieties clearly shared genetic similarities, whereas the varieties from Central and North Europe grouped in other clusters. We therefore suggest that this cereal was not a vestige of the Germanic Suebi kingdom that established in Gallecia.Fundação para a Ciência e a Tecnologia (FCT) - POCI 2010; POCI/HEC/56971/2004.FEDER

Strong magnetic coupling of an ultracold gas to a superconducting waveguide cavity

Placing an ensemble of $10^6$ ultracold atoms in the near field of a superconducting coplanar waveguide resonator (CPWR) with $Q \sim 10^6$ one can achieve strong coupling between a single microwave photon in the CPWR and a collective hyperfine qubit state in the ensemble with $g_\textit{eff} / {2 \pi} \sim 40$ kHz larger than the cavity line width of ${\kappa}/{2 \pi} \sim 7$ kHz. Integrated on an atomchip such a system constitutes a hybrid quantum device, which also can be used to interconnect solid-state and atomic qubits, to study and control atomic motion via the microwave field, observe microwave super-radiance, build an integrated micro maser or even cool the resonator field via the atoms

Observation of shock waves in a large Bose-Einstein condensate

We observe the formation of shock waves in a Bose-Einstein condensate containing a large number of sodium atoms. The shock wave is initiated with a repulsive, blue-detuned light barrier, intersecting the BEC, after which two shock fronts appear. We observe breaking of these waves when the size of these waves approaches the healing length of the condensate. At this time, the wave front splits into two parts and clear fringes appear. The experiment is modeled using an effective 1D Gross-Pitaevskii-like equation and gives excellent quantitative agreement with the experiment, even though matter waves with wavelengths two orders of magnitude smaller than the healing length are present. In these experiments, no significant heating or particle loss is observed.Comment: 7 pages, 7 figure