Enhancement of Persistent Currents by Hubbard Interactions In Disordered 1D Rings: Avoided Level Crossings Interpretation

We study effects of local electron interactions on the persistent current of one dimensional disordered rings. For different realizations of disorder we compute the current as a function of Aharonov-Bohm flux to zeroth and first orders in the Hubbard interaction. We find that the persistent current is {\em enhanced} by onsite interactions. Using an avoided level crossings approach, we derive analytic formulas which explain the numerical results at weak disorder. The same approach also explains the opposite effect (suppression) found for spinless fermion models with intersite interactions.Comment: uuencoded: 17 pages, text in revtex, 7 figs in postscrip

Floquet Spectrum and Transport Through an Irradiated Graphene Ribbon

Graphene subject to a spatially uniform, circularly-polarized electric field supports a Floquet spectrum with properties akin to those of a topological insulator, including non-vanishing Chern numbers associated with bulk bands and current-carrying edge states. Transport properties of this system however are complicated by the non-equilibrium occupations of the Floquet states. We address this by considering transport in a two-terminal ribbon geometry for which the leads have well-defined chemical potentials, with an irradiated central scattering region. We demonstrate the presence of edge states, which for infinite mass boundary conditions may be associated with only one of the two valleys. At low frequencies, the bulk DC conductivity near zero energy is shown to be dominated by a series of states with very narrow anticrossings, leading to super-diffusive behavior. For very long ribbons, a ballistic regime emerges in which edge state transport dominates.Comment: 4.2 pages, 3 figure

Oscillating Superfluidity of Bosons in Optical Lattices

We follow up on a recent suggestion by C. Orzel et. al., Science, 291, 2386 (2001), whereby bosons in an optical lattice would be subjected to a sudden parameter change from the Mott to the superfluid phase. We analyze the Bose Hubbard model with a modified coherent states path integral which can escribe - both - phases. The saddle point theory yields collective oscillations of the uniform superfluid order parameter. These would be seen in time resolved interference patterns made by the released gas. We calculate the collective oscillation's damping rate by phason pair emission. In two dimensions the overdamped region largely overlaps with the quantum critical region. Measurements of critical dynamics on the Mott side are proposed.Comment: 4 pages 1 eps figures; Final version as appears in PRL. Added discussion on spontaneous generation of vortice

Perbandingan Pengukuran Tekanan Darah Pada Lengan Kiri Dan Lengan Kanan Pada Penderita Hipertensi Di Ruangan Irina C Blu Rsup Prof. Dr. R. D. Kandou Manado

: Differences of blood pressure on left or right arm can be caused by several factors, including age factor, vascular occlusion, peripheral vascular disease, and heart problems. The purpose of this study was to determine the ratio of blood pressure measurements on the left arm and right arm in patients with hypertension. The research method used was descriptive analityc. The sampling technique used was accidental sampling, with the number of samples 31 respondents in room Irina C BLU RSUP Prof. Dr. R. D. Kandou Manado. With SPSS (Statistic Program for Science) used Wilcoxon signed test, at the 95% significance level (α =0.05), showed the value of p=0.034 (<0.05). This research was carried out three times measurements one ach respondent obtain and average value of measurements on the left arm of 2.9032 and 2.7097 on the right arm. The conclusion: There is a difference between the blood pressure measurement results on left arm and right arm in patients with hypertension

Testing for Majorana Zero Modes in a Px+iPy Superconductor at High Temperature by Tunneling Spectroscopy

Directly observing a zero energy Majorana state in the vortex core of a chiral superconductor by tunneling spectroscopy requires energy resolution better than the spacing between core states $\Delta^2/eF$. We show that nevertheless, its existence can be decisively tested by comparing the temperature broadened tunneling conductance of a vortex with that of an antivortex even at temperatures $T >> \Delta^2/eF$.Comment: 5 pages, 4 figure

Majorana fermions of a two-dimensional Px+iPy superconductor

To investigate Majorana fermionic excitations of a $p_x+ip_y$ superconductor, the Bogoliubov-de-Gennes equation is solved on a sphere for two cases: (i) a vortex-antivortex pair at opposite poles and (ii) an edge near the south pole and an antivortex at the north pole. The vortex cores support a state of two Majorana fermions, the energy of which decreases exponentially with the radius of the sphere, independently of a moderate disorder potential. The tunneling conductance of an electron into the superconductor near the position of a vortex is computed for finite temperature, and is compared to the case of an {\it s}-wave superconductor. The zero bias conductance peak of the antivortex is half that of the vortex. This effect can be used as a probe of the order parameter symmetry, and as a direct measurement of the Majorana fermion.Comment: 15 pages, 17 figure

Gambaran Kadar Apolipoprotein B (APO-B) Serum Pada Vegetarian Lacto-ovo

: Lacto-ovo vegetarian is the most common type of vegetarians in society. This type of vegetarian does not consume fish and meats, except eggs, milk, and its products. Apolipoprotein is a protein component of lipoprotein. Plasma lipoprotein is a complex macromolecule with a spherical form consists of specific lipid and protein. Apolipoprotein B (APO-B) is a main apolipoprotein in low density lipoprotein (LDL). It is also found in very low density lipoprotein (VLDL) and chylomicron. This study was aimed to obtain the description of serum apolipoprotein B (APO-B) levels in lacto-ovo vegetarians. This was a descriptive study with a cross sectional design. There were 15 respondents from Vihara Mandalatama Matreiya Manado obtained by using total sampling method. The results showed that 8 respondents (53.3%) had normal serum APO-B levels, 4 respondents (26.6%) had low serum APO-B levels, and 3 respondents (20%) had high serum APO-B levels. Conclusion: The majority of lacto-ovo vegetarians had normal levels of serum apolipoprotein B