Two-orbital SU(N) magnetism with ultracold alkaline-earth atoms

Fermionic alkaline-earth atoms have unique properties that make them attractive candidates for the realization of novel atomic clocks and degenerate quantum gases. At the same time, they are attracting considerable theoretical attention in the context of quantum information processing. Here we demonstrate that when such atoms are loaded in optical lattices, they can be used as quantum simulators of unique many-body phenomena. In particular, we show that the decoupling of the nuclear spin from the electronic angular momentum can be used to implement many-body systems with an unprecedented degree of symmetry, characterized by the SU(N) group with N as large as 10. Moreover, the interplay of the nuclear spin with the electronic degree of freedom provided by a stable optically excited state allows for the study of spin-orbital physics. Such systems may provide valuable insights into strongly correlated physics of transition metal oxides, heavy fermion materials, and spin liquid phases.Comment: 15 pages, 10 figures. V2: extended experimental accessibility and Kondo sections in the main text (including new Fig. 5b) and in the Methods; reorganized other parts; added reference

Entanglement Entropy of 3-d Conformal Gauge Theories with Many Flavors

Three-dimensional conformal field theories (CFTs) of deconfined gauge fields coupled to gapless flavors of fermionic and bosonic matter describe quantum critical points of condensed matter systems in two spatial dimensions. An important characteristic of these CFTs is the finite part of the entanglement entropy across a circle. The negative of this quantity is equal to the finite part of the free energy of the Euclidean CFT on the three-sphere, and it has been proposed to satisfy the so called F-theorem, which states that it decreases under RG flow and is stationary at RG fixed points. We calculate the three-sphere free energy of non-supersymmetric gauge theory with a large number N_F of bosonic and/or fermionic flavors to the first subleading order in 1/N_F. We also calculate the exact free energies of the analogous chiral and non-chiral {\cal N} = 2 supersymmetric theories using localization, and find agreement with the 1/N_F expansion. We analyze some RG flows of supersymmetric theories, providing further evidence for the F-theorem.Comment: 31 pages, 2 figures; v2 refs added, minor change

Hyperhomocysteinemia is independently associated with albuminuria in the population-based CoLaus study

<p>Abstract</p> <p>Background</p> <p>Increased serum levels of homocysteine and uric acid have each been associated with cardiovascular risk. We analyzed whether homocysteine and uric acid were associated with glomerular filtration rate (GFR) and albuminuria independently of each other. We also investigated the association of <it>MTHFR </it>polymorphisms related to homocysteine with albuminuria to get further insight into causality.</p> <p>Methods</p> <p>This was a cross-sectional population-based study in Caucasians (<it>n </it>= 5913). Hyperhomocysteinemia was defined as total serum homocysteine ≥ 15 μmol/L. Albuminuria was defined as urinary albumin-to-creatinine ratio > 30 mg/g.</p> <p>Results</p> <p>Uric acid was associated positively with homocysteine (r = 0.246 in men and r = 0.287 in women, <it>P </it>< 0.001). The prevalence of albuminuria increased across increasing homocysteine categories (from 6.4% to 17.3% in subjects with normal GFR and from 3.5% to 14.5% in those with reduced GFR, <it>P </it>for trend < 0.005). Hyperhomocysteinemia (OR = 2.22, 95% confidence interval: 1.60-3.08, <it>P </it>< 0.001) and elevated serum uric acid (OR = 1.27, 1.08-1.50, per 100 μmol/L, <it>P </it>= 0.004) were significantly associated with albuminuria, independently of hypertension and type 2 diabetes. The 2-fold higher risk of albuminuria associated with hyperhomocysteinemia was similar to the risk associated with hypertension or diabetes. <it>MTHFR </it>alleles related to higher homocysteine were associated with increased risk of albuminuria.</p> <p>Conclusions</p> <p>In the general adult population, elevated serum homocysteine and uric acid were associated with albuminuria independently of each other and of renal function.</p

Arabidopsis R-SNARE Proteins VAMP721 and VAMP722 Are Required for Cell Plate Formation

Background: Cell plate formation during plant cytokinesis is facilitated by SNARE complex-mediated vesicle fusion at the cell-division plane. However, our knowledge regarding R-SNARE components of membrane fusion machinery for cell plate formation remains quite limited. Methodology/Principal Findings: We report the in vivo function of Arabidopsis VAMP721 and VAMP722, two closely sequence-related R-SNAREs, in cell plate formation. Double homozygous vamp721vamp722 mutant seedlings showed lethal dwarf phenotypes and were characterized by rudimentary roots, cotyledons and hypocotyls. Furthermore, cell wall stubs and incomplete cytokinesis were frequently observed in vamp721vamp722 seedlings. Confocal images revealed that green fluorescent protein-tagged VAMP721 and VAMP722 were preferentially localized to the expanding cell plates in dividing cells. Drug treatments and co-localization analyses demonstrated that punctuate organelles labeled with VAMP721 and VAMP722 represented early endosomes overlapped with VHA-a1-labeled TGN, which were distinct from Golgi stacks and prevacuolar compartments. In addition, protein traffic to the plasma membrane, but not to the vacuole, was severely disrupted in vamp721vamp722 seedlings by subcellular localization of marker proteins. Conclusion/Significance: These observations suggest that VAMP721 and VAMP722 are involved in secretory trafficking to the plasma membrane via TGN/early endosomal compartment, which contributes substantially to cell plate formatio