Quantized Quasi-Two Dimensional Bose-Einstein Condensates with Spatially Modulated Nonlinearity

We investigate the localized nonlinear matter waves of the quasi-two dimensional Bose-Einstein condensates with spatially modulated nonlinearity in harmonic potential. It is shown that the whole Bose-Einstein condensates, similar to the linear harmonic oscillator, can have an arbitrary number of localized nonlinear matter waves with discrete energies, which are mathematically exact orthogonal solutions of the Gross-Pitaevskii equation. Their novel properties are determined by the principle quantum number n and secondary quantum number l: the parity of the matter wave functions and the corresponding energy levels depend only on n, and the numbers of density packets for each quantum state depend on both n and l which describe the topological properties of the atom packets. We also give an experimental protocol to observe these novel phenomena in future experiments.Comment: 5 pages, 5 figure

Cooling mechanical resonators to quantum ground state from room temperature

Ground-state cooling of mesoscopic mechanical resonators is a fundamental requirement for test of quantum theory and for implementation of quantum information. We analyze the cavity optomechanical cooling limits in the intermediate coupling regime, where the light-enhanced optomechanical coupling strength is comparable with the cavity decay rate. It is found that in this regime the cooling breaks through the limits in both the strong and weak coupling regimes. The lowest cooling limit is derived analytically at the optimal conditions of cavity decay rate and coupling strength. In essence, cooling to the quantum ground state requires $Q_{\mathrm{m}}>2.4n_{\mathrm{th}}$, with $Q_{\mathrm{m}}$ being the mechanical quality factor and $n_{\mathrm{th}}$ being the thermal phonon number. Remarkably, ground-state cooling is achievable starting from room temperature, when mechanical $Q$-frequency product $Q_{\mathrm{m}}{\nu>1.5}\times10^{13}$, and both of the cavity decay rate and the coupling strength exceed the thermal decoherence rate. Our study provides a general framework for optimizing the backaction cooling of mesoscopic mechanical resonators

2,5-Dibromo­terephthalic acid dihydrate

The asymmetric unit of the title compound, C8H4Br2O4·2H2O, contains one half-mol­ecule of 2,5-dibromo­terephthalic acid (DBTA) and one water mol­ecule. The DBTA mol­ecule is centrosymmetric. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules, forming a three-dimensional framework

1-Diphenyl­phosphino-1′-(diphenyl­phosphinoyl)cobaltocenium hexa­fluorido­phosphate

The title compound, [Co(C17H14OP)(C17H14P)]PF6, was obtained unintentionally as the product of an attempted synthesis of [1,1′-bis­(oxodiphenyl­phospho­ranyl)cobaltocenium] hexa­fluorido­phosphate. The O atom of the oxo group is disordered over two positions with site occupancies of 0.65:0.35. The crystal structure contains weak inter­molecular C—H⋯F hydrogen bonds, connecting the components of the structure into chains parallel to [010]

Significance of the lipid profile and endothelium-dependent vasodilatation in the pathogenesis of microvascular angina

Background: To investigate the significance of lipid disorders and endothelial dysfunction in the pathogenesis of microvascular angina. Methods: Levels of plasma lipids, lipoproteins and apolipoproteins were assessed in 21 patients with microvascular angina and 24 healthy subjects as controls. Also, the endothelium-dependent vasodilatation function was determined with high-resolution ultrasound in both groups. Results: Levels of serum total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), apolipoprotein B100 (ApoB100) and lipoprotein(a) [Lp(a)] in microvascular angina group were significantly higher than those in healthy subjects (each p < 0.05). The flow-mediated dilatation (FMD) in brachial arteries in patients with microvascular angina declined significantly as compared with that in control subjects (4.7 &#177; 1.9% vs. 12.8 &#177; 3.7%, p < 0.001). However, no significant difference was observed in response to nitroglycerin between groups (19.7 &#177; 8.1% vs. 21.2 &#177; 6.6%; p > 0.05). Linear correlation analysis revealed a significant negative correlation between the FMD of brachial arteries and the serum levels of LDL-C and Lp(a) in the microvascular angina group (r = -0.5125 and -0.4271, respectively, both p < 0.001). Subsequently, all subjects were pooled and divided into two groups (groups A and B) according to the degree of FMD in brachial arteries (A &#163; 4% and B > 4%). The serum LDL-C level was found to be significantly higher in group A than in group B (4.09 &#177; 0.65 mmol/L vs. 2.59 &#177; 0.49 mmol/L; p < 0.05). Conclusions: Plasma lipid disorders and vascular endothelial dysfunction may play important roles in the development of microvascular angina. The dysfunction of endothelium-dependent vasodilation was mainly associated with anomalies in LDL-C and Lp(a), and myocardial endothelial dysfunction was aggravated by lipid abnormalities in patients with microvascular angina

Aqua­chloridobis(1,10-phenanthroline-κ2 N,N′)zinc(II) chloride N,N-dimethyl­formamide solvate

The Zn atom in the title salt, [ZnCl(C12H8N2)2(H2O)]Cl·C3H7NO, is chelated by two phenanthroline mol­ecules and is bonded to one chloride ion and one water mol­ecule, resulting in a ZnN4ClO octa­hedral coordination environment with the Cl and O atoms in a cis conformation. The cations and anions are linked by O—H⋯Cl hydrogen bonds across a center of inversion, forming a hydrogen-bonded dimeric association. The dimethyl­formamide solvent mol­ecule is disordered over two orientations in a 0.56 (1):0.44 (1) ratio

4-[(E)-(2-Methoxy­phen­yl)imino­meth­yl]-N,N-dimethyl­aniline

In the title compound, C16H18N2O, the dihedral angle between the benzene rings is 38.5 (2)°. The crystal packing is stabilized by weak C—H⋯N and C—H⋯O inter­actions and aromatic π–π stacking [centroid–centroid separations = 3.620 (5) and 3.546 (4) Å]