Probing quench dynamics across a quantum phase transition into a 2D Ising antiferromagnet

Simulating the real-time evolution of quantum spin systems far out of equilibrium poses a major theoretical challenge, especially in more than one dimension. We experimentally explore the dynamics of a two-dimensional Ising spin system with transverse and longitudinal fields as we quench it across a quantum phase transition from a paramagnet to an antiferromagnet. We realize the system with a near unit-occupancy atomic array of over 200 atoms obtained by loading a spin-polarized band insulator of fermionic lithium into an optical lattice and induce short-range interactions by direct excitation to a low-lying Rydberg state. Using site-resolved microscopy, we probe the correlations in the system after a sudden quench from the paramagnetic state and compare our measurements to exact calculations in the regime where it is possible. We achieve many-body states with longer-range antiferromagnetic correlations by implementing a near-adiabatic quench and study the buildup of correlations as we cross the quantum phase transition at different rates

Modulation of L-arginine-induced acute pancreatitis by meloxicam and/or L-carnitine in rats

Background: Acute pancreatitis (AP) is an inflammatory disease, where oxidative stress, subsequently inflammatory mediators activation play a pivotal role. Currently, no definite treatment exists and therapy is mainly supportive that directed to inhibit local pancreatic injury and systemic inflammatory complications. This study is presented to explore whether anti-inflammatory and/or antioxidant drug could ameliorate L-arginine-induced AP.Methods: Rats were sub-grouped randomly into five groups. Control group, AP was provoked by a single intraperitoneal injection of L-arginine (250 mg/100g), rat treated with meloxicam (4 mg/kg, IP), animals treated with L-carnitine (500 mg/kg, IP), and rats were treated with both meloxicam and L-carnitine. All treatments were once daily for 7 consecutive days and started 1 hr later after L-arginine administration. Serum and tissues samples were prepared for biochemical analysis. Histopathological examination for the other pancreatic tissues was done.Results: L-arginine significantly elevated serum activity of amylase and lipase enzymes, while notably reduced serum calcium level. Moreover, L-arginine markedly increased the pancreatic tissues content of tumor necrosis factor-α, malondialdehyde, and nitric oxide. In addition, L-arginine significantly increased pancreatic activity of myeloperoxidase, while markedly depleted glutathione level. Treatment with either meloxicam or L-carnitine significantly attenuated L-arginine-induced biochemical changes. On the other hand, co-administration of both meloxicam and carnitine has an ameliorative effect greater than each drug alone.Conclusion: Treatment with both meloxicam and L-carnitine is a more effective than each of them alone which is attributed to augmentation their antioxidant, anti‑inflammatory effects

Single-particle-sensitive imaging of freely propagating ultracold atoms

We present a novel imaging system for ultracold quantum gases in expansion. After release from a confining potential, atoms fall through a sheet of resonant excitation laser light and the emitted fluorescence photons are imaged onto an amplified CCD camera using a high numerical aperture optical system. The imaging system reaches an extraordinary dynamic range, not attainable with conventional absorption imaging. We demonstrate single-atom detection for dilute atomic clouds with high efficiency where at the same time dense Bose-Einstein condensates can be imaged without saturation or distortion. The spatial resolution can reach the sampling limit as given by the 8 \mu m pixel size in object space. Pulsed operation of the detector allows for slice images, a first step toward a 3D tomography of the measured object. The scheme can easily be implemented for any atomic species and all optical components are situated outside the vacuum system. As a first application we perform thermometry on rubidium Bose-Einstein condensates created on an atom chip.Comment: 24 pages, 10 figures. v2: as publishe

A numerical 1.5D method for the rapid simulation of geophysical resistivity measurements

In some geological formations, borehole resistivity measurements can be simulated using a sequence of 1D models. By considering a 1D layered media, we can reduce the dimensionality of the problem from 3D to 1.5D via a Hankel transform. The resulting formulation is often solved via a semi-analytic method, mainly due to its high performance. However, semi-analytic methods have important limitations such as, for example, their inability to model piecewise linear variations on the resistivity. Herein, we develop a multi-scale finite element method (FEM) to solve the secondary field formulation. This numerical scheme overcomes the limitations of semi-analytic methods while still delivering high performance. We illustrate the performance of the method with numerical synthetic examples based on two symmetric logging-while-drilling (LWD) induction devices operating at 2 MHz and 500 KHz, respectively

Mixed-Ligand Complexes of Fe(II) & Cu(II) with Alizarin Maroon as a Primary Ligand & 5-Sulphosalicylic Acid as a Secondary Ligand

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Booster cavity and fundamental power coupler design issues for bERLinPro

HZB has started building the 50 MeV, 100mA demonstrator energy recovery linac ERL facility bERLinPro. The high power injector system needs to deliver this beam at 6.5 MeV by combining the energy gain of a 1.4 cell SRF photo injector and three Cornell style 2 cell booster cavities. One booster cavity will be operated at zero crossing for bunch energy chirping. Thus two booster cavities have to deliver 2MV each requiring a strong coupling with a loaded Q of 105. To house the two envisaged KEK fundamental power couplers FPC with the cavity, the geometry was slightly modified. Further, to increase coupling and reduce transverse kick effects to the beam, a golf tee antenna tip was designed. This paper summarizes the SRF challenges for the booster cavities, the operational conditions and the modification to the KEK couplers, including tracking calculations to estimate the coupler kick effect to higher orde

Hybrid 2D surface trap for quantum simulation

We demonstrate a novel optical trapping scheme for ultracold atoms. Using a combination of evanescent wave, standing wave, and magnetic potentials we create a deeply 2D Bose-Einstein condensate (BEC) at a few microns from a glass surface. Using techniques such as broadband "white" light to create evanescent and standing waves, we realize a smooth potential with a trap frequency aspect ratio of 300:1:1 and long lifetimes. This makes the setup suitable for many-body quantum simulations and applications such as high precision measurements close to surfaces.Comment: 5 pages, 4 figure

Lattice dynamical signature of charge density wave formation in underdoped YBa2Cu3O6+x

We report a detailed Raman scattering study of the lattice dynamics in detwinned single crystals of the underdoped high temperature superconductor YBa2Cu3O6+x (x=0.75, 0.6, 0.55 and 0.45). Whereas at room temperature the phonon spectra of these compounds are similar to that of optimally doped YBa2Cu3O6.99, additional Raman-active modes appear upon cooling below ~170-200 K in underdoped crystals. The temperature dependence of these new features indicates that they are associated with the incommensurate charge density wave state recently discovered using synchrotron x-ray scattering techniques on the same single crystals. Raman scattering has thus the potential to explore the evolution of this state under extreme conditions.Comment: 12 pages, 11 figure