Entanglement and quantum correlations in the XX spin-1/21/2 honeycomb lattice

The ground state phase diagram of the dimerized spin-1/2 XX honeycomb model in presence of a transverse magnetic field (TF) is known. With the absence of the magnetic field, two quantum phases, namely, the N\'eel and the dimerized phases have been identified. Moreover, canted N\'eel and the paramagnetic (PM) phases also emerge by applying the magnetic field. In this paper, using two complementary numerical exact techniques, Lanczos exact diagonalization, and Density matrix renormalization group (DMRG) methods, we study this model by focusing on the quantum correlations, the concurrence, and the quantum discord (QD) among nearest-neighbor spins. We show that the quantum correlations can capture the position of the quantum critical points in the whole range of the ground state phase diagram consistent with previous results. Although the concurrence and the QD are short-range, informative about long-ranged critical correlations. In addition, we address a "magnetic-entanglement" behavior that starts from an entangled field around the saturation field.Comment: 8 pages, 5 figure

Fermions in non-relativistic AdS/CFT correspondence

We extend the non-relativistic AdS/CFT correspondence to the fermionic fields. In particular we study the two point function of a fermionic operator in non-relativistic CFTs by making use of a massive fermion propagating in geometries with Schrodinger group isometry. Although the boundary of the geometries with Schrodinger group isometry differ from that in AdS geometries where the dictionary of AdS/CFT is established, using the general procedure of AdS/CFT correspondence, we see that the resultant two point function has the expected form for fermionic operators in non-relativistic CFTs, though a non-trivial regularization may be needed.Comment: 12 pages,Latex file; V2: typos corrected, refs adde

Design and Study of the Efflux Function of the EGFP Fused MexAB-OprM Membrane Transporter in Pseudomonas aeruginosa Using Spectroscopy

Multidrug membrane transporters (efflux pumps) can selectively extrude a variety of structurally and functionally diverse substrates (e.g., chemotoxics, antibiotics), leading to multidrug resistance (MDR) and ineffective treatment of a wide variety of diseases. In this study, we have designed and constructed a fusion gene (egfp-mexB) of N-terminal mexB with C-terminal egfp, inserted it into a plasmid vector (pMMB67EH), and successfully expressed it in the Δ MexB (MexB deletion) strain of Pseudomonas aeruginosato create a new strain that expresses MexA-(EGFP-MexB)-OprM. We characterized the fusion gene using gel electrophoresis and DNA sequencing, and determined its expression in live cells by measuring the fluorescence of EGFP in single live cells using fluorescence microscopy. Efflux function of the new strain was studied by measuring its accumulation kinetics of ethidium bromide (EtBr, a pump substrate) using fluorescence spectroscopy, which was compared with cells (WT, ΔMexM, ΔABM, and nalB1) with various expression levels of MexAB-OprM. The new strain shows 6-fold lower accumulation rates of EtBr (15 μM) than ΔABM, 4-fold lower than ΔMexB, but only 1.1-fold higher than WT. As the EtBr concentration increases to 40 mM, the new strain has nearly the same accumulation rate of EtBr as ΔMexB, but 1.4-fold higher than WT. We observed the nearly same level of inhibitory effect of CCCP (carbonyl cyanide-m-chlorophenylhydrazone) on the efflux of EtBr by the new strain and WT. Antibiotic susceptibility study shows that the minimum inhibitory concentrations (MICs) of aztreonam (AZT) and chloramphenicol (CP) for the new strain are 6-fold or 3-fold lower than WT, respectively, and 2-fold higher than those of Δ MexB. Taken together, the results suggest that the fusion protein partially retains the efflux function of MexAB-OprM. The modeled structure of the fusion protein shows that the position and orientation of the N-terminal fused EGFP domain may either partially block the translocation pore or restrict the movement of the individual pump domains, which may lead to partially restricted efflux activity

Thomas-Fermi Model in the Presence of Natural Cutoffs

It has been revealed, in the context of quantum gravity candidates, that measurement of position cannot be done with arbitrary precision and there is a finite resolution of space-time points. This leads naturally to a minimal measurable length of the order of Planck length. Also, in the context of newly proposed doubly special relativity theories, a test particle’s momentum cannot be arbitrarily imprecise leading nontrivially to a maximal momentum for a test particle. These two natural cutoffs affects most of quantum field theoretic arguments in the spirit of condensed matter physics. Here we focus on the role of these natural cutoffs on Thomas-Fermi theory in condensed matter physics. We show how quantum gravity effects can play important role phenomenologically in many-body interactions of solids

Lowest Order Constrained Variational calculation for Polarized Liquid 3He at Finite Temperature

We have investigated some of the thermodynamic properties of spin polarized liquid $^3\mathrm{He}$ at finite temperature using the lowest order constrained variational method. For this system, the free energy, entropy and pressure are calculated for different values of the density, temperature and polarization. We have also presented the dependence of specific heat, saturation density and incompressibility on the temperature and polarization.Comment: 17 pages, 7 figures. Int. J. Mod. Phys. B 27 (2008) in pres

New combined PIC-MCC approach for fast simulation of a radio frequency discharge at low gas pressure

A new combined PIC-MCC approach is developed for accurate and fast simulation of a radio frequency discharge at low gas pressure and high density of plasma. Test calculations of transition between different modes of electron heating in a ccrf discharge in helium and argon show a good agreement with experimental data. We demonstrate high efficiency of the combined PIC-MCC algorithm, especially for the collisionless regime of electron heating.Comment: 6 paged, 8 figure