Introduction: contains Cover, Table of Contents, Letter from the Editor, and Masthead

I hope you enjoy the third issue of the Richmond Journal of Law and Technology for the 2006-2007 academic year, our Annual Survey of Electronic Discovery. This is our first annual survey since the new amendments to the Federal Rules of Civil Procedure, which at the time of this publication have been in effect for several months, that affect electronic discovery in several significant ways. The entire staff of the Journal has worked diligently to bring these articles to our readers. Whether you are new to the Journal and electronic discovery, or whether you are a long-time reader, you will find the observations that follow enlightening

Probing topology by "heating": Quantized circular dichroism in ultracold atoms

We reveal an intriguing manifestation of topology, which appears in the depletion rate of topological states of matter in response to an external drive. This phenomenon is presented by analyzing the response of a generic 2D Chern insulator subjected to a circular time-periodic perturbation: due to the system's chiral nature, the depletion rate is shown to depend on the orientation of the circular shake. Most importantly, taking the difference between the rates obtained from two opposite orientations of the drive, and integrating over a proper drive-frequency range, provides a direct measure of the topological Chern number of the populated band ($\nu$): this "differential integrated rate" is directly related to the strength of the driving field through the quantized coefficient $\eta_0\!=\!\nu /\hbar^2$. Contrary to the integer quantum Hall effect, this quantized response is found to be non-linear with respect to the strength of the driving field and it explicitly involves inter-band transitions. We investigate the possibility of probing this phenomenon in ultracold gases and highlight the crucial role played by edge states in this effect. We extend our results to 3D lattices, establishing a link between depletion rates and the non-linear photogalvanic effect predicted for Weyl semimetals. The quantized circular dichroism revealed in this work designates depletion-rate measurements as a universal probe for topological order in quantum matter.Comment: 10 pages, 5 figures (including Sup. Mat.). Revised version, accepted for publicatio

Oxygen isotope equilibrium in brachiopod shell fibres in the context of biological control

No abstract available

Rydberg-Atom Quantum Simulation and Chern Number Characterization of a Topological Mott Insulator

In this work we consider a system of spinless fermions with nearest and next-to-nearest neighbor repulsive Hubbard interactions on a honeycomb lattice, and propose and analyze a realistic scheme for analog quantum simulation of this model with cold atoms in a two-dimensional hexagonal optical lattice. To this end, we first derive the zero-temperature phase diagram of the interacting model within a mean-field theory treatment. We show that besides a semi-metallic and a charge-density-wave ordered phase, the system exhibits a quantum anomalous Hall phase, which is generated dynamically, i.e. purely as a result of the repulsive fermionic interactions and in the absence of any external gauge fields. We establish the topological nature of this dynamically created Mott insulating phase by the numerical calculation of a Chern number. Based on the knowledge of the mean-field phase diagram, we then discuss in detail how the interacting Hamiltonian can be engineered effectively by state-of-the-art experimental techniques for laser-dressing of cold fermionic ground-state atoms with electronically excited Rydberg states that exhibit strong dipolar interactions.Comment: Revtex4 file, color figures. Final journal version. References update

Detection of Zak phases and topological invariants in a chiral quantum walk of twisted photons

Topological insulators are fascinating states of matter exhibiting protected edge states and robust quantized features in their bulk. Here, we propose and validate experimentally a method to detect topological properties in the bulk of one-dimensional chiral systems. We first introduce the mean chiral displacement, and we show that it rapidly approaches a multiple of the Zak phase in the long time limit. Then we measure the Zak phase in a photonic quantum walk, by direct observation of the mean chiral displacement in its bulk. Next, we measure the Zak phase in an alternative, inequivalent timeframe, and combine the two windings to characterize the full phase diagram of this Floquet system. Finally, we prove the robustness of the measure by introducing dynamical disorder in the system. This detection method is extremely general, as it can be applied to all one-dimensional platforms simulating static or Floquet chiral systems.Comment: 10 pages, 7 color figures (incl. appendices) Close to the published versio

Quantum anomalous Hall phase in synthetic bilayers via twistronics without a twist

We recently proposed quantum simulators of "twistronic-like" physics based on ultracold atoms and syntheticdimensions [Phys. Rev. Lett. 125, 030504 (2020)]. Conceptually, the scheme is based on the idea that aphysical monolayer optical lattice of desired geometry is upgraded to a synthetic bilayer system by identifyingthe internal states of the trapped atoms with synthetic spatial dimensions. The couplings between the internalstates, i.e. between sites on the two layers, can be exquisitely controlled by laser induced Raman transitions.By spatially modulating the interlayer coupling, Moir\'e-like patterns can be directly imprinted on the latticewithout the need of a physical twist of the layers. This scheme leads practically to a uniform pattern across thelattice with the added advantage of widely tunable interlayer coupling strengths. The latter feature facilitates theengineering of flat bands at larger "magic" angles, or more directly, for smaller unit cells than in conventionaltwisted materials. In this paper we extend these ideas and demonstrate that our system exhibits topologicalband structures under appropriate conditions. To achieve non-trivial band topology we consider imanaginarynext-to-nearest neighbor tunnelings that drive the system into a quantum anomalous Hall phase. In particular,we focus on three groups of bands, whose their Chern numbers triplet can be associated to a trivial insulator(0,0,0), a standard non-trivial (-1,0,1) and a non-standard non-trivial (-1,1,0). We identify regimes of parameterswhere these three situations occur. We show the presence of an anomalous Hall phase and the appearance oftopological edge states. Our works open the path for experiments on topological effects in twistronics without atwistComment: 11 pages, 10 figure

Association of Plasmid Bearing Multi Drug Resistant Bacteria with High Mortalities in Nigerian Poultry

Bacteriological investigations were carried out on reported cases of low and high mortalities in commercial poultry in the year 2007-2009 in commercial flocks of breeders, layers, broilers, chicks and growers. Pure bacterial isolates obtained from dead birds, mainly Gram negative,  were tested for their biochemical and antibiotic susceptibility profiles using Microscan® Dried Gram-negative Breakpoint Combo Pannels. The microscan panel analysis bacterial isolates for 24 biochemical tests and up to 25 antimicrobial agents following 16-20 hours of incubation at 35-37oC. Bacteria isolated were Escherichia coli, Salmonella Enteritidis, Salmonella Pullorum, Salmonella Gallinarum, Citrobacter youngae, Klebsiella ozaneae, Klebsiella variicola, Enterobacter cloaceae, Hafnia alvei, Pasteurella gallinarum and Pasteurella multocida. The bacterial isolates showed resistance to 6-23 of the 25 antibiotics tested. Tetracycline and ampicilllin were found as the least potent drugs, with 90 and 90.91% resistance respectively. Resistance was obtained against antibacterial agents that are not in use in Nigerian poultry industry, such as the cephalosporins, carbapenems, piperacillin, tircacillin, amikacin, tobramcycin and levofloxacin suggesting possible genetic contribution to resistance. Thirty-four (85%) of the 40 pathogenic bacteria isolates treated for plasmid profile were found to be carrying plasmids. Plasmid DNA size 11.50 kbp was commonly observed (about 65%) among all the plasmid borne mdr bacteria, plasmid DNA size 10kbp (incidence of about 22% in plasmid borne bacteria) as well as a 26.3 kbp plasmid DNA and a 6.6 kbp plasmid DNA. The susceptibility of the plasmid bearing bacteria to antibiotics was enhanced following plasmid curing with sodium deodecyl sulphate.  Antibiotic susceptibility testing should guide treatment in all infections where organism can be cultured in veterinary medicine practice Keywords: Antibiotics, high mortalities, multi-drug resistant bacteria, plasmid, poultry