Entanglement dynamics of two independent Jaynes-Cummings atoms without rotating-wave approximation

Entanglement evolution of two independent Jaynes-Cummings atoms without rotating-wave approximation (RWA) is studied by an numerically exact approach. The previous results in the RWA are essentially modified in the strong coupling regime ($g\ge 0.1$), which has been reached in the recent experiments on the flux qubit coupled to the LC resonator. For the initial Bell state with anti-correlated spins, the entanglement sudden death (ESD) is absent in the RWA, but does appear in the present numerical calculation without RWA. Aperiodic entanglement evolution in the strong coupling regime is observed. The strong atom-cavity coupling facilitates the ESD. The sign of detuning play a essential role in the entanglement evolution for strong coupling, which is irrelevant in the RWA. An analytical results based on an unitary transformation are also given, which could not modify the RWA picture essentially. It is suggested that the activation of the photons may be the origin of the ESD. The present theoretical results could be applied to artificial atoms realized in recent experiments.Comment: 16 pages, 8 figure

Preparation of GHZ states via Grover's quantum searching algorithm

In this paper we propose an approach to prepare GHZ states of an arbitrary multi-particle system in terms of Grover's fast quantum searching algorithm. This approach can be regarded as an extension of the Grover's algorithm to find one or more items in an unsorted database.Comment: 9 pages, Email address: [email protected]

Testing the Bell Inequality at Experiments of High Energy Physics

Besides using the laser beam, it is very tempting to directly testify the Bell inequality at high energy experiments where the spin correlation is exactly what the original Bell inequality investigates. In this work, we follow the proposal raised in literature and use the successive decays $J/\psi\to\gamma\eta_c\to \Lambda\bar\Lambda\to p\pi^-\bar p\pi^+$ to testify the Bell inequality. Our goal is twofold, namely, we first make a Monte-Carlo simulation of the processes based on the quantum field theory (QFT). Since the underlying theory is QFT, it implies that we pre-admit the validity of quantum picture. Even though the QFT is true, we need to find how big the database should be, so that we can clearly show deviations of the correlation from the Bell inequality determined by the local hidden variable theory. There have been some critiques on the proposed method, so in the second part, we suggest some improvements which may help to remedy the ambiguities indicated by the critiques. It may be realized at an updated facility of high energy physics, such as BES III.Comment: 16 pages, 5 figure

Aptamer therapeutics: the 21st century\u27s magic bullet of nanomedicine

Aptamers, also known as chemical antibodies, are short single-stranded DNA, RNA or peptide molecules. These molecules can fold into complex three-dimensional structures and bind to target molecules with high affinity and specificity. The nucleic acid aptamers are selected from combinatorial libraries by an iterative in vitro selection procedure known as systematic evolution of ligands by exponential enrichment (SELEX). As a new class of therapeutics and drug targeting entities, bivalent and multivalent aptamer-based molecules are emerging as highly attractive alternatives to monoclonal antibodies as targeted therapeutics.Aptamers have several advantages, offering the possibility of overcoming limitations of antibodies: 1) they can be selected against toxic or non-immunogenic targets; 2) aptamers can be chemically modified by using modified nucleotides to enhance their stability in biological fluids or via incorporating reporter molecules, radioisotopes and functional groups for their detection and immobilization; 3) they have very low immunogenicity; 4) they display high stability at room temperature, in extreme pH, or solvent; 5) once selected, they can be chemically synthesized free from cell- culturederived contaminants, and they can be manufactured at any time, in large amounts, at relatively low cost and reproducibly; 6) they are smaller and thus can diffuse more rapidly into tissues and organs, leading to faster targeting in drug delivery; 7) they have lower molecular weight that can lead to faster body clearance, resulting in a low background noise for imaging and minimizing the radiation dose to the patient in diagnostic imaging. Thus, the high selectivity and sensitivity, ease of screening and production, chemical versatility as well as stability make aptamers a class of highly attractive agents for the development of novel therapeutics, targeted drug delivery vehicles and molecular imaging.In the review, we will discuss the latest technological advances in developing aptamers, its application as a novel class of drug on its own, as well as in surface functionalization of both polymer nanoparticles or nanoliposomes in the treatment of cancer, viral and autoimmune diseases

Clavicular stress fracture in a cricket fast bowler: A case report

<p>Abstract</p> <p>Introduction</p> <p>Whilst rare, stress fractures of the clavicle have been described in other sports. To our knowledge, this is the first reported case of a stress fracture of the clavicle occurring in a cricket fast bowler.</p> <p>Case presentation</p> <p>A 23-year-old professional cricket fast bowler presented with activity related shoulder pain. Imaging demonstrated a stress fracture of the lateral third of the clavicle. This healed with rest and rehabilitation allowing a full return to professional sport.</p> <p>Conclusion</p> <p>This injury is treated with activity modification and technique adaptation. In a professional sportsman, this needs to be recognised early so that return to play can be as quick as possible.</p

Gate-tunable Veselago Interference in a Bipolar Graphene Microcavity

The relativistic charge carriers in monolayer graphene can be manipulated in manners akin to conventional optics (electron-optics): angle-dependent Klein tunneling collimates an electron beam (analogous to a laser), while a Veselago refraction process focuses it (analogous to an optical lens). Both processes have been previously investigated, but the collimation and focusing efficiency have been reported to be relatively low even in state-of-the-art ballistic pn-junction devices. These limitations prevented the realization of more advanced quantum devices based on electron-optical interference, while understanding of the underlying physics remains elusive. Here, we present a novel device architecture of a graphene microcavity defined by carefully-engineered local strain and electrostatic fields. We create a controlled electron-optic interference process at zero magnetic field as a consequence of consecutive Veselago refractions in the microcavity and provide direct experimental evidence through low-temperature electrical transport measurements. The experimentally observed first-, second-, and third-order interference peaks agree quantitatively with the Veselago physics in a microcavity. In addition, we demonstrate decoherence of the interference by an external magnetic field, as the cyclotron radius becomes comparable to the interference length scale. For its application in electron-optics, we utilize Veselago interference to localize uncollimated electrons and characterize its contribution in further improving collimation efficiency. Our work sheds new light on relativistic single-particle physics and provides important technical improvements toward next-generation quantum devices based on the coherent manipulation of electron momentum and trajectory

Peptidyl-prolyl cis-trans isomerases (immunophilins) and their roles in parasite biochemistry, host-parasite interaction and antiparasitic drug action.

Immunophilin is the collective name given to the cyclophilin and FK506-binding protein (FKBP) families. As the name suggests, these include the major binding proteins of certain immunosuppressive drugs: cyclophilins for the cyclic peptide cyclosporin A and FKBPs for the macrolactones FK506 and rapamycin. Both families, although dissimilar in sequence, possess peptidyl-prolyl &lt;i&gt;cis-trans&lt;/i&gt; isomerase activity in vitro and can play roles in protein folding and transport, RNA splicing and the regulation of multiprotein complexes in cells. In addition to enzymic activity, many immunophilins act as molecular chaperones. This property may be conferred by the isomerase domain and/or by additional domains. Recent years have seen a great increase in the number of known immunophilin genes in parasitic protozoa and helminths and in many cases their products have been characterized biochemically and their temporal and spatial expression patterns have been examined. Some of these genes represent novel types: one example is a &lt;i&gt;Toxoplasma gondii&lt;/i&gt; gene encoding a protein with both cyclophilin and FKBP domains. Likely roles in protein folding and oligomerisation, RNA splicing and sexual differentiation have been suggested for parasite immunophilins. In addition, unexpected roles in parasite virulence (Mip FKBP of &lt;i&gt;Trypanosoma cruzi&lt;/i&gt;) and host immuno-modulation (e.g. 18-kDa cyclophilin of &lt;i&gt;Toxoplasma gondii&lt;/i&gt;) have been established. Furthermore, in view of the potent antiparasitic activities of cyclosporins, macrolactones and nonimmunosuppressive derivatives of these compounds, immunophilins may mediate drug action and/or may themselves represent potential drug targets. Investigation of the mechanisms of action of these agents may lead to the design of potent and selective antimalarial and other antiparasitic drugs. This review discusses the properties of immunophilins in parasites and the 'animal model' &lt;i&gt;Caenorhabditis elegans&lt;/i&gt; and relates these to our understanding of the roles of these proteins in cellular biochemistry, host-parasite interaction and the antiparasitic mechanisms of the drugs that bind to them

(Micro)evolutionary changes and the evolutionary potential of bird migration

Seasonal migration is the yearly long-distance movement of individuals between their breeding and wintering grounds. Individuals from nearly every animal group exhibit this behavior, but probably the most iconic migration is carried out by birds, from the classic V-shape formation of geese on migration to the amazing nonstop long-distance flights undertaken by Arctic Terns Sterna paradisaea. In this chapter, we discuss how seasonal migration has shaped the field of evolution. First, this behavior is known to turn on and off quite rapidly, but controversy remains concerning where this behavior first evolved geographically and whether the ancestral state was sedentary or migratory (Fig. 7.1d, e). We review recent work using new analytical techniques to provide insight into this topic. Second, it is widely accepted that there is a large genetic basis to this trait, especially in groups like songbirds that migrate alone and at night precluding any opportunity for learning. Key hypotheses on this topic include shared genetic variation used by different populations to migrate and only few genes being involved in its control. We summarize recent work using new techniques for both phenotype and genotype characterization to evaluate and challenge these hypotheses. Finally, one topic that has received less attention is the role these differences in migratory phenotype could play in the process of speciation. Specifically, many populations breed next to one another but take drastically different routes on migration (Fig. 7.2). This difference could play an important role in reducing gene flow between populations, but our inability to track most birds on migration has so far precluded evaluations of this hypothesis. The advent of new tracking techniques means we can track many more birds with increasing accuracy on migration, and this work has provided important insight into migration's role in speciation that we will review here