A comparison of the Bravyi-Kitaev and Jordan-Wigner transformations for the quantum simulation of quantum chemistry

The ability to perform classically intractable electronic structure calculations is often cited as one of the principal applications of quantum computing. A great deal of theoretical algorithmic development has been performed in support of this goal. Most techniques require a scheme for mapping electronic states and operations to states of and operations upon qubits. The two most commonly used techniques for this are the Jordan-Wigner transformation and the Bravyi-Kitaev transformation. However, comparisons of these schemes have previously been limited to individual small molecules. In this paper we discuss resource implications for the use of the Bravyi-Kitaev mapping scheme, specifically with regard to the number of quantum gates required for simulation. We consider both small systems which may be simulatable on near-future quantum devices, and systems sufficiently large for classical simulation to be intractable. We use 86 molecular systems to demonstrate that the use of the Bravyi-Kitaev transformation is typically at least approximately as efficient as the canonical Jordan-Wigner transformation, and results in substantially reduced gate count estimates when performing limited circuit optimisations.Comment: 46 pages, 11 figure

Pressure dependence of two-level systems in disordered atomic chain

The dependence of two-level systems in disordered atomic chain on pressure, both positive and negative was studied numerically. The disorder was produced through the use of interatomic pair potentials having more than one energy minimum. It was found that there exists a correlation between the energy separation of the minima of two-level systems Delta and the variation of this separation with pressure. The correlation may have either positive or negative sign, implying that the asymmetry of two-level systems may in average increase or decrease with pressure depending on the interplay of different interactions between atoms in disordered state. The values of Delta depend on the sign of pressure.Comment: 5 pages, 5 figure

Development of tsunami early warning systems and future challenges

Fostered by and embedded in the general development of information and communications technology (ICT), the evolution of tsunami warning systems (TWS) shows a significant development from seismic-centred to multi-sensor system architectures using additional sensors (e.g. tide gauges and buoys) for the detection of tsunami waves in the ocean. <br><br> Currently, the beginning implementation of regional tsunami warning infrastructures indicates a new phase in the development of TWS. A new generation of TWS should not only be able to realise multi-sensor monitoring for tsunami detection. Moreover, these systems have to be capable to form a collaborative communication infrastructure of distributed tsunami warning systems in order to implement regional, ocean-wide monitoring and warning strategies. <br><br> In the context of the development of the German Indonesian Tsunami Early Warning System (GITEWS) and in the EU-funded FP6 project Distant Early Warning System (DEWS), a service platform for both sensor integration and warning dissemination has been newly developed and demonstrated. In particular, standards of the Open Geospatial Consortium (OGC) and the Organization for the Advancement of Structured Information Standards (OASIS) have been successfully incorporated. <br><br> In the FP7 project Collaborative, Complex and Critical Decision-Support in Evolving Crises (TRIDEC), new developments in ICT (e.g. complex event processing (CEP) and event-driven architecture (EDA)) are used to extend the existing platform to realise a component-based technology framework for building distributed tsunami warning systems

Four Phosphates at One Blow: Access to Pentaphosphorylated Magic Spot Nucleotides and Their Analysis by Capillary Electrophoresis

The complex phosphorylation pattern of natural and modified pentaphosphorylated magic spot nucleotides is generated in a highly efficient way. A cyclic pyrophosphoryl phosphoramidite (cPyPA) reagent is used to introduce four phosphates on nucleosides regioselectively in a one-flask key transformation. The obtained magic spot nucleotides are used to develop a capillary electrophoresis UV detection method, enabling nucleotide assignment in complex bacterial extracts

Elimination of GPI2 suppresses glycosylphosphatidylinositol GlcNAc transferase activity and alters GPI glycan modification in Trypanosoma brucei

Many eukaryotic cell-surface proteins are post-translationally modified by a glycosylphosphatidylinositol (GPI) moiety that anchors them to the cell membrane. The biosynthesis of GPI anchors is initiated in the endoplasmic reticulum by transfer of GlcNAc from UDP-GlcNAc to phosphatidylinositol. This reaction is catalyzed by GPI GlcNAc transferase, a multisubunit complex comprising the catalytic subunit Gpi3/PIG-A as well as at least five other subunits, including the hydrophobic protein Gpi2, which is essential for the activity of the complex in yeast and mammals, but the function of which is not known. To investigate the role of Gpi2, we exploited Trypanosoma brucei (Tb), an early diverging eukaryote and important model organism that initially provided the first insights into GPI structure and biosynthesis. We generated insect-stage (procyclic) trypanosomes that lack TbGPI2 and found that in TbGPI2-null parasites, (i) GPI GlcNAc transferase activity is reduced, but not lost, in contrast with yeast and human cells, (ii) the GPI GlcNAc transferase complex persists, but its architecture is affected, with loss of at least the TbGPI1 subunit, and (iii) the GPI anchors of procyclins, the major surface proteins, are underglycosylated when compared with their WT counterparts, indicating the importance of TbGPI2 for reactions that occur in the Golgi apparatus. Immunofluorescence microscopy localized TbGPI2 not only to the endoplasmic reticulum but also to the Golgi apparatus, suggesting that in addition to its expected function as a subunit of the GPI GlcNAc transferase complex, TbGPI2 may have an enigmatic noncanonical role in Golgi-localized GPI anchor modification in trypanosomes

Sized Types for low-level Quantum Metaprogramming

One of the most fundamental aspects of quantum circuit design is the concept of families of circuits parametrized by an instance size. As in classical programming, metaprogramming allows the programmer to write entire families of circuits simultaneously, an ability which is of particular importance in the context of quantum computing as algorithms frequently use arithmetic over non-standard word lengths. In this work, we introduce metaQASM, a typed extension of the openQASM language supporting the metaprogramming of circuit families. Our language and type system, built around a lightweight implementation of sized types, supports subtyping over register sizes and is moreover type-safe. In particular, we prove that our system is strongly normalizing, and as such any well-typed metaQASM program can be statically unrolled into a finite circuit.Comment: Presented at Reversible Computation 2019. Final authenticated publication is available online at https://doi.org/10.1007/978-3-030-21500-2_

Archaeological medicinal earths as antibacterial agents: the case of the Basel Lemnian sphragides.

This paper presents the scientific investigation of three Lemnian sphragides (terra sigillata), a famed medicinal clay (earth) of antiquity, dated to the 16th-17th century, and presently in the collection of the Museum for the History of Pharmacy of the University of Basel. The three specimens are examined here against the backdrop of samples of sedimentary clays from the purported locality of its extraction, at Kotsinas, NE Lemnos, Greece. The study demonstrates, for the first time, that the three Lemnian sphragides displayed antibacterial properties against gram positive pathogens (staphelococcus aureus); the modern clays displayed none. Subsequent analysis with DPLC-MS of one of the three sphragides and one sample of clay revealed the presence of organic constituents in the sphragis which were absent from a sample of the modern clay. A fungal secondary metabolite is proposed here as the molecule responsible but other factors may have a role to play. The ongoing investigation for the bioactivity od some medicinal clays might aid in the re-evaluation of Belon's statement included at the start of this paper, namely, that the Lemnian Earth worked only because people in the past wished it to work

Expression of chicken lamin B2 in Escherichia coli : characterization of its structure, assembly, and molecular interactions

Chicken lamin B2, a nuclear member of the intermediate-type filament (IF) protein family, was expressed as a full-length protein in Escherichia coli. After purification, its structure and assembly properties were explored by EM, using both glycerol spraying/low-angle rotary metal shadowing and negative staining for preparation, as well as by analytical ultracentrifugation. At its first level of structural organization, lamin B2 formed "myosin-like" 3.1S dimers consisting of a 52-nm-long tail flanked at one end by two globular heads. These myosin-like molecules are interpreted to represent two lamin polypeptides interacting via their 45-kD central rod domains to form a segmented, parallel and unstaggered 52-nm-long two-stranded alpha-helical coiled-coil, and their COOH-terminal end domains folding into globular heads. At the second level of organization, lamin B2 dimers associated longitudinally to form polar head-to-tail polymers. This longitudinal mode of association of laminin dimers is in striking contrast to the lateral mode of association observed previously for cytoplasmic IF dimers. At the third level of organization, these polar head-to-tail polymers further associated laterally, in an approximately half-staggered fashion, to form filamentous and eventually paracrystal-like structures revealing a pronounced 24.5-nm axial repeat. Finally, following up on recent studies implicating the mitotic cdc2 kinase in the control of lamin polymerization (Peter, M., J. Nakagawa, M. Dorée, J. C. Labbé, and E. A. Nigg. 1990. Cell. 61:591-602), we have examined the effect of phosphorylation by purified cdc2 kinase on the assembly properties and molecular interactions of the bacterially expressed lamin B2. Phosphorylation of chicken lamin B2 by cdc2 kinase interferes with the head-to-tail polymerization of the lamin dimers. This finding supports the notion that cdc2 kinase plays a major, direct role in triggering mitotic disassembly of the nuclear lamina