Quantum algorithms for hidden nonlinear structures

Attempts to find new quantum algorithms that outperform classical computation have focused primarily on the nonabelian hidden subgroup problem, which generalizes the central problem solved by Shor's factoring algorithm. We suggest an alternative generalization, namely to problems of finding hidden nonlinear structures over finite fields. We give examples of two such problems that can be solved efficiently by a quantum computer, but not by a classical computer. We also give some positive results on the quantum query complexity of finding hidden nonlinear structures.Comment: 13 page

Interfacial Properties of Siloxane Containing Semifluorinated Diblock Copolymer and Nanocomposite Under Confinement

Interfacial structure and response of complex diblock copolymer thin films and polymer nanocomposites were studied using neutron reflectometry (NR), atomic force microscopy (AFM), and surface tension measurement. The interfacial structure and composition of the polymer at interfaces differ from those of bulk properties that underline their numerous applications such as smart coating, lubricants, and microelectronics. Here, I present the study of semifluorinated diblock copolymer poly trifluoro propyl methyl siloxane (PTFPMS-b-PS or SiF-b-PS) thin films and the dispersion of polyhedral oligomeric silsesquioxanes (POSS) nanoparticle (NP) in symmetric polystyrene-b-poly dimethyl siloxane (PS-b-PDMS) diblock copolymer. Semifluorinated polymers are of a particular interest because of their unique thermal and chemical stability induced by the fluorinated segments. Further, incorporation of fluorine affects the interfacial energy and consequently overall interactions of the polymers with their environment. Temperature response was first probed followed by the impact of exposure to hydrophilic (water) and hydrophobic (decane and toluene) solvents. To resolve the impact of fluorine in the diblock SiF-b-PS, a small fluorinated segment was introduced in the flexible siloxane backbone. The volume fraction of fluorinated segment (ΦSiF) varied from 0.03 to 0.46. Temperature effects study showed that even small fraction of fluorinated segment altered interfacial behavior impacting surface energy as well as wetting behavior. Further, fluorinated segments enhanced the film stability. NR study showed that the incompatibility between fluorinated and protonated blocks drive layering structure where protonated diblocks are often fully mixed. In the layered structure, air interface was fluorine rich and substrate interface proton rich. The layered structure was maintained, even annealing at ~60°C higher than glass transition temperature (Tg) of block copolymer. The effect of quality of casting solvent and preparation pathway on surface properties was studied using AFM and contact angle measurement. Mix solvent of tetrahydrofuran and toluene, which is good for entire polymer and pure toluene, selective for PS block were used to dissolve the polymer and thin films were prepared using both spin cast and drop cast methods. The study found that even small segment of fluorine enhanced segregation and morphology formed depends on the solvent used and mode of preparation. Morphology developed during annealing found to depend on the structure formed at the pristine state. Exposure to water vapor resulted in water penetration throughout the film for the lowest SiF fraction whereas in the higher SiF fraction fluorinated and protonated segments rearranged allowing water to reside at the upper proton rich layers. In the presence of hydrophobic solvents, fluorinated and protonated blocks rearranged in a way solvents preferentially resided in proton rich layers. In both hydrophilic and hydrophobic solvents, layered structure was maintained even after extended exposure time. Effects of the relative size of POSS NPs with polymer layers and flexibility of the block in the distribution of NPs in PS-b-PDMS was also studied. It was found that the distribution of NPs depends on the size of the matrix used. In shorter diblock, NPs mostly distributed towards the interfaces whereas in longer segments NPs distributed isotropically. With annealing, NPs migrated toward PDMS rich layer and air interface due to the entropic influence

Principles for designing a digital library

This article covers some basic principles underlying the design, implementation and maintenance of any digital library. These principles apply not only to conversion projects in which analog objects are converted to digital form, but to digital libraries in which the objects have always been in digital form ("born digitally") and to "mixed" digital libraries in which the objects may be of both types. The key challenges in front of designing any Digital Library are building the Resources, Interoperability, Intellectual Property and Effective Access. These principles acts as a base while building a Digital library

Ferroelectric Phase Transitions in Ultra-thin Films of BaTiO3

We present molecular dynamics simulations of a realistic model of an ultrathin film of BaTiO$_3$ sandwiched between short-circuited electrodes to determine and understand effects of film thickness, epitaxial strain and the nature of electrodes on its ferroelectric phase transitions as a function of temperature. We determine a full epitaxial strain-temperature phase diagram in the presence of perfect electrodes. Even with the vanishing depolarization field, we find that ferroelectric phase transitions to states with in-plane and out-of-plane components of polarization exhibit dependence on thickness; it arises from the interactions of local dipoles with their electrostatic images in the presence of electrodes. Secondly, in the presence of relatively bad metal electrodes which only partly compensate the surface charges and depolarization field, a qualitatively different phase with stripe-like domains is stabilized at low temperature

A novel method to discover datacenter hardware instantly using software defined grid model

Hardware (Servers, Storage, Switches) in Research & Development (R&D) datacenters may be used for ongoing research, development, testing, build, qualification and certification, performance, regression testing, resolving customer issues, and the like. Engineers may move the hardware frequently without involving the IT department to meet project requirements and may shutdown the hardware whenever not in use. Currently, there are no solutions available to locate the hardware when it is powered off. It may be useful to detect datacenter hardware instantly, even if the hardware is shutdown, powered off, or exists in an isolated private network. Further, a reporting module capable of reporting hardware location, serial number, configuration details, and the like may also be useful

First-principles accurate total-energy surfaces for polar structural distortions of BaTiO3, PbTiO3, and SrTiO3: consequences to structural transition temperatures

Specific forms of the exchange correlation energy functionals in first-principles density functional theory-based calculations, such as the local density approximation (LDA) and generalized-gradient approximations (GGA), give rise to structural lattice parameters with typical errors of -2% and 2%. Due to a strong coupling between structure and polarization, the order parameter of ferroelectric transitions, they result in large errors in estimation of temperature dependent ferroelectric structural transition properties. Here, we employ a recently developed GGA functional of Wu and Cohen [Phys. Rev. B 73, 235116 (2006)] and determine total-energy surfaces for zone-center distortions of BaTiO3, PbTiO3, and SrTiO3, and compare them with the ones obtained with calculations based on standard LDA and GGA. Confirming that the Wu and Cohen functional allows better estimation of structural properties at 0 K, we determine a new set of parameters defining the effective Hamiltonian for ferroelectric transition in BaTiO3. Using the new set of parameters, we perform molecular-dynamics (MD) simulations under effective pressures p=0.0 GPa, p=-2.0 GPa, and p=-0.005T GPa. The simulations under p=-0.005T GPa, which is for simulating thermal expansion, show a clear improvement in the cubic to tetragonal transition temperature and c/a parameter of its ferroelectric tetragonal phase, while the description of transitions at lower temperatures to orthorhombic and rhombohedral phases is marginally improved. Our findings augur well for use of Wu-Cohen functional in studies of ferroelectrics at nano-scale, particularly in the form of epitaxial films where the properties depend crucially on the lattice mismatch.Comment: 10 pages, 7 figures, 3 tables, resubmitted to PR