Realizable Hamiltonians for Universal Adiabatic Quantum Computers

It has been established that local lattice spin Hamiltonians can be used for universal adiabatic quantum computation. However, the 2-local model Hamiltonians used in these proofs are general and hence do not limit the types of interactions required between spins. To address this concern, the present paper provides two simple model Hamiltonians that are of practical interest to experimentalists working towards the realization of a universal adiabatic quantum computer. The model Hamiltonians presented are the simplest known QMA-complete 2-local Hamiltonians. The 2-local Ising model with 1-local transverse field which has been realized using an array of technologies, is perhaps the simplest quantum spin model but is unlikely to be universal for adiabatic quantum computation. We demonstrate that this model can be rendered universal and QMA-complete by adding a tunable 2-local transverse XX coupling. We also show the universality and QMA-completeness of spin models with only 1-local Z and X fields and 2-local ZX interactions.Comment: Paper revised and extended to improve clarity; to appear in Physical Review

Charged spin 1/2 particle in an arbitrary magnetic field in two spatial dimensions: a supersymmetric quantum mechanical system

It is shown that the 2 X 2 matrix Hamiltonian describing the dynamics of a charged spin 1/2 particle with g-factor 2 moving in an arbitrary, spatially dependent, magnetic field in two spatial dimensions can be written as the anticommuator of a nilpotent operator and its hermitian conjugate. Consequently, the Hamiltonians for the two different spin projections form partners of a supersymmetric quantum mechanical system. The resulting supersymmetry algebra can then be exploited to explicitly construct the exact zero energy ground state wavefunction for the system. Modulo this ground state, the remainder of the eigenstates and eigenvalues of the two partner Hamiltonians form positive energy degenerate pairs. We also construct the spatially asymptotic form of the magnetic field which produces a finite magnetic flux and associated zero energy normalizable ground state wavefunction.Comment: 10 pages, LaTe

Why P/OF should look for evidences of over-dense structures in solar flare hard X-ray sources

White-light and hard X-ray (HXR) observations of two white-light flares (WLFs) show that if the radiative losses in the optical continuum are powered by fast electrons directly heating the WLF source, then the column density constraints imposed by the finite range of the electrons requires that the WLF consist of an over-dense region in the chromosphere, with density exceeding 10 to the 14th power/cu cm. Thus, we recommend that P/OF search for evidences of over-dense structures in HXR images obtained simultaneously with optical observations of flares

Improving California brush ranges /

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Net energy analysis of solar and conventional domestic hot water systems in Melbourne, Australia

It is commonly assumed that solar hot water systems save energy and reduce greenhouse gas emissions. Very rarely has the life-cycle energy requirements of solar hot water systems been analysed, including their embodied energy. The extent to which solar hot water systems save energy compared to conventional systems in Melbourne, Australia, is shown through a comparative net energy analysis. The solar systems provided a net energy saving compared to the conventional systems after 0.5 to 2 years, for electricity and gas systems respectively.<br /

The Bravyi-Kitaev transformation for quantum computation of electronic structure

Quantum simulation is an important application of future quantum computers with applications in quantum chemistry, condensed matter, and beyond. Quantum simulation of fermionic systems presents a specific challenge. The Jordan-Wigner transformation allows for representation of a fermionic operator by O(n) qubit operations. Here we develop an alternative method of simulating fermions with qubits, first proposed by Bravyi and Kitaev [S. B. Bravyi, A.Yu. Kitaev, Annals of Physics 298, 210-226 (2002)], that reduces the simulation cost to O(log n) qubit operations for one fermionic operation. We apply this new Bravyi-Kitaev transformation to the task of simulating quantum chemical Hamiltonians, and give a detailed example for the simplest possible case of molecular hydrogen in a minimal basis. We show that the quantum circuit for simulating a single Trotter time-step of the Bravyi-Kitaev derived Hamiltonian for H2 requires fewer gate applications than the equivalent circuit derived from the Jordan-Wigner transformation. Since the scaling of the Bravyi-Kitaev method is asymptotically better than the Jordan-Wigner method, this result for molecular hydrogen in a minimal basis demonstrates the superior efficiency of the Bravyi-Kitaev method for all quantum computations of electronic structure

Integrated scalable cyto-technology for recombinant protein bioprocessing

Biological knowledge of infectious diseases and other diseases for which vaccines may provide therapeutic benefits, such as cancer, is growing at an accelerated pace. The implications of this knowledge are improved stratification of diseases, possibilities for personalized treatments, and explicit understanding of protective immune responses to be elicited by vaccines. With this knowledge, it is becoming increasingly feasible to engineer vaccines for specific responses rather than relying on empirical development. Despite this potential, the challenge of routine, low-cost manufacturing of vaccines creates a barrier to transforming health care in both high- and low-resource countries. Vaccines today do not benefit from well-defined, platform-like processes for manufacturing, and concepts such as continuous bioprocessing remain largely within the realm of biopharmaceutical products. The InSCyT platform is an advanced prototype manufacturing system that provides integrated and automated production and purification of multiple protein therapeutics. The system allows end-to-end manufacturing of 100\u27s to 10,000\u27s of doses of recombinant protein drugs in days. It uses a state-of-the-art approach to process design and implementation that takes advantage of a fast-growing, tractable microbial host (Pichia pastoris) and continuous processing for automated, hands-free purification through simple 2- or 3-stage chromatographic processes. The platform design is highly modular, allowing facile process development and process deployment for multiple products. This feature emerges from the predictable behavior of the fermentation and cell culture fluids, and rapid cloning of new molecules, that together facilitate fast development of entirely new processes in weeks. To date, this system has been used to reproducibly manufacture high-quality human growth hormone (hGH), granulocyte-colony stimulating factor (G-CSF), and interferon-α2b (IFN-α2b) in an integrated, automated manner. The speed of production using the InSCyT prototype allows volumetric productivities that compare favorably to those for mammalian-based production. This talk will outline the design and capabilities of the InSCyT system, demonstrate the quality of biologic drugs made to date on the system, and outline opportunities for advancing the platform to provide new capabilities in manufacturing recombinant proteins for use in vaccines. As part of a Gates Foundation-funded Grand Challenge called ULTRA, we have begun to assess the feasibility of manufacturing millions of doses of a trivalent recombinant rotavirus vaccine annually on a small-scale production system like InSCyT. Integrated bioprocessing enabled by systems such as these could offer potential advantages for routine production in local regions with minimal infrastructure, and for democratization of manufacturing capacity for new vaccine concepts and personalized treatments in cancer