148,481 research outputs found

    Universal Programmable Quantum Circuit Schemes to Emulate an Operator

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    Unlike fixed designs, programmable circuit designs support an infinite number of operators. The functionality of a programmable circuit can be altered by simply changing the angle values of the rotation gates in the circuit. Here, we present a new quantum circuit design technique resulting in two general programmable circuit schemes. The circuit schemes can be used to simulate any given operator by setting the angle values in the circuit. This provides a fixed circuit design whose angles are determined from the elements of the given matrix-which can be non-unitary-in an efficient way. We also give both the classical and quantum complexity analysis for these circuits and show that the circuits require a few classical computations. They have almost the same quantum complexities as non-general circuits. Since the presented circuit designs are independent from the matrix decomposition techniques and the global optimization processes used to find quantum circuits for a given operator, high accuracy simulations can be done for the unitary propagators of molecular Hamiltonians on quantum computers. As an example, we show how to build the circuit design for the hydrogen molecule.Comment: combined with former arXiv:1207.174

    Carbons Into Bytes: Patented Chemical Compound Protection in the Virtual World

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    “Virtual” molecular compounds, created in molecular modeling software, are increasingly useful in the process of rational drug design. When a physical compound is patented, however, virtual use of the compound allows researchers to circumvent the protection granted to the patentee. To acquire protection from unauthorized use of compounds in their virtual form, patentees must directly claim the virtual compound. But Supreme Court decisions such as Bilski v. Kappos and Mayo Collaborative Services v. Prometheus Laboratories, Inc. call into question whether virtual compound claims are patentable subject matter under § 101. Using the guidance offered by the Supreme Court and Federal Circuit, this Issue Brief argues that virtual compound claims are not abstract ideas and therefore, consistent with patent policy, qualify as patentable subject matter

    Logic Circuits Based on Extended Molecular Spider Systems

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    Spatial locality brings the advantages of computation speed-up and sequence reuse to molecular computing. In particular, molecular walkers that undergo localized re- actions are of interest for implementing logic computations at the nanoscale. We use molecular spider walkers to implement logic circuits. We develop an extended multi- spider model with a dynamic environment wherein signal transmission is triggered via localized reactions, and use this model to implement three basic gates (AND, OR, and NOT) and a cascading mechanism. We develop an algorithm to automatically generate the layout of the circuit. We use a kinetic Monte Carlo algorithm to simulate circuit computations, and we analyze circuit complexity: our design scales linearly with formula size and has a logarithmic time complexity

    Nanometric constrictions in superconducting coplanar waveguide resonators

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    We report on the design, fabrication and characterization of superconducting coplanar waveguide resonators with nanoscopic constrictions. By reducing the size of the center line down to 50 nm, the radio frequency currents are concentrated and the magnetic field in its vicinity is increased. The device characteristics are only slightly modified by the constrictions, with changes in resonance frequency lower than 1% and internal quality factors of the same order of magnitude as the original ones. These devices could enable the achievement of higher couplings to small magnetic samples or even to single molecular spins and have applications in circuit quantum electrodynamics, quantum computing and electron paramagnetic resonance.Comment: 4 pages, 4 figure
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