245 research outputs found

    Arithmetic on a Distributed-Memory Quantum Multicomputer

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    We evaluate the performance of quantum arithmetic algorithms run on a distributed quantum computer (a quantum multicomputer). We vary the node capacity and I/O capabilities, and the network topology. The tradeoff of choosing between gates executed remotely, through ``teleported gates'' on entangled pairs of qubits (telegate), versus exchanging the relevant qubits via quantum teleportation, then executing the algorithm using local gates (teledata), is examined. We show that the teledata approach performs better, and that carry-ripple adders perform well when the teleportation block is decomposed so that the key quantum operations can be parallelized. A node size of only a few logical qubits performs adequately provided that the nodes have two transceiver qubits. A linear network topology performs acceptably for a broad range of system sizes and performance parameters. We therefore recommend pursuing small, high-I/O bandwidth nodes and a simple network. Such a machine will run Shor's algorithm for factoring large numbers efficiently.Comment: 24 pages, 10 figures, ACM transactions format. Extended version of Int. Symp. on Comp. Architecture (ISCA) paper; v2, correct one circuit error, numerous small changes for clarity, add reference

    Fast Quantum Modular Exponentiation

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    We present a detailed analysis of the impact on modular exponentiation of architectural features and possible concurrent gate execution. Various arithmetic algorithms are evaluated for execution time, potential concurrency, and space tradeoffs. We find that, to exponentiate an n-bit number, for storage space 100n (twenty times the minimum 5n), we can execute modular exponentiation two hundred to seven hundred times faster than optimized versions of the basic algorithms, depending on architecture, for n=128. Addition on a neighbor-only architecture is limited to O(n) time when non-neighbor architectures can reach O(log n), demonstrating that physical characteristics of a computing device have an important impact on both real-world running time and asymptotic behavior. Our results will help guide experimental implementations of quantum algorithms and devices.Comment: to appear in PRA 71(5); RevTeX, 12 pages, 12 figures; v2 revision is substantial, with new algorithmic variants, much shorter and clearer text, and revised equation formattin

    Anti-gout potential of selected Malaysian local fruits

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    This study aimed to investigate the in vitro xanthine oxidase (XO) inhibitory activity and phytochemical content of guava, water rose apple, Malay gooseberry, pineapple and ambarella. The xanthine oxidase inhibitory activity was measured spectrophotometrically at 295 nm. The phytochemical analysis tested were total phenolic, total flavonoid and total anthocyanin contents of each methanolic extract of the fruits. The highest amount of phenolic was found in ambarella (0.245 mg GAE/g) while guava had the highest amount of flavonoid (0.472 mg RE/g). Meanwhile, water rose apple had the highest anthocyanin content (5.001 mg c-3-gE/g). For the XO inhibitory activity, water rose apple displayed the lowest IC50 value (26.86 μg/mL), showing better anti-gout activity as compared to that of other fruit samples. Positive correlation between total phenolic content and XO inhibitory activity was also observed in this study. Further study on the isolation of bioactive compounds from the fruit samples that act as XO inhibitor is greatly needed in the future

    A Synthesizable single-cycle multiply-accumulator

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    The multiplication and multiply-accumulate operations are expensive to implement in hardware for Digital Signal Processing, video, and graphics applications. A standard multiply-accumulator has three inputs and a single output that is equal to the product of two of its inputs added to the third input. For some applications it is desirable for a multiply-accumulator to have two outputs; one output that is the product of the first two inputs, and a second output that is the multiply-accumulate result. The goal of this thesis is to investigate algorithms and architectures used to design multipliers and multiply-accumulators, and to create a multiply-accumulator that computes both outputs in a single clock cycle. Often times in high speed designs the most time-consuming operations are pipelined to meet the system timing requirements. If the multiply-accumulate computation can be reduced to a single-cycle operation the overall processor performance can be improved for many applications. A multiply-accumulator with two outputs can be created using a combination of standard multiply, add, or multiply-accumulate components. Using these components, a multiplier and a multiply-accumulator can be used to produce the outputs in the most time-efficient manner. A multiplier and an adder will result in a smaller design with a larger worst-case delay. Therefore, the goal is to create a multiply-accumulator that is comparable in speed, but requires less area than a design using an industry standard multiplier and multiply-accumulator
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