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Quantum Timing and Synchronization Problems

Diego de Falco·Dario Tamascelli
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Abstract

Feynman's model of a quantum computer provides an example of a continuous-time quantum walk. Its clocking mechanism is an excitation of a basically linear chain of spins with occasional controlled jumps which allow for motion on a planar graph. The spreading of the wave packet poses limitations on the probability of ever completing the $s$ elementary steps of a computation: an additional amount of storage space $δ$ is needed in order to achieve an assigned completion probability. In this note we study the END instruction, viewed as a measurement of the position of the clocking excitation: a $π$-pulse indefinitely freezes the contents of the input/output register, with a probability depending only on the ratio $δ/s$.

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Diego de Falco, Dario Tamascelli. 2005-04-05. Quantum Timing and Synchronization Problems. https://doi.org/10.1142/s0217979204024240

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