



@article {2607,
	title = {Implementing a Fast Unbounded Quantum Fanout Gate Using Power-Law Interactions},
	journal = {Phys. Rev. Research},
	volume = {4},
	year = {2022},
	month = {10/27/2022},
	abstract = {<p>The standard circuit model for quantum computation presumes the ability to directly perform gates between arbitrary pairs of qubits, which is unlikely to be practical for large-scale experiments. Power-law interactions with strength decaying as 1/rα in the distance r provide an experimentally realizable resource for information processing, whilst still retaining long-range connectivity. We leverage the power of these interactions to implement a fast quantum fanout gate with an arbitrary number of targets. Our implementation allows the quantum Fourier transform (QFT) and Shor\&$\#$39;s algorithm to be performed on a D-dimensional lattice in time logarithmic in the number of qubits for interactions with α\&le;D. As a corollary, we show that power-law systems with α\&le;D are difficult to simulate classically even for short times, under a standard assumption that factoring is classically intractable. Complementarily, we develop a new technique to give a general lower bound, linear in the size of the system, on the time required to implement the QFT and the fanout gate in systems that are constrained by a linear light cone. This allows us to prove an asymptotically tighter lower bound for long-range systems than is possible with previously available techniques.\&nbsp;</p>},
	doi = {https://doi.org/10.1103/PhysRevResearch.4.L042016},
	url = {https://arxiv.org/abs/2007.00662},
	author = {Andrew Y. Guo and Abhinav Deshpande and Su-Kuan Chu and Zachary Eldredge and Przemyslaw Bienias and Dhruv Devulapalli and Yuan Su and Andrew M. Childs and Alexey V. Gorshkov}
}
