



@article {2377,
	title = {Simulating large quantum circuits on a small quantum computer},
	journal = {Phys. Rev. Lett.},
	volume = {125},
	year = {2020},
	month = {12/8/2020},
	abstract = {<p>Limited quantum memory is one of the most important constraints for near-term quantum devices. Understanding whether a small quantum computer can simulate a larger quantum system, or execute an algorithm requiring more qubits than available, is both of theoretical and practical importance. In this Letter, we introduce cluster parameters K and d of a quantum circuit. The tensor network of such a circuit can be decomposed into clusters of size at most d with at most K qubits of inter-cluster quantum communication. Our main result is a simulation scheme of any (K,d)-clustered quantum circuit on a d-qubit machine in time roughly 2O(K). An important application of our result is the simulation of clustered quantum systems---such as large molecules---that can be partitioned into multiple significantly smaller clusters with weak interactions among them. Another potential application is quantum optimization: we demonstrate numerically that variational quantum eigensolvers can still perform well when restricted to clustered circuits, thus making it feasible to study large quantum systems on small quantum devices.</p>},
	doi = {https://doi.org/10.1103/PhysRevLett.125.150504},
	url = {https://arxiv.org/abs/1904.00102},
	author = {Tianyi Peng and Aram Harrow and Maris Ozols and Xiaodi Wu}
}
