Accession Number : AD1010959

Title :   Computational Multiqubit Tunnelling in Programmable Quantum Annealers

Descriptive Note : Journal Article

Corporate Author : Google Venice United States

Personal Author(s) : Boxio,Sergio ; Smelyanskiy,Vadim N ; Shabani,Alireza ; Isakov,Sergei V ; Dykman,Mark ; Denchev,Vasil S ; Amin,Mohammad H ; Smirnov,Anatoly Y ; Mohseni,Masoud ; Neven,Hartmut

Full Text :

Report Date : 25 Aug 2016

Pagination or Media Count : 7

Abstract : Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunneling under high- and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive.

Descriptors :   annealing , QUANTUM BITS , ground state , probability , frequency , transitions , couplings , energy , fittings , optimization , freezing

Distribution Statement : APPROVED FOR PUBLIC RELEASE