Defects in quantum computers

Bibliographic description

title:	Defects in quantum computers
author:	Gardas Bartłomiej , Dziarmaga Jacek , Zurek Wojciech H., Zwolak Michael
Journal title:	Scientific Reports
volume:	8
date of publication:	2018
article ID:	4539
eISSN:	2045-2322
DOI:	10.1038/s41598-018-22763-2
language:	English
Journal language:	English
abstract in english:	The shift of interest from general purpose quantum computers to adiabatic quantum computing or quantum annealing calls for a broadly applicable and easy to implement test to assess how quantum or adiabatic is a specific hardware. Here we propose such a test based on an exactly solvable many body system–the quantum Ising chain in transverse field–and implement it on the D-Wave machine. An ideal adiabatic quench of the quantum Ising chain should lead to an ordered broken symmetry ground state with all spins aligned in the same direction. An actual quench can be imperfect due to decoherence, noise, flaws in the implemented Hamiltonian, or simply too fast to be adiabatic. Imperfections result in topological defects: Spins change orientation, kinks punctuating ordered sections of the chain. The number of such defects quantifies the extent by which the quantum computer misses the ground state, and is, therefore, imperfect.
affiliation:	Wydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut Fizyki im. Mariana Smoluchowskiego
type:	journal article
subtype:	academic paper