“…This implies that the system eventually reaches the ground state of the original Ising model representing the solution to the combinatorial optimization problem. There exists a large body of analytical, numerical, and experimental studies on quantum annealing, and active debates are going on to compare quantum annealing with the corresponding classical heuristic, simulated annealing, recent examples of which include Matsuda et al (2009), Young et al (2010), Hen and Young (2011), Farhi et al (2012), Boixo et al (2014), Katzgraber et al (2014Katzgraber et al ( , 2015, Rønnow et al (2014), Albash et al (2015), Heim et al (2015), Hen et al (2015), Isakov et al (2016), Martin-Mayor and Hen (2015), Steiger et al (2015), Venturelli et al (2015), Crosson and Harrow (2016), Denchev et al (2016), Kechedzhi and Smelyanskiy (2016), Mandrà et al (2016a,b), Marshall et al (2016), and Muthukrishnan et al (2016).…”