title: Uncertain behaviours of integrated circuits improve computational performance.
abstract: Improvements to the performance of conventional computers have mainly been achieved through semiconductor scaling; however, scaling is reaching its limitations. Natural phenomena, such as quantum superposition and stochastic resonance, have been introduced into new computing paradigms to improve performance beyond these limitations. Here, we explain that the uncertain behaviours of devices due to semiconductor scaling can improve the performance of computers. We prototyped an integrated circuit by performing a ground-state search of the Ising model. The bit errors of memory cell devices holding the current state of search occur probabilistically by inserting fluctuations into dynamic device characteristics, which will be actualised in the future to the chip. As a result, we observed more improvements in solution accuracy than that without fluctuations. Although the uncertain behaviours of devices had been intended to be eliminated in conventional devices, we demonstrate that uncertain behaviours has become the key to improving computational performance.
authors.affiliation: Center for Exploratory Research, Research &Development Group, Hitachi, Ltd., Kokubunji, Tokyo 185-8601, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Yoshimura
authors.affiliation: Center for Exploratory Research, Research &Development Group, Hitachi, Ltd., Kokubunji, Tokyo 185-8601, Japan.
authors.forename: Masanao
authors.initials: M
authors.lastname: Yamaoka
authors.affiliation: Center for Exploratory Research, Research &Development Group, Hitachi, Ltd., Kokubunji, Tokyo 185-8601, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Center for Exploratory Research, Research &Development Group, Hitachi, Ltd., Kokubunji, Tokyo 185-8601, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Okuyama
authors.affiliation: Center for Technology Innovation-Information and Telecommunications, Research &Development Group, Hitachi, Ltd., Yokohama, Kanagawa 244-0817, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Aoki
authors.affiliation: National Institute of Informatics, Chiyoda, Tokyo 101-8430, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kawarabayashi
authors.affiliation: Management Planning Office, Hitachi, Ltd., Chiyoda, Tokyo 100-8280, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mizuno