title: Optical switching of nuclear spin-spin couplings in semiconductors.
abstract: Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear-spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings.
authors: National Institute for Materials Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan. goto.atsushi@nims.go.jp
authors: Atsushi
authors: A
authors: Goto
authors: Shinobu
authors: S
authors: Ohki
authors: Kenjiro
authors: K
authors: Hashi
authors: Tadashi
authors: T
authors: Shimizu
mesh_terms: D003205:Computing Methodologies; D008027:Light; D008962:Models, Theoretical; D012666:Semiconductors