NTT Research and Development 2012 Review of Activities

Overview

A challenge facing the development of quantum computers, which are expected to possess computational capabilities far exceeding those of conventional computers, is the correction of errors caused by environmental disturbances and/or inaccurate logic gate operations. By exploiting ‘quasiparticles^*1’ that behave differently from fundamental particles in nature, a totally new architecture for quantum computation with exceedingly low error rate might be possible. Our highly sensitive nuclear magnetic resonance^*2 measurements have unraveled the electronic states in a semiconductor device expected to host such exotic quasiparticles.

Features

• Opens the possibility of a totally new architecture for quantum computing (topological quantum computing^*3) with exceedingly low error rate.
• Exploits quasiparticles that behave differently from fundamental particles in nature.
• Exotic electronic state realized by virtue of pristine-crystal growth technique.
• Direct and non-distructive probing of correlated electronic states using a highly sensitive nuclear magnetic resonance technique.

Application scenarios

• Quantum computing (cryptanalysis, database searching, and simulation).

• *1 Quasiparticle: Exchange of two fundamental particles such as electrons leaves the state indistinguishable from the original one.
      For quasiparticles—a group of many particles collectively behaving as if they were one, theory predicts those (non-Abelian
      quasiparticles) with exceedingly unusual properties; their exchange would transform the state into one distinct from the original.
• *2 Nuclear magnetic resonance: spectroscopic technique exploiting the resonant absorption of electromagnetic waves by nuclei
      placed in a strong magnetic field.
• *3 Topological quantum computing: a new method of quantum computing performed by rearranging quasiparticles. The result of
      the calculation depends solely on the order of the quasiparticle exchanges and does not depend on the details of the
      quasiparticles' trajectories. This unique property of topological quantum computing is believed to make the error rate
      exceedingly low.
  - Our findings were made through joint research with the Japan Science and Technology Agency.