NEC researchers control a superconducting qubit for the first time

Why it matters

Superconducting qubits grew out of this device and are now the basic unit of information in many quantum computers.

Sources (3)

• Nature Coherent control of macroscopic quantum states in a single-Cooper-pair box
  Primary sourceApr 29, 1999

  “Here we report the observation of quantum oscillations in a single-Cooper-pair box. By applying a short voltage pulse via a gate electrode, we can control the coherent quantum state evolution: the pulse modifies the energies of the two charge states non-adiabatically, bringing them into resonance. The resulting state—a superposition of the two charge states—is detected by a tunnelling current through a probe junction. Our results demonstrate electrical coherent control of a qubit in a solid-state electronic device.”

• The Quantum Insider NEC Halts Development of Quantum Computer Hardware
  Independent coverageSep 6, 2026

  “In 1999, NEC researchers became the first to demonstrate the operation of a superconducting solid-state qubit, the basic unit of information used in many quantum computers.”

• The University of Tokyo The joy of controlling quantum phenomena with the world's first quantum-bit element (UTOKYO VOICES 066)
  Independent coverageJun 20, 2019

  “Gracing the cover of the April 29, 1999 issue of Nature was an illustration of Professor Nakamura’s invention: the world’s first superconducting quantum bits (qubits) in a solid-state device.”