# Niobium and Quantum computer chips (qubits)

Quantum computers being developed by IBM at its Q laboratory rely on superconducting qubits made from aluminum and niobium that sit atop a silicon substrate (the two superconducting electrodes sit between an insulator – or Josephson junction – of aluminum oxide).

Contrary to classical computers, which use binary digits (bits) that can have one of two states (0 or 1) at a time to solve mathematical and logical operations, a quantum computer uses quantum bits which can have two states simultaneously. It follows that two qubits can hold four values at once (00, 01, 10, and 11), three qubits can hold eight values and so forth, thereby creating a system that’s exponentially more powerful than a classic computer.

IBM’s machines must be kept in total darkness in temperatures of 50 millikelvin (-272.78 oC) to operate. IBM’s most advanced research quantum computer operates a 50 qubit system, although a 20 qubit model can be rented for research purposes. In both the 50- and the 20-qubit systems, the quantum state is preserved for just 90 microseconds. Further information is available here.