from h+ Magazine:
Unlike a conventional computer that works in a binary process of rapidly switching circuits on and off, a quantum computer uses subatomic phenomena to create logical circuits called qubits that are on and off at the same time.
Qubits can be a 1, a 0, or a quantum superposition of both. Put a pair of qubits together and they can be in a superposition of four states. With three qubits you can have eight states, and so on exponentially. D-Wave Systems intends to push the field further than ever before with the world’s first 128-qubit computer, running on superconducting circuits.