IBM has made a breakthrough in quantum computing by demonstrating a way to control the quantum behavior of individual atoms. The discovery has demonstrated a new building block for quantum computation. The team demonstrated the use of single atoms as qubits for quantum information processing.
A quantum bit or qubits are the fundamental blocks of a quantum computer’s ability to process information. IBM’s breakthrough marks the first time a single-atom qubit has been achieved using a Scanning Tunneling Microscope (STM). The STM can image and position each atomic qubit to precisely control the arrangement of the nearby qubit atoms.
The STM works by scanning the ultra-sharp needle tip near a surface to sense the arrangement of individual atoms, and the needle tip can pull or carry atoms into the desired arrangements. The basic unit of information in the computer is a bit with a value of “0” or “1”.
A Qubit can be a “0” or “1” simultaneously called superposition states. The state is a fundamental characteristic of quantum mechanics. IBM used a quantum property of a titanium atom called “spin” to represent one qubit. The spin property makes each titanium atom magnetic, so it behaves like a tiny compass needle.
Each titanium atom has a north and south magnetic pole, and the two magnetic orientations define the “0” or “1” of the qubit. IBM placed the titanium atom on a chosen surface of ultra-thin magnesium oxide to protect its magnetism and show off the quantum personality. The scientists then applied high-frequency radio waves, microwaves, to the atom. The microwaves come from the tip of the microscope and allow the team to steer the atom’s direction.
When tuned to the correct frequency, the titanium atom performs a “quantum dance” where its magnetic north pole spins around and ends in the desired direction. The dance, or Rabi oscillation, is extremely fast needing on 20 nanoseconds to turn the qubit around and back again. The atom ends on either a binary “0” or “1” depending on how long the radio waves are applied.