Scientists have made significant strides in quantum computing by utilizing individual atoms positioned on a surface. Rather than competing directly with leading quantum computing approaches such as Google and IBM, this technique offers the potential to study quantum properties in various chemical elements and molecules. By isolating quantum states known as qubits and fine-tuning their control, researchers believe this new development could pave the way for future advancements in quantum computation.
The research team, led by Andreas Heinrich at the Institute for Basic Science in Seoul, focused on the spin of electrons as “original” qubits. In its natural state, electron spin can exist in multiple intermediate states called superpositions, similar to how a compass needle can point in different directions. By manipulating the microwave signals emitted from a scanning tunnelling microscope (STM) tip, the team successfully controlled the spin of a single electron in one of the titanium atoms. This interaction extended to the spins in the other two titanium atoms, resulting in a two-qubit quantum operation that could be rapidly read out.
In their initial experiments, the researchers scattered titanium atoms on a perfectly flat magnesium oxide surface and mapped their positions using the STM. Using the tip of the STM probe, they rearranged three titanium atoms into a triangular formation. Through strategically tuned microwave frequencies, the team effectively controlled the spin of a single electron and orchestrated its interaction with the other two atoms.
Andreas Heinrich believes that expanding this technique to potentially 100 qubits by manipulating spins in individual atoms and molecules would be relatively straightforward. However, he acknowledges that further scalability may present challenges, as leading qubit technologies are already scaling up to hundreds of qubits. While Heinrich views their work as primarily focused on basic science, he envisions the possibility of linking multiple STM quantum computers to form a larger, more powerful system in the future.
Frequently Asked Questions
What is a qubit?
A qubit is the quantum equivalent of a classical computer’s memory bit. It is a quantum state that can represent both ‘0’ and ‘1’ simultaneously due to the concept of superposition.
What is spin?
Spin is an intrinsic property of particles, such as electrons, that behaves similarly to a compass needle. It can be in different orientations or directions, and in the context of quantum computing, it serves as the basis for qubit manipulation and control.
How does a scanning tunnelling microscope work?
A scanning tunnelling microscope (STM) is a powerful tool that enables scientists to observe and manipulate matter at the atomic level. It utilizes a tiny, sharp probe that scans over a surface, detecting the flow of electrons between the probe and the surface to create an image with atomic resolution.
What is the significance of this research?
This research represents a promising advancement in the field of quantum computing. By using an atomic-resolution microscope to control individual atoms and their quantum properties, scientists can gain valuable insights into the behavior and potential applications of quantum systems.