Researchers at the IBS Center for Quantum Nanoscience (QNS) in Seoul, South Korea, have successfully demonstrated using a scanning tunneling microscope (STM) to perform quantum computation using electrons as qubits, a press release said.
Quantum computing is usually associated with terms such as atom traps or superconductors that aid in isolating quantum states or qubits that serve as a basic unit of information. In many ways, everything in nature is quantum and can be used to perform quantum computations as long as we can isolate its quantum states.
The researchers at QNS used this principle to work with electrons as qubits. The spin of electrons can be compared to classical computing bits, where the direction of the reel, either up or down, can be considered as 0 or 1. Before it is measured, the electron can be in intermediate states, also known as superpositions, in quantum computing parlance. This makes them naturally occurring qubits, which can be measured with advances made in microscopy.
How does an atomic quantum computer work?
The research team, which consisted of scientists from Spain and Japan, also began using a flat, thin insulator surface made of magnesium oxide. On this, they dispersed titanium atoms and then mapped their positions using an STM capable of visualizing at atomic resolutions.
The tip of the STM was then used to move the titanium atoms around, and three of them were arranged in a triangle. The STM tip also emits microwave signals, which control the spin of one of the electrons in the titanium atom utilizing an electron spin resonance (ESR-STM) technique. By tuning the microwave frequency, the research team successfully got the electron's spin to interact with spins in other titanium atoms.
The team thus achieved a simple two-qubit computation with the bonus that the operation was completed in nanoseconds, which is much faster than any other qubit researchers have been working with.
Potential to scale
The novelty of the approach is the development of a qubit platform assembling one atom at a time. Atomic quantum devices have been developed before but have only been able to work with one qubit at a time. The ability to control multiple qubits simultaneously paves the way for researchers to work with single–, two-, and three-qubit gates with this platform.
Another advantage of this approach is that it offers many spin species and a wide variety of two-dimensional geometries that can be assembled on the surface to perform different computations.
Quantum computing systems are already being scaled up to hundreds of qubits, and the novel approach might seem to lag in the number of qubits available.
The research team is aware of this but suggests that their approach could hit a limit of 100 qubits. To scale up further, the researchers suggest adding multiple such STM quantum computers to perform calculations more complex.
The research findings were published in the journal Science.
Originally published on Interesting Engineering : Original article