A visual representation of a qubit, which can exist simultaneously between two states. A famous example of a qubit is Schrodinger's cat, a hypothetical cat that can be both dead and alive. Similarly, a flux qubit, or a ring made of a superconducting material, can have electric current flowing both clockwise and counterclockwise at the same time. Image: Yufan Li.Quantum computers with the ability to perform complex calculations, encrypt data more securely and predict the spread of viruses more quickly may be within closer reach thanks to a new discovery by researchers at The Johns Hopkins University.
"We've found that a certain superconducting material contains special properties that could be the building blocks for technology of the future," says Yufan Li, a postdoctoral fellow in the Department of Physics & Astronomy at The Johns Hopkins University and first author of a paper on this work in Science.
Today's computers use bits, represented by an electrical voltage or current pulse, to store information: bits exist in two states, either ‘0’ or ‘1’. Quantum computers, based on the laws of quantum mechanics, use quantum bits, or qubits, which do not just exist in two states, but a superposition of those two states.
The ability to use such qubits should make quantum computers much more powerful than existing computers when solving certain types of problems, such as those relating to artificial intelligence, drug development, cryptography, financial modeling and weather forecasting.
A famous example of a qubit is Schrodinger's cat, a hypothetical cat that may be simultaneously dead and alive. "A more realistic, tangible implementation of qubit can be a ring made of superconducting material, known as flux qubit, where two states with clockwise- and counterclockwise-flowing electric currents may exist simultaneously," says Chia-Ling Chien, professor of physics at The Johns Hopkins University and another author of the paper.
In order to exist between two states, qubits based on traditional superconductors require a very precise external magnetic field to be applied to each qubit, thus making them difficult to operate in a practical manner.
In this new study, Li and colleagues found that a ring of a polycrystalline material made from bismuth and palladium (β-Bi2Pd) already naturally exists between two states in the absence of an external magnetic field. Current can inherently circulate both clockwise and counterclockwise, simultaneously, through a ring of β-Bi2Pd.
"A ring of β-Bi2Pd already exists in the ideal state and doesn't require any additional modifications to work," says Li. "This could be a game changer."
The next step, he adds, is to look for Majorana fermions within β-Bi2Pd. Majorana fermions are particles that are also anti-particles of themselves and are needed for the next level of disruption-resistant quantum computers: topological quantum computers.
Majorana fermions depend on a special type of superconducting material – a so-called spin-triplet superconductor with two electrons in each pair aligning their spins in a parallel fashion – that has thus far proved elusive to scientists. Now, through a series of experiments, Li and colleagues have found that thin films of β-Bi2Pd possess the special properties necessary for the future of quantum computing.
Scientists have yet to discover the intrinsic spin-triplet superconductor needed to advance quantum computing, but Li is hopeful that the discovery of β-Bi2Pd's special properties will lead to them next finding Majorana fermions in the material.
"Ultimately, the goal is to find and then manipulate Majorana fermions, which is key to achieving fault-tolerant quantum computing for truly unleashing the power of quantum mechanics," says Li.
This story is adapted from material from The Johns Hopkins University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.