Quantum computers are often touted as the next technological revolution because they will be able to solve complex problems much faster than traditional computers. However, a major challenge remains: these machines, sensitive to external disturbances, such as temperature variations or electromagnetic interference, suffer from what is called “decoherence”. This prevents them from working reliably. However, a team of researchers at the University of California, Riverside, recently made a discovery that could pave the way for more robust and reliable quantum computers: a new superconducting material capable of significantly reducing this phenomenon. This material could represent a key step in the development of more powerful quantum systems.
What is a superconductor and why is it essential for quantum computers?
And superconductor is a material that ceases to exhibit any electrical resistance when cooled below a certain temperature. This means that electrons can flow through the material without any opposition, a phenomenon that allows for almost lossless transfer of energy or information. This behavior is crucial in many applications, especially for systems that require perfect conductivity, such as high-power magnets or lossless power transmission lines.
In the context of quantum computers, information is processed by units called “qubits”. Unlike classic bits which can only be in a state of 0 or 1, qubits can exist in multiple states simultaneously thanks to the principles of superposition and thequantum interleaving. Superposition allows a qubit to be both 0 and 1 until it is measured, while interleaving allows separate qubits to stay connected and instantly influence each other's state , even from a distance.
Superconductors are used to manipulate these qubits because their ability to carry information without resistance is essential for creating stable quantum states. However, one of the main obstacles is that qubits are very sensitive to external interference, such as temperature variations or electromagnetic fields. This is where an improved superconducting material can come into play. Indeed, by reducing the decoherencethat is, the loss of quantum information, a better superconductor could make calculations more reliable and less prone to errors caused by the environment.
An innovative discovery: the superconductor with a two-dimensional interface
Researchers at the University of California, Riverside have developed an innovative superconducting material by combining a non-magnetic material called trigonal planet with an ultra-thin gold film. Trigonal tellurium is a material chiralmeaning its molecules lack mirror symmetry, a crucial property in quantum physics. In other words, the orientation of its molecules directly influences its quantum properties, which can be exploited in complex quantum systems like computers.
By combining this trigonal tellurium with gold, the researchers created an extremely clean two-dimensional interface between the two materials. This interface is particularly important, because it makes it possible to maintain a very well defined polarization. Polarization is an essential parameter in quantum physics, particularly for the manipulation of qubits. Thanks to this property, the material could potentially be used to control qubits with increased precision, making quantum calculations more stable.
Another notable feature of the material is its ability to become more robust when subjected to a magnetic field, suggesting that it could transform into a supraconducteur triplet. This type of superconductor is more resistant to magnetic fields than classical superconductors which can lose their quantum properties when exposed to too strong fields. By offering better resistance to external disturbances, this material could improve the stability and reliability of quantum systems, which is essential for the development of efficient quantum computers.
Next steps and challenges ahead
Although this discovery is promising, several challenges remain before this material can be integrated into large-scale quantum systems. One of the main issues is the temperature at which this material works effectively which is often close to absolute zero (0 K, or -273.15°C). Although the material shows high stability, it remains unclear whether it can be used at higher temperatures, which would pave the way for quantum computers that are easier to produce and operate.
Researchers will also need to continue testing the robustness of the material in varied conditions and figure out how to make it on a larger scale. However, the results obtained so far are encouraging and suggest a future where this type of superconductor could play a key role in the evolution of quantum computers.
