The development of parafermions, which are collections of electrons that act like liquids in a unique state of matter, may have just given the area of quantum computing a boost in coherence and error prevention. When electrons sustain temperatures near to absolute zero, researchers from Singapore's Nanyang Technical University have exhibited experimental results that they anticipate may result in parafermions (-273 degrees Celsius). By proving that there are circumstances in which electrons can have powerful interactions—something that scientists had only speculated up until now—the discovery made a significant advance.
Electricity is the product of the coordinated motion of electrons. However, although appearing to move in this "ordered" manner, electrons are actually traveling randomly. Because they are negatively charged, electrons resist one another, moving separately and randomly (like a gas) as opposed to as a cohesive unit. They may arrive at their destination with a few "bumps" along the route, similar to drunk drivers. But when electrons act like a liquid, it's like replacing the reckless drivers with courteous ones who respect each other's space, speed, and direction to avoid disputes and travel more efficiently.
Obviously, such drivers are the focus of considerable theoretical discussion, but at least the existence of strong electron interactions has now been shown experimentally.
There are fewer particle interactions and energy transfers between electrons and the system when they are forced to behave in a "helical Tomonaga-Luttinger liquid," as the name suggests. Thus, the amount of ambient and systemic interference that frequently leads to mistakes and collapsed quantum states in quantum systems is reduced. Another crucial component is the electrons having been previously cooled to almost absolute zero. This allows some materials to reach the state of a superconductor, where electrons flow freely across their surface with no electrical resistance, further reducing the likelihood of environmental interference. Particles are forced to slow down to the point where they practically become immobile as a result of the system being chilled to absolute zero (in the experiment, down to 4.5 Kelvin or -269 degrees Celsius).
For quite some time, electrons (and their spin characteristic) have been exploited as quantum-programmable particles. Improvements in electron control that result in fewer disturbances, therefore, mean fewer mistakes and greater coherence, which results in a longer lifespan for the real qubits that may store or process information. In reality, superconducting qubits are already used in a few quantum systems, including IBM's Quantum One and Quantum Two.
In this instance, researchers employed an atom-thick graphene substrate to install tungsten ditelluride crystals, a nearly two-dimensional substance known as a "quantum spin Hall insulator," which insulates gravity on the inside while having electrons on the outside. The study team assembled the graphene/tungsten ditelluride substrate, cooled it to absolute zero, and then placed it under a scanning tunneling microscope that was only one nanometer away from its surface. This is smaller than a DNA strand and smaller than any transistor ever created (even when looking at the ones powering the latest best graphics cards).
The scientists found that the electrons in the graphene/tungsten substrate enhanced their repulsion when placed under the scanning tunneling microscope and cooled to absolute zero. The interaction between the repulsion fields of each electron caused their mutual attraction to be so intense that the electrons were compelled to travel as a group. The scientists measured a Luttinger value between 0.21 and 0.33. When this value approaches 1, particle interactions are at their lowest. This parameter measures the intensity of particle interactions.
The electrons are propelled into collective motion when the Luttinger value is less than 0.5, indicating strong interactions. According to Assistant Professor Weber, this is the domain in which parafermions are projected to occur. The Luttinger value can only vary between 0 and 1, therefore this is a genuinely exceptional range of fluctuation, he said. "In no helical Tomonaga-Luttinger liquid has control of the Luttinger parameter been observed previously at such low levels."
By utilizing the recently constructed Ultra-Low Vibration Laboratory at NTU Singapore, the team is now aiming to lower temperatures even further. Researchers will be able to conduct tests in the laboratory at 150 millikelvins (mK), which is even lower than absolute zero and should allow them to observe parafermion groups in person and observe increased electron repulsion.
It's interesting to note that it appears that the researchers' strategy is partly related to Microsoft's own race to build so-called topological qubits and their necessary (but yet absent in operation) Majorana modes.
