GoKawiilResearchers at Chalmers University of Technology in Sweden have introduced a new theoretical design for quantum systems based on what they call "giant superatoms." This concept offers a fresh way to protect, control, and share quantum information, potentially bringing scientists closer to building large-scale quantum computers.
Quantum computers are expected to transform fields like drug discovery and encryption by solving problems that are far beyond the reach of conventional machines. However, progress has been limited by a major challenge known as decoherence. This occurs when quantum bits, or qubits, lose their information due to interactions with their surroundings. Even small amounts of electromagnetic noise can disrupt the fragile quantum states needed for computation.
"Quantum systems are extraordinarily powerful but also extremely fragile. The key to making them useful is learning how to control their interaction with the surrounding environment," says Lei Du, postdoctoral researcher in applied quantum technology at Chalmers.
Lei Du is the lead author of a study that outlines this new type of quantum system. The design is built around giant superatoms, which combine several important features. These systems reduce decoherence, remain stable, and consist of multiple interconnected "atoms" that function together as a single unit.
What Are Giant Superatoms
Giant superatoms bring together two previously separate ideas in quantum physics: giant atoms and superatoms. While each has been studied on its own, this is the first time they have been merged into a single system. These structures behave like atoms but are not found in nature. Instead, they are engineered by scientists (see fact box below).
Giant Atoms and Their "Quantum Echo"
The idea of giant atoms was first introduced by researchers at Chalmers over a decade ago and is now widely used in the field. A giant atom is typically designed as a qubit (which is the smallest unit of quantum information). Unlike ordinary atoms, it connects to light or sound waves at multiple, physically separated points. This allows it to interact with its environment in several places at once, helping it preserve quantum information.
"Waves that leave one connection point can travel through the environment and return to affect the atom at another point -- similar to hearing an echo of your own voice before you've finished speaking. This self-interaction leads to highly beneficial quantum effects, reduces decoherence and gives the system a form of memory of past interactions," explains Anton Frisk Kockum, Associate Professor of Applied Quantum Physics at Chalmers and co-author of the study.
Extending Entanglement Across Distances
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