The Quantum Highway: Controlling Electrons with Kink States
The development of quantum electronics is a complex yet intriguing field that holds the key to creating advanced sensors and lasers. Researchers at Penn State have made significant progress in this area by uncovering a new way to control the flow of electrons using kink states. These kink states, which are electrical conduction pathways at the edge of semiconducting materials, can be switched on and off to precisely regulate electron movement in quantum systems.
Lead researcher Jun Zhu, a professor of physics at Penn State, envisions a future where kink states serve as the backbone of a quantum interconnect network. By manipulating these kink states, researchers aim to transmit quantum information over long distances within a chip, a feat that cannot be achieved with traditional copper wires due to resistance issues.
Published in Science, the team’s work paves the way for further exploration of kink states in electron quantum optics devices and quantum computers. Unlike conventional switches that regulate current flow through a gate, the researchers’ switch alters the conduction path itself, providing a unique approach to controlling electron movement.
The researchers utilized Bernal bilayer graphene to create devices with kink states, leveraging the material’s unique electronic properties to achieve the quantum valley Hall effect. This effect allows electrons to occupy different “valley” states and move in opposing directions without colliding, a phenomenon essential for quantum information transmission.
Graduate student Ke Huang, the first author of the study, highlighted the importance of achieving a quantized resistance value through cleaner devices, which prevent electron backscattering. By incorporating a graphite/hexagonal boron nitride stack as a global gate, the team successfully controlled electron flow within the kink states.
The researchers observed that the quantization of kink states persisted at higher temperatures, offering potential applications beyond cryogenic conditions. This finding opens up possibilities for utilizing kink states in practical quantum electronics systems.
By developing a switch that can efficiently control the flow of electrons, the team adds to their collection of kink state-based quantum electronics tools. These devices, such as valves, waveguides, and beam splitters, demonstrate the versatility and potential scalability of kink state technology.
Looking ahead, the researchers aim to explore how electrons behave like coherent waves when traveling along kink state highways. Collaborators from Zhejiang University in China and the National Institute for Materials Science in Japan contributed to this groundbreaking research, which was supported by several funding agencies including the U.S. National Science Foundation and the Japan Society for the Promotion of Science.
With the quantum highway system taking shape, the future of quantum interconnect networks looks promising as researchers continue to push the boundaries of quantum electronics.