August 20, 2019
A series of superconducting qubits reproduces two key options of topological insulators.
W. Cai et al., Phys. Rev. Lett. (2019)
Dependable quantum computation would require gadgets that may defend fragile quantum states from environmental disturbances. To that finish, some researchers have pinned their hopes on topological insulators, supplies that intrinsically defend their novel electrical habits within the face of exterior perturbations. Nevertheless, nobody has but engineered a topological insulator in an ensemble of qubits, the quantum equal of digital bits. Now, Luyan Solar of Tsinghua College in Beijing and collaborators have completed simply that by crafting a string of qubits during which topological safety might be switched on and off at will.
The group fabricated a series of qubits out of superconducting circuits. Within the system’s default state, a spin-excitation (magnon) generated in a single qubit would propagate forwards and backwards alongside the chain. By tuning native magnetic fluxes to regulate the relative coupling power between the qubits, nonetheless, the group engineered a topological magnon insulator that sustained the excitation and constrained it to a single qubit.
By observing the magnon dynamics over time, the group was in a position to characterize two hallmarks of any topological insulator: the winding quantity, which is a parameter in momentum house that doesn’t change if the system is deformed, and edge states, during which qubit excitations crowd collectively on the boundaries of the system. Every has been seen earlier than in different quibit methods however by no means concurrently. The group says that these outcomes present that superconducting qubit chains can’t solely be simply engineered to have topological safety however also can present a versatile platform for investigating quite a lot of topological behaviors.
This analysis is revealed in Bodily Evaluation Letters.
Christopher Crockett is a contract author based mostly in Arlington, Virginia.
Commentary of Topological Magnon Insulator States in a Superconducting Circuit
W. Cai, J. Han, Feng Mei, Y. Xu, Y. Ma, X. Li, H. Wang, Y. P. Track, Zheng-Yuan Xue, Zhang-qi Yin, Suotang Jia, and Luyan Solar
Phys. Rev. Lett. 123, 080501 (2019)
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