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Quantum Crafting: Atom-by-Atom Construction of a New Qubit Platform

Researchers developed a groundbreaking electron-spin qubit platform assembled atom-by-atom. This enables the simultaneous control of multiple qubits, a significant step from the previous capability of managing only a single qubit. The platform offers atomic-scale precision and distinguishes itself from other qubit platforms in terms of flexibility and configuration.

Scientists at the IBS Center for Quantum Nanoscience (QNS) at Ewha Womans University have accomplished a groundbreaking step forward in quantum information science. In partnership with teams from Japan, Spain, and the US, they created a novel electron-spin qubit platform, assembled atomAn atom is the smallest component of an element. It is made up of protons and neutrons within the nucleus, and electrons circling the nucleus.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>atom-by-atom on a surface. This breakthrough was published in the journal Science on October 6.

Multi-Qubit Control

Unlike previous atomic quantum devices on surfaces where only a single qubit could be controlled, the researchers at QNS successfully demonstrated the ability to control multiple qubits simultaneously, enabling the application of single-, two-, and three-qubit gates.

Qubits, the fundamental units of quantum information, are key to quantum applications such as quantum computingPerforming computation using quantum-mechanical phenomena such as superposition and entanglement.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>quantum computing, sensing, and communication. Soo-hyon Phark, one of the QNS principal investigators, highlights the significance of this project. “To date, scientists have only been able to create and control a single qubit on a surface, making this a major step forward towards multi-qubit systems,” he stated.

New Qubit Platform Created Atom by Atom

The STM tip (Fe) operates the sensor qubit and romote qubits which creates the new multiple qubit platform. Credit: Institute for Basic Science

Innovative Qubit Platform

Led by Yujeong Bae, Soo-hyon Phark, and director Andreas Heinrich, QNS developed this novel platform, which consists of individual magnetic atoms placed on a pristine surface of a thin insulator. These atoms can be precisely positioned using the tip of a scanning tunneling microscope (STM) and manipulated with the assistance of electron spin resonance (ESR-STM). This atomic-scale control has allowed researchers to manipulate quantum states coherently. They also established the possibility of controlling remote qubits, opening the path to scaling up to tens or hundreds of qubits in a defect-free environment.

Yujeong Bae pointed out, “It is truly amazing that we can now control the quantum states of multiple individual atoms on surfaces at the same time.” The atomic-scale precision of this platform allows for the remote manipulation of the atoms to perform qubit operations individually, without moving the tip of the STM.

Current Qubit Platforms

Current qubit platforms. Credit: Institute for Basic Science

Comparison with Other Platforms

This research marks a significant departure from other qubit platforms, such as photonic devices, ion and atom traps, and superconducting devices. One of the unique benefits of this surface-based electron-spin approach is the myriad of available spin speciesA species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>species and the vast variety of two-dimensional geometries that can be precisely assembled.

Future Prospects

Looking forward, the researchers anticipate quantum sensing, computation, and simulation protocols using these precisely assembled atomic architectures. Altogether, the work by the QNS researchers is expected to usher in a new era of atomic-scale control in quantum information science, cementing Korea’s position as a global leader in the field.

Reference: “An atomic-scale multi-qubit platform” by Yu Wang, Yi Chen, Hong T. Bui, Christoph Wolf, Masahiro Haze, Cristina Mier, Jinkyung Kim, Deung-Jang Choi, Christopher P. Lutz, Yujeong Bae, Soo-hyon Phark and Andreas J. Heinrich, 5 October 2023, Science.
DOI: 10.1126/science.ade5050

Source: SciTechDaily