Redefining Quantum Communication: Researchers Have Solved a Foundational Problem in Transmitting Quantum Information

Advancement in Transmitting Quantum Information for High Speed Information Processing Illustration

Researchers from the Institute of Industrial Science, The University of Tokyo have solved a foundational problem in transmitting quantum information, which could dramatically enhance the utility of integrated circuits and quantum computing. Credit: Institute of Industrial Science, The University of Tokyo

Quantum electronics represents a significant departure from conventional electronics. In traditional systems, memory is stored in binary digits. In contrast, quantum electronics utilizes qubits for storage, which can assume various forms, including electrons trapped in nanostructures known as quantum dots. Nonetheless, the ability to transmit information beyond the adjacent quantum dot poses a substantial challenge, thereby limiting the design possibilities for qubits.

Now, in a study recently published in Physical Review Letters, researchers from the Institute of Industrial Science at the University of Tokyo are solving this problem: they developed a new technology for transmitting quantum information over perhaps tens to a hundred micrometers. This advance could improve the functionality of upcoming quantum electronics.

The Mechanism of Transmission

How can researchers transmit quantum information, from one quantum dot to another, on the same quantum computer chip? One way might be to convert electron (matter) information into light (electromagnetic wave) information: by generating light–matter hybrid states. Previous work has been incompatible with the one-electron needs of quantum information processing. Improving on high-speed quantum information transmission in a way that is more flexible in design and is compatible with the semiconductor fabrication tools that are currently available was the goal of the research team’s study.

“In our work, we couple a few electrons in the quantum dot to an electrical circuit known as a terahertz split-ring resonator,” explains Kazuyuki Kuroyama, lead author of the study. “The design is simple and suitable for large-scale integration.”

Previous work has been based on coupling the resonator with an ensemble of thousands to tens of thousands of electrons. In fact, the coupling strength is based on the large size of this ensemble. In contrast, the present system confines only a few electrons, which is suitable for quantum information processing. Nevertheless, both electrons and terahertz electromagnetic waves are confined to an ultra-small area. Therefore, the coupling strength is comparable in strength to that of many-electron systems.

“We’re excited because we use structures that are widespread in advanced nanotechnology – and are commonly integrated into semiconductor manufacturing – to help solve a practical quantum information transmission problem,” says Kazuhiko Hirakawa, senior author. “We also look forward to applying our findings to understanding the fundamental physics of light–electron coupled states.”

This work is an important step forward in solving a previously vexing problem in transmitting quantum information that has limited applications of laboratory findings. In addition, such light–matter interconversion is regarded as one of the essential architectures for large-scale quantum computers based on semiconductor quantum dots. Because the researchers’ results are based on materials and procedures that are common in semiconductor manufacturing, practical implementation should be straightforward.

Reference: “Coherent Interaction of a Few-Electron Quantum Dot with a Terahertz Optical Resonator” by Kazuyuki Kuroyama, Jinkwan Kwoen, Yasuhiko Arakawa and Kazuhiko Hirakawa, 9 February 2024, Physical Review Letters.
DOI: 10.1103/PhysRevLett.132.066901

4 Comments on "Redefining Quantum Communication: Researchers Have Solved a Foundational Problem in Transmitting Quantum Information"

  1. Bao-hua ZHANG | April 3, 2024 at 7:28 pm | Reply

    The Physical Review Letters (PRL) is the most evil, ugly, and dirty publication in the history of science. It is self righteous, self proclaimed, fooling the public, lack remorse, mystifying themselves, and don’t know what Shame is.

    Science and pseudoscience are not determined by a publication, an organization or a person, nor by you or me, but by mathematics the final say. Physical models must be based on mathematics or mathematical models in order to be scientific, convincing, and in accordance with natural laws.

    The origin of geometry lies in the concerns of everyday life. The branch of geometry (mathematics) known as topology has become a cornerstone of modern physics. Topological vortex and antivortex are two bidirectional coupled continuous chaotic systems. They exhibit parity conservation, charge conjugation, and time reversal symmetry. The synchronization effect is extremely important in their interactions. The synchronization effect of the superposition, deflection, and twisting of multiple or countless topological vortices will make spacetime motion more complex. To understand this complex world, physics should respect the authenticity of topological vortex in low dimensional spacetime, rather than simply relying on a few formulas, numbers, or imagined particles.

    Spin is a natural property of topological vortices. Spin is synchronized with energy, spin is synchronized with gravitation, spin is synchronized with time, spin is synchronized with evolution. The perpetually swirling topological vortices defy traditional physics’ expectations. One physical properties of topological vortices is them to spontaneously begin to change periodically in time, even though the system does not experience corresponding periodic interference. Therefore, in the interaction of topological vortices, time is both absolute and relative,and physics often requires treating space and time at the same level.

    Low-dimensional spacetime matter is the foundation of high-dimensional spacetime matter. Low-dimensional spacetime matter (such as topological vortex) can form new material structures and derive more complex physical properties via interactions and self-organization. It is extremely wrong and irresponsible to imagine low dimensional spacetime matter using high-dimensional spacetime matter,such as a cat in quantum mechanics.

    Science must follow mathematical rules. For example, the Standard Model (SM) is considered to be one of the most significant achievements of physics in the 20th century. However, the magnetic moment of μ particle is larger than expected, revealed by a g-2 experiment at Fermilab, suggests that the established theory (such as SM) of fundamental particles is incomplete. Furthermore, the SM omitting gravitation, it not involved the time problem and when the particle movement starts. Mathematics is the foundation of science. Physics must respect the scientific nature of mathematics and mathematical models. The SM must be based on mathematical models in order to be scientific, convincing, and in line with natural laws.

    I hope researchers are not fooled by the pseudoscientific theories of the Physical Review Letters (PRL), and hope more people dare to stand up and fight against rampant pseudoscience.
    The so-called academic journals (such as Physical Review Letters, Nature, Science, etc.) firmly believe that two high-dimensional spacetime objects (such as two sets of cobalt-60) rotating in opposite directions can be transformed into two objects that mirror each other, is a typical case of pseudoscience rampant.
    If researchers are really interested in Science and Physics, you can browse and

    The Physical Review Letters (PRL) is the most evil, ugly, and dirty publication in the history of science. Nature and Science have been influenced by Physical Review Letters (PRL) and are even more notorious. The behavior of these pseudo-academic publications has seriously hindered the progress and development of human society in science and technology.

    I am well aware that my relentless repetition can make some people unhappy, but in the fight against rampant pseudoscience, that’s all I can do.

  2. BibhutibhusanPatel | April 4, 2024 at 6:44 am | Reply

    Quantum mechanics relations of electrons with the light or electromagnetic waves is a basic fundamental science based on mathematical calculations used in the typical experiments;like one presented here.

    • Bao-hua ZHANG | April 4, 2024 at 7:58 am | Reply

      The universe does not do algebra, formula or fraction. The universe is geometrythe, and is the superposition, deflection, and twisting of geometric shapes.

      According to topological vortex gravitational field theory, vortices (matter) and antivortices (antimatter) are formed simultaneously, with the same geometric shape but opposite directions of rotation. Countless topological vortices make spacetime motion more complex via the synchronous effects of superposition, deflection, and twisting. Therefore, there is so much data coming in from the LHC, the most powerful accelerator in the world, that recording it all has never been an option.

      The rotation of topological vortices is spin. Spin creates everything, spin creates the world, spin creates the future. In the interaction of topological vortices, time is both absolute and relative,and physics often requires treating space and time at the same level. Spin occupies space, spin generates time, spin generates gravitation, spin generates energy, spin generates evolution. Each topological vortex is a quantum clock. Starting from the formation of topological vortices, precise timing begins.

      The interaction and balance of topological vortices not only demonstrate the beauty of mathematics, but also change the way humanity understand nature. Studying topological vortices can greatly expand the boundaries of humanity cognition.

      All observable movements in the physical world are inseparable from the interaction of topological vortices, including human observational behavior itself.

      • Bao-hua ZHANG | April 4, 2024 at 8:04 am | Reply

        To be precise, what God plays is two spinning coin. However, until you see the coin, you will not be able to determine whether you are seeing a Left-handed or right-handed spin coin.
        According to topological vortex gravitational field theory, at the moment of Creation, the geometric shapes of matter and antimatter are consistent. It is only the synchronous effect of countless “spinning coin” that makes spacetime motion more complex.
        Therefore, if there really is God, symmetry is God. Symmetry creates the world, symmetry creates all things. The world we see and observe is asymmetric because we can never see or observe the entirety of the world.
        The perpetually swirling topological vortices defy traditional physics’ expectations. Please believe in mathematics, geometry, and topology. If you are really interested in science, you can browse the comments of
        Wish you good luck.

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