Quantum computers offer powerful improvements over standard machines, but to fully exploit their capabilities, a quantum network or quantum internet is needed. For years, scientists have been struggling with the practical difficulties of building such networks, which must transmit quantum information over long distances.
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Now scientists from the University of Chicago The Pritzker School of Molecular Engineering (PME) has proposed a new approach: building long quantum channels using vacuum tubes sealed with an array of spaced lenses. It would have a range of thousands of kilometers and a capacity of 10 trillion qubits per second, better than any existing quantum communication approach. Photons of the encoded quantum data would travel through the vacuum tubes and remain focused via the lenses, as detailed in the journal Physical Review Letters.
The quantum network is approaching, and there is an idea for how to build it
You probably know this already, but while classical computers encode data in traditional bits—represented by 0s or 1s—quantum computers rely on qubits, which feature two unusual quantum phenomena. They have to do with superposition—a kind of mysterious combination of states—and entanglement, which allows two quantum objects to interact over long distances.
Read also: These could be the next generation of quantum computers. Only this one thing was missing.
By linking many quantum computers together, we can achieve amazing computing capabilities. However, current networks are not good enough to do this because they cannot handle the quantum properties of qubits.
Scientists have tested ways to use optical fibers and satellites to transmit photons, which can act like qubits. Light particles can travel short distances through existing optical fibers, but they generally lose information quickly. Photons reflected by satellites and returning to Earth in the new location are absorbed less by the vacuum of space, but their transmission is limited by atmospheric absorption and the availability of satellites.
Scientists working on the Laser Interferometer Gravitational-Wave Observatory (LIGO) at the California Institute of Technology have built huge ground-based vacuum tubes to house the traveling photons that can detect gravitational waves. LIGO experiments have shown that photons can travel thousands of kilometers in a vacuum that is almost free of particles.
Professor Liang Jiang’s team began to wonder how smaller vacuum tubes could be used to transmit photons between quantum computers. In theory, it has been shown that properly designed tubes could transmit qubits across the country. Moreover, they would only need a medium vacuum (10.0 atmospheric pressure).-4 atmosphere), which is much easier to maintain than an ultra-high vacuum (10-11 atmospheres) required by LIGO.
The only problem is that as the photon moves through a vacuum, it scatters a little. To combat this, the scientists propose placing lenses every few kilometers to focus the beam. The scientists plan to test the practicality of this idea and then use larger vacuum tubes (like those in the LIGO observatory).
We believe that this type of network is possible and has great potential. It can be used not only for secure communications, but also for building distributed quantum networks, distributed quantum sensing technologies, and new types of telescopes and synchronized clocks.
Professor Liang Jiang
Echo Richards embodies a personality that is a delightful contradiction: a humble musicaholic who never brags about her expansive knowledge of both classic and contemporary tunes. Infuriatingly modest, one would never know from a mere conversation how deeply entrenched she is in the world of music. This passion seamlessly translates into her problem-solving skills, with Echo often drawing inspiration from melodies and rhythms. A voracious reader, she dives deep into literature, using stories to influence her own hardcore writing. Her spirited advocacy for alcohol isn’t about mere indulgence, but about celebrating life’s poignant moments.