Scientists Report New Advances in Quantum Teleportation, Overcoming a Major Barrier to Practical Quantum Communication
Chinese researchers say they have shown quantum teleportation under new conditions, a success that may have significant implications for the development of quantum communication technologies.
The breakthrough, reported by researchers at Shanxi University in China, includes a successful demonstration of simultaneous teleportation with multiple sideband qumodes — light-based carriers of quantum information that may provide a promising alternative to discrete qubitswhich is currently viewed as the “gold standard” of quantum computation.
Because it used to be a long-standing obstacle to the technical realization of quantum teleportationthe successful transport of several qumodes in a continuously variable system may signal a great leap in entanglement-based quantum communication capabilities in the coming years.
Quantum Teleportation in the 21st Century
Although it sounds like science fiction, in the world of quantum communication, teleportation is very real. Unlike its fictional counterpart, where large objects—and even entire human bodies—can travel instantaneously across sometimes vast distances, quantum teleportation involves the transfer of information, rather than matter, that is carried from one location to another by exploiting the phenomenon in physics known as involvement.
The combined use of entanglement with normal classical information has enabled researchers to achieve quantum teleportation before, usually involving only a sideband qumode in continuous variable experiments. Such conditions depend on field amplitude measurements and CHAPTER—known as quadrature—which has a continuous range of values, making it ideal for applications that require high-precision data collection.
This is important because it differs from the normal communication technologies we rely on every day, which send communications in parallel—think of a telephone, which collects audio from callers’ voices through a transmitter (or microphone) and delivers it to the receiver (or earpiece) of each handset.
In contrast, quantum teleportation transfers information on a turn-for-turn basis, and its reach across multiple channels—similar to everyday communication systems—remains challenging.
A Quantum Communication Breakthrough
Now, according to a team led by Shanxi University researcher Xiaolong Su, the successful transmission of information, with built-in controls, has been achieved, allowing them to demonstrate what they call “deterministic continuous variable quantum teleportation” using multiple sideband qumodes simultaneously.
Their method relies on carefully tuned phases of a pair of classical communication channels in a system with adjustable frequency settings. This, they say, allows the team to use the phase control capabilities to achieve teleportation with five sideband qumodes within the 24 MHz bandwidth.
By using this phase-tuning method, the team also says that they were able to choose how many qumodes are teleported in each demonstration, which enables an additional level of control over the setup, rather than being limited to a certain number of qumodes that are successfully teleported.
Passing the Non-Cloning Limit
In addition to the variable control they achieved, the team also reported achieving teleportation outputs with fidelity of around 70%.
Importantly, the Chinese research team said that all the instances they observed exceeded the limit of non-cloning, a threshold that sets an upper limit on the fidelity of copies, as outlined in the related concept known as the no-cloning theorem. This benchmark is often used as a boundary point for measuring bona fide quantum teleportation, as opposed to what can be reproduced using classical methods.
Basically, the success of the team shows the teleportation of many sideband quantum states in parallel-itself a famous first-but also that the amount of sideband qumodes that can be teleported all at once is adjustable, with a little help from the phase of a classical channel.
“The results show a new method for quantum teleportation in many quantum states simultaneously and make an important step in improving the teleporting ability of quantum teleportation,” the team wrote.
The recent study, “Controllable deterministic quantum teleportation of multiple sideband qumodes,” was published in Science Bulletin.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime science, defense, and technology reporter with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him to X @MicahHanksand on micahhanks.com.
