Quantum Teleportation Just Got Even Faster
Yes, teleportation is real, and no, you can’t do it yet. But humankind has taken another step toward realizing a future in which teleportation affects our everyday lives, as researchers have recently demonstrated that teleporting information over a long distance is, indeed, possible.
The National Institute of Standards and Technology (NIST) announced in a statement that its research team, led by guest researcher Hiroki Takesue, successfully “transferred quantum information carried in light particles over 100 kilometers (km) of optical fiber, four times farther than the previous record”—which is to say, teleported this information from one end of the very long optical fiber to the other. The NIST, a non-regulatory U.S. Department of Commerce agency, explained:
The experiment confirmed that quantum communication is feasible over long distances in fiber. Other research groups have teleported quantum information over longer distances in free space, but the ability to do so over conventional fiber-optic lines offers more flexibility for network design.
The implied impact of the breakthrough may make waves in both the fields of quantum communications and quantum computing, "which offer prospects for novel capabilities such as unbreakable encryption and advanced code-breaking, respectively," the agency reports.
Described in an Optica article, the team's method relied on significantly improved instrumentation, now able to detect single photons (as well as each detected photon's arrival time, down to the nanosecond), and researchers were able to register the presence of individual photons. As the NIST's Marty Stevens pointed out, the team "never could have done this experiment without these new detectors, which can measure [the] incredibly weak signal" of a single photon, because only “about 1 percent of photons make it all the way through 100 km of fiber.”
As to how researchers used individual photons to communicate information (for lack of a better term) through 102 km of dispersion shifted fiber—four times as far as the previous teleportation record—without the photons actually covering that distance themselves, the study's methodology relied on the nature of "quantum states," a.k.a. the assessed qualities and predicted behavior of a bit of matter or energy (in this case, photons). Using their super-sensitive detectors, the team was able to detect the quantum states of photons at either end of the cable, and their detectors were hunting for photons with a very particular signature.
Specifically, the researchers generated a photon that was split by a special crystal into two identical photons. These photons are entangled which means they become a quantum system with each particle’s quantum state henceforth reflecting the other’s, no matter how far apart they are. And if you and I know, for example, that—thanks to this astounding but true physical principle—I can manipulate my quantum tin-can phone on one side of the neighborhood and that yours will mirror the reactions of mine from several backyards away, we effectively no longer need the string.
Feel like a visual aid would make a good digestif? Check out the NIST's helpful infographic below.