Quantum computing has enormous potential, but it faces a scalability problem. For such a machine to be useful in real terms, multiple quantum processors need to be assembled in a single location. This increases a processor’s power but also its size, making it less practical and more delicate. Scientists are working on a solution that sounds like something out of a science fiction series: connecting remote cores to each other through “quantum teleportation” to create even more powerful machines.
The path to such information transmission is beginning to appear. Recently, a team of scientists at the University of Oxford was able to send the first quantum algorithm wirelessly between two separate quantum processors. The two small cores took advantage of their unique nature, pooled their capabilities, and formed a superior computer to solve problems that neither of them could solve independently.
The team, led by graduate student Dougal Main, managed to get distant systems to interact with each other and share logic gates using quantum entanglement. Thanks to this quantum mechanical phenomenon, a pair of linked particles, even at a distance, can share the same state and therefore transmit the same information. If one changes state, the other instantly reflects it.
The Oxford scientists used quantum entanglement to almost instantaneously send basic information between computers. When data travels long distances under this principle, “quantum teleportation” is said to have occurred. This is not to be confused with the conventional idea of teleportation, which involves a hypothetical immediate exchange of matter in space. In the experiment, the light particles remained in the same place, but entanglement allowed the computers to “see” each other’s information and work in parallel.
According to the team’s research paper published in Nature, the quantum teleportation of an algorithm was possible with photons and with modules separated by two meters. The fidelity of the information had a rate of 86 percent. The result of this distributed quantum computing architecture is good enough to be a viable path to large-scale technology and the quantum internet.
Demonstrations of quantum teleportation in computational contexts have previously emerged, but have been limited to the transfer of states between systems. The Oxford University trial is distinctive because it used teleportation to create interactions between distant nuclei. “This breakthrough allows us to effectively ‘connect’ different quantum processors into a single, fully connected quantum computer,” Main recounted.
If distributed quantum computing technology continues to develop, the era of giant quantum machines may be behind us. The problem of scalability could potentially be solved with more machines operating together through quantum teleportation. For now, a basic processor can handle 50 qubits, a unit of quantum information. Some scientists estimate that a machine with the capacity to process thousands or millions of qubits will be needed to solve complex problems.
Even without entanglement, quantum machines are already powerful enough to solve seemingly impossible problems. Willow, Google’s quantum chip, recently solved a benchmark task called random circuit sampling in five minutes; it would have taken up to 10 quadrillion years for a conventional supercomputer to get the same result.
This story originally appeared on WIRED en Español, and has been translated from Spanish.