Quantum computing has shown a lot of promise as far as processing and transmission speeds are concerned, but it also suffers from limitations that limit the data that can be packed into a single photon. However, a new research intends to change that as scientists have managed to demonstrate a new way to pack more data on a single photon.
A team of researchers led by UCLA electrical engineers have demonstrated how they can slice up and entangle each photon pair into multiple dimensions using quantum properties such as the photons’ energy and spin. This method, called hyperentanglement, allows each photon pair to carry much more data than was possible with previous methods.
Previously, photons have typically been entangled by one dimension of their quantum properties — usually the direction of their polarization. This means that a photon was able to carry just a single qbit (quantum bit) of information.
Quantum entanglement could allow users to send data through a network and know immediately whether that data had made it to its destination without being intercepted or altered. With hyperentanglement, users could send much denser packets of information using the same networks.
For the research, scientists sent hyperentangled photons in a shape known as a biphoton frequency comb, essentially breaking up entangled photons into smaller parts.
In secure data transfer, photons sent over fiber optic networks can be encrypted through entanglement. With each dimension of entanglement, the amount of information carried on a photon pair is doubled, so a photon pair entangled by five dimensions can carry 32 times as much data as a pair entangled by only one. The result greatly extends from wavelength multiplexing, the method for carrying many videos over a single optical fiber.
“We show that an optical frequency comb can be generated at single photon level,” said Zhenda Xie, a research scientist in the lab of Chee Wei Wong, a UCLA associate professor of electrical engineering who was the research project’s principal investigator. “Essentially, we’re leveraging wavelength division multiplexing concepts at the quantum level.”
Potential applications for the research include secure communication and information processing, in particular for high-capacity data transfer with minimal error. This could be useful for medical servers, government data communications, financial markets and military communication channels, as well as quantum cloud communications and distributed quantum computing.
“We are fortunate to verify a decades-old theoretical prediction by Professor Jeff Shapiro of MIT, that quantum entanglement can be observed in a comb-like state,” Wong said. “With the help of state-of-the-art high-speed single photon detectors at NIST and support from Dr. Franco Wong, Dr. Xie was able to verify the high-dimensional and multi-degrees-of-freedom entanglement of photons. These observations demonstrate a new fundamentally secure approach for dense information processing and communications.”