May 8, 2024

MIT Pioneers Quantum Light Source for Optical Quantum Computers and Teleportation Devices for Communication

By David L. Chandler, Massachusetts Institute of Innovation
June 25, 2023

Tiny imaging reveals the size harmony of the perovskite nanocrystals. Credit: Courtesy of the researchers
Most principles for quantum computing use ultracold atoms or the spins of private electrons to act as the quantum bits, or qubits, that form the basis of such devices. About 2 decades ago some scientists proposed the concept of utilizing light instead of physical things as the basic qubit units.
” With these qubit-like photons,” Kaplan explains, “with just family direct optics, you can develop a quantum computer system, offered you have appropriately prepared photons.”
The preparation of those photons is the essential thing. Each photon needs to exactly match the quantum characteristics of the one in the past, and so on. As soon as that best matching is attained, “the actually huge paradigm shift then is altering from the requirement for extremely elegant optics, extremely expensive equipment, to needing just simple devices. The thing that requires to be unique is the light itself.”
Bawendi explains, they take these single photons that are identical and identical from each other, and they communicate them with each other. That indistinguishability is crucial: If you have two photons, and “whatever is the same about them, and you cant say primary and second, you cant track them that way. Thats what enables them to communicate in certain methods that are nonclassical.”
Kaplan says that “if we desire the photon to have this really particular residential or commercial property, of being extremely well-defined in energy, polarization, spatial mode, time, all of the things that we can encode quantum mechanically, we require the source to be very well-defined quantum mechanically also.”
The source they ended up using is a kind of lead-halite perovskite nanoparticles. The quick radiative rates thus uniquely place lead-halide perovskite nanoparticles to emit quantum light.
To evaluate that the photons they generate truly do have this indistinguishable property, a standard test is to detect a specific kind of interference between two photons, known as Hong-Ou-Mandel interference. This phenomenon is main to a lot of quantum-based technologies, Kaplan says, and therefore demonstrating its presence “has actually been a trademark for verifying that a photon source can be utilized for these functions.”
Really couple of materials can emit light that fulfills this test, he says. “They quite much can be noted on one hand.” While their new source is not yet ideal, producing the HOM interference just about half the time, the other sources have substantial problems with attaining scalability. “The reason other sources are coherent is theyre made with the purest products, and theyre made individually one by one, atom by atom. So, theres really poor scalability and very poor reproducibility,” Kaplan states.
By contrast, the perovskite nanoparticles are made in a service and just transferred on a substrate material. “Were generally just spinning them onto a surface, in this case simply a regular glass surface area,” Kaplan states. “And were seeing them undergo this behavior that previously was seen only under the most rigid of preparation conditions.”
Even though these materials may not yet be best, “Theyre extremely scalable, we can make a lot of them. and theyre currently very unoptimized. We can integrate them into gadgets, and we can further enhance them,” Kaplan says.
At this phase, he says, this work is “an extremely intriguing basic discovery,” showing the abilities of these products. “The value of the work is that ideally, it can encourage people to check out how to further improve these in various device architectures.”
And, Bawendi includes, by integrating these emitters into reflective systems called optical cavities, as has actually already been done with the other sources, “we have complete self-confidence that integrating them into an optical cavity will bring their homes up to the level of the competitors.”
Reference: “Hong– Ou– Mandel interference in colloidal CsPbBr3 perovskite nanocrystals” by Alexander E. K. Kaplan, Chantalle J. Krajewska, Andrew H. Proppe, Weiwei Sun, Tara Sverko, David B. Berkinsky, Hendrik Utzat and Moungi G. Bawendi, 22 June 2023, Nature Photonics.DOI: 10.1038/ s41566-023-01225-w.
The research study group consisted of Chantalle Krajewska, Andrew Proppe, Weiwei Sun, Tara Sverko, David Berkinsky, and Hendrik Utzat. The work was supported by the U.S. Department of Energy and the Natural Sciences and Engineering Research Council of Canada.

A lot of ideas for quantum computing use ultracold atoms or the spins of individual electrons to act as the quantum bits, or qubits, that form the basis of such gadgets. The preparation of those photons is the crucial thing. Each photon has to precisely match the quantum attributes of the one before, and so on. Bawendi describes, they take these single photons that are identical and equivalent from each other, and they interact them with each other. That indistinguishability is vital: If you have 2 photons, and “whatever is the same about them, and you cant state number one and number two, you cant keep track of them that way.

MIT scientists have found that unique photovoltaic nanoparticles can release streams of similar photons, possibly leading the way for new quantum computing technologies and quantum teleportation gadgets.
The gadget gives off a stream of single photons and might offer a basis for optical quantum computers.
Using novel products that have been widely studied as prospective brand-new solar photovoltaics, scientists at MIT have revealed that nanoparticles of these products can release a stream of single, identical photons.
While the work is presently a fundamental discovery of these materials capabilities, it may ultimately pave the way to brand-new optically based quantum computers, in addition to possible quantum teleportation devices for communication, the scientists state. The outcomes were released on June 22 in the journal Nature Photonics, in a paper by graduate student Alexander Kaplan, teacher of chemistry Moungi Bawendi, and 6 others at MIT.