The ability to "flip" quantum information between various quantum technologies has important implications for the quantum network, communications and computing. The study was published in the journal Nature. It represents a new method for converting quantum data from a quantum computer format to the format required for quantum communication.
Quantum information systems need photons, which are particles of light, but different technologies use them at different frequencies. Superconducting qubits, for example, form the basis of some of the most popular quantum computing techniques and are used by tech giants like Google and IBM to store quantum information in photons moving in the microwave.
However, microwave photons cannot be used to interconnect quantum computers or build a quantum network because they cannot preserve quantum information throughout the journey.
Cell phones, Wi-Fi, GPS and similar devices all use microwave frequencies of light, according to Aishwarya Kumar, a postdoctoral researcher at the University of Chicago's James Franck Institute and lead author of the paper. But you cannot do this because the quantum information required for quantum communication is contained in a single photon. Also, this information will be masked by thermal noise at microwave frequencies.
The answer is to shift the quantum information to the optical photon, a higher frequency photon that is much more resistant to background noise. However, information cannot be transferred directly from one photon to another; intermediate is required instead. While some experiments create solid-state electronics for this purpose, Kumar's experiment focuses on something more fundamental: atoms.
Atomic electrons are only allowed to have a limited energy range or energy levels. A photon whose energy perfectly matches the difference between the lower and higher levels can excite an electron from a lower energy level to a higher level.
Similarly, when an electron is forced into a lower energy level, the atom releases a photon with an energy equal to the difference between the levels.
The two vacancies in the levels of the rubidium atoms used by Kumar's invention are those that exactly match the energies of an optical photon and a microwave photon. The method allows the atom to absorb a microwave photon with quantum information and then use lasers to change the atom's electron energy up and down to produce an optical photon with quantum information. “Transduction” refers to this transformation of quantum information between various states.
Significant advances in atom manipulation have allowed scientists to effectively use atoms for this purpose. Over the last 20-30 years, Kumar said, “we as a community have developed an extraordinary technology that allows us to control essentially everything about atoms.” Therefore, the experiment was well planned and efficient.
Kumar claims that advances in the field of cavity quantum electrodynamics, in which a photon is trapped in a superconducting, reflective chamber, are the second key to their success. The superconducting cavity forces the photon to bounce off in a closed environment, increasing the interaction between the photon and anything placed inside it.
Their rooms don't look very closed; actually it looks more like a swiss cheese block. But what looks like holes are actually tunnels that intersect in a very special geometry so that photons or atoms can be trapped at an intersection. This clever design also gives researchers access to the chamber to inject atoms and photons.
The technology is bidirectional and can carry quantum information from microwave photons to optical photons and vice versa. It could therefore be an important component of a quantum internet and lie on either side of a long-distance link between two superconducting qubit quantum computers.
But Kumar believes this technology could have much more uses than a quantum network. Its primary skill is the capacity to entanglement photons and atoms tightly, a crucial but challenging process in a wide variety of quantum technologies.
One of the things that “really excites us” is the platform's capacity to generate highly effective entanglement. "Entanglement; computation is at the heart of nearly all quantum applications we deal with, including simulations, metrology, and atomic clocks. I can't wait to see what else we can achieve.
Source: phys.org/news
Günceleme: 25/03/2023 14:45