Nonlinearity of quantum dot waveguide helps entangle photons

European physicists have studied in detail the interaction of single photons in a photonic crystal waveguide containing a quantum dot. They showed that by varying the duration of the pulses and their delay, it is possible to achieve varying degrees of nonlinearity, as well as control the degree of correlation of light quanta. The study… Continue reading Nonlinearity of quantum dot waveguide helps entangle photons

Metasurfaces emit entangled photons with variable wavelengths

American and German physicists have fabricated thin metasurfaces consisting of arrays of silicon nanocavities that exhibit spontaneous parametric scattering. They showed that such structures are capable of generating entangled photons. Unlike traditional media used for this, metasurfaces have greater flexibility, which allows the wavelength of the resulting photons to be changed by changing the pump… Continue reading Metasurfaces emit entangled photons with variable wavelengths

One atom emits fourteen entangled photons

German physicists have reported the successful generation of entangled multiqubit states on photons using a single atom placed in a cavity. They managed to involve 12 photons in the creation of cluster states, and 14 photons of Greenberger-Horn-Zeilinger states. The frequency of generation and detection of entangled photonic chains based on the proposed scheme turned… Continue reading One atom emits fourteen entangled photons

The speed of interaction of Rydberg qubits has been brought closer to the fundamental limit

Japanese physicists have succeeded in achieving energy exchange between qubits based on Rydberg atoms on a nanosecond scale, approaching the fundamental limit of this platform. In the future, this will allow quantum computing to be performed faster than decoherence destroys the states of qubits. The study was published in Nature Photonic. Despite the wide variety… Continue reading The speed of interaction of Rydberg qubits has been brought closer to the fundamental limit

Physicists have experimentally confirmed quantum pseudotelepathy

Chinese physicists experimentally played the Mermin-Perez quantum game using hyperentangled photons. This game is an example of quantum pseudo-telepathy, that is, a game in which a quantum solution gives, in theory, a 100% guarantee of success. In practice, scientists won in 94 cases out of 100 due to noise and imperfections in the optical design,… Continue reading Physicists have experimentally confirmed quantum pseudotelepathy

White storks give up migrating to Africa to live in Spanish landfills

White storks have long stopped in Spain during their autumn migration to Africa. However, now many of them complete their journey here. Instead of continuing their flight, they spend the entire winter in Spanish landfills, feeding on garbage. In addition to the abundance of food, climate change contributes to this – winters on the Iberian… Continue reading White storks give up migrating to Africa to live in Spanish landfills

Theorists have solved quantum communication at interstellar distances

British theorists studied in detail the influence of the interstellar and circumstellar medium on the possibility of quantum communications at such long distances and came to the conclusion that such communication is possible. They showed that X-ray radiation is best suited for this, and the quantum signal itself can become a good marker of an… Continue reading Theorists have solved quantum communication at interstellar distances

Qubit helped entangle and measure mechanical resonators

American physicists reported that they were able to create a strong connection between a qubit and a pair of mechanical resonators. By controlling the properties of the qubit and communication parameters, they were able not only to entangle mechanical resonators, but also to conduct quantum tomography of their state. The study was published in Nature.… Continue reading Qubit helped entangle and measure mechanical resonators

Neutral atoms cope with solving optimization problems

Physicists have assembled a system of neutral atoms capable of generating entangled states and implementing quantum algorithms. Unlike its predecessors, the new computer turned out to be more stable and scalable thanks to the use of long-lived qubit atoms. The work was published in the journal Nature. The difficulty of scaling quantum computers lies not… Continue reading Neutral atoms cope with solving optimization problems

The coherence time of mechanical vibration exceeded one hundred milliseconds

Danish physicists reported the creation of an electromechanical device consisting of a membrane coupled to a microwave resonator, in which they were able to achieve a mechanical coherence time of 140 milliseconds. To do this, they cooled the membrane using the side-band method, achieving an average phonon number of 0.76. The study was published in… Continue reading The coherence time of mechanical vibration exceeded one hundred milliseconds