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

Physicists have proven the importance of the mesoscale for quantum phase transitions

Low-temperature phase transitions in ferromagnets are characterized by destruction of the domain structure. In an article in Nature physicists write that for a theoretical description of the dynamics of such transitions, it is necessary to take into account not only microscopic, but also mesoscale symmetry. This discovery indicates the possibility of the existence of non-classical… Continue reading Physicists have proven the importance of the mesoscale for quantum phase transitions

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

Physicists have created a continuous time crystal

German and Philippine physicists have reported the creation of the first crystal in continuous time. It is based on a Bose condensate pumped by uniformly amplifying laser light in a resonator. The scientists were convinced that their crystal not only spontaneously breaks symmetry with respect to time translations, but is also resistant to pump noise.… Continue reading Physicists have created a continuous time crystal

Physicists have turned a pair of time crystals into an artificial qubit

Physicists have turned a pair of time crystals into an artificial feedback qubit and studied its dynamics. The crystals themselves were magnon condensates formed in liquid helium-3, whose population and relative precession phase behaved in the same way as the parameters of a two-level system. Unlike a real qubit, the created system allows you to… Continue reading Physicists have turned a pair of time crystals into an artificial qubit

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