Internet, social networks, and digital technologies have completely changed how people build personal, professional, and business relations. The basis of this society is the exchange of information, which comes down to the simplest units – bits. The bit can be 0 or 1, and usually in electronic circuits this is displayed by two voltage levels. The ability to store and process bits became the foundation of all modern electronics, making possible such familiar tasks as sending letters, listening to music, or complex computing simulations. In this, RAM (RAM) plays a huge role, providing temporary storage and quick access to data.
In recent decades, physicists have stepped further and gave science a new type of unit of information – Cubit. Unlike a classic bit, which is always equal to only 0 or 1, the qubits can be in a state of superposition, that is, both 0 and 1 at the same time. This feature opens up new horizons in calculations, although practical applications are still at the stage of research. For future quantum computers and quantum Internet, quantum memory will also be required – devices that can store qubits and issue them on request. However, so far there is no single standard solution suitable for everyone.
Recently, researchers from ICFO under the guidance of Professor South de Ridmaten have reached an important breakthrough in this area. In the journal Physical Review X they presented a system of ten controlled quantum memory cells, in which you can store qubits in an arbitrary combination and extract them upon demand. This became the development of their earlier work, published in npj quantum information. Photon technologies: spatial, when the condition is determined by the way the photon falls into the memory cell, and the temporary, where the qubit is set by the moment of the photon arriving. In their installation, they were able to store qubits in several temporary intervals within each cell, which became a unique feature of the approach.
A crystal doped by the praseodymium, chilled to a temperature of only 3 kelvin, was used to implement the experiment. It managed to allocate 250 spatio-temporal “slots” for storing qubits – this is a world record for a solid-state device with the possibility of selective data extraction. This result is especially valuable because the synchronization of quantum networks requires precisely