How could quantum memory be the answer to the quantum internet?
According to the article, recently published in the journal npj Quantum Information, the experiment consisted of storing and then retrieving two photonic qubits , two of the smallest units of information in a quantum computer, encoded in particles of light (photons).
- Find out more: The fantastic and bizarre world of quantum physics!.
The transmission and manipulation of quantum memory is the counterpart, at the subatomic level, of the traditional binary memory of our World Wide Web. While in this the data is encoded in binary states of 1 or 0, in quantum memory, it forms a quantum bit, which it can present a superposition of 1 and 0. But this ability to be in multiple states simultaneously disappears when the qubit is observed.
The importance of a quantum internet
The first advantage of quantum communication is its speed . In so-called “quantum entanglement”, two particles become so connected to each other that changes in one of them instantly affect the other, regardless of the distance between the two.
Furthermore, quantum communications are essentially more secure. This is because any hacking attempts would interfere with the quantum state of the particle , which would be easily observable by both the sender and the recipient of the message.
Although more viable than previous experiments in designing a future quantum internet, it is important to highlight that the team was only able to store photons for a fraction of a second, while qubits can last for more than an hour at cryogenic temperatures.
How important is the study in the transmission of quantum memories?
A quantum repeater jump requires two sources of entangled photon pairs, but separated by distance Source: Chase Wallace/Stony Brook University
Although there are quantum networks in operation around the world, such as one measuring two thousand kilometers between Beijing and Shanghai in China, they all need to be cooled to absolute zero in order to operate. In this sense, the Stony Brook team’s experiment stored two photons separately in rubidium gas and successfully recovered them in the quantum signature, and all at room temperature.
- Read also: The mysteries of the quantum universe and the discovery of photons by Albert Einstein.
According to co-author Daniel Oi, the most notable aspect here is that after taking two independently stored photons, retrieving and interfering them, “you get what is called a HOM dip, or a Hong-Ou-Mandel drop, as it is a characteristic quantum signature that indicates that these two photons were identical.”
The next step, the professor at the University of Strathclyde in Scotland tells Live Science, is to achieve “one of the holy grails of quantum memories” , which is to develop a method to identify the exact moment when a signal is ready to be recovered, without compromise its quantum properties through direct observation.
Stay up to date on technology and quantum physics, here at Top Technology World. If you wish, take the opportunity to learn more about what quantum entanglement is.
See too:
‘Metal scar on the surface of a white dwarf star’.
Using data collected by the Very Large Telescope (VLT) of the European Southern Observatory (ESO), in Chile, a group of researchers has identified a peculiar signature that presents a type of ‘metal scar on the surface of a white dwarf star’ . A study on the discovery was published in the scientific journal The Astrophysical Journal Letters.
This is the first time that scientists have managed to detect a signature of this type during space observations. To arrive at the result, the researchers used the Focal Reducer and Low Dispersion Spectrograph (FORS2) instrument on the VLT telescope.
The scar is formed by metals originating from a planetary fragment and is printed on the surface of the white dwarf named WD 0816-310 — the signal of these metals appears to change as the cosmic object rotates. In addition to the star being similar in size to Earth, its mass is closer to that of the Sun.
By observing that the signals of the metals seemed to change, the team realized that they were concentrated in a specific area of the star; hence, they called it ‘scar’. Probably, the metallic materials reached the surface due to the white dwarf’s magnetic field.
“We know that some white dwarfs – which slowly cool the embers of stars like the mighty Sun – are cannibalizing parts of their planetary systems. And now we discover that this star’s magnetic field plays a very fundamental role in this process, resulting in a scar on the star’s surface. the white dwarf,” said one of the lead authors and astronomer at Armagh Observatory and Planetarium, Stefano Bagnulo.