German researchers have achieved a quantum entanglement record of photons. According to the team, the approach used could potentially be exploited by quantum computers.
Record quantum entanglement
L’quantum entanglement implies that two particles become so inextricably linked that examining one makes it possible to deduce the state of the other. Even stranger, if one of them is changed, his partner will be changed instantly too, regardless of the distance between them. First described in the 1930s, this strange physical phenomenon was called ” scary action from a distance by Einstein.
While it may sound paradoxical, it has been proven experimentally for decades, and in particular used by quantum computerswhere entangled particles can be used as quantum bits (qubits) for data storage and processing.
While researchers usually use large groups of entangled particles, for this new study published in the journal Naturea team from the Max Planck Institute explored a more reliable, engaging method 14 photons, be the largest group of such particles ever entangled.
The approach involves a rubidium atom trapped in an optical cavity allowing electromagnetic waves to bounce in certain patterns. The atom is first hit by a laser at a predefined frequency, preparing it to exhibit a particular property. A second pulse is then sent, causing the emission of a photon entangled with the atom.
A promising process
This two-step process was repeated, rotating the atom between each photon emission, until a whole chain of these particles was produced, all intertwined. Much more efficient than existing techniques, it produced photons in over 43% of cases (almost one photon for two laser pulses).
Although the number of 14 photons may seem miniscule compared to the trillions of atoms entangled in the gas in previous experiments, such arrays cannot be exploited for communications or quantum computers.
Already having a wide range of practical applications, photons are also much simpler to produce. According to the team, the new approach could easily be expanded to achieve more. The next step will be to repeat a series of experiments this time involving at least two atoms as sources.