15 Trillion Entangled Atoms

The process of quantum entanglement involves the loss of uniqueness of tiny particles like electrons or atoms so they can work together more efficiently.

Quantum technologies, such as gravitational wave detection, offer significant advancements in computing, communications, and sensing. Entanglement is at the core of these technologies.

Entanglement is notoriously delicate; typically, even a small disruption will cause it to break down. Since they must operate at temperatures very close to absolute zero, modern quantum technologies go to tremendous lengths to isolate the microscopic systems they work with. Contrarily, the ICFO researchers heated a group of atoms to XNUMX Kelvin, which is millions of times hotter than the majority of atoms utilized in quantum technology. The individual atoms weren't isolated however; every few microseconds, they hit with one another, sending their electrons whirling in all directions as a result.

The magnetization of this blazing, chaotic gas was observed by the researchers using a laser.

Magnetization results from rotating electrons in atoms and provides a way to study the effect of collisions and detect entanglement. What the researchers observed was a large number of entangled atoms, about 100 times more than previously observed.

In addition, they observed that entanglement is nonlocal and affects atoms far apart.

Between any two entangled atoms there are thousands of other atoms entangled, many with other atoms, in a giant, hot, scattered state.

"If we stop the measurement, the entanglement continues for about 1 millisecond, which means a new batch of 15 trillion atoms is entangled 1.000 times every second," says study author Jia Kong. They detected this in their observations.

You also have to believe that 1 ms is quite a long time for atoms, allowing about 50 random collisions to occur.

This clearly demonstrates that these random events do not break entanglement. This is perhaps the most unexpected result of the effort.

Detection of an ultra-sensitive magnetic field is possible by monitoring this hot and chaotic mixed state.

For example, a new line of sensors uses the same hot, high-density atomic gases to identify magnetic fields produced by brain activity in magnetoencephalography (magnetic brain imaging).

The latest findings suggest that entanglement may increase the sensitivity of this approach, which has uses in basic brain research and neurosurgery.

“This result is surprising, a real deviation from what everyone expected,” says ICREA Prof. of ICFO Morgan Mitchell.

Mitchell explains:

“This result is surprising, a real departure from what everyone expected without entanglement.” “We hope this type of giant entanglement will lead to better sensor performance in applications ranging from brain imaging to self-driving cars to dark matter searches.”

The system has no total angular momentum when the spins of several particles representing their intrinsic angular momentum add up to zero in a single spin.

In this research, the scientists used quantum non-destruction (QND) measurement to collect spin-related data from trillions of atoms. The process involves passing laser photons of a certain energy through an atomic gas.

Although atoms are not excited by the specific energy of these photons, they are still affected by the interaction. The polarization of the light is rotated by the spins of the atoms, which act as magnets. The amount of change in the polarization of the photons after traveling through the cloud allows the researchers to calculate the total spin of the atomic gas.

The operating range of modern magnetometers is known as SERF, which is very different from the temperatures used by scientists to study entangled atoms, which are often very close to absolute zero. Any atom in this regime often collides randomly with nearby atoms, and their collisions make the most significant impact on the atom's state.

Additionally, because they collide in a heated environment rather than an ultra-cold environment, the spin of the electrons in each atom is quickly randomized. Surprisingly, the experiment shows that such perturbation only transfers entanglement from one atom to another rather than disrupting the entangled states.

Source: ICFO-THE INSTITUTE OF PHOTONIC SCIENCES – heritagedaily

📩 28/06/2022 18:10