Quantum experiment proves that atoms can exist in two places at the same time

A new experiment with helium atoms entangled in linear momentum could help bridge quantum mechanics and general relativity. It’s really strange to think that a particle can be in two places at the same time, but… “that’s how the universe works”.

It can be said that the universe has a split personality. Or, more rigorously, that it is our physical models of the universe that are fragmented.

To large scale of stars and galaxiesit’s gravity that rules. Albert Einstein’s general relativity elegantly describes its movement.

But, when we reach the domain of subatomic particles, quantum mechanics comes into play, and the rules of reality unfold in a strange game of oddsexplains .

Physicists call this glaring contradiction the quantum gravity problem. For decades, scientists have searched for a single theoretical framework, often dubbed Theory of Everythingcapable of bridging the gap between the physics of the very massive and the physics of the microscopic.

Now, physicists at the Australian National University (ANU) have taken an important step towards force these two incompatible worlds to dialogue with each other.

In a new study, recently published in Nature Communications, researchers were able to successfully demonstrate quantum entanglement using the physical movement — more specifically, the linear momentum — of massive atoms.

“This result confirms predictions made more than a century ago, according to which matter can be in two places at the same time and can interfere with itself even though it is in these two places”, he says Sean Hodgmanda Research School of Physics da ANU.

Since these atoms have mass, are subject to gravity. This breakthrough gives scientists an entirely new set of tools to test how the strange rules of quantum mechanics interact with the gravitational fields that shape the universe.

The ability to intertwine subatomic particles so that changes in one of them instantly affect the other, even at a distance, has been demonstrated many times.

However, Previous experiments have resorted to massless photonsor the internal characteristics of atoms and electrons, such as spin. As these demonstrations did not involve physical movement or mass, they did not allow us to know how entanglement interacts with gravity.

O entanglement is the strangest facet of the quantum world. If two particles are entangled, changing the state of one instantly affects the other, regardless of the distance separating them.

This It’s not just abstract theory: Scientists have demonstrated quantum entanglement in action countless times.

The first experiments, in the late 1990s, showed that quantum states could be transmitted over short distances. Later investigations proved that this works at increasingly greater distances, including to and from low Earth orbit, such as .

But the photons are practically weightless. As they have no mass, they are not ideal for testing the effects of gravity. For this task, helium atoms are much better suited. They have mass and, therefore, must necessarily feel the effect of gravity.

“From an experimental point of view, It is extremely difficult to demonstrate this”, says the study’s lead author and PhD researcher Yogesh Sridhar. “Several people have tried in the past to show these effects, but they have always fallen short.”

Then, how the physical movement of two atoms is intertwined relatively heavy? Cooling them to extreme temperatures and causing them to collide.

The research team cooled clouds of helium atoms to a fraction of a degree above absolute zero. This extreme cooling created a state of matter called .

Scientists then pushed these ultracold atomic clouds toward each other. When the atoms collided, they dispersedbut not in the way one might imagine.

In the strange world of quantum physics, instead of ricocheting in defined directions like billiard balls, the atoms follow, in practice, several paths at the same time. They move simultaneously left and rightup and down.

Since linear momentum determines where an object is going, having multiple linear momentum then means that the atom is, in practicemoving around several physical routes simultaneously. As it falls, the particle literally finds itself in two places at once.

To prove that the atoms were indeed intertwined in their movement, the team let them fall. During the fall, the atoms passed through a device called Rarity-Tapster interferometer. This system measured their linear momentum when they impacted a detector plate placed below.

Os helium atoms are ideal for this drop test because they can be trapped in a high-energy excited state. “This means they have high internal energy and release electrons that we can measure, which allows us to measure atoms with full three-dimensional resolution,” Hodgman explained to .

“It’s really strange for us, thinking that this is how the universe works“, says Hodgman. “You can read this in a manual, but it’s really strange to think that a particle can be in two places at once.”

Unfortunately, this behavior only applies in the world of particles… because we all know the way it would give us Sometimes we can be in two places at the same time.