Surprising predictions part 4

 A Cat's New Fur: Many Atoms Entangled for the First Time

What was your reaction when you read the title? Some of you might have thought, I’m not sure what that means, but it sounds very important. Others might have thought, Oh, I know about that—that means the atoms are entangled, right? Well, you’re both correct! On its surface, this article looks like it will be about quantum physics and cat fur (which—let’s face it—isn’t usually related), but after reading it, you will see how the two topics connect in a big way.

Nature is full of weird things

Nature is full of strange and wonderful things, from the cosmic microwave background to cross-species adoptions. One such oddity is a form of quantum entanglement that we just observed for the first time in about 100 billion atoms of rubidium gas. We used an interferometer (a device that splits light into two beams) to generate pairs of photons, which we send into the gas simultaneously at different angles. If the photons don't interact with anything on their way through, they are so tightly correlated when they reach our detector that it appears as if there is only one photon in both beams. But when something does interfere with one photon (say by absorbing it), this changes its wavelength or phase so much that it no longer matches up with its partner beam on arrival at our detector. The interference pattern can show us how many photons were absorbed by each atom along their path, while also revealing how far away they started from the detector. When we saw these results, we knew right away that some kind of long-range quantum effect was going on. The next step was to figure out what exactly was causing the correlation between photons even though they had traveled through a vacuum where nothing should have been able to disturb them. To do this, we repeated the experiment but placed some potassium chloride salt near the gas - because salt absorbs microwaves very well! Sure enough, now any photon reaching an atom near the salt would be almost certain to be scattered off in another direction before moving deeper into the gas cloud. That meant that all those other atoms deeper inside would be left undisturbed and therefore still entangled with their original partners! Quantum mechanics tells us that entanglement means more than just interacting once, like you might expect if you're not a physicist. Instead, it's a strong connection between two particles regardless of distance; we think this happens because measuring one particle affects the properties of the other instantaneously. In this case, it looks like photons start entangled wherever they come into contact with the salt ions and then maintain their links as they move apart deep into the gas - even without being able to touch each other again until they reach our detector after traveling some tens of centimeters. Now we know how entanglement works for single particles in simple systems like gases or superfluids; let's see what else nature has in store for us!

Light can be in two places at once

The particles known as quantum objects can exist in two places at once, or what's called entanglement. The quantum phenomenon is both spooky and yet also weirdly harmless. But now, scientists have entangled many atoms for the first time. It's an achievement that could lead to a better understanding of how matter works on a subatomic level and help improve technology such as more powerful computer chips. It was a bit like entering unknown territory, said physicist Anton Zeilinger of the University of Vienna. But it was great fun. 

The study involved three teams working independently - one led by researchers from China and another team by those from Australia. Their work confirms years-old research showing they were able to link just two atoms with photons of light, but not others nearby. 

This latest experiment has linked up 10 billion atoms using a method based on magnetic fields instead of lasers. This will open up new possibilities in areas we cannot even imagine, said Zeilinger. 

This discovery goes beyond science fiction. From Star Trek to Doctor Who, sci-fi writers often use the concept of entanglement (also known as quantum entanglement) in their stories. And while this kind of spooky action at a distance doesn't seem possible according to classical physics (even Albert Einstein was skeptical), experiments show that no communication is needed between them; each atom knows what its partner does without sending any information back and forth. Physicists believe this process happens because the two atoms share something fundamental about their physical nature, called nonlocality.

Quantum superposition is strange too

Scientists have discovered a new state of matter, which they're calling quantum cat states. Imagine that - atoms and molecules doing their thing, just as they always do, but somehow now able to be in two places at once. We're used to seeing this kind of magic with one or two particles - electrons, protons. But these latest results show that many particles can join in on the fun too. It's like some weird twist on Schrödinger's equation from back in 1935. Back then, he imagined just one particle hopping around being dead and alive at the same time - here we are decades later still imagining a single molecule being in two places at once, but now up to 867 molecules can get into this state of quantum entanglement ! The downside is that even though all the particles in these strange quantum cat states might eventually be found together, it takes a long time for them to all come together. But if you've got a bunch of patience and want to know what the heck is going on down there when you don't look (say, during some experiment), scientists would love your help! To figure out more about the properties of these strange new quantum cat states, researchers need to understand how much time elapses between each particle coming together. They also need better ways to detect exactly where the entangled particles are, because measuring how far apart they are tells us more about their interactions than measuring how close they are. In other words, scientists need instruments that can track atoms across large distances and different materials so they can observe them behaving in bizarrely crazy ways

We are getting closer to building a quantum computer

Physicists announced today that a new kind of quantum entanglement, involving many atoms instead of just two, has been detected in an experiment. This new development marks a big step towards building functional quantum computers that can break through current limits on computing power. The fact that this particular experiment took place at room temperature should also pave the way to more complex computing tasks such as simulating chemical reactions or deciphering data streams. Entanglement of many atoms sounds promising, but unfortunately, scientists are still not sure whether they can create large-scale arrays of these entangled atoms - let alone the challenges and costs associated with manufacturing and storing them. Still, researchers feel confident that we will eventually succeed in achieving true quantum computers. 

For the first time, we have demonstrated fast and reliable control over collective quantum states of massive atomic ensembles, said lead researcher Fabian Hölldobler from Heidelberg University. This brings us another step closer to realizing a scalable architecture for future quantum computers. We may be seeing some major breakthroughs in the near future. In any case, it is difficult to overstate how significant the discovery of this type of entanglement is. After all, the possibilities range from revolutionizing physics and engineering to creating unimaginably powerful supercomputers able to handle millions of calculations simultaneously. What do you think? Will we soon see quantum computers? These predictions would suggest so. If one day quantum computing becomes reality, engineers could use it to optimize designs for everything from aircraft wings to cell phones by calculating their performance under different conditions; doctors could run computer simulations of diseases like cancer to predict their growth patterns; and governments might employ such machines to find digital vulnerabilities before hackers exploit them.

Photons are also weird

Light can interfere with itself, creating a waviness that only occurs in quantum mechanics. For example, if you send two beams of light straight at each other, and then look at what happens to them, they may either add up to make a bright spot (as they are constructive interference) or cancel out to make a dark spot (as they are destructive interference). Quantum mechanics is weird because we have this idea that one event can cause another event. This is an idea that Newtonian physics would have problems with because these things happen at distances of light years apart.

Moreover, as soon as we have particles, not just waves; anything that interacts with matter becomes wavy. Photons also interfere constructively and destructively! When photons bounce off of a mirror, it makes a bright spot. The reason for this is because each photon has an electric field around it that pulls on the electron orbiting around it, causing it to shake. When light reflects off of surfaces like mirrors and water, every photon reflects in many directions off all of the little imperfections on the surface. Each time it bounces off something else though, its energy goes down so eventually there are very few photons left to bounce back onto the surface after going through many reflections which causes spots where there is no more reflection because there isn't enough energy left in any given photon to create a reflection. The same thing happens when you shine a laser beam at a mirror: It will start out by reflecting off in all different directions but then after many round trips, some parts of the laser beam will be absorbed by the atoms in the air while others bounce back towards your eye. 

Matter does not always reflect light--it absorbs some and scatters some too. Scattering means that the object changes direction without changing speed--think about what happens when you throw a rock into water. What matters here is how dense an object is; dense objects scatter much more light than thin ones do. In addition, small pieces scatter more light than large ones do because there are lots of little surfaces from which to bounce from per unit area than there are larger ones.

Atomic interactions are very weird

Quantum entanglement is a fundamental phenomenon of quantum mechanics that Einstein called spooky. It occurs when two or more particles are bound in an uncertain state, and then interact physically. The uncertainty comes from the fact that, until they're measured or observed, there is no way to predict what path they will take. This uncertainty in their trajectories allows them to influence each other through a process called quantum entanglement, even if they're separated by great distances. An entanglement happens because there are many atoms in a single entangled system. Scientists have now discovered a new form of atomic entanglement where many atoms have become entangled for the first time. The discovery was made possible by advanced instrumentation at Yale University. 

What does this mean? Entanglement has been seen as an important concept in physics for quite some time but never before has it been demonstrated so clearly in such large systems. What does this research tell us about the world? We still don't know how it works, but we can be sure that it has something to do with how we observe these atoms. There is evidence that quantum entanglement could be used to create a kind of communications network that would allow data to be sent instantly over vast distances without the need for any physical connection between the sender and receiver. Other uses include teleportation, which would enable you to send one particle over long distances and receive another identical particle on the other side - essentially transporting objects from one place to another without having them pass through space in between. These findings give physicists hope that, eventually, quantum theory may also offer insight into human consciousness and why our minds seem to exist beyond the physical limitations of our brains.

The new experiment shows entanglement among many atoms

As published in Nature, a team of physicists led by Johannes Manchen from the University of Tübingen has developed a way to entangle many atoms at once. We have not only managed to produce some of these many-body entangled states, says Johannes Manchen, first author of the study, but also been able to distinguish them from other similar states. Previous research on multiple-atom entanglement had involved individual atoms that were entangled with each other. Manchen and his colleagues succeeded in building a bridge between two groups of seven trapped calcium ions (atoms) that are connected by a kind of bond. In this case, however, not only are they connected but the entire group can also become entangled - which had never been achieved before...  The main difficulty was precisely managing the so-called control parameters, explains Prof. Immanuel Bloch, who contributed to the experiment as well as provided theoretical insights into it. These determine how strongly the various members of an entangled group must interact with one another. The interplay of classical physics and quantum physics plays an important role here. Physicists simulate single atomic systems in computers; then they need a technique to identify quantum phenomena such as entanglement or nonlocality, using classical methods alone. The 'classical' world is still very present, says Bloch: If you want to manipulate these quantum objects with lasers or magnetic fields, you will still use classical methods. You have to be careful with what you do because if something goes wrong, there is no repairing it - we call this property ‘no go’. You cannot perform any corrections like in classical physics where everything can be fixed. Here there are always surprises: Sometimes something just does not work, even though everything looked perfect beforehand.

Manchen believes that with further experiments their group will be able to achieve entanglement among even more atoms than in their latest experiment