Could we achieve teleportation through quantum tunnels

Quantum tunneling is absolutely insane, here is what you need to know

The quantum world just got a lot crazier.

To the uninitiated, quantum physics is a branch of science that describes the particles that make up matter and the forces with which they interact. If we have learned anything about the quantum world, it is this: The quantum world is strange. On an incredibly small scale, things don't behave intuitively. Physicists may well understand some of the math behind quantum physics, but that math can sometimes point to things that make them scratch their heads.

Niels Bohr once said that "those who are not shocked when they first encounter quantum theory, could not possibly have understood it".

In the quantum world it can be possible that entangled particles communicate faster than light, that tiny particles exist in several places at the same time, that particles come in and out randomly and that some particles can be "teleported" through walls like ghosts. Yes, the quantum world is strange. As you may have guessed, here we are going to focus on the last example, a process called quantum tunneling.

In its most basic and understandable explanation, quantum tunneling is the mechanical phenomenon in which a wave function can propagate through a potential barrier.

Imagine throwing a ball against the wall. It will hit the wall and ricochet backwards. If you roll it down a hill, when it hits the ground it will stay there. But on the quantum scale, particles will occasionally jump through the wall instead of "jumping back". While it may seem like a conspiracy from Marvel’s Avengers, the phenomenon was noticed as early as 1928 when two physicists wrote in Nature that particles sometimes "seem to slip through the mountain and escape the valley".

Your barrier is worthless here

Imagine that you and your little sister are fighting it out with Nerf Guns. You shoot at each other from different sides of the room. Your sister sits between a small, makeshift pillow "wall" a few feet high and a few feet wide while you keep shooting your rival Nemesis MXVII at her. Since this is the quantum world, you have millions of rounds loaded into your gun. In our case, 99.999% of your Nerf bullets will ricochet off the wall. However, a very small percentage will "teleport" to the other side of the wall and fire the final shots at your sister.

How did your Nerf pellets magically appear on the other side of the makeshift wall? You owe this to quantum tunneling. Our story begins here.

Particles have a chance to slip through the mountain and escape from the valley.

Since the first publication of the work on the idea of ​​quantum tunneling in 1928, researchers have been eager to learn more about this phenomenon, understand how it works, and get a direct answer to the age-old question of how fast "tunneling “Takes place.

The tunneling itself is a good reminder of how strange particles can behave at the quantum level. In quantum tunneling, a subatomic particle can appear on the opposite side of a barrier that it shouldn't be able to penetrate.

For example, suppose you were releasing a subatomic particle, like an electron or proton, into space on one side of a potential mound of energy. The particle doesn't have the energy to make it over the hill, so you are confident that the particle will stay in place. Nonetheless, the particle suddenly disappeared. As in the picture above, you can see that once you go to the other side of the hill the particle somehow made it over our hill. Particles crossing a tunnel can sneak through barriers like this one, and it could be more common than you think.

Indeed, quantum tunneling can be essential to such fundamental processes as photosynthesis. After discovering quantum tunneling, physicists realized that it actually solved many puzzles. It explained various chemical bonds and radioactive decays and how the hydrogen nuclei in the sun overcome their mutual repulsion and merge to produce sunlight.

Semiconductors, transistors and diodes would not work without them. And of course, quantum computing also includes tunneling. It turns out that particles slip through the mountain and quite often escape from the valley.

You need to grasp some of the key ideas in quantum physics before you can get into tunneling

One of the most significant differences between classical physics and quantum physics is that quantum physics is probabilistic. Let's go back to our example of the particle and hill barrier. If we tried to push a ball over the hill, we would always know exactly where the ball is. However, since we are using a particle, we do not know. In contrast to a ball, we cannot know exactly where a particle is at any given point in time.

You can thank Heisenberg's Uncertainty Principle for making this clear. It says that we can never know both the exact position and the time of a subatomic particle. Interestingly, this has nothing to do with a lack of suitable measuring instruments. Heisenberg's uncertainty principle seems to be a fundamental part of the nature of reality. There is some good news, however.

We are able to measure the probability of where a particle is at a given point in time, and to a very high degree. Quantum physicists model these probabilities with the help of a wave function. In short, a wave function is a description of the probability of finding an object in a certain place and at a certain time.

Still among us? One strange quality of waves is that they rarely stop when they hit something. Think about the sound. The sound waves of your music don't stop when they come into contact with solid objects. That's why they don't stop even when your door is locked. Your roommates can still hear you blowing your kpop.

Or, if it just didn't, the sunlight hitting your home would just stop and never warm your home. The same thing happens with the waveforms used to describe quantum particles. An object's wave function can extend into or beyond a barrier. Since this function describes the probability with which a particle will land in a certain space, it occasionally happens that this particle also lands on the other side of the barrier. Does it make sense?

Could You Walk Through Walls?

Maybe in theory, but most likely not. While this could be a cool (and dangerous) force, the likelihood of this happening is pretty close to zero. Jack Fraser, a graduate in physics from Oxford University, noted that "since the beginning of the universe [13.8 billion years ago] a trillion people could hit walls every second, a trillion times a second - and the probability that one of them runs through the wall is still so small that it is [practically] zero ”. Why? The probability that an object will pass through the wall is directly correlated to the mass of the object. The average person weighs around 70 kg; an electron weighs about 9 × 10-31 kg.

But if you feel like you are missing out on Quantum Party, all hope is not lost. Some research has suggested that quantum tunneling could take place in our bodies because the enzymes responsible for activating carbon-hydrogen bonds could promote hydrogen tunneling. Interestingly, one of these enzymes is responsible for converting ethanol to acetaldehyde, the compound that causes headaches, dizziness, and nausea after a night of partying. So maybe you won't miss the quantum party after all.

How fast does quantum tunneling take place?

This is the next logical question. However, this has been a hotly debated topic in the last few decades, along with the question of what happens to the particle when it “moves” through the barrier. Like many things in the quantum world, the answers to these questions are not easy.

Researchers have tried to measure the time it takes to build a tunnel before, with mixed and often questionable results, with some arguing that the event may be even faster than the speed of light. But just in the past year, scientists may have cracked the case with a historic 20-year research experiment.

In the published work, led by physicists from the Quantum Information Science Program at the Canadian Institute for Advanced Research, the researchers describe not only how they measured the process, but the number they received. “Quantum tunneling is one of the most puzzling quantum phenomena. And it's fantastic that we can actually study it that way now, ”says study co-author Aephraim Steinberg, co-director of the Quantum Information Science Program.

How did you do that? They used some of the most basic principles of quantum physics to make it possible. In their experiment, they used 8,000 rubidium atoms that were cooled to a billionth of a degree above zero Kelvin.

The atoms had to be at this temperature, otherwise they would have happened to be moving at high speed instead of staying in a small lump. The Canadian physicists used a laser to create a barrier and focused it so that the barrier was 1.3 microns, or about 2,500 rubidium atoms thick. Using another laser, the team pressed the rubidium atoms toward the barrier and moved them at a steady rate of about 3.8 mm (0.15 inches) per second. Most of the rubidium atoms bounced off the barrier. However, thanks to our old Pal tunnel, 3% of the atoms penetrated the barrier and made it to the other side.

The choice of rubidium was not accidental. It was used because the spin of the atom can be changed by lasers. The longer it took for the rubidium to tunnel through the barrier, the more the spin changed. By measuring the spin axis of an atom before and after it entered the barrier, the scientists were able to determine how long it took the atoms to tunnel. So how long did the process take? 0.61 milliseconds on average.

The result turned out to be a bit confusing as this is relatively slow in the quantum world, especially when you consider that previous work suggested that tunneling could be instantaneous. Regardless, it's another striking example of how an approach that could help demystify the quantum realm. The greatest insight is that it was possible to measure this event. “We are working on a new measurement in which we will make the barrier thicker and then determine the amount of precession at different depths. It will be very interesting to see whether the speed of the atoms is constant or not, ”says the team.

While quantum tunneling is not as puzzling as some of the falls further out, it is an important part of the nature of our world and universe. Understanding quantum tunneling could help us advance the development of new technologies such as quantum computing. It will be interesting to see what new quantum phenomena we can test.