'Avengers: Endgame': We Asked an Actual Physicist About the Quantum Realm

The Quantum Realm and Pym Particles are two pieces of the Marvel Cinematic Universe that cause many fans to scratch their heads before simply accepting the science and moving on with the rest of their movie. Certainly there's no such concoction that can shrink you however small you want, right? There's definitely not an alternate dimension out there where time and space doesn't exist, you probably think — and rightfully so. Leading up to Avengers: Endgame, we decided to speak with a physicist who knew all about quantum mechanics to try comparing real-life scientific theories and laws to what you'll see on screen this week.

When it comes to the Quantum Realm within the MCU, Hank Pym (Michael Douglas) has been studying it for its unlimited use of energy. So far, we've seen the alternate dimension three times -- in brief occasions during both Ant-Man and Doctor Strange and then it served as the basis for Ant-Man and the Wasp. From using it to sneak between dimensions, to the introduction of time vortexes, the movie version has essentially treated it as the ultimate MacGuffin.

Enter quantum physicist Dr. Sumanta Tewari. Dr. Tewari is an associate professor of physics and astronomy at Clemson University, where his research focuses on quantum computation and condensed matter theories. First things first, we wanted to compare what real-life quantum mechanics look like compared to how they're portrayed by Pym in the MCU.

"Like you are sitting there, I am sitting here. I am talking to you. These are classical intuitions," Tewari explains. "But they are classical only because we are large systems. If you could miniaturize us and take us to very small temperatures, very low temperatures, then we'll go on by quantum mechanics."

That makes sense, right? Quantum mechanics is the research of the smallest possible particles in the universe — subatomic particles — something completely in line with Pym and his namesake particles. Drilling it down, the physicist gives us a real-world example.

Say you're watching the Olympics and tune into a track race. You're observing a runner and note that they're starting at a certain point on the track. Judging by their current location and the velocity they're traveling, we can use physics to determine the location the runner will move to next. Where the situation becomes different, however, is when you look at it using quantum mechanics.

What quantum mechanics tell us is that the runner in this scenario isn't given a static point in space moving with a certain velocity. Instead, the runner's location is given in terms of a wave function. What that means, is that the runner's location is entirely dependent on the wave they're traveling.

Think about it on a macro level and look at the ocean and a wave of water. If the wave is 20 feet tall, you can either be 20 feet in the air or you can be in the trough below the surface of the water and it's likely to change in a microsecond. In short, that's what the study of quantum mechanics is all about.

"There's a rule called Born's rule that says that if you make a measurement of any property of the electron or any quantum mechanical particle, then the measurement outcomes will have certain probabilities," Tewari says. "So for instance, if I make a measurement of the electron's position, then the electron is described as a wave, which means the wave function is somewhere that has a larger value and somewhere it has a smaller value."

Using our example, that larger value Tewari mentions would be the ocean's crest while the smaller value would be the ocean's trough.

Once we completed Quantum Mechanics 101, we tried to make sense of the MCU's version of the Quantum Realm. As fate would have it, a thing such as the quantum realm technically exists in real life. You might be a bit heartbroken, however, to find out that it's not something you or I could use to travel through the space-time continuum. Believe it or not, you and I are in the quantum realm right now. Scientifically speaking, a quantum realm is a place where the laws of quantum mechanics are valid.

Dr. Tewari explains that this idea has since branched into theories about the existence of a multiverse. In this theory, particles in one universe are replicated in another using, you guessed it, the idea of quantum mechanics.

"It makes you feel like quantum mechanics gives you a bizarre idea that everything can be everywhere. I mean, at least everything has a certain probability of being everywhere," Tewari reflects. "Now this, that is that everything can be everywhere, this is, at the very basic level, is connected to this idea of multiverse."

"The multiverse theory tells you that you make a measurement, you have a probability of the particle being here. But you do have a probability of the particle being somewhere else," he continues. "And all these are different realities, so you and the particle exist in one reality where you have found the particle to be somewhere. But you could, as well, with less probability, find the particle to be somewhere else, and then that is also a reality that exists in another universe that is not accessible to you."

If we're on Earth-Prime, for example, how the heck do we get to Earth-2 or Earth-616? Well, it's just a simple matter of breaking the laws of physics and disrupting the space-time continuum as it exists in its current form. Sounds easy enough, right?

"We are not really able to see our communicate without our universes, because we are in our own fishbowl of a universe. Now, in order to be able to communicate between these different universes, you have to break down, you have to break apart this curved space time," Dr. Tewari asserts. "This is probably not allowed by Einstein's theory of relativity [as] it would break some fundamental laws of physics, but I would say if you can break through the barriers of space time, then, you know, then it might be possible."

Shifting gears from quantum mechanics to physics, the conversation takes a quick detour into the world of time travel, something Tewari says is much more plausible than inter-dimensional travel. According to the physicist, time travel — at least in a general scientific sense — would be possible if you could move at the speed of light.

"If you could move at the velocity of light, then you will not age. Your age is not going to go up. Meaning, time will stand still for you if you could move at the velocity of light," the physicist admits. "In other words, what follows from here is that if you move faster and faster and faster, time would move slower and slower and slower for you. Now this is well defined theory and this you can actually test in an experiment."

Dr. Tewari uses a set of twins as an example. Say one remains on Earth and the other leaves to continually explore space at lightspeed for the next 20 years. When the brothers eventually reconvene on Earth, the one that stayed behind will be 20 years older while the other will only have aged a fraction of that, say five years.

Of course, you probably don't recognize the scenario as the classic time travel seen in movies or on television where someone dials in a year on their machine and instantly goess there. While traveling forward in time, in a sense, is theoretically possible, Tewari says that traveling back in time, at least with the knowledge scientists have now, goes against the fundamental laws of physics.

"Physicists, we kind of understand why going backwards in time is not going to be possible," he says. "Because in order to do that, you need to be able to move at [a] speed greater than the speed of light, and again, people have made experiments to prove that the speed of light is the highest speed in the universe."

Now before you invest your entire savings account into trying to build your own spaceship that can eclipse the speed of light, Tewari points out that as of right now, the only particles that have been able to accomplish such a feat are the subatomic particles created in particle accelerators such as the Illinois-based Fermilab.

There you have it, MCU fans. While the quantum realm exists in real life, it's somewhat glorified on screen, as expected, and theoretically, time travel is technically is possible — at least at a subatomic level. As Dr. Tewari puts it, the study of quantum technologies is going to serve as the foundation of scientific research for the next few decades or more.

In fact, Congress passed the National Quantum Initiative Act last December and it was signed into law just days later, giving American scientists $1.2 billion over the next five years to accelerate research in the field. Who knows, maybe someone will have a massive breakthrough over the next five years and we'll be able to hop forward in time ourselves, though you probably shouldn't get your hopes up.

Welcome to Earth's Mightiest Week! From April 22nd to April 26th, ComicBook.com is celebrating the culmination of the Marvel Cinematic Universe so far with a series of exclusive articles, lists, arguments, and more. If you'd like to check out some of our other offerings from this week, you can click the image above.