Time travel is possible…or is it? Can we go back in time and rectify our mistakes, or can we travel to the future to see what’s ahead? The answer remains as mysterious as what is inside the Bermuda triangle. Complicated questions like what is time travel? What is quantum gravity? How is time travel possible? All these will start to arise in the curious mind, and the need to know the answer grows, making it more interesting.
The Ultimate Definition of Time Travel
Moving across space near light speed is the only way to travel through time. In theory, a human travelling at such a high speed would experience time at a slower rate than someone standing stationary on a planetary body. Someone entangled in the quantum gravity of a black hole would experience the same effect.
Everyone can travel across time. Whether you want to or not, you do it at a constant rate of one second per second. You might assume there’s no connection between going in one of the three spatial dimensions at one foot per second.
However, Einstein’s theory of relativity states that we live in a four-dimensional continuum — space-time — in which space and time are interchangeable. Einstein discovered that the faster you move through space, the slower you move through time – in other words, you age more slowly. One of relativity’s central concepts is that nothing can travel faster than the speed of light, which is approximately 186,000 miles per second (300,000 kilometres per second) or one light-year per year.
However, you may approach it extremely near to it. If a starship flew at 99% of the speed of light, it would cover a light-year distance in just over a year.
Wormhole and Time Travel the Entanglement
However, for more dramatic results, we must examine much stronger gravitational fields, such as those surrounding black holes, which have the power to warp space-time to the point where it collapses in on themselves. The outcome is a “wormhole,” a term popularized by science fiction films but whose roots are in Einstein’s theory of relativity.
A wormhole essentially serves as a shortcut between two points in space-time. You go into one black hole and come out of another in a different location. Unfortunately, Hollywood makes it seem like a more useful mode of transportation than it is.
It’s impossible in practice because the black hole’s gravity would shred you to pieces as you got close to it, but it is theoretically possible. The wormhole’s exit could be earlier than its entrance, which would cause you to find yourself in the past rather than the future. It is possible because we’re talking about space-time, not simply space.
Stephen Hawking, who was always suspicious of time travel into the past, developed his “chronology protection conjecture” — the theory that some as-yet-unknown physics law prohibits closed time-like curves from occurring. But that is just an educated estimate, and unless it is verified by real proof, we can only conclude that time travel is feasible.
The Bond Between Quantum Physics and Time Travel
Dr Samuel Beckett can go back in time in the movie Quantum Leap, but only to the years of his past. Although he swaps places with historical figures like Lee Harvey Oswald, others recognise him as that person. According to the show, Sam was reportedly the Secret Service agent who saved Jackie Kennedy. Once he has corrected what was wrong, he “leaps” into another body.
There are hand-waving explanations for how he leapt into the bodies, even though the show does not discuss why he did so. It has something to do with quantum mechanics, as the title would imply.
However, it is unlikely to be connected to true quantum leaps. When an electron jumps directly from one atom’s orbit to another without stopping in between, that is when it happens. And while that’s cool, it won’t result in time travel.
In quantum physics, there is a lot of debate over “time.” Time is significantly more malleable at the micro level, where waves and particles can behave similarly than in our visible classical physics universe.
Consider the clock on the wall. You can move the hands backwards, but this does not cause the time to reverse. Time moves on. However, in the quantum domain, things are easier. If we can express particle activity mathematically in one direction, we can also express it mathematically in the other.
In other words, time travel makes sense when viewed through a quantum lens. Whatever moves forward must also be capable of moving backwards.
We are aware that quantum mechanics makes time travel conceivable. Google made time crystals to demonstrate this, and many quantum computing paradigms rely on a prediction method that essentially uses molecular time travel to surface solutions.
But everyone knows that when it comes to quantum mechanics, we deal with particles acting unexpectedly. That’s not the same as pressing a button to summon an automobile from the 1980s to the Wild West.
That so, quantum time travel is still astounding in its own right. It would be impossible to create doughnuts that reappear on your plate after you eat them or beers that resurface in your glass no matter how many times you gulp them if time crystals were translated into something comparable in classical physics.
Objections Regarding the Time Travel
Two key problems lead us to believe that these equations might not be realistic. The first problem is a practical one: it appears that exotic matter, or matter with negative energy, is necessary for constructing a time machine.
Positive energy permeates every piece of matter we encounter daily; negative energy-containing substance is extremely rare. We know from quantum mechanics that it may generate such matter only in very small amounts and for brief periods.
However, no indication is given that creating unusual matter in substantial numbers is impossible. Furthermore, other equations that allow time travel without using exotic matter may be discovered. As a result, this problem could simply be a limitation of our current technology or understanding of quantum mechanics.
The other major obstacle is less practical but more significant: time travel violates logic in the form of time travel paradoxes. There are various sorts of such paradoxes, but consistency paradoxes are the most problematic.
Consistency paradoxes are a popular science fiction concept that occurs when an event leads to changing the past, but the change itself precludes the event from happening in the first place.
However, if you are unable to utilize the time machine, you are unable to go back in time and destroy it. As a result, it has not been destroyed, and you can go back in time and destroy it. In other words, the time machine is only destroyed if it is not destroyed.
This scenario is illogical and paradoxical since it cannot be both destroyed and not destroyed at the same time.
What About the Paradoxes, Then?
In science fiction, it’s popular to believe that paradoxes can be “made.” For this reason, time travellers are frequently cautioned not to make large changes to the past and to avoid encountering their past selves.
In physics, however, a paradox is not a real-world event; rather, it is a completely theoretical term that indicates an inconsistency in theory itself. In other words, consistency paradoxes do not show that time travel is a risky endeavour; they imply that it is just not possible.
Time travel can certainly lead to multiple histories and timelines. Time travel is only possible if our universe can handle the multiple histories and timelines coming into existence.
Sounds like a complete Marvel movie, and it is. Doctor Strange in the Multiverse of Madness somehow shows us the different timelines, whereas Avengers: Endgame showed us what time travel is.
Paradoxes are created, and after researching them, time travel seems to be possible. Quantum physics appears to imply this, according to Everett’s “many-worlds” interpretation, in which one history might “split” into numerous histories, one for each potential measurement outcome.
Parallel timelines and time travel are nearly always associated with science fiction, but now we have evidence that they must also be associated with reality. According to general relativity and quantum mechanics, time travel may be possible, but if it is, then numerous histories must also be conceivable.
Can Time Travel Be Possible Through Quantum Computing?
The idea of time travel is impossible in our day-to-day lives. What if we used quantum physics to define time travel? Well, many scientists view it as a “maybe” idea. We can assert the existence of time travel thanks to the theory of general relativity.
Due to recent developments in quantum computing, time-travelling quantum computers are now employed to solve every problem. Numerous researchers have presented their work on wormholes and quantum computing. In their work, they experiment with time-travelling particles to enable fractious computation.
Time travel is impossible in everyday life and doesn’t seem feasible to us. A few years ago, a researcher discovered that a (time travelling) quantum computer might solve various issues, including the NP-Complete problem.
The theory of relativity also introduced us to the concept of closed timeline curves, which may be thought of as routes between space and time. If we follow the closed timeline curves, a traveller can interact with their history.
Coordinating these closed temporal curves with quantum physics is a major challenge repeatedly explored. Regardless of the presence or absence of the closed temporal curve in spacetime, quantum computing supports a variety of phenomena.
Time travel can be thought of as a quantum communication link to the backward direction of spacetime. ‘Quantum Teleportation’ is an excellent example of a communication channel. When combined with shared entanglement and communication, quantum measurement enables quantum states to send and receive.
And by combining quantum teleportation and post-selection, a communication route opens up to the past. Entanglement occurs on both the forward and backward parts of the curve, causing quantum measurement to be substituted by post-selection, obviating the necessity for a communication channel, which gives rise to time travel.
What remains of the killing-your-earlier-self conundrum in general relativistic time travel worlds is that in some situations, the states on edgeless spacelike surfaces are ‘over-constrained,’ meaning that given the time-travel structure, one has less than the normal freedom in specifying conditions on such a surface.
In some cases, such states are ‘under-constrained,’ meaning that states on edgeless spacelike surfaces do not affect what happens elsewhere in the way that they do in other cases. There can also be a combination of the two types of situations. The amount to which states are over-constrained and under-constrained in practical models is still unknown; however, neither would be unexpected.
The existing literature has mostly concentrated on the problem of over-constraint, which is frequently considered either a metaphysical or an epistemological barrier to the possibility of time travel in our universe.
While it is true that our world would seem very different if states were overconstrained, under constraint appears to be at least as strange as over-constrained. Nonetheless, neither explicitly excludes the notion of time travel.
If time travel caused contradictions, it would solve the problem. And, certainly, most time-travel myths in popular culture are logically incoherent: one cannot “alter” the past to be different from what it was because the past (like the present and the future) only occurs once.
But if the only criteria are logical coherence, it appears too simple. A skilled author can create a logical time-travel scenario in which everything occurs only once and consistently.
It is simply too cheap: logical coherence is a relatively weak requirement, and many things we consider metaphysically impossible are logically coherent. Similarly, even if all of our consistency conditions are met, this does not imply that time travel is physically viable; rather, some specific physical factors cannot rule it out.
Demonstrating time travel’s reality would be the only serious proof of its possibility. For, if we agree that there is no genuine time travel in our universe, the hypothesis that there might have been entailing postulating a significant difference from reality, a difference unlike anything we could know ourselves.
We’re not sure what the possible substance would be if one were to either maintain or deny the possibility of time travel in these conditions unless one simply meant that some predefined set of limitations doesn’t rule the possibility out.
As Aristotle’s idea of water demonstrates, conceptual and logical “possibility” does not imply actual possibility. What exactly such a full-blooded sense would be in the case of time travel, and whether there would be the reason to suppose it would exist, remain unknown to us.
If you liked this article, check out: ‘What If You Meet Your Alternate Versions In The Multiverse?’