The advancements in science and technology have given life to fictional gadgets. Although such futuristic gadgets have kept us awestruck, we are still waiting for something that could turn back time. Imagine, if we are able to harness the power of time, we can bring technology from the 30th century. As a matter of fact, the foretold futuristic gadget won’t be “futuristic” enough for that time. However, to make this radical achievement we need a time machine.
While H.G Wells’ “Time Machine” and many other books have depicted how a time machine would look, none of them were realistic. But, that doesn’t mean the concept of the time machine is pure fiction. Believe it or not, a research team at the Moscow Institute of Physics and Technology(MIPT) is close to time reversal. However, before we get to that part, here is a short description of the time machine.
How realistic is the concept of the Time Machine?
Oftentimes, calling time machine as a device capable of “turning back time” is considered as vague, at least by physicists. Typically, scientists believe that there are multiple ways to achieve this feat. However, each of them is distinct from each other. For instance, Albert Einstein believed that folding the space-time fabric would open the portal to the future. Whereas, technophiles are banking on sophisticated computing devices for reversing time. To say, the essence of a time machine is blasphemous would need a high degree of scientific evidence. Hence, the concept of the time machine is realistic.
Quantum computers are the epitome of technological advancement. As a matter of fact, they tell us we have reached the pinnacle of computing technology. Practically, quantum computers can handle complex computations that conventional computers fail at. The reason for this is that quantum computers work on “qubits” as opposed to a classical bit. A classical bit can either be at state 0 or 1. That is, ON or OFF. However, a qubit can be both, as a result of its coherent superposition property. While the quantum computers handle the complex computations that even supercomputers can’t handle, scientists are leveraging this tech to find evidence for time travel. As a matter of fact, MIPT reversed the time by returning 3 qubits.
Time reversal and billiards
This is a thought experiment to illustrate the time-reversal. Essentially, if you record the collision and rebound of two identical billiard balls, and play it back, both the events would look plausible. Since it is hard to distinguish from the recording if it has been doctored. Now, record the case of cue ball breaking the pyramid. While doing this, billiard balls will scatter in all directions and hence it would be easier to distinguish the real-life scenario from reverse playback.
Time reversal algorithm
Now, what the researchers at MIPT did was to check whether time would spontaneously reverse itself. Scientifically, they had to examine a solitary electron in an empty interstellar space, instead of colliding the billiard balls. However, the concept of billiard balls unfolds into a much more chaotic timescale. In the sense, as the process proceeds, it would become more complex. Hence, to simulate this thought experiment, instead of working with an electron, the scientists observed the state of IBM quantum computers.
To explain what they did in simple terms, let us discretize the process in 4 stages.
Stage 1: Order
A quantum computer is composed of two or three basic elements called superconducting qubits. At the first stage, the qubits are initialized to ground state, i.e., 0. This is analogous to the rack of billiard balls assembled before the break or, an electron localized in a small region. This is a highly ordered configuration and forms the base for the rest of the operations. To clarify, if the qubit isn’t initialized it will have the probabilistic and chaotic state of either 0 or 1. This is best explained by “The Big Bang Theory” Sheldon Cooper.
Stage 2: Degradation
Here the stable state of a qubit turns chaotic(as expected). This can either occur naturally, as a result of the computer’s interaction with the environment. Or, it could happen after introducing an evolution program into the computer. This state is analogous to the electron being smeared out over a larger region or the rack being broken on the pool table. This stage will occur once again towards the end of the last stage so as to “reverse time”.
Stage 3: Time Reversal
This is where things get a bit complicated. Since the qubits are now degraded, the program will become more complex than ever. However, in this stage, researchers launch a special program onto the quantum computer that tries to order the qubit again. In the sense, to bring back the qubit to its ground state from its chaotic order. This is similar to how the randomly placed billiard balls are brought back to its position with a perfectly timed “kick”. Or, just like how a microwave background fluctuation would try to tame the smeared electron.
Stage 4: Regeneration
The final stage is accompanied by the launch of the evolution program. However, the researchers must ensure that the “kick” was delivered perfectly during the last stage before attempting this one. Surprisingly upon relaunching the program, the state of qubits refrain from its chaotic order but return back to its state. To put it into perspective, the billiard balls now retrace its trajectory in reverse playback to form the pyramid. Or just like how a smeared electron will eventually get localized.
Are we close to having a time machine?
Although their research does sound promising, many people consider it to be a mere coincidence. Despite their studies achieving a staggering 85% success rate, the analogy of quantum computing and real-life is complex. In the sense, things appear to be different going forward in time from how they were when the time is reversed.
“If you’re simulating a time-reversible process on your computer, then you can ‘reverse the direction of time’ by simply reversing the direction of your simulation,” Scott Aaronson, the Director of Quantum Information Centre said, before adding: “From a quick look at the paper, I confess that I didn’t understand how this becomes more profound if the simulation is being done on IBM’s quantum computer.”
One of the prominent quantum computing experts in the industry said, “I don’t know how useful this is … it doesn’t mean that these guys made a time machine…This is the type of hype that is going to give quantum computing a bad name.”. Right now, the only answer would be may, or maybe not. We may witness a time machine but, we can’t say for sure how long it would take.