Numerous movies and theories about a time machine were made, but until now, science wasn’t really up to confirm whether reversing time is possible or not. Now, a new experiment shows how much flexibility we need in terms of making a distinction between the past and the future on a quantum scale.
This might not enable us to relive the past but could help us get a better understanding of why not. Researchers from Russia and the U.S. partnered to find a way to break or at least to bend the second law of thermodynamics, which is not as a hard of a rule but more of a guiding principle for the Universe.
The Second Law of Thermodynamics
The second law of thermodynamics says hot things get hotter with time as energy transforms and spreads out from regions where it’s most powerful. It is a principle that explains why a cup of coffee won’t stay hot in a cold room or why you aren’t allowed to patent a perpetual motion machine. It is also the closest principle we could come up with to tell us why we can remember what we did in the past but have no memory of the actions we will take in the future.
“That law is closely related to the notion of the arrow of time that posits the one-way direction of time from the past to the future,” said quantum physicist Gordey Lesovik from the Moscow Institute of Physics and Technology.
In theory, every other rule in physics can be reversed and still makes sense. For instance, you could observe a game of pool, and a collision between two balls won’t appear odd of you happen to see it in reverse. However, if you watch the balls roll out of pockets and form the starting pyramid, it would be a shocking experience. This is where the second law applies.
When it comes to the grand view of the game of pool, we should not expect to find lots of information in the laws of thermodynamics, but if we consider the tiny engines of reality, namely, solitary electrons, some loopholes show up.
Time Machine on a Quantum Level
Electrons are similar to information that takes a space; their details are characterized by what is known as the Schrödinger equation, which portrays the possibilities of an electron’s features as a wave of chance.
“However, Schrödinger’s equation is reversible,” said materials scientist Valerii Vinokur from the Argonne National Laboratory in the U.S. “Mathematically, it means that under a certain transformation called complex conjugation, the equation will describe a ‘smeared’ electron localizing back into a small region of space over the same time period.”
The team used the undetermined phases of particles in a quantum computer as well as some smart manipulation of the computer as their ‘time machine.’ Each of the states, or qubits, was placed into a simple phase that matched to a hand holding the ball. As soon as the quantum computer was turned on, these states rolled out into a number of possibilities.
By adjusting certain conditions in the computer’s setup, those possibilities were restricted in such a way that they wrapped the Schrödinger equation deliberately. To test the finding, the team launched the set-up again, as if kicking a pool table and watching the balls rearrange into the starting pyramid form. In approximately 85 percent of trials using just two qubits, this is what happened.
Discovering methods to push the limits of such physical principles on the quantum scale might help us better understand the reason behind the Universe’s ‘flow.’ The study was published in Scientific Reports.