An international team of scientists published a study that seems to contradict the basic laws of physics: to demontrates in a quantum computer a “time reversal procedure.”
With the use of electrons and under the laws of quantum mechanics, researchers from the Institute of Physics and Technology of Moscow (MIPT) with the help of colleagues in Switzerland and the United States, developed an experiment that also managed to calculate the probability of a free electron in interstellar space “reverse” to its recent past spontaneously.
“We have artificially created a state that evolves in a direction opposite to that of the thermodynamic arrow of time,” said Gordey Lesovik, head of the Quantum Information Physics Laboratory at MIPT and lead author of the study published in Scientific Reports.
For the innovative experiment, the scientists used a quantum computer composed of electron “qubits.”
A qubit is an information unit composed of a “one,” a “zero” or an “overlap” of both states.
The computer used an “evolution” program that made the qubits, over time, take on an increasingly complex changing pattern of zeros and ones.
Then, in this chaotic system, another program was used which modified the state of the quantum computer in such a way that it evolved “backwards,” from chaos to order. That is, it managed to get the qubits back to how they were initially.
To explain this phenomenon, the authors used the example of billiard balls. When a triangle racked up by the pool balls is hit, the balls disperse. What they achieved is that the billiard balls return to form the initial triangle, as if a video had been reversed.
But does not this contradict the laws of physics? From the point of view of quantum mechanics, the past and the future are so similar that they can be interchangeable, to the point that most of the laws of physics do not admit temporary distinctions, because they work exactly the same regardless if time is moving forward or backward
However, the Universe has a law that goes in only one direction: The Second Law of Thermodynamics, which describes the progression of order to disorder.
“Uncovering the origin of the arrow of time remains a fundamental scientific challenge. Within the framework of statistical physics, this problem was inextricably associated with the Second Law of Thermodynamics, which declares that entropy growth proceeds from the system’s entanglement with the environment. It remains to be seen, however, whether the irreversibility of time is a fundamental law of nature or whether, on the contrary, it might be circumvented,” explains Lesovik.
But this innovative experiment has not dismantled the Second Law of Thermodynamics. And the authors explain that this discovery is disturbing, but that much more research needs to take place and still much more time before they can begin taliking about time travel.
Now, the study could have immediate applications in improving the performance of quantum computers. In this experiment, a success rate of 85 percent was achieved with two qubits. When three qubits were involved, more errors occurred, resulting in a 50 percent success rate.
Researchers will now seek to decrease this error rate. “Our algorithm could be updated and used to test programs written for quantum computers and eliminate noise and errors,” Lesovik said.
