The quantum trick sends light back and forth in time at the same time


For the first time, physicists have made it appear that a photon (a particle of light) is moving back and forth simultaneously in time, which scientists say could be useful for quantum computer calculations and further understanding of gravity quantum.

The demonstration, which has no immediate practical utility and has no connection to the popular sci-fi concept of time travel or communication with the past, is a clear example of how bizarre and intriguing time works at the quantum level. .

“Quantum Leap in Time”

Two different groups of physicists have put this seemingly counterintuitive property of the quantum world to the test: By splitting a photon, using a special optical crystal, the physicists have achieved what they describe as a “quantum time leap”, where a photon exists in both states temporary, back and forth.

Although our senses tell us that things are only one way or that, for example, time flows in one direction, the laws of quantum physics seem to have no regard for what we believe to be true.

Quantum superposition and CPT

So, as reported living science, the effect described by the scientists is the result of the convergence of two strange principles of quantum mechanics: quantum superposition, which allows tiny particles to exist in many different states, or different versions of themselves, simultaneously, until they are observed – such as Schrödinger’s cat thought experiment, in which a cat is in a box and is in both a dead and alive quantum state until the box is opened; and charge symmetry, parity, and time reversal (CPT), which states that any system containing particles will obey the same physical laws even if the charges, spatial coordinates, and time motions of the particles are reversed such as through a mirror.

Recent research has combined these two ideas and has suggested that it is possible to have photons in a superposition of states back and forth in time. Now, that idea has been proven experimentally.

The results of the twin experiments (one on October 31 and one on November 2) have been published on the preprint server arXivwhich means that the results have not yet been peer-reviewed.

The recent work of researchers does not allow us to change the past.  However, it could have some interesting real and theoretical applications. The recent work of researchers does not allow us to change the past. However, it could have some interesting real and theoretical applications.

“In a sense, quantum time reversal can be said to be Schrödinger’s cat for the direction of time,” said Giulio Chiribella, a quantum physicist at the University of Oxford and lead author of one of the two papers, according to the relationships. New scientist.

“Instead of being dead or alive, it’s about going forward or backward. A superpositioned quantum particle determines which one you are. Like the cat, you would end up in a forward and backward superposition. Which also means you’re not going forward or backward in time Or go back and forth at the same time,” he added.

How is it possible to go back and forth in time?

Time is one of those hard things to understand. And it is that it only seems to flow in a certain direction, which is believed to be due to the fact that time is related to the concept of entropy, which, according to the second law of thermodynamics, always increases in an isolated system such as the universe. This is what is known as the “arrow of time”.

“The arrow of time concept gives a word to the apparent one-wayness of time that we observe in the macroscopic world we live in,” he explains to living science Teodor Strömberg, physicist at the University of Vienna and first author of the other article.

“In fact, this is in tension with many of the basic laws of physics, which are generally time symmetric and therefore have no preferred time direction,” he added.

In this sense, as the scientific environment itself explains, while entropy is above all a statistical concept, and does not apply to individual subatomic particles, which instead seems to be true for all physical phenomena, and which has been applied up to now. it has been observed that holds for all interactions between particles, is the CPT symmetry (symmetry of charge, parity and time reversal).

Thus, particles that appear to be advancing in time are indistinguishable from those in a reflection system of time-regressing antiparticles. For example, antimatter was created out of matter during the Big Bang and doesn’t actually go back in time; it simply behaves as if it were following an arrow of time opposite to that of normal matter.

In short, the recent work of researchers does not allow us to change the past. However, it could have some interesting real and theoretical applications. For example, in developing a future theory of quantum gravity, which would combine general relativity and quantum mechanics, as it would need to include particles with mixed time orientations like those in this experiment.

On the other hand, the research could help on the quantum computer front, especially when it comes to logical operations, the crucial architecture of computing processes. The ability to perform quantum time jumps could allow for better performance and switching of inputs and outputs.

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