Simulations of time travel into the past improve scientific experiments

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Technological Innovation Website Editorial – 10/17/2023

Back to the past

It is possible to simulate what would happen if someone could travel back in time, going to the past instead of the future. To do this, simply use the well-known phenomenon of quantum entanglement, a feature of quantum mechanics that causes particles to be intrinsically connected and maintain this connection no matter how far apart they may later be.

These simulations bring great benefits to scientists, who can, in some cases, retroactively change the previous parameters of their experiments – the scientist’s past actions, in other words – and thus improve the results he obtains in the present.

Interestingly – although only in theory – the same may apply to speculators and gamblers in financial markets.

Although most of the fundamental laws of physics have no problem with the direction of time—they have time symmetry—whether or not particles can travel backwards in time remains a controversial topic among physicists. However, many simulations have already been performed on how these space-time loops would behave if they existed in reality.

Solve past problems

Now, a trio of physicists has linked the theory of time travel to quantum measurement, which uses quantum theory to make extremely sensitive measurements. The results show that quantum entanglement not only allows us to solve problems with proposals to go back in time, but above all to solve practical problems that seem impossible to solve.

“Imagine you want to send a gift to someone: you have to send it on the first day to make sure it arrives on the third day. However, you only receive that person’s wish list on the second day. So in this scenario, in terms of chronology, it is impossible for You get to know in advance what you want as a gift and make sure you send the right gift.

“Now imagine that you could change what you send out on day one with the wish list information you receive on day two. Our simulation uses quantum entanglement processing to show how you can retroactively change your past actions to ensure the end result is what you wanted,” explained Professor David Shakoor, from the University of Cambridge in the UK. United.

Time travel simulation

The simulation is based on quantum entanglement, which consists of strong connections that particles can share: if two particles get close enough to each other to interact, they can remain connected even after being separated by any distance. This is the basis of quantum computing, which uses interconnected particles to perform calculations too complex for classical computers.

“In our proposal, an experimental scientist links two molecules,” said Nicole Halpern, from the University of Maryland in the US. “The first particle is then sent back for use in the experiment. Upon obtaining new information, the experimentalist manipulates the second particle to effectively change the first particle’s previous state, changing the outcome of the experiment.”

To give their simulation technological relevance, physicists linked their model to quantum measurement. In a common quantification experiment, particles of light (photons) are directed at a sample and then recorded using a special type of high-speed camera.

For this experiment to be effective, the photons must be prepared in a certain way before reaching the sample. The researchers demonstrated that by simulating travel to the past, it is possible to discover how to better prepare the photons after they have already arrived in the sample, and go back to the past to retroactively change the original photons, thus obtaining greater efficiency in the sample. an experience.

Practical effects

The result is impressive, but for some reason physicists still don’t understand, the process only works once in every four attempts – in other words, a trip to the past has only a 25% chance of success. The team suggests that this inefficiency could be overcome by sending out a barrage of them, not just one photon at a time, and then using a filter to ensure the correct photons pass into the camera, while the filter rejects the rest of the photons. “Bad” photons.

“Think of our earlier analogy about gifts,” said Aidan McConnell of the Swiss Federal Institute of Technology (ETH). “Suppose sending gifts is cheap and we can send several packages on the first day. By the second day, we will know which gift we should have sent. When the packages arrive on the third day, one out of every four gifts will be correct, and we choose them by telling the recipient which ones to send.” Get rid of her.”

It sounds good enough for experiments with photons, and it is necessary to emphasize that the theory now described only works in these cases involving quantum particles. “We are not proposing a time travel machine, but rather a deep dive into the basics of quantum mechanics. This simulation does not allow you to go back and change your past, but it allows you to create a better tomorrow by solving the problems of yesterday,” said Shakur.

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