Physicists simulate time travel using quantum entanglement

The quantum world operates by different rules than the classical world we buzz around in, which allows the imaginary to become strangely general. Now, a team of physicists has used quantum entanglement to simulate a closed time-like curve – in layman’s terms, time travel.

Before we go any further, I will emphasize that this was fake; No quantum particle has ever gone back in time. research was a thoughtexperiment, a term popularized by Einstein to describe conceptual studies conducted in lieu of actual tests – a useful thing when one is testing physics at its limits, such as particles moving at the speed of light. But according to the team, “effective time travel” was achieved in the simulation. recent paper in Physical Review Letters, thanks to a well-known strange way in which quantum particles can interact.

that interaction is called very critical situation, and it describes when the properties of two or more quantum particles are defined by each other. This means that knowing the properties of one entangled particle gives you information about the other, regardless of the distance between the two particles; Their entanglement is at the quantum level, so a small thing like their physical distance has no impact on the relationship. Space is big and time is relative, so a change in a quantum particle on Earth that is entangled with a particle near a black hole 10 billion light years away would mean changing the behavior of something in the distant past.

Recent research explores the possibility of closed-timelike curves, or CTCs – an imaginary path back in time. The curve is a world line – the arc of a particle in space-time during its existence – that moves backwards. Steven Hawking gave his presentation 1992 “Chronology Preservation Conjecture” paper The laws of physics do not allow the existence of closed time-like curves – thus, time travel is impossible. “Nevertheless,” the recent study authors wrote, “they can potentially be simulated by quantum-teleportation circuits.”

The team’s Gedanken experiment is as follows: Physicists conducted a photonic probe through quantum interactions, which yielded a certain measurable result. Based on that result, they can determine what input will yield the optimal outcome – hindsight is 20/20, just like you might see when looking at a graded test. But because the result was obtained from a quantum operation, rather than being stuck with a less-than-optimal result, researchers can change the values ​​of the quantum probe through entanglement, leading to a better result despite the operation having already been performed. . Kapiche?

In the simulation, the apparent time travel effect occurred one time out of four – its failure rate was 75%. To address the high failure rate, the team suggests sending large numbers of entangled photons, using a filter to ensure that photons with the right information get in while filtering out old particles.

“The experiment we describe seems impossible to solve with standard (not quantum) physics, given the normal arrow of time,” David Arvidsson-Shkur, a quantum physicist at the University of Cambridge and lead author of the study, said in an email. Follows.” To Gizmodo. “Thus, it appears as if quantum entanglement can produce instances that effectively look like time travel.”

The behavior of quantum particles – in particular, the ways in which those behaviors differ from macroscopic phenomena – are a useful tool for physicists to probe the nature of our reality. Entanglement is one aspect of how quantum things operate according to various laws.

Last year, Another group of physicists claimed They managed to create a quantum wormhole – basically, a portal through which quantum information can travel instantaneously. A year ago, a team Synchronized drums as wide as a human hair Using entanglement. And Nobel Prize in Physics 2022 We went to three physicists to inquire about quantum entanglement, which is clearly an important topic to study if we are to understand how things work.

The simulation provided the Recent team with a means to investigate time travel without worrying about whether it is actually allowed by the laws of the universe.

“Whether closed time-like curves exist in reality, we do not know. The laws of physics we know allow for the existence of CTCs, but those laws are incomplete; Most obviously, we have no theory of quantum gravity,” study co-author Nicole Younger Halpern, a physicist at the National Institute of Standards and Technology and the University of Maryland at College Park, said in an email to Gizmodo. “Regardless of whether true CTCs exist or not, one can use entanglement to emulation CTC, as others showed before writing our paper.”

In 1992, a few weeks before Hawking’s paper was published, physicist Kip Thorne presented a paper at the 13th International Conference on General Relativity and Gravitation. Thorne concluded that, “It may turn out that chronology on macroscopic length scales is No always preserved, and even if the chronology Is Macroscopically conserved, quantum gravity can give finite probability amplitudes for microscopic space-time histories with CTCs. In other words, whether or not time travel is possible is a question beyond the bounds of classical physics. and since then Quantum gravity remains an elusive thingThe jury is out on time travel.

But in a way, whether or not closed-time-like curves exist in reality is not that important, at least in the context of the new research. Importantly, the researchers think their Gedanken experiment provides a new way to interrogate quantum mechanics. This allows them to take advantage of the quantum field’s apparent disregard for the time continuum to obtain some fascinating results.

More: Scientists try to entangle tardigrades in quantum

(Tags to translate) time travel(T) quantum entanglement(T) National Institute of Standards and Technology(T) quantum gravity(T) quantum information science(T) quantum teleportation(T) Steven Hawking(T) closed time-like curve (T) Introduction Quantum Mechanics (T) Chronology Conservation Conjecture (T) Quantum Mechanics (T) Quantum Computing (T) Emerging Technologies (T) Kip Thorne (T) David Arvidsson-Shkur (T) Causality (T) Nicole Younger Halpern

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