Researchers at the University of Cambridge have demonstrated that they can mimic what would happen if one could travel back in time by playing with entanglement, a central concept in quantum mechanics that allows particles to be inherently linked.
Quantum entanglement is an intriguing phenomenon that occurs when two or more particles become correlated in such a way that the state of one particle cannot be described independently of the state of the other(s), even when they are separated by large distances. This means that the properties of one particle, such as its spin or polarization, are dependent on the properties of the other particle(s).
A gift from the past
“Imagine that you want to send a gift to someone: you need to send it on day one to make sure it arrives on day three,” said lead author David Arvidsson-Shukur, from the Hitachi Cambridge Laboratory. “However, you only receive that person’s wish list on day two. So, in this chronology-respecting scenario, it’s impossible for you to know in advance what they will want as a gift and to make sure you send the right one.
“Now imagine you can change what you send on day one with the information from the wish list received on day two. Our simulation uses quantum entanglement manipulation to show how you could retroactively change your previous actions to ensure the final outcome is the one you want.”
Entanglement’s ability to instantly reflect changes in one particle’s state in another particle’s state independent of their physical proximity is one of its most remarkable features. Albert Einstein is credited with using the phrase “spooky action at a distance” to describe what appears to be happening. Due to the fact that two particles can continue to interact even when separated, quantum physics offers a unique solution to time travel.
Co-author Nicole Yunger Halpern, researcher at the National Institute of Standards and Technology (NIST) and the University of Maryland, explained that what the scientists are proposing is the entanglement of two particles.
The first particle is the one used in an experiment. It then acquires new information which leads the experimentalist to manipulate the second particle to effectively alter the first particle’s past state. This process then changes the outcome of the experiment, linking the past to the present.
Linking quantum metrology
The theorists then linked quantum metrology to their model to make it relevant to technology. A common quantum metrology experiment involves shining photons onto an object of interest, and then subsequently registering them with a unique kind of camera. The photons must be prepared in a specific way before they reach the sample for this experiment to be effective. The scientists demonstrated that even if they discover the optimum way to prepare the photons after they have already reached the sample, they can still utilize simulations of time travel to alter the original photons.
“We are not proposing a time travel machine, but rather a deep dive into the fundamentals of quantum mechanics. These simulations do not allow you to go back and alter your past, but they do allow you to create a better tomorrow by fixing yesterday’s problems today,” said Arvidsson-Shukur.
ABOUT THE EDITOR
Loukia Papadopoulos <p>Loukia Papadopoulos is a journalist, writer, and editor with previous experience with the United Nations Momentum for Change, Leo Burnett and Al Arabiya English. She holds a D.E.C. in Pure and Applied Sciences from Marianopolis College, a B.A. in Communications and an M.Sc. in Geography, Urban and Environmental Studies from Concordia University.</p>
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