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Category: particle physics – Page 264

Imagine a universe with extremely strong gravity. Stars would be able to form from very little material. They would be smaller than in our universe and live for a much shorter amount of time. But could life evolve there? It took human life billions of years to evolve on Earth under the pleasantly warm rays from the Sun after all.

Now imagine a with extremely weak gravity. Its matter would struggle to clump together to form stars, planets and—ultimately—living beings. It seems we are pretty lucky to have gravity that is just right for life in our universe.

This isn’t just the case for gravity. The values of many forces and in the universe, represented by some 30 so-called fundamental constants, all seem to line up perfectly to enable the evolution of intelligent life. But there’s no theory explaining what values the constants should have—we just have to measure them and plug their numbers into our equations to accurately describe the cosmos.

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For decades, various physicists have theorized that even the slightest changes in the fundamental laws of nature would make it impossible for life to exist. This idea, also known as the “fine-tuned universe” argument, suggests that the occurrence of life in the universe is very sensitive to the values of certain fundamental physics. Alter any of these values (as the logic goes), and life would not exist, meaning we must be very fortunate to be here.

But can this really be the case, or is it possible that life can emerge under different physical constants, and we just don’t know it? This question was recently tackled by Luke A. Barnes, a postdoctoral researcher at the Sidney Institute for Astronomy (SIA) in Australia. In his book, “A Fortunate Universe: Life in a Finely Tuned Cosmos,” he and Sydney astrophysics professor Geraint F. Lewis argued that a fine-tuned universe makes sense from a standpoint.

The authors also summarized these arguments in an invited contribution paper, which appeared in the Routledge Companion to Philosophy of Physics (1st ed.) In this paper, titled “The Fine-Tuning of the Universe for Life,” Barnes explains how “fine-tuning” consists of explaining observations by employing a “suspiciously precise assumption.” This, he argues, has been symptomatic of incomplete theories throughout history and is a common feature of modern cosmology and .

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For decades physicists have been perplexed about why our cosmos appears to have been precisely tuned to foster intelligent life. It is widely thought that if the values of certain physical parameters, such as the masses of elementary particles, were tweaked, even slightly, it would have prevented the formation of the components necessary for life in the universe—including planets, stars, and galaxies. But recent studies, detailed in a new report by the Foundational Questions Institute, FQXi, propose that intelligent life could have evolved under drastically different physical conditions. The claim undermines a major argument in support of the existence of a multiverse of parallel universes.

“The tuning required for some of these physical parameters to give rise to life turns out to be less precise than the tuning needed to capture a station on your radio, according to new calculations,” says Miriam Frankel, who authored the FQXi report, which was produced with support from the John Templeton Foundation. “If true, the apparent fine tuning may be an illusion,” Frankel adds.

Over the last few decades, the subject of fine tuning has attracted some of the sharpest minds in physics. By probing the ’s physical laws and precisely pinning down the values of physical constants—such as the masses of elementary particles and the strengths of forces—physicists have discovered that surprisingly small variations in these values would have rendered the universe lifeless. This led to a puzzle: why are physical conditions seemingly tailored towards human existence?

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The Higgs boson doesn’t stick around for long. Once it is created in particle collisions, the famed particle lives for a mere less than a trillionth of a billionth of a second or, more precisely, 1.6 × 10-22 seconds. According to theory, that is, for so far experiments have only been able to set bounds on the value of the particle’s lifetime or to determine this property with a large uncertainty. Until now. In a new study, the CMS collaboration reports a value for the particle’s lifetime that has a small enough uncertainty to confirm that the Higgs boson does have such a short lifetime.

Measuring the Higgs boson’s lifetime is high on the wish list of particle physicists, because an experimental value of the lifetime would allow them not only to better understand the nature of the particle but also to find out whether or not the value matches the value predicted by the Standard Model of particle physics. A deviation from the prediction could point to new particles or forces not predicted by the Model, including new particles into which the Higgs boson would decay.

But it isn’t easy to measure the Higgs boson’s lifetime. For one, the predicted lifetime is too short to be measured directly. A possible solution entails measuring a related property called the mass width, which is inversely proportional to the lifetime and represents the small range of possible masses around the particle’s nominal mass of 125 GeV. But this isn’t easy either, as the predicted mass width of the Higgs boson is too small to be easily measured by experiments.

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How can we combat data theft, which is a real issue for society? Quantum physics has the solution. Its theories make it possible to encode information (a qubit) in single particles of light (a photon) and to circulate them in an optical fiber in a highly secure way. However, the widespread use of this telecommunications technology is hampered in particular by the performance of the single-photon detectors.

A team from the University of Geneva (UNIGE), together with the company ID Quantique, has succeeded in increasing their speed by a factor of twenty. This innovation, published in the journal Nature Photonics, makes it possible to achieve unprecedented performances in quantum .

Buying a train ticket, booking a taxi, getting a meal delivered: these are all transactions carried out daily via . These are based on payment systems involving an exchange of secret information between the user and the bank. To do this, the bank generates a , which is transmitted to their customer, and a private key, which it keeps secret. With the public key, the user can modify the information, make it unreadable and send it to the bank. With the private key, the bank can decipher it.

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In 2022, the physics Nobel prize was awarded for experimental work showing that the quantum world must break some of our fundamental intuitions about how the Universe works.

Many look at those experiments and conclude that they challenge “locality” – the intuition that distant objects need a physical mediator to interact. And indeed, a mysterious connection between distant particles would be one way to explain these experimental results.

Others instead think the experiments challenge “realism” – the intuition that there’s an objective state of affairs underlying our experience. After all, the experiments are only difficult to explain if our measurements are thought to correspond to something real.

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The Big Bang may have not been alone.

The Big Bang may not have been alone. The appearance of all the particles and radiation in the universe may have been joined by another Big Bang that flooded our universe with dark matter particles. And we may be able to detect it.

In the standard cosmological picture, the early universe was a very exotic place. Perhaps the most momentous thing to happen in our cosmos was the event of inflation, which at very early times after the Big Bang, sent our universe into a period of extremely rapid expansion. When inflation ended, the exotic quantum fields that drove that event decayed, transforming themselves into the flood of particles and radiation that remains today.

When our universe was less than 20 minutes old, those particles began to assemble themselves into the first protons and neutrons during what we call Big Bang Nucleosynthesis. Big Bang Nucleosynthesis is a pillar of modern cosmology, as the calculations behind it accurately predict the amount of hydrogen and helium in the cosmos.

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A team of researchers led by the University of Innsbruck have observed a quantum tunneling effect in experiments that build off 15 years of research into such reactions and marks the slowest charged particle reaction ever observed until now. But while such chemical reactions have only been theoretical up to this point, can it be achieved in real-world experiments?

“It requires an experiment that allows very precise measurements and can still be described quantum-mechanically,” said Dr. Roland Wester, who is a professor of theoretical *physics at the University of Innsbruck, and lead author of the study. “The idea came to me 15 years ago in a conversation with a colleague at a conference in the United States.”

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One of the most fundamental rules of physics, undisputed since Einstein first laid it out in 1905, is that no information-carrying signal of any type can travel through the Universe faster than the speed of light. Particles, either massive or massless, are required for transmitting information from one location to another, and those particles are mandated to travel either below (for massive) or at (for massless) the speed of light, as governed by the rules of relativity. You might be able to take advantage of curved space to allow those information-carriers to take a short-cut, but they still must travel through space at the speed of light or below.

Since the development of quantum mechanics, however, many have sought to leverage the power of quantum entanglement to subvert this rule. Many clever schemes have been devised in a variety of attempts to transmit information that “cheats” relativity and allows faster-than-light communication after all. Although it’s an admirable attempt to work around the rules of our Universe, every single scheme has not only failed, but it’s been proven that all such schemes are doomed to failure. Even with quantum entanglement, faster-than-light communication is still an impossibility within our Universe. Here’s the science of why.

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Published in the journal Quantum Science and Technology, Saleh’s research focused on a novel quantum computing technique that should — at least on paper — be able to reconstitute a small object across space “without any particles crossing.”

While it’s an exciting prospect, realizing his vision will require a lot more time and effort — not to mention next-generation quantum computers that haven’t been designed, let alone built yet. That is if it’s even possible at all.

Counterportation can be achieved, the study suggests, by the construction of a small “local wormhole” in a lab — and as the press release notes, plans are already underway to actually build the groundbreaking technology described in the paper.

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