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Testing quantum collapse theory with the XENONnT dark matter detector

Theories of quantum mechanics predict that some particles can exist in superpositions, which essentially means that they can be in more than one state at once. When a particle’s state is measured, however, this superposition appears to “collapse” into a single outcome; a phenomenon often referred to as the “measurement problem.”

In recent years, various theoretical physicists have tried to explain why and how this collapse happens. This led to the introduction of various models, such as the Continuous Spontaneous Localization (CSL) and Diósi–Penrose models.

Both these models predict that spontaneous quantum collapse would also lead to the emission of faint X-ray radiation. The experimental detection of this radiation would thus provide evidence of these theories’ validity.

Why The Multiverse Could Be Real

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The multiverse pops out of quite a few theories in physics, and has been proposed as a solution to certain vexing problems. But it’s also been argued that the very idea of a multiverse is just bad science. That it’s unfalsifiable and a dead-end to inquiry and as bad a violation of Occam’s razor as you could imagine. But the multiverse might also exist. Can something that exists be bad science?

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A new way to read the universe could sharpen understanding of cosmic expansion and dark energy

An international team led by researchers at the Institute of Cosmos Sciences of the University of Barcelona (ICCUB) has developed a new method that could significantly improve our understanding of the expansion of the universe and the nature of dark energy.

The study, published in Nature Astronomy, presents a powerful framework called CIGaRS that allows scientists to extract more information from exploding stars known as Type Ia supernovae, primarily through imaging rather than costly spectroscopic observations. The results pave the way for making the most of the vast amount of data expected from the next generation of astronomical surveys, especially from the Vera C. Rubin Observatory.

What If Black Holes ARE Dark Energy?

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We tend to imagine there are connectings between things that we don’t understand. Quantum mechanics and consciousness, aliens and pyramids, black holes and dark matter, dark matter and dark energy, dark energy and black holes. Usually there’s no real relationship whatsoever, but this last pair—black holes and dark energy being the same thing—has received some recent hype in the press. Let’s see if it might actually be true.

Episodes referenced companion playlist: • what if black hole ARE dark energy? | comp…

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Understanding how lasers can rapidly magnetize fusion plasmas

The mechanism that can cause a rapidly expanding plasma—the superhot state of matter harnessed in fusion energy systems—to spontaneously generate its own magnetic fields was identified through a new set of simulations. This improves our understanding of naturally occurring plasmas in our universe and advances the development of fusion systems based on an approach called direct-drive inertial fusion.

In a direct-drive inertial fusion system, powerful lasers compress a small, fuel-filled capsule, heating it until fusion reactions occur. Unexpected magnetic fields can change how heat moves through the plasma in ways that existing simulation tools can miss. Accurate simulations are critical to designing fusion systems that will behave as expected and deliver net energy on a long-term basis.

In laboratory experiments, researchers found that high-powered lasers can vaporize a solid target in an instant, turning it into plasma that rapidly expands. Experiments have repeatedly detected very strong magnetic structures emerging from this expanding plasma, but the precise origin of these fields has long been a matter of debate.

Sean Carroll, CalTech, John’s Hopkins, Santa Fe Institute

One of the great intellectual achievements of the twentieth century was the theory of quantum mechanics, according to which observational results can only be predicted probabilistically rather than with certainty. Yet, after decades in which the theory has been successfully used on an everyday basis, most physicists would agree that we still don’t truly understand what it means. Sean Carroll will discuss the source of this puzzlement, and explain why an increasing number of physicists are led to an apparently astonishing conclusion: that the world we experience is constantly branching into different versions, representing the different possible outcomes of quantum measurements. This could have important consequences for quantum gravity and the emergence of spacetime.

Sean Carroll is a research professor at CalTech, Homewood Professor of Natural Philosophy at John’s Hopkins University, and Fractal Faculty at SFI. His research focuses on fundamental physics and cosmology, quantum gravity and spacetime, philosophy of science, and the evolution of entropy and complexity. He’s authored “Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime;” “The Big Picture;” “The Particle at the End of the Universe;” “From Eternity to Here;” and the textbook “Spacetime and Geometry.”

Something Disturbing Happens When You Solve Einstein’s Equations This Way

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Kurt Gödel discovered a solution to General Relativity that allows time travel without any exotic physics, revealing that the theory doesn’t actually guarantee a consistent chain of cause and effect. His “Gödel universe” shows that under certain conditions, the structure of spacetime itself can loop back on itself—blurring the line between past and future and exposing a deep limitation in our understanding of reality.

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Hosted by matt o’dowd written by matt o’dowd post production by leonardo scholzer directed by andrew kornhaber associate producer: bahar gholipour executive producer: andrew kornhaber executive in charge for PBS: maribel lopez director of programming for PBS: gabrielle ewing assistant director of programming for PBS: mike martin.

Is the Large Magellanic Cloud a First-Time Visitor?

Our most massive satellite galaxy, the Large Magellanic Cloud (LMC), has been the center of a heated debate in the astrophysics community over the last few years. That debate centers on whether this is the LMC’s first or second “pass” by the Milky Way itself — and it has huge implications for the evolution of our galaxy given the disruption such a large grouping of stars has. A new paper from Scott Lucchini, Jiwon Jesse Han, Sapna Mishra, and Andrew J. Fox and his co-authors, currently available in pre-print on arXiv, provides what they claim to be definitive evidence that this is, in fact, the first time LMC has encountered the Milky Way.

To understand the debate, it’s best to look at its history. For decades, there was an ongoing debate about the orbital path of the LMC. The discussion centered around a collisionless N-body dynamics model that tracked stars and their gravity. But back in 2024, physicist Eugene Vasiliev released a stunning paper that presented an argument that the LMC might have first passed the Milky Way 6–8 billion years ago at a distance of roughly 100 kiloparsecs.

Upon release of that paper, the debate was reignited. Vasiliev posited that, if the Milky Way’s dark energy halo was anisotropic (meaning the velocities of dark matter particles are skewed in certain directions), the current speed and position of the LMC would align perfectly with a “second pass” orbit. Dr. Lucchini and his co-authors are firmly on the other side of that argument.

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