Physics

From Jesse Emspak at LiveScience: The world’s largest atom smasher has revealed a new kind of particle, and so far, it leads a charmed existence. The discovery of the particle, which is made up of two so-called charm quarks, validates the predictions of the Standard Model, the current reigning model of particle physics. The world’s largest atom smasher has revealed a new kind of particle, and so far, it leads a charmed existence. The discovery of the particle, which is made up of two so-called charm quarks, validates the predictions of the Standard Model, the current reigning model of particle physics. … The Xi joins a menagerie of other particles that form the world of the very small. The Xi Read More ›

From Charles Q. Choi at Space.com: For the first time ever, scientists have directly spotted a pair of supermassive black holes orbiting each other, a new study suggests. This orbital motion — which was noted in observations made over the course of a dozen years — may be the smallest-ever movement detected of an object across the sky, the researchers said. … The presence of these giant black holes so close together suggested that the galaxy in which they lie resulted from dozens of galaxies merging sometime in the past, the researchers said. This raises the possibility that the two black holes themselves might one day merge also, the scientists said. More. Better than fireworks. Happy Fourth of July to Read More ›

From Philip Ball at Aeon: It’s a strange idea that measurement needs explaining at all. Usually what we mean by a measurement seems so trivial that we don’t even ask the question. A ball has a position, or a speed, or a mass. I can measure those things, and the things I measure are the properties of the ball. What more is there to say? But in the quantum world things aren’t so obvious. There, the position of a particle is nothing more than a whole set of possible positions until the moment when it is observed. The same holds true for any other aspect of the particle. How does the multitude of potential properties in a quantum object turn Read More ›

From Sabine Hossenfelder at at Forbes: After an effort of more than 100 years and a collaboration involving over 1,000 scientists, we all celebrated. It was February 11, 2016, and LIGO had just announced their first direct detection of gravitational waves. Analysis of the data attributed the signal to a black hole merger that happened several billion light years away. But what if there wasn’t a signal at all, but rather patterns and correlations in the noise that fooled us into believing we were seeing something that wasn’t real? A group of Danish researchers just submitted a paper arguing that the celebration might have been premature. Hossenfelder is not convinced. Making sense of somebody else’s data is tricky, as I Read More ›

From the Economist: Although, like all Gedankenexperimente, this latest one cannot be conducted with current experimental technologies, all of the assumptions behind it have been so tested in the past. It therefore obeys both quantum mechanics and the theory of general relativity. But one big question nags. If the Gedankenexperimente that led to relativity relied on a linearity of time that the theory itself is now helping call into question, can those original thought experiments themselves be relied on? More. Time mayn’t be in as big trouble as the Economist is, fronting this stuff. See also: How naturalism rots science from the head down

Of course not. Not that you would know from the headline: From Jon Cartwright at New Scientist: Believe it or not, this burst of cosmological inflation, followed by a slower, tamer expansion, is the most sensible way to explain how the universe looks today. But there’s something missing: what did the inflating? The answer could be everywhere, and right under our noses. When a long-sought particle finally appeared a few years back, it seemed to close a chapter in physics without giving any clue about what happens next. Read between the lines, though, as some theorists recently have, and you see that the famous Higgs boson – the particle that gives mass, or inertia, to all other particles – might Read More ›

From Toni Airaksinen at the College Fix: Feminist researcher invents ‘intersectional quantum physics’ to fight ‘oppression’ of Newton: ‘Binary and absolute differences’ are ‘exploitative’ A feminist academic affiliated with the University of Arizona has invented a new theory of “intersectional quantum physics,” and told the world about it in a journal published by Duke University Press. Whitney Stark argues in support of “combining intersectionality and quantum physics” to better understand “marginalized people” and to create “safer spaces” for them, in the latest issue of The Minnesota Review. More. Paper. (pay wall) The abstract reads In this semimanifesto, I approach how understandings of quantum physics and cyborgian bodies can (or always already do) ally with feminist anti-oppression practices long in use. Read More ›

From theoretical physicist M. B. Paranjape at Physics Today: Another frequent concern expressed over the existence of negative mass is that it would cause an untenable instability of the universe. Stephen Hawking once told me that if negative mass existed, “the universe would be unstable and we would not be here to this day.” But negative mass exists only in an expanding universe, and because of energy conservation it can only be produced in positive–negative mass pairs. If there is a backreaction of the production of these pairs on the background cosmological energy, the production of negative mass should drive that energy density to zero, thus terminating the possibility of its production and quenching any instability. This mechanism could offer Read More ›

From ScienceDaily: Paper. (paywall) PhD student Qingdi Wang has tackled this question in a new study that tries to resolve a major incompatibility issue between two of the most successful theories that explain how our universe works: quantum mechanics and Einstein’s theory of general relativity. The study suggests that if we zoomed in-way in-on the universe, we would realize it’s made up of constantly fluctuating space and time. “Space-time is not as static as it appears, it’s constantly moving,” said Wang. … Unlike other scientists who have tried to modify the theories of quantum mechanics or general relativity to resolve the issue, Wang and his colleagues Unruh and Zhen Zhu, also a UBC PhD student, suggest a different approach. They Read More ›

From Ethan Siegel at Forbes: This might seem like out-and-out science fiction, but not all of it belongs to the “fiction” category: traveling through time is the one thing in science that you can’t help yourself from doing no matter what you do! The question is how much you can manipulate it for your own ends, and control your motion through time. Physicist Siegel offers theories that enable forward or backward motion through tme but says But that’s a mathematical solution; does that mathematics describe our physical Universe, though? It appears not to be the case. The curvatures and/or discontinuities we’d need our Universe to have are wildly incompatible with what we observe, even near neutron stars and black holes: Read More ›

From Natalie Wolchover at Quanta: In recent years, a revolutionary understanding of thermodynamics has emerged that explains this subjectivity using quantum information theory — “a toddler among physical theories,” as del Rio and co-authors put it, that describes the spread of information through quantum systems. Just as thermodynamics initially grew out of trying to improve steam engines, today’s thermodynamicists are mulling over the workings of quantum machines. Shrinking technology — a single-ion engine and three-atom fridge were both experimentally realized for the first time within the past year — is forcing them to extend thermodynamics to the quantum realm, where notions like temperature and work lose their usual meanings, and the classical laws don’t necessarily apply. … “Many exciting things Read More ›

From Phys.org: A group of researchers from the Faculty of Physics at the University of Warsaw has shed new light on the famous paradox of Einstein, Podolsky and Rosen after 80 years. They created a multidimensional entangled state of a single photon and a trillion hot rubidium atoms, and stored this hybrid entanglement in the laboratory for several microseconds. The research has been published in Optica. In their famous Physical Review article, published in 1935, Einstein, Podolsky and Rosen considered the decay of a particle into two products. In their thought experiment, two products of decay were projected in exactly opposite directions—or more scientifically speaking, their momenta were anti-correlated. Though not be a mystery within the framework of classical physics, Read More ›

From George Musser, author of Spooky Action at a Distance and The Complete Idiot’s Guide to String Theory, at Nautilus, noting Neuroscience is weighing in on physics’ biggest questions. The physicists and philosophers I asked to comment on collapse driven by information integration are broadly sympathetic, if only because the other options for explaining (or explaining away) collapse have their own failings. But they worry that Integrated Information Theory is poorly suited to the task. Angelo Bassi, a physicist at the University of Trieste who studies the foundations of quantum mechanics, says that information integration is too abstract a concept. Quantum mechanics deals in the gritty details of where particles are and how fast they’re moving. Relating the two is Read More ›

From Nancy Atkinson at LiveScience: Now, researchers have produced what they say is the first composite image of a dark matter filament that connects galaxies together. … In their paper, they explained that in order to study the weak lensing signal of the dark matter filaments, they required two sets of data: a catalog of galaxy cluster pairs that were lensed, and a catalog of background source galaxies with accurate distance measurements. They combined lensing data from a multi-year sky survey at the Canada-France-Hawaii Telescope with information from the Sloan Digital Sky Survey that mapped luminous red galaxies (LRGs), which are massive, distant, and very old galaxies. … Hudson and Epps combined or “stacked” more than 23,000 galaxy pairs, all Read More ›

From Karla Lant at Futurism: The revelation that observing and measuring quantum effects changes their behavior is troubling, but it also suggests to many people that consciousness itself is part of quantum theory. Moreover, as humans creating AI that, for all its achievements still can’t master some of the things that come so easily to our own minds (at least not yet), we are bound to see a blurry reflection of ourselves in quantum computers, which promise to achieve so much more than ordinary computers ever could. However, it was the British physicist Roger Penrose who pointed out that, observer effect aside, quantum mechanics may be involved in consciousness. More specifically, he thought it might be possible that quantum events Read More ›