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Category: Physics

Synchronization is one of the fundamental phenomena of nature

Synchronization is one of the fundamental phenomena of nature

Any oscillator — a pendulum, a spring, a firefly, a human heart cell — wants to match up with its neighbors. Mathematicians recently showed that synchronization is inevitable in expander graphs, a type of network found in many areas of science. https://t.co/SM4cUWupJf pic.twitter.com/rINEz3lTuf — Quanta Magazine (@QuantaMagazine) February 3, 2024 Leila Sloman writes: Six years ago, Afonso Bandeira and Shuyang Ling were attempting to come up with a better way to discern clusters in enormous data sets when they stumbled…

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Time is not an illusion. It is an object with physical size

Time is not an illusion. It is an object with physical size

Sara Walker and Lee Cronin write: A timeless universe is hard to imagine, but not because time is a technically complex or philosophically elusive concept. There is a more structural reason: imagining timelessness requires time to pass. Even when you try to imagine its absence, you sense it moving as your thoughts shift, your heart pumps blood to your brain, and images, sounds and smells move around you. The thing that is time never seems to stop. You may even…

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Does quantum theory imply the entire Universe is preordained?

Does quantum theory imply the entire Universe is preordained?

Eddy Keming Chen writes: Was there ever any choice in the Universe being as it is? Albert Einstein could have been wondering about this when he remarked to mathematician Ernst Strauss: “What I’m really interested in is whether God could have made the world in a different way; that is, whether the necessity of logical simplicity leaves any freedom at all.” US physicist James Hartle, who died earlier this year aged 83, made seminal contributions to this continuing debate. Early…

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Supermassive black hole at the heart of the Milky Way is approaching the cosmic speed limit, dragging space-time along with it

Supermassive black hole at the heart of the Milky Way is approaching the cosmic speed limit, dragging space-time along with it

Live Science reports: The supermassive black hole at the heart of our galaxy isn’t just spinning — it’s doing so at almost maximum speed, dragging anything near it along for the ride. Physicists calculated the rotational speed of the Milky Way’s supermassive black hole, called Sagittarius A* (Sgr A*), by using NASA’s Chandra X-ray Observatory to view the X-rays and radio waves emanating from outflows of material. The spin speed of a black hole is defined as “a” and given…

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Don’t expect a ‘theory of everything’ to explain everything

Don’t expect a ‘theory of everything’ to explain everything

Dennis Overbye writes: What good are the laws of physics if we can’t solve the equations that describe them? That was the question that occurred to me on reading an article in The Guardian by Andrew Pontzen, a cosmologist at University College London who spends his days running computer simulations of black holes, stars, galaxies and the birth and growth of the universe. His point was that he and the rest of us are bound to fail. “Even if we…

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Will the universe ever stop expanding?

Will the universe ever stop expanding?

Sarah Scoles writes: From Earth, the night sky looks fairly static. Sure, the stars rotate from evening to evening, and the planets move among them. But from a terrestrial perspective, the celestial sphere appears essentially unchanging. Perception, though, is not reality: our eyeballs don’t hint that beyond nearby planets, stars and galaxies, everything is moving away from us. The universe is constantly expanding—at an ever faster rate. “When we say that the universe is expanding, we mean something pretty literal,”…

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Is there a crisis in cosmology?

Is there a crisis in cosmology?

Adam Frank and Marcelo Gleiser write: Not long after the James Webb Space Telescope began beaming back from outer space its stunning images of planets and nebulae last year, astronomers, though dazzled, had to admit that something was amiss. Eight months later, based in part on what the telescope has revealed, it’s beginning to look as if we may need to rethink key features of the origin and development of the universe. Launched at the end of 2021 as a…

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Quantum ‘yin-yang’ shows two photons being entangled in real-time

Quantum ‘yin-yang’ shows two photons being entangled in real-time

Live Science reports: Scientists have used a first-of-its-kind technique to visualize two entangled light particles in real time — making them appear as a stunning quantum “yin-yang” symbol. The new method, called biphoton digital holography, uses an ultra high-precision camera and could be used to massively speed up future quantum measurements. The researchers published their findings Aug. 14 in the journal Nature Photonics. Quantum entanglement — the weird connection between two far-apart particles that Albert Einstein objected to as “spooky…

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A hidden state between liquid and solid may have been found

A hidden state between liquid and solid may have been found

Science Alert reports: Glass might look and feel like a perfectly ordered solid, but up close its chaotic arrangement of particles more closely resemble the tumultuous mess of a freefalling liquid frozen in time. Known as amorphous solids, materials in this state defy easy explanation. New research involving computation and simulation is yielding clues. In particular, it suggests that, somewhere in between liquid and solid states is a kind of rearrangement we didn’t know existed. According to scientists Dimitrios Fraggedakis,…

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Why the empty atom picture misunderstands quantum theory

Why the empty atom picture misunderstands quantum theory

Mario Barbatti writes: The camera zooms in on the person’s arm to reveal the cells, then a cell nucleus. A DNA strand grows on the screen. The camera focuses on a single atom within the strand, dives into a frenetic cloud of rocketing particles, crosses it, and leaves us in oppressive darkness. An initially imperceptible tiny dot grows smoothly, revealing the atomic nucleus. The narrator lectures that the nucleus of an atom is tens of thousands of times smaller than…

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Researchers dig deep underground in hopes of finally observing dark matter

Researchers dig deep underground in hopes of finally observing dark matter

The inside of the LZ outer detector. The LZ is a super sensitive machine that may one day detect a dark matter particle. Matt Kapust, SURF, CC BY-SA By Hugh Lippincott, University of California, Santa Barbara Physicists like me don’t fully understand what makes up about 83% of the matter of the universe — something we call “dark matter.” But with a tank full of xenon buried nearly a mile under South Dakota, we might one day be able to…

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The paradox of time’s passage in modern physics

The paradox of time’s passage in modern physics

Avshalom Elitzur writes: It is perhaps the most fundamental ingredient of our experience that reality is constantly changing: Every moment, in its turn, seems to bring new events that did not exist before and that will vanish later. Every event, therefore, has three temporal properties that come one after another: i) before the event takes place it is a potential future event, subject in principle to interference; then, ii) when it actually happens, it is a fleeting present, and finally,…

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Measurement of electron’s ‘shape’ dims hopes for discovery of new particles

Measurement of electron’s ‘shape’ dims hopes for discovery of new particles

Science reports: A measurement of the humble electron has dimmed particle physicists’ long-held hopes of discovering exotic new particles. The finding, reported today in Science, confirms to greater precision than ever before that the distribution of electric charge in the electron is essentially round. The result implies that any new fundamental particles lurking undiscovered in the vacuum might be too massive for even the world’s biggest atom smasher, the Large Hadron Collider (LHC), to produce. “It’s a fantastic result,” says…

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Our simple magic-free recipe for quantum entanglement

Our simple magic-free recipe for quantum entanglement

Huw Price and Ken Wharton write: Almost a century ago, physics produced a problem child, astonishingly successful yet profoundly puzzling. Now, just in time for its 100th birthday, we think we’ve found a simple diagnosis of its central eccentricity. This weird wunderkind was ‘quantum mechanics’ (QM), a new theory of how matter and light behave at the submicroscopic level. Through the 1920s, QM’s components were assembled by physicists such as Werner Heisenberg and Erwin Schrödinger. Alongside Albert Einstein’s relativity theory,…

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Scientists thrill at first hints of cosmic ‘hum’ from giant gravitational waves

Scientists thrill at first hints of cosmic ‘hum’ from giant gravitational waves

Scientific American reports: After nearly two decades of listening, astronomers are finally starting to “hear” the rumbles of gravitational waves they believe emanate from the behemoths of our universe: supermassive black holes. The result comes from a National Science Foundation–sponsored initiative known as the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). Since 2004 NANOGrav has monitored metronomelike flashes of light from a Milky Way–spanning network of dead stars known as pulsars. Forged from the hearts of exploding massive stars,…

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We need quantum physics to see

We need quantum physics to see

Frank Wilczek writes: Many people, when they encounter the words “quantum mechanics,” go on the alert for esoteric paradoxes. And there are certainly plenty of those on offer. But sometimes, as my brilliant friend the physicist Sidney Coleman put it in a famous lecture at Harvard, quantum physics is “in your face.” To hear, we sense pressure waves, commonly called sound waves, which impinge on our eardrums. Channeled through some impressive natural mechanical engineering, sound waves set off vibrations on…

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