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Category: Physics

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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Time is not an illusion

Time is not an illusion

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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The tiny physics behind immense cosmic eruptions

The tiny physics behind immense cosmic eruptions

Zack Savitsky writes: During fleeting fits, the sun occasionally hurls a colossal amount of energy into space. Called solar flares, these eruptions last for mere minutes, and they can trigger catastrophic blackouts and dazzling auroras on Earth. But our leading mathematical theories of how these flares work fail to predict the strength and speed of what we observe. At the heart of these outbursts is a mechanism that converts magnetic energy into powerful blasts of light and particles. This transformation…

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It’s time to take quantum biology research seriously

It’s time to take quantum biology research seriously

Clarice Aiello writes: Imagine healing an injury by applying a tailored magnetic field to a wound. This outcome might sound fantastical, but researchers have shown that cell proliferation and wound healing, among other important biological functions, can be controlled by magnetic fields with strengths on the order of those produced by cell phones. This kind of physiological response is consistent with one caused by quantum effects in electron spin-dependent chemical reactions. However (and it’s a big however), while researchers have…

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Monist philosophy and quantum physics agree that all is one

Monist philosophy and quantum physics agree that all is one

Heinrich Päs writes: ‘From all things One and from One all things,’ wrote the Greek philosopher Heraclitus some 2,500 years ago. He was describing monism, the ancient idea that all is one – that, fundamentally, everything we see or experience is an aspect of one unified whole. Heraclitus wasn’t the first, nor the last, to advocate the idea. The ancient Egyptians believed in an all-encompassing but elusive unity symbolised by the goddess Isis, often portrayed with a veil and worshipped…

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Reality has no ultimate building blocks

Reality has no ultimate building blocks

Tuomas Tahko writes: Philosophers and scientists alike often talk about “fundamentality” or the “fundamental level”. We might say that, fundamentally, everything is made of waves or that quantum field theory is as close to a fundamental theory as we currently have. More colloquially, we might say that ultimately everything is made of the fundamental “building blocks” of reality, whatever they may be – fields, particles, or something else. The thought is that these building blocks compose everything else, and so…

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‘QBism’: quantum mechanics is not a description of objective reality – it reveals a world of genuine free will

‘QBism’: quantum mechanics is not a description of objective reality – it reveals a world of genuine free will

In a cubist painting, reality is more than a single perspective can capture. wikipedia, CC BY-SA By Ruediger Schack, Royal Holloway University of London What does quantum mechanics, the most successful theory ever proposed by physics, teach us about reality? The starting point for most philosophers of physics is that quantum mechanics must somehow provide a description of the world as it is independently of us, the users of the theory. This has led to a large number of incompatible…

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Are world happiness rankings culturally biased?

Are world happiness rankings culturally biased?

Emiliana R. Simon-Thomas writes: Every year, the World Happiness Report ranks 146 countries around the globe by their average level of happiness. Scandinavian countries usually top the list, the U.S. falls someplace in the mid-teens, and war-torn and deeply impoverished countries are at the bottom. The happiness scores come from a survey of life satisfaction, which goes something like this: Considering your life as a whole and using the mental image of a ladder, with the best possible life as…

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Shadows in the Big Bang afterglow reveal invisible cosmic structures

Shadows in the Big Bang afterglow reveal invisible cosmic structures

Zack Savitsky writes: Nearly 400,000 years after the Big Bang, the primordial plasma of the infant universe cooled enough for the first atoms to coalesce, making space for the embedded radiation to soar free. That light — the cosmic microwave background (CMB) — continues to stream through the sky in all directions, broadcasting a snapshot of the early universe that’s picked up by dedicated telescopes and even revealed in the static on old cathode-ray televisions. After scientists discovered the CMB…

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The multiverse: Our universe is suspiciously unlikely to exist – unless it is one of many

The multiverse: Our universe is suspiciously unlikely to exist – unless it is one of many

Do universes pop up as bubbles from a multiverse? arda savasciogullari/Shutterstock By Martin Rees, University of Cambridge It’s easy to envisage other universes, governed by slightly different laws of physics, in which no intelligent life, nor indeed any kind of organised complex systems, could arise. Should we therefore be surprised that a universe exists in which we were able to emerge? That’s a question physicists including me have tried to answer for decades. But it is proving difficult. Although we…

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