A new study suggests that subatomic particles called muons streamed through the atmosphere and fatally irradiated megafauna like the monster shark megalodon.
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Category: particle physics – Page 561
The production of entropy, which means increasing the degree of disorder in a system, is an inexorable tendency in the macroscopic world owing to the second law of thermodynamics. This makes the processes described by classical physics irreversible and, by extension, imposes a direction on the flow of time. However, the tendency does not necessarily apply in the microscopic world, which is governed by quantum mechanics. The laws of quantum physics are reversible in time, so in the microscopic world, there is no preferential direction to the flow of phenomena.
One of the most important aims of contemporary scientific research is knowing exactly where the transition occurs from the quantum world to the classical world and why it occurs — in other words, finding out what makes the production of entropy predominate. This aim explains the current interest in studying mesoscopic systems, which are not as small as individual atoms but nevertheless display well-defined quantum behavior.
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A scientific collaboration has released a concept design for the Large Hadron Collider’s successor, an enormous new experiment that would sit inside a hundred-kilometer (62-mile) tunnel.
The design concept plans for two Future Circular Colliders, the first which would begin operation perhaps in 2040. The ambitious experiments would hunt for new particles with collision energies 10 times higher than those created by the Large Hadron Collider (LHC). The concept design is the first big milestone achieved by the scientific collaboration.
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Australia’s New South Wales scientists have adapted single atom technology to build 3D silicon quantum chips – with precise interlayer alignment and highly accurate measurement of spin states. The 3D architecture is considered a major step in the development of a blueprint to build a large-scale quantum computer.
They aligned the different layers in their 3D device with nanometer precision – and showed they could read out qubit states with what’s called ‘single shot’, i.e. within one single measurement, with very high fidelity.
“This 3D device architecture is a significant advancement for atomic qubits in silicon,” says Professor Simmons.
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One mysterious number determines how physics, chemistry and biology work. But controversial experimental hints suggest it’s not one number at all.
By Michael Brooks
IT IS a well-kept secret, but we know the answer to life, the universe and everything. It’s not 42 – it’s 1/137.
This immutable number determines how stars burn, how chemistry happens and even whether atoms exist at all. Physicist Richard Feynman, who knew a thing or two about it, called it “one of the greatest damn mysteries of physics: a magic number that comes to us with no understanding”.
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While our choices and beliefs don’t often make sense or fit a pattern on a macro level, at a “quantum” level, they can be predicted with surprising accuracy.
The irrationality of how we think has long plagued psychology. When someone asks us how we are, we usually respond with “fine” or “good.” But if someone followed up about a specific event — “How did you feel about the big meeting with your boss today?” — suddenly, we refine our “good” or “fine” responses on a spectrum from awful to excellent.
In less than a few sentences, we can contradict ourselves: We’re “good” but feel awful about how the meeting went. How then could we be “good” overall? Bias, experience, knowledge, and context all consciously and unconsciously form a confluence that drives every decision we make and emotion we express. Human behavior is not easy to anticipate, and probability theory often fails in its predictions of it.
Enter quantum cognition : A team of researchers has determined that while our choices and beliefs don’t often make sense or fit a pattern on a macro level, at a “quantum” level, they can be predicted with surprising accuracy. In quantum physics, examining a particle’s state changes the state of the particle — so too, the “observation effect” influences how we think about the idea we are considering.
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When radiochemist Jennifer Shusterman and her colleagues got the first results of their experiment, no one expected what they saw: Atoms of a weird version of the element #zirconium had enthusiastically absorbed neutrons.
Zirconium-88 captures neutrons with extreme efficiency, and scientists don’t yet know why.
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How do you separate carbon dioxide from carbon monoxide? One way, showcased by a new study from Kanazawa University, is to use a bowl of vanadium. More precisely, a hollow, spherical cluster of vanadate molecules can discriminate between CO and CO 2, allowing potential uses in CO 2 storage and capture.
At the molecular scale, small objects can fit inside larger ones, just like in the everyday world. The resulting arrangements, known as host-guest interactions, are stabilized by non-covalent forces like electrostatics and hydrogen bonds. Each host will happily take in certain molecules, while shutting out others, depending on the size of its entrance and how much interior space it can offer the guest.
Anion structures of CH 2 Cl 2 (guest)-inserted V12 (left) and guest-free V12 are shown. Orange and red square pyramids represent VO 5 units with their bases directed to the center of the bowl, and the inverted VO 5 unit. Green and black spheres represent Cl and C, respectively. Hydrogen atoms of CH 2 Cl 2 are omitted for clarity. (Image: Kanazawa University)
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Hacker attacks on everything from social media accounts to government files could be largely prevented by the advent of quantum communication, which would use particles of light called “photons” to secure information rather than a crackable code.
Using light to send information is a game of probability: Transmitting one bit of information can take multiple attempts. The more photons a light source can generate per second, the faster the rate of successful information transmission.
“A source might generate a lot of photons per second, but only a few of them may actually be used to transmit information, which strongly limits the speed of quantum communication,” Bogdanov said.
For faster quantum communication, Purdue researchers modified the way in which a light pulse from a laser beam excites electrons in a man-made “defect,” or local disturbance in a crystal lattice, and then how this defect emits one photon at a time.
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