With a Bose–Einstein condensate in a magnetic field, researchers can see hints of particle production in expanding space—and they can run the experiment more than once.
Confusing? It may sound so, but it isn’t actually. What Benini and Milan have done is apply the theory of the holographic principle to black holes. In this way, their mysterious thermodynamic properties have become more understandable: by focusing on predicting that these bodies have high entropy and looking at them in terms of quantum mechanics, which allows us to describe them as a hologram: they have two dimensions, in which gravity disappears, but they reproduce an object in three dimensions.
But there’s more. Much more.
According to the authors of the new studies, this is only the first step towards a deeper understanding of these cosmic bodies and the properties that characterize them when quantum mechanics intersects with general relativity.
What is the deepest nature of things? Our world is complex, filled with so much stuff. But down below, what’s most fundamental, what is ultimate reality? Is there anything nonphysical? Anything spiritual? Or only the physical world? Many feel certain of their belief, on each side of controversial question.
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From the slivers of natural magnetite used as the earliest magnetic compasses to today’s cryogenically cooled superconducting quantum interference devices, researchers have employed many diverse means to measure magnetic fields. Now Robert Cooper at George Mason University, Virginia, and colleagues have added two more [1]. Their instruments, which are variations on a high-precision instrument called an optically pumped atomic magnetometer, are the first demonstrations of “intrinsic radio-frequency gradiometers.” These devices are especially suited to measure weak, local radio-frequency sources while excluding background fields.
At the heart of an optically pumped atomic magnetometer lies a gas of alkali atoms whose spins are aligned by a circularly polarized laser—the optical pump. The presence of an external magnetic field perturbs the spin axis of these atoms, showing up as a change in the polarization direction of the probe beam—a second, linearly polarized laser that is also transmitted through the gas.
In the devices devised by Cooper and his colleagues, the probe beam makes multiple passes through the alkali gas, maximizing the device’s sensitivity to weak fields. In one setup, a high-power probe beam takes a single M-shaped route through the gas, passing twice through a pair of vapor cells. In the other, a low-power beam traces overlapping V-shaped paths, passing 46 times through a single vapor cell.
A Bose-Einstein condensate of europium atoms provides a new experimental platform for studying quantum spin interactions.
https://www.youtube.com/watch?v=WgLo4gmEraU
Lee Smolin is a theoretical physicist, co-inventor of loop quantum gravity, and a contributor of many interesting ideas to cosmology, quantum field theory, the foundations of quantum mechanics, theoretical biology, and the philosophy of science. He is the author of several books including one that critiques the state of physics and string theory called The Trouble with Physics, and his latest book, Einstein’s Unfinished Revolution: The Search for What Lies Beyond the Quantum.
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SPEAKING at the University of Cambridge in 1980, Stephen Hawking considered the possibility of a theory of everything that would unite general relativity and quantum mechanics – our two leading descriptions of reality – into one neat, all-encompassing equation. We would need some help, he reckoned, from computers. Then he made a provocative prediction about these machines’ growing abilities. “The end might not be in sight for theoretical physics,” said Hawking. “But it might be in sight for theoretical physicists.”
Artificial intelligence has achieved much since then, yet physicists have been slow to use it to search for new and deeper laws of nature. It isn’t that they fear for their jobs. Indeed, Hawking may have had his tongue firmly in his cheek. Rather, it is that the deep-learning algorithms behind AIs spit out answers that amount to a “what” rather than a “why”, which makes them about as useful for a theorist as saying the answer to the question of life, the universe and everything is 42.
The information security landscape is rapidly changing in response to quantum computing technology, which is capable of cracking modern encryption techniques in minutes, but a promising US government encryption algorithm for the post-quantum world was just cracked in less than an hour thanks to a decades-old math theorem.
In July 2022, the US National Institute of Standards and Technology (NIST) chose a set of encryption algorithms that it hoped would stand up to the encryption-cracking power of quantum computers and tasked researchers with probing them for vulnerabilities, offering a $50,000 prize for anyone who was able to break the encryption.
It is easier to form more substituted carbocations because of destabilisation in the parent substrate, rather than stabilisation in the reactive intermediate, new research shows.1
Many organic transformations involve carbocations as reactive intermediates. These are usually formed via a heterolytic C–X bond dissociation to give a carbocation C+ and an anion X-. Current understanding is that the bond dissociation energy decreases with increased methyl substitution because of the stabilising effect of the methyl groups, as well as relief due to steric repulsion: going from substrate to carbocation gives the substituents proportionally more room in a more substituted system. However, a team in the Netherlands, led by Matthias Bickelhaupt at VU Amsterdam, has investigated this from a different angle.
