Monday, November 5, 2018

Physics cornucopia (physicopia?)

You know my eclectic file of intriguing news from the world of physics, into which I dip from time to time? Well, that file (metaphorically speaking, anyway) is bulging. Which gives us this week's topic.

You know all those tidy equations we learn in physics classes? They often deal with idealized situations, like friction-less planes. The real world tends to the chaotic.(*)
(*)  To physicists and mathematicians, "chaos" has a precise meaning: dynamic, generally nonlinear, systems that are extremely sensitive to initial conditions.

Or does it? See "Is nature really chaotic and fractal, or did we just imagine it?" A key quote:

The way we perceive reality is a function of how we slice and dice the physical world.

No matter how you slice it, the power of mathematics -- an invention of the human mind, surely --  to explain physical phenomena remains amazing. From the Department of Mathematically Examined Arcana, consider this: "History's most successful mathematical prediction." (Because, I'm pretty sure, regular readers here yearn to understand the origin of the precise magnetic field of a single electron.)

Within quantum theory, which is counter-intuitive from beginning to end, entanglement is one of the weirder aspects -- and that's saying something. QM has the equally annoying attribute of, time and again, being proven correct. That's not to say there's unanimity about what the math means, only that the math keeps being born out. And so it seems to have been once more, as "Ancient Starlight Just Helped Confirm the Reality of Quantum Entanglement." A key quote:

These results help settle a long standing debate in physics about whether entanglement is just an illusion that can actually be explained using principles of classical physics. These new results suggest that entanglement actually occurs because if it didn’t exist the universe would somehow have to have “known” 7.8 billion years ago that these MIT scientists would perform these experiments in 2018.

As that last quote suggests, the physical meaning of QM's math remains a hot topic of debate. But a recent experiment may have put the final nail in the coffin of one interpretation: the pilot-wave theory. See "Famous Experiment Dooms Alternative to Quantum Weirdness."

It seems like only yesterday (in fact, it was 2012) that CERN announced the discovery of the elusive Higgs boson: until then the remaining unconfirmed piece of the fabulously successful Standard Model of Particle Physics. In little more than a decade, if all goes well, we'll have lots of Higgs bosons to study. See "China unveils blueprint for huge underground 'Higgs factory' "

And (slightly) out of this world, let's turn to another bit of quantum weirdness. Certain particle types (for aficionados, particles with "integer spin") can be cooled and coaxed into an exotic phase of matter (distinct from the more familiar phases: solid, liquid, gas, and plasma). In a Bose-Einstein condensate, atoms are not subject to the famous Pauli Exclusion Principle, but rather are all in a common state. Like entanglements, BECs are famously fragile. Pesky things like random vibrations can destroy either, which makes space-based experiments with BECs so intriguing. And now such experiments are being done -- with more to come. See, "Rocket carries Bose–Einstein condensate into space."

Let's end this post with a (possible) answer to one of the Big Questions: why is anything here? Plenty of experiments support the theory that energy can spontaneously give rise to matter/antimatter pairs. Indeed, it is believed that the energy of the Big Bang gave rise, through just that mechanism, to matter and antimatter in the early universe. Here's the snag: when complementary particles (like, say, a proton and an anti-proton) meet, they mutually annihilate, turning back to energy. Why, then, is the observed universe composed overwhelmingly of matter? Why, in a universe billions of years old, haven't the primordial matter and antimatter managed to erase one another? Our very existence only seems possible if matter and antimatter in some way operate differently, or are otherwise out of balance.  So consider this: "Could Misbehaving Neutrinos Explain Why the Universe Exists?"

While you mull over all that, I'll get back to my writing :-)

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