Physics

Physicists have discovered a new phase of matter, dubbed "half ice, half fire," that could open the door to new advancements in fields such as quantum computing.

The new phase combines a number of "up" spins of electrons within an atom, which are highly ordered and referred to as cold cycles, with a number of "down" spins, which are highly disordered and referred to as hot cycles — lending the phase its nickname, "half ice, half fire."

"Half ice, half fire" is a significant discovery not only because of its novelty but also because it can produce sharp switching between phases at reasonable temperatures. It's the twin of the "half fire, half ice" state first observed by the same team at Brookhaven National Laboratory — physicists Weiguo Yin and Alexei Tsvelik, alongside their then intern, Christopher Roth — back in 2016.

These discoveries provide insight into some of the central questions in physics and the materials sciences, according to the team, as well as advance the ability to identify new states of matter with exotic properties and manipulate the transition between those states.

cross-posted from: https://discuss.tchncs.de/post/32182486

This deep dive by Sreenivasan & Schumacher explores the math, physics, and engineering challenges of turbulence—from Navier-Stokes equations to intermittency and beyond. A must-read for anyone fascinated by chaos, complexity, and the unsolved mysteries of fluid dynamics! 🌪️🌀 #Turbulence

Article link: https://www.annualreviews.org/content/journals/10.1146/annurev-conmatphys-031620-095842

Talk link: https://www.youtube.com/watch?v=fwVSBYh-KC4

For centuries, refrigeration tech has stayed the same — energy-hungry and reliant on harmful gases. Enter magnetocaloric cooling: a new solution claiming to be 30% more energy-efficient than current cooling systems. And it's scalable. From fridges to cooling buildings and server farms.

cross-posted from: https://lemmy.world/post/27047758

I read Feynman lectures on physics Volume 1 Chapter 37 for the 2nd time. It has the best explanation of the 2-slits experiment for me. 1 of the factors behind my <3 for physics is how amazing the universe is. The wave-particle duality is so amazing.

Chapters 1–36 aren't prequisites for Chapter 37. You can read 37 at once.

Global sea level rose faster than expected in 2024, mostly because of ocean water expanding as it warms, or thermal expansion. According to a NASA-led analysis, last year's rate of rise was 0.23 inches (0.59 centimeters) per year, compared to the expected rate of 0.17 inches (0.43 centimeters) per year.

"The rise we saw in 2024 was higher than we expected," said Josh Willis, a sea level researcher at NASA's Jet Propulsion Laboratory in Southern California. "Every year is a little bit different, but what's clear is that the ocean continues to rise, and the rate of rise is getting faster and faster."

In recent years, about two-thirds of sea level rise was from the addition of water from land into the ocean by melting ice sheets and glaciers. About a third came from thermal expansion of seawater. But in 2024, those contributions flipped, with two-thirds of sea level rise coming from thermal expansion.

cross-posted from: https://lemmy.world/post/26503399

Posting here hoping for a physics-based reply.

I viewed a vid re power versus torque in vehicles. My understanding is that power is torque multiplied by angular velocity. Given an amount of power, a high-torque vehicle won't go very fast. A very fast vehicle won't tow a very massive load.

I related it to my little knowledge re stick shift. Gear 1 is used to move a stopped vehicle or for low speeds. Does gear 1 mean max torque and lowest angular velocity? I imagine you need a high torque to overcome static friction. Does gear 2 mean a dip in torque and a rise in angular velocity? Does the max gear mean lowest torque and max angular velocity? When I was young, a driver said one can carefully switch from gear 1 to 2 then 2 to 3 (and so on) on a wide road with very few surrounding vehicles. He said this was the way to increase the velocity and a high gear generally meant more fuel-efficient.

Please correct me if any of the above is wrong.

I googled. Here's what I read –

" 'Revolutions per minute' is how many revolutions the engine itself is making per minute. The gear ratios then translate revolutions of the engine into revolutions of your tires (more or less). Lower gear means lower tire revolutions per engine revolution, but also the tires are easier to turn.

"So when the car is going slower, meaning it requires more force to accelerate, you want lower gears. As the car speeds up, you need less force to go faster or maintain that speed, so you switch to a higher gear, sacrificing power for more efficient use of your engine."

I didn't ask an llm to avoid hallucinations.

Superconducting magnets inside a fusion reactor will experience conditions that aren’t seen anywhere on Earth. Materials scientists Susie Speller and Chris Grovenor are trying to predict how long these components can last in this extreme environment

Scientists have made a leap forward in understanding the pattern and structure of turbulence — a natural phenomenon observed in fluids such as moving water, ocean currents, chemical reactions, blood flow, storm clouds, plumes of smoke and even the plasma of stars.

Measuring gravitational analogues of quantum phenomena could lead to high-precision measurement of gravitational forces, according to a theoretical proposal.

Here's a little physics riddle. It's really meant as a moment of self-reflection for physics teachers (I invite you to compare what answers you'd give within Relativity Theory).

We're in the context of Newtonian mechanics.

There are three small bodies. In the inertial coordinate system (t, x, y, z), we know the following about the three bodies (at a given instant of time):

• The first has mass 3 kg
• The second has velocity (1, 0, 0) m/s
• The third has momentum (2, 0, 0) kg⋅m/s

Now consider a new coordinate system (t', x', y', z') related to the first by the following transformation (a Galileian boost):

t' = t, x' = x - u⋅t, y' = y, z' = z with u = 1 m/s

Questions:

• What is the mass of the first body in the new coordinate system?
• What is the velocity of the second body in the new coordinate system?
• What is the momentum of the third body in the new coordinate system?

Can you give definite answers to these three questions, and motivate your answers with simple physical principles? Note that by "definite answer" I don't necessarily mean an answer with a definite numerical value.

cross-posted from: https://slrpnk.net/post/15007841

Eating gamma radiation for breakfast

Some fungal species appear to be able to use strong radiation as an energy source for growth. Tom Ireland explores the exciting potential of these understudied organisms

In the heart of World War II, as the Nazis took control of Copenhagen, a peculiar situation took place at the Institute of Theoretical Physics, led by physicist Niels Bohr. Two Nobel laureates Max von Laue and James Franck, fearing the confiscation of their gold Nobel Prize medals by the Nazis, had sent their medals to Bohr for safekeeping.

On the day the Nazis arrived in Copenhagen, Hungarian chemist Georgy de Hevesy, who was working in Bohr's lab, devised a plan to prevent the discovery of the medals. Initially considering burying the medals, they quickly dismissed the idea, fearing the thorough searches the Nazis would conduct. Instead, de Hevesy proposed a chemical solution — literally. Utilizing a mixture known as "aqua regia" (a blend of hydrochloric and nitric acids), he set about dissolving the gold medals. This concoction is one of the few substances capable of dissolving gold, a notably unreactive element. As the Nazis marched outside, de Hevesy dissolved the precious medals, reducing them to a colorless solution that eventually turned bright orange. The liquid containing the dissolved gold was then placed on a high shelf in the laboratory, where it remained unnoticed throughout the Nazi occupation​.

Post World War II, upon returning to the laboratory after V-E Day, de Hevesy found the beaker undisturbed on the shelf. The gold was recovered from the solution and returned to the Nobel Prize committee, who then reminted the medals and presented them back to Laue and Franck in a ceremony in 1952.

Source: Fermat’s Library via LinkedIn