Given that these correlations cannot be mere coincidence, and that information cannot travel faster than light, how do these two electrons "know" about each other and maintain their correlation?

I’m enrolled in a research course this term, and my work is on the dynamics of Bloch electron in crystals. It’s mostly semiclassical dynamics, and there’s a lot of work involving Berry curvature.

Marder’s Condensed Matter Physics is one of the assigned books I’ve been given, but because it’s a graduate level book and I don’t have sufficient completed coursework in quantum mechanics, I can’t finish the whole thing myself.

Regardless, I want to get an intuitive understanding of what crystal momentum and Berry curvature are. What is reciprocal space? Is Berry curvature a property of the reciprocal space? What are the closest analogues in classical particle dynamics?

I have been studying thermodynamics in my high school and have come to know recently that the Expansion of the universe is an irreversible adiabatic process that its entropy will always increase. But how is that and where is even the energy source that is provided as in temperature Internal energy in general classical thermodynamics processes?

hi, I’m having trouble finding ideas for a high school physics project (it’s a group project) our teacher is very picky and doesn‘t like project topics that would be easier and more efficient for us as students (out of the box ideas if you will)

topics can be anything related to physics but we don’t have a physics lab or any physics equipment so any experiment that involves equipment we the student have to provide it ourselves

topics that we have in our curriculum to give you an idea on what we’re learning:

1/ unit on gravity (basic intro to astrophysics think kepler’s law, cavendish‘s experiment, newton‘s law of universal gravitation, ect)

2/ unit on rotational motion (angular velocity, angular acceleration,torque,ect)

3/ momentum and its conservation (impulse and momentum)

4/ work energy and simple machines

5/ energy and its conservation

6/ thermal energy

I asked this in a scale-visualization post in another subreddit, figured I should ask actual physicists.

Each nucleon is three quarks bound tightly together but the shell model has, well, shells. I can't quite wrap my head around how that works with the very short-distance forces going on in the nucleus.

Hi all,

(EDIT: It unfortunately appears that this paper has since been debunked, as environmental artifacts were not properly accounted for. Thank you to everyone involved in the discussion!)

I came across an interesting paper by P.A. Sturrock, E. Fischbach, et al entitled "The case for a solar influence on certain nuclear decay rates".

As we were all taught, nuclear decay is stated to occur at a fixed (probabilistic) rate. However, this paper and a few others by these same authors find significant (~1%) variation in the measured rate of decay based on the earth-sun distance, and also solar activity, leading to them directly suggesting that neutrinos may influence the rate of nuclear decay. As far as I can tell, these papers seem quite conclusive that decay rates are not absolutely constant, but I had never before heard even a hint of discussion regarding this.

As I understand it, their model suggests that the neutrinos may impart kinetic rotations on the nuclei, and thereby modulate the rate of decay. However, I was wondering why this has never been linked with inverse beta decay (a neutrino being absorbed by a nuclei, and instigating a beta decay). It seems like a fairly straightforward connection, but I couldn't find any work suggesting the concept.

Interestingly, my thought process on this was almost the reverse order of the researchers, whereby I came upon the topic by thinking about if/how solar neutrinos could theoretically impact nuclear decay rates, and hypothesised that you may see a change in decay rates (due to IBD) based on Earths' orbital radius. Then my research came across that paper seemingly affirming the pattern.

Does anyone here have more familiarity with either of these concepts, and could point me towards more discussion/research? This has sent me down a real rabbit-hole, but my physics is a little rusty to dig too much further myself. I would also expect a similar effect to occur around nuclear reactors (massive anti-neutrino sources), but I am finding very sparse and mixed results.

Thanks all :)

I'm reading 'Red Mars' by Kim Stanley Robinson, and came across the line: "Total column mass about 10^-3 grams per cm^-2." (The actual text is more elegant with properly written exponents)

It looks to me that this unit is wrong, using "per" and also using the negative exponent is doing the same thing. Wouldn't you use one or the other?

I am looking at AP placement on my ceiling and trying to determine if it can reach a IoT device in my attic. I am looking at Ubiquiti U7 Pro XGS and found the AP spectrum pattern for this device.

From what I can gather, I should have pretty good coverage I place my wireless plug 9' horizontal and 3' vertical from the AP. The device uses the 2.4GHz band.

https://imgur.com/a/hOrySN4

Anyone good at reading spectrum maps? From what I can gather through google, I should have pretty good coverage if my IoT device is 9' horizontal and 3' vertical from the AP. At 9' out and 3' up, the device sits at a diagonal angle of approx 72 degrees off the center vertical axis. Near the 60° to 75° mark, the color is a solid, vibrant orange/red.

Just trying to confirm I am reading this correctly, as I am not an RF engineer and not really sure what the charts describe.

does the current in plasma globes prefer your skin over air because skin has less resistance?

This came up as I was explaining to my 12 yo about the why you land at the same spot when you jump in a train. If somebody can explain this in a way to explain the underlying concepts that will be very helpful.

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Olá a todos! Tenho 14 anos e estou começando a estudar física nuclear por conta própria. Tenho interesse em compreender a física fundamental das interações entre nêutrons.

Entendo que dois nêutrons livres não formam um estado ligado estável nas condições conhecidas, e gostaria de aprender mais sobre esse assunto.

Tenho três perguntas:

1. Quais são as principais razões físicas pelas quais dois nêutrons livres não formam um estado ligado estável?

2. Quais modelos matemáticos ou simulações computacionais vocês recomendam para estudar as interações entre nêutrons e o dineutron hipotético?

3. Quais livros, artigos científicos ou materiais educativos confiáveis vocês recomendam para alguém que está começando a estudar esse tema?

Meu interesse é compreender a física teórica e explorar cálculos e simulações educativas.

Agradeço por qualquer orientação ou recomendação de material de estudo!

The power output from a wind turbine is proportional to the cube of the wind speed. This can easily be shown using dimensional analysis.

Similarly, the radius of the shock wave from a nuclear explosion is proportional to the 2/5 power of the time since detonation, as shown independently by John Von Neumann and GI Taylor during WWII in classified documents.

What other scaling laws can be found using dimensional analysis

Is it energy or force?

There appears to be sort of three or four versions or notions of “acceleration” I can think of, and I want to ask a bit about them.

There is the type of acceleration where something like thrusters are used to increase velocity for one object relative to another object.

There is a notion of (effectively) “acceleration” where if I go forward with constant velocity, measuring time with my clock, away from some planet let’s say and another ship passes under me going towards the planet, and the ship syncs its clock with mine as it passes, effectively “information has accelerated relative to earth”/the information has a change in reference frame.

There is the concept of gravitational assist that is also considered acceleration, where an object can increase/change velocity relative to some other object via a gravitational assist.

(I suppose you could also do the same with magnets and have “magnetic assist” of a magnet, where the magnet wouldn’t feel itself accelerating, or?)

First of all, is it the case that it is only the first version that is considered proper acceleration or are all considered/called proper acceleration?

A thing these scenarios have in common is a change in reference frame. They will age less relative to an object that does not engage in any of this if they start off together and then meet up.

What do these scenarios have in common that leads to a change in reference frame contra objects that do not engage in these scenarios and only “experience” the coordinate acceleration (fourth notion of “acceleration”) relative to objects that engaged in these processes (even though there of course is no universally agreed upon coordinates in space and velocities and distances always have to be defined relative to other objects)? Can that be explained in more detail or is it more accepted as a rule, that:

“If any object/information engages in one of these three scenarios of using something like thrusters, clock syncing or gravity assist, then they have a change in reference frame and objects that do not engage in any of this will not change reference frame (in a universe with no ‘official coordinates’)” ?

First question is if such dimensions exist? Second question, if it doesn’t exist, is there any practical applications for calculating such dimensions? I remember in my math classes we had to integrate a 3D shape before, practically making a 4D shape, so is something similar for time?