Recent content by QuarkyMeson

What's costing you energy in that case is your negative Q. The product has a lower binding energy (more mass) than its reactants. The reaction is endothermic, you need to put energy into it to make it happen. That energy is coming from the kinetic energy before the fusion event. Whatever energy...

What I mean by this is, either you get a positive Q or negative Q and that determines if a given reaction is exothermic or endothermic. Energy input to make the reaction more favorable doesn't cost you anything, roughly. The Coulomb barrier is a conservative potential, mechanical energy is...

Maybe you can see if there are plans to limit the 2026 class of first year physics graduate students. :) https://www.aps.org/apsnews/2025/04/physics-departments-shrink-graduate-programs Here is another data point, this paints a better picture than I was getting this year, but this was...

Because you're fusing elements after the peak in binding energy your Q will be negative. You need to make up that budget with energy from another source, such as ##E_{input}## which, up to |Q| will then become part of the new nucleus rest mass.

It doesn't get released, it was there all along generally as kinetic energy. No, again, the graph only includes binding energy Q. ##E_{input}## doesn't go away in this case because energy is conserved. This activation energy is simply helping the reaction to occur, it doesn't get used up.

The energy released is simply the difference in masses between the products and reactants. ##Q = (m_1+m_2 - \sum M_{products})c^2##. The energy you put in, lets call it ##E_{input}## is still there, so the total energy you measure now is roughly ##Q+E_{input}## ignoring radiative losses after...

The graph represents what is on the axes- mass number against the average binding energy per nucleon. The average binding energy per nucleon represents how much energy you need to supply to unbind that nucleus completely. It's an intrinsic property of the nucleus in the ground state. It doesn't...

The units aren't correct. You're getting ##\frac{V^2}{Hz}##, which I think would be the noise voltage spectral density across the load and not the noise power spectral density delivered to the receiver.

https://www.statnews.com/2025/02/19/trump-funding-freeze-grad-student-postdoc-acceptances-paused-nih-research/ This is from last year: I think you're giving university admins more credit in subterfuge than they deserve. These students were ultimately admitted...

So basically a radio interferometer? That's pretty neat, I've always wanted to do something like this. So even when you stopped injecting noise into each you still had enough common noise to do a time sync? Do you know where the noise is coming from? Probably leakage? Theoretical Johnson noise...

The largest department I reached out to was MIT, and I haven’t heard back yet, which isn’t surprising. At this point in the year, professors are likely flooded with emails. Schools like the Ivies can afford to be selective and fill their programs without needing to respond to every inquiry or...

That's definitely fair and it's probably a good practice anyway. I just wanted to warn others that we live in strange times at the moment. From the departments I've spoken to, several that normally admit around 10 first-year PhD students are admitting 0 this cycle. This doesn't seem to be fully...

Given the current funding situation, you should contact potential departments or research groups before you apply and pay any application fees. Many programs are not taking new graduate students at all this cycle because of funding uncertainty, unless a specific advisor can show they already...

Longitudinal electric field isn't an observable, E is. (Save some electrostatic near field stuff when E is approx ##E_{\parallel}## and complete far field where E is approx ##E_{\perp}##). The question seems a bit ill framed in it's foundations, can a math equation violate causality? Sure. Can...

You would probably have better luck applying in Europe at the moment. Funding is a mess in the US at this point in time.