Theoretical Definition and 999 Threads

I want to learn how to calculate maximum theoretical specific energy of various battery combinations consisting of a single metal and single oxidant, like for example Sodium - Sulfur, Potassium - Sulfur or even crazy stuff like Rubiddium - Iodine. I asked this question on stackexchange but I...

I recently came across a book called advanced theoretical physics -nick lucid. chap6 covers tensors and chap 7&8 cover SR&GR. I have studied a bit of SR before but never GR. At this point in life I don't want to read huge books on the subject. this book covers relativity entirely in three...

Basically, I'm wondering if there have been any attempts to calculate/model what the radius of the sun should be based on gravitational, thermal, and electromagnetic pressures. If there has, where can I find the calculation/model, and how closely does it match the actual radius of the sun...

An interesting essay:

Hello, I have several questions around the application process as well as the organization. 1. Are you aware of any reference website centralizing PhD offers by countries? 2.When it comes to the organization/management/ supervision of a PhD program, I wonder if there are differences by...

What are they employed to do most of the time? I read that Albert Einstein was working at a patent office when he came up with his theories. So do theoretical physicists work on stuff they are interested in their free time as opposed to when they are at work?

A year ago, I asked a question about two journals, both of which were predatory ( https://www.physicsforums.com/threads/are-open-access-journals-legit-for-my-cv.990744/ ). Thanks to the overwhelming advice I have received, I did NOT publish in either of those journals. Right now I am asking a...

I am currently learning to code by auditing Harvard's CS50 course on edx. I am mainly interested in pursuing a theoretical physics major in the future. What I would like to know which scientific computing software/language (as in OCTAVE, SCILAB, FORTRAN, JULIA, etc ) can I learn alongside which...

-

Hi everyone, I was quite excellent at STEM subjects at school, but struggled (bad) at art classes. Here's why: At grade 9 of middle school, one of the job (assignment) that I had to perform in weeks was singing Amayadori by Mayumi Itsuwa. I and other students were given photocopies of music...

I am recreationally self studying physics and math with the ultimate goal of understanding theoretical/mathematical framework of classical mechanics, general relativity, and quantum mechanics (in addition to the actual physics). The question I have is how deep in the realm of pure math does one...

After graduating with 2-years Masters in TP, I wish to return to academia by undertaking a PhD in theoretical physics and I have A LOT of questions since I am aware that it is a, extremely competitive area especially when you were out of the game for a while, about 5 years for me… What are the...

It looks as if ultra-light and super-heavy have become less likely. https://www.sciencedirect.com/science/article/pii/S0370269321000083

I have a B.S in Mathematics, but wish to pursue Theoretical Physics. I still have a great deal of undergraduate Physics coursework to take before I can apply to graduate programs. My question has to do with the Mathematics that is crucial in order to do Theoretical Physics. Is the mathematics...

Out of sheer curiosity, would a polymer of the following structure be theoretically possible? Imagine that the "N-methyl" groups are just the bounds of what is shown, and not actual carbon-containing substituents... It doesn't seem to break any elementary bonding rules. However, the C-C bond...

Summary:: Theoretical reaction force due to ball traveling in a semi-circle circum Hi, Can anyone please help me with the following question: Setup... 1 x length of pipe bent 180 degrees with an inner diameter of 22mm, it's radius is 2mtrs, the mass of this object is 100kg. Total length of...

I would like to understand, for a science fiction book idea, if there is a possibility to create a theoretical energy plant that would circle the sun and tap into it's core and drain energy from the core (to use for human needs) and in the process would "drain" the sun or "shorten" it's life...

If the Summary is not clear, the following is an example translated from: https://telecombloger.ru/7335 '... air conditioning systems. For example, the efficiency of a compressor is about 85%. The remaining 15% is spent on friction, oil movement, overflows, heating, etc. The efficiency of the...

A rough explanation of my attempts: I set the coordinate axis in a way that x is the horizontal base and y is perpendicular. But I guess it is a 3d problem, so I struggle finding the right position of the coordinate system. Then, my next step was applying 2nd NL for every axis. So far I have...

Hello everybody, I am an undergraduate student studying computer science and I love it, especially Artificial Intelligence. I'm a curious person, so there are a lot of things that I find intriguing. But I sometimes wonder if a physics career would be more interesting, not because I don't like...

I had read somewhere that this value is 130 °F at sea level (and thus the 134 °F one at Death Valley back in 1913 is suspect). Is there some paper that explains how this figure was derived?

Conversion: 1.0 t = 1.0x10^6 g impure Si Conversion: 2.33 t = 2.33x10^6 g SiCl4 Atomic Mass Si = 28.085 g/mol Atomic Mass Cl2 = (2 x 35.453) = 70.906 g/mol Mass SiCl4 = 28.085 + (4x35.453) = 169.897 g/molI got all this part down, however, I'm not quite sure where I am supposed to go from there...

This might be total nonsense, but the thought popped into my head while I was trying to get to sleep, so I thought I see if I could find any advanced help with the following hypothetical: If light were instantaneous, how far from Earth would the sun have to be to cause a quark orbiting in place...

There are a few different textbooks out there on differential geometry geared towards physics applications and also theoretical physics books which use a geometric approach. Yet they use different approaches sometimes. For example kip thrones book “modern classical physics” uses a tensor...

Modern batteries use double-sided anode and cathodes for greater energy density. Series wiring of batteries is typically accomplished by connecting the anode of one cell to the cathode of another. However, can series be accomplished by stacking double-sided anode and cathode alternatingly with...

I consider the band-pass filter of the following configuration (the ##u_m## is a voltage controlled voltage source): The transfer function is $$K_1(p)=\hat{U}_o(p) = \frac{p}{RC(p+1/RC)^2} = \frac{\omega_c p}{(p+\omega_c)^2}, \quad \omega_c=\frac{1}{RC}.\qquad (1)$$ Now I connect ##n## such...

Long times have been that I've decided changing my job from engineering to theoretical physics. Because I don't want to learn the rules that have been discovered by any scientists and make a situation about getting it real :]. I want to learn how the rules of nature is being discovered and what...

On Page 406 of Nolting Theoretical Physics 1 he has the following notation for the Jacobian determinant $$\frac{\partial( x_{1}, x_{2})}{\partial (y_{1}, y_{2})} = \begin{vmatrix} \left (\frac{\partial x_{1}}{\partial y_{1}} \right )_{y_{2}}& \left ( \frac{\partial x_{1}}{\partial y_{2}}...

Hello, this is my first post. So sorry for the long read in advance. I will graduate from Part II mathematical tripos this year, and I'm currently having a hard time deciding where to go for my Master: For now, I'm definite that I want to do theoretical physics PhD (gravity, cosmology, or...

Hi all, I'm going to graduate this May with a degree in Electrical Engineering. While I've done pretty well, my passion was never in EE and I'd like to aim for graduate school in Computational Neuroscience. When I look at the background and methodology employed by many favorite (current)...

Hello all, I'm doing a Master's Degree in Theoretical Astrophysics and now I need to decide in which topic I will do my final project and I wanted to ask you what would be the best option. I would like to do something that would make me have some future in the investigational path I choose...

If I haven't heard back as of yet, does that mean that I haven't been shortlisted? When are interviews usually held and when do people usually find out? My feeling is that if I haven't heard back from the universities as of yet, I haven't been shortlisted but I'm hoping someone more...

I was often told that If you want to pursue something pure and abstract like theoretical physics and pure maths you have to give up the materialism , say good bye to your dream of living a big house , swimming pool and a yatch. there is no weath in these fields. And people who work in these...

Dear everyone, My younger brother who is 15 years old and me, both live in the UK. He is determined to become a theoretical physicist like Zeldovich or Ginzburg. We have an opportunity to send him to a US high school because it is the best place to become and be a physicist. Could you please...

When I was studying the bachelor in physics, I was happy and got good marks (not the best, but good). I always liked the more theoretical and mathematical subjects. Then I did a masters in Theoretical Physics in Spain. At the beginning I was happy: all subjects were hard but interesting. I spent...

Are there expositions of why various theoretical attempts by prominent physicists failed? - or is it mostly the case that they told people they were making such attempts and never published anything? For example in the thread...

I just finished my sophomore year of a 4-year undergrad in Physics, what relevant courses should I take to pursue my career in theoretical physics research? Advanced grad courses are to be recommended too, thanks.

Dear users, The situation I have encountered is a simple statistical comparison of the experimental data, which accepted as correct, with the results obtained via six theoretical models. In the experimental data, there exist y values corresponding to x values and also the measurement errors of...

Given: V_1 = 10 L, V_2 = 22 L Not sure what I need to do here. We are told to ignore heat transfer, and the problem suggests that this is not a steady-state problem. The gage pressure is given, so I think that means we need to calculate for the absolute pressure, which would be 997 kPa. Cp and...

In respect to the above question, I also have a follow up question. Is progress in Theoretical Physics somewhat slow currently as compared to Experimental Physics?

[Moderator's note: New thread spun off from previous discussion due to more advanced subject matter being discussed.] There is, in fact, a quite good argument that Hawking radiation cannot be derived by semiclassical theory. It is the comparison with the scenario where the collapse stops some...

I'd like to start by saying I don't know if this is the right place to post this, but I feel this community will be able to help me more than any other regarding my issue. I'm an Irish student currently studying undergrad theoretical physics in Trinity College Dublin. Growing up, I was somewhat...

Hello! All of my undergraduate research so far was in experimental fields, mainly because most of my professors are doing that at the university. The few ones who are doing something more theoretical are mainly working on numerical simulations. I have always been fascinated about theoretical...

I have come across some online references to Generic Objects of Dark Energy (GEODEs). They are briefly described in this Wikipedia article: https://en.wikipedia.org/wiki/Generic_object_of_dark_energy The only reference from that article that I have been able to find online is this paper...

I am interested to understand the current theoretical status of Landauer's Principle and related ideas. I am looking for key papers and results in the subject. I will highlight one key paper. An improved Landauer principle with finite-size corrections Abstract: Landauerʼs principle relates...

Hi all, I am currently involved in a theoretical physics project and would like some advice. One of the main takeaways I hope to (well,) take away is the capacity to make simple physical/mathematical statements that are valid, which seems to be an important part of theoretical physics. How do...

Hello everyone! Apologies if this question has been asked and answered before, please feel free to direct me to that post and delete this one, if needed and if it has been asked before and this post is, hence, redundant. I looked up some of the earlier posts such as...

I'm starting at Durham on the 29th of September and I need to get my module choices sorted. I have the choice between 40 credits of maths modules designed for scientists, and 40 credits of maths modules done by regular maths students. They say that you should only do the regular maths modules if...

I am a masters student studying motion analysis in human running. I need to find the angle of the parable tangent derived from the theoretical arc traced by a foot during a step and the ground (see attached). The arc comprises of a persons step height and step length and I need to find the...

This may be a stupid question, but here is what I am asking. Using a very simple circuit, say 120v AC water heating element rated at 1000 watts meaning 120v AC hot leg on 1 terminal and a neutral on the other terminal. That would give 8.3 amps of current, meaning the resistance would be 14.4...