/sci/ - Science & Math » Thread #10664765

7KiB, 200x207, images (5).jpg

View Same Google iqdb SauceNAO

/pg/ - physics general

Anonymous Thu 23 May 01:40:31 2019 No.10664765 View Reply Original Report

Quoted By: >>10664768 >>10664804 >>10664811 >>10665134

Dedicated to >>10664726
Talk physics.

Anonymous

Anonymous Thu 23 May 2019 01:43:13 No.10664768 Report

Quoted By:

>>10664765
I got a big peepee

Anonymous

Anonymous Thu 23 May 2019 01:47:25 No.10664774 Report

Quoted By: >>10664836 >>10664839

Is there any experimental basis for invoking Liénard-Weichert potentials in Classical Electrodynamics?

Anonymous

Anonymous Thu 23 May 2019 01:54:10 No.10664784 Report

Quoted By:

not science or math

Anonymous

View Same Google iqdb SauceNAO 41A47B69-3730-43F9-98FC-B6751432 (...).jpg, 88KiB, 1200x675

Anonymous Thu 23 May 2019 02:03:42 No.10664803 Report

Quoted By: >>10665054 >>10665397

>math general is anime fags
What are the physics boys like, hey? hm? Mmmmm?

Anonymous

View Same Google iqdb SauceNAO Winslow_Homer_-_A_Basket_of_Clams.jpg, 399KiB, 1280x1505

Anonymous Thu 23 May 2019 02:04:17 No.10664804 Report

Quoted By: >>10664808 >>10664912

>>10664765
I'm beginning to self-study thermal this summer with Kittel. Any tips or things to watch out for?

Anonymous

Anonymous Thu 23 May 2019 02:05:37 No.10664808 Report

Quoted By: >>10664830

>>10664804
>I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.
Newton

Good pic anon - should be the OP pic for Physics Generals from now on

Anyone use Anki for studying physics? If so, how?

Anonymous

View Same Google iqdb SauceNAO 150628174404-watches-that-change (...).png, 472KiB, 664x442

Anonymous Thu 23 May 2019 02:07:23 No.10664811 Report

Quoted By:

>>10664765
Huygens was a famous clock autist. How do I become a clock autist? Any books to read to unlock this mode?

Anonymous

Anonymous Thu 23 May 2019 02:18:25 No.10664830 Report

Quoted By: >>10664920

>>10664808
Isn’t that a flashcards tool? Why would someone do that

Anonymous

Anonymous Thu 23 May 2019 02:23:06 No.10664836 Report

Quoted By:

>>10664774
What? They are solutions to Maxwell's equations so obviously. But well you have radiation for direct evidence.

Anonymous

Anonymous Thu 23 May 2019 02:24:49 No.10664839 Report

Quoted By: >>10664917

>>10664774
we've never seen electrodynamic propagations travel instantly and are too capped at the speed of c

Anonymous

Anonymous Thu 23 May 2019 03:03:27 No.10664905 Report

Quoted By: >>10664932

How much differential geometry should you know to understand the mathematics of GR?

Anonymous

Anonymous Thu 23 May 2019 03:07:22 No.10664912 Report

Quoted By:

>>10664804
Consider pairing it with a slightly simpler, less terse text. I found Kittel both great for the breadth it covers as an undergrad text but also frustrating in how he presents/explains certain topics, especially definitions. I had my professor's lecture notes to go off of when I learned the stuff, but I hear Schroeder is decent.

Anonymous

Anonymous Thu 23 May 2019 03:10:30 No.10664917 Report

Quoted By: >>10664939

>>10664839
why would they be lower than c?
also gravitational effects propagate at infinite speed, no?

physics is very interesting

Anonymous

Anonymous Thu 23 May 2019 03:12:31 No.10664920 Report

Quoted By:

>>10664830
I’ve seen people talking about how they use it to learn math proofs...maybe it’s useful for derivations?

Anonymous

Anonymous Thu 23 May 2019 03:16:31 No.10664932 Report

Quoted By: >>10664943

>>10664905
What do you mean? Differential geometry *is* the mathematics of GR. Are you asking at what level of rigor? Depends on why you're studying GR. My biased opinion is that rigor = clarity. Skip around the first few lectures and problem sheets of these winter school lectures and see if you like the "mathematician's approach":
https://www.youtube.com/playlist?list=PLFeEvEPtX_0S6vxxiiNPrJbLu9aK1UVC_
https://www.youtube.com/playlist?list=PLFeEvEPtX_0RQ1ys-7VIsKlBWz7RX-FaL
(Regardless of you opinion on physics pedagogy, FS is a fantastic lecturer.)
In my opinion, a good physicist is able to learn and internalize the "mathematician's" mathematics and then translate it back into the "physicist's" mathematics. But I understand there are many who disagree with me.

Anonymous

Anonymous Thu 23 May 2019 03:19:09 No.10664939 Report

Quoted By: >>10664944

>>10664917
Gravity is also capped at c

Anonymous

Anonymous Thu 23 May 2019 03:21:23 No.10664943 Report

Quoted By:

>>10664932
I think I know what you mean by that. It’s a very respectable approach.

Anonymous

Anonymous Thu 23 May 2019 03:22:18 No.10664944 Report

Quoted By: >>10664946 >>10664980

>>10664939
Are you sure about that? Much of the universe would be escaping the influence of gravity of much of the rest of the universe due to expansion.

Anonymous

Anonymous Thu 23 May 2019 03:24:36 No.10664946 Report

Quoted By:

>>10664944
I don't think you understand what is propagating here

Anonymous

Anonymous Thu 23 May 2019 03:47:50 No.10664980 Report

Quoted By:

>>10664944
They time correlated the gravitational waves measured to infer where they were being generated (ie triangulated the source) in order to tell other telescopes where to point. Yes, gravitational waves are experimentally verified to obey the speed limit of c

Anonymous

View Same Google iqdb SauceNAO 1424286257023.png, 152KiB, 853x764

Anonymous Thu 23 May 2019 04:49:09 No.10665054 Report

Quoted By: >>10665062

>>10664803
good question.
i, myself, engage in empirical activities to better understand the world around me.

Anonymous

Anonymous Thu 23 May 2019 04:53:49 No.10665062 Report

Quoted By:

>>10665054
Lol

Anonymous

Anonymous Thu 23 May 2019 05:46:32 No.10665134 Report

Quoted By:

>>10664765
I'm an engayneer that wants to participate in theo. physics contests. Could any of you recommned study material?

Anonymous

Anonymous Thu 23 May 2019 05:46:59 No.10665135 Report

Quoted By:

What happens when I fail a class? Am I going to die?

Anonymous

Anonymous Thu 23 May 2019 06:00:42 No.10665164 Report

Quoted By: >>10665179 >>10666969

Why do we use displacement instead of path distance to to find velocity shouldn't the latter have more information my answer is that it has something to do with polygon law

Anonymous

Anonymous Thu 23 May 2019 06:07:46 No.10665179 Report

Quoted By: >>10665225

>>10665164
displacement is path distance

Anonymous

Anonymous Thu 23 May 2019 06:51:33 No.10665225 Report

Quoted By:

>>10665179
I mean path travelled

Anonymous

Anonymous Thu 23 May 2019 09:23:42 No.10665397 Report

Quoted By:

>>10664803
Chads, 90% of them are

Anonymous

View Same Google iqdb SauceNAO vp8.webm, 3MiB, 576x576

Anonymous Thu 23 May 2019 13:16:40 No.10665738 Report

Quoted By: >>10666266 >>10667384

I'm trying to create a reasonable model for diffusion across a membrane filled with ion channels to integrate into some FEM stuff.

The simplified versions of ion channels I'm working operate like a three-state state machine. There's the closed state where the diffusion coefficient is zero. This transitions to the open state with probability approaching one as the voltage around this channel reaches some threshold value. In the open state the diffusion coefficient is non-zero. Then there is a transition to the blocked state with probability approaching one as the time elapsed since opening approaches some threshold value. The closed state has zero diffusion coefficient and transitions to the closed state in a manner similar to the open-blocked transition.

I've written a little simulation with discrete channels (webm related, the surface is the voltage and the paths are the states of the ion channels with the ground state being closed, the next one up being open, and the next one after that being blocked) but is there some way to get a continuum model out of this? Like some kind of PDE that would give you the average diffusion coefficient at a point given the voltage?

Anonymous

Anonymous Thu 23 May 2019 13:26:42 No.10665756 Report

Quoted By:

How important is Anton Zeilinger in the world of physics?
Should every physics graduate have heard his name?

Anonymous

View Same Google iqdb SauceNAO physical_maths.png, 2MiB, 1202x910

Anonymous Thu 23 May 2019 17:46:54 No.10666230 Report

Quoted By: >>10666237

Threadly reminder to work with mathematicians.

Anonymous

Anonymous Thu 23 May 2019 17:52:45 No.10666237 Report

Quoted By: >>10666251

>>10666230
I’m scared of them

Anonymous

Anonymous Thu 23 May 2019 18:00:24 No.10666251 Report

Quoted By:

>>10666237
I’m scared of girls with good grades

Anonymous

Anonymous Thu 23 May 2019 18:09:57 No.10666266 Report

Quoted By: >>10666455

>>10665738
Do you have more webms?
I'm intrigued.

Anonymous

View Same Google iqdb SauceNAO average.png, 42KiB, 795x446

Anonymous Thu 23 May 2019 19:37:31 No.10666455 Report

Quoted By:

>>10666266
The webms are a bit of a pain to make so just a still image this time. This shows the average over a bunch of runs in a single location of where the state is open (open = 1, not open = 0).

Seems like the behavior could be modeled as a relatively simple filter with time lags and moving averages or something. Still need to check out spatial averaging and feedback stuff.

Anonymous

Anonymous Thu 23 May 2019 22:23:45 No.10666954 Report

Quoted By:

Bump

Anonymous

Anonymous Thu 23 May 2019 22:32:12 No.10666969 Report

Quoted By:

>>10665164
Velocity is directional. If you want the average velocity over a path, you can imagine integrating the instantaneous velocity vectors wrt time along the path (giving the overall displacement vector, rather than path length) and dividing by the time interval.

Anonymous

Anonymous Thu 23 May 2019 22:32:18 No.10666970 Report

Quoted By: >>10669831 >>10670718

How much work would self-teaching vibrations and waves be?

Anonymous

Anonymous Fri 24 May 2019 01:15:11 No.10667384 Report

Quoted By: >>10667660

>>10665738
Just to clarify

You have three states, C, O, B.

C -> O with a rate f(V), which approaches one as the voltage reaches some threshold.

O -> B with rate g(t) that approaches one as t -> infinity

And B -> O with rate h(t) with similar properties?

Just trying to formulate this in a language I'm familiar with (master equations). That said, it sounds like the average diffusion coefficient will depend on the history of voltages as well, which will have a timescale dependence on the timescales of g(t) and h(t).

Anonymous

View Same Google iqdb SauceNAO Screenshot from 2019-05-23 22-35 (...).png, 24KiB, 553x255

Anonymous Fri 24 May 2019 02:44:38 No.10667660 Report

Quoted By:

>>10667384
So these are the actual probabilities I was using for those figures. The $\Delta t$ being used is the elapsed time since entering the open/blocked state. So when it enters the open state it starts a timer and on each clock tick flips a coin weighted with the corresponding probability to see whether or not it should transition.

Anonymous

View Same Google iqdb SauceNAO Three-state-model-of-voltage-gat (...).jpg, 79KiB, 850x897

Anonymous Fri 24 May 2019 02:48:21 No.10667670 Report

Quoted By:

And just for reference this is what it is.

Basically trying to approximate what diffusion across a membrane with a large number of these looks like without having to simulate every single one.

Could probably get away with having just a few and averaging but wanted to see what my options really were.

Anonymous

Anonymous Fri 24 May 2019 17:08:30 No.10669247 Report

Quoted By:

BUMP

Anonymous

Anonymous Fri 24 May 2019 21:04:09 No.10669831 Report

Quoted By:

>>10666970
Pls

Anonymous

Anonymous Sat 25 May 2019 04:19:29 No.10670718 Report

Quoted By:

>>10666970
It depends, on what you mean by it. Just solving the wave eqauation could take you 2 weeks max. Learning about oscillatory phenomena, harder PDE theory and what not is hard.

Capcode	All Only User Posts Only Moderator Posts Only Admin Posts Only Developer Posts
Show Posts	All Only With Images Only Without Images
Deleted Posts	All Only Deleted Posts Only Non-Deleted Posts
Ghost Posts	All Only Ghost Posts Only Non-Ghost Posts
Post Type	All Only Sticky Threads Only Opening Posts Only Reply Posts
Results	All Grouped By Threads
Order	Latest Posts First Oldest Posts First

Your latest searches