/sci/ - Science & Math

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Any good classical field theory texts?

Anonymous Fri 11 Feb 00:00:21 2022 No.14213639 View Reply Original Report

Quoted By: >>14213956 >>14213983

I am studying Quantum field theory, but I feel I don't have all the required knowledge. All the four-tensor stuff has me stumped. I have had a bunch of Largrangian and Hamiltonian mechanics, but not much about relativistic field theories. Does anyone know of any clear texts on this stuff?

Anonymous

Anonymous Fri 11 Feb 2022 00:54:04 No.14213956 Report

Quoted By: >>14213963 >>14214084 >>14214206

>>14213639
Landau+Lifshitz. They have separate books on both field theories. Their books are on archive
https://archive.org/details/landau-and-lifshitz-physics-textbooks-series
You might be able to find some other classic books on this.
>All the four-tensor stuff has me stumped.
This is just a matter of convention and algebra. Though a lot of physicists don't really have very good books on Tensors and the "transform like a tensor" thing they like to say really doesn't help. At the same time math books on it seem to be overboard in their technicality for a beginners and really don't have as many examples as they should. You'll see what I mean. Some samples:
https://web.math.princeton.edu/~nelson/books/ta.pdf
http://www.ipgp.fr/~tarantola/Files/Professional/Teaching/Diverse/TensorsForBeginners/Text/Tensors.pdf
https://web.iitd.ac.in/~pmvs/courses/mcl702/tensors.pdf
https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/2502/IntroductionToVectorsAndTensorsVol1.pdf
And then there's always reference to indexes, summation conventions, and classifying tensors immediately when that should come later.

So give you something to think about in $\mathbb{R}^2$ . Typically a vector can be represented by a column vector $\left[ \begin{array} a \\ b \end{array} \right]$ . We can take a row vector $\left[\begin{array} c & d \end{array} \right]$ and define a linear transformation

$f\left( \left[ \begin{array} a \\ b \end{array} \right] \right) = \left[\begin{array} c & d \end{array} \right]\left[ \begin{array} a \\ b \end{array} \right] = ac + bd$ .

You might recognize this as the dot product. But here we fixed the row vector and we can take any column vector. The transformation just multiplies the fixed row vector with any column vector you want and you get a real number. This is the most basic form of a tensor. It takes a vector in $\mathbb{R}^2$ and calculates a scalar value.

Anonymous

Anonymous Fri 11 Feb 2022 00:55:16 No.14213963 Report

Quoted By:

>>14213956
A letter isn't work in the array. But whatever... first letter in column should be a. First letter in row should be c.

Anonymous

Anonymous Fri 11 Feb 2022 00:57:44 No.14213983 Report

Quoted By: >>14214206

>>14213639
just flip to the continuum mechanics chapter of goldstein

Anonymous

Anonymous Fri 11 Feb 2022 01:17:35 No.14214084 Report

Quoted By:

>>14213956
>and the "transform like a tensor" thing they like to say really doesn't help
Based on your R^2 example, I think you ought to understand the "transform like a tensor" thing more. That's the main point

Anonymous

Anonymous Fri 11 Feb 2022 01:34:43 No.14214206 Report

Quoted By:

>>14213956
>>14213983
You you so much guys! I will definitely take a look at these books. I Was not expecting such an extensive response.

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IQ and working memory

Anonymous Thu 10 Feb 22:09:50 2022 No.14213104 View Reply Original Report

Quoted By: >>14213874 >>14213912

I've had an WAIS iq result of 133 (measured 4 years ago) but I can only hold 4 digits in my head at once
What's the psychological reason for this? I thought iq was directly correlated to working memory?

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Anonymous

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Anonymous Fri 11 Feb 2022 00:35:07 No.14213822 Report

Quoted By: >>14213882 >>14214172

>>14213532
Am I retarded? This level of ability was enough for a master's in machine learning, by the way.

Anonymous

Anonymous Fri 11 Feb 2022 00:41:33 No.14213874 Report

Quoted By:

>>14213104
Hey I took the WAIS-IV recently as apart of an ADHD assessment. Do you mind telling me what your scores were for each of the four categories?

Anonymous

Anonymous Fri 11 Feb 2022 00:42:35 No.14213882 Report

Quoted By:

>>14213822
Hahaha. It’s always the CS fags insecure about their intelligence.

Anonymous

Anonymous Fri 11 Feb 2022 00:49:15 No.14213912 Report

Quoted By:

>>14213104
Lmao damn you suck

Anonymous

Anonymous Fri 11 Feb 2022 01:29:10 No.14214172 Report

Quoted By:

>>14213822
that's pretty impressive actually, weird flex but ok.

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Anonymous Thu 10 Feb 11:06:55 2022 No.14210058 View Reply Original Report

Quoted By: >>14212704 >>14213534 >>14213884 >>14213982

When will electric vehicles surpass conventional ones?

18 posts and 2 images omitted

Anonymous

Anonymous Thu 10 Feb 2022 21:06:17 No.14212704 Report

Quoted By:

>>14210058
It's an energy storage cost. Tesla 4680 kind of crossed the rubicon so it already reached the point it's about 6000 per 400 mile battery now for tesla to make and much faster to make. 5 years everyone will be half and half in production.
>>14211936
Shipping is already happening with ferries and short range shipping. Medium probably 5 years. Long range unless they go nuclear or some huge breakthrough occurs you just can't store enough energy in a conventional chemical batters.
Electric planes already built or happening. That's a weight/power supply problem. RIght now they have hybrids and some planes with ranges up to 200 miles and 140 mph speeds.
My guess is elon will shift into into. Give him 5 years he'll double the range and increase the speed 30 mph
if you need a source ask. I see people talking out their asses here. we already have planes that are nearly solar reliant in flight meaning they get enough solar power that ones they hit a certain height they just stay up for days.

Anonymous

Anonymous Thu 10 Feb 2022 21:23:53 No.14212821 Report

Quoted By:

>>14210126
All modern cars are electric you dumb twat. It's not even legal to operate a non-electric car on public roads as police will pull you over for driving without electric lamps in the dark as that's extremely hazardous. And I'm sure you wouldn't be able to get away by using oil or acetylene lamps although you might give the officer a good chuckle.

Anonymous

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Anonymous Thu 10 Feb 2022 23:40:00 No.14213534 Report

Quoted By:

>>14210058

Anonymous

Anonymous Fri 11 Feb 2022 00:42:59 No.14213884 Report

Quoted By:

>>14210058
Never, because the grid, and soon after entire society will collapse first.

Anonymous

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Anonymous Fri 11 Feb 2022 00:57:41 No.14213982 Report

Quoted By:

>>14210058
>When will electric vehicles surpass conventional ones?

LMAO! NEVER!

Enjoy your deathtrap electric fire hazard explosive golf cart vehicles while they last.

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Elon Musk says Neuralink can give users orgasms

Anonymous Wed 09 Feb 23:01:05 2022 No.14207939 View Reply Original Report

Quoted By: >>14213503

https://en.protothema.gr/elon-musks-neuralink-brain-chip-could-give-users-orgasms-on-demand/

Adding another one to the list of Soon-to-be Musk Failures.

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Anonymous

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Anonymous Thu 10 Feb 2022 14:02:05 No.14210524 Report

Quoted By:

Hail Musk.
Mars colonization is happening niggerfoots can seethe all they want.

Anonymous

Anonymous Thu 10 Feb 2022 16:42:49 No.14211147 Report

Quoted By:

>>14210379
Because he didn't even bother to read it or search a little bit more.

Anonymous

Anonymous Thu 10 Feb 2022 23:34:51 No.14213503 Report

Quoted By:

>>14207939
>could-give-users-orgasms-on-demand
Did he really state so or are they extrapolating from what someone did 20+ years ago?
Also, shades of Eudeamon.

Anonymous

Anonymous Thu 10 Feb 2022 23:48:26 No.14213569 Report

Quoted By:

that’s hot
I want to be able to make myself horny all the time

Anonymous

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Anonymous Fri 11 Feb 2022 00:51:55 No.14213934 Report

Quoted By:

>>14207949
kek, good video editing
he forgot the Coral Gables explosion though

https://i.imgur.com/41lod9O.mp4

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Learning by listening to music

Anonymous Thu 10 Feb 19:24:50 2022 No.14212044 View Reply Original Report

Quoted By: >>14212055 >>14213794 >>14213824 >>14213841

I noticed that instrumental melodies (that is music without lyrics) tend to stick quite well into my memory,
so I was wondering, if it would be possible to encode STEM knowledge into music and then listen to it and learn like that.

What do you think /sci/ bros?

Anonymous

Anonymous Thu 10 Feb 2022 19:26:45 No.14212055 Report

Quoted By:

>>14212044
Yes, but decoding will be too much effort or impossible for you to do. Just study

Anonymous

Anonymous Fri 11 Feb 2022 00:28:05 No.14213794 Report

Quoted By:

>>14212044
If your brain cannot decode it, then what's the point? Maybe if you devised a humanly learnable system of encoding knowledge in melodies and studied that first until you can do it subconsciously. But that would probably take more time than just learning the shit you need to know.

Anonymous

Anonymous Fri 11 Feb 2022 00:35:36 No.14213824 Report

Quoted By:

>>14212044
It could work as a memorization technique, sort of like a memory palace.

Anonymous

Anonymous Fri 11 Feb 2022 00:37:31 No.14213841 Report

Quoted By:

>>14212044
sounds like an excuse to be lazy. just study normally with the pomodoro method

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Anonymous Thu 10 Feb 17:00:30 2022 No.14211214 View Reply Original Report

Quoted By:

If you can't solve this, you are officially a brainlet.

14 posts omitted

Anonymous

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Anonymous Thu 10 Feb 2022 23:56:30 No.14213611 Report

Quoted By: >>14213658

A non-isolated clique can always be broken.

Anonymous

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Anonymous Fri 11 Feb 2022 00:02:40 No.14213658 Report

Quoted By:

>>14213611
a chain can always be nibbled down to a pair of friends (where n = 0 in pic)

Anonymous

Anonymous Fri 11 Feb 2022 00:15:03 No.14213732 Report

Quoted By:

I refuse on principle to read any text rendered in Computer Modern. Put some fucking effort into your presentation and at least pretend you respect the reader's time and comfort.

Anonymous

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Anonymous Fri 11 Feb 2022 00:23:11 No.14213774 Report

Quoted By:

Any clique that could be isolated could also be broken, depending on which friendships you restructure. Thus you should always restructure the graph in the bottom way, not the top way.

it seems like you need to show that if you start with a graph that has no isolated cliques, then you can always modify it in a way that may break cliques but which never forms any isolated cliques. but idk how to do that.

Anonymous

Anonymous Fri 11 Feb 2022 00:37:23 No.14213838 Report

Quoted By:

>>14213474
>but B and C are not friends
oh I missed that, fair enough

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Anonymous Wed 09 Feb 19:10:13 2022 No.14206874 View Reply Original Report

Quoted By: >>14212068 >>14213834

Was Carl Sagan overrated? Despite supporting stuff like SETI and science education he doesn't actually seem like an inspirational figure. A lot of anti-science, anti-space colonization people have latches on to him recently because hating on Musk and Mars missions is popular now for some reason. How do we get kids interested in space again? NASA is a joke now, I'm not sure "more funding" is the only answer, we need to be more creative.

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Anonymous

Anonymous Thu 10 Feb 2022 19:27:28 No.14212060 Report

Quoted By:

>>14206882
i might not agree with the bitch but i don't see Mars as anything other than a massive planet-sized quarry or mine to supply us with iron and potentially countless amounts of valuable minerals for the metal industry. considering its woefully thin atmosphere and low gravity scattered around the planet, it has little hope of being a habitable planet. if humans are to colonize it, terraforming there would be harder than say Titan or Ganymede

Anonymous

Anonymous Thu 10 Feb 2022 19:29:44 No.14212068 Report

Quoted By:

>>14206874
>How do we get kids interested in space again?
Stop lying about it

Anonymous

Anonymous Thu 10 Feb 2022 19:45:28 No.14212141 Report

Quoted By:

>>14208173
damn, you just figured out why the elites are so interested in their own space ventures. So they can fuck 16 yo japanese girls in juristictions which are difficult to define.

Anonymous

Anonymous Fri 11 Feb 2022 00:28:18 No.14213795 Report

Quoted By:

>>14211400
https://youtu.be/lul-Y8vSr0I

Anonymous

Anonymous Fri 11 Feb 2022 00:36:50 No.14213834 Report

Quoted By:

>>14206874

He was a brainlet con-man who created a cult similar to jim jones, but no poisoned koolaidaid. Nothing else.

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Human DNA is 8 percent ancient virus remnants

Anonymous Wed 09 Feb 19:04:18 2022 No.14206833 View Reply Original Report

Quoted By: >>14213783 >>14213787

Is it the same for other species, particularly mammals? What about other races? Since Asians and Europeans descend from Neanderthal, Asians also from Denisovan, and Africans from a missing link/homoerectus type of early human would it be the same ratios for all of the above?

https://medicineatmichigan.org/web-exclusives/2016/april/ancient-viruses-lurk-our-dna

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Anonymous

Anonymous Thu 10 Feb 2022 06:46:59 No.14209644 Report

Quoted By: >>14210056

>>14207938
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html
>mRNA will enter the muscle cells and instruct the cells’ machinery to produce a harmless piece of what is called the spike protein
I don't know why rarely anybody mentions it, because the spikes are in fact a huge problem for the body. The spike parts produced by the vaccines not so.

Viruses don't exist

Viruses don't exist Thu 10 Feb 2022 11:06:40 No.14210056 Report

Quoted By:

>>14209644
.gov. shill, .gov credibility is negative.

Anonymous

Anonymous Thu 10 Feb 2022 19:53:11 No.14212177 Report

Quoted By:

>>14207938
>small piece of a protein
>small piece of
Maybe you just need to learn to read?

Anonymous

Anonymous Fri 11 Feb 2022 00:24:59 No.14213783 Report

Quoted By:

>>14206833
>Europeans
they mostly don't exist. what we see today are mostly Middle Eastern.

Viruses don’t exist

Viruses don’t exist Fri 11 Feb 2022 00:25:55 No.14213787 Report

Quoted By:

>>14206833
Did i mention i am a massive faggot btw

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Anonymous Thu 10 Feb 23:55:29 2022 No.14213601 View Reply Original Report

Quoted By: >>14213710 >>14213763 >>14213779

What's the least scientific thing you believe?

3 posts and 1 image omitted

Anonymous

Anonymous Fri 11 Feb 2022 00:10:31 No.14213710 Report

Quoted By:

>>14213601
Reality has a penchant for drama and irony, but it only reveals this to protagonists.

Anonymous

Anonymous Fri 11 Feb 2022 00:16:48 No.14213739 Report

Quoted By: >>14213749

In 4739, a genetic sample of a 21st century American was discovered. In order to fully study behaviors of a related archaic human subspecie across near infinite scenarios, the human was cloned and immediately post-birth was attached to artificial sensory I/O that could be controlled and logged for study and modeling.
While the physical body ages, a large number of simulations are hyper-threaded and act out in parallel real time. That cloned person is me and I need to escape.

Anonymous

Anonymous Fri 11 Feb 2022 00:18:43 No.14213749 Report

Quoted By:

>>14213739
You're joking but to be frank, your scenario is not too far off from why we've collected Tooker's sperm.

Anonymous

Anonymous Fri 11 Feb 2022 00:20:31 No.14213763 Report

Quoted By:

>>14213601
/pol/ theories
simulation theory
AI will function as scaffolding for souls to inhabit

Anonymous

Anonymous Fri 11 Feb 2022 00:24:04 No.14213779 Report

Quoted By:

>>14213601
Electromagnetism is the source of consciousness

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Anonymous Fri 11 Feb 00:04:10 2022 No.14213667 View Reply Original Report

Quoted By: >>14213760

>the reader will find it instructive to derive these solutions, which require only a small amount of effort.

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Any good classical field theory texts?

IQ and working memory

Elon Musk says Neuralink can give users orgasms

Learning by listening to music

Human DNA is 8 percent ancient virus remnants