Not to be confused with algebra over a field, which is a particular algebraic structure studied within algebra.
Condensed matter physics is one of the best examples of emergence. We start with a bunch of small elements which we understand fully at the required level (atoms, electrons, quantum mechanics) but then there are complex properties that show up when we put a bunch of them together.
Includes fun things like:
As of 2020, this is the other "fundamental branch of physics" besides to particle physics/nuclear physics.
Condensed matter is basically chemistry but without reactions: you study a fixed state of matter, not a reaction in which compositions change with time.
Just like in chemistry, you end up getting some very well defined substance properties due to the incredibly large number of atoms.
Just like chemistry, the ultimate goal is to do de-novo computational chemistry to predict those properties.
And just like chemistry, what we can actually is actually very limited in part due to the exponential nature of quantum mechanics.
Also since chemistry involves reactions, chemistry puts a huge focus on liquids and solutions, which is the simplest state of matter to do reactions in.
Condensed matter however can put a lot more emphasis on solids than chemistry, notably because solids are what we generally want in end products, no one likes stuff leaking right?
One thing condensed matter is particularly obsessed with is the fascinating phenomena of phase transition.
What Is Condensed matter physics? by Erica Calman
. Source. Cute. Overview of the main fields of physics research. Quick mention of his field, quantum wells, but not enough details. Connect two computers directly without a router with an Ethernet cable Updated 2025-04-24 +Created 1970-01-01
For IP-level communication, askubuntu.com/questions/22835/how-to-network-two-ubuntu-computers-using-ethernet-without-a-router/116680#116680 just worked between P51 and P14s both on Ubuntu 23.10 connected with a regular Cat 5e cable.
On both machines, first we found the Ethernet cable interface name with the which outputs on the P41s:so the interface was
ip CLI tool:ip a1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp1s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether fc:5c:ee:24:fb:b4 brd ff:ff:ff:ff:ff:ff
3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 04:7b:cb:cc:1b:10 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.123/24 brd 192.168.1.255 scope global dynamic noprefixroute wlp2s0
valid_lft 61284sec preferred_lft 61284sec
inet6 fe80::3597:15d8:74ff:e112/64 scope link noprefixroute
valid_lft forever preferred_lft foreverenp1s0f0, because wlp is wireless and lo is localhost.So on the P14s we assign an IP of 10.0.0.10 to the P51:
sudo ip address add 10.0.0.10/24 dev enp1s0f0Then on the P51 analogously, giving IP of 10.0.0.20 to the P14s:
sudo ip address add 10.0.0.20/24 dev enp0s31f6And after that, P14s can:and P51 can:
ping 10.0.0.10ping 10.0.0.20As mentioned at Human Compatible by Stuart J. Russell (2019), game theory can be seen as the part of artificial intelligence that deas with scenarios where multiple intelligent agents are involved.
Applications of power, we have to remember it is there to notice how awesome it is!
- lightning
- motors
- sending nad receiving communication signals
- computers, which in turn can do computations and improved communication
Ciro Santilli intends to move his beauty list here little by little: github.com/cirosantilli/mathematics/blob/master/beauty.md
The most beautiful things in mathematics are results that are:
- simple to state but hard to prove:
- Fermat's Last Theorem
- number of unknown rationality, e.g. is rational?
- transcendental number conjectures, e.g. is transcendental?
- basically any conjecture involving prime numbers:
- many combinatorial game questions, e.g.:
- surprising results: we had intuitive reasons to believe something as possible or not, but a theorem shatters that conviction and brings us on our knees, sometimes via pathological counter-examples. General surprise themes include:Lists:
- classification of potentially infinite sets like: compact manifolds, etc.
- problems that are more complicated in low dimensions than high like:
- generalized Poincaré conjectures. It is also fun to see how in many cases complexity peaks out at 4 dimensions.
- classification of regular polytopes
- unpredictable magic constants:
- why is the lowest dimension for an exotic sphere 7?
- why is 4 the largest degree of an equation with explicit solution? Abel-Ruffini theorem
- undecidable problems, especially simple to state ones:
- mortal matrix problem
- sharp frontiers between solvable and unsolvable are also cool:
- attempts at determining specific values of the Busy beaver function for Turing machines with a given number of states and symbols
- related to Diophantine equations:
- applications: make life easier and/or modeling some phenomena well, e.g. in physics. See also: explain how to make money with the lesson
Good lists of such problems Lists of mathematical problems.
Whenever Ciro Santilli learns a bit of mathematics, he always wonders to himself:Unfortunately, due to how man books are written, it is not really possible to reach insight without first doing a bit of memorization. The better the book, the more insight is spread out, and less you have to learn before reaching each insight.
Am I achieving insight, or am I just memorizing definitions?
Cool data embedded in the Bitcoin blockchain Bibliography Updated 2025-04-24 +Created 1970-01-01
Other Bitcon analysis:
- "Annotated blockchain project"Does the same as this page, just that it is an uncomprehensible mess of broken links. But they have soe good ideas!
- etherpad.mit.edu/p/r.e33d2e7230fafc0612a0f2e7ebc87bae
- etherpad.mit.edu/p/r.19b7b3e2c5ea08a61cb0bef0aeb213fd image list (February 8, 2017) We tried going over it, but it is just too much work, the huge majority of the results are just AtomSea & EMBII so not that interesting.
- archive.ph/Zz7m5
- www.reddit.com/r/Bitcoin/comments/5wax5v/a_group_is_working_on_building_a_fully_annotated/
- archive.4plebs.org/pol/thread/111742853/
Their main techniques seem to be:and:mkdir binout for file in blk*dat; do echo "$file"; binwalk --dd='.*' "$file" -C binout/. --log=binout/"$file""res.txt"; donewhich seem promising.mkdir subfileout for file in blk*dat; do mkdir subfileout/"$file"; done for file in blk*dat; do echo "$file"; hachoir-subfile --category=image,video,audio,container,archive,misc "$file" subfileout/"$file" > subfileout/"$file""subfile.txt"; doneTODO how to they automatically map back to transaction IDs? There is a line "Script to add the TX ID to each file." Our attempts: Section "Get transaction id from position in dat file"
Cool data embedded in the Bitcoin blockchain Cursed ordinal Updated 2025-04-24 +Created 1970-01-01
These were ordinals that were only indexed in later versions of the script. So to prevent changing the useless indices of existing ordinals, they gave them negative numbers.
Some examples:
- ordinals.com/inscription/4b9a822a057743813efbefa0dd21d0a01342ee793ce2ce5bd499a5f262187553i0 first inscription with no mime type.
- ordinals.com/inscription/2fa287270e4203ca2fc9f82ea3de7a0f7b785875791a76387ef6f4ccbb54eee2i0 is -38:is bugged because it is missing the mime type, on Python:because the
[b"'a\xf9\x19X%\xa8Q\x87SP\xe5\xf2H\xa6\xeew\x0e\x81\xa5hl\xcd\xaa\x97e\xfeqJ\x16\x12?", OP_CHECKSIG, 0, OP_IF, b'ord', 1, b'text/plain', 0, b'Hello World, this is a Rust Taproot test\xe2\x80\xa6', OP_ENDIF]1should instead beb'\x01.
Because the people who are crazy enough to think they can change the world are the ones who do.
This is a good book. It is rather short, very direct, which is a good thing. At some points it is slightly too direct, but to a large extent it gets it right.
The main goal of the book is to basically to build the Standard Model Lagrangian from only initial symmetry considerations, notably the Poincaré group + internal symmetries.
The book doesn't really show how to extract numbers from that Lagrangian, but perhaps that can be pardoned, do one thing and do it well.
50,000,000x Magnification by AlphaPhoenix (2022)
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