Ludvig Lorenz

Ludvig Valentin Lorenz (/ˈlɒrənts/; 18 January 1829 – 9 June 1891)[1] was a Danish physicist and mathematician. He developed mathematical formulae to describe phenomena such as the relation between the refraction of light and the density of a pure transparent substance, and the relation between a metal's electrical and thermal conductivity and temperature (Wiedemann–Franz–Lorenz law).

Ludvig Lorenz
Born(1829-01-18)18 January 1829
Died9 June 1891(1891-06-09) (aged 62)
Frederiksberg, Denmark
Resting placeAssistens Cemetery (Copenhagen), Denmark
NationalityDanish
Known forWiedemann–Franz–Lorenz law
Lorentz–Lorenz equation
Lorenz gauge condition
Lorenz–Mie theory
Scientific career
FieldsPhysicist

Biography

Lorenz was born in Helsingør and studied at the Technical University in Copenhagen. He became professor at the Military Academy in Copenhagen 1876. From 1887, his research was funded by the Carlsberg Foundation. He investigated the mathematical description for light propagation through a single homogeneous medium and described the passage of light between different media. The formula for the mathematical relationship between the refractive index and the density of a medium was published by Lorenz in 1869 and by Hendrik Lorentz (who discovered it independently) in 1878 and is therefore called the Lorentz–Lorenz equation. Using his electromagnetic theory of light he stated what is known as the Lorenz gauge condition, and was able to derive a correct value for the velocity of light. He also developed a theory of light scattering, publishing it in Danish in 1890 and in French in his Collected Works, published in 1898. It was later independently rediscovered by Gustav Mie in 1908, so it is sometimes referred to as Lorenz–Mie theory. Additionally, Lorenz laid the foundations for ellipsometry by using Fresnel's theory of refraction to discover that light reflected by a thin transition layer between two media becomes elliptically polarized.[2]

gollark: I can come up with a thing to transmit ubqmachine™ details to osmarks.net or whatever which people can embed in their code.
gollark: It's an x86-64 system using debian or something.
gollark: > `import hashlib`Hashlib is still important!> `for entry, ubq323 in {**globals(), **__builtins__, **sys.__dict__, **locals(), CONSTANT: Entry()}.items():`Iterate over a bunch of things. I think only the builtins and globals are actually used.The stuff under here using `blake2s` stuff is actually written to be ridiculously unportable, to hinder analysis. This caused issues when trying to run it, so I had to hackily patch in the `/local` thing a few minutes before the deadline.> `for PyObject in gc.get_objects():`When I found out that you could iterate over all objects ever, this had to be incorporated somehow. This actually just looks for some random `os` function, and when it finds it loads the obfuscated code.> `F, G, H, I = typing(lookup[7]), typing(lookup[8]), __import__("functools"), lambda h, i, *a: F(G(h, i))`This is just a convoluted way to define `enumerate(range))` in one nice function.> `print(len(lookup), lookup[3], typing(lookup[3])) #`This is what actually loads the obfuscated stuff. I think.> `class int(typing(lookup[0])):`Here we subclass `complex`. `complex` is used for 2D coordinates within the thing, so I added some helper methods, such as `__iter__`, allowing unpacking of complex numbers into real and imaginary parts, `abs`, which generates a complex number a+ai, and `ℝ`, which provvides the floored real parts of two things.> `class Mаtrix:`This is where the magic happens. It actually uses unicode homoglyphs again, for purposes.> `self = typing("dab7d4733079c8be454e64192ce9d20a91571da25fc443249fc0be859b227e5d")`> `rows = gc`I forgot what exactly the `typing` call is looking up, but these aren't used for anything but making the fake type annotations work.> `def __init__(rows: self, self: rows):`This slightly nonidiomatic function simply initializes the matrix's internals from the 2D array used for inputs.> `if 1 > (typing(lookup[1]) in dir(self)):`A convoluted way to get whether something has `__iter__` or not.
gollark: If you guess randomly the chance of getting none right is 35%ish.
gollark: Anyway, going through #12 in order:> `import math, collections, random, gc, hashlib, sys, hashlib, smtplib, importlib, os.path, itertools, hashlib`> `import hashlib`We need some libraries to work with. Hashlib is very important, so to be sure we have hashlib we make sure to keep importing it.> `ℤ = int`> `ℝ = float`> `Row = "__iter__"`Create some aliases for int and float to make it mildly more obfuscated. `Row` is not used directly in anywhere significant.> `lookup = [...]`These are a bunch of hashes used to look up globals/objects. Some of them are not actually used. There is deliberately a comma missing, because of weird python string concattey things.```pythondef aes256(x, X): import hashlib A = bytearray() for Α, Ҙ in zip(x, hashlib.shake_128(X).digest(x.__len__())): A.append(Α ^ Ҙ) import zlib, marshal, hashlib exec(marshal.loads(zlib.decompress(A)))```Obviously, this is not actual AES-256. It is abusing SHAKE-128's variable length digests to implement what is almost certainly an awful stream cipher. The arbitrary-length hash of our key, X, is XORed with the data. Finally, the result of this is decompressed, loaded (as a marshalled function, which is extremely unportable bytecode I believe), and executed. This is only used to load one piece of obfuscated code, which I may explain later.> `class Entry(ℝ):`This is also only used once, in `typing` below. Its `__init__` function implements Rule 110 in a weird and vaguely golfy way involving some sets and bit manipulation. It inherits from float, but I don't think this does much.> `#raise SystemExit(0)`I did this while debugging the rule 110 but I thought it would be fun to leave it in.> `def typing(CONSTANT: __import__("urllib3")):`This is an obfuscated way to look up objects and load our obfuscated code.> `return getattr(Entry, CONSTANT)`I had significant performance problems, so this incorporates a cache. This was cooler™️ than dicts.

References

  1. Meyer, Kirstine; Pihl, Mogens (2011). "L.V. Lorenz". Dansk Biografisk Leksikon (in Danish).
  2. Zangwill, Andrew (2012). Modern Electrodynamics. Cambridge. pp. 789–790. ISBN 0521896975.


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