Bitcoin protocol data type Updated 2025-07-16
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ffplay multiple input files Updated 2025-07-16
TODO possible? superuser.com/questions/559768/ffplay-how-to-play-together-separate-video-and-audio-files
For synthesized streams like but it does not seem to accept multiple fails with:
sine we can do it e.g.ffplay -autoexit -nodisp -f lavfi -i '
sine=frequency=500[a];
sine=frequency=1000[b];
[a][b]amerge, atrim=end=2
'-i for some reason. So is there a way to open a file from some filter? E.g.:ffplay -i tmp.wav -i tmp.mkv -filter_complex "[0:a]atrim=end=2[a];[1:v]trim=end=2[v]" -map '[a]' -map '[v]'Argument 'tmp.mkv' provided as input filename, but 'tmp.wav' was already specified. Gift vs Grant vs Contract in the United Kingdom Updated 2025-07-16
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Quantum field theory lecture by Tobias Osborne (2017) Lecture 1 Updated 2025-07-16
Bibliography review:
- Quantum Field Theory lecture notes by David Tong (2007) is the course basis
- quantum field theory in a nutshell by Anthony Zee (2010) is a good quick and dirty book to start
Course outline given:
- classical field theory
- quantum scalar field. Covers bosons, and is simpler to get intuition about.
- quantum Dirac field. Covers fermions
- interacting fields
- perturbation theory
- renormalization
Non-relativistic QFT is a limit of relativistic QFT, and can be used to describe for example condensed matter physics systems at very low temperature. But it is still very hard to make accurate measurements even in those experiments.
Mentions that "QFT is hard" because (a finite list follows???):But I guess that if you fully understand what that means precisely, QTF won't be too hard for you!
There are no nontrivial finite-dimensional unitary representations of the Poincaré group.
Notably, this is stark contrast with rotation symmetry groups (SO(3)) which appears in space rotations present in non-relativistic quantum mechanics.
www.youtube.com/watch?v=T58H6ofIOpE&t=5097 describes the relativistic particle in a box thought experiment with shrinking walls
Schrödinger equation for a one dimensional particle Updated 2025-07-16
We select for the general Equation "Schrodinger equation":giving the full explicit partial differential equation:
- , the linear cartesian coordinate in the x direction
- , which analogous to the sum of kinetic and potential energy in classical mechanics
Equation 1.
Schrödinger equation for a one dimensional particle
. The corresponding time-independent Schrödinger equation for this equation is:
Equation 2.
time-independent Schrödinger equation for a one dimensional particle
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Quantum field theory lecture by Tobias Osborne (2017) Updated 2025-07-16
This is a bit "formal hocus pocus first, action later". But withing that category, it is just barely basic enough that 2021 Ciro can understand something.
By: Tobias J. Osborne.
Lecture notes transcribed by a student: github.com/avstjohn/qft
18 1h30 lectures.
Followup course: Advanced quantum field theory lecture by Tobias Osborne (2017).
Resource Description Framework Updated 2025-07-16
This is one of those idealistic W3C specifications with super messy implementations all over.
The Linux kernel responds to ICMP directly Updated 2025-07-16
There is no userland process for it, it is handled directly by the Linux kernel: unix.stackexchange.com/questions/439801/what-linux-process-is-responsible-for-responding-to-pings/768739#768739
There are unlisted articles, also show them or only show them.