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j_bertolotti, to random
@j_bertolotti@mathstodon.xyz avatar

Installing Duolingo in the "games" folder of my tablet so my son discovers it by himself and start practicing Italian without feeling it is a chore: success!

j_bertolotti, to random
@j_bertolotti@mathstodon.xyz avatar

Goodhart's law: "When a measure becomes a target, it ceases to be a good measure".

This also applies to grades in school (including University).

j_bertolotti, to random
@j_bertolotti@mathstodon.xyz avatar

Why do you keep all of these PhD theses?
For instance because there is a very high chance that during a meeting I can just grab one and show one of the figures to help me explain something.

j_bertolotti,
@j_bertolotti@mathstodon.xyz avatar

Corollary: if you are a PhD student aiming for a research career (whether inside or outside academia), when the time comes print a bunch of copies of your thesis, ideally in a nicely portable format like B5, and give it to the people you want to know about you (and/or those who you think will be interested in your research).

j_bertolotti, to physics
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The ability to follow hashtags is nice, but following means I have to continuously remind myself that people probably don't want a lecture explaining why they are making a naive mistake 🤐

j_bertolotti, to random
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#PhysicsFactlet
Common misunderstanding about #Entropy: the two configurations below have exactly the same entropy, and in both cases the entropy is zero (as you know exactly where each dot is, so there is only one possible microstate they can be in).

prismika,

@j_bertolotti I like this demonstration! Is there a perspective from which the entropy of the second system is lower? Maybe if we knew something like the minimum distance between points in the box instead of the whole configuration?

j_bertolotti,
@j_bertolotti@mathstodon.xyz avatar

@franco_vazza Let me try to be less confusing: the usual definition of entropy as being propprtional to the log of the number of microstates is not meant to be used when you can't take a statistical ensemble (e.g. the case N=1 like here). On the other hand the Kolmogorov complexity can be applied to this case too.

j_bertolotti, to cooking
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Rediscovering in a after not using one for ~15 years.

j_bertolotti, to random
@j_bertolotti@mathstodon.xyz avatar

The page is still a bit under construction, but I have been invited to give a tutorial at EOSAM (next 9-13 September in Naples) about scientific animations and visualizations. If you are going to be around, come and say hi!
#Optics
https://www.europeanoptics.org/pages/events/eosam-2024/program/tutorials-1698149154.html

j_bertolotti, to random
@j_bertolotti@mathstodon.xyz avatar

"Please fill this anonymous survey"
Proceed to ask enough personal questions that anyone with two working neurons can uniquely identify me 🤦‍♂️

TonyVladusich,
@TonyVladusich@mathstodon.xyz avatar

@j_bertolotti

Tbf it is quite hard to find people with 2 whole working neurons these days

j_bertolotti, to ubuntu
@j_bertolotti@mathstodon.xyz avatar

I assume there is a very good technical reason for to use , but honestly, after years of getting more and more approachable by casual users, having to fiddle with the command line every few weeks because the system complains it can't update this or that feels like a huge step back.

DiogoConstantino,
@DiogoConstantino@masto.pt avatar

@j_bertolotti I do agree that even only one is an issue. But I don't think it's a huge step back.

j_bertolotti,
@j_bertolotti@mathstodon.xyz avatar

@DiogoConstantino e.g. updating Firefox is a pain every single time.

j_bertolotti, to random
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j_bertolotti, to random
@j_bertolotti@mathstodon.xyz avatar

Next time I have to advertise my "analytical mechanics" module to students I will just show them this comic and ask them whether they are interested in learning deep magic 🙃
https://xkcd.com/2904/

j_bertolotti, to physics
@j_bertolotti@mathstodon.xyz avatar


A quantum simple pendulum.
The pendulum position is spread out, with opacity here being proportional to the probability that the pendulum is at that position at a given time. The average position of the quantum dynamics is the same as the classical pendulum dynamics (Ehrenfest theorem).

Technicalities: I used the Crank-Nicholson method to evolve the system in time. This is a 1D problem, and the only variable I considered was the angle, with the initial state being a Gaussian.

Schematic drawing of a simple pendulum oscillating, with its quantum version represented as a distribution of pendula with their transparency proportional to the probability to be at a certain position at any given time.

j_bertolotti,
@j_bertolotti@mathstodon.xyz avatar

@secular Yes, you are right. This is only strictly true for an harmonic potential.
My mistake.

secular,

@j_bertolotti By the way, this is a fun example, thanks for sharing! Especially as it behaves differently to a harmonic oscillator. I don't have Mathematica though, so have had to try to reproduce your code using Python.

j_bertolotti, to random
@j_bertolotti@mathstodon.xyz avatar

When people graduate from University they should be given a black belt, to symbolize that now they reached the level where they can truly begin to learn the subject, like they do in many martial arts.

j_bertolotti, to DnD
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Archeological findings (at my parent's home).
One of the many manuals I owned and that I never managed to use.

j_bertolotti, to random
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Find a job you love and you will realize you actually love only a small fraction of it, while most of your time is spent doing the parts you don't like at all.

dougmerritt,
@dougmerritt@mathstodon.xyz avatar

@j_bertolotti Ouch! That has both the ring of truth as well as the Peal Of The Bell Of Doom.

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