#ehrenfest

[aubdrewanchel]

I've seen many versions of this, so I made AoaB version as well

[ahb-writes]

Book Review: 'Ascendance of a Bookworm' #21 (4.9)

Ascendance of a Bookworm #21 (4.9) by Miya Kazuki, You Shiina, Quof

adventure

fantasy

magic

library science

librarian

My rating: 4 of 5 stars

Poison! Thievery! Betrayal! Whatever wayward designs within which these characters find themselves, the precipice of change looms all the more dangerous when the urgent call of a nefarious other threatens to push them off the edge. In ASCENDANCE OF A BOOKWORM v21, Ferdinand's forthcoming departure to the Duchy of Ahrensbach is equally stymied and accelerated by a frantic side story reminiscent of Poe's The Purloined Letter.

The circumstances surrounding Ferdinand's forced dismissal is an awkward and dangerous mix of known and unknown dilemmas. Everyone knows Lady Georgine has her sights set on Ehrenfest the Eighth. But does Georgine's revenge exist merely to spite Ehrenfest? Does she hope to elevate Ahrensbach in Ehrenfest's ashes? Does she hope to monopolize Ferdinand, personally? Who else is she willing to sacrifice to get what she wants? Her husband? Her daughters? Nobody really knows. And so, with little beyond a guard knight, a scholar, and his own intuition, Lord Ferdinand embarks on the newest chapter of his tumultuous young life.

Fortunately, before all of that sadness weighs down the narrative, the author saw fit to insert a good deal of drama with a pseudo-side-story that consumes roughly 40% of the book.

In short, someone weasels into the High Bishop's chambers in the temple and thieves the Bible. At length, Lady Rozemyne and the gang must conduct a thorough and detailed search to find the culprit, bring them to justice, and retrieve the stolen artefact. The whole ordeal involves deception, kidnapping, a renewal of Lower City allies, a confirmation of Noble's Quarters egotism, and some good old fashioned violence.

The Bible-stealing incident is a great example of what makes this light-novel series so enchanting. At nearly two dozen volumes, readers know, explicitly, that everything will work out fine. And yet, the narrative construction quickly and abruptly nudges readers with the implicit presumption that things are going to be bumpy for a while. Things may work out for the core cast of characters in the end, but the knowledge they gain from surviving each stress test may well change them for good.

ASCENDANCE OF A BOOKWORM v21 is a fond farewell to Ferdinand. The book makes no short mention of the young man's growing emotional entanglement after meeting a certain bookworm (often riddled with worry). The sendoff is sweet. And reality sets in fast. Soon, Rozemyne will require a whole bevy of overeager friends and family to keep her within her remit when her next term at the Royal Academy begins. And just as there will be fewer eyes available to watch Ferdinand's back in Ahrensbach, so too will there be fewer eyes available to keep Rozemyne on course.

❯ ❯ Light-Novel Reviews

[honeyjello]

Saint Ehrenfest in the furthest Hall

[yurgenschmidt]

[unpeudephysique]

Le théorème de Noether

Amalie Emmy Noether est une mathématicienne allemande décrite par Albert Einstein comme « le génie mathématique créatif le plus considérable produit depuis que les femmes ont eu accès aux études supérieures ». Le théorème de Noether joue un rôle central en mécanique quantique.

Le théorème de Noether démontre qu’il y a équivalence entre la conservation d’une grandeur en physique classique et l’existence d’une classe de transformations qui laisse invariante les lois physiques d’un système. L’invariance des lois physiques d’un système dans une transformation porte le nom de symétrie du système.

Nous allons démontrer le théorème de Noether dans un cas particulier : l’équivalence ente l'invariance par translation dans le temps et la conservation de l'énergie.

Soit L(q,q_point) le Lagrangien d’un système quelconque. La condition de symétrie par rapport au temps induit qu’il ne doit pas dépendre explicitement du temps. Sa dérivée par rapport au temps ne doit donc pas contenir de terme en dL/dt :

Combinons cette formule avec l’équation d’Euler-Lagrange :

Il vient :

Ceci conduit à l’équation remarquable suivante :

On peut donc déduire de la seule condition de symétrie par rapport au temps que l’expression suivante :

est invariante. On vérifie facilement que cette expression est celle de la conservation de l’énergie du système.

On peut démontrer de la même façon que :

l'invariance par translation dans l'espace selon une direction donnée entraîne la conservation de la quantité de mouvement dans la même direction ;

l'invariance par rotation dans l'espace entraîne la conservation du moment angulaire ;

dans la théorie de la relativité restreinte, l’invariance par transformation de Lorentz entraîne la conservation du vecteur énergie-impulsion.

Symétries en mécanique quantique

Soit une symétrie S et un opérateur A définis dans un espace de Hilbert. Par définition de la symétrie on peut écrire : 

En mécanique quantique, les symétries sont souvent associées à un groupe de Lie (voir les posts consacrés aux groupes de Lie). Dans ce cas S peut être représenté par un opérateur unitaire U(g), g faisant partie d’un groupe G :

Si le groupe G est continu et différentiable, on peut exprimer U en fonction d’un paramètre réel tau et d’un générateur infinitésimal du groupe de symétrie qui prend la forme d’un opérateur hermitien B :

Un opérateur hermitien peut être associé à une observable, c’est-à-dire à un opérateur de mesure. Si le système est invariant, son hamiltonien est laissé inchangé par l’application de l’opérateur unitaire U. Cela se traduit par le fait que l’opérateur hamiltonien commute avec B.

Théorème d’Erhenfest

Soit Bmoy la valeur moyenne du résultat des mesures obtenues avec l’opérateur B :

Nous allons nous intéresser à son évolution dans le temps :

L’équation de Schrödinger nous permet d’écrire : 

Comme par ailleurs :

il vient :

On obtient donc le résultat tout à fait fondamental suivant : non seulement B agit comme un générateur infinitésimal de la symétrie mais, en tant qu’observable, B est associé à une quantité physique conservée dans le temps. C’est la transcription en physique quantique du théorème de Noether.

On entrevoit ici le caractère particulièrement puissant du formalisme de l’algèbre de Lie en mécanique quantique. Il permet de d’associer aux opérateurs de symétrie une observable correspondant à une grandeur physique conservée au cours des évolutions du système !

Nota : Paul Erhenfest est un physicien autrichien, ami de Bohr et d’Einstein, qui contribua au développement de la mécanique quantique.

Pour en savoir plus :

posts sur la mécanique quantique 

post sur le formalisme quantique

post sur les espaces vectoriels et les groupes de Lie

post sur les algèbres de Lie

formalisme quantique

groupes et algèbre de Lie

index

[aubdrewanchel]

Another version of this

[aubdrewanchel]

Daily ascendance of a bookworm meme

Royal Academy in P1 be like:

[aubdrewanchel]

Ehrenfest: from a middle duchy to a republic ᶠᶠ (Dawnfall of Bibliophile part 1)

(This is just random ff on AoaB I wrote after two months of writing block. Easter eggs included. Enjoy!)

(English is not my first language)

♜♜♜♜♜♜♜♜♜♜♜♜♜♜♜♜

I laid my head on my desk. It fought back the sleepiness. I rubbed my eyes to keep them open and frowned at the sight of the study books in front of me.

Curse the Yurgenschmidt's emperor for establishing compulsory schooling.

The bell signaled the start of the last period for the day - history. I hated history with all my might. Don't get me wrong, I love myths and legends, but learning about all the kings, emperors and presidents made my head dizzy.

I listened to the teacher talking about one of Ehrenfest's greatest figures. She was talking about Lady Rozemyne, the so called Saint of Ehrenfest. She had a great impact on today's technology. The republic of Ehrenfest, in that time just a middle duchy Ehrenfest, was suffering from the last civil war.

Lady Rozemyne invented many things to help her people and overall raise the status of our duchy. The historians argue about many mysteries surrounding her. Some says she was born genius, other says she had alien civilization help her and give her the knowledge to build things like printing press. And there are many more bizarre theories like that.

People also like to talk about the legend of her being a saint or reincarnation of a goddess. Which I would love to believe, but apparently, those are only stories, since science proved no things like magic existed.

I wish I could live in a world with magic and mana.

The other interesting thing about her was that she came out of nowhere. She literally had no parents. When the archaeologist found her corpse and scientists studied her genetics, there was no match with anybody from her family. It was like she was born out of thin air.

Hehe... Try explaining this, science.

I smirked at the thought that there actually might have been some magic. Lady Rozemyne was great source of mysterious legends.

The class came to end with me still fantasising about world with cool magic and epic monsters.

I went straight to my grandparents' house. I live on the west part of the capital city New Eisenreich. It was built around the original city Eisenreich, which is now more of a historical monument than a livable place, with the Republic's government located in the former noble quarter and the duke's palace.

"I'm back, grandma." I took off my shoes and went to hug my grandma named Effa, which she told was name passed down for many and many generations.

"Finally it's Winday, I can now repose for the rest of the weekend." I yawned. I was excited to finish the book I started last Fireday.

"Come eat before you hole up in the library, Rozelle."

I obediently walked to the kitchen and served myself potatoffel salad and fried bird. The smell made my stomach growl. I prayed before digging in. I loved mayonnaise salads, especially the potatoffels ones, and soon enough my plate was all clean.

"You're so thin, Rozelle. You should eat more." My grandma clicked her tongue, clearly displeased. "I'm about to bake some apfelsige pies, so be sure to come down when they're ready."

I happily skipped to my grandparents' library. There were no windows, as not to damage all the books by direct sun light , so I needed a flash light to find the book I wanted. I found it in instant, since I already knew where was what book, and I took it to my room.

I gently placed it on the desk, as not to impair the cover. It was one of the oldest printed books and it was my father's family inheritance. When I was little, my grandfather would always read some of those old books for me before sleep. He said we shared blood with Lady Rozemyne who made them, and that was the reason for having so many old printed books.

As I said before, Lady Rozemyne had no genetic connection with the archduke's family or any other archnoble family, but she somehow shared ancestors with me. Which was another mystery to her life.

I carefully flipped thought the pages of the book. It was a storybook about legendary magic beasts, so-called feybeasts. This one was named goltze. My eyes scanned the text with so much joy. I fantasised about being a knight who fought his foes with magic.

"I'm ever so honoured to be chosen as your guard knight, milady. Hencefort I shall server you with all my skill and power."

I let out a sigh full of envy. I gently turned the page and kept reading. I was so absorbed in the story, that I haven't realised grandmother was calling for me. I closed the book and went to the kitchen once again. As soon as I opened the door, the sweet smell of apfelsige pie tickled my nose. I took a slice and immediately started eating.

Suddenly my grandma put a book infront of me. "I discovered this when cleaning my mother's old clothes chest. You can find it a place in the library." She smiled warmly.

I grabbed the book. "I sure will! What is it about anyways?" I carefully turned few pages. "Wait, it's not printed?! How did that even get here? Thanks 'ma."

I couldn't wait to read it. I sat next to the window, so I would have enough light, and I started. I was immediately out of words. It was about magic! Spells, body enchantments, prayers and divine blessings, magic tools and divine instruments, everything!

I devoured every letter. I carefully observed all the illustrations. When suddenly, a very familiar drawing appeared. It was a magic tool in the shape of a ring. I realised, I've already seen it somewhere. I took off the necklace my mom gave me for birthday. It was the same golden ring with a blue stone as the one I had on a stringed up on a twine, since it was too big to wear.

I run up to my grandma. "Grandma, where is this ring from?! I really need to know, it's super important."

"I'm not entirely sure. This might be from your mother's side of family, so you should ask Lutzy instead."

I hung my head sadly. That didn't help at all. "'Kay. I'll ask mom later."

I went back to reading. It was fun, sure, but I haven't got much actual information from it, since it was written in even older language, than in those printed books from Lady Rozemyne's era. The only piece of information I was able to decipher was that they we're used for controlling one's mana.

I reeeally hate how science tries to hide the existence of magic in our history. I'm pretty sure it was a real thing.

It took the ring off the twine. I rolled it in my hands, wondering just how big fingers had it's former owner. I would be able to fit two fingers in it, it not more. Out of curiosity I tried it on. It immediately shrunk in size and now fitted my finger perfectly.

"Waaah...! Whatta? Was that an actual magic?!" I suddenly felt very light headed. It was like my energy was sucked away. I took the ring off and the flow stopped.

I grinned. Just you wait fantasy world, I'm going for you!

(Word count: 1219)