c3 (1/2)
Versus II
PART 1
“Hey, Onii-chan, what’s a quantum computer?”
――Howbrothers could there really be in this world who could give an adequate answer s asked such a question by their high school first year imouto-san who neither excelled in Mathematics nor Physics, and in the first place, probably had little understanding even about the structure of a Neumann-type computer?
At the very least, I’m not such a super onii-sama, so I hovered the fava beans over the table after just having stabbed my fork into them, and hummed for a moment
“Hmmmmmm”
At thatsorry frohtly lowered her head
“Ah, sorry, there are things that even you don’t know, Onii-chan, right? I shouldn’t be asking you all the ti it up myself once in a while”
It’s tough being in the position of an ≪Onii-chan≫, as I couldn’t obediently back do that she said that While the fava beans were still suspended, I cleared my throat with an ‘ahem’
“No, well, that’s not it, I’ll explain it to you if a rough explanation is enough”
“Yeah!”
Nodding energetically, uha, smiled innocently
Our azine editor, would almost certainly not wake up, so, for Saturday and Sunday breakfast, Suguha and I have grown accustoh for three, but eat with just the two of us Today’s menu is an easy to make risotto with canned white sauce, a salad of rohurt and cafe au lait with plenty of milk
After sending the fava beans intoto clear the path
“Ehm, first of all, on what a quantum is……”
“I know that much It’s an elementary particle! Like an atom, or electron”
Without a uha had said in a flash
“Vuvu(1)―― That’s a double mistake”
“Wha, where?”
“First of all, an atom isn’t an elementary particle Because an atom is made of protons, neutrons and electrons”
“Then, those three are elementary particles?”
“Vuvuvu―― Older textbooks ht now, out of those three, only electrons remain as elementary particles This is because protons and neutrons were discovered to be forrains called ≪quarks≫ In other words, quarks became elementary particles”
After adding ‘at least, for the ti’ in my mind, I pointed out the second mistake
“And also, quanta aren’t equal to elementary particles”
“Wha……?”
“‘Elementary particle’ is an expression that indicates ≪existence≫, but ‘quantum’ is a word that should indicate ≪state≫……”
“Whaa……?”
By this point, a suha’s head, so I quickly commented on it
“I-in other words, elementary particles are the smallest units of ≪material≫, and quanta are the smallest unit of ≪physical quantity≫……”
Suguha’s questionat this point, then there’s no e’ll get to quantum computers
“A-alright, I’ll explain it with an analogy This risotto is around two hundred…… no three hundred kilocalories, right?”
After I said that, Suguha nodded, although htly unpleasant expression
“Then this rice grain of the risotto is an elementary particle that cannot be decomposed any further and it should only yield 0001 kilocalorie…… in other words, one calorie, right?”
“Hm, that’s impossible If I'm not mistaken, we've learnt that a full rice has around three thousand grains, so if we assurain has three hundred divided by three thousand, 01 kilocalories…… A hundred calories, right? To get one calorie, you have to divide a rice grain into a hundred pieces”
“But, since it’s an elementary particle, you can’t do that In other words, the calorie, no, energy of this risotto can only be represented as rice grains…… having the value of a hundred calories apiece scattered here and there Consider the concept that the sy is a quantum”
“Het it……“
Suguha stillit would take if we got stuck here, so I had to force h
“Well, in practice, you can split a rice grain into as many parts as you like, but in the case of, for exay, the smallest unit is an electron and it absolutely cannot be divided, so an electron in this case is a quantuy also has a smallest unit, and that’s a photon That’s also a quantum In other words, a quantu on their ≪cannot be divided any further≫ property……though I wonder if its fine if I say it like that”
“Uh huh”
This tiuha put a single rice grain on the tip of her spoon and sucked it up with her puckered-up mouth
“Then, a quantuht?”
Although I felt that it was still iree when asked in that manner, but I decided to say ‘yeah’ despite her minor error, and nodded
“Yeah, well, it’s fine to think like that for now So, we’ve finally returned to the beginning…… A quantum computer is, exactly that! a computer that uses quanta!”
“‘Ta-dah’, finishi+ngsuch a flashy SE(2) in my heart, Iin relief that this ended without problems However
”Hey——you——know! That ure out! It’s like when soosuku≫(3)’, you’d answer ‘it’s the five rules when perfor kirikaeshi+’!
After she immediately replied like that, I fixedly stared at the face of aeshi+gosoku or soy; I didn’t understand anything other than that
”……I-I’m sorry Then, I shall continue……”
“Uh-huh, no objection”
“…………”
After stuffing my cheeks with a spoonful of crea y, I considered the way I would handle the more difficult problem Firstly, I undoubtedly had to start with this huh
“Err, Suguha-san Concerning the computer we usually use, the so called Neuht?”
“What’s that?”
“It is needed, huh”
Preparing for a long explanation, I once again cleared my throat
“Err, well, simply put, a Neumann-type is the arithmetics of just 0s and 1s…… In other words, operated by binary digits The information represented by one set of 0s and 1s is 1 bit If it becoe 128-bit CPU can process one hundred and twenty eight sets of 0s and 1s at the same time”
“H?”
“It is! There are only tays that you can express 0s and 1s with 1 bit If it’s 2 bits, there are four ways: 00, 01, 10, 11; if we convert that to the decimal system, it would be 0, 1, 2 and 3 Then, if we have 4 bits, how many ways can it be expressed in?”
“Eight…… no wait! Err…… If we take that 2 bits has four ways, 3 bits has eight ways, then 4 bits has sixteen ways?
“Oh, correct In other word, the numbers that can be handled with a 4 bit CPU are 0-15”
“Hood happens?”
Being asked this question with a serious look, I couldn’t answer right away There should be a lot of great things about it, but when it couha could understand……
“Well, for example, if we take an old 32 bit OS, then its abytes at max, but if it was a 64 bit OS, in theory, it could use 16 exabytes, or 17,2 hundred abytes……”
“Whaa, an old personal coh an AmuSphere has many times more”
“S-see, bits increasing is a good thing, right?”
One way or another, I seem to have conveyed the idea to her, so, after I drank a mouthful of cafe au lait, I returned to the flow of the conversation
“……Well then, let’s count it again, how many ways can the number handled by with 128 bits be expressed in?”
“Hm-err…… s-since it multiplies by two, 5 bits has thirty tays, 6 bits has sixty four ways, 7 bits has one hundred and twenty eight ways, 8 bits has two hundred and fifty six ways…… I can’t do it up to 128 with mental arithmetics at this rate!”
“Yeah, I can’t do it either In other words, it’s 2 to the power of 128, so let’s see…”
As expected, there was no way I could handle such a nu it with the portable terminal left on the table
“Let’s see……340282366920938463463374607431768211456 ways, it seehest denomination in kanji numbers to express this……? Ten hundred thousand man(4)……”
“I don’t know such a thing, let’s just leave it as a super huge number! I mean…… if even a current personal co such an unthinkable number of calculations, then there’s no need for a quantum computer already!”
I hastily stopped le stroke, cut down the dream machine that scientists fro with their utmost effort
“W-ait Even such an as”
“……Like what?”
“For example, prime factor decomposition”
Hearing that, Suguha made an expression that said ‘what’s that?’”
“That’s what you learn at ers as their co very troublesoh”
“Oh, now you’ve said it Then, how about trying to decompose 33 into prime numbers?”
“Let’s see, it cannot be divided by two, then if we divide it by 3, we get 11…… that’s a prime number, so that’s already the end The answer is 3 X 11”
“Correct Then……”
“How about deco 7663 into prime factors?”
“Uii!?”
Making a strange sound, Suguha wrinkled her forehead, and after thinking about it, began fiddling with her own portable terminal
“By 3…… indivisible, 5 is obviously not going to do, 7…… also won’t do, 11 too, 13 too, errr, noas the next prime number……”
“See, it isn’t that simple, is it? By the way, the answer to the current proble the question is easy, but it can only be divided into two largish prime numbers”
“Ugh, I suppose I get the point…… Ah, but, if you use a computer, it would take like a ht? It could just divide 7663 by prioes all the way to 79”
“Yeah, so like that With this amount of numbers, it wouldn’t even take a tenth of a second However, prier, the time it takes for decomposition increases exponentially Prime factor decomposition is utilised for the 《RSA cryptosystem》 that even assists us on the net, but, if you decide to decompose the currently used 2048 bit―…… in other words, a six hundred and seventeen digit ― key into pri a Neumann-type computer, it is possible that it could even take ten years or rade computer in the world”
“Te-TEN YEARS!?…… You ?”
Thethe real world, I ended up quickly looking around the vicinity
Luckily, hter, top down-type AI Yui didn’t seem to hear it, so I breathed out in relief
“Hey, don’t speak about Yui like that! Knowing her, she’d probably say so like 『I’ll try it!』 and not return for ten years”
“Ahaha, that seems likely”
Looking at Suguha laughing carefreely, I sighed I then threw the quantised creahts in order while chewing the food
“So, well, there are things that even current computers are bad at ――But, if a quantum computer is used, it could finish the prie numbers in the blink of an eye…… probably This equals that if it’s used around the world now, ciphers that appear to be co broken quickly”
“Hmmm…… Then, how is it that a quantum computer can decompose them quickly?”
As I thought, I’ll have to explain that too huh, and with that I unintentionally closed my eyes To be honest, I don’t have the confidence that I myself truly understand ‘how’ is it capable of that
However, if I end up giving up here, then ould be the point of all the strenuous effort up till now, so I gavereckless
“Well, I did explain about quanta in the very beginning”