Debugging quantum concepts

Reality is a superposition of eigenstates. Even if we use the pilot-wave formalism, in which a particle has definite position or momentum, the pilot wave itself is in a superposition.

— Me@2012-04-16 2:27:20 PM


Physics reality is NOT a superposition of eigenstates. If physics reality was a superposition of eigenstates, there would have never been any interference patterns.

For an experimental setup, what is in a superposition is the quantum state, which is a tool for deducing probabilities of different potential measurement results.

“A quantum state is a superposition of eigenstates” just means nothing more than that we need to use individual probabilities of the eigenstates to calculate the probabilities.

A quantum state, which is represented by a wave function, is logical, mathematical, conceptual, and linguistic in nature. A quantum state is NOT physical. A quantum state is NOT reality. A quantum state is NOT directly corresponding to a physical reality (aka observable events, measurement results, etc.)

A quantum state is NOT even corresponding to a probability directly. (If a quantum state was a probability, there would have never been the phenomenon of interference.) Instead, a quantum state is corresponding to a probability amplitude, which is used for calculating probabilities.

— Me@2023-03-16 09:57:07 AM



2023.03.17 Friday (c) All rights reserved by ACHK

Computing Note, 5


From Personal Computer[s] to Personal Robots 


optical fibers

In the beginning of the optical fiber research, 
there were a lot of difficulties. But I thought if 
[I succeeded], the research payoff would be huge, 
because it could create a whole new world. 
"Mingpao Monthly"

        By the Father of Optical Fibers 


Make Robot as inexpensive and as useful as 
Personal Computer -- Personal Robot



2023.03.15 Wednesday (c) All rights reserved by ACHK

Corsair Vengeance RGB Pro







— Me@2023-03-12 10:28:29 AM



2023.03.13 Monday (c) All rights reserved by ACHK


A Vulkan and OpenGL overlay for monitoring FPS, temperatures, CPU/GPU load and more.






— Me@2023-03-07 09:14:51 AM



2023.03.07 Tuesday (c) All rights reserved by ACHK

Ex 2.1-2 Particle in a Box

Quantum Methods with Mathematica


Reproduce Figure 2.1-1 …


phi[n_, x_] := Sin[n Pi x]

p[n_] := Plot[phi[n,x],{x,0,1}]

GraphicsColumn[{p[1], p[2], p[3]}]

— Me@2023-03-03 01:30:46 PM



2023.03.05 Sunday (c) All rights reserved by ACHK

Intermediate states

What happens in the interval between the initial and final states of the interaction process?

What happens in between is everything and nothing. There is no privileged clearcut answer what happened that would be physically meaningful. It’s really the very basic point of quantum mechanics that only results of measurements are physically meaningful facts or observables; all other data are fictitious or uncertain. By the very definition of your problem, no measurement took place in the intermediate states which means that no sharp answers to any questions were generated, no answers or values became real or privileged or facts.

But unlike classical physics, quantum mechanics says that not only the probabilities of each history matter. All the relative phases matter, too.

— answered Jan 9, 2021 at 16:10

— Luboš Motl

— Physics StackExchange



2023.03.02 Thursday ACHK

人生 Presentation, 2.3

這段改編自 2010 年 4 月 24 日的對話。


那是 Paul Buchheit 講過的,我現在轉述成:























— Me@2023-02-28 11:16:42 AM



2023.02.28 Tuesday (c) All rights reserved by ACHK

Euler problem 10.2

Find the sum of all the primes below two million.

removeIf :: (a -> Bool) -> [a] -> [a]
removeIf p = filter (not . p)

sieveIter :: Integral a => [a] -> [a] -> [a]
sieveIter [] (x:xs) = x:xs
sieveIter (x:xs) acc
  | x^2 > last (x:xs) = reverse acc++(x:xs)
  | otherwise = sieveIter xss (x:acc)
    xss = removeIf (\n -> n `mod` x == 0) xs

primeList :: Integral a => [a] -> [a]
primeList xs = sieveIter xs []

pL :: [Integer]
pL = primeList [2..2000000]

f :: Integer
f = sum (takeWhile (< 2000000) pL)

— colorized by palette fm

— Me@2023-02-25 12:35:57 PM



2023.02.26 Sunday (c) All rights reserved by ACHK

Zsh, 2

To install the Z shell (Zsh):

1. Read my blog post “Zsh” to follow the instructions point 1 and point 2.

2. In the Bash terminal, run


once, in order to get the config file generated.

3. Return to my blog post “Zsh” to follow the remaining steps.

— Me@2023-01-19 12:41:56 PM

— Me@2023-02-24 05:19:38 PM



2023.02.24 Friday (c) All rights reserved by ACHK

Looper, 6

Causal diamonds in time travel, 3


Time travel in the absolute sense is logically impossible.

If time travel was logically possible, it still could be logically consistent from the time traveller’s point of view, as long as he cannot see from the perspective of the meta time.

— Me@2016-06-01 07:10:51 AM

— Me@2023-02-23 12:13:20 PM



2023.02.23 Thursday (c) All rights reserved by ACHK

When physics meets biology

oli5679 on May 15, 2018

There was a really good chapter on his time in a biology lab in his book, “Surely you’re joking Mr. Feynman”. I have always remembered this quote:

When it came time for me to give my talk on the subject, I started off by drawing an outline of the cat and began to name the various muscles.

The other students in the class interrupt me: “We know all that!”

“Oh,” I say, “you do? Then no wonder I can catch up with you so fast after you’ve had four years of biology.” They had wasted all their time memorizing stuff like that, when it could be looked up in fifteen minutes.

sykh on May 15, 2018

Feynman was wrong on his view. The same thing could have been said of him and physicists. Oh, you spent your time memorizing formulas when it could be looked up in 15 minutes.

This is a nonsensical point of view for two reasons. [1] People in areas of their expertise tend to know a lot in that area off the top of their head because they have encountered this stuff so much that it has become memorized. That memorized knowledge comes from experience not a memorization exercise. [2] It’s also nonsensical because if you didn’t have a core set of knowledge memorized in your area of expertise and instead relied on spending 15 minutes looking up each fact necessary to understand a given situation you’d end up wasting your whole day just trying to understand the meaning of the problem.

— Hacker News



2023.02.22 Wednesday ACHK

Euler problem 10.1

Find the sum of all the primes below two million.

(defmacro sq (x)
  `(* ,x ,x))

(defmacro last-item (lst)
  `(car (last ,lst)))

(defun good-reverse (lst)
  (labels ((rev (lst acc)
         (if (null lst)
          (cdr lst)
          (cons (car lst) acc)))))
    (rev lst nil)))

(defun prime-sieve-a-list (input-lst)
  (labels ((sieve-iter (go-lst acc-list)
         (if (not go-lst) 
         (if (> (sq (car go-lst))
            (last-item go-lst))

             (append (good-reverse acc-list)
              (remove-if #'(lambda (x)
                      (mod x (car go-lst))
                 (cdr go-lst))
              (cons (car go-lst)

    (sieve-iter input-lst '())))

(defun range (max &key (min 0) (step 1))
  (loop :for n :from min :below max :by step
    collect n))

(defmacro prime-sieve (n)
  `(prime-sieve-a-list (cons 2 (range (1+ ,n)
                      :min 3
                      :step 2))))

(defun sum (lst)
  (reduce #'+ lst))

(sum (prime-sieve 2000000))

(time (sum (prime-sieve 2000000)))

— Me@2023-02-16 11:34:49 PM



2023.02.21 Tuesday (c) All rights reserved by ACHK


If you are using SSD, you should turn off the swap file:

1. In command line, run

swapoff --all

2. Backup the file


3. Then, in that file, comment out any lines that contain the word “swap”.

— Me@2023-02-14 05:00:26 PM



2023.02.15 Wednesday (c) All rights reserved by ACHK

Computing Note, 4


1. Use Computer Software to improve/[]upgrade 
your Brain Software  


2. Software Philosophy: 

Use it, enjoy it, but keep your ability 
to live without it. 

<<Conversation with God>>

Enjoy everything, but need nothing! 

(Even people? 
Especially people!) 



2023.02.11 Saturday (c) All rights reserved by ACHK

大恩養仇人 3

小恩養貴人 3

這段改編自 2021 年 12 月 15 日的對話。




























— Me@2022-11-05 12:54:58 PM

— Me@2023-02-09 12:24:10 PM



2023.02.10 Friday (c) All rights reserved by ACHK