SCHORÖDINGER CAT NIB
슈뢰딩거 고양이 닙
This will be a very simple post, since I'm introducing only a single nib.
I didn't bring any other pens for this post.
It's unprecedented for me to buy a nib.
In spite of I haven't bought a nib until now, I could not repel the temptation since I was a physicist.
Schrödinger's cat must be the most famous cat in the world.
Now, it's time to savor every detail of the nib, though nobody would be interested in this tedious story.
The first line is the Schrödinger equation.
On the left hand side, the "operator" Hamiltonian is applied to the Greek capital letter psi, which is conventionally used to denote the "wave function."
On the right hand side, we see the imaginary unit "i" times the Planck constant "h bar," which is simply h divided by 2 times pi, and the product of these two are again multiplied to the partial derivative of the psi with respect to the time.
Seriously, are you really going to cover this long-winded story?
I can't surely discuss all the details, but I'd like to present some remarks.
The first thing I'd like to mention is "Wheeler-DeWitt equation," which was proposed to describe the whole universe.
Roughly speaking, it deals with the single wave function of the whole universe.
As some of you might have noticed, Schrödinger equation describes the minute scale, and this seems to contradict with the giant scale of the universe.
Albeit the formulation of quantum gravity has not yet been finished, it is the right moment where we rely on the quantum gravity.
Here comes the crux: Schrödinger equation tells how the wavefunction evolves as time goes on.
Now, can we say the same thing to the Wheeler-DeWitt equation, simply saying the universe never evolves? (Since the right hand side, the time derivative term, vanishes)
As the name says, General Relativity says there's no absolute time.
This brings a conteroversial issue, the so-called "timeless physics."
At least, if we are naively going to write "d\Psi / dt = 0," the "t" must not be the time we know.
Even though it's hard to say Wheeler-DeWitt equation and Schrödinger equation have direct connections, it's impressive the theory of nano scale and that of cosmological scale have a similarity.
The next thing to point out is there are many Schrödinger equations as a matter of fact.
I mean, the special relativistic extensions of Schrödinger equation: Klein-Gordon equation, Dirac equation, Proca equation, and so on.
What I wanted to say from these two comments is, the Schrödinger equation must be indispensable entity of the quantum physics, but it's not the everything.
Quamtum physics itself can't explain many things alone, and its unification with relativity should be unavoidable.
After the long unwanted story, short note about the cat needs to be made.
The radioactive symbol and the toxic mark were placed following the well-known story of Schrödinger's cat.
The nib also wanted to indicate the status of the cat with the image of alive left half, and dead right half.
It's the matter of "superposition."
The gist of this thought experiment resides in its interpretation.
It poses many questions regarding the notion of "observation," and diverse interpretations arose from this story.
Copenhagen interpretation and Bohr interpretation might be familiar as these two are famous.
Personally, the most intriguing one (as a story, strictly speaking) is the multiverse interpretation.
In the multiverse theory, when the observation is made, the universe is branched into two decoherent universes: one with a living cat, and the other with a dead cat.
Stories related to the Schrödinger equation never ends, and a train of ideas come.
Hence, I feel like I need to wrap up at this moment.
This post was much more focused on the physics rather than the pen, but it'd be good to read these things from time to time!
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