Turbo Pascal for Windows

A day in year 1995, somehow, I needed to take a ferry to Hong Kong Island. Before that, I went to the Star Computer Centre in Tsim Sha Tsui. I found a box of Turbo Pascal for Windows. More likely, I went there when I came back from Hong Kong Island.


WinWorld screenshot

More more likely, I went there and saw the box before going to Hong Kong Island; and then went there again to buy it when I was back.

I needed that for doing my programming homework. It cost me 299 HKD.

Throughout that school year, I did almost every exercise in my programming textbook, at the cost of my Additional Mathematics and Biology time. However, for my programming projects, I still needed to test them under Microsoft Pascal, because it was what my school computers ran.

Even during moving house in 2019, I was still not willing to throw this box away.

— Me@2022-03-02 05:20:54 PM

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2022.03.02 Wednesday (c) All rights reserved by ACHK

The particle-trajectory model

The 4 bugs, 1.13

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The common quantum mechanics “paradoxes” are induced by 4 main misunderstandings.

4.1  Each particle always has a definite identity. Wrong.

identical particles

~ some particles are identical, except having different positions

~ some particle trajectories are indistinguishable

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trajectory indistinguishability

~ particle identity is an approximate concept

— Me@2022-02-11 12:47:14 AM

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physical definition

~ define microscopic events in terms of observable physical phenomena such as the change of readings of the measuring device

~ define unobservable events in terms of observable events

— Me@2022-01-31 08:33:01 AM

4.2  Each particle always has a trajectory. Wrong.

Which trajectory has a particle travelled along” is a hindsight story.

The electron at location x_1 at time t_1 and the electron at location x_2 at a later time t_2 are actually the same particle” is also a hindsight story.

These kinds of post hoc stories do not exist when some definitions of trajectories are missing in the overall definition of the experiment setup. In such a case, we can only use a superposition state to describe the state of the physical system.

Since such a situation has never happened in a classical (or macroscopic) system, it gives a probability distribution that has never existed before.

— Me@2022-01-31 08:33:01 AM

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a trajectory story

~ a hindsight story

~ a post hoc story

reality

~ experimental data

~ observable events

story

~ an optional description of an unobservable event

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Even though the nature of a trajectory story is a hindsight story or a post hoc story, it must be based on observable events, compatible with experiment results.

— Me@2022-03-01 07:33:31 PM

— Me@2022-03-02 10:30:41 AM

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The double slit experiment (and any other experiments that have quantum effects) puts the particle-trajectory model into a stress test and breaks it. The experiment exposes the bug of the particle-trajectory model. For example, the superposition case (aka the no-detector case) cannot be explained by this model.

Another example, even if the two slits on double-slit-plate are all closed, some particles, although not many, will still “go through” the plate.

— Me@2022-02-27 09:17:23 AM

— Me@2022-03-01 11:09:24 PM

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quantum effect

~ an effect that cannot use the particle-trajectory model

~ an effect that does not have a trajectory story

— Me@2022-03-02 12:23:54 PM

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2022.03.02 Wednesday (c) All rights reserved by ACHK