AN INTRODUCTION TO QUANTUM MECHANICS (BELIEVE ME IT'S NOT THAT STRANGE)

Who says Physicists can't be cool
Here's one of the greatest minds of all
time-Richard Feynman

If you think you understand Quantum Mechanics , you don't understand Quantum Mechanics
- Richard Feynman 
Where does the word 'Quantum Mechanics' come from?
It's a made up of two words -
Qunata- Latin word for amount ; smallest packet of any physical quantity - like quanta of energy
Mechanics- Study of motion
So basically quantum mechanics is the study of the behavior of energy / matter on very small - atomic, subatomic scales.
Imagine you are trying to figure out the rules of any of your favorite game🎮 just by looking at someone playing the game. You will be making guesses right , and you will have to change your rules  on seeing something different . This is pretty much Physicists do (-Feynman)
In terms of figuring out rules, Quantum mechanics is a phenomenon that has made us reject some of the important and kind of obvious rules like -Each particle should exist at one point in a time.
Everything is boiled down to the concept of probability.


Like the discovery of fire had completely changed the way of living of early human beings , the study of the 'glow' has laid the foundation stones of a new way of understanding Physics.

Thomas Wedgewood , Charles Darwin's relative observed that all the objects in his oven , regardless of their shape , size or  nature became red at the same temperature🌡. Down the road,finding the answer to how the things glow-basically the answer to the nature of this graph     ➤

Max Planck accidentally laid the very first stones of Quantum Mechanics by quantising energy ->  E = hv ( h = planks constant ; v= frequency of radiation). From then we never looked back - there was discovery of photoelectric effect - by Einstein , Compton Effect and so on.



Then there was Schrodinger Equation and birth of concept of wavefunction 🌊- that marked the birth of Quantum Mechanics.

Imagine a scenario of shooting bullets through two doors. After a while we will get two bunches of particles.
Now , let's turn it down to microscopic level and try it with electrons and turn the doors to tiny openings called slits. Now let's shoot them by opening one door at a time and , we get our bunched pattern.

Bunched Pattern
(Trishula like thing you see here is the symbol of wavefunction)

Common sense says , when both the doors are open and you shoot the electron through one hole , it should not affect the bunched pattern. Each particle should go through one door and should not care about whether the other door is open or not , but no , quantum mechanics falsifies both of them.
Even when you shoot a single electron through a slit keeping both slits open , what you get is an Interference Pattern🤯

electrons passing through slits one by one

this is what we get -an interference pattern

The interference pattern gets distorted once we know through which door the particle passes through.
Quantum mechanics provides answer to this by introducing that every object exists in all the states together(superposition) and it's the act of measurement that actually makes the particle select one of the states and we observe it(i.e. wavefunction collapse).

So why didn't you observe interference with large particles even when you didn't place any detector ? -🧐 That's because the wavefunction for them has already be collapsed by atmospheric interaction. All the air around them , and other environmental factors acted like nature's detectors to collapse the 🌊 wavefunction.

 Actually it's like everything behaves in a spooky way, i.e. everything is probabilistic  until it's observed. 

But it raises many other psychologically uncomfortable queries-
Does a particle passing through a slit splits into two ?🔨
Every time we measure a trespass of the particle , the pattern vanishes - so does the universe care about being observed and why ?
Do we live in multiverses ; 🤯where each act of probability has a different timeline?


Many of them are still a mystery and answer to these questions makes the interpretation quantum physics even more weird. But that doesn't mean that we should stop knowing the fundamental nature of reality 💫
Always remember - "Universe🌠 is under no obligation to make sense to us"


references-
Image credit- Modern Physics by -Serway/ Mosses/ Moyer (blackbody radiation diagram and bunched pattern)
electron interference(left image)-Wikipedia
Feynman-valdas.blog
links- https://www.youtube.com/user/LookingGlassUniverse