Quantum Theory Overview - how smallest particles behave in the universe.
- 1. Quantum Theory It is a rule of science that explains how very small things behave such as atoms, electrons, and light particles. For Example : Suppose we have a gift box and we don’t know what’s inside. It could contain a smartwatch or a phone or something else. Until I open the box, for me all the possibilities exist together. But as soon as I open the box one thing appears in front of me - say, a smartwatch. Now the possibility of having a watch in the box becomes a reality and all other possibilities disappear. So in the quantum world something similar happens. until a tiny piece is observed, it remains in every possible state, just like a gift box that could contain a watch as well as a phone both together. Now you may wonder how this is related to tiny pieces. There are small tiny pieces inside an atom, like electrons. This theory was developed to explain the behaviour of those electrons i.e strange behaviour. Just like a watch can be inside a gift box and a phone, similarly an electron can also be at multiple places at once - until we observe it. This kind of behaviour appears only in tiny particles, and not in our daily life objects like a cricket ball or human body because such objects are too big for such unusual effects to occur. Let’s take another example : Imagine there is a small magnetic chip on a table, moving so fast that your eyes can’t see where it really is. It seems to be everywhere at once. But the moment you pause the motion to look at it,the chip appears at one exact spot. So small things behave the same way. Until we observe them, they settle into one exact place. Quantum Mechanics ? It is a rulebook of science that explains how the smallest things behave. It is made for those objects which we can never see directly. So what do they do? It tells us where these small bits
- 2. might be, how much energy it is using, when it will go from one state to another. But none of these things are 100% confirmed - It only tells us the probability of what can happen by what chance. It is a system that explains the rules of the microscopic world - where things are not fixed, but full of possibilities. To study these possibilities, scientists use a concept called the wave idea. Wave Function This is a way of thinking that shows where a small bit might be and how likely it is to be there. Imagine you are outside a house and hearing music. It’s loud near the window, quieter near the back wall. Based on volume, you guess the speaker is near the window. Just like that scientists look at these chances - louder means higher chance the tiny piece is there. So the math of probability - used to describe these chances - is what the function represents. This function contains complete information about where the piece could be. Until you observe it, it exists in every possible location at once. The moment you observe it, the function collapses - and the tiny piece appears in just one real position. Example: Think of the playlist of all songs But the moment you hit "play”, only one song plays - that's the Collapse Meaning : A math tool that shows where a subatomic object might be Purpose : To predict the probability of position, speed, and behavior of subatomic objects. Before looking : They exist in all possible states at once. Once we check : They settle into one reality. It is helping in real life too : ● MRI Scans in Hospitals : Doctors use MRI machines to see inside the body. These machines use such functions to understand how atoms inside us react and give signals.
- 3. ● Atomic Clocks Quantum Cryptography It is a technique that uses a wave function to send data securely. As long as the message is in its original form, everything is fine. But if someone tries to read the message in between, the wave function collapses - and the message either changes or disappears. This immediately reveals if someone has tried to hack that message. This tells us that what we see is not the truth, but the whole truth - the real story is hidden behind it. What is Quantum Physics? It tells us how everything works at the smallest level - i.e. In a world smaller than atoms, Most of the things around us are not visible to us - like small bits, invisible forces that work without being seen. For large objects like apples, planets, Classical Physics works correctly, but when we dive into smaller spaces, those old rules fail. That’s where this new idea starts playing a role. This is a new rule book for the small world. Imagine you pressed a button on a vending machine. Suppose you press the A1 button in which you get chips which are predictable. This is Normal Physics. But if the same machine followed quantum rules, then pressing the same button wouldn’t always give you chips - Sometimes you would get chocolate, sometimes nothing at all. That’s why the world of small tiny pieces works on probability and not on certainty. The reactions that happen in your brain like thoughts, mood swings, etc. can also be influenced at quantum level.
- 4. Quantum Tunneling In the normal world, if there is a wall and something has less energy, then it stops. But in the quantum world, a small piece sometimes crosses the wall without breaking it because it behaves like a wave. Imagine, a small ant is in a locked room. The door is closed. In the normal world, it cannot come out. But in this strange world, the ant comes out without opening the door. As if it has teleported. Another concept of quantum physics is : Quantum Entanglement This means that the two particles are strongly connected to each other. If something changes in one, then a change also takes place in the other immediately - no matter how far away it is. That is, the effect of one affects the other instantly - without taking any time. If two split a small light particle into two, then they get linked to each other. If one spins in one direction, the other instantly moves the opposite way - no matter how far they are. It’s not magic, it’s Quantum entanglement. It’s like giving two friends a special pair of gloves - one red and one blue - and sending them to opposite ends of the world. As soon as one opens the box and finds the red glove,they instantly know the other has a blue one. But here, this connection happens instantly - even if the particles are galaxies apart. This is not just imagination. In the world of extremely small things, such connections are real, and scientists have tested them many times. It’s one of the biggest mysteries of nature - and it’s already being used in quantum technology. Quantum physics may be invisible to our eyes , but it shapes the visible world. The deeper we go into it, the more we realize - the universe is full of surprises we’ve only just begun to understand.
- 5. Planck’s Quantum Theory ? It says that energy is not shared or received in a smooth, flowing way. Instead, it comes in small, fixed bundles called quanta — just like how you can't receive half a coin in a video game, energy also cannot be taken in half or random amounts. Nature only gives energy in whole packets. Example : Think of a vending machine. It only works if you insert the exact amount — say, 10. If you put ₹ 9, nothing happens. That’s how ₹ atoms work too. They don’t react to random energy; they need the exact amount to make a change. According to the classical laws of science, when an object is heated it should emit every type of light, especially UV light, in large quantities. But this did not match with what we saw in real life. The calculations and the reality didn’t match. The theory was failing. For Example : When an iron rod is heated it first glows red, then orange and then white. But according to the old theory, ultraviolet light should also be released - and in unlimited quantities. This was not physically possible. If that really happened , everything would burn due to that match energy. Then Plank came up with a new idea. He said that energy is not released continuously but in small packets and when he applied his formula, everything matched perfectly. Formula : E = h * f E : Energy contained in one bit h - It is planck's constant value f - how fast the wave is moving This formula tells us that faster waves carry more energy. Just like
- 6. Slow music has less energy. Fast, high - pitched sound has more energy. Similarly light and particles also carry energy depending on their frequency. Quantum Theory of Light Light is a part of our daily life - from sunshine in the morning to the glow of a lamp at night. We’re surrounded by the light all the time, but rarely stop to wonder what it really is. This question led to the creation of the light’s theory. Imagine you are standing in a light rain.The drops feel gentle and flow over you - just like a wave. But now think of a tiny ball lightly tapping your hand - it hits with impact. Light can act in two surprising ways.; it spreads softly like a wave, or it hits with force like a tiny energy bullet, depending on how you observe it. Light helps in many things. It makes devices work, sends messages through fibre cables, and helps scan barcodes in shops. These things help us know how light works and how we use it in daily life — like in glasses, mirrors, and cameras. Examples : 1. Tv Remote : When you press a button on your TV remote, it doesn’t shout the command. It silently sends out a tiny burst of invisible infrared light - and your TV listens. 2. Barcode Scanners : At the checkout counter, light doesn't just shine - it reads. That red scanner reads the barcode and instantly figures out what item you’re buying. The theory is not just a chapter in physics; it’s a never-ending story that still lights the path of discovery for future generations to follow and explore with curiosity. Future of Quantum Theory :
- 7. In the future, it is expected to change the world in powerful ways. Scientists are building superfast computers that will solve problems much faster than today’s machines. Quantum communication may allow perfectly secure data transfer. This new technology can also help in medicine, artificial intelligence, and even space research. The strange behavior of tiny pieces could soon lead to big changes in our daily lives.