Quantum Theory:
Physicist Max Plank, was trying to answer the Question, "Why glowing body changes color from red to orange and than to blue as its temperature increases". He came up with a solution and presented it to German Physical Society in 1900. The presented theory he called "Quantum Theory".
In order to solve this he made an assumption that energy existed in individual units (like matter) rather than constant electromagnetic waves. He called this individual unit as "quanta".
According to Planck's equation " E = hv " where E is the energy of electromagnetic waves, h is Planck's constant (it relates the energy of a quantum photon or quanta of an electromagnetic radiation with the frequency of that radiation) and v is the frequency of that radiation.
He made and assumption, gave an equation, this equation explains the above phenomenon quite well, in a way that when temperature changes the energy spectrum occupy a different discrete color spectrum.
This was the beginning of a totally new way of looking at the universe. Since then every great scientist contributed to our recent understanding of Quantum Theory.
He made and assumption, gave an equation, this equation explains the above phenomenon quite well, in a way that when temperature changes the energy spectrum occupy a different discrete color spectrum.
This was the beginning of a totally new way of looking at the universe. Since then every great scientist contributed to our recent understanding of Quantum Theory.
Some important developments in Theory:
In 1900 Max Planck, made an assumption that energy is composed of individual units or "quanta" just like matter.
In 1905 Albert Einstein, suggested that not just energy of an electromagnetic radiation but also the radiation itself is quantized.
In 1924 Louis de Broglie, proposed that there is no difference in makeup and behavior between energy and matter. This principle came to known as, "The principle of wave-particle duality".
In 1927 Werner Heisenberg, proposed, "Uncertainty Principle" which claims it is impossible to accurately calculate two complementary values of a subatomic particle (i.e. position and momentum). The statement is contrary to concepts of classical physics.
Famous Quantum Experiment:
Under the context of above developments, we have a very famous experiment, "Double Slit Experiment".
If we have an observing screen and an electron gun, between these two we place a double slit wall. Now when we fire electrons on the screen, we should get two parallel lines right behind those two slits, that's how matter behaves. But what we observe it results are totally opposite, instead of two parallel lines we get an interference pattern on the screen (as if electron were a wave not a particle).
The only possible explanation could be that each electron is passing trough both slits, but when we try to test it and place a detector in front of each slit, we observe that electron passes through only and only one slit and this time we do not see an interference pattern just two parallel lines. It seems that electron knows when it is being watched.
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| Double Slit Experiment |
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| Wave interference property |
Two Major Interpretations:
Quantum Theory made every one think again about there universe and many different interpretations came out from different minds. Among other two interpretations are most accepted these are Copenhagen Interpretation and Many Worlds Interpretation.
Copenhagen Interpretation:
Neil Bohr came up with Copenhagen Interpretation, it claims that a particle is whatever it is measured to be (for example a wave or a particle). But it can not be assumed that a particle has some specific properties or even it exists until we measure it. In short Neil Bohr said that, "Objective Reality does not exist".
This principle is known as, "The Superposition Principle".
According to this principle an object is in its all possible states and that object stays in all those states until we try to measure that object.
Many Worlds Interpretation:
Second interpretation Many Worlds or (Multi-verse Theory) was first presented by Hugh Evert III in 1957, and it claims as soon as a potential exists for any object to be in any state the universe of that object operates it into a series of parallel universes equal o the number of possible states of that object, with each universe having a unique state of that object. We live in a multi-verse and all universes communicate and interact in a specific way and also affect each other in some manner.
In short, reality is all possible combinations you can have and the one you see is right now associated to your universe because you are trying to observe it.
Conclusion:
Quantum Theory is the debate of the century and the very basic assumption of Max Planck that matter and energy have same makeup and that there is no difference in their behavior was a huge break through in Physics. Quantum theory contradicted classical physics. New and better experiments are being performed to explain this theory better and better. Quantum Theory explains behavior of subatomic particles where forces like strong force and weak force are applied, but it completely ignores gravitational force because the gravitational force at subatomic level is One Hundred Trillion Trillion Trillion times less strong then Strong Force i.e. if Strong Force at proton level is 1 then gravity's string will be only 10^-38, so Quantum Theory ignores gravitational effects. Work in new fields like Quantum Computing and Quantum Chemistry is being done.
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