Quantum theory is modern physics which describes the behavior of sub-atomic particles. It was established by two great scientists , namely Albert Einstein and Max Planck. Max Planck showed that energy of a process is quantized. Any periodic process can carry energy that is integer multiple of hv [ its frequency times Planck’s constant h]. Einstein later showed that light is composed of energy packets called photon. Planck’s theory was applied by Bohr inside atom and a successful atomic model was created. Any electron in its quantum orbit can emit or absorb light of certain frequency and jump from it. Later Schrodinger was very frustrated by this weird quantum jumping of electron.
Luis De Broglie hypothesized that sub-atomic particles act like wave. He also showed exact relationship between matter wave and particle’s momentum which is mass times velocity. Every elementary particle like electron is a wave and every wave is a particle of some sort. In classical mechanics this effect is negligible due to short wavelength associated with the massive objects. In quantum world a tiny particle shows more waviness.
The last revolution was the Schrodinger’s wave equation which describes the wave function of particle in terms of probability. Schrodinger’s equation successfully explains Hydrogen and other simple atoms and shows how bizarre an atom looks. An electron does not exist in a definite place but it has only some probability to be in some place at a time. Electrons tend to exist at some place. This was the consequence of Heisenberg’s uncertainty principle. What we call electron is really a collection of radiations which try to be localized at some point in space.
Earlier Heisenberg stated his uncertainty principle which shocked everyone. In quantum world nothing has definite position and momenta. If we measure position more precisely the momentum becomes more uncertain and vice versa. We can not know both of them simultaneously with arbitrary precision. The nature has set a limit to our knowledge about it.
Secret of creation :
The beginning of our universe was a quantum event. General theory of relativity fails at this event when universe was very tiny and dense. Whenever small object is concerned quantum mechanics is necessary to describe its behavior. Spacetime is smooth and continuous on large scale. All the stars , galaxies and planets exist in a continuous spacetime manifold. What if spacetime may not be smooth in quantum level? It might have holes and gaps like the pretzels and doughnuts. The secret of the universe can only be traced in quantum level where everything is governed by chance and discontinuity. We do not know , in advance , when an electron will jump from one orbit to another. We only know if they do they will emit a photon of specific wavelength to go into another orbit. Nature, so it seems, is full of revolutionary occurrences , whose cause is never known. All we can predict is the probability of an outcome : like the chance of getting a six by throwing a six headed dice.
It is hard to reconcile quantum mechanics into the framework of general theory of relativity. There arise many mathematical problems while doing that. Quantum mechanics and general relativity become very antagonistic to each other. They do not shake hands at all. Quantum mechanics certainly holds the key to unlocking secrets of the universe. Three fundamental forces can be explained by the principles of quantum mechanics. Quantum mechanics has changed the view of our world completely when it comes to how these fundamental forces work. Electromagnetic force is the exchange of photons between two charge particles. Similarly strong nuclear and weak nuclear forces are carried by other sub-atomic particles like gluons and boson. Electromagnetic force is long range while strong and weak nuclear forces are short range where strong magnetic has the special property that when the distance in the nucleus increase the intensity of the force also increase. This has to do with another weird phenomena that quantum theory describes. This phenomena is quantum fluctuation.
Vacuum is not truly empty. It is full of activities dues to random generation of particle -antiparticle pairs all the time. This is also a consequence of Heisenberg’s uncertainty principle. The energy of vacuum can not be zero because in context of quantum mechanics zero is a precise number. Electron and positron pair can come into existence out of nothing. So vacuum is not truly passive . It is always seething with virtual particles and energy.
The greatest mystery is probably quantum entanglement which states that information can travel faster than light, which is also known as the spooky action at a distance. Einstein was deeply worried by this fact and unfortunately he could never come up with any valid counter argument to refute this. An electron when entangled can communicate instantly with its entangled pair over a larger distance; probably at the other side of the universe. Secret of creation or secrets of the universe deeply lies at the heart of quantum mechanics. I like to rephrase Nikola Tesla : If you want to find the secret of the universe think in terms of vibration , energy and frequency. In quantum mechanics all particles are vibrations or oscillations in their corresponding quantum field. Oscillation in the quantum field creates energy and that energy, in turns, create particles according to Einstein’s famous energy mass equivalence formula (E=mc^2). Einstein was a strong opponent of quantum theory throughout his whole life.
Theory of relativity throws a little light on the secrets of creation. It has some philosophical consequences and some applications can be found in causal theory of perception and analysis of mind. Mind and matter are not very different from relativistic point of view. What we call mind is certain group of events connected with specific relation. These are all the events that have space-like interval between them so any other observer can judge any of two to be simultaneous. What we call matter is also a group of time-like events. What happens when we look into another people’s eye are the events connected with one light rays. These events has light-like or zero interval. Quantum theory might be more fundamental than theory of relativity but relativity is able to describe four fundamental forces. Special theory of relativity describes three forces whereas general relativity describes one force.
Quantum theory basics :
The most important basics of quantum theory may be coherence and de-coherence. In an isolated quantum system there is quantum coherence. That is , the states remain uniform and in phase. Schrodinger’s equation describes a quantum system as an smeared out probability of finding a particle like electron in space. These probability wave evolves through time. Schrodinger’s equation also states that particle can exist at different places at the same time , which is known as quantum superposition. That is what we better know as the Schrodinger’s cat. Schrodinger cat is alive and dead at the same time unless we look at it. That means, there is coherence in the system unless we observe any such quantum system. After the system is observed, the system collapsed to one of the states of the system. This can be explained as the particular state of the Schrodinger cat , which can either be dead or alive after box is opened. Decoherence is the act of observation which collapses the system. Due to decoherence the quantum system no longer remains coherence and this happens through the interaction with the environment.
Common sense and quantum theory: