Basics of Quantum Mechanics. About Basic Quantum Physics.

 Basics of Quantum Mechanics. About Basic Quantum Physics. 

By

Waseem Altaf 

We as humans experience the world of big objects, at a large scale, at the macro-level, in dimensions where laws of classical mechanics operate- for example I can either be at Qazafi stadium or Fortress stadium Lahore but not at both at one time. And if I hit a ball with a bat, it will follow one particular path but not several. And after the ball is hit it will not influence another ball in a parallel playground.

 But will the same happen if we are dealing with particles at the sub-atomic level? The answer is no! Laws which govern the behavior of sub-atomic particles fall in the realm of Quantum Mechanics. And since our brains are not evolved to imagine reality at such a microscopic level, things begin to appear extremely weird.

Imagine that you are a sub-atomic particle. In this case, you can be at Qazafi stadium and Fortress stadium at the same time. And if you have hit a ball with a bat, it can simultaneously move towards the gully, the deep mid-wicket and the long off. And hitting the ball at Qazafi stadium can also have the similar effect on a ball at Fortress stadium. Isn’t it extremely bizarre and unbelievable? Yes! But all the aforementioned are substantiated by experiments performed over several decades. Hence, Quantum Mechanics is fully supported by empirical evidence.

In Classical Mechanics if we know the velocity of a planet moving in an orbit and the time it would take to reach a point, we can also determine the distance it traveled- with “certainty.” But does the same principle of “certainty” apply when we are dealing with an electron moving in an orbit around the nucleus of an atom? No! 

We can measure the location of an electron, but not its momentum (energy) at the same time, hence it intrinsically remains "uncertain." Similarly, electrons absorb and release energy in discrete units resulting in their jumping from one orbit around the nucleus to another without inhabiting the space in between. This is called Quantum Leap.

Suppose we are throwing several balls in quick succession towards a bowler, the balls would reach him as discrete entities. But suppose we are throwing electrons towards a surface, will they also act as distinct particles? The answer is no! The electrons which are particles act as waves! But something very strange happens here.

 When the wave function of the electrons is observed through sophisticated devices, it changes into a particle as if being affected by the observer. Hence, while the electron is not observed it acts like a wave i.e. being at many positions at one time, a phenomenon called superposition. But when observed, the superposition collapses and we see the electron as a particle. It seems the electron would "know" that it is being observed. The implications of this experiment has given rise to the idea of parallel worlds and parallel universes.

Now the idea here is that we cannot determine the exact location of an electron in a wave but just the probability where it could be. Hence, it would all be about probabilities.

Therefore, while Classical Mechanics deals with certainties, Quantum Mechanics deals with probabilities! And since all the matter in the universe is made up of atoms and sub-atomic particles governed by Quantum Mechanics, we can conclude that the fundamental nature of reality is ultimately determined by chance or probability and not certainty.

Another extremely weird and bizarre phenomenon in Quantum Mechanics and one of the trickiest concepts in science is “Quantum Entanglement.” In simple words, Quantum Entanglement occurs when two particles become connected in such as way that when the property of one particle is changed, an instantaneous change in the property of the other particle occurs even if they are separated by great distances. It’s like two objects one in Lahore and the other in London communicating with each other without any physical means.

Today, the equations of Quantum Mechanics are the basis of all electronic devices- lasers, transistors, integrated circuits mobile phones, digital cameras so on and so forth. Scientists are presently working not only on super-fast Quantum Computing but also teleportation.

No doubt, without Quantum Mechanics we will be back into the 19th century, physicist Richard Feynman opined that Quantum Mechanics describes nature as absurd from the point of view of common sense. And yet it fully agrees with experiment. So I hope you can accept nature as it is-absurd!

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