Quantum World

The quantum world that is the world of infinitesimally small…the world of electrons and Photons, is pretty different from what we observe in daily life. The reality at quantum dimensions is so weird and understanding that great physicists of the status of Einstein, Niels Bohr, Richard Feynman have failed to understand it fully. Niels Bohr quipped, “If anybody says he can think about quantum physics without getting giddy, that only shows that he has not understood the first thing about it”. The problem with the world at quantum level is that the quantum particles seems to have no regard for the rules of  classical mechanics framed by Newton and others that seems to so well describe our observable universe.

For example

1.     At quantum levels you can create reality by simply looking at it.

2.     A quantum particle can occupy more than one place or take more than one path at the same time. This simultaneous coexistence of all possibilities is known as coherent superposition or quantum coherence.

3.     Quantum entanglement: As shown by Non locality experiment that if we send twin photons that were joined earlier to different sectors of space, any action performed upon one instantaneously affects the other as if they remained forever bound in spite of their spatial separation.

In Quantum world a quantum particle actually exists as a wave function with the probability of finding it extending till the end of universe but with a high probability of finding it at one particular space. This description of quantum particle actually arises from the famous uncertainty principle of Heisenberg who stated that it is impossible to measure the position and velocity of a quantum particle accurately beyond a certain fixed level of accuracy defined by his equation. This impossibility is not due to the fault of measuring instruments but is inherent characteristics of quantum world. That the position of quantum particle is defined in terms of probability led Einstein to utter: “God Does Not Play Dice”. However as soon as a quantum particle is observed by a conscious agent they collapse from their wavy nature to reality at a particular position.

For example let us consider that you are an electron seated in a chair. But in quantum world you are actually a wave spread over the entire universe with high probability of finding in your chair. You will remain in that state until and unless a conscious agent looks upon and collapses you into reality seated in the chair. This may sound like the staff of science fiction but the postulates and predictions of quantum mechanics have been proved through numerous experiments like EPR and Young’s Double Slit Experiment.

                                            THE EPR EXPERIMENT 

Now the question is what is consciousness (click on the link to know more about consciousness)? Scientists are too in debate over this question and we will deal with it in our next article.

Let us return again to uncertainty principle of Heisenberg. The uncertainty principle can also be stated in terms of energy and time. It states that if time is stretched enough and we look at very very tiny interval of time while trying to find out about the energy of a certain small volume of space we would be so uncertain about its energy content that a particle may pop out of existence out of nothingness provided it vanishes as soon as it appeared. To show you how this could happen let me tell you a small story.

Around 1928 Physics was suffering from another big problem. The two most important theorems of physics did not agree with each other. On the one hand you had Einstein’s special theory of relativity that described the description of particles moving at a speed close to the speed of light encapsulated in the beautiful equation E=MC² and on the other hand Planks discovery of quantum and the revolution that followed describing the bizarre rules of very very small. Problems arose when trying to describe the behavior of particles that were small enough for quantum rules to be applies and moving fast enough for Einstein’s special theory of relativity to be applied, (especially the behavior of electron). If this theory could not be married it meant that one of them had to be wrong.

At this critical moment Paul Dirac; a brilliant scientist came up with a very elegant description of election that helped to marry the Einstein’s special theory of relativity with plank’s quantum mechanics.

This elegant equation is known as the Dirac equation. In his description of electron Dirac was forced to use a set of four equations represented by the symbol γ.

                       

While the first to equations were quite familiar and referred to the behavior of electron as observed in the laboratory. The next two pair were suggesting to a type of electron never before observed. In some way just like the electron yet very very different. It came to be known as the anti-electron. Dirac realized that if the things and anti-things ever meet each other they would instantly annihilate converting all their mass into energy.

Now here was the answer to the riddle of empty space. Heisenberg had suggested that matter could pop into existence from empty space for very very small amount of time. Dirac provided the mechanism how this could happen. So actually whenever a matter particle pops into existence from empty space so does its anti particle and then they quickly fall back upon each other and annihilate.

Strange as it may seem just like a compulsive credit card addict, pairs of particles and antiparticles constantly borrow energy from space to pop into existence before annihilating again and returning back the energy. Thus what may seem as vacuum is constantly seething with this activity which is known as quantum fluctuations. But as soon there is sufficient energy made available by any source, stable particles are able to emerge and have a ‘real’ existence in the world.

Now you might be wondering why am I discussing so much about nothingness and quantum world?! Well for the curious mind here is the answer…Wherever you see in the observable universe including sun, moon; stars, you and I all have come out of this vacuum. So to understand and get the big picture you have to understand the small…. Om tat sat