Archive for the ‘Science’ Category

The Quantum World

October 3, 2018

The Quantum World

New Scientist Instant Expert Series, Nicholas Brealey Publishing, 2017

 

I was first introduced to Quantum Mechanics in 1960s. I did not have any future opportunity to get more familiar with the subject. My interest in this subject was revived recently by two factors:
a) I happen to read a book, titled ‘Biology of belief’ – by Bruce H Lipton, where the author invokes Quantum theory for explaining some of the biological behaviour of cells in our body,
b) I was intrigued by an experience of a Quantum Maths professor of Yale University had with Poojya Sri Kanchi Paramacharya, as reported in the following link.
(https://m.facebook.com/JagadguruSriMahaPeriyava/posts/1652739764815897)
Paramacharya apparently quoted a verse from rig veda, which explains the difference between Positive and Negative approaches to Quantum Theory! (Can someone get the exact text of this verse?)
I started reading this book – The Quantum World (New Scientist Instant Expert Series, Nicholas Brealey Publishing, 2017) for getting more insight into the processes of Quantum Mechanics. It is still not black and white, like Newtonian Mechanics. It is still sort of grey, with lot of holes in between.
This quantum revolution was started by a German physicist Max Planck in 1900, when he was researching black body radiation. He was led to believe, by his mathematical calculations, that the energy from blackbody was not radiated continuously, but in discrete little packages, which he called as ‘Quanta’. This seed for Quantum mechanics sprouted further by the efforts of Albert Einstein. He was researching photoelectric effect, when he found that, electrons were released from metal by the light of certain frequencies, regardless of its intensity. He proposed in his paper in 1905, that light energy also is made up of stream of little ‘atoms’, he called as ‘photons’. This was supported by the research of Niels Bohr of Denmark. He proposed that in the atoms, electrons are orbiting around the nucleus in several discrete orbits and when they jump between two orbits, light is emitted in discrete packets known as ‘photons’. This was later proved by calculation of energy difference between the two orbits and comparing the same with the energy of the photon emitted. Random nature of wave/packet of light, was further demonstrated by the behaviour of light when it hits the boundary of another medium, like glass. Randomly some photons of light get reflected and some of them get through. It was left to French physicist Louis De Broglie to come out with a revolutionary idea. Building on Einstein’s photon equations, he proposed in 1923, that electron ‘particles’ also behave as ‘waves’, just as, ‘waves’ behave like photon ‘particles’. Soon it was proved to be true, when electrons from helium atom were beamed through a grating (slits), it created interference pattern on the other side, just like waves of light or water. At this point in history, Wave-Particle duality became an accepted reality and Quantum Theory got firmly established.
“The pioneers of Quantum Mechanics were not entirely comfortable with the weirdness they discovered”. Niels Bohr himself was quoted as saying “Anyone who is not shocked by quantum theory has not understood it”. As late as in 1958, he is further quoted as saying to another quantum scientist, “we are all agreed that your theory is crazy. The question that divides us is, whether it is crazy enough to have a chance of being correct”
I am not sure whether I have understood ‘enough’ to be ‘sufficiently’ shocked!!! However I found the following narrations very interesting, which I want to share with my readers.
1. This is about how a chlorophyll molecule of a plant leaf behaves as a receptor of energy and transports the same to an action centre where this energy is converted into food and nutrition. Herein we can see how the energy in the form of EM waves in the visible spectrum is converted into a particle which again splits into innumerable number of waves and travels with speeds close to light to the actions centre with minimum loss of energy. The process is described in the book as below:
“The first step in photosynthesis is the capture of a photon of light by an electron of a magnesium atom, of a molecule of chlorophyll pigment. The extra energy causes the electron to vibrate forming a particle called ‘exciton’.”  This should travel to a reaction centre where this light energy will be transformed into chemical energy, thus forming flowers and vegetables. This travel should be fast with least resistance, through the forest of Chlorophyll molecules, in a way that the energy loss is minimal. “Yet measurements show that the exciton transport has the highest efficiency close to 100%”. Further experiments showed that exciton was not taking one particular route; … “it was taking all possible routes to the reaction centre as quantum waves. This was the first direct evidence that, at its heart, photosynthesis is a quantum mechanical process.”
2. Second one is about a bird species of Robin which flies thousands of miles down south to escape harsh winters of northern hemisphere. Its two eyes, when hit with sun’s rays converts them into an electrical dipole of –ve and +ve charges. This bird uses this dipole interaction with earth’s magnetic axis as a compass and gets the direction of forward return flight correctly.
“In 2000 Thorsten Ritz of the University of California came up with the idea that it might depend on a peculiar feature of quantum entanglement. When two entangled particles are electrically charged, they can detect the angle between them, and the earth’s magnetic field. As a test and verification of this theory, this quantum compass was found to get disturbed by high frequency radio waves, as expected.”
Nowadays, we hear many reports, of birds losing their ways, because of their navigation system getting disturbed by radiations from cell phone towers.
3. Third one is about teleporting of matter from one place to another at the speed of light. There are experiments attempted with partial success in which smaller molecules of a matter was converted to waves of energy and recd afar with the speed of light with subsequent re-assembly into matter again.
“Enzymes are the engines of life. They are incredible catalysts that can speed up chemical reactions by a factor of 10²º.” (i.e) 30 billion times the speed of light. “Enzymes gain their huge chemical acceleration by manipulating the quantum mechanical nature of matter, employing a process called quantum tunnelling. This is where a particle can travel through a seemingly impenetrable barrier using its wave properties, essentially dematerialising from one point in space, and materialising in another, without visiting any of the in-between places.”
When I was going through the book, I felt the subject of Quantum Theory is more Metaphysics than Physics. I am sure I am not alone in feeling thus.
Max Planck, the founder of quantum theory, was deeply religious and in 1937 he wrote: ‘Both religion and science need for their activities, the belief in God.’
De Broglie feels ‘Quantum Theory is incomplete; we are lacking some hidden properties and, if we knew them, it would make sense of everything.’
Quantum Theory works well with small particles. Once things get larger they lose their quantum properties. This process is called De-coherence. From this point, Newton’s classical mechanics come into effect. When things get even larger to the level of universe then Einstein’s gravitational principle and his Theory of Relativity takes over.
Interference pattern were observed even with molecules composed of hundreds of atoms, but as they get more massive, this quantum property of superposition get short lived. Is this due to gravitational force taking over?
Quantum Theory rules the atomic scale; Theory of Relativity rules across the cosmos. If physicists can meld both the above theories together, we may hope for the evolution of a ‘Theory of Everything’ that will show how whole universe works at fundamental level.
Till such time several theories are being put forth which is quite intimidating as seen below.
What happened before ‘Big Bang’? Some cosmologists suggest that our universe rose from the ashes of an earlier cosmos which collapsed in a ‘Big Crunch’. For Hindus it may sound like a Pralaya kala or end of a Yuga.
Another take on the implications of quantum mechanics talks of Many-Worlds, into which the universe splits each time you make a measurement of a quantum particle. Our universe itself could be a part of a multitude of universes, some of them arising out of exponential expansion of space-time. The many-world interpretation of quantum mechanics also involves the existence countless universes, parallel to our own, and interacting to generate quantum phenomena.

 

I will end this blog by quoting the following form the book:
“Put simply our concepts Reality, Relativity, Causality, Free-will, Space and Time, all of them cannot be right at the same time. But which ones are wrong?”
“Obtaining a solid theoretical foundation for quantum theory has eluded scientists for more than century. But the above six principles might be all it takes to make sense of it – and lead us to a Theory of Everything.”
Does a ‘Theory of Everything’ already exist in our Hindu Vedas? But even if it exists, who can read it, understand and interpret? Longer it takes less is the possibility.

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