Literary, Bangladesh, International, Technical, Life as it is, Cultural, Advanced science

Tagore’s philosophical views and Quantum Mechanics

Rabindranath Tagore (actual Bengali name: Rabindranath Thakur) (1861–1941), the great Indian philosopher, a Bengali poet and a polymath, who received Nobel Prize for Literature in 1913, lived during a transition period of Indian history in general and the Bengali culture in particular, when physics also went through revolutionary changes. Albert Einstein (1879–1955), the most prominent physicist of the 20th century, was the pioneer of modern physics, who produced theories which advanced physics to unprecedented levels. Although Einstein produced the ‘the principle of photoelectric effect’ for which he received the Nobel Prize for physics in 1921 and which was pivotal to the advent of quantum mechanics, he could not fully reconcile with the multifarious implications of quantum mechanics. The two stalwarts of the first half of the 20th century met a number of times from 1926 onwards. When Tagore visited continental Europe and then America in 1930, they met at least four times in Berlin and New York. The meeting at Einstein’s summer villa outside Berlin was of particular interest when they exchanged views and philosophical ideas extensively. During that meeting – poignantly described by Dmitri Marianoff, a journalist in the New York Times, as being between ‘Tagore, the poet with the head of a thinker, and Einstein, the thinker with the head of a poet’ – the two exchanged views on the reality of nature.

Einstein held the view that the world and, for that matter, the whole universe, is there independent of humanity. Tagore held the view that the world is a human world and hence without humanity, the world is irrelevant and non-existent. Einstein persisted and queried that aren’t beauty and truth absolute and independent of man? Tagore disagreed and said that truth is realised through man and without man it does not exist. The whole conversation between these two giants was absolutely fascinating – it brought out the mindset of a scientist seeking out nature as it exists and that of a poet observing nature through the eyes and minds of human beings.

Einstein’s commitment to the reality of nature was absolute, and that absolutism brought him into conflict with the quantum reality proposed by Niels Bohr, Werner Heisenberg and others. Einstein believed in the existence of causal, observer-independent reality; whereas quantum mechanics considers reality dependent on the act of observation. Bohr/Heisenberg proposed that an atomic particle like an electron is there only when it is observed. If it is not observed, it is not there; it could be anywhere only to be described by quantum functional description. But Einstein would not accept that. He retorted by saying that the moon is there in the sky whether you observe it or not. Quantum mechanics states that an entity having unobserved presence cannot be claimed to be present with absolute certainty (with the probability of 1). Quantum mechanics tell us that the observer and the observed are entwined. The reality is not pre-ordained; reality is what is observed.

In 1928, Tagore received Arnold Sommerfeld, professor of theoretical physics at the university of Munich and a pioneer of atomic spectra, at Shantiniketan, West Bengal. Sommerfeld stated, “Tagore is to India what Goethe (pronounced as Görta) is to Germany”. Sommerfeld’s student Werner Heisenberg visited India the following year.

Heisenberg was one of the principal architects of quantum mechanics and his ‘uncertainty principle’ is the cornerstone of quantum mechanics. During the 1920s, he, along with Niels Bohr and others, produced what is now known as the ‘Copenhagen Interpretation of quantum mechanics’, where multiple existence of an atomic particle at different locations with superposition of quantum states was considered to be the reality of nature.

Although quantum mechanics had enormous success and explained various physical phenomena, which classical physics was incapable of explaining, the conflict with Einstein on quantum mechanical fundamental assumptions of probabilistic description was deep rooted. Einstein considered quantum mechanics as an incomplete description of nature.

In 1929, when Heisenberg undertook a lecture tour around the world, he came to India. On 4 October 1929, he visited the University of Calcutta and in the afternoon, he visited Tagore. In fact, he was taken to Tagore’s house at Jorasanko by the scientist Debendra Mohan Bose, a nephew of Jagadish Chandra Bose, and they had a number of conversations over the next few days. Heisenberg was very much impressed by Tagore’s philosophical views. Fritjof Capra in his book Uncommon Wisdom wrote,:

“In 1929 Heisenberg spent some time in India as the guest of the celebrated Indian poet Rabindranath Tagore, with whom he had long conversations about science and Indian philosophy. The introduction to Indian thought brought Heisenberg great comfort. He began to see that the recognition of relativity, interconnectedness and impermanence as fundamental aspects of physical reality, which had been so difficult for himself and his fellow physicists, was the very basis of the Indian spiritual traditions.”

Heisenberg said, “After these conversations, some of the ideas that had seemed so crazy suddenly made much more sense. That was great help for me.”

Heisenberg’s comfort was to be seen in the context of a great intellectual battle that had been raging at that time between Einstein and Bohr/Heisenberg on the reality of nature. Indian mysticism or more accurately, Tagore’s interpretation of Oriental (Brahma) philosophy, giving a support to modern physics and quantum theory, was undoubtedly a great comfort to Heisenberg. No wonder, Heisenberg even said after their conversations that Tagore reminded him of a prophet of the old days!

Tagore’s philosophy of viewing the world with human eyes may seem to conflict with Einstein’s observer-independent reality, but these are two perspectives of the reality. Tagore’s view of reality resonates very well with the quantum philosophy of observer-dependent reality.

Dr A Rahman is an author and a columnist

Advanced science, Astrophysics, Bangladesh, Cultural, International, Life as it is, Literary, Religious, Travel

Einstein’s hand written letters are intensely sought after

Albert Einstein, the most famous scientist of the 20th century and the most iconic figure of a physicist, had lost not an iota of world’s admiration and fascination even after 65 years of his death. The world, it seems, is keen to grab whatever bits and pieces it can get bearing Einstein’s name or attachments at any price.

This was evident from the recent auction of a single-page hand written letter by Einstein in German to a Polish-American physicist Ludwik Silberstein by a Boston based RR Auction house. The interest in this hand written letter of Einstein was so intense that the auction started on the internet on 13th of May, 2021 with lots of internet bidders and concluded on 20th of May, 2021 when two anonymous final bidders slogged it out in a desperate bid to procure it and eventually it was sold for $1.2million (£850,000).

This Einstein’s letter written on 26th October 1946 on the Princeton University letterhead addressed to Ludwik Silberstein, who was a severe critic of Einstein, said cryptically, “Your question can be answered from the E=mc2 formula, without any erudition.” The letter was kept in Silberstein’s personal archives and nearly 70 years later his descendants retrieved it recently and sold it in the auction.

The letter in itself contained no new material of scientific or technical interest that may stir intense interest to anybody. The novelty was purely of Einstein’s hand-written element. In fact, it contained a somewhat incomplete mass-energy equivalence equation, which Einstein produced some 40 years earlier (before he wrote the letter) in 1905 and published in the Annalen der Physik, world’s leading physics journal at that time. The original equation that he produced was

                                    E = m c2 / √(1 – q2/c2

where E is the energy, m is the mass of a body when at rest,

            q is the speed of the body and c is the speed of light.

If the body is at rest, q is 0 and so the term within the square root is 1 and hence the equation becomes E = m c2. This is what Einstein communicated to Silberstein in his letter. If, on the other hand, the body happens to travel at the speed of light (most unlikely) meaning q = c, then the term within the bracket would become 0 and the energy becomes infinite. This indicates that nothing can travel at or above the speed of light.

A photo below where the full mass-energy equivalence equation that Einstein produced in 1905 is shown. This photo was taken by the author of this article when he visited Einstein’s apartment in Bern, Switzerland, which is now a museum, in 2017. At the top part of the photo, the Einsteinhaus (Einstein house, in Bern, Switzerland) is shown in which Einstein rented the second-floor apartment after he got married in 1903. His wife, Mileva Marić, is shown at the lower part of the photo. They lived there from 1903 to 1905. While living in that apartment, Einstein produced the special theory of relativity, the photoelectric effect for which he received the Nobel Prize as well as the above equation, all in 1905!

Einstein alongside his mass-energy equivalence

This was not the only letter that excited the collectors’ imagination of Einstein’s souvenirs world-wide. Eight years later in his life, in 1954 (just one year before his death), he wrote a letter to the German philosopher, Eric Gutkind, that drew even more interest. That letter, though, had material content of interest that expressed Einstein’s religious views. That letter had been sold in an auction at Christie’s in New York in 2018 for the staggering sum of $2.9 million (£2.3 million).

Religious people of all religious persuasions had been claiming that Einstein was a religious man, because of his quotation, “God does not play dice”. The interpretation from this quote, the religious people claimed, was that he believed in God’s absolutism and determinism in designing the universe. But the reality could not be furthest from this truth.

Albert Einstein made that remark as a riposte to the quantum physicists upholding the “Copenhagen Interpretation” that a fundamental particle’s existence is probabilistic in nature. Einstein held the view that a particle would exist or not-exist with absolute certainty, it cannot be probabilistic. His views were very well articulated in his one and half page letter written in German to the German philosopher, Eric Gutkind, “The word God is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honourable but still primitive legends, which are nevertheless pretty childish”. He also said, “No interpretation, no matter how subtle, can change this”. Thus, his views on religion could not be more forthright than this and this letter had put an end to all those egregious interpretation of religious people.

Hounded by Hitler’s anti-Semitic ideology, Einstein had to leave Germany and eventually settle in America to work at the Institute of Advanced Studies, Princeton University in New Jersey. When he arrived at the Institute, he was asked, what equipment would he require to work properly. “A desk or table, a chair, paper and pencils”, he replied, “Oh, yes, and a large waste basket, so I can throw away all my mistakes”. He was working on the Grand Unified Theory (GUT) of physics, which would merge the four forces of nature into one unified force. He worked on this GUT for well over 25 years without being able to crack it and possibly made lots of “mistakes”. Those “mistakes” were not collected by the Institute, when it was under overwhelming pressure from the WWII events. But if it did, who knows those “mistakes” could give a technical direction to the problem he was tackling and bear handsome fortunes to the Institute in auction sales now.

The bits and pieces of great men (and women) of science and literature might be deemed “mistakes” and worthless now, but in the fullness of time those pieces might turn out to be invaluable gems. For example, when Einstein produced the general theory of relativity, he introduced a term called the “cosmological constant” in his equation to cater for the prevailing perception of static universe. Only a decade or so years later, when universe was found to be not static but expanding, Einstein admitted that the insertion of cosmological constant was the “biggest mistake” in his life. But now with the discovery of dark energy and dark matter, this cosmological constant is throwing a lifeline to the modern-day cosmologists. His admission of “biggest mistake” of cosmological constant itself seems to be a mistake.

Einstein’s contemporary man in the Eastern World, Rabindranath Tagore, the myriad-minded man and a Nobel Laureate in Literature in 1913, wrote a short but simple verse with a profound philosophical significance, which reads in Bengali:

Tagore’s verse:

যেখানে দেখিবে ছাই

উড়াইয়া দেখ ভাই

পাইলে পাইতে পার

অমূল্য রতন !

Translated into English, it could read like this:

                        Whenever you find ashes

                        Sift carefully my friend,

                        Might you even find

                        Gems invaluable.

Einstein was not only a man of great intellect, but also a great showman and a humorous individual. When he met Charlie Chaplin in January 1931, he said to Chaplin: “What I most admire about your art is your universality. You don’t say a word, yet the whole world understands you!”

“It’s true,” replied Chaplin. “But your fame is even greater; the whole world admires you, when nobody understands what you say.”

Dr A Rahman is an author and a columnist

Cultural, International, Life as it is, Literary, Political, Religious, Technical

The Illusion of Reality

The reality is considered to be the state of a thing or situation, not a notional idea or perception, that is unambiguous or obvious at a specific space and time. The state of reality is vivid, transparent and beyond dispute. A ‘real’ thing is there, right in front of the eyes of the viewer to observe with full consciousness. But, is reality as ‘real’ as it is claimed to be? Is there no illusion in viewing or observing something that is ‘real’?

Nearly a century ago (1930 to be precise), Tagore, ‘the poet with the head of a scientist’, and Einstein, ‘the scientist with the head of a poet’, debated (and some would say, clashed) on the nature of reality at Einstein’s home outside Berlin. Einstein held the notion of reality that was vivid, transparent, visible, sort of ‘moon was there, whether one looked at it or not’, ‘a beauty was there, whether one observed it or not’. Reality arises from physical presence that cannot be denied or disputed.

On the other hand, Tagore held the view that reality of all physical objects, truth, beauty and so forth was dependent on human consciousness. Without human consciousness, the reality of anything was incoherent and irrelevant. He maintained that this world was a human world – the scientific view of it was also that of a scientific man. Therefore, the world apart from us does not exist, it is a subjective world, depending for its reality upon our consciousness.

Reality is not always ‘real’ as we view it; it can deceive our perception, our senses and consciousness or sense of reality may be partial or incomplete. Let us look at the Figure given below. The light from a distant star can be bent by the gravitational field of the Sun before it reaches us and then we view the position of the star at its ‘apparent position’. Of course, with scientific investigation, taking other parameters into consideration, the ‘real’ position of the star can be accurately determined. But to a common man, the ‘apparent position’ is the ‘real’ position of the star, he can point it out in the sky with his own fingers and that is the reality for him!

The moon is the nearest celestial body from earth. Even then, what we see or do not see of the moon may not be the real thing. For example, we may not see the moon due to cloud cover, but that does not mean the moon is not there in the sky. In Islam, religious events are fixed by the sight of the moon and the lack of sight of moon does not mean that the moon is not there in reality. That illusion of absence is taken as a substitute for reality. The light we get from our nearest star, beyond sun, comes to us four years after it had been emitted. In other words, our reality is four years behind the present time. We can get light or radiation from a star or a galaxy some 100 million or 200 million or 1000 million light years from us and during that time that star or galaxy may have died or disappeared. So, our reality of the existence of that star could be totally out of place.

The nearer an object is from us, the more accurate is our perception of the reality of that object. However, on the miniscule scale of atomic and sub-atomic realm, i.e. quantum field, our reality takes another knock. In there, particles like electrons, quarks etc take on dual role of particles and waves – which one at which point no one knows. An electron whizzes around the nucleus of an atom as waves, but when an energy is given to it or taken away from it, it behaves like a particle. Only the act of observation can determine the true nature or the reality of the electron. In quantum mechanics, it is axiomatic that only in the act of measurement does an electron become real. An unobserved electron is unreal (Copenhagen interpretation).  

However, an observed electron does not behave exactly the same way in various circumstances. A concrete example is the double slit experiment when electrons are fired one at a time and interference pattern is observed on the screen due to wave nature of electrons. Now, if a detector is placed to detect which slit the electron is going through, the interference pattern disappears. If the detector is then switched off, leaving all other arrangements intact, the interference pattern reappears. It is, as if, the electron does not like to be detected which way it is going. In other words, the act of observation modifies the outcome. Thus, the act of observation in this instance does not give the reality; rather the very act of observation changes the outcome of the reality.

The view of reality in the cosmological scale may be somewhat misplaced, as objects may not be exactly where they apparently appear to be. Also, in the ultra-small sub-atomic fields, objects cannot be assigned any particular positions based on physical principles. Only an act of observation may offer the object a specific position and that may be construed as the reality. But strangely that act of observation may change the otherwise reality!

Over the centuries and millennia, people had been narrating different ‘real’ stories. Moses, the prophet of Judaism, saw a bush-fire in the corn field right in front of his eyes and when he went nearer, that bush-fire disappeared, he saw nothing was burnt and received the God’s command not to approach it any further. To him, the event was vivid and real (although we now know that he witnessed a mirage). To George W Bush, the command from God to invade Iraq was real (unless he made it up). To millions of fanatic religious people, the existence of God or Allah or Yahweh is absolute and real; heaven and hell are real! It is the state of their mind that dictates reality.

Thus, there does not seem to be a universal notion or narrative of a reality that is true to everyone at every occasion. Reality seems to be subjective, depending on individual’s state of mind or consciousness, as Tagore had asserted. What is real, vivid and utterly true to someone may be totally unrealistic, utterly non-sensical to another person with a different state. Reality can thus be an illusory notion.      

Dr A Rahman is an author and a columnist.

Advanced science, Astrophysics, Cultural, International, Technical

Mysterious dark matter and dark energy

Physics is traditionally viewed as a hard subject requiring a great deal of mathematical prowess, devotion and perseverance to muster the subject matter. To a large extent, it is definitely true. But it does also offer, in its turn, a great deal of satisfaction, excitement and sense of achievement.

The 21st century physics, spanning from quantum computing to super-thin layer material called graphene to ultra-efficient LED bulbs to efficient harnessing of renewable energies to black holes to dark matter and dark energy, the range of topics is endless and it will disappoint no one with its vast challenges and ensuing excitement.

In our day-to-day lives, we encounter matter comprising protons and neutrons bundled together at the centre, called nucleus, of an atom and electrons whizzing around the nucleus. Some decades ago, these protons, neutrons and electrons were thought to be the fundamental particles of all matter; but not anymore. Now, quarks (six types) are thought to be the fundamental matter particles, which are glued together by force particles to form protons and neutrons.

These atoms and molecules making up matter here on earth are what we are accustomed to. The laws of physics, or for that matter of natural sciences, were developed to explain the natural processes as we encounter in our lives.

The basic physical principles are like these: a body has a definite size comprising length, breadth and height; it has a mass and weight; it is visible when there is sufficient light. If we push a body, we impart momentum, which is the product of mass and velocity. As it has the mass, it has gravity, meaning it attracts every other body and every other body attracts this body. These are the basic properties of a body as described in classical physics.

But there is no reason to be dogmatic about these basic principles. These principles can change here on earth or in our galaxy or somewhere outside our galaxy. When they do change, we would feel that things have gone topsy-turvy.

We live on a very tiny planet, called Earth, which revolves round the star, called Sun. There are eight other planets, thousands of satellites, comets and asteroids, all held together by the gravity of the Sun. The Sun, though extremely bright and overwhelmingly powerful to us, is a small star in our galaxy, called the Milky Way. It is estimated that there are over a billion, yes, 1,000,000,000 stars, many of them are much bigger than the Sun, in our galaxy. Now our galaxy is by no means the biggest or dominant galaxy in the universe. Cosmologists estimate that there are around one billion galaxies in our universe! Some of these galaxies are hundreds or even thousands of times bigger or massive than our galaxy. There are massive black holes at the centres of most of the galaxies, exerting gravitational pull to keep the galaxy together. Some of these black holes are millions of times bigger than the Sun. Now we can have a feel of how big our universe is!

Physics, or more appropriately astrophysics, studies the processes of these vast expanse of celestial bodies. The Sun as well as our galaxy, the Milky Way having over a billion stars are not static. The stars are spinning, the galaxy is spiralling, and everything is in motion.

Strange glow from the centre of the Milky Way

It was estimated, purely on physical principles, that the stars at the edges of a galaxy should move slower than the central ones, as the force of gravity of the galaxy is weaker away from the centre. But astronomical observations show that stars orbit at more or less at the same speed regardless of their distance from the centre. That was a great surprise, indeed shock, to the astrophysicists. The way this puzzle was eventually tackled was by assuming that there are massive unseen matters that exert tremendous amount of gravitational pull to keep the outlying stars moving at nearly the same speed and that mysterious matter is called the dark matter.

There are other tell-tale signs that there is something amiss in the material accounting of the universe. A strange bright glow spread over the length of the Milky Way was thought to be due to ordinary pulsars (pulsating stars) along the length. But now it is thought that dark matter may be responsible for this glow! But how does it do that, physics does not know yet.

But is this dark matter a fudge to solve the apparent conflict of physical behaviour with observations? Not really, this is how science progresses. Well thought out ideas are advanced and those ideas are tested and cross-examined against observations and the idea or concept that passes the tests is taken as the valid scientific concept.

But how do we know dark matter is there, if we cannot see them. We cannot see them because dark matter does not interact with light or electromagnetic radiation such as visible light, infra-red, ultra violet, radio waves, gamma rays and so on. Light goes straight through the dark matter, as if it is not there.

It should, however, be pointed out that dark matter is not the same thing as black hole. A black hole is made up of everyday particles (matter particles and force particles) – electrons, protons, neutrons, atoms, molecules, photons etc. Its gravity has just become so strong (because of its mass and super-compacted size) that it pulls and crushes everything to its core and nothing can escape from its clutches, not even light! A beam of light coming close to a black hole is pulled right insight and that is the end of that light beam never to be seen again!

Dark energy expansion

Dark matter, although invisible, does exert gravitation pull and this gravitational pull that makes dark matter attractive to scientists. The Universe, although expanding, is not in danger of runaway expansion. There is something that is holding the whole thing together and that something may be the dark matter.

Immediately following the Big Bang, the then Universe expanded very rapidly, known as inflationary phase, for tens of millions of years followed by expansion for some billion years and then it stabilised for a few billion years and now it is again in the expansion phase. The present expansion is that the space itself is expanding and so every star and every galaxy is moving away from every other star or galaxy. What is giving these celestial bodies energy (repulsive in this case) to move away from each other? Scientists came up with the proposition that there must be some unknown, unseen energy, which is now called the dark energy.

On purely material and energy balance of the Universe, it is thought that our visible (and known) Universe accounts for only 4.9 percent of the total Universe, dark matter accounts for 26.8 percent and dark energy for 68.3 percent. So, we only know in the vast mind-boggling universe extending over 13.8 billion light years a meagre 5 percent and the remaining 95 percent is hidden or unknown to us!

Scientists all over the world are trying hard to find evidence of dark matter and dark energy. CERN’s Large Hadron Collider (LHC) is trying to find any remotest evidence of dark matter and energy. On theoretical basis, some scientists are proposing that dark energy may emanate from a fifth form of force, which is yet unknown. The four forces that we know are electromagnetic, weak nuclear, strong nuclear and gravitational forces. The fifth force may be a variant of gravitational force – a repulsive gravitational force – that comes into play in the vast intergalactic space.

When Einstein produced the general theory of relativity in 1915, he introduced, almost arbitrarily, a parameter, called the cosmological constant, into the theory to counter the effects of gravitational pull and make the Universe a static one. That cosmological constant effectively introduced the repulsive effects. It may be pointed out that the Universe was thought to be static at that time. But only a few years later when it was incontrovertibly shown that the Universe was, in fact, expanding, Einstein humbly admitted that it was his “biggest mistake”. Now, more than hundred years later, it is assumed that the cosmological constant may be considered to be the quantity to cater for the dark energy! Could Einstein’s “biggest mistake” be a blessing in disguise, it offers not only a correct presumption but also a saviour of modern cosmology?

  • Dr A Rahman is an author and a columnist