Principle of Complementarity

Narendra Bhandari

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Principle of Complementarity

The principle of complementarity implies that opposites are complementary and, together they describe the real world. Neils Bohr who propounded the basics of quantum mechanics had great difficulty explaining it, and he did it through his principle of Complementarity., considered to be the most revolutionary and significant concepts of modern physics. The Western philosophers and scientists had a lot of difficulty in understanding and developing quantum mechanics. Some experiments gave contradictory results , implying that sometimes light or a photon (or electron) behaves like a compact object i.e. a particle and some times like a wave such as a ripple we see in a pond. In the famous two slit experiment, a beam of photon shines through two slits and hits upon a photographic plate behind the slits. The experiment can be run in two ways: one with photon detectors right beside each slit so that the photons can be observed as they pass through the slits and or with detectors removed so that the photons can travel unobserved. When the detectors are in use, every photon is observed to pass through one slit or the other and essentially the photons behave like particles. However, when the photon detectors are removed, a pattern of alternating light and dark spots, produced by interference of light are observed indicating that the photons behave like waves, with individual photon spreading out and surging against both the slits at once (Fig. 2). The outcome of the experiment then depends on what the scientists want to measure. But how do photons “know” or realize that they are being observed by the detectors remains a mystery. In the living world, change of behavior when being watched is a well known psychic phenomena but change of behavior in the material world is baffling. Does it mean the particles have a psyche? Scientists don’t agree with this interpretation but have explained it on the basis of plurality of attributes.

This dual behavior of a photon could not be reconciled because of the basic nature of waves and particles were considered to be exclusive or different from each other. Bohr explained this by saying that contradictory behavior is complementary and used the Chinese concept of Yin and Yang (Fig. 3), which are both opposite but exist together and are required for sake of completeness. This is easily understood in the framework of Anekantvad which accepts that opposites and extremes allow us to learn the true nature of reality. As propounded in Jainism, reality can manifest different perspectives at different times. It may be noted that, in contrast, Buddhism avoided extremes and Buddha favored the path of the Golden mean to reconcile contradictory views.This is a fundamental difference between Jainism and Buddhist approach.

Thus complementarity became the cornerstone of quantum behavior, to which we will revert in some detail later on.

Principle of Symmetry:

Nature loves symmetry. Symmetry has been the backbone of understanding nature. The life forms, galaxies, planets, trees, molecules, atoms etc are all symmetrical. There are many forms of symmetry. Left and right symmetry, mirror symmetry, time symmetry and so on. Pictorially, symmetry has been very elegantly depicted in a sculpture found in the Jain temple at Ranakpur (Fig. 4). The conservation laws, on which both classical and quantum physics are based are an outcome of the symmetry principle. This has also been very effectively used to understand behavior of elementary particles by Gell-mann and others. Elements (Mendeleeve’s Table) are arranged in eight fold symmetry. These 118 elements can be arranged in the form of octets, their properties repeat after every eighth member. and so are the elementary particles. In fact, symmetry principle has been used as very powerful tool to predict the existence of many unknown particles by Gellmann, another Nobel Laureate and a profound thinker. He arranged the elementary particles in “eightfold way” and was eventually able to predict and discover quarks, the
smallest constituents of matter known to day. It is known now that elementary particles (called hadrons) can be organized in octets (8) and decuplets (10) whereas leptons in nonets (9).The universe itself is known to be formed by super symmetry.

Some times a symmetry is also violated like parity is a mirror symmetry which is found to be violated in certain reactions. Thus existence of symmetry and its violation, both are of fundamental importance in understanding the nature of the basic processes governing the behavior of fundamental particles.

Uncertainty principle: Applicable mainly to the microworld, the Heisenbergs Uncertainty principle states that it is impossible to completely quantify all the parameters describing the state of a particle precisely. If measurement of some physical quantity is made, then according to quantum physics, the state of the particle is deemed to have changed instantly into a different state. It is not because one can not measure the parameters accurately because of limitations of the instruments or their precision but that the measurement can not be made without changing the state of the particle. For example, both the parameters in the pairs of energy (E) and time (t), or position (x) and momentum (p) can only be known within some uncertainty Δ

(ΔEΔt=h; ΔpΔx=h), defined by the Planck’s constant h, which has a very small, but none the less, finite value. Uncertainty principle is one of the most fundamental principles applicable to the realm of all the physical microworld

This indeterminacy may also be the root cause of Syadvada (ºªÉÉnÂù ´ÉÉnù), another Jain concept. Syādvād, a corollary of Anekantvad, is also considered as a cornerstone of Jain philosophy. It has been translated as “perhaps”, or “May be” which appears to me as very qualitative (or crude) definition.

In a larger perspective, the uncertainty principle offers a choice, though limited, in behavior of nature. In the domain of biology, such uncertainty can allow evolutionary changes. The uncertainty in energy levels, e.g., provide a scope for a variance in chemical reactions, leading to different products and thus bring about evolutionary changes.

The Jain philosophy recognizes only three entities in the universe, the Gyata (knower), Gyeya (the object to be known) and the Gyan (knowledge) (Fig. 5).

The transfer of knowledge from the object to the knower changes both the object and the knower. This is precisely what happens according to the uncertainty principle so that with every measurement, the object changes and it is not possible to determine its state completely, which may require several measurements.

Exclusion Principle: The Principle, first enunciated by Pauli states that two elementary particles in the same” state” can not exist together. No body can state it better or more rigorously or elegantly than Kabir, when he, after he gained enlightenment said” When I am there, God is not there and when God is there I don’t exist, because the space is too narrow to accommodate both of us (being in the same state).

Having pointed out that the laws which operate upon the gross universe and the microuniverse are different, we revert to the two propositions made at the beginning of this article to define Anekantvad.

The first proposition is easy to prove even by simple logic. If the universe is without a beginning, then when did the vast diversity, we see today in the multifaceted universe, begin, if everything originated from “one”. If diversification started from the very beginning then, it could not be “one” but already “many” to start with. If diversification began at some later time, then the “one” survived without diversifying for some finite time. What then caused it to diversify at that particular point of time? According to causality, it can not by itself , without a cause, multiply so there has to be a causative agent to bring about the diversification. This argument thus negates “one” being responsible for the diversity of the universe.

Even “one” can not exist by itself. That has given rise to the well known Mach’s principle in physics. We may recall here that Mach’s principle deals with the concept of origin of inertial mass. Broadly speaking Mach’s principle states that the inertial mass of a body is solely due to interaction of other bodies in the universe. Heller (1975) mentions it in the following way : ” The local inertial frames are entirely determined by the distribution and motion of all matter present in the universe” and Einstein formulated it as ” the entire inertia of a point mass is the effect of the presence of all other masses, deriving from a kind of interaction from the latter” There is yet no “proof” for this principle but Einstein is said to have derived much inspiration from the Mach’s principle for development of his Theory of Relativity.

The implication is that inertial mass cannot exist in isolation. Now we may ask if this principle can be extended to other physical entities or even spiritual entities? Are we living in a totally interactive world and everything here is interactive. The same may be postulated for life (jiva) or consciousness. Life certainly cannot exist in isolation. If all living species, except one, in the universe or even on Earth vanish, the last one also will not be able to survive. Therefore the life is a result of interdependence (or interaction) with other living species. The principle of non-violence immediately follows since the whole becomes a cause for the existence of a part of it and both are indistinguishable. In effect, when, one does any harm or kills some body, howsoever primitive, one is killing a part of one self, because his very existence is interactive in nature. It is like committing a small suicide.. Thus the inertial mass, which is a physical entity and the consciousness, which is a spiritual attribute, are both interactive in nature and their origin is a consequence of interaction. We will return to this argument at the end when we discuss entanglement.

To discuss the second proposition, we now discuss the laws applicable to the microworld within the framework of the quantum mechanics.