Future Physics – Will It Be Advaita-like? – Part 3
The theories of Physics can be conceptually understood on the basis of either “particles” or “fields” for the structure of matter. The mathematical formulae derived based on both models (either as particles or as fields) have proved useful in designing machinery, in conducting the day to day operations requiring the application of the principles of physics and also in the prediction of the outcome of a process of measurement or experiment. However, we run into difficulties when we try to merge both concepts, for example, as in the development of a theory applicable at the edge conditions like the origin of the universe or near black holes. This is the main reason why physicists are unable to come up with a Unified Field theory that can subsume all the four natural forces – electromagnetic, weak nuclear, strong nuclear and gravitational forces – into one single equation. We shall now examine how our conceptual frame-work of either a particle or a field for the structure of matter proves inadequate to represent the reality observed in nature.
Whenever we conceive of a particle, we think that the particle physically exists at some location. For example, we are pretty sure that all the tiny little particles that constitute our blood, muscle or bones certainly exist 24/7 within our bodies. But Physics shows that “a particle inside your body is not strictly inside your body. An observer attempting to measure its position has a small but nonzero probability of detecting it in the most remote places of the universe. Relativistic quantum particles are extremely slippery; they do not reside in any specific region of the universe at all.” Thus a part of you may be in London or New York, but at the same time and simultaneously, that part can be found on the moon or even on the Andromeda Galaxy!
Secondly, the localized nature of the particle is not dependent on the particle but on the viewer who looks at it! For example, say, you find a particle localized in your kitchen. But “Your friend, looking at your house from a passing car, might see the particle spread out over the entire universe. Not only does the location of the particle depend on your point of view, so does the fact that the particle has a location. In this case, it does not make sense to assume localized particles as the basic entities.”
Further, you may feel it is easy for you to count the various particles, say, you find in your house. “You go around the house and find three particles in the dining room, five under the bed, eight in a kitchen cabinet, and so on. Now add them up. To your dismay, the sum will not be the total number of particles.”
We get a still more bewildering a picture when we consider a vacuum. Normally for us, vacuum is a place where no particles are present. But both the theoretical studies and actual physical experiments conducted demonstrate that the vacuum is anything but a calm serene empty place of nothingness. It literally boils with constantly appearing and disappearing particles that a tremendous amount of energy gets engendered in the process. The ever expanding nature of the universe is, in fact, thought to be due to the vacuum energy in space.
This vacuum energy is experienced in a strange way by a traveler in space. If the spaceship he or she is in is at rest or uniform motion, he would feel that he is in a vacuum space. But the moment the space ship speeds up, he will feel he is passing through a hot bath of particles!
We also imagine that each individual particle retains its separate identity and will always be recognizable as an independent entity. But under certain conditions of temperature and pressure, the particles get so much entangled with one another that it is not any more possible to distinctly identify each particle. The whole mass behaves as one single un-parted entity. This is known as Bose-Einstein condensate.
Summing up, we may say that though we conceive particles to be like tiny billiard balls, modern physics demonstrates that “particles” are nowhere like that at all. We find that they “cannot be localized in any finite region of space, no matter how large or fuzzy it is. Moreover, the number of the putative particles depends on the state of motion of the observer. All these results taken together sound the death knell for the idea that nature is composed of anything akin to ball-like particles.”
Now let us examine how far the concept of “fields” holds good.
When we think of a ‘field’, what normally comes to our mind is something like a weather map showing the variations in temperature in different locations or a topographic map that shows the contours of heights of places above mean seal level. When such classical maps are prepared, it is assumed that the variable (temperature or height in the example given here) varies continuously across the region and points of equal value can be joined by a line called the contour line. In the application of quantum theory to fields, the concept of continuous variation will not be valid. Moreover, the value of a given variable at any place will be probabilistic and cannot be said to have a definite quantity. What exactly does a “quantum field” then mean? Even physicists cannot visualize the meaning, though one can calculate the probabilities pretty accurately as per the formulae developed based on the quantum theory.
Thus, a quantum field, unlike the classical field, “assigns abstract mathematical entities, which represent the type of measurements you could conduct, rather than the result you would obtain. Some mathematical constructions in the theory do represent physical values, but these cannot be assigned to points in spacetime, only to smeared-out regions. A classical field lets you envision phenomena such as light as propagation of waves across space. The quantum field takes away this picture and leaves us at a loss to say how the world works.”
The above analysis of particles and fields, though very simplistic and technically not rigorous, can still lead us to the conclusion that we are not very clear what exactly a particle or field is. It also shows us that “the standard picture of elementary particles and mediating force fields is not a satisfactory ontology of the physical world.” Some people coin terms like “wavicle” combining the words “wave” and “particle” to highlight that “the particles and fields should be seen as complementary aspects of reality.” We may give any clever name, but the name only covers up our ignorance in understanding what exactly the structure of matter is rather than providing any clarity. So Physicists are looking for possible new approaches in the future. And we find here Physics and Metaphysics shaking hands together.
The New Approaches in Physics:
Dr. Meinard Kuhlmann, Professor of Philosophy at Bielefeld University in Germany observed in a recent article that “a growing number of people think that what really matters are not things but the relations in which those things stand. Such a view breaks with traditional atomistic or pointillist conceptions of the material world in a more radical way than even the severest modifications of particle and field ontologies could do.”
A moderate version of the structural realism, known as epistemic structural realism, according to Dr. Kuhlmann, runs as follows: “We may never know the real natures of things but only how they are related to one another. Take the example of mass. Do you ever see mass itself? No. You see only what it means for other entities or, concretely, how one massive body is related to another massive body through the local gravitational field. The structure of the world, reflecting how things are interrelated, is the most enduring part of physics theories. New theories may overturn our conception of the basic building blocks of the world, but they tend to preserve the structures. That is how scientists can make progress.”
He then raises the following questions: What is the reason that we can know only the relations among things and not the things themselves? The straightforward answer is that relations are all there is. This leap makes structural realism a more radical proposition, called ontic structural realism.
(To Continue)
