The Beginning
The
superposition principle in quantum theory states that if a system is observed
to be in one of several states, then it could exist in a combination of states
at one given time. The Schrodinger cat experiment illustrates this principle.
In
this experiment ,the cat is placed in a sealed box along with a radioactive
substance, some poison and a Geiger counter.
Once the radioactive substance has decayed, the counter detects it and
unleashes the poison in the box which eventually kills the cat. But the beauty
of this thought experiment lies in the radioactive substance. Since the decay
is a random process, it is not possible to predict the process and hence the
actual state of the cat. If we analyse this experiment, we realize that before
we observe the cat, the cat can be in two different states both dead and alive
at one given instant of time. It is only after the observation that we conclude
with one of the states.
This
is a great experiment that allows us to incorporate the quantum theory for
large objects such as the cat and the observer in this experiment lies outside
the system (box).If the observer lies inside the system under scrutiny, the
integrity of the experiment is automatically destroyed. From my understanding
about system and observer, my being inside the system will bring in extra
variables which in turn will affect the original experiment to start with.
Although
this experiment enables us to think about macroscopic objects in terms of
quantum states, if the system is the entire universe (Which we are a part of)
becomes a problem since we are inside the system.
Several
years of mind bending experiments from great minds and classical logic suggests
that observer must be outside the system under study to keep it consistent and
not ruin the integrity of the original system. Since we do not know what is
outside the observable universe (for now) i.e. beyond 13.5 billion years of the
universe or in other words- The Big Bang, logic dictates that we need a model
that allows for the observer to be outside the system and yet inside.
The
model from my amateur understanding on the subject should look something like
in the figure below.
This model suggests that quantum fluctuations in a black hole could
result in a separate cone that is outside the realms of the present universe
(maybe another dimension) and yet originating from the same universe. This way
we, as observers ,are outside. The objective of this model is to understand the
mechanism of the universe before the big bang in terms of quantum states by
observing black holes. Although studying the black hole for such clues is a
task that is unimaginably difficult. Perhaps the universe that we live in
resulted from one such quantum fluctuation inside a black hole. We would never
know.
I
would also like to emphasize that the above fig does not denote a geometrical
model of the universe but built on conjecture.References - Three Roads to quantum gravity- Lee Smolin
Krish Ramkumar
For me 'Schrodinger's Cat' Thought experiment has more philosophical implications especially with respect to Freewill and Choice. The moment you open the box and look inside the real picture is there before you and the question of choice and speculation vanish. The experiment basically highlights the uncertainty that exists at the quantum level. let me quote what I have written in my book -" it is choice that is deterministic here. The fact that we make a choice is because there is a freedom to do so. Where does this freedom come from? You have the freedom to choose and what you choose becomes your reality. On the question of reality, isn’t it a subjective view? We have seen the uncertainty that exists at the quantum level. There is nothing deterministic about the basic building blocks of matter itself. At the quantum level we talk in terms of probabilities and that matter itself is interweaving of probabilities. Then isn’t what you see a probability and therefore an illusion?" Being inside the system only compromises the integrity of the experiment. An experiment remains as such only till the results are known, after that the result is the reality. For me The big Bang is The Beginning and I am on this side now and may be speculate what it is like before that on the other side. I appreciate your line of thought and as a scientist. But since I have not been in touch with the latest thought process in theoretical Physics I tend to restrict my understanding to philosophical interpretations to the purpose of life and the creation of this universe. I believe that there are no frontiers to science, the more you discover the more there will be left to understand.
ReplyDeleteThanks for the insightful response mani athimber.
ReplyDeleteIf we try and bring in quantum uncertainty to free will. From my opinion, the choice that we supposedly make itself might just be one of the probable several outcomes. The brain by itself is made up of elementary particles and might enable us to make only a probabilistic choice due to the intrinsic property of the particles. seems like science can only go so far and there is always some thing that is unanswered. Philosophy helps in filling the void that science is unable to fill. :)
I asked a close friend and ex colleague of mine Induchoodan Menon who left the bank to pursue his passion for Physics mainly in the realm of quantum mechanics and thermodynamics and has come out with his own findings and presented his papers on the same, to give his comments on what you have written. I am giving below his views for your interest.
ReplyDeleteDear Subbu,
I went through the well written blog. I had similar views before I started my work in quantum mechanics and relativity. I think now by and large the paradox of Schrodinger's cat has been resolved. The basic premise on which the paradox stands is that time has the same property in the microscopic and macroscopic realms. This is because we take the concept of time for granted. In fact, time has a few more tricks on its sleeve. For example, in the microscopic realm time has the property of reversibility. This means that a microscopic event when video-graphed and played backward would follow all physical laws. This is not the case in the macroscopic events. Here time loses its directional symmetry and acquires the progressive nature. If we replay a video-graphed macroscopic event backward, it would look nonsensical. Imagine the macroscopic event like the breaking of a glass tumbler while getting knocked down by accident. We will see all broken pieces of glass coming together to form a beautiful glass tumbler. Can such a thing happen in nature ?
The cat in the Schrodinger's story is a macroscopic entity. It does not exist in a world of superposition. The superposition of the various states can happen only in the microscopic world with reversible time. Some thing strange happens to time when we move from the microscopic to the macroscopic. I have done lot of work on this and have found that if we introduce a hypothesis that all particles absorb an infinitesimal quantum of energy in its interactions with vacuum, then it could explain the progressive nature of time in the macroscopic world while retaining its reversibility in the microscopic realm. I found that in the process we could kill three birds could in one shot. This absorption of the infinitesimal quantum of energy by particles while explaining the progressive nature of time, also would account for the gravitation and the expansion of the universe. Mind you, the expansion of the universe has thrown up new problems in recent observations as they have found that the rate of expansion of the universe is increasing and not decreasing as proposed by the big bang theory. This new picture with particles absorbing energy from vacuum would explain the accelerated expansion beautifully. In fact, if the hypothesis of the particles absorbing energy from vacuum is correct, then it would seem that the Universe came into existence not in a big bang, but rather the energy condensed into matter in a slow and steady process just like like the way dew is formed in the early morning sky.
The interesting thing is that time would have been progressing at much slower rate than what it does now in the present epoch. But if we do not account for this change in the intrinsic property of time, then it may seem that a big bang explosion commenced the expansion except that it cannot explain the accelerated nature of the expansion. Note that there is no justification to assume that time as we know now had the same property in an earlier epoch. But then that is how science progresses. Initially we take the simplest case and then build complexity into it till it explains all phenomena.