Parallel Universes

Around 13.7 billion years ago everything we know of in the cosmos was an infinitesimal singularity. Then, according to Big Bang Theory some unknown trigger ( which a few scientists believe may have been dark energy ) caused the universe to expand and the universe has been expanding ever since (though the rate of expansion is slower now as compared to that at the time of the Big Bang).

When we consider the space-time continuum to be a plane, then the idea of parallel universes comes into play. A high energy particle was recently spotted over Antarctica and according to the scientists the particle blasted up through the ice of Antarctica setting off the Antarctic Impulsive Transient Antenna (ANITA), several other particles like this were also detected. These particles looked like ultra high energy neutrinos; however, ultra high energy neutrinos should not be able to pass through the Earth. In order to explain this there was a theory that these particles belonged to a parallel universe where things were the opposite of our universe: time moves backwards, left is right, and up is down.

Now we will understand the idea of parallel universes; however, we must first familiarize ourselves with superposition and quantum entanglement. I will only give a brief introduction of these topics as I have individually taken them up in my other posts.

We all have heard about the famous Schrödinger Equation, which tells us about the wavefunction of a particular particle or system.

In order to understand this please read my article on superposition.

Consider the entire apparatus explained in the other article as a quantum system. Now the probability that the cat will die or will not die (as a result of decay taking place or not taking place) will be in superposition.

Following is the quantum state of the system :

\[ \frac{1}{\sqrt{2}} (|0> + |1>) \]

It signifies that there exists a uniform superposition of the |0> and |1> state.

As soon as we open the box, the cat is forced to choose it’s state and hence, we find that there is only one outcome and both the outcomes have an equal probability.

Please read my article on entanglement to get a deeper understanding of the next topic. Here I will only summarize the phenomenon.

Quantum Entanglement, in general, is when two particles or systems get connected i.e. these particles continue to interact with each other regardless of their separation. They interact through the transfer of Quantum Information. In entanglement the quantum systems of the particles get linked and they have the same wavefunction. Now in the experiment the cat, the radioactive substance, the detector, the poison, and even the observer get entangled. In this case the experiment also gets entangled with the environment. And whenever a particle gets entangled with the environment it undergoes decoherence due to which our universe branches into what we call a Parallel Universe.

I have posted a separate article about DECOHERENCE, click on the following link to read it : Decoherence in quantum systems

Hence, we see that the quantum state, that I mentioned earlier, is being conserved as in one parallel universe the state is |0> and in the other it is |1> and thus, we also have superposition.