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Black Hole Information Paradox

  The universe is not stagnant, it expands every minute,  every second  at an accelerating pace. It came into being through a colossal explosion - The Big Bang . It gives birth to subatomic particles, stars, dust, gas clouds, etc. These bodies then carry on with their cycles. When massive stars run out of energy, they collapse into dense bodies like neutron stars or black holes through a supernova explosion.  Source -  nasa.gov   A black hole is a region in spacetime where gravity is so strong that even light cannot escape it! Black holes consist of an event horizon,  the surface layer of the black hole , and a singularity,  the region where the spacetime curvature becomes infinite.  The theory  o f general relativity suggests that mass is stretched when thrown into a black hole.   In 1974, English Physicist Stephen Hawking discovered Hawking Radiation. What is Hawking Radiation, to be exact?  Hawking Radiation states that black holes are slowly losing their mass. The hot, dense bodi
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Quantum Entanglement and Schrodinger's Cat

In 1935, Austrian physicist Erwin Schrodinger came up with a thought, what was it? He assumed a cat with a bomb inside a box. There are 50% chances that the bomb would explode but there was no way to find it out until the box is opened or we observe it. So there is a 50 percent chance that the cat is alive and a 50% chance that the cat is dead. In quantum mechanics, the cat is both dead and alive at the same time; we called this superposition.

Source: Huawei 




Now let’s perform the same experiment with 2 cats, i.e.,
Cat A and Cat B. The possibilities will be the following –





But according to quantum mechanics, we can eliminate the first two of them and the outcome is that either cat is alive or dead or visa-versa.


Source: interestingengineering.com


But until we observe them they are in superposition. As soon as we observe them, we can know the state of both the cats. For instance, while observing if cat A is alive then, cat B will be dead and vice versa. In such a case, quantum physics says that these two cats are entangled. This implies even if these two cats are at two opposite ends of the universe.


Source: ysjournal.com

Now let’s talk about this in the case of sub-atomic particles like electrons. Electrons inherit a property called spin, we have two states spin up and spin down. Let’s understand what is spin. Electrons have three inherited characters which are spin, charge, and mass.

The spin up and spin down direction are corresponding to the spinning in
the +z or –z-direction

Until we measure the spin of the electrons they are in a superposition, i.e., both spin up and spin down simultaneously.

Source: chem.libretexts.org

You might be thinking this is some theoretical stuff and have no practical uses for it, but that’s not true, Quantum entanglement is used in - quantum cryptography, quantum teleportation, quantum computing, etc. 

Source: physicsworld.com


Fun fact: Schrodinger developed this experiment to prove that wave-particle duality was not true and fortunately he gave us a theory that is the base of the internet. This story is for another day.

This blog was written by - Hriday Agarwal

 


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