Developed in the 1920s by Schrödinger, Pauli, Heisenberg, Bohr, Born, Fermi, Dirac and others, quantum mechanics describes the laws of nature for the subatomic world.

These laws are unfamiliar to our everyday experiences and seem to be strange and revolutionary when compared to the laws of the classical physics and the laws governing the macroscopic universe.

**Puzzles of Quantum Mechanics**

Two of the mysteries of Quantum Mechanics are:

- Wave-Particle Duality: Subatomic particles such as electrons behave as both particles and waves.
- Observer and the act of measurement (Schrödinger’s cat paradox): The act of measurement or observation by an observer influences the outcome of an experiment. The paradox goes like this: before the observation the cat inside a box is dead and alive simultaneously. Once the observation is made, the cat stays either dead or alive. This implies that consciousness decides the outcome of the experiment.

**Quantum Entanglement and Teleportation**

Experiments have shown that influencing one particle such as a photon in a system of particles instantaneously affects other particles in the system no matter how far the particles are from each other. Quantum Entanglement also suggests that a quantum state such as a particle can be transported from one place to another. This is known as quantum teleportation.