Quantum Entanglement:
Spooky action at a distance as called by Einstein.
In a Vague way, it says communication can occur faster than the speed of light hence the word ‘spooky’, as special relativity told us that nothing can travel faster than C(speed of light =3x108m/sec).
It is works on principle that result of a system depends on method or way of measurement. This is Quantum mechanical law and is not applicable to Classical mechanics (Newtonian mechanics- daily life phenomena).
If this does not confuse you, go back and read it again. Confused? Yes! How can an experiment’s result depend on way of observation??
In a Vague way, it says communication can occur faster than the speed of light hence the word ‘spooky’, as special relativity told us that nothing can travel faster than C(speed of light =3x108m/sec).
It is works on principle that result of a system depends on method or way of measurement. This is Quantum mechanical law and is not applicable to Classical mechanics (Newtonian mechanics- daily life phenomena).
If this does not confuse you, go back and read it again. Confused? Yes! How can an experiment’s result depend on way of observation??
Let’s bring in our
favorite Schrodinger's cat, in this experiment, cat is in superposition state of
being both dead and alive unless we open the lid and make a measurement, then
on it will be either dead or alive.
Quantum Entanglement can be explained by this experiment. We need 2 cats in 2
different boxes such that the quantum states (here being dead or alive) are
entangled, that is if one is alive other will be dead.
Let us use 2 methods, be it method 1 and method 2.
- Our method of measurement affects the result or changing the property being measured alters the result.
- Measurements affect each other.
METHOD 1
|
METHOD 2
|
0(Dead)
|
N(Dead)
|
1(Alive)
|
Y(Alive)
|
States of cat in box 1:
On measuring the state of cat 1 using method 1, we obtained result 1 implies cat in box 1 is alive. Similarly method 2 gave us Y that is cat is alive in box 1. Now, if we come back and measure again via method 1, the probability of this result is 50% again, which means it can be either 1 or 0 though we got 1 before there is no assurance that we get 1 again, we could get 0 for same exact method of measurement, it can be seen that measurements influence each other.
States of cat in box 2:
When method 1 gave result 1 for cat in box 1, cat in box 2 gives result 0 for same measurement and when method 2’s result of cat in box 1 is Y, it gives us N for cat in box 2. Each time the result of Cat in box 2 changes instantly and is in accordance with result of cat in box 1, happens vice verse too.
When method 1 gave result 1 for cat in box 1, cat in box 2 gives result 0 for same measurement and when method 2’s result of cat in box 1 is Y, it gives us N for cat in box 2. Each time the result of Cat in box 2 changes instantly and is in accordance with result of cat in box 1, happens vice verse too.
Each cat may produce random results but when compared with each
other they are always impeccably associated.
It is as if they communicated, but these results will be accurate even when the boxes are placed cities apart.
It is as if they communicated, but these results will be accurate even when the boxes are placed cities apart.
- Usually cats are replaced by particles such as photons, electrons and their quantum states being spin of the particle.
- Measuring one will tell the Quantum state of other with complete certainty.
- Quantum states of particles are indeterminate unless measured.
- Quantum Entanglement is widely used in powerful computers, Quantum computation and Quantum communications; they can provide secure codes via quantum encryption.
