Saturday, May 7, 2022
NEWS- Magnetic Bubble could act as a saviour for Astronauts
Sunday, July 11, 2021
Delayed Choice Quantum Eraser Experiment
BY: Arjit Mishra
It is widely said that "efforts in the present decides our future" but what if I say actions in future affects past events! Yes you heard it right. As we aren't able to travel back in time ; it's hard to digest the fact.
But with the help of an experiment in Quantum physics it is possible!(At Quantum level). this experiment is entitled as Delayed Choice Quantum Eraser Experiment, It is basically an extension of Double Slit Experiment.
[NOTE: If you haven't read my double slit experiment blog, visit:https://theoarmi.blogspot.com/2020/05/double-slit-experiment.html otherwise you wouldn't get the concept behind the experiment]
We can conclude from double slit experiment that electrons show particle nature in the presence of an observer machine and show wave nature in the absence of same; Which indicates electrons somehow know whether they are being observed or not so that they can act accordingly.
That's Scary right! but there's a scientific explanation to the fact that doesn't completely but somehow justify this weird behaviour. Physicists say that there is a fuzzy space between creation and detection where any type of well defined particle doesn't exist at all. Copenhagen interpretation tell us that in this space a particle exist in the form of wave function[it is basically a distribution of all possible properties of a particle], this Probability is wave only which shows wave nature and form interference pattern but when an observer is placed the wave function collapse and the wave converts into particle which shows particle nature and form just two lines on the back wall.
In double slit experiment we placed an observer machine to detect which electron passes from which of the two slits but we failed in doing so thus Physicists executed Delayed Choice Quantum Eraser Experiment.
Before we go through delayed choice quantum eraser experiment we should first understand wheeler's Delayed Choice Experiment.
In Double Slit Experiment we kept the observer machine before the slits but in wheeler's Delayed Choice Experiment it is kept near the wall[on which patterns appear] and tried to observe the electrons exactly before when they collide so that they can't alter their behaviour accordingly. But the observations were shocking and weird, when electrons were observed they behave as particle and only for two lines ensuring particle nature and when they weren't observed they show wave nature and form interference pattern. Since the observer was observing the electrons just microsecs. before collision; this can be true only if electrons time back in time and decide their behaviour depending upon observance and non-observance. This experiment has again proved that Quantum Physics is weird.
Now, we shall see Delayed Choice Quantum Eraser Experiment:
In this experiment a Non-Linear optical crystal is placed behind the double slit which create entangled pair of electron passing through slit A and slit B moreover one particle of the entangled pair is allowed to move towards the backwall while other one is send towards the detector D3 and D4 in order to predict that electron has passed through which slit(either A or B).
[NOTE: If you don't know about entangled pairs, you should read my blog on Quantum entanglement and EPR Paradox, visit:https://theoarmi.blogspot.com/2020/08/quantum-entanglement-and-epr-paradox.html]
The Entangled Particles are entitled as "twin brothers". whatever happens with one, it also happens with other. If electron's second entangled partner is detected near D4 then electron must have passed through slit B but if second entangled partner is detected near D3 then electron must have passed through slit A. These Detectors are positioned in such a way that the second entangled particle should reach them after the collision of first one on the back wall. Don't be perplexed at all; the big picture is that we can accurately predict electron has passed from which of the slit(either A or B). But in this experiment electrons only show particle nature and form just two lines on the backwall. It seems like second entangled partner of electron which is detected(either by D3 or D4) send information to first one that observer knows the passage of electron and thus ensure particle nature.
Later on some additions were made in the experiment; Half silvered mirrors were placed in the paths of detectors which ensure 50 percent chance of reflection and 50 percent chance of transmission. After that a Quantum Eraser was used which means now electrons can be detected near detectors D1 and D2 too. when electrons were detected near D1 and D2 then there was no possibility to predict the passage of electron(which means we don't know electron has passed from which of the slits ). Now, in this case electrons show wave nature and form interference pattern on the back wall. It seems like second entangled partner of electron which is detected(either by D1 or D2) send information to the first one that observer doesn't know the passage of electron thus ensure wave nature.
This is very weird right! but the weirdest thing is that when second entangled partner send information to the first one, till that time first entangled partner has already collided with the wall. Inspite of this the alterations in the patterns on the back wall due to observance and non-observance indicates that electrons travel back in time and decide their behaviour accordingly.
Yeah, Quantum Physics is really very weird but nevermind; In future we might get our answers.
"QUANTUM PHYSICS MAKES ABSOLUTELY NO SENSE"
Monday, September 7, 2020
SCHRÖDINGER'S CAT EXPLAINED
In Classical Physics this UNIVERSE can be described with simplicity because If we study the past behaviour of an object then we can easily tell it's future behaviour. Moreover by it's present behaviour we can easily tell what would have happened to it in the past. for example- If we know the speed with which Earth is revolving around the Sun then we can easily tell, In which month Earth was/will be present at which position. In fact we can tell 2 yrs. ago It was present at which position.
But If talk about Quantum Physics, It completely changes our perspective to observe this UNIVERSE. In this we try to understand the behaviour of sub-atomic particles like- electrons, protons, photons,etc. Here we can't Predict the results of experiment before; If we repeatedly conduct the experiment, then too! . We know that Quantum Particles can be present at multiple Locations at a same time and can behave differently at a same time whiz believed to be Impossible in Normal world. we can't even Logically expect ourselves to be present and behave differently at different Locations.
That's why the Laws of Classical Physics are not applicable in Quantum Physics and the world described according to Quantum Physics can't be seen in Reality. Quantum Physics is considered as weird but Scientists believe that actual word can only be studied through Quantum Physics.
Today's Blog is about a Thought Experiment through which a Physicist known as Schrödinger described that, with Reference to bigger objects the Principles of Quantum Physics are weird and Pointless, this Experiment is Popularly known as Schrödinger Cat Experiment.
Many Experiments of Quantum Physics have proved that till when we don't observe the Quantum Particles, They exists in all the possible states of themselves at the same time which is known as Superposition state and as we observe them through any of the suitable instruments, their wave function collapses and a single possible state is selected from the treasure which becomes our Reality.
Our instruments can only see the state which is called "Result". Which means we can't tell the Result of the experiment without actually conducting it because we can get any of the possibilities as Result.
If it is true then it should be applicable on humans, animals, and everything that we can easily observe because they are also made up of Quantum Particles but we know that this is not true and every easily observable things are observed in a single state only! not more than one. for example- A car, either can be in rest or can be in motion at a time not can be in both rest and motion at a same time.
Schrödinger was not able to swallow this theory beyond his throat, which is also known as "The Copenhagen Interpretation". to showed Quantum Theory is Rubbish with Reference to Bigger Objects He take a count on a Thought experiment which is famous in the name of Schrödinger Cat Experiment.
In this experiment He trapped an Alive cat inside a Box, Along with the cat He also put a radioactive substance, a poisonous gas bottle, a hammer and a radioactive sensor in the box.
The radioactive substance was such that it's probability to decay was 50% and a hammer was attached to the radioactive sensor through a string and the poisonous gas bottle was put on the surface of box such that the heavier part of hammer was present just above to.
As the decaying of radioactive substance starts, sensor detect it and after that the hammer fall on the poisonous gas bottle resulting in death of the cat.
Till when the box is closed we don't know what is happening to the cat inside the box, is it Alive or Dead. And as we open the box, then only we can tell that the cat survived or not.
If we imagine cat as a Quantum Particle and apply the superposition principle then we can say that when box was closed and no one was observing the cat, then cat in the box exists in both of it's possible states. yes! there can be only two possible states only, either it is alive or dead which means at the same time the cat was alive and dead inside the box. when we open the box it's wave function collapses and one state is selected from two of it's possibilities and that state becomes our Reality.
That's the reason if we conduct this experiment repeatedly then every time we would get different outcomes or more specifically sometimes cat would be found Dead and sometimes it would be found Alive.
Our common sense says that when box was closed, at that time only either cat survived or lie dead.
If the cat was dead then after opening the box it would be dead only and if it survived it would appear alive to us but it is not possible that at a same time the cat was Alive and Dead both together.
which means it doesn't make any sense that if we observe it or not but Quantum Physics don't work according to our common sense. Infinite experiments proved that Quantum Particles don't rely on our thinking and always show weird behaviour, it behaves to an extent that in normal life we can't even think about it.
Many World theory is a very exciting theory which describe that "Every possibility comes to reality irrespective of the location, time and even Universe". which means that if Schrödinger's cat is found dead in this this Universe then it would have be found alive in another Universe. this theory explain it like this way, when box was closed then cat was in superposition state which means at that time it was dead and alive both together at a same time and when we open the box, A split happens in this Universe and because of that it's two copies are formed and amongst one of these cat would be found Alive and it would be found Dead in another one. If this theory would somehow proved to be true then it's implications would be Wonderful let us understand how:
Whenever Universe has the options then it forms number of copies of itself, where everything takes place that has a chance of happening. which means a world must be existing where Adolf Hitler had won the ww2, A world must be existing where Dinosaurs still exists and A world must be existing where Humans have developed a lot. Whatever Quantum Physics is wonderful and this world too.
Thursday, May 21, 2020
DOUBLE SLIT EXPERIMENT ?
To carefully observe and understand this phenomenon physicists set an observer machine which can detect the change in electron to a very small extent. When experiment was set up again the result turns the moral of scientists down, this time electrons form two single line patterns on the screen(whiz resemblance of particle nature).