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Hi, everybody. 
And welcome to the first lecture in our 

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course Exploring Quantum Physics. 
Today, I will introduce the main 

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formulation of quantum theory using 
Schrodinger. 

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And I will also tell you a little bit 
about a fascinating history of the 

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subject. 
But before going to this main part, I 

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would like to talk about the process of 
learning quantum physics. 

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And about why I think, so many people 
find it difficult and frustrating. 

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And I hope that this brief discussion 
will help you avoid this frustration, and 

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make the process of learning quantum 
physics here more effective. 

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Richard Feynman doesn't really need an 
introduction. 

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He was one of the heroes and legends in 
physics, universally recognized as a 

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genius. 
He was also a great speaker and 

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enthusiastic popularizer of physics. 
In 1979, he gave a series of very 

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interesting lectures on quantum physics 
at the University of Auckland in New 

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Zealand. 
They're actually available on YouTube 

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online and I would encourage you to 
listen to them. 

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If you do so, you will see that Feynman 
spends 30 or so, minutes in the beginning 

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of his first lecture to prepare the 
audience for what they were going to hear 

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next. 
In one of the main messages of this 

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introductory part was that no matter what 
Feynman was to do, the audience wouldn't 

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be able to understand Quantum Mechanics 
anyway. 

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That he talks about physics students and 
physics professors and their level of 

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understanding of Quantum Physics. 
Let's listen to what Feynman had to say 

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in this regard. 
if I'm going to explain this theory, the 

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question is, are you going to understand 
it? 

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Will you understand the theory? 
When I tell you first that the first time 

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we really thoroughly explain it to our 
own physics students is when they're in 

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the third year graduate, graduate 
physics. 

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Then, you think the answer is going to be 
no. 

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And that's correct, you will not 
understand. 

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 >> [LAUGH] . 

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 >> But this business about not understanding 

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is a very serious one that we have 
between a scientist and an audience. 

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And I want to be at work with you, 
because I want to tell you something. 

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The students do not understand it either. 

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 >> [LAUGH]. 

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 >> And that's because the professor doesn't 
understand. 

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 >> [LAUGH]. 

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 >> This is not a joke, but very interesting. 

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 >> So, what Feynman seems to be saying is 

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that nobody, not even professional 
physicists, not even himself perhaps, 

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really understand quantum physics. 
Well, this is probably the last thing you 

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want to hear before starting this course. 
But this is strictly not my intention to 

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give you the impression that you should 
give up without even trying. 

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On the contrary, I'd like to speculate 
what I think Feynmam might have meant 

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there. 
But why I think so many people find it 

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difficult to study quantum physics and 
other advanced physic subjects. 

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And I hope that this discussion will help 
us further down the road when we 

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encounter unusual counter intuitive 
quantum phenomena. 

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Let us look at quantum mechanics from the 
perspective of all major physics theories 

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out there. 
In this slide, I attempt to present all 

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these theories in a single diagram, 
which, of course, is an unrealistic sort 

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of silly task. 
And so, the result I should, I cannot, I 

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shouldn't be taken too seriously. 
What we have here are three axis, 

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labeling fundamental physics constants. 
So, here, I have an the inverse speed of 

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light. 
this constant G is the gravity constant, 

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which appears in the Newtonion gravity. 
And along the horizontal axis, I have the 

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Planck constant. 
We show, as we show, c is the most 

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important fundamental constant that 
appears in quantum mechanics and that it 

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relates the particle and wave properties. 
Now, the red dots in this diagram 

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represent, symbolically, major fields of 
physics. 

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For example, on this line, I have two red 
dots. 

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So, the one which has all, agree, 
responds to all physical constants being 

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zero is just kinematics or classical 
mechanics. 

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Essentially, 17th century physics. 
So this dot here, with the finite gravity 

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constant, but all other constant. 
0 is the Newtonian Gravity. 

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Now, moving up, the vertical axis, to the 
finite speed of light, brings us to a 

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theory which takes into account this 
finite speed with which, with which 

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interactions propagate. 
And this is the celebrated Special 

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Relativity Theory of Einstein. 
Combining it with gravity results in 

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General Relativity, another celebrated, 
another very famous geometric theory of 

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Einstein. 
Finally, moving along the horizontal axis 

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to find a Planck's constant, brings us 
to, actually, the subject of our course, 

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non-relativistic quantum mechanics. 
So, the results of this part, which we 

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are not going to discuss too much in this 
course, which combines the relativistic 

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effects and the quantum mechanical 
effects. 

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And this is, so called Quantum Field 
Theory or Quantum Electrodynamics. 

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They are more complicated theory. 
Actually, I could have added here another 

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dot which has all fundamental physics 
constants. 

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This is this would be theory of 
everything. 

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It doesn't really exist yet but everybody 
wants to get it. 

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So, this has been one of the holy grails 
of physics for many years. 

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Now going back to learning quantum 
physics and what does it all have to do 

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with it. 
so let us discuss what theory governs our 

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everyday lives. 
What is sort of our comfort zone? 

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And I would claim that we are somewhere 
here in this area. 

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Certainly, the life skills that we 
encounter in our everyday lives are much 

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larger than atomic. 
The velocities are certainly much smaller 

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than the speed of light. 
And well, we do experience gravity on a 

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daily basis. 
So, we're somewhere here. 

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And here is also where our intuition 
works. 

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And if we say, we understand something, 
what we usually mean by that is that we 

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can relate a phenomenon to another 
phenomenon that occurs here in this area. 

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So, for example, if we were to say that 
we really understand quantum mechanical 

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effect, it would often times imply that 
we would have found a way to relate it by 

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something that we all ready know here. 
But the problem with all this advanced 

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physics subjects, especially with quantum 
physics, is that such a mapping, such a 

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relation is not always possible. 
In other words, it's not always possible 

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to meaningfully project quantum 
mechanical phenomena on this classical 

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axis. 
And if no classical analog exist, this is 

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what we call strange. 
And this is what we find difficult. 

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But on the other hand, if we were to 
imagine a fictitious civilization of tiny 

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species that lived on atomic scales 
somewhere in this area. 

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So, this guys would have had really a lot 
of problems understanding our classical 

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work. 
So, the problem is not really with the 

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quantum physics itself but with our 
centristic position on how we want to 

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understand it. 
But now, how do[UKNOWN] quantum physics 

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if we can't really regularly understand 
it at intuitive level. 

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Fortunately, there is a way to do so. 
By speaking in common language of all 

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physic theories, that is not rooted in 
and is independent of our classical 

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world. 
And this is, of course, mathematical 

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formalism that needs to be developed. 
And it may turn out that two seemly 

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unrelated phenomena, lets say, on the 
classical side and on the quantum side, 

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may be explained by similar differential 
equations or something like that. 

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And by studying those, we can develop 
intuition about something which is 

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otherwise, inaccessible to us. 
But after this discussion, you may ask, 

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why bother studying quantum physics if 
it's not really relevant to our everyday 

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lives? 
So, the modulation comes from 

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experiments. 
And more recently, also from ecological 

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advances that creates systems and 
devices, which operate further, on the 

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right of this axis. 
The take home message here, is that when 

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you study quantum physics or any other 
advanced physics subject, for this 

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measure, you should actually be prepared 
to encounter phenomena that may appear 

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bizarre at the first sight. 
And that you may find difficult to 

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understand. 
When it does happen don't panic and 

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certainly don't drop the course because 
of that, and don't assume that others 

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find these things obvious. 
It's certainly not the case. 

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so, I think the best way to understand 
such new concepts is first, understand 

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experimental data that support them. 
And then, develop or understand a 

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mathematical formalism and the proper 
theory that describes these phenomena. 

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So, when you use this theory again and 
again, you will develop your own 

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intuition and get the feeling about a 
deeper understanding of the subject. 

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So, speaking about the mathematical side, 
so I should mention that of course 

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quantum mechanics is a demanding subject. 
And it, we will have to use certain vast 

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mathematical techniques. 
But there will be lectures with different 

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sort of levels of mathematical 
sophistication. 

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Some of them will be pretty advanced, 
some of them actually won't use much math 

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at all. 
And so, I, I hope that all of you with, 

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with different backgrounds in different 
levels of mathematical preparation will 

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find something that is useful and 
interesting.