Kind: captions
Language: en
what is quantum mechanics quantum
mechanics is the paradigm of physics
that came into being in the early part
of the 20th century that replaced
classical mechanics and it replaced
classical mechanics in a weird way that
we're still coming to terms with so in
classical mechanics you have an object
it has a location has a velocity and if
you know the location of velocity of
everything in the world you can say what
everything's gonna do quantum mechanics
has an aspect of it that is kind of on
the same lines there's something called
a quantum state or the wave function and
there's an equation governing what the
quantum state does so it's very much
like classical mechanics the wave
function is different it's sort of a
wave it's a vector in a huge dimensional
vector space rather than a position in a
velocity but okay that's a detail and
the equation is the Schrodinger equation
not Newton's laws but okay again a
detail where quantum mechanics really
becomes weird and different is that
there's a whole nother set of rules in
our textbook formulation of quantum
mechanics in addition to saying that
there's a quantum state and it evolves
in time and all these new rules have to
do with what happens when you look at
the system when you observe it when you
measure it in classical mechanics there
were no rules about observing you just
look at it and you see what's going on
that that was it right in quantum
mechanics the way we teach it there's
something profoundly fundamental about
the act of measurement or observation
and the system dramatically changes its
state even though it has a wave function
like the electron in an atom is not
orbiting in a circle as sort of spread
out in the cloud when you look at it you
don't see that cloud when you look at it
it looks like a particle with a location
so it dramatically changes its state
right away and the effects of that
change can be instantly seen and what
the electron does next so that's the
again we need to be careful because we
don't agree on what quantum mechanics
says that's why I need to say like in
the textbook view etc right but in the
textbook view quantum mechanics unlike
any other theory of physics places uh
gives a fundamental role to the act of
measurement
you