- Einstein is celebrated for giving us
the special theory of relativity.
The fact that nothing goes faster than light,
time is the fourth dimension,
but he didn't come up with the equations.
That was the interpretation,
the narrative of the equations,
and it's the same with any other theory in physics.
With quantum mechanics, it's different.
We have the equations of quantum mechanics,
but we can't agree on what that equation means.
Schrodinger's equation being the most famous one,
we can crank the handle
and produce numbers from the equation,
but the narrative, the story, the explanation
is still something that we are arguing about.
And that bugs me.
By the end of the 19th century,
it was already known
that we needed some new physics
to explain mysterious phenomena-
X-rays-like radio activity,
that energy seemed to be coming out of nowhere,
to understand the behavior or the structure of the atom,
and so when quantum mechanics came along,
it wasn't because physicists were sitting,
scratching their heads thinking,
"There must be some deeper understanding
of the nature of reality.
I know, let's come up with quantum mechanics."
It was forced on physicists
because of experimental results that were inexplicable.
It's a fuzzy, probabilistic world.
Things are never behaving in one way for certain,
atoms can have two energies at the same time,
electrons can be in two places at the same time,
particles aren't discreet, little lumps,
they can sometimes behave
like spread-out waves of probability.
It's really down at a level
far beyond anything that we can visualize or imagine.
If we think about everyday objects,
a tennis ball, for example,
subject to the laws of Newtonian mechanics;
you drop down, orders of magnitude,
down to a millimeter,
down to a micrometer,
down to the scale of individual cells or bacteria,
ultimately, when you get down
to something like a billionth of a meter,
then you start to encounter the fuzziness
of the quantum world.
The founding fathers of quantum mechanics in the 1920s,
people like the Danish Physicist, Niels Bohr,
Werner Heisenberg, Wolfgang Pauli-
and they realized they could make predictions
for the results of measurements,
but you only make the connection with the real world
if you look.
So that's how they got away with not needing a narrative,
the 'shut up and calculate interpretation,'
more correctly, it's known as the 'Copenhagen narrative.'
But now, many physicists, including myself,
argue that it's not a narrative at all,
it's a bury your head in the sand approach.
Einstein was very unhappy about this, by the way,
he said, "No, look, the job of physics is to know
and understand how the world is,
not just to make predictions
about the results of experiments
and that sort of operationalist view.
Well, fine, that's useful
but that doesn't give us real understanding."
That's why we still need a narrative.
The knowledge of quantum mechanics
together with Einstein's theories of relativity
really gave us the modern world.
We wouldn't have developed understanding of materials
and how they conduct electricity,
so we wouldn't have understood semiconductors,
we wouldn't have developed silicon chips,
therefore, we wouldn't have computers.
I wouldn't be talking here in this medium today
were it not for our quantum understanding.
But there are aspects of the quantum world
that are more mysterious.
Quantum entanglement, for example,
the idea that, let's say,
two electrons that are separated in space
can nevertheless somehow behave in a coordinated way.
There are speculative ideas
about whether space itself is connected together
via quantum entanglement.
We don't all need to be experts in quantum mechanics,
not even the smartest quantum physicists
knows how stuff goes on inside their smartphone,
but, we are going to be developing ideas
like quantum cryptography, quantum computing,
quantum sensors-
these are ideas and technologies that are going to affect us
in our daily lives,
so we do need to have enough of an appreciation
of the science simply to know
what to trust,
who to trust.
As we peel back layers of the onion
about the nature of reality,
we find deeper mysteries inside.
But it's also true that we are learning more,
we are becoming more enlightened,
we know a lot about how the world works now,
but that doesn't mean we have reached the end of the road.
No, I think there's gonna be more weirdness coming
down the line and that's great.
I look forward to it.