A Quantum Journey

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A Quantum Journey

• Quantum Physics And Quantum Physicists

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Classical Physics
All of physics excluding relativity and quantum
mechanics
Two distinct ideas in classical physics
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Classical Physics Walks The Planck
A black body radiator produces a spectrum
characteristic of its temperature
Predicted an ultraviolet catastrophe
Classical Physics had failed
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Classical Physics Walks The Planck
Max Planck spotted the problem
Energy is not continuous
There is a natural limit to the short wavelength
radiation
E hf
Energy and waves come in quanta
Waves must be made of particles
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Energy, Mass And A Famous German
annihilate
Two photons produced
Mass (particles) converted to Energy (waves)
Reverse process Energy can be converted to mass
Energy and mass can be interchanged
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Energy, Mass And A Famous German
Albert Einstein quantified this relationship
E mc2
Mass and energy are just different forms of the
same thing
ANY gain in energy is a gain in mass (and
vice-versa)
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WaveParticle Duality
Louis-Victor de Broglie combined Einstein and
Plancks equations
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WaveParticle Duality
All quantum entities have both particle and
wave-like properties
LIGHT
A wave when propagating through matter / space
Particles when interacting with matter
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Uncertainty
You cannot measure both momentum and position at
the same time
This is called Heisenbergs Uncertainty Principle
This is NOT due to any limitations of measuring
apparatus
An electron doesnt have a precise position and
momentum at the same time
We cannot know, as a matter of principle, the
present in all its details.
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The Experiment With Two Holes
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The Experiment With Two Holes
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The Experiment With Two Holes
An electron behaves like a wave, producing an
interference pattern
But electrons appear as particles (dots) on the
screen
Slowing down to one electron at a time produces
the same pattern
Electrons must have an awareness of past and
future
If we look at each electron, we can see which
hole it went through, but we must disturb the
electrons to do this
The pattern for particles is produced
Electrons must go through both holes at the same
time
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The Copenhagen Interpretation
In taking any measurement we must disturb what we
are measuring
It is meaningless to ask what quantum entities
are doing when we are not looking at them they
exist as a superposition of states
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The Copenhagen Interpretation
In taking any measurement we must disturb what we
are measuring
It is meaningless to ask what quantum entities
are doing when we are not looking at them they
exist as a superposition of states
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Schrödingers Cat
The cat will be both dead and alive until
somebody looks
The Copenhagen interpretation is absurd
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The Transactional Interpretation
Every charged particle in the universe knows what
is happening to every other charged particle
The particle must decide which handshake wave to
accept
This is given by the laws of probability
Gives the same predictions as the Copenhagen
interpretation but gives a different perspective
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Conclusion
Planck showed that energy occurs in quanta