Download Copenhagen Interpretation

Quantum Mechanics
& the Nature of
Matter, Motion
and Reality
Erwin Schroedinger : 1926
y
Describes the mechanics of electron behavior
within (and outside of) atoms.
e-
MEASUREMENT SCREEN
Electron Double Slit Experiment
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MEASUREMENT SCREEN
Electron Double Slit Experiment
e-
MEASUREMENT SCREEN
Electron Double Slit Experiment
e-
MEASUREMENT SCREEN
Electron Double Slit Experiment
e-
MEASUREMENT SCREEN
Electron Double Slit Experiment
e-
MEASUREMENT SCREEN
Electron Double Slit Experiment
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
Electron Double Slit Experiment
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
1926 : Bourne Interpretation
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
1926 : Born Interpretation
y
1926 : Born Interpretation
A Schroedinger wave function
describes the PROBABILITY of
a measurement returning
certain results.
y
1926 : Born Interpretation
A Schroedinger wave function
describes the PROBABILITY of
a measurement returning
certain results.
???
y
1926 : Born Interpretation
12
11
10
9
1/36
2/36
3/36
4/36
8 6/36
7 10/36
6 16/36
5
4
3
2
4/36
3/36
2/36
1/36
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
1926 : Born Interpretation
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
1926 : Born Interpretation
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
1926 : Born Interpretation
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
1926 : Born Interpretation
How does the spread out electron
wave collapse to a single point
upon measurement by
the screen?
e-
MEASUREMENT SCREEN
1926 : Born Interpretation
y
1926 : Born Interpretation
?
?
?
?
?
?
?
1925 : Heisenberg’s Matrix Mechanics
Formulates a mathematical description of
the atom which completely rejects any
non-measurable reality.
1925 : Heisenberg’s Matrix Mechanics
Formulates a mathematical description of
the atom which completely rejects any
non-measurable reality.
Uncertainty Principle
There exist paired quantities…
the combined uncertainty
of which will remain
above a set level.
MOMENTUM
vs. POSITION
ENERGY CONTENT
vs. TIME
(Δp?)(Δx?) > h/4p
The Copenhagen Interpretation
Wave-functions describe the existence of
probabilistic mixtures of physical quantities.
Any reality ascribed to nature beyond this is
false conjecture.
1927 : Fifth Solvay Conference
- Brussels
1927 : Fifth Solvay Conference
- Brussels
Schroedinger
Compton deBroglie Heisenberg
Born
Planck
Curie
Lorentz
Einstein
Bohr
The Copenhagen Interpretation
A Schroedinger wave function
describes the PROBABILITY of
a measurement returning
certain results.
e-
Einstein’s Objection
The electron’s path must be
deterministic and hidden… the
quantum theory must be
INCOMPLETE.
e-
Einstein’s Objection
The electron’s path must be
deterministic and hidden… the
quantum theory must be
INCOMPLETE.
e“However… I am not
convinced. God does
not play dice.”
Einstein vs. Bohr
Einstein vs. Bohr
Einstein-Podolsky-Rosen Paper : 1935
EPR Paradox : 1935
EPR Paradox : 1935
• Quantum mechanics is
incomplete.
• Demanded a world of
real, deterministic,
local physics.
EPR Paradox : 1935
• Quantum mechanics is
incomplete.
• Demanded a world of
real, deterministic,
local physics.
INTERACTION
position = 12
momentum = 9
EPR Paradox : 1935
• Quantum mechanics is
incomplete.
• Demanded a world of
real, deterministic,
local physics.
Property A
position: 10
momentum: ?
INTERACTION
position = 12
momentum = 9
Property B
position: ?
momentum: 3
EPR Paradox : 1935
• Quantum mechanics is
incomplete.
• Demanded a world of
real, deterministic,
local physics.
Property A
position: 10
momentum: ?
INTERACTION
position = 12
momentum = 9
Property B
position: ?
momentum: 3
?
• Instantaneous communication would be necessary.
EPR Paradox : 1935
• Quantum mechanics is
incomplete.
• Demanded a world of
real, deterministic,
local physics.
Property A
position: 10
momentum: ?
INTERACTION
position = 12
momentum = 9
Property B
position: ?
momentum: 3
?
• Instantaneous communication would be necessary.
• Requires the existence of local interaction only.
• If QM is correct… non-local interaction must be real.
Bell’s Inequality: 1964
Property A
position: 10
momentum: ?
INTERACTION
position = 12
momentum = 9
Property B
position: ?
momentum: 3
?
• Bell’s Theorem provides a manner in which to test for
the existence of EPR hidden variables.