Dr. Jeffrey Guest

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Cooling and Trapping Atoms with Light Atomic
Clocks and Atom Lasers
Fingerprints of quantum mechanics
Dr. Jeffrey Guest University of Michigan
Saturday Morning Physics, November 9th, 2002
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Cooling and Trapping Atoms with Light Atomic
Clocks and Atom Lasers
Fingerprints of quantum mechanics
The coldest place in the universe
Making waves, slowing light, and keeping time
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(No Transcript)
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Atomic and Optical Physics
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Our two players
Atomic particles
Electromagnetic waves
applet
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A Mystery Unfolds
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Blackbody Radiation
Statistical Mechanics a counting game
of possible electromagnetic guitar strings per
unit frequency? n2
Classical Physics Energy kT into all guitar
strings
Quantum Physics 1900 Energy comes in units hn
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M100 Hubble wide field planetary camera 1
www.cosmicshell.com/miranda/lab/BBradiation/BBrad
iation.html
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COBE T 2.735 K in all directions (to one part
in 100,000)
http//www.damtp.cam.ac.uk/user/gr/public/cmbr_hom
e.html
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Problems with the Classical Atom

• According to Thompson, Rutherford
• Atom is mostly empty space
• Electrons ORBIT the nucleus

BUT there are problems with this scheme
applet
Accelerating charges emit electromagnetic
radiation, lose energy, spiral in and
collapse!? Classical atom NOT stable!
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Whats going on? The Bohr Atom
Ultraviolet
Infrared
Frequency
Hydrogen
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Schrodinger Wave Mechanics
Combined with the Pauli exclusion principle and
electron spin, the Schrodinger equation predicts
the structure of all atoms
Measurement leads to a collapse of the
wavefunction, leading to indeterminacy and
nonlocality in quantum mechanics.
Wave-nature extends to ALL particles, including
the entire atom. This wave-nature leads to
uncertainty and interference.
Quantum Electrodynamics is the most accurate
theory known to mankind, predicting measurements
to a part in a billion.
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Next week!
The coldest place in the universe
It might not be obvious when you step outside on
a sunny day, but light packs a punch. It knocks
around massive particles as dramatically
demonstrated in the tails of comets. Using
lasers and magnetic fields, physicists are now
using that punch to slow down, trap, and
ultimately cool atoms to temperatures closer to
absolute zero than anywhere else in the known
universe.
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Atom - Photon Interactions
Ultraviolet
Visible
Infrared
Frequency
Hydrogen
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Fingerprints of Quantum Mechanics

• Atomic and Optical Physics in the scheme of
  things
• Before Quantum Mechanics Electromagnetism and
  the atom
• Fingerprints
• Problems with the Blackbody model
• Problems with the atom
• Wave Mechanics