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Visuals: Unit 6

Animations

BCS Pairs
The stronger the attraction between pairs, the greater the resistance of the pairs to breaking apart.
Behavior of Bosons and Fermions
The quantum mechanical behavior of bosons is always to do the same thing. The quantum mechanical behavior of fermions is never to do the same thing.
Bosons to BEC
When a gas of bosons is cooled to an extremely low temperature, bosons create a new state of matter—a Bose-Einstein Condensate or BEC.
Cooling a Gas of Fermions
A gas of fermions is cooled and the motion of the atoms in a trap is quantized. There is quite a bit of kinetic energy in that gas even at low temperatures.
Cooper Pairing
Unlike Jin's initial Fermi condensate, there is a different kind of pairing involved with superconductors called "cooper pairing."
Cooper Pairing and Superconductivity
One electron moving in one direction and one electron moving in the opposite direction somehow move in some correlated way.
From Fermions to BEC
In Jin's achievement of a Fermi condensate, the key breakthrough was coercing individual fermionic atoms to pair together creating bosonic molecules.
Scanning Tunneling Microscope
An electric voltage is applied between the microscope tip and the sample. Measuring the current can reveal quantum mechanical features of the sample.
Standard vs. Super Conductors
In a typical copper cable, there's resistance. In a superconductor, when you send electrons in one end, they come out the other end with no energy loss.
Superconductor Properties
Superconductors are materials with two essential properties: They have zero resistance and expel magnetic fields.
Superfluid Fountain
A fountain of superfluid 4He.
Timeline of Type I and Type II Superconductors
The first (Type I) superconductors were cooled at least to 30 Kelvin. In 1986, a new class of high-temperature superconductors (Type II) was found.
Type I and Type II Superconductors
Type I superconductors expel the magnetic field uniformly. Type II allow the magnetic field to penetrate in quantized packets called "vortices."
Vortices
Unpinned vortices can move, forming a regular pattern in the STM images. Pinned vortices are scattered irregularly throughout the image.

Photographs

BEC Vortices
The formation of vortices in this BEC shows that it is a superfluid.
Cotton Ball Model
A cotton ball model of an atom.
Magnetic Resonance Imaging
Superconducting magnets enable MRI machines to produce dramatic images.
Mendeleev and Lewis
The father and son of chemical periodicity: Dmitri Mendeleev and Gilbert Newton Lewis.
Plum Pudding Model
Plum pudding (or raisin scone) model of the atom.
Stern-Gerlach Experiment
The Stern-Gerlach experiment demonstrated that spin is quantized.

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Graphics

BEC Oscillations
Super-oscillations of a quantum gas and their dissipation on heating.
blackbody spectra
Blackbody Spectra
The spectrum of blackbody radiation at different temperatures.
Bose Condensate
Atoms in a Bose condensate at 0 K.
Some of the first experimental evidence for a gaseous macroscopic quantum state.
Bose-Einstein Condensation
Some of the first experimental evidence for a gaseous macroscopic quantum state.
Some of the first experimental evidence for a gaseous macroscopic quantum state.
Bose-Einstein Condensation
Three stages of cooling, and a quantum phase transition to a BEC.
Atoms in a trap at 0 K: bosons form a BEC (left) and fermions form a degenerate Fermi gas (right).
Bosons and Fermions
Atoms in a trap at 0 K: bosons form a BEC (left) and fermions form a degenerate Fermi gas (right).
While the complex part of a quantum wavefunction
Complex Quantum Wave
While the complex part of a quantum wavefunction "waves," the probability density does not.
Composite Fermions and Bosons
Protons in LHC collisions (left) and electrons in a superconductor (right) are examples of composite fermions and bosons.
Diffraction of green laser light passing though a random medium.
Diffraction in Random Media
Diffraction of green laser light passing though a random medium.
Early Periodic Table
An early version of Mendeleev's Periodic Table, showing the positions of missing elements.
The ground state of helium: energy levels and electron probability distribution
Ground State of Helium
The ground state of helium: energy levels and electron probability distribution.
The two isotopes of helium: a boson and a fermion.
Helium Isotopes
The two isotopes of helium: a fermion and a boson.
Interference of two coherent BECs, separated and allowed to recombine.
Interfering Bose-Einstein Condensates
Interference of two coherent BECs, separated and allowed to recombine.
Lewis Shell Model
The Lewis shell model for the first three atoms in the modern periodic table.
Electrons in atomic energy levels for Li, Na, and K.
Li, Na, and K Energy Levels
Electrons in atomic energy levels for Li, Na, and K.
Molecular BEC interference
Interference pattern created by the overlap of two clouds of molecular BECs, each composed of 6Li2 diatomic molecules.
Multiwavelength Milky Way
Our galaxy, imaged at many different wavelengths.
Nuclides
As this chart shows, not every imaginable nucleus is stable.
Bohr's classic helium models
Oscillating Model of Helium Atom
A simple classical model fails to explain the stability of the helium atom.
Quantum Vortices
Quantum vortices in a BEC (top) and the corresponding phase of the quantum wavefunction (bottom).
Rutherford's Hydrogen Atom
Rutherford's model of a hydrogen atom.
Shell Model for Molecules
Molecules in the Lewis shell picture: the pair bond for H2 and Li2.
Soliton
Density notch soliton.
Spin Pairing in Molecules
Spin pairing in the molecules H2 and Li2.
Temperature and the de Broglie Wavelength
Atomic de Broglie waves overlap as temperatures are lowered.