II' Quantum Tornadoes Near Absolute Zero

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II. Quantum Tornadoes Near Absolute Zero
Paul C Haljan University of Michigan October 2004
Courtesy NOAA
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JILA, University of Colorado
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Ivan
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Courtesy NOAA
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How about rotation in Quantum fluids
?..those governed by Quantum Mechanics ....
Y
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Bose Einstein condensation (BEC)

• Quantum mechanics
• Indistinguishability of particles
• (bosons)

• 1925 predicted by A. Einstein,
  based on work by S. N. Bose

S.N. Bose
A. Einstein
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Macroscopically occupied quantum states. (Neat
Stuff!)
e
Superconductivity
no resistance
Superfluid helium
no viscosity
Laser
coherent energy
Gaseous BEC
???????
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At high temperature ...
A gas of atoms - billiard balls
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At low temperature ..
d
Ldb position uncertainty or de Broglie
wavelength h/mv (larger for lower temperature)
d - particle spacing (smaller for higher
density)
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Very cold .
Overlapping deBroglie waves of indistinguishable
particles (bosons)
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then quickly near the critical temperature .
BEC
A giant matter wave A large fraction of the
atoms in the lowest energy state
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Forbidden science!
What we want deBroglie waves to overlap.
Requires high density or low temperature
But dont want particles to crystallize!
So need a low density . thus a large de Broglie
wavelength, thus very low temperature.
NO!
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Rubidium at room temperature
Where we start .
Vaporize to make a gas .
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Rb
A
Laser
Pushing atoms with light laser cooling
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Magnetic trapping and evaporative cooling
??B
Appletsmagnetic trapping, evaporation
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vapor cell MOT
magnets
diode lasers (cheap)
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BEC intro II
JILA Mark III
BEC
Commissioned 1996 a BEC every 60 seconds Nearly
1million produced so far
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Shadow snapshot of BEC
CCD array (TV camera)
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BEC
50 nK
2 D velocity/density distributions
200 nK
400 nK
0.2 mm
JILA 1995
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So what is Bose-Einstein Condensation really
like, anyway?
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what its not ..
A typical phase transition - due to attractive
forces between (water) molecules
BEC transition doesnt require this Einstein(1925)
condensation without attractive forces
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COLD
One million times colder than liquid Helium
Thin
One million times less dense than air at STP
Gelatinous
It wiggles. It jiggles.
Coherent
This gets a little hard to explain
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Rotation
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Classical rotation

• Gently spin up a classical fluid
• by rotating its bucket .
• Q What form does the fluids
• rotation take?

Bucket rotation
A Rigid body rotation (like a record on a
record player)
No shear forces in the fluid since all the fluid
rotates together!
Rotating bucket demo
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Quantum superfluid rotation
Rigid body rotation forbidden!
OK so say I make a really deformed bucket and
rotate it ..
Rotate
Surely the fluid has to rotate then !
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Well no .
Bucket rotation
It irrotationally deforms to follow the bucket
walls!!!!
Belt demo
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But if the bucket rotates fast enough
. Vortices can be nucleated at the walls, -
quantized vortices
BEC
core
rotation
300 mm
classical vortex Mitch (circulation l many
quanta )
Bozy ( l 1) also 2, 3, 4, .
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Quantized vortex circulation occurs for the same
reason why electron orbitals are quantized in a
hydrogen atom Wavefunctions!
l3
p
l7
p
Only certain electron wavelengths fit on the
circle. The fundamental and its overtones ..
1,2,3,4,
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Strong shear flows since the air rotates ever
faster towards the eye
Tornado bottle
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http//www.quantumbalancing.com
Water Vortex MagnetizerImproves the taste,
quality, and vitality of water!
new natural pattern of vortex magnetic
implosion energies are applied.
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Vortex physics
Superfluid 4He, rotating bucket
Magnetic flux lattice
Bell Labs
Optical vortices
E. J. Yarmchuk, M. J. V. Gordon, R. E.
PackardPhys. Rev. Lett. 43, 214 (1979)
Scheuer, OrensteinScience 285, 230 1999
Vortex... result of a tremendous circulatory
energy phaseout. This phaseout is responsible for
a certain revolution of a cycle that produces
manifestation.
-God Thor, Universe of Estasia
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Superfluid and vortices in a neutron star ?!!!!.
Max Camenzind
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Making Vortices in a BEC
First spin up a normal gas in a magnetic bucket
W
Magnetic bucket
y
x
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Then cool it . with a special kind of forced
evaporation.
Remove hot atoms near the axis of rotation
Leave the fast rotating edges of the gas alone
The gas is cooled .. .. and spun up to gt97 of
the centrifugal limit!
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Making a highly-rotating BEC
2.65 MHz
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Making a highly-rotating BEC
2.60 MHz
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Making a highly-rotating BEC
2.58 MHz
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Making a highly-rotating BEC
2.57 MHz
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Making a highly-rotating BEC
2.55 MHz
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Making a highly-rotating BEC
2.5 MHz
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Making a highly-rotating BEC
2.4 MHz
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Making a highly-rotating BEC
2.35 MHz
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Making a highly-rotating BEC
2.35 MHz
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Static and rotating BECs by eye
Static
z
Rotating
Side View
60 um
80 mm
y
x
Also meniscus curvature of superfluid He II
Osborne (1950), Meservey (1964)
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A beautiful example of The quantum - classical
correspondence principle
WLattice
WBEC
Effective rigid body rotation like a classical
fluid
Many vortices (quanta of rotation)
Classical
Quantum
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A crystallized vortex lattice . why?
A like vortices repel one another
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Kinda like a crystal of atoms
STM image of Platinum atoms
IBM corp.
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Vortices interact ..
Hubble Image
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A nice example of vortex interaction smoke
rings!
LOWER

AIR
HIGHER PRESSURE
-
Outward force counteracts vortex attraction
LOWER PRESSURE
Vortex ring cannon
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So perfect . just begging for .
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Shocking the BEC with a poking beam
10 msec
20 msec
5 msec
15 msec
Cornell group JILA
35 msec
25 msec
30 msec
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Tkachenko modes
t0.5 s
t1.65 s
Transverse bending caused by Coriolis forces
Cornell group JILA
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Giant vortex formation
Laser power 60 fW, laser continuously on
0 sec
0.25 sec
0.9 sec
2 sec
Laser blasts atoms out of the middle of
the condensate ..
W
Cornell group JILA
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Vortex team, past and present B. P. Anderson I.
Coddington P. Engels J. Ensher P.C.H. D. S.
Hall M.R. Matthews V. Schweikhard S.-K. Tung
Eric A. Cornell
JILA, University of Colorado
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Next week
Cd
Cadmium quantum bits
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