2234-5
Meeting of Modern Science and School Physics: College for School
Teachers of Physics in ICTP
27 April - 3 May, 2011
Quest to absolute zero and Bose condensation
Alexandre Bouzdine
University of Bordeaux
France
QUEST TO ABSOLUTE ZERO AND BOSEEINSTEIN CONDENSATION
A. Buzdin
Condensed Matter Theory Group, University of
Bordeaux I
and Institut Universitaire de France
Meeting of Modern Science and School Physics,
ICTP, Trieste, Italy
27 April - 3 May, 2011
1
kB= 1.3806504×10 JK
"'+ !!
First thermometers - thermoscopes
2
First thermometers - thermoscopes
Galileo Galilei (1564 1642)
Thermometers
4
'%
)#"%
100°C
$(
0°C
&"
5
Temperature scale
core of sun surface of sun L N
2
106
103
L He
room
temperature
1
3He
sub-Doppler
superfluidity
cooling
10-3 MOT
10-6
typical TC
of BEC
2003 MIT
Na BEC
10-9
0
(K)
By 1845, Michael Faraday had managed to liquefy most
permanent gases then known to exist.
In 1877, Louis Paul Cailletet (18321913) in France
and Raoul Pictet (18461929) in Switzerland
succeeded in producing the first droplets of liquid
air.
Nitrogen was first liquefied at the
Jagiellonian University on 15 April 1883 by
Polish physicists, Zygmunt Wróblewski
and Karol Olszewski.
7
Quest to liquefy Helium
Helium-4 was first liquefied on
10 July 1908 by Dutch physicist
Heike Kamerlingh Onnes.
Properties of
liquid helium
Helium-4
Helium-3
Critical
temperature[
5.2 K
3.3 K
Boiling point at 1
4.2 K
atm[
3.2 K
Minimum melting
25 atm
pressure
29 atm at 0.3 K
Superfluid
transition
temperature at
saturated vapor
pressure
1 m K in zero
magnetic field
2.17 K
8
Physics of low temperature was born !
cosmic microwave background radiation
has a thermal black body spectrum at a temperature of 2.725 K
Arno Allan Penzias and Robert Woodrow Wilson
We may have the temperature below 2.7 K only in our laboratories.
10
1911: discovery of superconductivity
Discovered by Kamerlingh Onnes
in 1911 during first low temperature
measurements to liquefy helium
Whilst measuring the resistivity of
resistance dropped to zero at 4.2K
In 1912 he found that the resistive
state is restored in a magnetic field or
at high transport currents
1913
Phase
diagram of
He
12
1937: Superfluidity of liquid He4
Piotr Kapitza
1978
14
Rotaion of
superfluid:
vortices
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15
(#%('*!$(
David M. Lee, Douglas Dean
Osheroff and Robert C. Richardson
1996
2003
Antony Legget
17
1000 K
100 K
10 K
1K
0.1 K
Laser cooling
Chu, Cohen-Tannoudji et
Phillips Nobel Prize 1997
"for development of methods
to cool and trap atoms with
laser light".
0.01 K
1 mK
0.1 mK
0.01 mK
1 K
0.1 K
0.01 K
Laser light
10-100 microkelvin
= 0.00001 - 0.0001 K
1 nK
demo
19
20
h
2 mkT
21
World of Quantum Mechanics
Wave nature of matter, interference, tunneling, resonance
h
2 mk B T
~1"m for Na @ 100nk
Quantum statistics
Uncertainty principle, zero-point energy
Quantum phase transition
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Bose-Einstein condensation of
weakly interacting atoms
Typical distance between atoms
Typical scattering length
300 nm
10 nm
Scattering length is much smaller than characteristic interparticle distances.
Interactions are weak
Atomic gazes
Theory of ideal classic gaz
Das Pauliverbot
p . #$%
© Falguni Salkar
S.N. Bose and other Bosons
Bose-Einstein condensate
T<Tc
T>Tc
vs.
cf. le laser atomique
29
30
31
How to determine the
temperature?
2
(t )
v
2
0
2k B T
m
v 2t 2
t=200 s t=500 s t=1000 s
t=2100 s
x 10-3
1.88
MOT laser
data
fit
1.86
1.84
Magnetic field
t
Sigma X (m)
1.82
1.8
1.78
1.76
Image beam
1.74
1.72
1.7
1.68
200
400
600
800
1000
delay (us)
1200
1400
1600
1800
Rotating condensate and vortices
MIT, Cambridge MA, USA
ENS, Paris, France
JILA, Boulder CO
Fermions
34
formation
of pairs
spin-up spin-down
T < Tc
spin-up spin-down
Pairs condensate
35
Further quest to absolute zero ?
What are the applications of the
cold gazes and BEC ?
36