World of ultracold atoms with strong interaction - PowerPoint PPT Presentation

About This Presentation
Title:

World of ultracold atoms with strong interaction

Description:

World of ultracold atoms with strong interaction. National Tsing-Hua University. Daw-Wei Wang ... crystalization and no fermionic excitation. How to make ... – PowerPoint PPT presentation

Number of Views:61
Avg rating:3.0/5.0
Slides: 30
Provided by: visi210
Category:

less

Transcript and Presenter's Notes

Title: World of ultracold atoms with strong interaction


1
World of ultracold atoms with strong interaction
Daw-Wei Wang
National Tsing-Hua University
2
Temperature ?
What we mean by ultracold ?
3
Why low temperature ?
Ans To see the quantum effects !
Uncertainty principle
4
(after Nature, 416, 225 (02))
5
Why strong interaction ?
P. Anderson Many is not more
Because interaction can make
many to be different !
Example 1D interacting electrons ?
crystalization and no fermionic excitation
6
How to make interaction stronger ?
7
How to reach ultracold temperature ?
1. Laser cooling ! (1997 Nobel Price)
Use red detune laser Doppler effect
8
How to reach ultracold temperature ?
2. Evaporative cooling !
Reduce potential barrial thermal equilibrium
9
Typical experimental environment
MIT
10
How to do measurement ?
Trapping and cooling
Perturbing
Releasing and measuring
BEC
(2001 Nobel Price)
11
What is Bose-Einstein condensation ?
When T is small enough, noninteracting
bosons like to stay in the lowest energy state,
i.e. BEC
12
How about fermions in T0 ?
D(E)
Fermi sea
E
When T-gt 0, noninteracting fermions form a
compact distribution in energy level.
13
BEC and Superfluidity of bosons
(after Science, 293, 843 (01))
condensate
BEC superfluidity
v
repulsion
Superfluid
uncondensate
Normal fluid
Landaus two-fluid model
14
Phonons and interference in BEC
Interference
Phonondensity fluctuation
(after Science 275, 637 (97))
Matter waves ?
15
Vortices in condensate
Vortex topological disorder
E
L
1
3
2
0
(after Science 292, 476 (01))
Vortices melting, quantum Hall regime ?
(after PRL 87, 190401 (01))
16
Spinor condensation in optical trap
Na
E
F2
F1
B
(see for example, cond-mat/0005001)
17
Boson-fermion mixtures
Fermions are noninteracting !
phonon
fermion
phonon-mediated interaction
Sympathetic cooling
18
Feshbach Resonance
(i) Typical scattering
a
(ii) Resonant scattering
B
Molecule state
19
Molecule and pair condensate
(MIT group, PRL 92, 120403 (04))
(JILA, after Nature 424, 47 (03))
(Innsbruck, after Science 305, 1128 (04))
20
First evidence of superfluidity of fermion pairing
a
B
21
Optical lattice
3D lattice
1D lattice
Entanglement control
22
Mott-Insulator transition
Bose-Hubbard model
n3
superfluid
n2
n1
(after Nature 415, 39 (02))
23
Fermions in optical lattice
Fermi Hubbard model
Superfluidity of fermion pairing in lattice is
also realized.
24
Transport in 1D waveguide
wave guide
Interference ?
Finite temperature semiconductor technique
25
Dipoles in nature
(a) Direct molecules p 1-5 D (b) But
difficult to be cooled
But it is now ready to go !
(Stuhler etc.)
(Doyle, Meijer, DeMille etc.)
26
Condensate (superfluid)
Tc700 nK
27
Cold dipolar atoms/molecules
(a) Direct molecules p 1-5 D (b) But
difficult to be cooled
But it is now ready to go !
(Stuhler etc.)
(Doyle, Meijer, DeMille etc.)
28
Condensate (superfluid)
Tc700 nK
29
Interdisciplinary field
Traditional AMO
Precise measurement
Cosmology
Ultracold atoms
Quantum Information
Nonlinear Physics
Soft-matter/ chemistry
Condensed matter
Write a Comment
User Comments (0)
About PowerShow.com