Bose-Einstein Condensation in Microgravity

Bose-Einstein Condensation in Microgravity

S. T. Seidel, Institute of Quantum Optics, Leibniz University of Hanover

S. T. Seidel Bose-Einstein Condensation in Microgravity Varenna, 30.06.2009

Motivation: Microgravity

2Takacc ××=Drr

j

22 TAmAtomrot µW×=D

rr

hj

Sagnac Interferometer

a

W Sensitivity:

§ Extended time of evolution

T


Motivation: BEC

§ Slower free expansion compared to ultra-cold thermal atoms§ Coherent source

BECBEC

Slowing the free expansion by lowering thetrap depth before release of the condensate

Less interaction and potential energyconverted into kinetic energy


The drop tower Bremen

Platform µg-Quality [g] µg-Duration

ISS 10-4 days to months

Space carrier 10-6 3 days

Parabola flights 10-2 20 seconds

Ballistic rockets 10-5 6 minutes

Drop tower 10-6 4.8 s, x 2 with catapult


The drop tower Bremen

§ Free fall: 4.8 s

§ Residual acceleration:

10-5 m/s2 below 100 Hz

§ 3 flights per day

§ Capsule decelerationup to 500 m/s2

§ Strict requirements:

§ Dimensions < 0.6 Æ

x 1.73 m

§ Payload < 234 kg


The QUANTUS Experiment

286 cm

20 cm


Principles of an atom chip: Chip MOT


Experimental Sequence loading phase: 1.1 x 107 atoms in the MOT

temperature: 230 µKloading time: 4,2 s

chip-MOT: 6.5 x 107 atomstemperature: 230 µK

positioning of the trap in 20 ms

molassis phase: cooling down to 15 µK

5.0 x 106 atomsdetuning (29,0 ± 0,4) MHz


loading phase: 1.1 x 107 atoms in the MOT

temperature: 230 µKloading time: 4,2 s

chip-MOT: 6.5 x 106 atoms temperature: 230 µK

positioning of the trap in 20 ms

molasses phase: cooling down to 15 µK

5.0 x 106 atomsdetuning (29,0 ± 0,4) MHz

magnetic trap: 4,5 x 106 atomstemperature: 25 µK

Experimental Sequence


Bose-Einstein Condensate in Microgravity

50 ms

500 ms

1000 ms

1400 µm

§ Over 180 drops

§ Studied the evolution of theoutcoupled condensate forup to 1 second


Next Steps: Bragg atom interferometry

0 1 2

|g>Ener

gy

|e>

)( dw +hdh

wh

Dh

khMomentum in

time

)( dw +hwh

§ Currently in ground test phase


QUANTUS2

§ Adding a second atomic species (potassium)à Demonstrate first Degenerate Fermi Gases in µgà Demonstrate first Bose-Fermi-Mixtures in µgà Test of the weak equivalence principle

§ Increasing the atom number in the BEC to ~105

àbetter signal to noise ratio after longer TOF

§ Capability for high precision atom interferometry

§ Use of the catapult mode of the drop tower in Bremen


The new apparatus QUANTUS2: Overview - Capsules

QU

ANTU

S (d

rop

mod

e)

QU

ANTU

S2 (c

atap

ult

mod

e)

Payload area:ø600x1730 mm à ø600x950 mm

Payload mass:234 kgà163,8 kg

2860

mm

2094

mm

Reduction of size and mass:


The new apparatus QUANTUS2: Vacuum systemCapsule with/without magnetic shields

Vacuum pumpsand electronics

Vacuum chamberMagnetic shield

Laser systems

Used by ZARM


The new apparatus QUANTUS2: Vacuum systemDouble MOT System:

CCD camera head

telescopes

Experiment chamber 2D-MOT

coils

CF16 valve

~420mm


Micro optical bankAlN 13x4x1mm3

Master-OscillatorDFB-RW-LaserPower Amplifier

Trapered- amplifier

Micro lensGRIN-rod lens

The new apparatus QUANTUS2: Laser systemDevelopment of new technologies:

• e.g. Hybrid MOPA system:

• DFB/DBR laser for 767nm• narrow linewidth DFB/DBR laser diodes• ECDL laser on a micro bank

Housing(2.5x2.5x1mm)

At the HU Berlin/Ferdinant-Braun Institutfür Hochfrequenztechnik (FBH)


TEXUS

§ Ballistic missile launch§ Quality of microgravity 10-5 (ZARM 10-6)§ 6 minutes of microgravity (ZARM 9s)


Thank you for your attention

QUANTUS is a collaboration of

Financed by:

Bose-Einstein Condensation in Microgravity

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