QUANTUS Quantengase Unter Schwerelosigkeit (Quantum Gases under - - PowerPoint PPT Presentation

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QUANTUS Quantengase Unter Schwerelosigkeit (Quantum Gases under - - PowerPoint PPT Presentation

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QUANTUS Quantengase Unter Schwerelosigkeit (Quantum Gases under Microgravity) Achim Peters for the QUANTUS team Workshop on Advances in Precision Tests and Experimental Gravitation Galileo Galilei Institute for Theoretical Physics, Arcetri,

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SLIDE 1

Quantengase Unter Schwerelosigkeit (Quantum Gases under Microgravity)

QUANTUS

Achim Peters

for the QUANTUS team

Workshop on Advances in Precision Tests and Experimental Gravitation Galileo Galilei Institute for Theoretical Physics, Arcetri, Firenze, 28th September 2006

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SLIDE 2

The QUANTUS Team

MPI für Quantenoptik Garching / München Universität Hamburg Universität Hannover ZARM & Universität Bremen Universität Ulm

Funding:

Humboldt Universität zu Berlin

DLR 50 WM 0346

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SLIDE 3

BEC in Free Fall: Shifting the Frontiers in Physics

Low est tem peratures/ energies Largest quantum objects Longest tim e of flight for quantum objects

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SLIDE 4

Signal at the output ports

See e.g. : Ch. J. Bordé, Gen. Rel. Grav. 3 6 , (2004), 475

Long Evolution Time High Sensitivity

|e〉 |g〉

time

T 2T

⎩ ⎨ ⎧ ∝ ∝ gradients gravity gravity, for T rotations recoil, frequency, for T ) T (

2

f S

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SLIDE 5

Lowest Energy Scales

103 100 10-3 10-6 10-9 10-12 K 10-13 10-16 10-19 10-22 10-25 GeV 10-20 10-23 10-26 10-29 10-32 10-35 J "classical" phase transitions macroscopic quantum phenomena "quantum" phase transitions

? ?

current record: 450 pK

  • W. Ketterle et al.

10-38 10-28 10-15

QUANTUS

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SLIDE 6

New Length Scales

v d

cl dB

r < λ

individual particles classical gas

dB

λ

d

dB <

λ

individual wave packets precision measurements

d

dB >

λ

macroscopic matter wave macroscopic coherence QUANTUS

? ?

  • coherence limits ?
  • granularity
  • space time fluct. ?
  • ....

sub mm scale mm to cm scale

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SLIDE 7

Free Fall: up to 4.5 sec Duration > 1 BEC-Experiment 3 flights per day Test of a robust BEC Facility Dimensions < 0.6 ∅ x 1.5 m Height 110 m

The ZARM Drop Tower

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SLIDE 8

The ZARM Katapult

Doubling the Free Fall Time to 9 seconds …

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SLIDE 9

Experimental Environment

110 m ~ 4.74 s at µg acceleration 110 m ~ 4.74 s at µg acceleration

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SLIDE 10

A typical BEC laboratory experiment

The Challenge …

Drop capsule Drop capsule boundary conditions Laser Electronics Vacuum Computer h = 1.73 m d = 0.6 m

  • av. Power < 280 W

Weight < 274 kg

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SLIDE 11

Laser System

2 spectroscopy stabilized master laser Beat stabilized MOPA amplifier module Distribution Module (AOM) Two frequency ranges required for 87Rb BEC

E F

3 2 1 2 1 Repumper Cooling, Pumping, Detection 6.8 GHz

52S1/2 52P3/2 4 m odules

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SLIDE 12

Mechanically Stable Optical Components

26 cm

2 cm

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SLIDE 13

Laser Modules

DFDL master module MOPA module FM master module

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SLIDE 14
  • all components are integrated in the system
  • laser modules guarantee a flexible setup
  • robust laser design for drop tower experiments

45 cm

Completed Laser System

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SLIDE 15
  • 20

20 40 60 80

  • 2

2 4

time [ms]

z-acceleration [g]

  • 0,4
  • 0,2

0,0 0,2 0,4

error MTS [V]

  • 0,1

0,0 0,1

error DAVLL [V]

  • 0,4

0,0 0,4

error offset [V]

2000 4000 6000

  • 1000

1000 2000 3000 4000 5000 6000 7000 1 2 3 4 5 6 7 8 9

PDM2HHr [V] time [ms]

frequency stability test during release fiber coupling stability during the flight

Drop Tower Tests of Laser System

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SLIDE 16

drop hight ca. 1,2m

LASER

damping linear ball bearing Magnets design: Katharina Elbs

Laboratory Tests of Laser System

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SLIDE 17

0,0 0,5 1,0 1,5

  • 30
  • 20
  • 10

10 20 30 40 50

z-acceleration [g] time [s]

0,0 0,5 1,0 1,5

  • 0,1

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0

correction [V] error /

Laboratory Tests of Laser System

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SLIDE 18

0,00 0,05 0,10 0,15 0,20 0,25 0,30 10 20 30 40 50 10 20 30 40 50

z-acceleration [g] time [s]

Laboratory Tests of Laser System

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SLIDE 19

0,00 0,05 0,10 0,15 0,20 0,25 0,30 10 20 30 40 50 0,00 0,05 0,10 0,15 0,20 0,25 0,30 10 20 30 40 50 0,00 0,05 0,10 0,15 0,20 0,25 0,30 10 20 30 40 50 10 20 30 40 50

z-acceleration [g] time [s] recapture of the capsule time [s] time [s]

Laboratory Tests of Laser System

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SLIDE 20

0,00 0,05 0,10 0,15 0,20 0,25 0,30 10 20 30 40 50 0,00 0,05 0,10 0,15 0,20 0,25 0,30 10 20 30 40 50 0,00 0,05 0,10 0,15 0,20 0,25 0,30 10 20 30 40 50 10 20 30 40 50

Katapult z-acceleration [g] time [s] Fallturm Aufprall time [s] time [s]

Laboratory Tests of Laser System

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SLIDE 21

Drop Capsule Integration

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SLIDE 22

Modified Iongetterpump (20l/ s) to withstand strong forces (50g at impact) Pressure in the lower 10-10 mbar regime

Experiment Chamber

Single chamber design for size minimization Fully fiber coupled Robust coil arrangement

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SLIDE 23

Mirror MOT

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SLIDE 24

Atom-Chip-MOT

  • 60
  • 6
  • 4
  • 2

2 4 6 0,0 2,0x10

6

4,0x10

6

6,0x10

6

8,0x10

6

1,0x10

7

1,2x10

7

1,4x10

7

  • ptimized

200 µm displacement between MOT and U-MOT

atoms time after loading on the chip [ms]

  • 12·106 atoms loaded into the external MOT,
  • 85% transfer efficiency into chip-MOT,
  • 40mK temperature after molasses-cooling,
  • transfer to magnetic trap,
  • evaporative cooling (in progress)
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SLIDE 25

Outlook: Drop BEC Experiments

Next Steps:

  • Evaporation and realization of lab BEC
  • Transfer to the ZARM drop tower
  • First BEC under microgravity

First experimental questions:

  • Large scale time of flight expansion and interference
  • Adiabatic trap expansion for lowest temperatures
  • Equivalence of free fall and "free" space
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SLIDE 26

The QUANTUS Team