Precision measurement with ultracold atoms & moleculesjila US_Japan_Seminar.pdf · Precision...

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Precision measurement with ultracold atoms & molecules Jun Ye JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado at Boulder $ Funding $ NIST, ONR, NSF, AFOSR, NASA, DOE http://jilawww.colorado.edu/YeLabs US – Japan Seminar, Breckenridge, August 23, 2006
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  • Precision measurement withultracold atoms & molecules

    Jun Ye

    JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado at Boulder

    $ Funding $

    NIST, ONR, NSF, AFOSR, NASA, DOE

    http://jilawww.colorado.edu/YeLabsUS Japan Seminar, Breckenridge, August 23, 2006

  • Ultracold molecules: Test fundamental principles

    QEDElectronic ~

    e- e-

    e- e-

    Ultrahigh resolution spectroscopy Standards in wide spectral ranges Molecular interferometry Precision measurement

    Excited electronic state

    Ground electronic state

    One system, two different fundamental forces!

    Vibration ~ me/mp(mass on a spring) Strong interactions

  • First, let there be light

    Continuous wave laser: < 1 Hz stability and accuracy

    Ultrafast pulse: < 1 fs generation and control

    Figure of merit: 10-15

    Phase coherence after 1015 optical cycles

    Precision spectroscopy and quantum control at highest resolution over widest optical bandwidth

  • Frequency comb: state-of-the-art

    n= n fr fo

    Optical Synthesizer

    I()

    fr

    f0

    Visible

    Frequency (Hz)1010 1011 1012 1013 1014 1015

    Freq. comb106 :1 Reduction Gear

    Molecular spectroscopyThorpe et al., Science 311, 1595 (2006). C. Gohle et al.,

    Nature 436, 234 (2005).

    Jones et al. PRL 94, 193201 (2005).

    XUV combStowe et al., PRL 96, 153001(2006).

    Quantum control

  • Optical coherence > 1 s, across entire visible

    Laser 21064 nm

    Cavity 2Laser 1700 nm

    Cavity 1

    Laser 1Laser 2

    Femto comb30 m

    noise-cancelled fiber

    35 m

    noise

    -canc

    elled

    fibe

    r

    Ludlow et al., PRL 96, 033003(2006).

    -6 -4 -2 0 2 4 6 8 10

    0

    1

    2

    3

    Lin

    ear

    Sign

    al (a

    . u.) Optical

    linewidth:250 mHz

    4/11/ 2006

    Hz

  • Clean separation between internal & external degrees of freedom

    Control of matter

    Long - term quantum coherence:

    Both in well defined quantum states

  • Magic wavelength dipole trapTrapping of Single Atoms in Cavity QED

    Ye, Vernooy & Kimble, Phys. Rev. Lett. 83, 4987 (1999).

    For clocks: Katori et al., Katori et al., J. Phys. Soc. Jpn 68, 2429 (1999)

    6th Symp. Freq. Standards & Metrology (2002); Phys. Rev. Lett. 91, 173005 (2003).

  • T ~ 0.5 photon recoil~ 220 nK

    Cool Alkaline Earth Strontium

    1S0

    3P1

    1P1

    689 nm(7.4 kHz)

    461nm (32 MHz) 3P0

    698 nm 1 mHz

    ~ 1 mHz ~10-1887Sr 1S0-3P0

    /0 at 1s

    111

    0

    NSQ

    noise

    0Q

    JILA work: Phys.Rev.Lett. 90, 193002 (2003); Phys.Rev.Lett. 93, 073003 (2004); Phys.Rev.Lett. 94, 153001 (2005); Phys.Rev.Lett. 94, 173002 (2005); Phys.Rev.Lett. 96, 033003 (2006); Phys.Rev.Lett. 96, 203201 (2006).

  • Spectroscopy at the magic wavelength

    traph

    1S0

    3P0

    trapclock

    traprecoil

  • Zoom into the carrier of 87Sr 1S0 3P0

    -300 -200 -100 0 100 200 300

    0.65

    0.70

    0.75

    0.80

    0.85

    0.90

    0.95

    1.00

    1.05G

    roun

    d St

    ate

    Popu

    latio

    n (a

    rb.)

    Clock Laser Detuning (Hz)

    Radial Sidebands

    r ~ 125 Hz

    E

    g

  • -20 -10 0 10 20 301200

    1400

    1600

    1800

    2000

    2200

    2400

    2600

    2800

    3000

    3200

    Phot

    on C

    ount

    s

    Clock Laser Detuning (Hz)

    FWHM:4.6 Hz

    April, 2006

    Q ~ 1 x 1014 Single trace without averaging

    Zoom into the carrier of 87Sr 1S0 3P0

    E

    g

    Reproducibility ~ 1 x 10-15

    (March June, 2006)

    Projected stability< 1 x 10-15 at 1 s

  • 3P0 g-factor different than 1S0 due to HFI Shift of ~110 x mF Hz/Gauss for mF=0 State preparation, field control HF structure introduces slight lattice polarization sensitivity

    Differential g-factor Tensor polarizability

    1S0

    3P0

    HFI

    1P1

    3P1

    I = 9/2

    mf

    -9/2

    +9/2

    1S0

    3P0

    mf

    -9/2

    +9/2

    1S0

    3P0

    Santra et al., Phys. Rev. Lett. 94, 173002 (2005).Hong et al., Phys. Rev. Lett. 94, 050801 (2005).Barber et al., Phys. Rev. Lett. 96, 083002 (2006).

  • -400 -200 0 200 4000.00

    0.02

    0.04

    0.06

    0.08

    0.10

    -9/2-7/2

    -5/2

    -3/2

    -1/2+1/2

    +3/2

    +9/2+7/2

    3 P0 S

    igna

    l (N

    orm

    .)

    Laser Detuning (Hz)

    +5/2

    Optical Measurement of Nuclear g-factor (NMR-like experiment in the optical domain)

    21+

    29+

    23+

    25+

    27+

    21+

    29+

    23+

    25+

    27+

    21

    272

    92

    52

    3

    21

    272

    9

    25

    23

    01S

    03P

    No net electronic angular momentumg = -108.5(4) Hz/(G mF)3P0 lifetime 140(40) s

    1S0

    3P0

  • 0 1 2 3 4 5 60

    2

    4

    6

    8

    Occ

    urre

    nces

    Transition Linewidth (Hz)

    Fourier Limit ~1.8 Hz

    -6 -4 -2 0 2 4 6

    0.00

    0.02

    0.04

    0.06

    0.08

    0.10

    3 P0(m

    F=5/

    2) P

    opul

    atio

    n

    Laser Detuning (Hz)

    1.5 Hz

    -6 -4 -2 0 2 4 6

    0.00

    0.02

    0.04

    0.06

    0.08

    0.10

    3 P0(m

    F=5/

    2) P

    opul

    atio

    n

    Laser Detuning (Hz)

    2.1 Hz

    Coherent spectroscopy Q ~ 3 x 1014

    -60 -30 0 30 60 90 1200.00

    0.04

    0.08

    0.12

    0.16

    0.20

    3 P0(m

    F=5/

    2) P

    opul

    atio

    n

    Laser Detuning (Hz)

    -10 -5 0 5 100.00

    0.04

    0.08

    10 Hz

    1.7 Hz

    Ramsey

  • Ultracold Sr2 molecules via narrow-linePhotoassociation

    3P1 + 1S0

    1S0 + 1S0

    Laser detuning

    Trap Loss

    < 100 kHz

    Zelevinsky et al., Phys. Rev. Lett. 96, 203201 (2006).

  • Narrow-line Photo-association Spectroscopy

    New Territory for PAS

    Interesting regime, C3 C6 crossover

    Ground/Excited state similar for large detunings

    Hyperfine-free for bosonic isotopes Useful for precision tests Optical control of cold collisions with

    low loss

    66

    33

    RC

    RC

    at ~500 MHz

    (5s2) 1S0

    689 n

    m,

    = 7.

    6 kH

    z

    3P1 (5s5p)All bound states are resolved by the narrow line

    Theory: Paul Julienne

  • -polarizedprobe

    magicStarkshift

    1S0

    3P1

    mJ0 +1-1

    0.5 Wstanding wave

    lattice>>recoil

    PAlaser

    Doppler- and recoil-free

    Photoassociation inside a Magic wavelength lattice

    3P0

    1S0

    700 750 800 850 900Laserwavelength nm

    -450-400-350-300-250-200

    Star

    k sh

    ift (k

    Hz)

    1S0

    3P0

    3P1

  • Photoassociation: Experiment vs. theory

    Nine least bound states measured

    10-5 agreement for near detuning, 0.1-1% agreement deeper in the potential curve

  • Ground State Molecules

    Vg

    0uSimilar excited and ground state wavefunctions~90% of molecules in 8.4 GHz state decay to single g.s.

    Should be possible to drive Molecules to deepest g.s.

    Sr2

    Magic wavelength trap for molecules?Theory: P. Julienne and A. Derevianko

    pump probe

    (pump probe) < 0.5 Hz

    Time-variation of electron-proton mass ratio?D. DeMille, private communications (2005). Chin and Flambaum, Phys. Rev. Lett. 96, 230801 (2006).

  • Test of fundamental constants

    Early universe Not so clearWebb et al., PRL 87, 091301 (2001).Astron. Astrophys. 415, L7 (2004). Conflicting results

    Impact

    : fine structure constantModern epoch

    Atomic clock measurementsare consistent with zero

    / < 10-15/yr

  • Cold OH molecules to constrain

    Hyperfineinteractions ~ 4

    Lambda doubling ~ 0.423/2

    F= 2

    F= 1

    F= 2

    F= 1Multiple transitions from the same gas cloud (different dependences on )(Self check on systematics)Current uncertainly in laboratory based experiments is 100 Hz,leading to / ~ 10-5

    ter Meulen & Dymanus, Astrophys. J. 172, L21(1972).

    OH megamasers

    High redshift z > 1Darling, Phys. Rev. Lett 91, 011301 (2003).Chengalur et al., Phys. Rev. Lett. 91, 241302 (2003).Kanekar et al., Phys. Rev. Lett. 93, 051302 (2004).

  • Stark Decelerator

    Slower electrodes

    Star

    k en

    ergy

    Position

    G. Meijer

  • OH after the Stark-decelerator

    1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.80.00

    0.25

    0.50

    0.75

    1.00

    OH

    den

    sity

    (arb

    .)

    Time (ms)

    370 m/s

    336 m/s

    300 m/s

    259 m/s211 m/s

    148 m/s 33 m/s

    Bochinski et al., Phys. Rev. Lett. 91, 243001 (2003); PRA 70, 043410 (2004).

    Beam: 550 m/s to restTemp: 1 K to 10 mK104 106 molecules105 107 /cm3 density

  • Cold molecule based precision spectroscopy

    PMT

    Excitation laserMicrowave Interrogation cavity

    HexapoleDecelerator

    Rabi or Ramsey interrogation on slowed OH beam High resolution and precision Systematic checks on beam (velocity) effects

    Detection can

  • Weightedstandard meanerror range

    Hudson et al., Phys. Rev. Lett. 96, 143004 (2006).

    Precision measurement of OH structure

  • / measurement status

    / = 1 ppm (and better) is now possible to measure over ~10 Gyr.Linear drift model 10-16/yr.

    Astrophysical measurements later this year plan better than 100 Hz accuracy.

    Deep surveys of OH megamasers are active from the local Universe to red shift z ~ 4.

    Optical clock comparisons ongoing, but test only modern epoch.

    Tests on (me/mp) / (me/mp) is possible (W. Ubach, PRL 92, 101302 (2004); PRL 96, 151101 (2006).)

    e- e-

    e- e-

  • Special thanks

    Femtosecond comb& cold atoms

    S. ForemanM. ThorpeD. HudsonM. StoweDr. A. PeerDr. R. J. Jones (Arizona)Dr. K. Moll (Precision Ph)

    Ultracold Sr & Sr2

    M. BoydA. LudlowS. BlattDr. T. ZelevinskyDr. T. ZanonDr. T. Ido (NICT,Tokyo)

    Cold Polar Molecules

    B. SawyerB. StuhlDr. B. LevE. Hudson (Yale)

    http://jilawww.colorado.edu/YeLabs

    Collaborators

    J. Bohn, S. Cundiff, C. Greene, J. Hall (JILA) P. Julienne, S. Diddams, J. Bergquist, L. Hollberg, T. Parker (NIST)

    E. Eyler (UConn), F. Krausz (MPQ)

  • |e,n>

    |g,n+1>

    |e,n-1>

    |g,n>

    Dipole force fluctuations: Heating and position-dependent decoherence

    FORT beam

    CQED probe

    Caltech cavity QED lessonKimble group, 1999

    The Solution:Match the AC Stark shift

    between |e> and |g>

    |e,n>

    |g,n+1>

    |e,n-1>

    |g,n>

    Kimble et al. ICOLS 99

    Problems in the neutral atom land

  • Reproducibility

    -20 0 20 40 60 80 1001201401600

    20

    40

    60

    80

    100

    120

    Sam

    ples

    Optical frequency deviations (Hz)

    40 60 80 100 1200

    10

    20

    30

    40

    50

    60

    Sam

    ples

    Optical frequency deviations (Hz)

    0 200 400 600 800 100066

    68

    70

    72

    74

    76

    Opt

    ical

    line

    cent

    er fr

    eque

    ncy

    (Hz)

    Error tolerance (Hz)

    0 = 429,228,004,229,800 Hz

    Center: 71.4 Hz 0.4 Hz

    March June 2006: 1020 measurements3 different NIST Cs-calibrated masers

    1020 samples

    1000 samples

    2 Hz optical

    Statistical error < 1 x 10-15

  • Global Sr Clock Comparison

    800

    820

    840

    860

    880

    900

    920

    940

    960

    JILA 2006(Preliminary)

    Measurements Fre

    quen

    cy- 4

    29,2

    28,0

    04,2

    29,0

    00 H

    z

    Tokyo 2005

    JILA 2005

    Paris 2006

    Tokyo 2006? PTB?

    Takamoto et al., Nature 435, 321 (2005). Ludlow et al., Phys. Rev. Lett. 96, 033003

    ~10 months

    ?

  • 1 MHz error in lattice wavelength 5 x 10-18 clock inaccuracy

    How Magic is the wavelength?

    813.2 813.4 813.6 813.8

    -400

    -300

    -200

    -100

    0

    100

    200

    300 R

    elat

    ive

    Clo

    ck F

    requ

    ency

    (Hz)

    Lattice Wavelength (nm)

    Sensitivity 884(15) Hz/nmI0= 10 kW/cm2

    Ludlow et al., Phys. Rev. Lett. 96, 033003 Brusch et al., Phys. Rev. Lett. 96, 103003 (2006).

  • -40 -30 -20 -10 0 10 20 30 40

    10

    20

    30

    40

    50

    60

    70

    80

    1 S0-3

    P 0 L

    inew

    idth

    (Hz)

    Magnetic Field (mG)

    Total uncertainty ~0.5 Hz 1 x 10-15

    -0.2 -0.1 0.0 0.1 0.2-120-100

    -80-60-40-20

    020406080

    100120

    Freq

    uenc

    y (H

    z)

    Magnetic Field (G)

    -47.5 (32) Hz/ GField Uncertainty 13mGSystematic uncertainty = 0.42 Hz

    Magnetic Shift: -47 (32 Hz)/G

    Understanding systematics:Magnetic sensitivities

    Magnetic Broadening

  • Trapped ion optical frequency standards

    Ultra-stable probe laser

    (local oscillator)

    Single coldtrapped ion

    (atomic reference)

    Femtosecond comb (counter)

    Optical clocks future redefinition of the second?Fundamental constants and tests of physics

    Future satellite navigation and ranging?

    199Hg+, 88Sr+, 171Yb+,40Ca+, 115In+, 27Al+

    NIST Hg+ systematic uncertainty< atomic fountain clock(Bergquist et al., 2006)

    Helen MargolisPatrick Gill, et al., NPL

  • The point:Long coherence time in quantum measurement

    Quantum Information science:NIST, Innsbruck, Michigan, Oxford, MIT, Ulm,

    Precision Measurement/Standards: NIST, NPL, PTB, NRC, JPL, Innsbruck, Harvard, MPQ, Dusseldorf,

    Ion traps: Clean separation between the internal and external degrees of freedom

  • Wim Ubachs

    Precision spectroscopy of H2and a possible variation of mp/me

    over cosmological time

    Dimensionless constants of nature:

    1/ = 137.035 999 11 (46)

    = Mp/me = 1836.152 672 61 (85)

    various g - factors

    Fundamental constants ?

    Just empirical or deeper theory ?

    Molecular structure and possibility of lif

    Constant or slightly varying ?

    PRL 96, 151101 (2006).

  • Matching the polarizabilities

    3P0

    1S0

    700 750 800 850 900Laser wavelength nm

    - 450

    - 400

    - 350

    - 300

    - 250

    - 200St

    ark

    shift

    (kH

    z)

    1S0

    3P0

    1S0

    3P0 Sr, Yb, Ca, Hg,

  • -800 -600 -400 -200 0 200 400 600 8000.00

    0.02

    0.04

    0.06

    3 P0 S

    igna

    l (N

    orm

    .)

    Laser Detuning (Hz)

    -7/2+9/2+7/2 -9/2

    Optical Measurement of Nuclear g-factor

    +-

    21+

    29+

    23+

    25+

    27+

    21+

    29+

    23+

    25+

    27+

    21

    272

    92

    52

    3

    21

    272

    9

    25

    23

    01S

    03P

    No net electronic angular momentumg = -108.5(4) Hz/(G mF)3P0 lifetime 140(40) s

    1S0

    3P0

  • Ultracold Sr2 molecules to test time-variation of electron-proton mass ratio

    PumpProbe

    Sr2

    pump probe

    (pump probe) < 0.5 Hz

    Chin and Flambaum, Phys. Rev. Lett. 96, 230801 (2006).D. DeMille, private communications (2005).

    Magic wavelength trap for molecules?Theory: P. Julienne and A. Derevianko

  • Oscillator

    Counter

    a

    Atoms

    New era for optical atomic clocks

    NIST, JILA, PTB, NPL, SYRTE,

    Feedback(accuracy)

    Ultrastable laser

    optical comb

    optical frequencysynthesizer & counter

    RF or opticalreadout

  • Possible systematics in space

    Electro-Magnetic field in space

    Different velocities for different lines

    Solutions:

    OH sum rule

    Main lines versus satellite lines

    Emission and conjugate absorption

  • The OH ground state in a B-Field

    -2 -1 0 1 2

    SUM (2 satellites) = SUM (2 main lines)

    Satellites calibrate B

    Observed satellites conjugate

    Kanekar et al., Phys. Rev. Lett. 93, 051302 (2004).

    Ultracold molecules: Test fundamental principlesFrequency comb: state-of-the-artClean separation between internal & external degrees of freedomSpectroscopy at the magic wavelengthOptical Measurement of Nuclear g-factor Test of fundamental constantsCold OH molecules to constrain a OH after the Stark-deceleratorCold molecule based precision spectroscopyReproducibilityGlobal Sr Clock ComparisonTrapped ion optical frequency standardsThe point:Long coherence time in quantum measurementOptical Measurement of Nuclear g-factor Ultracold Sr2 molecules to test time-variation of electron-proton mass ratioPossible systematics in space