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ABSTRACT: We describe a method for determining the radiative decay properties of a molecule by studying the saturation of laser-induced fluorescence and the associated power broadening of spectral lines. The fluorescence saturates because the molecules decay to states that are not resonant with the laser. The amplitudes and widths of two hyperfine components of a spectral line are measured over a range of laser intensities and the results compared to a model of the laser-molecule interaction. Using this method we measure the lifetime of the A(v'=0) state of CaF to be tau=19.2 \pm 0.7 ns, and the Franck-Condon factor for the transition to the X(v=0) state to be Z=0.987 (+0.013 || -0.019). In addition, our analysis provides a measure of the hyperfine interval in the lowest-lying state of A(v'=0), Delta_e=4.8 \pm 1.1 MHz.
10/2008;
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ABSTRACT: We report progress towards making a precise measurement of the 2S Lamb shift in singly-ionised helium by spectroscopy of the
2S-3S transition. The motivation for the experiment is discussed with reference to recent developments in the theory of quantum
electrodynamics (QED) and a description of the apparatus and techniques used is given.
12/2007: pages 303-313;
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ABSTRACT: We present a general discussion of the techniques of destabilizing dark states in laser-driven atoms with either a magnetic field or modulated laser polarization. We show that the photon scattering rate is maximized at a particular evolution rate of the dark state. We also find that the atomic resonance curve is significantly broadened when the evolution rate is far from this optimum value. These results are illustrated with detailed examples of destabilizing dark states in some commonly-trapped ions and supported by insights derived from numerical calculations and simple theoretical models. Comment: 14 pages, 10 figures
11/2001;
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ABSTRACT: Magnetic videotape is of great interest for trapping and guiding cold atomic vapors, but was hitherto considered unsuitable
for manipulating Bose–Einstein condensates (BEC) because of the presumed evolution of gas under vacuum. We have studied the
outgassing in vacuum of the most promising tape, Ampex 398 Betacam SP. We find that after cleaning in ethanol and baking for
200h at 100°C the magnetic patterns are undisturbed and the outgassing is remarkably small: 4×10-10Torr l s-1cm-2, due mostly to hydrogen. This makes the tape exceedingly attractive for manipulation of BEC.
Applied Physics B 06/2001; 73(1):51-54. · 2.19 Impact Factor
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ABSTRACT: A versatile miniature de Broglie waveguide is formed by two parallel current-carrying wires in the presence of a uniform bias field. We derive a variety of analytical expressions to describe the guide and present a quantum theory to show that it offers a remarkable range of possibilities for atom manipulation on the submicron scale. These include controlled and coherent splitting of the wave function as well as cooling, trapping, and guiding. In particular, we discuss a novel microscopic atom interferometer with the potential to be exceedingly sensitive.
Physical Review Letters 03/2001; 86(8):1462-5. · 7.37 Impact Factor
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V. Meyer,
S.N. Bagayev,
P.E.G. Baird,
P. Bakule, M.G. Boshier,
A. Breitrück,
S.L. Cornish,
S. Dychkov,
G.H. Eaton,
A. Grossmann, [......],
I. Reinhard,
P.G.H. Sandars,
R. Santra,
P. Schmidt,
C.A. Scott,
W.T. Toner,
M. Towrie,
K. Träger,
L. Willmann,
V. Yakhontov
[show abstract]
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ABSTRACT: The 1s–2s energy interval in the muonium (μ+e−) atom has been measured by Doppler free two photon laser spectroscopy. A value of 2455528941.0(9.8) MHz has been obtained
in good agreement with quantum electrodynamics (QED). The muon-electron mass ratio can be extracted and is found to be 206.76838(17).
The measurement may also be interpreted as a determination of the muon-electron charge ratio as -1- 1.1(2.1)· 10−9. Corresponding measurements in deuterium using the same experimental setup confirmed the validity of the applied analysis
procedure.
Hyperfine Interactions 07/2000; 127(1):197-200. · 0.21 Impact Factor
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P. Bakule,
P.E.G. Baird, M.G. Boshier,
S.L. Cornish,
D.F. Heller,
K. Jungmann,
I.C. Lane,
V. Meyer,
P.H.G. Sandars,
W.T. Toner,
M. Towrie,
J.C. Walling
[show abstract]
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ABSTRACT: A Q-switched alexandrite laser suitable for high-resolution spectroscopy is described which produces pulses of 35 mJ energy in a 10 MHz bandwidth, with a high-purity TEM00 mode. The laser can be synchronised to external event to within 100 ns. The output pulse length is 120 ns and the repetition rate 25 Hz. The laser is injection-seeded by a Ti:sapphire laser operating around 730 nm. To preserve single-mode seeding under external triggering conditions, and to obtain small time-jitter, active cavity length control was used. In order to achieve the 10 MHz output bandwidth, intra-cavity electro-optic modulators were used to compensate for the frequency chirp. The refractive index of alexandrite was found to vary linearly with inversion density with a constant of proportionality equal to 1.6᎒-24 cm3. In pulsed operation at 730 nm, the index change due to this effect is only partially compensated by changes due to ground state phonon relaxation.
Applied Physics B 06/2000; 71(1):11-17. · 2.19 Impact Factor
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ABSTRACT: . Low energy pulsed muon beams at the front end of a muon collider may provide some 5 orders of magnitude greater intensity than present sources. This suggests dramatic possibilities for high precision spectroscopic and other measurements on muonic atoms, which could importantly extend our tests of QED, measurements of fundamental constants, and tests of physics beyond the standard model. INTRODUCTION Much of the early development and testing of quantum electrodynamics was founded on measurements of energy levels in electronic atoms, as was our knowledge of many fundamental constants. In the recent past, the precision of these measurements has reached astounding levels; for example, the ground state hyperfine interval in hydrogen, Delta (H), is known to better than a part in 10 12 [1]. Our enthusiasm is tempered when we note that the theoretical prediction for Delta (H) is six orders of magnitude less precise (at the 1 ppm level), due to the difficulties in calculating strong inte...
06/1999;
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ABSTRACT: By means of saturated absorption spectroscopy in a discharge tube containing hydrogen isotopes, fine-structure intervals in the Balmer- alpha line of tritium have been measured, and for each of four components of that line the tritium-hydrogen and tritium-deuterium isotope shifts have been measured. The results agree with theory within the experimental limits of error, which are typically +or-2 MHz. The profiles of the components of Balmer- alpha have been analysed in detail and in particular a Stark-induced crossover signal has been revealed.
Journal of Physics B Atomic Molecular and Optical Physics 12/1998; 21(3):421. · 1.88 Impact Factor
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ABSTRACT: We have demonstrated that a suitably magnetized surface can be used to retroreflect cold atoms for applications in atom optics. This has some advantages relative to evanescent wave mirrors because no light is involved. Multiple bounces of cold rubidium atoms have been observed for times up to 1 s in a trap formed by gravity and a 2 cm diameter spherical mirror made from a flexible computer disk (`floppy disk'). We have studied the dynamics of the atoms bouncing in this trap from several different heights up to 40.5 mm and we conclude that the atoms are reflected specularly and with reflectivity 1.01(3). The performance of this mirror is limited at present by collisions with the background gas and by unwanted harmonics in the magnetization of the surface. This is the first in a series of papers concerning the use of magnetized surfaces in atom optics.
Journal of Physics B Atomic Molecular and Optical Physics 12/1998; 30(3):647. · 1.88 Impact Factor
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M.G. Boshier,
S. Dhawan,
O. van Dyck,
P. Egan,
X. Fei,
M.G. Perdekamp,
V.W. Hughes,
M. Janousch,
K. Jungmann,
D. Kawall,
W. Liu,
F.G. Mariam,
C. Pillai,
R. Prigl,
G.zu. Putlitz,
I. Reinhard,
W. Schwarz,
P.A. Thompson,
K.A. Woodle
[show abstract]
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ABSTRACT: Data-taking has been completed on a new high precision experiment
at the Los Alamos Meson Physics Facility (LAMPF) to determine the
muonium (μ<sup>+</sup>e<sup>-</sup>) ground state hyperfine structure
interval Δν (to ~10 ppb) and the muon to proton magnetic moment
ratio μ<sub>μ</sub>/μ<sub>p</sub> (to ~90 ppb), each
corresponding to about a fourfold improvement compared to present
knowledge
Precision Electromagnetic Measurements Digest, 1998 Conference on; 08/1998
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V. Meyer,
S.N. Bagayev,
P.E.G. Baird,
P. Bakule, M.G. Boshier,
A. Breitruck,
S.L. Cornish,
S. Dychkov,
G.H. Eaton,
A. Grossmann, [......],
P.G.H. Sandars,
R. Santra,
P. Schmidt,
C.A. Scott,
W.T. Toner,
M. Towrie,
K. Trager,
C. Wasser,
L. Willmann,
V. Yakhontov
[show abstract]
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ABSTRACT: A new measurement of the 1S-2S energy splitting of muonium by
Doppler-free two-photon spectroscopy has been performed at the
Rutherford Appleton Laboratory in Chilton, Didcot, UK. Increased
accuracy is expected compared to a previous experiment. Spectroscopy of
this transition promises an improvement of the muon mass value
Precision Electromagnetic Measurements Digest, 1998 Conference on; 08/1998
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ABSTRACT: We have measured the hydrogen 1S Lamb shift to be 8,172,827(51)
kHz, the most precise value for any Lamb shift. The result is in
reasonable agreement with the predictions of quantum electrodynamics
(QED), although its interpretation as a test of QED is limited by the
uncertainty in the proton charge radius. A measurement of the He<sup>+
</sup>(2S) Lamb shift by laser spectroscopy can bypass this limitation
and investigate a nine standard deviation discrepancy between theory and
experiment for this Lamb shift
Precision Electromagnetic Measurements Digest, 1996 Conference on; 07/1996
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ABSTRACT: An experiment is in progress at the Los Alamos Meson Physics Facility (LAMPF) to determine with high precision the hyperfine structure interval Δv (to ~10 ppb) and the muon to proton magnetic moment ratio μ<sub>μ</sub>/μ<sub>p</sub>(to ~60 ppb) in the ground state of muonium (μ<sup>+</sup>e<sup>-</sup>). These precision goals correspond to increases in precision of Δv and of μ<sub>μ</sub>/μ<sub>p</sub> by about a factor of 5 compared to present knowledge
Precision Electromagnetic Measurements Digest, 1996 Conference on; 07/1996
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ABSTRACT: An experiment is in progress at the Los Alamos Meson Physics Facility (LAMPF) to determine with high precision the hyperfine structure interval {Delta}{nu} (to {approximately} 10 ppb) and the muon to proton magnetic moment ratio {mu}{sub {mu}}/{mu}{sub p} (to {approximately} 60 ppb) in the ground state of muonium ({mu}{sup +}e). These goals correspond to increases in precision of {Delta}{nu} and of {mu}{sub {mu}}/{mu}{sub p} by about a factor of 5 compared to present knowledge, which will provide the most precise test of bound-state QED for a two-lepton system and new values for the muon mass and the fine structure constant {alpha}. The experimental method is microwave magnetic resonance spectroscopy and it uses the {open_quotes}old muonium{close_quotes} line-narrowing technique. During runs in 1994 and 1995 with a total beam time of about 3 mos., data were taken with stopping Kr gas pressures of 0.5, 1.0 and 1.5 atm. Some 40,000 resonance lines were obtained. The status of the experiment and of the authors analysis of the data will be reported.
Bulletin of the American Physical Society. 04/1996; 41(3).
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W. Schwarz,
P.E.G. Baird,
J.R.M. Barr,
D. Berkeland, M.G. Boshier,
B. Braun,
G.H. Eaton,
A.I. Ferguson,
H. Geerds,
V.W. Hughes, [......],
G.Z. Putlitz,
I. Reinhard,
E. Riis,
P.G.H. Sanders,
W.T. Toner,
M. Towrie,
L. Willmann,
K.A. Woodle,
K.A. Woodman,
L. Zhang
[show abstract]
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ABSTRACT: A new measurement of the
1<sup>2</sup>S<sub>1/2</sub>-2<sup>2</sup>5<sub>1/2</sub> energy
splitting in muonium (μ<sup>+</sup>e<sup>-</sup>) by Doppler-free
two-photon laser spectroscopy yields a value of 2 455 529 002 (33) (46)
MHz, where the 33 MHz error arises from statistics and the 46 MHz
uncertainty is due to systematic line shifts. The experiment agrees with
quantum electrodynamics theory within two standard deviations. The mass
of the positive muon can be derived as 105.65880 (29) (43) MeV/c<sup>2
</sup> from the measured muonium-hydrogen and muonium-deuterium 1S-2S
isotope shifts. The measurement may alternatively be interpreted as a
test of the equality of the electric charges of muon and electron with a
precision of 1.4 (1.2) l0↑{-8}
IEEE Transactions on Instrumentation and Measurement 05/1995; · 1.21 Impact Factor
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K. Jungmann,
P. E. G. Baird,
J. R. M. Barr,
D. Berkeland, M. G. Boshier,
B. Braun,
G. H. Eaton,
A. I. Ferguson,
H. Geerds,
V. W. Hughes, [......],
I. Reinhard,
E. Riis,
P. G. H. Sandars,
W. Schwarz,
W. T. Toner,
M. Towrie,
L. Willmann,
K. A. Woodle,
G. Woodman,
L. Zhang
[show abstract]
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ABSTRACT: Resonant ionization spectroscopy has been employed for measuring the 12S1/2−22S1/2 frequency difference in the hydrogen‐like muonium atom to 2 455 529 002(33)(46) MHz. The 1S‐2S two‐photon transition was induced Doppler‐free using two counter‐propagating laser beams. The 2S state was photo‐ionized by a third photon from the same laser field. The measurement agrees with QED theory within two standard deviations. The mass of the positive muon can be extracted from the isotope shifts in this transition to hydrogen and deuterium to 105.658 80(29)(43) MeV/c2. © 1995 American Institute of Physics
AIP Conference Proceedings. 03/1995; 329(1):197-202.
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F E Maas,
B Braun,
H Geerds,
K Jungmann,
B E Matthias,
G Putlitz,
I Reinhard,
P E G Baird,
P G H Sandars,
G S Woodman, [......],
W T Toner,
M Towrie,
J R M Barr,
A I Ferguson,
M A Persaud,
E Riis,
D Berkeland, M G Boshier,
V W Hughes,
K A Woodle
Phys. Lett. A. 01/1994; 187:247-254.
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ABSTRACT: We have excited the 1S‐2S transition in atomic hydrogen and deuterium by two‐photon absorption of cw 243 nm light. The transition frequency has been measured by comparison with calibrated lines in the spectrum of the 130Te2 molecule, providing new precise values for the 1S Lamb shifts or the Rydberg constant.
AIP Conference Proceedings. 09/1988; 172(1):319-322.
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ABSTRACT: The hydrogen atom is an important testing ground for fundamental physical theory, because it is the simplest stable atomic system and its properties can be calculated to enormous precision. Measurements on hydrogen played a major role in the development of quantum electrodynamics (QED), a theory of electromagnetic interactions which includes quantization of the radiation field1,2. Tests of QED in hydrogen involve precision measurements of transition frequencies; the transition generally studied is between two excited states (2s
2
S
1/2 and 2p
2
P
1/2). Much higher precision is possible if a transition involving the ground state is studied, but this potential has not so far been exploited because of experimental difficulties. We have now carried out an experiment of this type which has given preliminary results and opens new possibilities for precision tests of QED in the future.
12/1987; 330(6147):463-465.
