We use Bloch oscillations to transfer coherently many photon momenta to atoms. Then we can measure accurately the recoil velocity \(\hbar k/m\) and deduce the fine structure constant \(\alpha\). The ...velocity variation due to Bloch oscillations is measured using atom interferometry. This method yields to a value of the fine structure constant \(\alpha^{-1}= 137.035 999 45 (62)\) with a relative uncertainty of about \(4.5 \times 10^{-9}\).
Phys.Rev.Lett.101:230801,2008 We report a new experimental scheme which combines atom interferometry with
Bloch oscillations to provide a new measurement of the ratio
$h/m_{\mathrm{Rb}}$. By using ...Bloch oscillations, we impart to the atoms up to
1600 recoil momenta and thus we improve the accuracy on the recoil velocity
measurement. The deduced value of $h/m_{\mathrm{Rb}}$ leads to a new
determination of the fine structure constant $\alpha^{-1}=137.035 999 45 (62)$
with a relative uncertainty of $4.6\times 10^{-9}$. The comparison of this
result with the value deduced from the measurement of the electron anomaly
provides the most stringent test of QED.
We use Bloch oscillations to transfer coherently many photon momenta to atoms. Then we can measure accurately the ratio h/m_Rb and deduce the fine structure constant alpha. The velocity variation due ...to the Bloch oscillations is measured thanks to Raman transitions. In a first experiment, two Raman \(\pi\) pulses are used to select and measure a very narrow velocity class. This method yields to a value of the fine structure constant alpha^{-1}= 137.035 998 84 (91) with a relative uncertainty of about 6.6 ppb. More recently we use an atomic interferometer consisting in two pairs of pi/2 pulses. We present here the first results obtained with this method.
In this paper we present a short overview of atom interferometry based on light pulses. We discuss different implementations and their applications for high precision measurements. We will focus on ...the determination of the ratio h/m of the Planck constant to an atomic mass. The measurement of this quantity is performed by combining Bloch oscillations of atoms in a moving optical lattice with a Ramsey-Bordé interferometer.
Radiative deexcitation (RD) of the metastable 2S state of muonic protium and deuterium atoms has been observed. In muonic protium, we improve the precision on lifetime and population (formation ...probability) values for the short-lived {\mu}p(2S) component, and give an upper limit for RD of long-lived {\mu}p(2S) atoms. In muonic deuterium at 1 hPa, 3.1 +-0.3 % of all stopped muons form {\mu}d(2S) atoms. The short-lived 2S component has a population of 1.35 +0.57 -0.33 % and a lifetime of {\tau}_short({\mu}d) = 138 +32 -34 ns. We see evidence for RD of long-lived {\mu}d(2S) with a lifetime of {\tau}_long({\mu}d) = 1.15 +0.75 -0.53 {\mu}s. This is interpreted as formation and decay of excited muonic molecules.
An obvious determination of the acceleration of gravity g can be deduced from
the measurement of the velocity of falling atoms using a pi-pi pulses sequence
of stimulated Raman transitions. By using ...a vertical standing wave to hold
atoms against gravity, we expect to improve the relative accuracy by increasing
the upholding time in the gravity field and to minimize the systematic errors
induced by inhomogeneous fields, owing to the very small spatial amplitude of
the atomic center-of-mass wavepacket periodic motion. We also propose to use
such an experimental setup nearby a Watt balance. By exploiting the g/h (h is
the Planck constant) dependence of the Bloch frequency, this should provide a
way to link a macroscopic mass to an atomic mass.
We use Bloch oscillations to accelerate coherently Rubidium atoms. The
variation of the velocity induced by this acceleration is an integer number
times the recoil velocity due to the absorption of ...one photon. The measurement
of the velocity variation is achieved using two velocity selective Raman
pi-pulses: the first pulse transfers atoms from the hyperfine state 5S1/2 |F=2,
mF=0> to 5S1/2, |F=1, mF = 0> into a narrow velocity class. After the
acceleration of this selected atomic slice, we apply the second Raman pulse to
bring the resonant atoms back to the initial state 5S1/2, |F=2, mF = 0>. The
populations in (F=1 and F=2) are measured separately by using a one-dimensional
time-of-flight technique. To plot the final velocity distribution we repeat
this procedure by scanning the Raman beam frequency of the second pulse. This
two pi-pulses system constitutes then a velocity sensor. Any noise in the
relative phase shift of the Raman beams induces an error in the measured
velocity. In this paper we present a theoretical and an experimental analysis
of this velocity sensor, which take into account the phase fluctuations during
the Raman pulses.
A very precise measurement of the Rydberg constant is performed using a direct-frequency comparison of the 2S-8S and 2S-8D two-photon transitions in atomic hydrogen with the difference of two optical ...standards connected to a frequency chain.< >
Physical Review Letters 96 (2006) 033001 We report an accurate measurement of the recoil velocity of Rb atoms based on
Bloch oscillations in a vertical accelerated optical lattice. We transfer about
...900 recoil momenta with an efficiency of 99.97 % per recoil. A set of 72
measurements of the recoil velocity, each one with a relative uncertainty of
about 33 ppb in 20 min integration time, leads to a determination of the fine
structure constant alpha with a statistical relative uncertainty of 4.4 ppb.
The detailed analysis of the different systematic errors yields to a relative
uncertainty of 6.7 ppb. The deduced value of 1/alpha is 137.03599878(91).
We report a new experimental scheme which combines atom interferometry with Bloch oscillations to provide a new measurement of the ratio \(h/m_{\mathrm{Rb}}\). By using Bloch oscillations, we impart ...to the atoms up to 1600 recoil momenta and thus we improve the accuracy on the recoil velocity measurement. The deduced value of \(h/m_{\mathrm{Rb}}\) leads to a new determination of the fine structure constant \(\alpha^{-1}=137.035 999 45 (62)\) with a relative uncertainty of \(4.6\times 10^{-9}\). The comparison of this result with the value deduced from the measurement of the electron anomaly provides the most stringent test of QED.
