Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userHigh precision measurement of the 87Rb D-line tune-out wavelength
118
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We report an experimental measurement of a light wavelength at which the ac electric polarizability equals zero for 87Rb atoms in the F=2 ground hyperfine state. The experiment uses a condensate interferometer both to find this tune-out wavelength and to accurately determine the light polarization for it. The wavelength lies between the D1 and D2 spectral lines at 790.03235(3) nm. The measurement is sensitive to the tensor contribution to the polarizability, which has been removed so that the reported value is the zero of the scalar polarizability. The precision is fifty times better than previous tune-out wavelength measurements. Our result can be used to determine the ratio of matrix elements |<5P3/2||d||5S1/2>/<5P1/2||d||5S1/2>|^2 = 1.99219(3), a 100-fold improvement over previous experimental values. Both the tune-out wavelength and matrix element ratio are consistent with theoretical calculations, with uncertainty estimates for the theory about an order of magnitude larger than the experimental precision.
rate research
Read More
We present the first measurement for helium atoms of the tune-out wavelength at which the atomic polarizability vanishes. We utilise a novel, highly sensitive technique for precisely measuring the effect of variations in the trapping potential of confined metastable ($2^{3}S_{1}$) helium atoms illuminated by a perturbing laser light field. The measured tune-out wavelength of 413.0938($9_{Stat.}$)($20_{Syst.}$) nm compares well with the value predicted by a theoretical calculation (413.02(9) nm) which is sensitive to finite nuclear mass, relativistic, and quantum electro-dynamic (QED) effects. This provides motivation for more detailed theoretical investigations to test QED.
The spin-magnetic moment of the proton $mu_p$ is a fundamental property of this particle. So far $mu_p$ has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin-transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the protons cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particles magnetic moment in units of the nuclear magneton $mu_p=2.792847350(9)mu_N$. This measurement outperforms previous Penning trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty year old indirect measurement, in which significant theoretical bound state corrections were required to obtain $mu_p$, by a factor of 3. By application of this method to the antiproton magnetic moment $mu_{bar{p}}$ the fractional precision of the recently reported value can be improved by a factor of at least 1000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.
The workhorse of atomic physics, quantum electrodynamics, is one of the best-tested theories in physics. However recent discrepancies have shed doubt on its accuracy for complex atomic systems. To facilitate the development of the theory further we aim to measure transition dipole matrix elements of metastable helium (He*) (the ideal 3 body test-bed) to the highest accuracy thus far. We have undertaken a measurement of the `tune-out wavelength which occurs when the contributions to the dynamic polarizability from all atomic transitions sum to zero; thus illuminating an atom with this wavelength of light then produces no net energy shift. This provides a strict constraint on the transition dipole matrix elements without the complication and inaccuracy of other methods. Using a novel atom-laser based technique we have made the first measurement of the tune-out wavelength in metastable helium between the $3^{3}P_{1,2,3}$ and $2^{3}P_{1,2,3}$ states at 413.07(2) nm which compares well with the predicted valuecite{Mitroy2013} of 413.02(9) nm. We have additionally developed many of the methods necessary to improve this measurement to the 100 fm level of accuracy where it will form the most accurate determination of transition rate information ever made in He* and provide a stringent test for atomic QED simulations. We believe this measurement to be one of the most sensitive ever made of an optical dipole potential, able to detect changes in potentials of $sim$200 pK and is widely applicable to other species and areas of atom optics.
Despite quantum electrodynamics (QED) being one of the most stringently tested theories underpinning modern physics, recent precision atomic spectroscopy measurements have uncovered several small discrepancies between experiment and theory. One particularly powerful experimental observable that tests QED independently of traditional energy level measurements is the `tune-out frequency, where the dynamic polarizability vanishes and the atom does not interact with applied laser light. In this work, we measure the `tune-out frequency for the $2^{3!}S_1$ state of helium between transitions to the $2^{3!}P$ and $3^{3!}P$ manifolds and compare it to new theoretical QED calculations. The experimentally determined value of $725,736,700,$$(40_{mathrm{stat}},260_{mathrm{syst}})$ MHz is within ${sim} 2.5sigma$ of theory ($725,736,053(9)$ MHz), and importantly resolves both the QED contributions (${sim} 30 sigma$) and novel retardation (${sim} 2 sigma$) corrections.
We present direct measurements of the hyperfine splitting of Rydberg states in rubidium 87 using Electromagnetically Induced Transparency (EIT) spectroscopy in a room-temperature vapour cell. With this method, and in spite of Doppler-broadening, line-widths of 3.7 MHz FWHM, i.e. significantly below the intermediate state natural linewidth are reached. This allows resolving hyperfine splittings for Rydberg s-states with n=20...24. With this method we are able to determine Rydberg state hyperfine splittings with an accuracy of approximately 100 kHz. Ultimately our method allows accuracies of order 5 kHz to be reached. Furthermore we present a direct measurement of hyperfine-resolved Rydberg state Stark-shifts. These results will be of great value for future experiments relying on excellent knowledge of Rydberg-state energies and
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
