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The First Measurement of the $2^{3}S_{1} \rightarrow 3^{3}P - 2^{3}P$ Tune-Out Wavelength in He*

B. M. Henson

Published Aug 28, 2017• 0 citations
OpenAlex

Abstract

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 value\cite{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.

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The First Measurement of the $2^{3\!}S_1 - 2^{3\!}P / 3^{3\!}P$ Tune-Out Wavelength in He*

B. M. Henson

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 value [PhysRevA.88.052515] 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.

arXiv:1708.08200•Aug 28, 2017•0 citations

Tune-out wavelengths for metastable helium

Jim Mitroy, Li-Yan Tang

The six longest tune-out wavelengths for the He($1s2s{\phantom{\rule{4pt}{0ex}}}^{3}{S}_{1}^{e}$) metastable state are determined by explicit calculation. The tune-out wavelength at 413.02 nm is expected to be sensitive to finite mass, relativistic, and quantum electrodynamic effects upon the transition matrix elements and its measurement would provide a nonenergy test of fundamental atomic structure theory.

Physical Review A•Nov 20, 2013•43 citations

Experimental Determination of the Helium 2 P13–1 S01 Transition Rate

R. G. Dall, K. G. H. Baldwin, L. J. Byron +1 more

We present the first experimental determination of the $2\text{ }^{3}P_{1}--1\text{ }^{1}S_{0}$ transition rate in helium and compare this measurement with theoretical quantum-electrodynamic predictions. The experiment exploits the very long ($\ensuremath{\sim}1\text{ }\text{ }\mathrm{\text{minute}}$) confinement times obtained for atoms magneto-optically trapped in an apparatus used to create a Bose-Einstein condensate of metastable ($2\text{ }^{3}S_{1}$) helium. The $2\text{ }^{3}P_{1}--1\text{ }^{1}S_{0}$ transition rate is measured directly from the decay rate of the cold atomic cloud following 1083 nm laser excitation from the $2\text{ }^{3}S_{1}$ to the $2\text{ }^{3}P_{1}$ state, and from accurate knowledge of the $2\text{ }^{3}P_{1}$ population. The value obtained is $177\ifmmode\pm\else\textpm\fi{}8\text{ }\text{ }{\mathrm{s}}^{\ensuremath{-}1}$, which agrees very well with theoretical predictions, and has an accuracy that compares favorably with measurements for the same transition in heliumlike ions higher in the isoelectronic sequence.

Physical Review Letters•Jan 15, 2008•20 citations

Measurement of the tune-out wavelength for Cs133 at 880 nm

Apichayaporn Ratkata, Philip D. Gregory, Andrew D. Innes +6 more

We perform a measurement of the tune-out wavelength, ${\ensuremath{\lambda}}_{0}$, between the ${D}_{1}$, ${6}^{2}{S}_{1/2}\ensuremath{\rightarrow}{6}^{2}{P}_{1/2}$, and ${D}_{2}$, ${6}^{2}{S}_{1/2}\ensuremath{\rightarrow}{6}^{2}{P}_{3/2}$, transitions for $^{133}\mathrm{Cs}$ in the ground hyperfine state $(F=3,{m}_{F}=+3)$. At ${\ensuremath{\lambda}}_{0}$, the frequency-dependent scalar polarizability is zero leading to a zero scalar ac Stark shift. We measure the polarizability as a function of wavelength using Kapitza-Dirac scattering of a $^{133}\mathrm{Cs}$ Bose-Einstein condensate in a one-dimensional optical lattice, and determine the tune-out wavelength to be ${\ensuremath{\lambda}}_{0}=880.21790{(40)}_{\text{stat}}{(8)}_{\text{sys}}$ nm. From this measurement we determine the ratio of reduced matrix elements to be ${|\ensuremath{\langle}6{P}_{3/2}\ensuremath{\parallel}d\ensuremath{\parallel}6{S}_{1/2}\ensuremath{\rangle}|}^{2}/{|\ensuremath{\langle}6{P}_{1/2}\ensuremath{\parallel}d\ensuremath{\parallel}6{S}_{1/2}\ensuremath{\rangle}|}^{2}=1.9808(2)$. This represents an improvement of a factor of 10 over previous results derived from excited-state lifetime measurements. We use the present measurement as a benchmark test of high-precision theory.

arXiv:2110.00043•Physical Review A•Nov 22, 2021•15 citations

Obtaining Atomic Matrix Elements from Vector Tune-Out Wavelengths Using Atom Interferometry

Adam Fallon, Charles A. Sackett

Accurate values for atomic dipole matrix elements are useful in many areas of physics, and in particular for interpreting experiments such as atomic parity violation. Obtaining accurate matrix element values is a challenge for both experiment and theory. A new technique that can be applied to this problem is tune-out spectroscopy, which is the measurement of light wavelengths where the electric polarizability of an atom has a zero. Using atom interferometry methods, tune-out wavelengths can be measured very accurately. Their values depend on the ratios of various dipole matrix elements and are thus useful for constraining theory and broadening the application of experimental values. To date, tune-out wavelength measurements have focused on zeros of the scalar polarizability, but in general the vector polarizability also contributes. We show here that combined measurements of the vector and scalar polarizabilities can provide more detailed information about the matrix element ratios, and in particular can distinguish small contributions from the atomic core and the valence tail states. These small contributions are the leading error sources in current parity violation calculations for cesium.

arXiv:1603.09277•Atoms•Mar 30, 2016•12 citations

High-Precision Spectroscopy of the Forbidden 2 S13→2 P11 Transition in Quantum Degenerate Metastable Helium

Remy Notermans, W. Vassen

We have measured the forbidden $2\text{ }^{3}{S}_{1}\ensuremath{\rightarrow}2\text{ }^{1}{P}_{1}$ transition at 887 nm in a quantum degenerate gas of metastable $^{4}\mathrm{He}$ atoms confined in an optical dipole trap. The determined transition frequency is 338 133 594.4 (0.5) MHz, from which we obtain an ionization energy of the $2\text{ }^{1}{P}_{1}$ state of 814 709 148.6 (0.5) MHz. This ionization energy is in disagreement by $>3\ensuremath{\sigma}$ with the most accurate quantum electrodynamics calculations available. Our measurements also provide a new determination of the lifetime of the $2\text{ }^{1}{P}_{1}$ state of $0.551\text{ }(0.004{)}_{\text{stat}}\text{ }{(}_{\ensuremath{-}0.000}^{+0.013}{)}_{\text{syst}}\text{ }\text{ }\mathrm{ns}$, which is the most accurate determination to date and in excellent agreement with theory.

arXiv:1404.1759•Physical Review Letters•Jun 25, 2014•36 citations
The First Measurement of the 23S1→33P−23P2^{3}S_{1} \rightarrow 3^{3}P - 2^{3}P23S1​→33P−23P Tune-Out Wavelength in He*
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 33P1,2,33^{3}P_{1,2,3}33P1,2,3​ and 23P1,2,32^{3}P_{1,2,3}23P1,2,3​ states at 413.07(2) nm which compares well with the predicted value\cite{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.
The First Measurement of the 23 ⁣S1−23 ⁣P/33 ⁣P2^{3\!}S_1 - 2^{3\!}P / 3^{3\!}P23S1​−23P/33P Tune-Out Wavelength in He*
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 33P1,2,33^{3}P_{1,2,3}33P1,2,3​ and 23P1,2,32^{3}P_{1,2,3}23P1,2,3​ states at 413.07(2) nm which compares well with the predicted value [PhysRevA.88.052515] 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$200 pK and is widely applicable to other species and areas of atom optics.
The six longest tune-out wavelengths for the He(1s2s3S1e1s2s{\phantom{\rule{4pt}{0ex}}}^{3}{S}_{1}^{e}1s2s3S1e​) metastable state are determined by explicit calculation. The tune-out wavelength at 413.02 nm is expected to be sensitive to finite mass, relativistic, and quantum electrodynamic effects upon the transition matrix elements and its measurement would provide a nonenergy test of fundamental atomic structure theory.
We present the first experimental determination of the 2 3P1−−1 1S02\text{ }^{3}P_{1}--1\text{ }^{1}S_{0}2 3P1​−−1 1S0​ transition rate in helium and compare this measurement with theoretical quantum-electrodynamic predictions. The experiment exploits the very long ($\ensuremath{\sim}1\text{ }\text{ }\mathrm{\text{minute}}$) confinement times obtained for atoms magneto-optically trapped in an apparatus used to create a Bose-Einstein condensate of metastable (2 3S12\text{ }^{3}S_{1}2 3S1​) helium. The 2 3P1−−1 1S02\text{ }^{3}P_{1}--1\text{ }^{1}S_{0}2 3P1​−−1 1S0​ transition rate is measured directly from the decay rate of the cold atomic cloud following 1083 nm laser excitation from the 2 3S12\text{ }^{3}S_{1}2 3S1​ to the 2 3P12\text{ }^{3}P_{1}2 3P1​ state, and from accurate knowledge of the 2 3P12\text{ }^{3}P_{1}2 3P1​ population. The value obtained is $177\ifmmode\pm\else\textpm\fi{}8\text{ }\text{ }{\mathrm{s}}^{\ensuremath{-}1}$, which agrees very well with theoretical predictions, and has an accuracy that compares favorably with measurements for the same transition in heliumlike ions higher in the isoelectronic sequence.
We perform a measurement of the tune-out wavelength, ${\ensuremath{\lambda}}_{0}$, between the D1{D}_{1}D1​, ${6}^{2}{S}_{1/2}\ensuremath{\rightarrow}{6}^{2}{P}_{1/2}$, and D2{D}_{2}D2​, ${6}^{2}{S}_{1/2}\ensuremath{\rightarrow}{6}^{2}{P}_{3/2}$, transitions for 133Cs^{133}\mathrm{Cs}133Cs in the ground hyperfine state (F=3,mF=+3)(F=3,{m}_{F}=+3)(F=3,mF​=+3). At ${\ensuremath{\lambda}}_{0}$, the frequency-dependent scalar polarizability is zero leading to a zero scalar ac Stark shift. We measure the polarizability as a function of wavelength using Kapitza-Dirac scattering of a 133Cs^{133}\mathrm{Cs}133Cs Bose-Einstein condensate in a one-dimensional optical lattice, and determine the tune-out wavelength to be ${\ensuremath{\lambda}}_{0}=880.21790{(40)}_{\text{stat}}{(8)}_{\text{sys}}$ nm. From this measurement we determine the ratio of reduced matrix elements to be ${|\ensuremath{\langle}6{P}_{3/2}\ensuremath{\parallel}d\ensuremath{\parallel}6{S}_{1/2}\ensuremath{\rangle}|}^{2}/{|\ensuremath{\langle}6{P}_{1/2}\ensuremath{\parallel}d\ensuremath{\parallel}6{S}_{1/2}\ensuremath{\rangle}|}^{2}=1.9808(2)$. This represents an improvement of a factor of 10 over previous results derived from excited-state lifetime measurements. We use the present measurement as a benchmark test of high-precision theory.
Accurate values for atomic dipole matrix elements are useful in many areas of physics, and in particular for interpreting experiments such as atomic parity violation. Obtaining accurate matrix element values is a challenge for both experiment and theory. A new technique that can be applied to this problem is tune-out spectroscopy, which is the measurement of light wavelengths where the electric polarizability of an atom has a zero. Using atom interferometry methods, tune-out wavelengths can be measured very accurately. Their values depend on the ratios of various dipole matrix elements and are thus useful for constraining theory and broadening the application of experimental values. To date, tune-out wavelength measurements have focused on zeros of the scalar polarizability, but in general the vector polarizability also contributes. We show here that combined measurements of the vector and scalar polarizabilities can provide more detailed information about the matrix element ratios, and in particular can distinguish small contributions from the atomic core and the valence tail states. These small contributions are the leading error sources in current parity violation calculations for cesium.
We have measured the forbidden $2\text{ }^{3}{S}_{1}\ensuremath{\rightarrow}2\text{ }^{1}{P}_{1}$ transition at 887 nm in a quantum degenerate gas of metastable 4He^{4}\mathrm{He}4He atoms confined in an optical dipole trap. The determined transition frequency is 338 133 594.4 (0.5) MHz, from which we obtain an ionization energy of the 2 1P12\text{ }^{1}{P}_{1}2 1P1​ state of 814 709 148.6 (0.5) MHz. This ionization energy is in disagreement by $>3\ensuremath{\sigma}$ with the most accurate quantum electrodynamics calculations available. Our measurements also provide a new determination of the lifetime of the 2 1P12\text{ }^{1}{P}_{1}2 1P1​ state of $0.551\text{ }(0.004{)}_{\text{stat}}\text{ }{(}_{\ensuremath{-}0.000}^{+0.013}{)}_{\text{syst}}\text{ }\text{ }\mathrm{ns}$, which is the most accurate determination to date and in excellent agreement with theory.