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Title: Limit on the Temporal Variation of the Fine-Structure Constant Using Atomic Dysprosium

Abstract

Over 8 months, we monitored transition frequencies between nearly degenerate, opposite-parity levels in two isotopes of atomic dysprosium (Dy). These frequencies are sensitive to variation of the fine-structure constant ({alpha}) due to relativistic corrections of opposite sign for the opposite-parity levels. In this unique system, in contrast to atomic-clock comparisons, the difference of the electronic energies of the opposite-parity levels can be monitored directly utilizing a rf electric-dipole transition between them. Our measurements show that the frequency variation of the 3.1-MHz transition in {sup 163}Dy and the 235-MHz transition in {sup 162}Dy are 9.0{+-}6.7 Hz/yr and -0.6{+-}6.5 Hz/yr, respectively. These results provide a rate of fractional variation of {alpha} of (-2.7{+-}2.6)x10{sup -15} yr{sup -1} (1{sigma}) without assumptions on constancy of other fundamental constants, indicating absence of significant variation at the present level of sensitivity.

Authors:
; ;  [1]; ; ;  [2];  [1];  [3]
  1. Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300 (United States)
  2. Physics Division, Los Alamos National Laboratory, P-23, MS-H803, Los Alamos, New Mexico 87545 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
20861630
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevLett.98.040801; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; COMPARATIVE EVALUATIONS; CORRECTIONS; DYSPROSIUM; DYSPROSIUM 162; DYSPROSIUM 163; E1-TRANSITIONS; FINE STRUCTURE; FUNDAMENTAL CONSTANTS; MHZ RANGE; PARITY; RELATIVISTIC RANGE

Citation Formats

Cingoez, A., Lapierre, A., Leefer, N., Nguyen, A.-T., Lamoreaux, S. K., Torgerson, J. R., Budker, D., and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720. Limit on the Temporal Variation of the Fine-Structure Constant Using Atomic Dysprosium. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.040801.
Cingoez, A., Lapierre, A., Leefer, N., Nguyen, A.-T., Lamoreaux, S. K., Torgerson, J. R., Budker, D., & Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720. Limit on the Temporal Variation of the Fine-Structure Constant Using Atomic Dysprosium. United States. doi:10.1103/PHYSREVLETT.98.040801.
Cingoez, A., Lapierre, A., Leefer, N., Nguyen, A.-T., Lamoreaux, S. K., Torgerson, J. R., Budker, D., and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720. Fri . "Limit on the Temporal Variation of the Fine-Structure Constant Using Atomic Dysprosium". United States. doi:10.1103/PHYSREVLETT.98.040801.
@article{osti_20861630,
title = {Limit on the Temporal Variation of the Fine-Structure Constant Using Atomic Dysprosium},
author = {Cingoez, A. and Lapierre, A. and Leefer, N. and Nguyen, A.-T. and Lamoreaux, S. K. and Torgerson, J. R. and Budker, D. and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720},
abstractNote = {Over 8 months, we monitored transition frequencies between nearly degenerate, opposite-parity levels in two isotopes of atomic dysprosium (Dy). These frequencies are sensitive to variation of the fine-structure constant ({alpha}) due to relativistic corrections of opposite sign for the opposite-parity levels. In this unique system, in contrast to atomic-clock comparisons, the difference of the electronic energies of the opposite-parity levels can be monitored directly utilizing a rf electric-dipole transition between them. Our measurements show that the frequency variation of the 3.1-MHz transition in {sup 163}Dy and the 235-MHz transition in {sup 162}Dy are 9.0{+-}6.7 Hz/yr and -0.6{+-}6.5 Hz/yr, respectively. These results provide a rate of fractional variation of {alpha} of (-2.7{+-}2.6)x10{sup -15} yr{sup -1} (1{sigma}) without assumptions on constancy of other fundamental constants, indicating absence of significant variation at the present level of sensitivity.},
doi = {10.1103/PHYSREVLETT.98.040801},
journal = {Physical Review Letters},
number = 4,
volume = 98,
place = {United States},
year = {Fri Jan 26 00:00:00 EST 2007},
month = {Fri Jan 26 00:00:00 EST 2007}
}
  • It has been proposed that the radio-frequency electric-dipole (E1) transition between two nearly degenerate opposite-parity states in atomic dysprosium should be highly sensitive to possible temporal variation of the fine-structure constant ({alpha}) [V. A. Dzuba, V. V. Flambaum, and J. K. Webb, Phys. Rev. A 59, 230 (1999)]. We analyze here an experimental realization of the proposed search in progress in our laboratory, which involves monitoring the E1 transition frequency over a period of time using direct frequency counting techniques. We estimate that a statistical sensitivity of |{alpha}/{alpha}|{approx}10{sup -18}/yr may be achieved and discuss possible systematic effects that may limitmore » such a measurement.« less
  • A comparison of different atomic frequency standards over time can be used to perform a measurement of the present value of the temporal derivative of the fine structure constant {alpha} in a model-independent way without assumptions on constancy or variability of other parameters. We have measured an optical transition frequency at 688 THz in Yb+ with a cesium atomic clock at two times separated by 2.8 years and find that a variation of this frequency can be excluded within a 1{sigma} relative uncertainty of 4.4{center_dot}10-15 yr-1. Combined with recently published values for the constancy of other transition frequencies this measurementmore » provides a limit on the present variability of {alpha} at the level of 2.0{center_dot}10-15 yr-1. Constraints are also derived for the drift rates of other fundamental constants like the electron/proton mass ratio and the proton g-factor.« less
  • Radio-frequency E1 transitions between nearly degenerate, opposite-parity levels of atomic dysprosium (Dy) were monitored over an 8-month period to search for a variation in the fine-structure constant {alpha}. During this time period, data were taken at different points in the gravitational potential of the Sun. The data are fitted to the variation in the gravitational potential yielding a value of (-8.7{+-}6.6)x10{sup -6} for k{sub {alpha}}, the variation of {alpha} in a changing gravitational potential. This value gives the first laboratory limit independent of assumptions regarding other fundamental constants. In addition, our value of k{sub {alpha}} combined with other experimental constraintsmore » is used to extract the first limits on k{sub e} and k{sub q}. These coefficients characterize the variation of m{sub e}/m{sub p} and m{sub q}/m{sub p} in a changing gravitational potential, where m{sub e}, m{sub p}, and m{sub q} are electron, proton, and quark masses. The results are k{sub e}=(4.9{+-}3.9)x10{sup -5} and k{sub q}=(6.6{+-}5.2)x10{sup -5}. All these results indicate the absence of significant variation at the present level of sensitivity.« less
  • We show that the relative effect of variation of the fine-structure constant in microwave transitions between very close and narrow rotational-hyperfine levels may be enhanced 2-3 orders of magnitude in diatomic molecules with unpaired electrons like LaS, LaO, LuS, LuO, YbF, and similar molecular ions. The enhancement is result of cancellation between the hyperfine and rotational intervals.
  • The relative effects of the variation of the fine structure constant {alpha}=e{sup 2}/({Dirac_h}/2{pi})c and the dimensionless strong interaction parameter m{sub q}/{lambda}{sub QCD} are enhanced by 5-6 orders of magnitude in a very narrow ultraviolet transition between the ground and the first excited states in the {sup 229}Th nucleus. It may be possible to investigate this transition with laser spectroscopy. Such an experiment would have the potential of improving the sensitivity to temporal variation of the fundamental constants by many orders of magnitude.