Thomas P Heavner

Publications (5)1.69 Total impact

• Article: First-Order Sideband Pulling in Atomic Frequency Standards.

  Jon H. Shirley, Thomas P. Heavner, Steven R. Jefferts
  IEEE T. Instrumentation and Measurement. 01/2009; 58:1241-1246.
• Source

  Available from: ArXiv

  Article: The absolute frequency of the 87Sr optical clock transition

  Gretchen K. Campbell, Andrew D Ludlow, Sebastian Blatt, Jan W. Thomsen, Michael J Martin, Marcio H. G. de Miranda, Tanya Zelevinsky, Martin M. Boyd, Jun Ye, Scott A. Diddams, Thomas P Heavner, Thomas E. Parker, Steven R Jefferts
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  ABSTRACT: The absolute frequency of the 1S0-3P0 clock transition of 87Sr has been measured to be 429 228 004 229 873.65 (37) Hz using lattice-confined atoms, where the fractional uncertainty of 8.6x10-16 represents one of the most accurate measurements of an atomic transition frequency to date. After a detailed study of systematic effects, which reduced the total systematic uncertainty of the Sr lattice clock to 1.5x10-16, the clock frequency is measured against a hydrogen maser which is simultaneously calibrated to the US primary frequency standard, the NIST Cs fountain clock, NIST-F1. The comparison is made possible using a femtosecond laser based optical frequency comb to phase coherently connect the optical and microwave spectral regions and by a 3.5 km fiber transfer scheme to compare the remotely located clock signals.
  04/2008;
• Source

  Available from: nist.gov

  Article: Microwave leakage-induced frequency shifts in the primary frequency standards NIST-F1 and IEN-CSF1.

  Jon H Shirley, Filippo Levi, Thomas P Heavner, Davide Calonico, Dai-Hyuk Yu, Steve R Jefferts
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  ABSTRACT: In atomic fountain primary frequency standards, the atoms ideally are subjected to microwave fields resonant with the ground-state, hyperfine splitting only during the two pulses of Ramsey's separated oscillatory field measurement scheme. As a practical matter, however, stray microwave fields can be present that shift the frequency of the central Ramsey fringe and, therefore, adversely affect the accuracy of the standard. We investigate these uncontrolled stray fields here and show that the frequency errors can be measured, and indeed even the location within the standard determined by the behavior of the measured frequency with respect to microwave power in the Ramsey cavity. Experimental results that agree with the theory are presented as well.
  IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 01/2007; 53(12):2376-85. · 1.69 Impact Factor
• Article: Optical molasses loaded from a low-velocity intense source of atoms: an atom source for improved atomic fountains.

  Elizabeth A. Donley, Thomas P. Heavner, Steven R. Jefferts
  IEEE T. Instrumentation and Measurement. 01/2005; 54:1905-1910.
• Source

  Available from: nist.gov

  Article: Recent improvements in NIST-F1 and a resulting accuracy of δf/f=0.61×10

  Thomas P. Heavner, Steven R. Jefferts, Elizabeth A. Donley, Jon H. Shirley, Thomas E. Parker
  IEEE T. Instrumentation and Measurement. 01/2005; 54:842-845.