New limits on variation of the fine-structure constant using atomic dysprosium.
New limits on variation of the fine-structure constant using atomic dysprosium.
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DOI：
10.1103/physrevlett.111.060801
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发表时间：
2013-04
影响因子：
8.6
通讯作者：
N. Leefer;Carsten Weber;A. Cingöz;J. Torgerson;D. Budker;D. Budker
中科院分区：
文献类型：
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作者：
N. Leefer;Carsten Weber;A. Cingöz;J. Torgerson;D. Budker;D. Budker
本文报道了镝原子近简并反宇称激发态之间的射频跃迁光谱。理论计算预测，由于相反宇称能级的相反符号的大相对论修正，这些态对精细结构常数α的变化非常敏感。近简并性降低了对α变化施加约束所需的相对精度，这与世界上最好的原子钟所获得的结果具有竞争力。此外，Dy的几种丰富同位素的存在允许抑制共模系统误差的同位素比较。164 Dy的754-MHz跃迁和162 Dy的235-MHz跃迁的频率是在两年的时间内测量的。α的线性变化为α·/α=（-5.8 <$6.9（[1σ]））×10（-17）yr（-1），与零一致。相同的数据用于约束无因次参数kα，该参数表征α与变化的引力势的可能耦合。我们发现kα=（-5.5 <$5.2（[1σ]））×10（-7），基本上与零一致，是迄今为止最好的约束。
We report on the spectroscopy of radio-frequency transitions between nearly degenerate, opposite-parity excited states in atomic dysprosium (Dy). Theoretical calculations predict that these states are very sensitive to variation of the fine-structure constant α owing to large relativistic corrections of opposite sign for the opposite-parity levels. The near degeneracy reduces the relative precision necessary to place constraints on variation of α, competitive with results obtained from the best atomic clocks in the world. Additionally, the existence of several abundant isotopes of Dy allows isotopic comparisons that suppress common-mode systematic errors. The frequencies of the 754-MHz transition in 164Dy and 235-MHz transition in 162Dy are measured over the span of two years. The linear variation of α is α·/α=(-5.8±6.9([1σ]))×10(-17) yr(-1), consistent with zero. The same data are used to constrain the dimensionless parameter kα characterizing a possible coupling of α to a changing gravitational potential. We find that kα=(-5.5±5.2([1σ]))×10(-7), essentially consistent with zero and the best constraint to date.