New Limits on Coupling of Fundamental Constants to Gravity UsingSr87Optical Lattice Clocks

Abstract

The 1S0-3P0 clock transition frequency nuSr in neutral 87Sr has been measured relative to the Cs standard by three independent laboratories in Boulder, Paris, and Tokyo over the last three years. The agreement on the 1 x 10(-15) level makes nuSr the best agreed-upon optical atomic frequency. We combine periodic variations in the 87Sr clock frequency with 199Hg+ and H-maser data to test local position invariance by obtaining the strongest limits to date on gravitational-coupling coefficients for the fine-structure constant alpha, electron-proton mass ratio mu, and light quark mass. Furthermore, after 199Hg+, 171Yb+, and H, we add 87Sr as the fourth optical atomic clock species to enhance constraints on yearly drifts of alpha and mu.

Experimental realization of an optical second with strontium lattice clocks

“…4c). This fit is still compatible with no variation of the constants, but with an eight-fold increased resolution compared to the previous measurements 44 . These laboratory tests of fundamental physics involve optical-microwave as well as optical-optical 5 and microwave-microwave 45 frequency ratios.…”

Strong coupling on a forbidden transition in strontium and nondestructive atom counting

“…This observation demonstrates that despite the relative feebleness of the transition, the tools of cavity-QED can now be applied to a system of extreme interest for quantum metrology [14]. Example technologies include optical lattice clocks [15][16][17] and ultra-narrow lasers [6][7][8][9], along with their associated broad range of potential applications such defining the second [14,18], quantum many-body simulations [19], measuring gravitational potentials [20] and gravity waves [21], and searches for physics beyond the standard model [22,23].One relevant application of this newly achieved regime is for state-selective, non-destructive counting of strontium atoms. Such counting has been used to generate highly spin-squeezed states [1,24] that surpass the standard quantum limit on phase estimation [25][26][27].…”

Searching for chameleon-like scalar fields with the ammonia method

“…Data obtained from high precision frequency measurements in laboratory experiments with atomic clocks and from astronomical observations provide only upper limits. For example, laboratory experiments have delivered the following results: fractional temporal variations in μ are restricted to a level ofμ/μ = (3.8 ± 5.6) × 10 −14 yr −1 (Shelkovnikov et al 2008), anḋ μ/μ = (1.6 ± 1.7) × 10 −15 yr −1 (Blatt et al 2008), whereas the current level for α isα/α = (−1.6 ±2.3) ×10 −17 yr −1 (Rosenband et al 2008). Here Δμ and Δα are the relative changes between the values measured at two different epochs.…”