Allmendinger<i>et al.</i>Reply:

Allmendinger, F.; Schmidt, Ulrich; Heil, W.; Karpuk, S.; Scharth, A.; Sobolev, Yu.; Tullney, K.

doi:10.1103/physrevlett.113.188902

Cited by 36 publications

(61 citation statements)

References 6 publications

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“…2. More recently, this experiment has published a stricter bound on this coupling [74], but these results are currently still under review. This measurement was limited by systematic drifts in the weighted precession frequency, but for future iterations, we assume that these systematics can be FIG.…”

Section: Low-frequency Analysismentioning

confidence: 99%

Spin precession experiments for light axionic dark matter

et al. 2018

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Axionlike particles are promising candidates to make up the dark matter of the Universe, but it is challenging to design experiments that can detect them over their entire allowed mass range. Dark matter in general, and, in particular, axionlike particles and hidden photons, can be as light as roughly 10 −22 eV (∼10 −8 Hz), with astrophysical anomalies providing motivation for the lightest masses ("fuzzy dark matter"). We propose experimental techniques for direct detection of axionlike dark matter in the mass range from roughly 10 −13 eV (∼10 2 Hz) down to the lowest possible masses. In this range, these axionlike particles act as a time-oscillating magnetic field coupling only to spin, inducing effects such as a timeoscillating torque and periodic variations in the spin-precession frequency with the frequency and direction of these effects set by the axion field. We describe how these signals can be measured using existing experimental technology, including torsion pendulums, atomic magnetometers, and atom interferometry. These experiments demonstrate a strong discovery capability, with future iterations of these experiments capable of pushing several orders of magnitude past current astrophysical bounds.

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Section: Low-frequency Analysismentioning

confidence: 99%

Spin precession experiments for light axionic dark matter

et al. 2018

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“…Applications in precision measurements began with NMR gyros [5] and have continued with fundamental symmetry tests using multiple cell free induction decay [6], dual-species masers [7,8], selfcompensating co-magnetometers [9], NMR oscillators [10], and free spin-precession co-magnetometers [11][12][13][14].…”

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confidence: 99%

“…With two-species, one species can be used to remove magnetic field noise, leaving the other sensitive to non-magnetic interactions. This strategy is used in various forms in many experiments [5,7,8,[11][12][13][14]. The resulting effective frequency noise δx resulting from some non-magnetic interaction H = hx is of order δx = 1 + γ …”

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confidence: 99%

Synchronous Spin-Exchange Optical Pumping

et al. 2015

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We describe a new approach to precision NMR with hyperpolarized gases designed to mitigate NMR frequency shifts due to the alkali spin exchange field. The electronic spin polarization of optically pumped alkali atoms is square-wave modulated at the noble-gas NMR frequency and oriented transverse to the DC Fourier component of the NMR bias field. Noble gas NMR is driven by spin-exchange collisions with the oscillating electron spins. On resonance, the time-average torque from the oscillating spin-exchange field produced by the alkali spins is zero. Implementing the NMR bias field as a sequence of alkali 2π-pulses enables synchronization of the alkali and noble gas spins despite a 1000-fold discrepancy in gyromagnetic ratio. We demonstrate this method with Rb and Xe, and observe novel NMR broadening effects due to the transverse oscillating spin exchange field. When uncompensated, the spin-exchange field at high density broadens the NMR linewidth by an order of magnitude, with an even more dramatic suppression (up to 70x) of the phase shift between the precessing alkali and Xe polarizations. When we introduce a transverse compensation field, we are able to eliminate the spin-exchange broadening and restore the usual NMR phase sensitivity. The projected quantum-limited sensitivity is better than 1 nHz// √ Hz.The ability to produce highly magnetized noble gases via spin-exchange collisions with spin-polarized alkali atoms [1] has greatly impacted scientific studies of magnetic resonance imaging [2], high-energy nuclear physics with spin-polarized targets [3], and chemical physics [4]. Applications in precision measurements began with NMR gyros [5] and have continued with fundamental symmetry tests using multiple cell free induction decay [6], dual-species masers [7,8], selfcompensating co-magnetometers [9], NMR oscillators [10], and free spin-precession co-magnetometers [11][12][13][14].Some of these approaches [5, 9-11, 14] take advantage of enhanced NMR detection by the embedded alkali magnetometer. The alkali and noble-gas spin ensembles experience enhanced polarization sensitivity due to the Fermi-contact interaction during collisions between the two species. The effective Fermi-contact fields experienced by the two species arewhere S, K are the electron and nuclear spin operators, n S , n K the atomic densities, µ K the nuclear magnetic moment of the noble gas, µ B the Bohr magneton, and the atomic g-factor g ≈ 2. The frequency-shift enhancement factor κ [15,16] was recently measured to be 493 ± 31 [17] for RbXe. Thus the detected NMR field B SK is ∼500× larger for the embedded magnetometer than for any external sensor. This seemingly decisive advantage comes with the cost of similarly enhancing the B KS field due to the spin-polarized alkali atoms, 190 µG at 2n S S = 10 13 cm −3 . In typical longitudinally polarized NMR this field produces large frequency shifts of order 0.1 Hz. One approach for mitigating this effect is to compare two Xe isotopes [5,11], for which the enhancement factors are equal to about 0....

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“…The interaction (42), like (1), produces sidereal shifts of the energy levels in atomic and nuclear systems, but only in the presence of an external magnetic field, and can be sought for in a similar manner to the coupling (1) via sidereal modulations of transition frequencies [1][2][3][4][5][6][7][8][9][10][11]. Existing experiments were performed in non-zero magnetic fields and so we can extract limits on |d ⊥ | from the magnetic field strengths used in these experiments and existing limits on |b| (Table I).…”

Section: Other Testsmentioning

confidence: 99%

Tests ofCPTand Lorentz symmetry from muon anomalous magnetic dipole moment

2014

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We derive the relativistic factor for splitting of the g-factors of a fermion and its anti-fermion partner, which is important for placing constraints on dimension-5, CP T -odd and Lorentz-invarianceviolating interactions from experiments performed in a cyclotron. From existing data, we extract limits (1σ) on the coupling strengths of the temporal component, f 0 , of a background field (including the field amplitude), which is responsible for such g-factor splitting, with an electron, proton, and muon: |f 0 e | < 2.3 × 10 −12 µB, |f 0 p | < 4 × 10 −9 µB, and |f 0 µ | < 8 × 10 −11 µB, respectively, in the laboratory frame. From existing data, we also extract limits on the coupling strengths of the spatial components, d⊥ , of related dimension-5 interactions of a background field with an electron, proton, neutron, and muon: |d ⊥ e | 10 −9 µB, |d ⊥ p | 10 −9 µB, |d ⊥ n | 10 −10 µB, and |d ⊥ µ | 10 −9 µB, respectively, in the laboratory frame.

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Allmendingeret al.Reply:

Cited by 36 publications

References 6 publications

Spin precession experiments for light axionic dark matter

Spin precession experiments for light axionic dark matter

Synchronous Spin-Exchange Optical Pumping

Tests ofCPTand Lorentz symmetry from muon anomalous magnetic dipole moment

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