Limits on Exotic Long-Range Spin-Spin Interactions of Electrons

Heckel, B. R.; Terrano, W. A.; Adelberger, E. G.

doi:10.1103/physrevlett.111.151802

Cited by 45 publications

(75 citation statements)

References 11 publications

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“…In this section, we discuss how this effect manifests itself in the spin-polarized torsion balance at the University of Washington, and discuss strategies to search for the axion using this experiment [67][68][69][70].…”

Section: Torsion Pendulummentioning

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: Torsion Pendulummentioning

confidence: 99%

Spin precession experiments for light axionic dark matter

et al. 2018

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“…Based on the estimates shown in Fig. 2, a measurement of needle precession averaged over ≈ 10 3 s could reach a sensitivity to exotic electron-spin-dependent couplings at an energy scale of ∼ 10 −26 eV, some five orders of magnitude beyond the best constraints to date [59,60].…”

mentioning

confidence: 99%

“…For example, the needle could be used to search for exotic spin-dependent interactions of electrons [59][60][61][62][63][64]. Based on the estimates shown in Fig.…”

mentioning

confidence: 99%

Precessing Ferromagnetic Needle Magnetometer

2016

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A ferromagnetic needle is predicted to precess about the magnetic field axis at a Larmor frequency Ω under conditions where its intrinsic spin dominates over its rotational angular momentum, N ≫ IΩ (I is the moment of inertia of the needle about the precession axis and N is the number of polarized spins in the needle). In this regime the needle behaves as a gyroscope with spin N maintained along the easy axis of the needle by the crystalline and shape anisotropy. A precessing ferromagnetic needle is a correlated system of N spins which can be used to measure magnetic fields for long times. In principle, by taking advantage of rapid averaging of quantum uncertainty, the sensitivity of a precessing needle magnetometer can far surpass that of magnetometers based on spin precession of atoms in the gas phase. Under conditions where noise from coupling to the environment is subdominant, the scaling with measurement time t of the quantum-and detectionlimited magnetometric sensitivity is t −3/2 . The phenomenon of ferromagnetic needle precession may be of particular interest for precision measurements testing fundamental physics.For an ensemble of N independent particles prepared in a coherent superposition of quantum states, the standard quantum limit (SQL) on the precision of a measurement of the phase φ is given byafter time t ≫ 1/Γ rel , where Γ rel is the relaxation rate of the coherence. Equation (1) represents a random walk in phase with step size 1/ √ N consisting of Γ rel t steps. In cases where the goal is to measure a frequency Ω = φ/t, there is an analogous SQL on the precision of a frequency measurement,For a measurement subject to the SQL, the minimum possible measurement uncertainty is obtained when Γ rel is made as small as possible. In the limit where Γ rel → 0, the precision becomes constrained by the duration of the measurement, so in Eqs. (1) and (2), Γ rel is replaced by 1/t. However, if the particles' time evolution is correlated, the SQL can be circumvented for times shorter than the coherence time (1/Γ rel ) [2][3][4]. Extensive experimental efforts involving quantum entanglement, squeezed states, and quantum nondemolition (QND) measurement strategies have been made to take advantage of this potential improvement in measurement sensitivity [5][6][7][8]. In this Letter we draw attention to a system which can, in principle, surpass the SQL on measurement of spin precession in a different way: by rapid averaging of quantum uncertainty.In particular, we consider the measurement of magnetic fields. The most precise magnetic field measurements are based on the techniques of optical atomic magnetometry [9, 10]: N atomic spins are optically polarized and their precession in a magnetic field B is measured using optical rotation of probe light [11]. Depending on its magnitude, the value of B is either extracted from measurement of the Larmor frequency Ω = gµ B B/ or the accrued spin precession angle φ = Ωt if φ ≪ 1 during the measurement time t (g is the Landé g-factor and µ B is the Bohr magneton). Optica...

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“…3 shows the sensitivity to interactions between two polarized electrons in DyIG and the cell which are independent of the velocity, V 2 , V 3 and V 11 . The present experimental constraints of these interactions for two polarized electrons were obtained from torsion pendulum [16,20,21] and paramagnetic salt [24] measurements. The estimation shows that the SERF magnetometer has no advantage for V 3 but can be sensitive to the new phase space of V 2 and V 11 .…”

Section: −18mentioning

confidence: 99%

“…The detection of spin-dependent interactions, therefore, will enable to distinguish the axion from the scalar boson [15]. The static spin-dependent interactions have been carefully investigated for polarized electrons: experiments with a torsion pendulum [16][17][18][19][20][21] and paramagnetic salt [22][23][24] and for nucleons: measurements of precession frequency of atomic gases [25][26][27][28][29]; experiments with an ion trap [30] and neutron bound states [31,32]; spinrelaxation measurements of polarized particles [33][34][35][36]. On the other hand, the experimental constraints on the interactions dependent on both spins and the relative velocity are very few.…”

mentioning

confidence: 99%

Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometer

2016

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We propose a novel experimental approach to explore exotic spin-dependent interactions using a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive non-cryogenic magneticfield sensor. This approach studies the interactions between optically polarized electron spins located inside a vapor cell of the SERF magnetometer and unpolarized or polarized particles of external solid-state objects. The coupling of spin-dependent interactions to the polarized electron spins of the magnetometer induces the tilt of the electron spins, which can be detected with high sensitivity by a probe laser beam similarly as an external magnetic field. We estimate that by moving unpolarized or polarized objects next to the SERF Rb vapor cell, the experimental limit to the spin-dependent interactions can be significantly improved over existing experiments, and new limits on the coupling strengths can be set in the interaction range below 10 −2 m.Recently, exotic spin-dependent interactions, predicted by string theories and many theoretical extensions of the Standard Model of particle physics [1][2][3], have attracted much attention in the community of physicists. Such theories are associated with the spontaneous breaking of continuous symmetries, leading to massless or very light Nambu-Goldston bosons [4][5][6], such as the axion [7], and axion-like-particles (ALPs) [2,8], which are candidates for cold dark matter [9,10]. These exotic particles are bosons and can weakly couple with ordinary particles, such as leptons or baryons. Moody and Wilczek [11] first proposed three possible types of interactions between polarized and unpolarized particles, which were later expanded by Dobrescu and Mocioiu [12] with the inclusion of the terms dependent on the relative velocity between the two interacting particles. A general classification of the interactions between particles contains sixteen types of structure of operators: fifteen of them depend on the spin of at least one of the particles and seven depend on the relative velocity of the particles. In this paper, we show a new experimental method to explore all the fifteen exotic spin-dependent interactions.The possible exotic spin-dependent interactions between polarized and unpolarized particles are (in SI units, where m p is the mass of the polarized particles,σ i is the spin vector of the i th polarized particle while σ i = σ i /2, is Planck's constant,r = r/r is a unit vector in the direction between the polarized and unpolarized particles, v is their relative velocity, c is the speed of light in vacuum, and λ is the interaction range.There are nine interactions between two polarized particles, three of which are not dependent of the relative velocity of the particles v,

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Limits on Exotic Long-Range Spin-Spin Interactions of Electrons

Cited by 45 publications

References 11 publications

Spin precession experiments for light axionic dark matter

Spin precession experiments for light axionic dark matter

Precessing Ferromagnetic Needle Magnetometer

Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometer

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