New Limits on Anomalous Spin-Spin Interactions

Search for exotic spin-dependent interactions with a spin-based amplifier

“…We note that the overlapping spin ensemble (e.g., 129 Xe- 87 Rb) is also used in “self-compensating” comagnetometers ( 20 , 21 , 49 ); however, the present spin-based amplifier is quite different from them (see section SIV). In contrast to comagnetometers that should operate in a specific near-zero bias field, the spin-based amplifier operates in a broad range of bias fields, leading to the difference in the explored frequency range and sensitivity.…”

“…The resonantly oscillating pseudo-magnetic fields can be generated by modulating the relative speed between the source and 129 Xe amplifier. Combining our current 129 Xe-based amplifier and recently developed SmCo 5 spin sources ( 19 , 20 ), the sensitivity to ∣ f 6+7 ∣<10 −20 ,∣ f 14 ∣<10 −31 ,∣ f 15 ∣<10 −4 ,∣ f 16 ∣<10 −4 can potentially reach into unexplored parameter space for the force range from 0.01 to 100 m, while for ∣ f 8 ∣<10 −23 , this is the case for the force range from 0.01 to 1 m. A further improvement of the experimental sensitivity to spin-dependent interactions can be anticipated by using 3 He noble gas as the spin-based amplifier, which has much longer spin-coherence time and larger gyromagnetic ratio than those of 129 Xe ( 49 ). Using 3 He-K systems, the projected magnetic sensitivity to those spin-dependent interactions can be improved by four orders of magnitude ( 40 ).…”

“…Some of them may break the charge, parity, and time-reversal symmetries or their combinations ( 11 , 37 ); they were introduced to understand the symmetries of charge conjugation and parity in quantum chromodynamics ( 3 ). Many experiments have been performed to search for static spin-dependent interactions ( 12 , 14 – 16 , 20 – 23 , 25 , 26 , 29 , 31 , 32 ), while the velocity-dependent interactions have been studied less extensively ( 18 , 19 , 24 , 28 , 30 ). Following the notation in ( 37 , 38 ), the spin- and velocity-dependent interactions to be studied here are where f 4+5 and f 12+13 are dimensionless coupling constant, c is the speed of light in vacuum, is the spin vector and m is the mass of the polarized fermion, v is the relative velocity between two interacting fermions, is the unit vector in the direction between them, and λ = ħ( m b c ) −1 is the force range (or the boson Compton wavelength) with m b being the light boson mass.…”

Constraints on Theoretical Predictions beyond the Standard Model from the Casimir Effect and Some Other Tabletop Physics

“…which is valid for the boson masses below 1 µeV [109]. Many other laboratory experiments on constraining the hypothetical interactions of different types have been performed which are not directly relevant to the Casimir physics.…”

Limits on axions and axionlike particles within the axion window using a spin-based amplifier

“…Since the first experimental searches for exotic spin-spin interactions [2], recent progress on exploring such interactions over a broad range of particle masses has been enabled by advances in techniques including magnetometry [8,[21][22][23][24], nuclear magnetic resonance [10,20,25,26], torsionpendulum measurements [27,28], trapped ions measurements [29], nitrogen-vacancy centers in diamond [30], geoelectrons [31,32], neutron beams [9], masers [33,34] and cantilevers [35]. The tree-level interactions arising from pseudoscalar boson exchange are spin-dependent [36].…”