He3−Xe129 Comagnetometery using

Abstract

We describe a 3 He-129 Xe comagnetometer using 87 Rb atoms for noble-gas spin polarization and detection. We use a train of 87 Rb π pulses and σ + /σ − optical pumping to realize a finite-field Rb magnetometer with suppression of spin-exchange relaxation. We suppress frequency shifts from polarized Rb by measuring the 3 He and 129 Xe spin precession frequencies in the dark, while applying π pulses along two directions to depolarize Rb atoms. The plane of the π pulses is rotated to suppress the Bloch-Siegert shifts for the nuclear spins. We measure the ratio of 3 He to 129 Xe spin precession frequencies with sufficient absolute accuracy to resolve the Earth's rotation without changing the orientation of the comagnetometer. A frequency resolution of 7 nHz is achieved after integration for 8 hours without evidence of significant drift.PACS numbers: 32.30. Dx, 06.30.Gv, 39.90.+d Spin comagnetometers first introduced in [1] are used for several types of fundamental physics experiments, such as tests of Lorentz, CP and CPT symmetries [2][3][4][5] and searches for spin-dependent forces [6][7][8][9][10]. They also have practical applications as inertial rotation sensors [11][12][13][14][15][16]. When two different spin ensembles occupy the same volume they experience nearly the same average magnetic field [17]. The ratio of their spin precession frequencies f r = ω He /ω Xe can then be used to measure the inertial rotation rate Ω or a spin coupling beyond the Standard Model b:( 1) where B 0 is the bias field alongẑ and γ He , γ Xe are the gyromagnetic ratios for 3 He and 129 Xe, which are well known [18]. Since I = 1/2 nuclear spins are free from quadrupolar energy shifts [19], f r provides an absolute measure of non-magnetic spin interactions-this is particularly important in searches for spin-gravity coupling [20] (where the interaction is hard to modulate), and for use as a gyroscope.An alkali-metal magnetometer provides a natural way to detect nuclear-spin signals because Rb atoms are already used to polarize the nuclear spins by spin-exchange collisions; these collisions enhance the classical dipolar field from the nuclear magnetization by a factor κ 0 [21], which is about 5 for Rb-3 He [22] and 500 for Rb-Xe [23]. However, the presence of polarized Rb atoms also causes large noble-gas frequency shifts that affect the accuracy of Eq. (1). In the past, these frequency shifts have been avoided in 3 He-129 Xe comagnetometers by detecting a smaller dipolar field outside of an alkali-free cell using an RF coil [24] or a SQUID magnetometer [25].In this Letter we describe a new method for operating the 3 He-129 Xe comagnetometer using 87 Rb readout with high sensitivity and accuracy. We develop a 87 Rb magnetometer that can operate in a finite magnetic field of about 5 mG while suppressing Rb-Rb spin-exchange relaxation to increase the magnetometer sensitivity. It

Chip-scale atomic devices

“…In one implementation, two noble gas species are used and ratios of the precession frequencies determine the rotation rate in a field-independent manner ( 129 Xe/ 131 Xe, 199 Hg/ 201 Hg, 83 Kr/ 129 Xe, and 3 He/ 129 Xe). 60,68,69 One species in effect measures the magnetic field, and this signal can be used to correct the field-induced shifts of the second species.…”

“…Although SERF magnetometry can be used to improve the angle-random walk of spin-precession NMR gyroscopes, current schemes require complex synchronous modulation and probing of the alkali spins. 69 Second, the alkali-noble gas DC comagnetometer can be made largely insensitive to magnetic field gradients, transients, and light shifts while improving the rotation sensitivity bandwidth and dynamical response.…”

Parametric Amplification and Noise Squeezing in Room Temperature Atomic Vapors

“…Here we demonstrate parametric amplification and noise-squeezing in the collective atomic spin system realized by an ensemble of optically-pumped room temperature atoms, which is a widely exploited platform for magnetometry [10], quantum information processing [11], and rotation sensing [12]. We show that by using such parametric squeezing we can enhance the signal-to-noise ratio in a Bell-Bloom magnetometer by up to a factor of 10.…”

Closed-Loop Control of Compensation Point in the K−Rb−21Ne Comagnetometer

“…Atomic comagnetometers, which use at least two spin species to measure magnetic fields in the same space and time, have found a wide range of applications, such as tests of CPT and Lorentz invariance [1][2][3][4], searches for anomalous spin-dependent forces [5][6][7][8], and inertial rotation sensing [9][10][11][12][13]. In all of these applications, the long-term stability of the comagnetometer is essential and often limited by noise and systematic effects associated with the external magnetic fields and magnetization due to spin dipolar interactions [14,15].…”