Phase-coherent sensing of the center-of-mass motion of trapped-ion crystals

Quantum-enhanced sensing of displacements and electric fields with large trapped-ion crystals

“…With this technique, we achieve a sensitivity of 8.8 ± 0.4 dB below the SQL for displacements and 4.0 ± 0.5 dB below the SQL for electric fields. In practical terms we demonstrate an ultimate electric field measurement sensitivity of 240 ± 10 nV m −1 / √ Hz, an improvement by a factor of 300 over prior off-resonant classical protocols in trapped ions [14,16] and more than an order of magnitude compared to state-of-the-art electrometers based on Rydberg FIG. 1.…”

“…In parallel, mechanical oscillators have become established as exquisite quantum tools to measure small displacements due to weak forces and electric fields [9][10][11][12][13][14][15][16][17], such as those generated by axion-like dark matter and hidden photons [18]. At the simplest level, a weak, resonant force interacting with the mechanical oscillator generates a small coherent displacement β of the oscillator amplitude over time.…”

“…Entanglement-enhanced sensor: Our quantum sensor consists of a single-plane Coulomb crystal of N ∼ 150 9 Be + ions confined in a Penning trap [14,16,[26][27][28], as shown in Fig. 1.…”

Phonon-laser ultrasensitive force sensor

“…With development of nanotechnology using atomic and molecular sensors, the physical quantities have been detected in a higher level of sensitivity than ever before due to the excellent perceived performance of the sensors [1][2][3][4][5][6][7][8]. Force detection has been always taking an important role in precision measurement since all the changes of motion are concerned with the force due to Newton's laws, where the small force detection by trapped ions or atoms has recently demonstrated the superiority of high sensitivity and broad adjustability [9][10][11][12][13][14][15][16]. The weak AC electric force was sensitively detected by means of spin-motion entanglement in two-dimensional trapped-ion mechanical oscillators [9][10][11].…”

“…Force detection has been always taking an important role in precision measurement since all the changes of motion are concerned with the force due to Newton's laws, where the small force detection by trapped ions or atoms has recently demonstrated the superiority of high sensitivity and broad adjustability [9][10][11][12][13][14][15][16]. The weak AC electric force was sensitively detected by means of spin-motion entanglement in two-dimensional trapped-ion mechanical oscillators [9][10][11]. The radio-frequency electric force as small as 5 yN was measured, based on the technique of injection-locked phonon laser, by observing the range of injected frequency and the gravity variance of the ion's displacement [12].…”