A self-driven hybrid atomic spin oscillator is demonstrated in theory and experiment with a vapor $\mathrm{Rb}$ - $\mathrm{Xe}$ dual-spin system. The raw signal of $\mathrm{Rb}$ spin oscillation is amplified, phase-shifted, and sent back to drive the $\mathrm{Xe}$ spins coherently. By fine-tuning the driving-field strength and phase, a self-sustaining spin-oscillation signal with zero frequency shift is obtained. The effective coherence time is infinitely prolonged beyond the intrinsic coherence time of $\mathrm{Xe}$ spins, forming a hybrid atomic spin oscillator. Spectral analysis indicates that a frequency resolution of 13.1 nHz is achieved, increasing the detection sensitivity for a magnetic field. Allan-deviation analysis shows that the spin oscillator can operate in continuous-wave mode like a spin maser. The prototype spin oscillator can be easily incorporated into other hybrid spin systems and can increase the detection sensitivity of alkali-metal--noble-gas comagnetometers.A self-driven hybrid atomic spin oscillator is demonstrated in theory and experiment with a vapor $\mathrm{Rb}$-$\mathrm{Xe}$ dual-spin system. The raw signal of $\mathrm{Rb}$ spin oscillation is amplified, phase-shifted, and sent back to drive the $\mathrm{Xe}$ spins coherently. By fine-tuning the driving-field strength and phase, a self-sustaining spin-oscillation signal with zero frequency shift is obtained. The effective coherence time is infinitely prolonged beyond the intrinsic coherence time of $\mathrm{Xe}$ spins, forming a hybrid atomic spin oscillator. Spectral analysis indicates that a frequency resolution of 13.1 nHz is achieved, increasing the detection sensitivity for a magnetic field. Allan-deviation analysis shows that the spin oscillator can operate in continuous-wave mode like a spin maser. The prototype spin oscillator can be easily incorporated into other hybrid spin systems and can increase the detection sensitivity of alkali-metal--noble-gas comagnetometers.

arXiv:2301.12121Physical Review AppliedJul 14, 20233 citations

Remote cooling of spin-ensembles through a spin-mechanical hybrid interface

Yang Wang, Durga Bhaktavatsala Rao Dasari, Jörg Wrachtrup

Abstract We present a protocol for the ground-state cooling of a tripartite hybrid quantum system, in which a macroscopic oscillator acts as a mediator between a single-probe spin and a remote spin ensemble. In the presence of weak dispersive coupling between the spins and the oscillator, cooling of the oscillator and the ensemble spins can be achieved by exploiting the feedback from frequent measurements of the single-probe spin. We explore the parameter regimes necessary to cool the ensemble, the oscillator, or both to their thermal ground states. This novel cooling protocol shows that, even with only weak dispersive coupling, energy transfer-like effects can be obtained by simply manipulating the probe spin. These results not only contribute to the development of a practical solution for cooling/polarizing large spin ensembles but also provide a relatively simple means of tuning the dynamics of a hybrid system. The proposed protocol thus has broader implications for advancing various quantum technology applications, such as macroscopic quantum state generation and remote sensing.Abstract We present a protocol for the ground-state cooling of a tripartite hybrid quantum system, in which a macroscopic oscillator acts as a mediator between a single-probe spin and a remote spin ensemble. In the presence of weak dispersive coupling between the spins and the oscillator, cooling of the oscillator and the ensemble spins can be achieved by exploiting the feedback from frequent measurements of the single-probe spin. We explore the parameter regimes necessary to cool the ensemble, the oscillator, or both to their thermal ground states. This novel cooling protocol shows that, even with only weak dispersive coupling, energy transfer-like effects can be obtained by simply manipulating the probe spin. These results not only contribute to the development of a practical solution for cooling/polarizing large spin ensembles but also provide a relatively simple means of tuning the dynamics of a hybrid system. The proposed protocol thus has broader implications for advancing various quantum technology applications, such as macroscopic quantum state generation and remote sensing.

arXiv:2403.16839npj Quantum InformationFeb 6, 20254 citations

Quantum Spin Systems

Ola Bratteli, Derek W. Robinson

Springer eBooksJan 1, 19970 citations

Quadratic coupling between a classical nanomechanical oscillator and a single spin

Shonali Dhingra

Though the motions of macroscopic objects must ultimately be governed by quantum mechanics, the distinctive features of quantum mechanics can be hidden or washed out by thermal excitations and coupling to the environment. For the work of this thesis, we tried to develop a hybrid system consisting a classical and a quantum component, which can be used to probe the quantum nature of both these components. This hybrid system quadratically coupled a nanomechanical oscillator (NMO) with a single spin in presence of a uniform external magnetic field. The NMO was fabricated out of single-layer graphene, grown using Chemical Vapor Deposition (CVD) and patterned using various lithography and etching techniques. The NMO was driven electrically and detected optically. The NMO's resonant frequencies, and their stabilities were studied. The spin originated from a nitrogen vacancy (NV) center in a diamond nanocrystal which is positioned on the NMO. In presence of an external magnetic field, we show that the NV centers are excellent $\theta^{2}$ sensors. Their sensitivity is shown to increase much faster than linearly with the external magnetic field and diverges as the external field approaches an internally-defined limit. Both these components of the hybrid system get coupled by physical placement of NV-containing diamond nanocrystals on top of NMO undergoing torsional mode of oscillation, in presence of an external magnetic field. The capability of the NV centers to detect the quadratic behavior of the oscillation angle of the NMO with excellent sensitivity, ensures quantum non-demolition (QND) measurement of both components of the hybrid system. This enables a bridge between the quantum and classical worlds for a simple readout of the NV center spin and observation of the discrete states of the NMO. This system could become the building block for a wide range of quantum nanomechanical devices.Though the motions of macroscopic objects must ultimately be governed by quantum mechanics, the distinctive features of quantum mechanics can be hidden or washed out by thermal excitations and coupling to the environment. For the work of this thesis, we tried to develop a hybrid system consisting a classical and a quantum component, which can be used to probe the quantum nature of both these components. This hybrid system quadratically coupled a nanomechanical oscillator (NMO) with a single spin in presence of a uniform external magnetic field. The NMO was fabricated out of single-layer graphene, grown using Chemical Vapor Deposition (CVD) and patterned using various lithography and etching techniques. The NMO was driven electrically and detected optically. The NMO's resonant frequencies, and their stabilities were studied. The spin originated from a nitrogen vacancy (NV) center in a diamond nanocrystal which is positioned on the NMO. In presence of an external magnetic field, we show that the NV centers are excellent $\theta^{2}$ sensors. Their sensitivity is shown to increase much faster than linearly with the external magnetic field and diverges as the external field approaches an internally-defined limit. Both these components of the hybrid system get coupled by physical placement of NV-containing diamond nanocrystals on top of NMO undergoing torsional mode of oscillation, in presence of an external magnetic field. The capability of the NV centers to detect the quadratic behavior of the oscillation angle of the NMO with excellent sensitivity, ensures quantum non-demolition (QND) measurement of both components of the hybrid system. This enables a bridge between the quantum and classical worlds for a simple readout of the NV center spin and observation of the discrete states of the NMO. This system could become the building block for a wide range of quantum nanomechanical devices.

Jun 18, 20150 citations

Spin quantum dynamics in hybrid circuits

Matthieu R. Delbecq

Jun 26, 20200 citations

A self-driven hybrid atomic spin oscillator is demonstrated in theory and experiment with a vapor

\mathrm{Rb}

\mathrm{Xe}

dual-spin system. The raw signal of

\mathrm{Rb}

spin oscillation is amplified, phase-shifted, and sent back to drive the

\mathrm{Xe}

spins coherently. By fine-tuning the driving-field strength and phase, a self-sustaining spin-oscillation signal with zero frequency shift is obtained. The effective coherence time is infinitely prolonged beyond the intrinsic coherence time of

\mathrm{Xe}

spins, forming a hybrid atomic spin oscillator. Spectral analysis indicates that a frequency resolution of 13.1 nHz is achieved, increasing the detection sensitivity for a magnetic field. Allan-deviation analysis shows that the spin oscillator can operate in continuous-wave mode like a spin maser. The prototype spin oscillator can be easily incorporated into other hybrid spin systems and can increase the detection sensitivity of alkali-metal--noble-gas comagnetometers.

\theta^{2}

sensors. Their sensitivity is shown to increase much faster than linearly with the external magnetic field and diverges as the external field approaches an internally-defined limit. Both these components of the hybrid system get coupled by physical placement of NV-containing diamond nanocrystals on top of NMO undergoing torsional mode of oscillation, in presence of an external magnetic field. The capability of the NV centers to detect the quadratic behavior of the oscillation angle of the NMO with excellent sensitivity, ensures quantum non-demolition (QND) measurement of both components of the hybrid system. This enables a bridge between the quantum and classical worlds for a simple readout of the NV center spin and observation of the discrete states of the NMO. This system could become the building block for a wide range of quantum nanomechanical devices.