Noisy atomic magnetometry in real time
arXiv:2103.12025 · doi:10.1088/1367-2630/ac3b71
Abstract
Continuously monitored atomic spin-ensembles allow, in principle, for real-time sensing of external magnetic fields beyond classical limits. Within the linear-Gaussian regime, thanks to the phenomenon of measurement-induced spin-squeezing, they attain a quantum-enhanced scaling of sensitivity both as a function of time, , and the number of atoms involved, . In our work, we rigorously study how such conclusions based on Kalman filtering methods change when inevitable imperfections are taken into account: in the form of collective noise, as well as stochastic fluctuations of the field in time. We prove that even an infinitesimal amount of noise disallows the error to be arbitrarily diminished by simply increasing , and forces it to eventually follow a classical-like behaviour in . However, we also demonstrate that, "thanks" to the presence of noise, in most regimes the model based on a homodyne-like continuous measurement actually achieves the ultimate sensitivity allowed by the decoherence, yielding then the optimal quantum-enhancement. We are able to do so by constructing a noise-induced lower bound on the error that stems from a general method of classically simulating a noisy quantum evolution, during which the stochastic parameter to be estimated -- here, the magnetic field -- is encoded. The method naturally extends to schemes beyond the linear-Gaussian regime, in particular, also to ones involving feedback or active control.
arXiv comment27 pages (+16 appendices), 7(+2) figures. Improved summary and conclusions, one extra appendix
References in corpus (58)
- Quantum sensing
- Quantum-enhanced measurements: beating the standard quantum limit
- Optical Magnetometry
- Quantum metrology with nonclassical states of atomic ensembles
- General framework for estimating the ultimate precision limit in noisy quantum-enhanced metrology
- Quantum spin squeezing
- Quantum metrology from a quantum information science perspective
- Resonant nonlinear magneto-optical effects in atoms
- The elusive Heisenberg limit in quantum enhanced metrology
- A Straightforward Introduction to Continuous Quantum Measurement
- Quantum limits in optical interferometry
- Quantum noise limited and entanglement-assisted magnetometry
- Real-time optimal quantum control of mechanical motion at room temperature
- Magnetic sensitivity beyond the projection noise limit by spin squeezing
- Quantum feedback: theory, experiments, and applications
- Portable magnetometry for detection of biomagnetism in ambient environments
- Deterministic Squeezed States with Joint Measurements and Feedback
- Fundamental Quantum Limit to Waveform Estimation
- Efficient tools for quantum metrology with uncorrelated noise
- Measurements with prediction and retrodiction on the collective spin of 10^{11} atoms beat the standard quantum limit
- How do you know if you ran through a wall?
- Spin squeezing via quantum feedback
- Quantum Kalman Filtering and the Heisenberg Limit in Atomic Magnetometry
- Can a quantum nondemolition measurement improve the sensitivity of an atomic magnetometer?
- High Bandwidth Atomic Magnetometery with Continuous Quantum Non-demolition Measurements
- Quantum Metrological Limits via a Variational Approach
- Generation of a squeezed state of an oscillator by stroboscopic back-action-evading measurement
- Spin squeezing and precision probing with light and samples of atoms in the gaussian approximation
- Continuous Weak Measurement and Nonlinear Dynamics in a Cold Spin Ensemble
- Quantum control and measurement of atomic spins in polarization spectroscopy
- Robust quantum parameter estimation: coherent magnetometry with feedback
- Optimal state estimation for cavity optomechanical systems
- Continuous quantum nondemolition feedback and unconditional atomic spin squeezing
- Global Network of Optical Magnetometers for Exotic (GNOME): Physics Novel scheme for exotic physics searches
- Tensor polarizability and dispersive quantum measurement of multilevel atoms
- Observing and Verifying the Quantum Trajectory of a Mechanical Resonator
- Magnetocardiography on an isolated animal heart with a room-temperature optically pumped magnetometer
- Noisy quantum metrology enhanced by continuous nondemolition measurement
- Quantum-Limited Mirror-Motion Estimation
- Ultimate limits for quantum magnetometry via time-continuous measurements
- Stroboscopic back-action evasion in a dense alkali-metal vapor
- Quantum metrology in the presence of spatially correlated noise: Restoring Heisenberg scaling
- Signal tracking beyond the time resolution of an atomic sensor by Kalman filtering
- Estimation of a classical parameter with gaussian probes: magnetometry with collective atomic spins
- Bell's inequality for conditional probabilities as a test for quantum-like behaviour of mind
- Real-Time Kalman Filter: Cooling of an Optically Levitated Nanoparticle
- Prediction and retrodiction with continuously monitored Gaussian states
- Optimal waveform estimation for classical and quantum systems via time-symmetric smoothing. II. Applications to atomic magnetometry and Hardy's paradox
- Hamiltonian Design in Atom-Light Interactions with Rubidium Ensembles: A Quantum Information Toolbox
- Continuous real-time tracking of a quantum phase below the standard quantum limit
- Entanglement-enhanced radio-frequency field detection and waveform sensing
- Retrodiction beyond the Heisenberg uncertainty relation
- Estimation of fluctuating magnetic fields by an atomic magnetometer
- Spin relaxation and decoherence of two-level systems
- Geometric approach to quantum statistical inference
- Smoothing of Gaussian quantum dynamics for force detection
- Number-unconstrained quantum sensing
- On metric of quantum channel spaces