Detecting the presence of weak magnetic fields using nitrogen-vacancy centers

Abstract

We show how nitrogen-vacancy centers can be used to detect the presence of weak magnetic fields, that is, to find out whether a magnetic field, about which we may not have complete information, is actually present or not. The solution to this problem comes from quantum state discrimination theory. The effect of decoherence is taken into account to optimize the time over which the nitrogen-vacancy center is allowed to interact with the magnetic field before making a measurement. We also find the optimum measurement that should be performed. We then show how multiple measurements reduce the error in detecting the magnetic field. Finally, a major limitation of the measurement process, namely, limited photon detection efficiency, is taken into account. Our proposals should be implementable with current experimental technology.

Detection of weak magnetic fields using nitrogen-vacancy centers with maximum confidence

“…2. A direct comparison with the measurements in [45] and we see an approximate ∼50% decrease in the detection error probability.…”

“…The use of minimum error (ME) discrimination for detecting magnetic fields has already been explored in Ref. [45]. However, such a discrimination technique is limited to only von-Neumann measurements.…”

“…We then find µ = e −i2N γb0/f e −2N 2 γ 2 σ 2 b /f 2 . The com- [37,45,58], the expression of ν can be calculated allowing us to find the number of pulses N that would maximize the confidence of the measurement. The results for the case where f = 1 MHz is given in Figs.…”

Calibration-Free Vector Magnetometry Using Nitrogen-Vacancy Center in Diamond Integrated with Optical Vortex Beam

“…It is widely used in room-temperature magnetic sensing and capable of measuring spins in a single-molecular level. [11][12][13][14][15][16][17][18][19][20][21][22] Reconstructing full information of the magnetic field vector (i.e., including magnitude and orientation) is often crucial in applications such as biological magnetic field sensing and the condensed matter physics. 18,[23][24][25] For single NV center, the basic idea of measuring magnetic field is to detect the frequency shift due to the Zeeman effect by the optically detected magnetic resonance (ODMR) procedure.…”

Improving the estimation of environment parameters via initial probe-environment correlations

“…Quantum probes are small, simple, and easily controllable quantum systems which, prepared in a suitable initial state, are allowed to become correlated with the environment and consequently undergo decoherence. Suitable measurements are subsequently performed on the probe allowing us to infer the properties of the environment, with quantum estimation theory supplying the tools to quantify the precision of our estimates [15][16][17][18][19][20][21][22][23][24]. A key tool is the quantum Fisher information which determines the ultimate precision with which we estimate a given environment parameter.…”