Competition between electric field and magnetic field noise in the decoherence of a single spin in diamond

Abstract

We analyze the impact of electric field and magnetic field fluctuations in the decoherence of the electronic spin associated with a single nitrogen-vacancy (NV) defect in diamond by engineering spin eigenstates protected either against magnetic noise or against electric noise. The competition between these noise sources is analyzed quantitatively by changing their relative strength through modifications of the environment. This study provides significant insights into the decoherence of the NV electronic spin, which is valuable for quantum metrology and sensing applications.Improving the coherence time of solid-state spin qubits is a central challenge in quantum technologies. Decoherence is induced by fluctuations of the local environment and can be mitigated by following several strategies. On one hand, the tools of material science can be exploited to engineer host samples with quantum grade purity 1 . As an example, millisecond-long coherence times have been achieved for electron spin impurities in isotopically purified diamond samples at room temperature 1,2 , while few seconds can be obtained in purified silicon at low temperature 3 . On the other hand, the coherence time can be improved through active quantum control of the many-body environment 4-7 or by decoupling the central spin from its fluctuations, either by applying periodic spin flips 8-10 or by engineering spin eigenstates which are protected against environmental noise [11][12][13][14] . However, for these strategies to be effective, it is crucial to first identify the sources of noise and understand precisely their impact on the coherence properties of the central spin.Here we analyze how magnetic and electric field fluctuations impair the quantum coherence of the electronic spin associated with a single nitrogen-vacancy (NV) defect in diamond. This atomic-sized defect is attracting considerable interest for a broad range of applications including quantum metrology and sensing 15-17 , quantum information processing 18 and hybrid quantum systems [19][20][21] . For all these applications, optimal performances require a long spin coherence time. In this work, we analyze the contributions of magnetic and electric field fluctuations to spin decoherence by exploiting spin eigenstates protected either against magnetic noise or against electric noise 22 . The competition between these noise sources is then analyzed quantitatively by changing their relative strength through modifications of the NV defect environment.The NV defect in diamond has a spin triplet ground state S = 1 with a zero-field splitting D ≈ 2.88 GHz between the m s = 0 and m s = ±1 spin sublevels, where m s denotes the spin projection along the NV symmetry axis (z). The spin Hamiltonian describing the ground state in the presence of strain, electric field E and magnetic field B has been discussed in detail in Refs. [22,23]. The strain, which is induced by a local deformation of the diamond crystal, can be treated as a local static electric field Σ interacting with the NV defect throug...

Storing quantum information in spins and high-sensitivity ESR

“…These transitions are characterised by their value of df /dB (the first order dependence of the transition frequency, f , with applied magnetic field B, equal to gµ B /h for a free electron where g is the electron g-factor, µ B the Bohr magneton, and h Planck's constant), which approaches zero at so-called 'clock' or 'ZE-FOZ' (zero first-order Zeeman) transitions [9]. Such transitions are evidently absent for simple S = 1/2 systems, but can result from the interplay of various spin Hamiltonian terms found in higher-spin systems or systems with strongly coupled electron and nuclear spins [9,12,[22][23][24].…”

Electron spin resonance from NV centers in diamonds levitating in an ion trap

“…Our results furthermore show angular stability of the charged diamonds over time scales of minutes, a necessary step towards spin-controlled levitating particles. Ramsey spectroscopy or electric field noise measurements [27] will then be implemented to assess the applicability of nanodiamonds containing NV − centers in ion traps for quantum sensing. This system can for instance be a potentially useful tool for vectorial magnetometry, and enable the observation of quantum geometric phases [28] and be used as high precision multi-axis rotational sensor [28,29].…”

NV−–N+ pair centre in 1b diamond

“…Their observations are consistent with present measurements. Related to these effects Jamonneau et al [63] reported electric field fluctuation that contributed to the noise in the measurement of spin coherence of NV − in single spin systems. In a very different experiment Bradac et al [64] and Inam et al [65] have investigated very small nano-diamonds.…”