558 research outputs found
The diamond Nitrogen-Vacancy center as a probe of random fluctuations in a nuclear spin ensemble
New schemes that exploit the unique properties of Nitrogen-Vacancy (NV)
centers in diamond are presently being explored as a platform for
high-resolution magnetic sensing. Here we focus on the ability of a NV center
to monitor an adjacent mesoscopic nuclear spin bath. For this purpose, we
conduct comparative experiments where the NV spin evolves under the influence
of surrounding 13C nuclei or, alternatively, in the presence of asynchronous AC
fields engineered to emulate bath fluctuations. Our study reveals substantial
differences that underscore the limitations of the semi-classical picture when
interpreting and predicting the outcome of experiments designed to probe small
nuclear spin ensembles. In particular, our study elucidates the NV center
response to bath fluctuations under common pulse sequences, and explores a
detection protocol designed to probe time correlations of the nuclear spin bath
dynamics. Further, we show that the presence of macroscopic nuclear spin order
is key to the emergence of semi-classical spin magnetometry.Comment: 30 pages, 4 figure
Magnetometry of random AC magnetic fields using a single Nitrogen-Vacancy center
We report on the use of a single NV center to probe fluctuating AC magnetic
fields. Using engineered currents to induce random changes in the field
amplitude and phase, we show that stochastic fluctuations reduce the NV center
sensitivity and, in general, make the NV response field-dependent. We also
introduce two modalities to determine the field spectral composition, unknown a
priori in a practical application. One strategy capitalizes on the generation
of AC-field-induced coherence 'revivals', while the other approach uses the
time-tagged fluorescence intensity record from successive NV observations to
reconstruct the AC field spectral density. These studies are relevant for
magnetic sensing in scenarios where the field of interest has a non-trivial,
stochastic behavior, such as sensing unpolarized nuclear spin ensembles at low
static magnetic fields.Comment: 11 pages, 3 figure
Existence results for impulsive dynamic inclusions on time scales
In this paper, we investigate the existence of solutions and extremal solutions for a first order impulsive dynamic inclusion on time scales. By using suitable fixed point theorems, we study the case when the right hand side has convex as well as nonconvex values
Understadning Faraid: the Case of University Students
The purpose of the study is threefold (1) to examine the level of faraid awareness among university students, as well as (2)the factors that may influence it, and (3)to investigate whether there is any difference between the various groups of respondents based on gender, education level, age and country of origin. The study uses three main statistical techniques to analyse the data, namely, one sample t-test, MANOVA and multiple regression. The data was gathered by distributing the questionnaire to 150 students of International Islamic University Malaysia. The findings indicate that overall the students have good knowledge about faraid. Nevertheless, the students were found to have a misconception and misunderstanding regarding female share in inheritance in Islam. In addition, the findings show that there is significant education level difference in faraid awareness. Finally, the findings conclude that among the variables initially included in the study, only facilitating conditions is significantly influencing the level of awareness of the university students
METHOD FOR HYPER-POLARIZING NUCLEAR SPNS AT ARBTRARY MAGNETIC FELDS
A method of dynamically polarizing the nuclear spin host of nitrogen-vacancy (NV) centers in diamond is provided. The method uses optical, microwave and radio-frequency pulses to recursively transfer spin polarization from the NV electronic spin. Nitrogen nuclear spin initialization approaching 80% at room temperature is demonstrated both in ensemble and single NV centers without relying on level anti-crossings. This makes the method applicable at arbitrary magnetic fields
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