| 1. |
- Aybas, Deniz, et al.
(författare)
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Search for Axionlike Dark Matter Using Solid-State Nuclear Magnetic Resonance
- 2021
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 126:14
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Tidskriftsartikel (refereegranskat)abstract
- We report the results of an experimental search for ultralight axionlike dark matter in the mass range 162-166 neV. The detection scheme of our Cosmic Axion Spin Precession Experiment is based on a precision measurement of Pb-207 solid-state nuclear magnetic resonance in a polarized ferroelectric crystal. Axionlike dark matter can exert an oscillating torque on Pb-20(7) nuclear spins via the electric dipole moment coupling g(d) or via the gradient coupling g(aNN). We calibrate the detector and characterize the excitation spectrum and relaxation parameters of the nuclear spin ensemble with pulsed magnetic resonance measurements in a 4.4 T magnetic field. We sweep the magnetic field near this value and search for axionlike dark matter with Compton frequency within a 1 MHz band centered at 39.65 MHz. Our measurements place the upper bounds vertical bar g(d)vertical bar < 9.5 x 10(-4) GeV-2 and vertical bar g(aNN)vertical bar( )< 2.8 x 10(-1) GeV-1 (95% confidence level) in this frequency range. The constraint on g d corresponds to an upper bound of 1.0 x 10(-21) e cm on the amplitude of oscillations of the neutron electric dipole moment and 4.3 x 10(-6) on the amplitude of oscillations of CP-violating theta parameter of quantum chromodynamics. Our results demonstrate the feasibility of using solid-state nuclear magnetic resonance to search for axionlike dark matter in the neV mass range.
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| 2. |
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| 3. |
- Centers, Gary P., et al.
(författare)
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Stochastic fluctuations of bosonic dark matter
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Numerous theories extending beyond the standard model of particle physics predict the existence of bosons that could constitute dark matter. In the standard halo model of galactic dark matter, the velocity distribution of the bosonic dark matter field defines a characteristic coherence time τc. Until recently, laboratory experiments searching for bosonic dark matter fields have been in the regime where the measurement time T significantly exceeds τc, so null results have been interpreted by assuming a bosonic field amplitude Φ0 fixed by the average local dark matter density. Here we show that experiments operating in the T ≪ τc regime do not sample the full distribution of bosonic dark matter field amplitudes and therefore it is incorrect to assume a fixed value of Φ0 when inferring constraints. Instead, in order to interpret laboratory measurements (even in the event of a discovery), it is necessary to account for the stochastic nature of such a virialized ultralight field. The constraints inferred from several previous null experiments searching for ultralight bosonic dark matter were overestimated by factors ranging from 3 to 10 depending on experimental details, model assumptions, and choice of inference framework.
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| 4. |
- Dhungel, Omkar, et al.
(författare)
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Near zero-field microwave-free magnetometry with ensembles of nitrogen-vacancy centers in diamond
- 2024
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 109:22
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Tidskriftsartikel (refereegranskat)abstract
- We study cross -relaxation features near zero magnetic field with ensembles of nitrogen -vacancy (NV) centers in diamond and examine their properties in samples with a range of 0.9-16.0 ppm of NV concentrations. The observed NV -NV cross -relaxation features between differently oriented NV centers in high (>= 0.9 ppm)NV-density samples hold promise for a variety of magnetometry applications where microwave fields (or any bias field) disturb the system under study. We theoretically determine the values of the bias magnetic fields corresponding to cross relaxations between different axes and experimentally validate them. The behavior of zero -field cross -relaxation features as a function of temperature is also investigated.
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| 5. |
- Hu, Wenxiang, et al.
(författare)
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A network of superconducting gravimeters as a detector of matter with feeble nongravitational coupling
- 2020
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 74:6
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Tidskriftsartikel (refereegranskat)abstract
- Hidden matter that interacts only gravitationally would oscillate at characteristic frequencies when trapped inside of Earth. For small oscillations near the center of the Earth, these frequencies are around 300 mu Hz. Additionally, signatures at higher harmonics would appear because of the non-uniformity of Earth's density. In this work, we use data from a global network of gravimeters of the International Geodynamics and Earth Tide Service (IGETS) to look for these hypothetical trapped objects. We find no evidence for such objects with masses on the order of 10(14) kg or greater with an oscillation amplitude of 0.1r(e). It may be possible to improve the sensitivity of the search by several orders of magnitude via better understanding of the terrestrial noise sources and more advanced data analysis.
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| 6. |
- Ivády, Viktor, et al.
(författare)
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Photoluminescence at the ground-state level anticrossing of the nitrogen-vacancy center in diamond: A comprehensive study
- 2021
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 103:3
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Tidskriftsartikel (refereegranskat)abstract
- The nitrogen-vacancy center (NV center) in diamond at magnetic fields corresponding to the ground-state level anticrossing (GSLAC) region gives rise to rich photoluminescence (PL) signals due to the vanishing energy gap between the electron spin states, which enables for a broad variety of environmental couplings to have an effect on the NV centers luminescence. Previous works have addressed several aspects of the GSLAC photoluminescence, however, a comprehensive analysis of the GSLAC signature of NV ensembles in different spin environments at various external fields is missing. Here we employ a combination of experiments and recently developed numerical methods to investigate in detail the effects of transverse electric and magnetic fields, strain, P1 centers, NV centers, and the C-13 nuclear spins on the GSLAC photoluminescence. Our comprehensive analysis provides a solid ground for advancing various microwave-free applications at the GSLAC, including but not limited to magnetometry, spectroscopy, dynamic nuclear polarization (DNP), and nuclear magnetic resonance (NMR) detection. We demonstrate that not only the most abundant (NV)-N-14 center but the (NV)-N-15 can also be utilized in such applications.
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