Journal articles on the topic 'Dipole trapping'

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1

Al-Marzoug, S. M. "Scattering of a discrete soliton by impurity in dipolar Bose–Einstein condensates." International Journal of Modern Physics B 28, no. 30 (December 4, 2014): 1450214. http://dx.doi.org/10.1142/s0217979214502142.

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Scattering of a discrete soliton by a single impurity in dipolar Bose–Einstein condensate is investigated numerically. The results show that the increase of the strength of dipolar interactions leads to repeated reflection, transmission and trapping regions due to energy exchange between the center of mass motion and the internal modes of the impurity. However, increasing the strength of the attractive nonlocal dipole–dipole interaction will result in different scattering windows. While the dipole–dipole interaction can significantly expand the trapping region of the system, nevertheless transmission resonances through the impurity are still observed.
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2

Webster, S. A., G. Hechenblaikner, S. A. Hopkins, J. Arlt, and C. J. Foot. "Dipole force trapping of caesium atoms." Journal of Physics B: Atomic, Molecular and Optical Physics 33, no. 19 (September 15, 2000): 4149–55. http://dx.doi.org/10.1088/0953-4075/33/19/323.

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3

Williams, J. F., J. B. Wang, and C. J. Carter. "A Monte Carlo Study of Radiation Trapping Effects." Australian Journal of Physics 50, no. 3 (1997): 645. http://dx.doi.org/10.1071/p96099.

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A Monte Carlo simulation of radiative transfer in an atomic beam is carried out to investigate the effects of radiation trapping on electron–atom collision experiments. The collisionally excited atom is represented by a simple electric dipole, for which the emission intensity distribution is well known. The spatial distribution, frequency and free path of this and the sequential dipoles were determined by a computer random generator according to the probabilities given by quantum theory. By altering the atomic number density at the target site, the pressure dependence of the observed atomic lifetime, the angular intensity distribution and polarisation of the radiation field is studied.
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4

Sripakdee, Chatchawal. "The Investigation of WGM Effective Potential from Micro PANDA Ring Resonator." Applied Mechanics and Materials 866 (June 2017): 337–40. http://dx.doi.org/10.4028/www.scientific.net/amm.866.337.

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In this work, the whispering gallery mode effective potential generated by micro PANDA ring resonator for a two level system of atom – electric field coupling is investigated and presented. The depth of trapping potential is proportional to electric intensity and damping rate of transition of dipole polarization. The trial harmonics potential well is established by using dipole potential under ac Stark effect. The optimum intensity and lifetime for each WGM trapping wavelengths under the effect of thermal noise is reported.
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5

Goldstein, E., P. Pax, K. J. Schernthanner, B. Taylor, and P. Meystre. "Influence of the dipole-dipole interaction on velocity-selective coherent population trapping." Applied Physics B Laser and Optics 60, no. 2-3 (1995): 161–67. http://dx.doi.org/10.1007/bf01135858.

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6

DAVYDOVA, T. A., and V. M. LASHKIN. "Drift-wave trapping by drift vortices." Journal of Plasma Physics 58, no. 1 (July 1997): 11–18. http://dx.doi.org/10.1017/s002237789700562x.

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The possibility for a drift dipole vortex to trap free drift waves is demonstrated. Drift perturbations can be trapped near the centre of the vortex or at its sides. The localization domain and eigenfrequencies of trapped modes are obtained.
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7

Hu, Fang-Qi, and Ju-Kui Xue. "Breathing dynamics of a trapped impurity in a dipolar Bose gas." Modern Physics Letters B 28, no. 22 (August 30, 2014): 1450185. http://dx.doi.org/10.1142/s0217984914501851.

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With the consideration of impurity-bosons coupling and dipole–dipole interactions (DDI), we study the breathing dynamics of a harmonically trapped impurity interacting with a separately trapped background of dipolar Bose gas. By using the variational approach, the breathing equations, the breathing frequencies and the effective potentials governing the breathing dynamics of the impurity in dipolar gas are obtained. The effects of DDI, impurity-bosons interaction and external trapping potentials on breathing dynamics of impurity are discussed. We find that, because of the anisotropic and long-range characters of DDI, the effects of DDI, impurity-bosons interaction and external trapping potentials on breathing dynamics of impurity are strongly coupled. DDI has significant modification on dynamics, which depends on the external trapping potentials. For spherically symmetric external trapping, DDI makes the impurity more cigar-shaped along axial direction and the breathing oscillation in radial direction is suppressed by DDI. However, the effect of DDI on the breathing dynamics is weakened for cigar-shaped external trapping. Interestingly, for strong external pancake-shaped trapping, the symmetries of the breathing dynamics with respect to attractive and repulsive impurity-bosons coupling recover. Especially, for some critical value of impurity-bosons coupling, the breathing dynamics undergo a sudden quench.
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8

Dubau-Assibat, Nathalie, Antoine Baceiredo, and Guy Bertrand. "Lawesson's Reagent: An Efficient 1,3-Dipole Trapping Agent." Journal of Organic Chemistry 60, no. 12 (June 1995): 3904–6. http://dx.doi.org/10.1021/jo00117a050.

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9

Aldossary, O. M. "Bottle atom trapping configuration by optical dipole forces." Journal of King Saud University - Science 26, no. 1 (January 2014): 29–35. http://dx.doi.org/10.1016/j.jksus.2013.08.002.

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10

Lee, Jong-Hoon, Junghwan Kim, Geunjin Kim, Dongguen Shin, Song Yi Jeong, Jinho Lee, Soonil Hong, et al. "Introducing paired electric dipole layers for efficient and reproducible perovskite solar cells." Energy & Environmental Science 11, no. 7 (2018): 1742–51. http://dx.doi.org/10.1039/c8ee00162f.

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11

Mei, D. M., R. Panth, K. Kooi, H. Mei, S. Bhattarai, M. Raut, P. Acharya, and G. J. Wang. "Evidence of cluster dipole states in germanium detectors operating at temperatures below 10 K." AIP Advances 12, no. 6 (June 1, 2022): 065113. http://dx.doi.org/10.1063/5.0094194.

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By studying charge trapping in germanium detectors operating at temperatures below 10 K, we demonstrate for the first time that the formation of cluster dipole states from residual impurities is responsible for charge trapping. Two planar detectors with different impurity levels and types are used in this study. When drifting the localized charge carriers created by α particles from the top surface across a detector at a lower bias voltage, significant charge trapping is observed when compared to operating at a higher bias voltage. The amount of charge trapping shows a strong dependence on the type of charge carriers. Electrons are trapped more than holes in a p-type detector, while holes are trapped more than electrons in an n-type detector. When both electrons and holes are drifted simultaneously using the widespread charge carriers created by γ rays inside the detector, the amount of charge trapping shows no dependence on the polarity of bias voltage.
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12

Yang, Yonghao, Zhigang Li, Chunhui Wu, Wen Li, Jin Wang, Mingdong Yi, and Wei Huang. "Nanostructured interfacial dipole layers for high-performance and highly stable nonvolatile organic field-effect transistor memory." Journal of Materials Chemistry C 10, no. 9 (2022): 3292–99. http://dx.doi.org/10.1039/d1tc05927k.

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13

Liu, Bing Hui, Li Jun Yan, and Yang Wang. "Calculation of Maxwell Stress Tensor Using 3D FDTD for Trapping Force in Near-Field Optical Tweezers." Materials Science Forum 697-698 (September 2011): 590–95. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.590.

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New forms of trapping force are proposed for the design of near-field optical tweezers. Without the limitation of dipole approximation, the trapping force acting on a nano-particle located in near-field region can be solved by direct calculation of Maxwell stress tensor using 3D FDTD method. The new forms are used to design near-field optical trapping with a metal-coated fiber probe. Calculations show that the fiber probe can trap a nano-particle with tens of nanometres diameter to different positions with different distance from the probe tip. In order to achieve higher trapping capability, the feasibility of near-field trapping near the optical fiber probe after adding the AFM metallic probe is shown by analyzing trapping forces along three axis directions. The correctness of new forms is demonstrated by numerical results.
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14

Beck, Fiona J., Sudha Mokkapati, and Kylie R. Catchpole. "Light trapping with plasmonic particles: beyond the dipole model." Optics Express 19, no. 25 (November 23, 2011): 25230. http://dx.doi.org/10.1364/oe.19.025230.

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15

Dil, H., J. Lobo-Checa, R. Laskowski, P. Blaha, S. Berner, J. Osterwalder, and T. Greber. "Surface Trapping of Atoms and Molecules with Dipole Rings." Science 319, no. 5871 (March 28, 2008): 1824–26. http://dx.doi.org/10.1126/science.1154179.

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16

Maron, Gabriele, Xinxin Hu, Luke Masters, Lucas Pache, Michael Scheucher, Elisa Will, Jürgen Volz, and Arno Rauschenbeutel. "Trapping a single atom in the evanescent field of a WGM-resonator." EPJ Web of Conferences 266 (2022): 11007. http://dx.doi.org/10.1051/epjconf/202226611007.

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We demonstrate the trapping of single atoms in the evanescent field of a whispering-gallery-mode (WGM) resonator with a standing wave optical dipole trap. We present our progress towards an improved trap loading scheme.
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17

Rancourt, D. G., G. Lamarche, P. Tume, A. E. Lalonde, P. Biensan, and S. Flandrois. "Dipole–dipole interactions as the source of spin-glass behaviour in exchangewise two-dimensional ferromagnetic layer compounds." Canadian Journal of Physics 68, no. 10 (October 1, 1990): 1134–37. http://dx.doi.org/10.1139/p90-160.

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We have studied magnetic layered materials that have in-plane ferromagnetic exchange interactions, and dipole–dipole only interplane interactions. These are biotite mica (including a nearly ideal annite end member) and new graphite bi-intercalation compounds that contain regularly stacked arrays of ferromagnetic and diamagnetic intercalates. All these strictly (exchangewise) two-dimensional materials exhibit hysteretic spin-glass magnetization cusps at temperatures up to 42 K. This proves that, in the presence of ferromagnetic correlations, classical dipole–dipole forces can play an important role in causing spin-glass behaviour at elevated temperatures. The layered materials described are ideal model systems for the study of a class of spin glasses that require only ferromagnetic exchange interactions. Below some characteristic temperature TFC, the latter interactions induce ferromagnetic correlations that give rise to significant dipole–dipole coupling leading to "domain configuration trapping" and an onset of temperature hysteresis at T ~ TFC.
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18

Ibrahim, Siti Noorjannah, and Maan M. Alkaisi. "Microelectrode Design for Particle Trapping on Bioanalysis Platform." Advanced Materials Research 1115 (July 2015): 543–48. http://dx.doi.org/10.4028/www.scientific.net/amr.1115.543.

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Microelectrode geometry has significant influence on particles trapping techniques used on bioanalysis platforms. In this paper, the particle trapping patterns of dipole, quadrupole and octupole microelectrode using dielectrophoretic force (DEP) are discussed. The microelectrodes were constructed on a metal-insulator-metal platform, built on a silicon nitride (Si3N4) coated silicon substrate. The back contact is made from 20 nm nickel-chromium (NiCr) and 100 nm gold (Au) as the first layer. Then, SU-8-2005 (negative photoresist) is used on the second layer to create microcavities for trapping the particles. The third layer, where the three geometries were patterned, is made from 20 nm NiCr and 100 nm Au layers. Prior to fabrication, the particles trapping patterns of the microelectrodes were profiled using a finite element software, COMSOL 3.5a. Trapping patterns for the three geometries were evaluated using polystyrene latex microbeads. Results from the experiment validate simulation studies in term of microelectrode trapping ability up to single particle efficiency. It provides the potential of converting the trapping platform into a lab-on-chip system.
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19

Hotter, Christoph, David Plankensteiner, Laurin Ostermann, and Helmut Ritsch. "Superradiant cooling, trapping, and lasing of dipole-interacting clock atoms." Optics Express 27, no. 22 (October 14, 2019): 31193. http://dx.doi.org/10.1364/oe.27.031193.

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20

Beaufils, Q., R. Chicireanu, A. Pouderous, B. Laburthe-Tolra, E. Maréchal, L. Vernac, J. C. Keller, and O. Gorceix. "Trapping metastable chromium atoms in a crossed optical dipole trap." Annales de Physique 32, no. 2-3 (2007): 171–73. http://dx.doi.org/10.1051/anphys:2008035.

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21

Guo, Jingkun, Zijin Lei, Fan Wang, Jingjing Xu, and Shengyong Xu. "Some Energy Issues for a Nanoscale Electrostatic Potential Well in Saline Solutions." Chemosensors 8, no. 3 (July 2, 2020): 50. http://dx.doi.org/10.3390/chemosensors8030050.

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An electrostatic potential well may be applied to trap and manipulate charged micro- and nanoparticles. An electrostatic potential well obtained from a certain charge distribution may be used to mimic the electrostatic interactions among biomolecules in live biosystems. In this study, we present a simulation study on the trapping performance of dipole clusters, which are arranged in 10 nm-sized, pentagon-shaped structures in a saline solution. The influence of electrostatic energy, entropy, and van der Waals interaction on the trapping performance of these nanostructures is then systematically calculated. The results show that the electrostatic potential well system demonstrated a moderate trapping capability, which could be enhanced using van der Waals interactions. The entropy significantly contributes to the trapping capability. This study offers some ideas for developing practical biomimetic electrostatic tweezers and nanorobots working in an ionic solution.
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22

Lavrukhin, Alexander S., Igor I. Alexeev, and Ilya V. Tyutin. "Influence of the Earth's ring current strength on Størmer's allowed and forbidden regions of charged particle motion." Annales Geophysicae 37, no. 4 (July 9, 2019): 535–47. http://dx.doi.org/10.5194/angeo-37-535-2019.

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Abstract. Størmer's particles' trapping regions for a planet with an intrinsic dipolar magnetic field are considered, taking into account the ring current which arises due to the trapped particles' drift for the case of the Earth. The influence of the ring current on the particle trapping regions' topology is investigated. It is shown that a critical strength of the ring current exists under which further expansion of the trapping region is no longer possible. Before reaching this limit, the dipole field, although deformed, retains two separated Størmer regions. After transition of critical magnitude, the trapping region opens up, and charged particles, which form the ring current, get the opportunity to leave it, thus decreasing the ring current strength. Numerical calculations have been performed for protons with typical energies of the Earth's radiation belt and ring current. For the Earth's case, the Dst index for the critical ring current strength is calculated.
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23

Lovera, Andrea, and Olivier J. F. Martin. "Plasmonic trapping with realistic dipole nanoantennas: Analysis of the detection limit." Applied Physics Letters 99, no. 15 (October 10, 2011): 151104. http://dx.doi.org/10.1063/1.3650267.

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24

Zhang, Weihua, Lina Huang, Christian Santschi, and Olivier J. F. Martin. "Trapping and Sensing 10 nm Metal Nanoparticles Using Plasmonic Dipole Antennas." Nano Letters 10, no. 3 (March 10, 2010): 1006–11. http://dx.doi.org/10.1021/nl904168f.

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25

Vinogradov, V. A., K. A. Karpov, S. S. Lukashov, and A. V. Turlapov. "Trapping of lithium atoms in a large hollow optical dipole trap." Quantum Electronics 50, no. 6 (June 11, 2020): 520–24. http://dx.doi.org/10.1070/qel17362.

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26

Zabolotskiı̆, A. A. "Exciton Self-Trapping in Molecular Media with an Elastic Dipole Moment." Optics and Spectroscopy 99, no. 5 (2005): 695. http://dx.doi.org/10.1134/1.2135844.

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27

Peng, Jin-sheng, and Gao-xiang Li. "Effects of the dipole-dipole interaction on dynamic properties and atomic coherent trapping of a two-atom system." Physical Review A 47, no. 5 (May 1, 1993): 4212–18. http://dx.doi.org/10.1103/physreva.47.4212.

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28

Wang, Yu-Fu, Min-Ruei Tsai, Po-Yang Wang, Chin-Yang Lin, Horng-Long Cheng, Fu-Ching Tang, Steve Lien-Chung Hsu, Chih-Chun Hsu, and Wei-Yang Chou. "Controlling carrier trapping and relaxation with a dipole field in an organic field-effect device." RSC Advances 6, no. 81 (2016): 77735–44. http://dx.doi.org/10.1039/c6ra09676j.

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29

OLDHAM, TIMOTHY R. "SWITCHING OXIDE TRAPS." International Journal of High Speed Electronics and Systems 14, no. 02 (June 2004): 581–603. http://dx.doi.org/10.1142/s0129156404002533.

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Positive oxide trapped charge is one of the main factors determining the radiation response of a CMOS device. The most widely accepted model for oxide-trapped charge is the dipole model, originally proposed by Lelis et al. The annealing of radiation-induced positive trapped charge proceeds (usually) via the tunneling of electrons, which form metastable dipoles, compensating the trapped positive charge without removing it. Under appropriate bias, these compensating electrons can tunnel back to the Si substrate, restoring the trapped positive charge. The experimental work leading to the development of this model is summarized. By now there is a large body of experimental and theoretical work by others, confirming and extending the original model. In particular, the relevance of the model to some electron trapping studies has been shown, and its application to the larger topic of oxide reliability is discussed.
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30

Nakamura, K., S. Nagase, T. Nakashita, T. Hayamizu, T. Aoki, H. Nagahama, N. Ozawa, et al. "Development of a Laser Frequency Stabilization and an Optical Transmission System for the Francium Electric Dipole Moment Search." Journal of Physics: Conference Series 2249, no. 1 (April 1, 2022): 012010. http://dx.doi.org/10.1088/1742-6596/2249/1/012010.

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Abstract We developed a laser frequency stabilization and an optical fiber transmission system for the the francium electric dipole moment search. The absolute accuracy of a laser frequency stabilization scheme using a state-of-the-art commercial wavelength meter was 0.48 MHz at ±2 nm and -1.33 MHz at ±200 nm from calibration wavelength, respectively, and the frequency instability is below 10-9 with a standard deviation of 0.56 MHz over 60 hours. We also demonstrated that a 400 m long fiber laid between laboratories can transmit 30 mW of trapping laser light, which is sufficient for a magneto-optical trapping of francium. The polarization crosstalk in the fiber was stable at -25 dB over 12 hours of measurement.
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31

Karpa, Leon. "Interactions of Ions and Ultracold Neutral Atom Ensembles in Composite Optical Dipole Traps: Developments and Perspectives." Atoms 9, no. 3 (July 4, 2021): 39. http://dx.doi.org/10.3390/atoms9030039.

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Ion–atom interactions are a comparatively recent field of research that has drawn considerable attention due to its applications in areas including quantum chemistry and quantum simulations. In first experiments, atomic ions and neutral atoms have been successfully overlapped by devising hybrid apparatuses combining established trapping methods, Paul traps for ions and optical or magneto-optical traps for neutral atoms, respectively. Since then, the field has seen considerable progress, but the inherent presence of radiofrequency (rf) fields in such hybrid traps was found to have a limiting impact on the achievable collision energies. Recently, it was shown that suitable combinations of optical dipole traps (ODTs) can be used for trapping both atoms and atomic ions alike, allowing to carry out experiments in absence of any rf fields. Here, we show that the expected cooling in such bichromatic traps is highly sensitive to relative position fluctuations between the two optical trapping beams, suggesting that this is the dominant mechanism limiting the currently observed cooling performance. We discuss strategies for mitigating these effects by using optimized setups featuring adapted ODT configurations. This includes proposed schemes that may mitigate three-body losses expected at very low temperatures, allowing to access the quantum dominated regime of interaction.
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32

Saakyan, S. A., V. A. Sautenkov, N. V. Morozov, A. A. Bobrov, and B. B. Zelener. "Increasing the trapping lifetime of lithium-7 atoms in optical dipole trap." Journal of Physics: Conference Series 1787, no. 1 (February 1, 2021): 012046. http://dx.doi.org/10.1088/1742-6596/1787/1/012046.

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33

Li, Ai-Xian, Su-Qing Duan, and Wei Zhang. "Nuclear spin cooling by electric dipole spin resonance and coherent population trapping." Physica E: Low-dimensional Systems and Nanostructures 93 (September 2017): 105–10. http://dx.doi.org/10.1016/j.physe.2017.06.001.

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34

Khan, Noor Saeed, Auwalu Hamisu Usman, Arif Sohail, Abid Hussanan, Qayyum Shah, Naeem Ullah, Poom Kumam, Phatiphat Thounthong, and Usa Wannasingha Humphries. "A Framework for the Magnetic Dipole Effect on the Thixotropic Nanofluid Flow Past a Continuous Curved Stretched Surface." Crystals 11, no. 6 (June 7, 2021): 645. http://dx.doi.org/10.3390/cryst11060645.

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The magnetic dipole effect for thixotropic nanofluid with heat and mass transfer, as well as microorganism concentration past a curved stretching surface, is discussed. The flow is in a porous medium, which describes the Darcy–Forchheimer model. Through similarity transformations, the governing equations of the problem are transformed into non-linear ordinary differential equations, which are then processed using an efficient and powerful method known as the homotopy analysis method. All the embedded parameters are considered when analyzing the problem through solution. The dipole and porosity effects reduce the velocity, while the thixotropic nanofluid parameter increases the velocity. Through the dipole and radiation effects, the temperature is enhanced. The nanoparticles concentration increases as the Biot number and curvature, solutal, chemical reaction parameters increase, while it decreases with increasing Schmidt number. The microorganism motile density decreases as the Peclet and Lewis numbers increase. Streamlines demonstrate that the trapping on the curved stretched surface is uniform.
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35

Singh, Sukhjit, Jyoti, Bindiya Arora, B. K. Sahoo, and Yan-mei Yu. "Magic Wavelengths for Optical-Lattice Based Cs and Rb Active Clocks." Atoms 8, no. 4 (November 10, 2020): 79. http://dx.doi.org/10.3390/atoms8040079.

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Active clocks could provide better stabilities during initial stages of measurements over passive clocks, in which stabilities become saturated only after long-term measurements. This unique feature of an active clock has led to search for suitable candidates to construct such clocks. The other challenging task of an atomic clock is to reduce its possible systematics. A major part of the optical lattice atomic clocks based on neutral atoms are reduced by trapping atoms at the magic wavelengths of the optical lattice lasers. Keeping this in mind, we find the magic wavelengths between all possible hyperfine levels of the transitions in Rb and Cs atoms that were earlier considered to be suitable for making optical active clocks. To validate the results, we give the static dipole polarizabilities of Rb and Cs atoms using the electric dipole transition amplitudes that are used to evaluate the dynamic dipole polarizabilities and compare them with the available literature values.
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36

Bromley, Benjamin C., and Scott J. Kenyon. "Magnetic Interactions in Orbital Dynamics." Astronomical Journal 164, no. 6 (November 1, 2022): 229. http://dx.doi.org/10.3847/1538-3881/ac9301.

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Abstract The magnetic field of a host star can impact the orbit of a stellar partner, planet, or asteroid if the orbiting body is itself magnetic or electrically conducting. Here, we focus on the instantaneous magnetic forces on an orbiting body in the limit where the dipole approximation describes its magnetic properties as well as those of its stellar host. A permanent magnet in orbit about a star will be inexorably drawn toward the stellar host if the magnetic force is comparable to gravity due to the steep radial dependence of the dipole–dipole interaction. While magnetic fields in observed systems are much too weak to drive a merger event, we confirm that they may be high enough in some close compact binaries to cause measurable orbital precession. When the orbiting body is a conductor, the stellar field induces a time-varying magnetic dipole moment that leads to the possibility of eccentricity pumping and resonance trapping. The challenge is that the orbiter must be close to the stellar host, so that magnetic interactions must compete with tidal forces and the effects of intense stellar radiation.
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37

Zheng, Ningxuan, Wenliang Liu, Jizhou Wu, Yuqing Li, Vladimir Sovkov, and Jie Ma. "Parametric Excitation of Ultracold Sodium Atoms in an Optical Dipole Trap." Photonics 9, no. 7 (June 22, 2022): 442. http://dx.doi.org/10.3390/photonics9070442.

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Parametric modulation is an effective tool to measure the trap frequency and investigate the atom dynamics in an optical dipole trap or lattices. Herein, we report on experimental research of parametric resonances in an optical dipole trap. By modulating the trapping potential, we have measured the atomic loss dependence on the frequency of the parametric modulations. The resonance loss spectra and the evolution of atom populations at the resonant frequency have been demonstrated and compared under three modulation waveforms (sine, triangle and square waves). A phenomenological theoretical simulation has been performed and shown good accordance with the observed resonance loss spectra and the evolution of atom populations. The theoretical analysis can be easily extended to a complex waveform modulation and reproduce enough of the experiments.
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38

Sun, Chuang, and Jize Yan. "A hybrid method to calculate optical torque: Application to a nano-dumbbell trapped by a metalens." AIP Advances 12, no. 7 (July 1, 2022): 075024. http://dx.doi.org/10.1063/5.0094665.

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The hyper-fast rotation frequency realized in an optical levitation system provides an essential platform for various applications. Benefiting from the development of integrated photonics, optically trapping and manipulating a micro-particle via a metalens has been a significant development trend. The metalens’ powerful and flexible controlling ability of the optical field opens the door to tailoring optical trapping potential. However, the existing methods are difficult to compute optical forces and torques on a non-spherical particle trapped by a metalens-based trapping system, especially when the trapping potential is tailored by a delicately designed metalens. Therefore, a hybrid method by combining the finite difference in time-domain and discrete dipole approximation method is proposed in this paper to realize this goal. The relative error of this method is verified to be below 10%. Based on this hybrid method, the fractional vortex field is found in a metalens-based trapping system for the first time. Then, the optical torque’s dependency on a nano-dumbbell’s geometrical parameters and spatial orientation angles are studied. It is found that there is a torque driving the nano-dumbbell to rotate about the optical axis, and the long axis of the nano-dumbbell tends to be aligned to the polarization plane because of the transverse optical torques if the long axis of the nano-dumbbell is not aligned to the optical axis.
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39

Wang, Zheng Ling, Ming Zhou, Wei Zhang, Chuan Yu Gao, and Guo Rong Cao. "Nanoscale Trap for Isolated Cold Atoms by the Nanoscale Solid-State System." Advanced Materials Research 304 (July 2011): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amr.304.263.

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We propose a novel scheme to generate nanoscale optical trap for cold atoms near the tapered Ag nanotip, in which we take a microdisk cavity near the nanoscale trap and form a nanoscale solid-state system to realize the loading of the isolated cold atoms. We calculate the field distribution by the FDTD method near the nanotip, and discuss the intensity, the optical potential and van der Waals potential as well as the dipole force for 87Rb atoms. We find that the total potential and dipole force can form an attracting nanoscale trap for cold atoms with red-detuned field and it can realize the effective trapping and manipulation of the isolated atoms, which can enable efficient fluorescence photon collection and strong coupling in the coupled optical fiber.
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40

Lembessis, Vassilios E., and Demosthenes Ellinas. "Optical dipole trapping beyond the rotating wave approximation: the case of large detuning." Journal of Optics B: Quantum and Semiclassical Optics 7, no. 11 (September 30, 2005): 319–22. http://dx.doi.org/10.1088/1464-4266/7/11/002.

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41

Nikolaev, I. N., L. N. Kalinina, and A. V. Litvinov. "A new type of trapping center for molecules with dipole moments in insulators." Physics of the Solid State 51, no. 6 (June 2009): 1124–27. http://dx.doi.org/10.1134/s1063783409060067.

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42

Gavriil, Vassilios, Margarita Chatzichristidi, Zoe Kollia, Alkiviadis-Constantinos Cefalas, Nikolaos Spyropoulos-Antonakakis, Vadim Semashko, and Evangelia Sarantopoulou. "Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities." Entropy 20, no. 8 (July 24, 2018): 545. http://dx.doi.org/10.3390/e20080545.

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In thin polymeric layers, external molecular analytes may well be confined within tiny surface nano/microcavities, or they may be attached to ligand adhesion binding sites via electrical dipole forces. Even though molecular trapping is followed by a variation of the entropic potential, the experimental evidence of entropic energy variation from molecular confinement is scarce because tiny thermodynamic energy density diverseness can be tracked only by sub-nm surface strain. Here, it is shown that water confinement within photon-induced nanocavities in Poly (2-hydroxyethyl methacrylate), (PHEMA) layers could be trailed by an entropic potential variation that competes with a thermodynamic potential from electric dipole attachment of molecular adsorbates in polymeric ligands. The nano/microcavities and the ligands were fabricated on a PHEMA matrix by vacuum ultraviolet laser photons at 157 nm. The entropic energy variation during confinement of water analytes on the photon processed PHEMA layer was monitored via sub-nm surface strain by applying white light reflectance spectroscopy, nanoindentation, contact angle measurements, Atomic Force Microscopy (AFM) imaging, and surface and fractal analysis. The methodology has the potency to identify entropic energy density variations less than 1 pJm−3 and to monitor dipole and entropic fields on biosurfaces.
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43

KEVREKIDIS, P. G., R. CARRETERO-GONZÁLEZ, D. J. FRANTZESKAKIS, and I. G. KEVREKIDIS. "VORTICES IN BOSE–EINSTEIN CONDENSATES: SOME RECENT DEVELOPMENTS." Modern Physics Letters B 18, no. 30 (December 30, 2004): 1481–505. http://dx.doi.org/10.1142/s0217984904007967.

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In this brief review we summarize a number of recent developments in the study of vortices in Bose–Einstein condensates, a topic of considerable theoretical and experimental interest in the past few years. We examine the generation of vortices by means of phase imprinting, as well as via dynamical instabilities. Their stability is subsequently examined in the presence of purely magnetic trapping, and in the combined presence of magnetic and optical trapping. We then study pairs of vortices and their interactions, illustrating a reduced description in terms of ordinary differential equations for the vortex centers. In the realm of two vortices we also consider the existence of stable dipole clusters for two-component condensates. Last but not least, we discuss mesoscopic patterns formed by vortices, the so-called vortex lattices and analyze some of their intriguing dynamical features. A number of interesting future directions are highlighted.
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44

Neagu, Eugen R., M. Carmo Lança, and José N. Marat-Mendes. "New Experimental Facts Concerning the Thermally Stimulated Discharge Current in Dielectric Materials." Materials Science Forum 587-588 (June 2008): 328–32. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.328.

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The thermally stimulated discharge current (TSDC) method is a very sensitive and a very selective technique to analyze dipole disorientation and the movement of de-trapped space charge (SC). We have proposed a variant of the TSDC method, namely the final thermally stimulated discharge current (FTSDC) technique. The experimental conditions can be selected so that the FTSDC is mainly determined by the SC de-trapping. The temperatures of the maximum intensity of the fractional polarization peaks obtained at low temperature, in the range of the local (secondary) relaxation, are in general about 10 to 20 K above the poling temperature. Measurements of the FTSDC in a wide temperature range demonstrate the existence of an apparent peak at a temperature Tma shifted with about 10 to 30 K above the charging temperature Tc. The shift of Tma with respect to Tc depends on the experimental conditions. The peak width at the half maximum intensity decreases as Tc increases and the thermal apparent activation energy increases. The variations are not monotonous revealing the temperature range where the molecular motion is stronger and consequently the charge trapping and de-trapping processes are affected. Our results demonstrate that there is a strong similarity between the elementary peaks obtained by the two methods, and the current is mainly determined by SC de-trapping. Even the best elementary peaks are not fitted very well by the analytical equation, indicating that the hypothesis behind this equation have to be reconsidered.
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45

Semerak, Steven N., and Curtis W. Frank. "Energy migration in the aromatic vinyl polymers. 5. Poly(2-vinyl naphthalene) and polystyrene." Canadian Journal of Chemistry 63, no. 6 (June 1, 1985): 1328–32. http://dx.doi.org/10.1139/v85-225.

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Electronic energy migration in pure poly(2-vinyl naphthalene) (P2VN) is analyzed in terms of a theory for three-dimensional transport and trapping in a homogeneous system of randomly distributed chromophores. A simpler theory for 3-D transport on a spatially periodic lattice, which was applied previously to polystyrene (PS) gave self-contradictory results for P2VN because of higher transport rates in P2VN. The fraction of rings in excimer-forming sites (EFS) in pure P2VN, analyzed by the former theory, is found to be 0.072 – moderately larger than the single-chain fraction of 0.026. In contrast, the EFS ring fraction in pure PS was 0.33, much larger than the single-chain fraction of 0.051. This reflects the reduced probability, relative to a phenyl ring pair, of packing a naphthyl ring pair into the necessary sandwich arrangement in the pure polymers. Energy migration in very dilute, miscible blends containing P2VN is analyzed by a one-dimensional transport model, which was applied previously to similar blends containing PS. The nearest-neighbor migration rates obtained from the data for both P2VN and PS are about one hundred times higher than the expected dipole–dipole rates. This suggests that (1) migration is not limited to nearest-neighbor rings, (2) the morphology of the dilute blends does not consist of isolated chains of the aromatic vinyl polymers, or (3) short-range electronic interactions other than dipole–dipole are involved in energy migration.
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46

Weng, Ming Hung, Rajat Mahapatra, Alton B. Horsfall, Nicolas G. Wright, Paul G. Coleman, and C. P. Burrows. "Trap Assisted Conduction in High K Dielectric Capacitors on 4H-SiC." Materials Science Forum 556-557 (September 2007): 679–82. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.679.

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The characteristic of trap assisted conduction and interface states for a Pd/TiO2/SiO2/SiC structure has been investigated at temperatures up to 500 °C. Thermally oxidized Ti/SiO2 gate capacitors fabricated by dry oxidation in O2 were studied. The electrical measurements show the current conduction through this capacitor structure is controlled by a trap assisted conduction mechanism at low bias and the barrier height (φA) between the metal and the TiO2 was extracted. The current density in the dielectric stacks is also shown to be strongly temperature dependent. The results demonstrate that the formation of a charge dipole under the Pd contact is responsible for barrier height and not any changes in the behaviour of the TiO2 film itself, such as a change in concentration of trapping centres. The reported results indicate electron trapping property across the SiO2 layer is consistent with fitting experimental results to the trap assisted conduction model.
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47

Smith, Joseph C., Seth T. Rittenhouse, Ryan M. Wilson, and Brandon M. Peden. "Bogoliubov theory of a Bose–Einstein condensate of rigid rotor molecules." Journal of Physics B: Atomic, Molecular and Optical Physics 54, no. 20 (October 20, 2021): 205302. http://dx.doi.org/10.1088/1361-6455/ac34dd.

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Abstract We consider a BEC of rigid rotor molecules confined to quasi-2D through harmonic trapping. The molecules are subjected to an external electric field which polarizes the gas, and the molecules interact via dipole–dipole interactions. We present a description of the ground state and low-energy excitations of the system including an analysis of the mean-field energy, polarization, and stability. Under large electric fields the gas becomes fully polarized and we reproduce a well known density-wave instability which arises in polar BECs. Under smaller applied electric fields the gas develops an in-plane polarization leading to the emergence of a new global instability as the molecules ‘tilt’. The character of these instabilities is clarified by means of momentum-space density–density structure factors. A peak at zero momentum in the spin–spin structure factor for the in-plane component of the polarization indicates that the tilt instability is a global phonon-like instability.
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48

Zang, Huidong, Mihail Cristea, Xuan Shen, Mingzhao Liu, Fernando Camino, and Mircea Cotlet. "Charge trapping and de-trapping in isolated CdSe/ZnS nanocrystals under an external electric field: indirect evidence for a permanent dipole moment." Nanoscale 7, no. 36 (2015): 14897–905. http://dx.doi.org/10.1039/c5nr03714j.

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49

Zhou, X. Z., T. A. Fritz, Q. G. Zong, Z. Y. Pu, Y. Q. Hao, and J. B. Cao. "The cusp: a window for particle exchange between the radiation belt and the solar wind." Annales Geophysicae 24, no. 11 (November 22, 2006): 3131–37. http://dx.doi.org/10.5194/angeo-24-3131-2006.

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Abstract. The study focuses on a single particle dynamics in the cusp region. The topology of the cusp region in terms of magnetic field iso-B contours has been studied using the Tsyganenko 96 model (T96) as an example, to show the importance of an off-equatorial minimum on particle trapping. We carry out test particle simulations to demonstrate the bounce and drift motion. The "cusp trapping limit" concept is introduced to reflect the particle motion in the high latitude magnetospheric region. The spatial distribution of the "cusp trapping limit" shows that only those particles with near 90° pitch-angles can be trapped and drift around the cusp. Those with smaller pitch angles may be partly trapped in the iso-B contours, however, they will eventually escape along one of the magnetic field lines. There exist both open field lines and closed ones within the same drift orbit, indicating two possible destinations of these particles: those particles being lost along open field lines will be connected to the surface of the magnetopause and the solar wind, while those along closed ones will enter the equatorial radiation belt. Thus, it is believed that the cusp region can provide a window for particle exchange between these two regions. Some of the factors, such as dipole tilt angle, magnetospheric convection, IMF and the Birkeland current system, may influence the cusp's trapping capability and therefore affect the particle exchanging mechanism. Their roles are examined by both the analysis of cusp magnetic topology and test particle simulations.
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50

Padovani, Andrea, Antonio Arreghini, Luca Vandelli, Luca Larcher, Geert Van den bosch, and Jan Van Houdt. "Evidences for vertical charge dipole formation in charge-trapping memories and its impact on reliability." Applied Physics Letters 101, no. 5 (July 30, 2012): 053505. http://dx.doi.org/10.1063/1.4740255.

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