26 research outputs found

    Localized Excitation of Single Atom to a Rydberg State with Structured Laser Beam for Quantum Information

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    Sufficient control over the excitation of the Rydberg atom as a quantum memory is crucial for the fast and deterministic preparation and manipulation of the quantum information. Considering the Laguerre-Gaussian (LG) beam spatial features, localized excitation of a four-level atom to a highly excited Rydberg state is presented. The position-dependent AC-Stark shift of the first and Rydberg state in the effective quadrupole two-level description of a far-detuned three-photon Rydberg excitation results in a steep trapping potential for Rydberg state. The transfer of optical orbital angular momentum from LG beam to the Rydberg state via quadrupole transition in the last Rydberg excitation process offers a long-lived and controllable qudit quantum memory. The effective quadrupole Rabi frequency is presented as a function of ratio of the first to Rydberg excitation laser beam waist and the center of mass position inside the trap. It depicts high accuracy of detecting Rydberg atom at the center of the trap, which can pave the way for implementation of high-fidelity qudit gate

    Efficacy of Granisetron versus Sufentanil on Reducing Myoclonic Movements Following Etomidate: A double-blind, randomized clinical trial

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    Objective: Etomidate-induced myoclonus occurs in up to 85% of patients under general anesthesia. This type of myoclonus can induce significant clinical and economic problems in patients with special conditions. Hence, to reduce the intensity of myoclonus movements, the present study was conducted to compare the effectiveness of granisetron and sufentanil on reducing the intensity of etomidate-induced myoclonic movements. Methods: This double-blind randomized clinical trial study consisted of 96 adult patients. Using block randomization, subjects were divided into three groups of 32: the group receiving granisetron 40 μg / kg (group G), the group receiving sufentanil 0.2 μg / kg (group S), and the control group who did not receive the pretreatment (group C). Patients received these medications as pretreatments 120 seconds before induction with etomidate. After injection of etomidate with a dose of 0.3 mg/kg, the incidence of myoclonus was evaluated. After evaluating the myoclonus, the full dose of narcotics (fentanyl 1 μg / kg) and muscle relaxants (atracurium 0.5 mg/kg) were administered to patients, and a suitable airway was established for them. Results: The findings indicated that granisetron reduced the intensity and incidence of myoclonic movements more than sufentanil. In addition, myoclonic movements were observed at a significantly higher intensity in the control group (P=0.001). Conclusion: The results obtained from the current study indicate that granisetron and sufentanil as pretreatments are effective for reducing myoclonus in patients. Keywords: Granisetron; Sufentanil; Etomidate; Myoclonus; Movement

    Paraxial propagation in amorphous optical media with screw dislocation

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    We study paraxial beam propagation parallel to the screw axis of a dislocated amorphous medium that is optically weakly inhomogeneous and isotropic. The effect of the screw dislocation on the beam's orbital angular momentum is shown to change the optical vortex strength, rendering vortex annihilation or generation possible. Furthermore, the dislocation is shown to induce a weak \textit{biaxial} anisotropy in the medium due to the elasto-optic effect, which changes the beam's spin angular momentum as well as causing precession of the polarization. We derive the equations of motion of the beam and demonstrate the optical Hall effect in the dislocated medium. Its application with regard to determining the Burgers vector as well as the elasto-optic coefficients of the medium is explained

    Ortho keratinized Odontogenic Cyst of Mandible: A Rare Case Report

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    Objective: The Ortho keratinized Odontogenic Cyst (OOC) is a rare lesion originates from dental lamina and clinically, it may be mistaken for many other odontogenic cysts and Tumors. Microscopically, It should be distinguished from KCOT because of differences in biologic behavior and histologic features.Case: An interesting case of OOC arising in the edentulous mandibular right first premolar region of a 55-year-old woman is reported. Under the initial clinical diagnosis of a residual cyst, the excisional biopsy was performed. Because of detection of an orthokeratinized epithelium lining, a definite diagnosis of OOC was made.Conclusion: Microscopic examination is crucial for making the correct diagnosis of such lesions, therefore establishing patients' prognosis accurately

    Senescent CD153+ T Lymphocytes Increase in the Peripheral Blood of Patients with Thromboangiitis Obliterans

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    Background: Buerger’s disease, also known as Thromboangiitis Obliterans (TAO), is a progressive, inflammatory vascular disease with unknown etiology.Objective: To address the degree of T cell immunosenescence in this inflammatory disease, the frequency of senescent T cells expressing CD57 and/or CD153 (CD30L) in patients with TAO.Methods: In this study, nine male cigarette smoker patients with TAO, nine male healthy cigarette smokers, and nine male healthy non-smoker blood donors were enrolled. PBMCs were extracted from the blood of all participants and stored in liquid nitrogen before use. The percentages of senescent T cells were detected by flow cytometry. The results were analyzed using non-parametric statistical tests.Results: The frequencies of senescent CD3+CD4+CD57+CD153+ and CD3+CD4+CD57-CD153+ T cells significantly increased in patients compared with the non-smoker controls (p=0.01 and p=0.04, respectively). The frequency of senescent CD3+CD4-CD57-CD153+ T cells was higher in patients compared with the smoker controls (p=0.02). In patients with TAO, CD57+CD153- cells were more frequent in CD3hiCD4- and CD3hiCD4+ T cells compared with the CD3loCD4- and CD3loCD4+ T cells (p=0.008 and p=0.0002, respectively). Conversely, the frequency of CD57-CD153+ T cells was significantly higher in CD3loCD4- T cells compared with the CD3hiCD4- T cells (p=0.004). The percentage of CD3+CD4+CD57+CD153- T cells correlated negatively with smoking level in smoker controls (p=0.02, Spearman r=-0.80).Conclusion: Elevated frequencies of senescent CD4+CD57+CD153+ and CD4+CD57-CD153+ T cells in patients compared with non-smoker and smoker controls suggest the contribution of immunosenescence in TAO

    Electric field around a metal disk within a microwave resonator: electrostatic approximation

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    In this work, a rectangular resonator cavity with non-ionization electromagnetic radiation at frequency of 2.45 GHz or wavelength of 12.24 cm involving a metal disk has been considered. We have shown electrostatic field is a suitable approximation to study a metal disk within a cavity with alternative field at frequency of 2.45 GHz and it leads to solve Laplace's equation. We have solved this equation in elliptical coordinates in detail considering boundary conditions and determined electric field around the disk. Solving Laplace's equation in elliptical coordinates is the appropriate method for determining electric and magnetic fields in the vicinity of the metals with striped or circular types

    Study of aerosols and molecular extinction effects in ultraviolet DIAL remote sensing in the lower atmosphere

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    Light passing through the atmosphere is scattered and absorbed by the molecules and particles in the atmosphere. This can adversely restrict and limit not only the signal-to-noise ratio (SNR) but also the accuracy and sensitivity of measurements, especially in long-path remote sensing. Usually, in differential absorption lidar (DIAL) techniques, errors are increased mainly because of the different extinction and backscattering properties of the atmosphere at the DIAL probe wavelengths. In this work we have investigated the effects of background aerosol and molecular extinction in DIAL remote sensing in the lower atmosphere for several visibilities at ultraviolet (UV) wavelengths by taking into account the dependence of refraction on the air temperature and pressure. For simplicity, we neglected the spatial inhomogeneity of aerosols in the lower atmosphere. Because of the weak attenuation produced by oxygen and other gaseous atmospheric constituents in this region compared with that from ozone, only ozone is considered as significant among the expected errors. Values for the total attenuation (km−1) at wavelengths 200–400 nm are tabulated for several values of visibility. The acquired results show that the absorption and scattering by the molecules and aerosols vary with wavelength and visibility. The aerosol attenuation in the UV region varies smoothly and thereby errors caused by aerosol scattering can be neglected in remote sensing by UV-DIAL. In addition, aerosols play a very important role in lidar remote sensing in the lower atmosphere by scattering and absorption of radiation, which is considered as a significant factor. At high altitudes, the aerosol concentration is lower than at the ground; the molecular scattering is important, especially for wavelengths greater than 310 nm, where ozone attenuation is not important. The obtained results are important for accurate UV-DIAL measurements of concentration as well as when real-world signals are not available, for example when designing lidar and simulating or when access to real-world signals is not possible

    Dual-wavelength CW diode-end-pumped a-cut Nd:YVO4 laser at 1064.5 and 1085.5 nm

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    A simple and compact dual-wavelength continuous wave (CW) laser-diode end-pumped laser operating simultaneously at 1,064.5 and 1,085.5 nm in a single a-cut Nd:YVO4 has been demonstrated. We have used two Nd:YVO4 crystals with different Nd+3 concentrations and lengths; 0.1 %-14 mm and 0.25 %-12 mm. The maximum total output power of 5 and 6.18 W, including 1,064.5 and 1,085.5 nm, is achieved at the incident pump power of 22 and 18 W, with a slope efficiency 23.3 and 32.9 %, respectively, for the crystals of 0.1 %-14 mm and 0.25 %-12 mm. The calculations show both wavelengths lasing at 1,064.5 and 1,085.5 nm can possess the same threshold when reflectivity of the output coupler at 1,064.5 nm is less than 87.5 % and, at this condition, the reflectivity of the output coupler at 1,085.5 nm increases nearly linearly with that of 1,064.5 nm

    Quadrupole excitation of atoms with tightly focused Laguerre-Gaussian beams

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    This article investigates the quadrupole excitation of a trapped atom exposed to the tightly focused Laguerre-Gaussian (LG) beams with parallel and antiparallel spin angular momentum (SAM) and orbital angular momentum (OAM) under nonparaxial conditions. The Rabi frequency profile of allowed quadrupole transition channels, modified by SAM and OAM interaction, in the focal plane is provided. In the case of antiparallel SAM and OAM, the excitation probability undergoes substantial modification due to the considerable contribution of longitudinal intensity variations in tightly focused condition. The findings offer insights into controlling localized atom transition, including OAM transfer, with potential applications in qudit-based technologies.</p
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