Aharonov-Bohm Research Articles

Effects of rotation and Coulomb-type potential on the spin-1/2 Aharonov–Bohm problem

In this work, we investigate how both rotation and a Coulomb potential affect the quantum mechanical description of a spin-$1/2$ particle in the presence of the Aharonov-Bohm effect. We employ the method of the self-adjoint extensions in the framework of the Pauli-Schr\"odinger equation. We discuss the role of the spin degree of freedom on this problem, find the energy spectrum, and investigate the results in detail.

Klein–Gordon oscillator with magnetic and quantum flux fields in non-trivial topological space-time

The relativistic quantum motions of the oscillator field (via the Klein–Gordon oscillator equation) under a uniform magnetic field in a topologically non-trivial space-time geometry are analyzed. We solve the Klein–Gordon oscillator equation using the Nikiforov-Uvarov method and obtain the energy profile and the wave function. We discuss the effects of the non-trivial topology and the magnetic field on the energy eigenvalues. We find that the energy eigenvalues depend on the quantum flux field that shows an analogue of the Aharonov–Bohm effect. Furthermore, we obtain the persistent currents, the magnetization, and the magnetic susceptibility at zero temperature in the quantum system defined in a state and show that these magnetic parameters are modified by various factors.

Gravitational Aharonov–Bohm effect in a matter-wave interferometer

Gravitational Aharonov–Bohm effect in a matter-wave interferometer

HLA class II antibody activation of endothelial cells induces M2 macrophage differentiation in peripheral blood.

Donor-specific human leukocyte antigen (HLA) class II antibodies (HLA-II Abs) combined with allogeneic endothelial cells (ECs) mediate high-risk rejection in kidney transplant patients. Macrophage accumulation is a significant histological feature of antibody-mediated rejection (AMR) in kidney transplant patients. Here, we further investigated the effect of HLA-II Abs on macrophage phenotypes to provide theoretical basis for clinical treatment of AMR. We prepared an experimental model containing HLA-II Ab-stimulated microvascular ECs and peripheral blood mononuclear cells (PBMCs) co-culture and explored the potential relationship of HLA-II Ab, ECs activation, and macrophage differentiation. Immune phenotype of macrophage subsets was analyzed and quantified by flow cytometry. HLA-II Ab activation of ECs induces M2 macrophage differentiation signal pathways which were investigated by qPCR and western blotting. The stimulation of ECs by F(ab')2 fragment of HLA-II Abs led to phosphorylation of PI3K, Akt, and mTOR, which mediated IL-10, ICAM-1, VCAM-1 secretion. The enhanced ICAM-1 and IL-10 promoted the migration of PBMCs and their differentiation into CD68+ and CD163+ (M2-type) macrophages, respectively, but not CD86+ macrophages. These findings revealed the PI3K/Akt/mTOR signal pathways activated by HLA-II Abs in ECs and the immune regulation ability of HLA-II Abs to induce PBMC differentiation.

Induced Vacuum Energy Density of Quantum Charged Scalar Matter in the Background of an Impenetrable Magnetic Tube with the Neumann Boundary Condition

We consider the vacuum polarization of a charged scalar matter field outside the tube with magnetic flux inside. The tube is impenetrable for quantum matter, and the perfectly rigid (Neumann) boundary condition is imposed at its surface. We write expressions for the induced vacuum energy density for the case of a space with arbitrary dimension and for an arbitrary value of the magnetic flux. We do the numerical computation for the case of a half-integer flux value in the London flux units and the (2 + 1)-dimensional space-time. We show that the induced vacuum energy of the charged scalar matter field is induced, if the Compton wavelength of the matter field exceeds the transverse size of the tube considerably. We show that the vacuum energy is periodic in the value of the magnetic flux of the tube, providing a quantumfield-theoretical manifestation of the Aharonov–Bohm effect. The dependencies of the induced vacuum energy upon the distance from the center of the tube for different values of its thickness are obtained. The results are compared to those obtained earlier in the case of the perfectly reflecting (Dirichlet) boundary condition. It is shown that the value of the induced vacuum energy density in the case of the Neumann boundary condition is greater than in the case of the Dirichlet boundary condition.

Engineered apoptotic bodies hitchhiking across the blood-brain barrier achieved a combined photothermal-chemotherapeutic effect against glioma.

Background: Glioma as a highly lethal tumor is difficult to treat since the blood-brain barrier (BBB) restricts drug delivery into the brain. It remains a huge need for developing strategies allowing drug passage across the BBB with high efficacy. Methods: Herein, we engineered drug-loaded apoptotic bodies (Abs) loaded with doxorubicin (Dox) and indocyanine green (ICG) to cross the BBB for the treatment of glioma. The confocal laser scanning microscopy was used to characterize the structure and evaluate the hitchhiking effect of the Abs. The in vivo BBB-crossing ability and photothermal-chemotherapeutic effect of the drug-loaded Abs were investigated in mice orthotopic glioma model. Results: Engineered Abs loaded with Dox and ICG were successfully prepared. The Abs were phagocytized by macrophages, actively penetrate the BBB in vitro and in vivo utilizing the hitchhiking effect. The whole in vivo process was visualized by near-infrared fluorescence signal with a signal-to-background ratio of 7 in a mouse model of orthotopic glioma. The engineered Abs achieved a combined photothermal-chemotherapeutic effect, leading to a median survival time of 33 days in glioma-bearing mice compared to 22 days in the control group. Conclusions: This study presents engineered drug carriers with the ability to hitchhike across the BBB, providing new opportunities for the treatment of glioma.

Quantum dispersion properties of eigenmodes in semiconductor nanotubes with dielectric filling in dc magnetic field

Dispersion properties of electromagnetic eigenmodes in a semiconductor nanotube (with quadratic electron dispersion law) filled by a nonmagnetic dielectric and placed in a coaxial dc magnetic field are studied theoretically. A new quantum electrodynamical phenomenon is predicted. Namely, it is shown that increase in the electron density n02D in the nanotube results in the appearance of new branches in the eigenmodes spectrum. These branches arise in a bifurcation manner at some critical values of n02D, when a new electron energy subzone starts to fill in. The number of branches monotonously increases with growth n02D and oscillates with increase in the number of magnetic flux quanta through the nanotube (i.e., a peculiar Aharonov–Bohm effect takes place). We also found that the dispersion curves have parts with anomalous dispersion. The analytical expression for electron energy loss due to the excitation of eigenmodes under the Cherenkov resonance condition is derived and numerically analyzed.

Effects of physical active breaks on vigilance performance in schoolchildren of 10-11 years

Purpose.The main aim of this research analyses acute PE based on AB and how it might have an exponential affect during the school day.Methods.A total of 46 healthy schoolchildren (age = 10.75 ± 0.65 years) participated in this study, receiving a traditional lesson of 25 min during the assigned class followed by 10 min of a free-reading task (Control Condition) or 10 min of physical activity based on motor games (Active-Break Condition). Immediately following the assigned 10-min. intervention, the participants performed the Psychomotor Vigilance Task (PVT) then finally returned to perform the traditional lesson for the remaining 15 min. Significant differences were found in the PVT.Results.Our results show the main effect of the Active-Break Condition group responding faster (365 ms) than the students in the Control Condition group (379 ms), <i>F</i><sub>(1.45)</sub> = 24.18, <i>p</i> = 0.001, η<sup>2</sup> = 0.34. The present study demonstrated that a student’s vigilance performance changes after of AB of 10 min (compared to the Control Condition) and that AB improves the efficiency of vigilance in schoolchildren of 10–11 years.Conclusions.Although limited, our results could help researchers and teachers more accurately apply AB to more properly improve their students’ vigilance. More studies with EEG analysis and neuroimaging are necessary to understand the effects of AB in young students.

Fingerprint of Majorana Zero Modes through Nonlocal Measurements

The enhancement and robustness of the 2π periodic Aharonov-Bohm effect can serve as a nonlocal probe of Majorana zero modes in topological superconductors that are not restricted by fermion parity.

Radial solution of Schrödinger equation with generalized inverse Hulthen and Yukawa potentials in topological defect

In this work, the generalized inverse Yukawa potential is used to explore the radial Schrödinger equation in three dimensions in a topological defect caused by a point-like global monopole. We analyze the quantum system under the influence of the quantum flux field and see that the angular quantum number l is shifted, that is, which shows an analogue to the Aharonov-Bohm effect. We use a suitable approximation scheme in the centrifugal and reciprocal terms that appear in the radial equation and solve the equation through the parametric Nikiforov-Uvarov method. Afterwards, we consider the potential of the superposition of generalized inverse Hulthen and generalized inverse Yukawa potentials in the quantum system and solve the radial equation using the same technique. The obtained eigenvalue solutions are analyzed for the topological defects of the geometry and the quantum flux and see that the results get shifted in comparison to the flat space case with these potentials.

Radial solution of Schrödinger equation with generalized inverse Hulthen and Yukawa potentials in topological defect

In this work, the generalized inverse Yukawa potential is used to explore the radial Schrödinger equation in three dimensions in a topological defect caused by a point-like global monopole. We analyze the quantum system under the influence of the quantum flux field and see that the angular quantum number l is shifted, that is, which shows an analogue to the Aharonov-Bohm effect. We use a suitable approximation scheme in the centrifugal and reciprocal terms that appear in the radial equation and solve the equation through the parametric Nikiforov-Uvarov method. Afterwards, we consider the potential of the superposition of generalized inverse Hulthen and generalized inverse Yukawa potentials in the quantum system and solve the radial equation using the same technique. The obtained eigenvalue solutions are analyzed for the topological defects of the geometry and the quantum flux and see that the results get shifted in comparison to the flat space case with these potentials.

Hybrid normal-superconducting Aharonov-Bohm quantum thermal device

We propose and theoretically investigate the behavior of a ballistic Aharonov-Bohm (AB) ring when embedded in a N-S two-terminal setup, consisting of a normal metal (N) and superconducting (S) leads. This device is based on available current technologies and we show in this work that it constitutes a promising hybrid quantum thermal device, as a quantum heat engine and quantum thermal rectifier. Remarkably, we evidence the interplay of single-particle quantum interferences in the AB ring and of the superconducting properties of the structure to achieve the hybrid operating mode for this quantum device. Its efficiency as a quantum heat engine reaches of the Carnot efficiency, and we predict a thermal rectification factor attaining 350%. These results make this device highly promising for future phase-coherent caloritronic nanodevices.

On the Quantization of AB Phase in Nonlinear Systems.

Self-intersecting energy band structures in momentum space can be induced by nonlinearity at the mean-field level, with the so-called nonlinear Dirac cones as one intriguing consequence. Using the Qi-Wu-Zhang model plus power law nonlinearity, we systematically study in this paper the Aharonov-Bohm (AB) phase associated with an adiabatic process in the momentum space, with two adiabatic paths circling around one nonlinear Dirac cone. Interestingly, for and only for Kerr nonlinearity, the AB phase experiences a jump of π at the critical nonlinearity at which the Dirac cone appears and disappears (thus yielding π-quantization of the AB phase so long as the nonlinear Dirac cone exists), whereas for all other powers of nonlinearity, the AB phase always changes continuously with the nonlinear strength. Our results may be useful for experimental measurement of power-law nonlinearity and shall motivate further fundamental interest in aspects of geometric phase and adiabatic following in nonlinear systems.

The metaphysics of fibre bundles

Recently, Dewar (2019) has suggested that one can apply the strategy of ‘sophistication’—as exemplified by sophisticated substantivalism as a response to the diffeomorphism invariance of General Relativity—to gauge theories such as electrodynamics. This requires a shift to the formalism of fibre bundles. In this paper, I develop and defend this suggestion. Where my approach differs from previous discussions is that I focus on the metaphysical picture underlying the fibre bundle formalism. In particular, I aim to affirm the physical reality of gauge properties. I argue that this allows for a local and separable explanation of the Aharonov-Bohm effect. Its puzzling features are explained by a form of holism inherent to fibre bundles.

Hellmann potential and topological effects on non-relativistic particles confined by Aharonov–Bohm flux field

In this analysis, we investigate the quantum motions of a non-relativistic particle confined by the Aharonov–Bohm flux field with Hellmann potential (Coulomb plus Yukawa potential) in a topological defect space-time produced by a point-like defect. We employ a suitable approximation scheme in the centrifugal and reciprocal terms that appear in the radial equation and determine the eigenvalue solution using the parametric Nikiforov–Uvarov method. Afterwards, we study the quantum system with an attractive Coulomb potential and obtained the eigenvalue solution using the same NU-method. These eigenvalue solutions are analysed and see the effects of topological defects produced by a point-like defect and the AB-flux field with these potentials. We also see that in addition to the topological effects, the energy levels shift more by the magnetic flux field, which gives us an analogue of the Aharonov–Bohm effect for the bound state. Finally, we plot a few graphs of the energy levels and the radial wave function with different parameters, such as the topological defect, the magnetic flux field, and the screening parameter, and discuss the results.

Alternanthera brasiliana L. extract alleviates carbon tetrachloride-induced liver injury and fibrotic changes in mice: Role of matrix metalloproteinases and TGF-β/Smad axis

Ethnopharmacological relevanceAlternanthera brasiliana L. is a flowering plant belonging to the family Amaranthaceae and is popularly known as “penicillin”. It is used in folk medicine to treat infections, coughs, wound healing, and inflammatory diseases.Aim of the study: We investigated the effect of Alternanthera brasiliana L. leaves hydroalcoholic extract (AB) against oxidative stress, inflammation, and fibrotic changes in an experimental model of carbon tetrachloride (CCl4)-induced liver injury and fibrosis in mice. Materials and methodsThirty-six male Balb/C mice were randomized into five groups: normal control, AB control, CCl4 control, CCl4 + AB-200 mg/kg, and CCl4 + AB-400 mg/kg. In mice, liver injury was induced by intraperitoneal injection of CCl4 (20% in corn oil, 5 ml/kg body weight) thrice a week for six consecutive weeks. AB extract at two doses (200 mg/kg and 400 mg/kg body weight) was administered orally for six consecutive weeks. Liver injury-related serum markers (ALT, AST, ALP), antioxidants (GSH, GST, SOD, and vitamin C), pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-18, ultrasonographic and histological alterations, proteins of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinase-1 (TIMP-1), nuclear factor-κB (p65) (NF-κB), nod-like receptor protein 3 (NLRP3), and TGF-β/Smad signaling were accessed. LC-Q-TOF-MS/MS analysis of AB was performed. ResultsAB treatment significantly decreased the CCl4-induced rise in serum ALT, AST, and ALP activities and improved the histological alterations. Compared with the CCl4-treated group, treatment with AB significantly restored the hepatic antioxidants and reduced the pro-inflammatory cytokines in the liver. The antioxidant activity of AB may be attributed to its terpenoid constituents, which was confirmed by LC-Q-TOF-MS/MS analysis. The CCl4-induced rise in expression of MMP-2 and MMP-9 and decrease in TIMP-1 were markedly restored in the AB-treated groups. Further findings revealed a significant reduction in the protein levels of phospho–NF–κB (p65), NLRP3, TGF-β, pSmad2/3, collagen I, and α-smooth muscle actin (α-SMA) in the AB treatment groups. ConclusionsThe hepatoprotective effect of AB may be attributed to the high content of terpenoid compounds and alleviates liver injury and associated fibrotic changes through modulating MMPs, NF-κB (p65), and the TGF-β/Smad axis.

Amyloid‐mediated TRAIL DRs activation leads to progressive degeneration of cerebral vascular smooth muscle cells

AbstractBackgroundVascular accumulation of amyloid beta (Ab) leads to loss of vascular smooth muscle cells (VSMC) in cerebral arteries via unknown mechanisms, promoting cerebral blood flow alterations and contributing to cognitive impairment. Ab species with different lengths or mutated familial variants may have differential effects on VSMC. Ab1‐42, the main pathogenic form of amyloid in the AD brain with the highest propensity to form aggregates, increased apoptosis in brain vascular cells whereas Ab1‐40 was found to be less toxic. By comparison, the familial Ab variant E22Q, induced the most cell death of all the amyloid variants tested. However, there has been little progress in defining the pathways leading to VSMC degeneration in AD and related disorders. The aim of this study was to identify Ab‐mediated cell death mechanisms in VSMC.MethodHuman cerebral VSMC were treated with pre‐oligomerized variants of Ab for 2‐8hrs (acute treatment) and 24‐72hrs (chronic treatment). Analysis of fragmented nucleosomes and visualization of cytochrome c (Cyt. C) expression by immunocytochemistry were used to measure apoptosis. Activation of intrinsic and extrinsic apoptotic pathways were examined by western blot and caspase‐glo assays. The effects of Ab on mitochondrial function were examined using a Seahorse XF96 Analyzer and TMRM fluorescent dye in live cells.ResultsAcute Ab treatment in VSMC up‐regulated tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) death receptors DR4 and DR5 with activation of caspase 8 and transient activation of Nuclear Factor k B (NF‐kB). DR4 and DR5 expression remained high with chronic Ab treatment and lead to caspase activation followed by Cyt. C release and apoptosis. 24hrs of Ab treatment also decreased mitochondrial membrane potential and significantly impaired mitochondrial respiration.ConclusionAcute exposure of VSMC to Ab causes up‐regulation and activation of DR4/DR5, that, over time, results in mitochondrial dysfunction, caspase activation and apoptosis. Our data suggests that an early and transient activation of NF‐kB may also contribute to the toxic effects of Ab, possibly by inducing pro‐inflammatory pathways in the neurovascular unit.

Topological defects with generalized Hulthen–Coulomb-inverse quadratic Yukawa potential on eigenvalue solution under Aharonov–Bohm flux field

In this work, we solve the radial Schrödinger wave equation in three dimensions under Aharonov–Bohm (AB)-flux field with potential superposition of generalized q-deformed Hulthen potential, Coulomb potential, and inverse quadratic Yukawa potential in a point-like defect. We determine the approximate eigenvalue solution using the parametric Nikiforov–Uvarov (NU) method and analyze the effects of topological defect and the magnetic flux field with this superposed potential. We show an analogous of the AB effect because the eigenvalue solution depends on the geometric quantum phase and bound state solutions are possible under condition. Finally, we utilize the approximate eigenvalue solution to some molecular potential models, such as Deng–Fan potential and inverse quadratic Hulthen potential and analyze the effects on the energy levels and the radial wave functions.

Aharonov-Bohm Caging and Inverse Anderson Transition in Ultracold Atoms.

Aharonov-Bohm (AB) caging, a special flat-band localization mechanism, has spurred great interest in different areas of physics. AB caging can be harnessed to explore the rich and exotic physics of quantum transport in flatband systems, where geometric frustration, disorder, and correlations act in a synergetic and distinct way than that in ordinary dispersive band systems. In contrast to the ordinary Anderson localization, where disorder induces localization and prevents transport, in flat band systems disorder can induce mobility, a phenomenon dubbed inverse Anderson transition. Here, we report on the experimental realization of the AB cage using a synthetic lattice in the momentum space of ultracold atoms with tailored gauge fields, and demonstrate the geometric localization due to the flat band and the inverse Anderson transition when correlated binary disorder is added to the system. Our experimental platform in a many-body environment provides a fascinating quantum simulator where the interplay between engineered gauge fields, localization, and topological properties of flat band systems can be finely explored.

Thermo-magnetic properties of Manning–Rosen plus inversely quadratic Yukawa potential under the influence of magnetic and Aharonov–Bohm (AB) flux fields

Thermo-magnetic properties of Manning–Rosen plus inversely quadratic Yukawa potential under the influence of magnetic and Aharonov–Bohm (AB) flux fields