Scaling in the Problem of Capture of Diffusing Particles in Absorbing Traps in an Electric Field

Journal of Experimental and Theoretical Physics - The asymptotic form of particle survival probability in media with absorbing traps in an electric field has been analyzed. The asymptotic behavior...     

Universal Temporal Dependence of Survival Probability for Diffusing Particles in Multidimensional Media with Absorbing Traps in an Electric Field

The effect of electric-field-induced reduction of the “effective” dimension is detected in the multidimensional problem of diffusion in a medium with absorbing traps. An effective transition to the 1D case occurs due to directional motion of a particle when it begins to dominate over diffusion. A universal “1D” dependence of the particle survival probability in a multidimensional medium with absorbing traps over long times has been established.     

On the Gauge Invariance of the Transition Probability of a Charged Particle in Electromagnetic Field

This paper suggests a principle to find a unitary operator U which transforms non-physical quantity,zero-potential Hamiltonian Ho, into true physical quantity UHoU for a charged particle in classical electromagneticfield, and puts forward a unified form of constructing gauge-independent transition probabilities in this case. Differentmethods correspond to different unitary operators which satisfy the above-mentioned principle.     

New Temporal Asymptotics of the Survival Probability in the Capture of Particles in Traps in Media with Anomalous Diffusion

Journal of Experimental and Theoretical Physics - The problem of capture of particles experiencing normal diffusion as well as anomalous subdiffusion to absorbing traps has been investigated. It is...     

Effect of Ergodic and Non-Ergodic Fluctuations on a Charge Diffusing in a Stochastic Magnetic Field

In this paper, we study the basic problem of a charged particle in a stochastic magnetic field. We consider dichotomous fluctuations of the magnetic field where the sojourn time in one of the two states are distributed according to a given waiting-time distribution either with Poisson or non-Poisson statistics, including as well the case of distributions with diverging mean time between changes of the field, corresponding to an ergodicity breaking condition. We provide analytical and numerical results for all cases evaluating the average and the second moment of the position and velocity of the particle. We show that the field fluctuations induce diffusion of the charge with either normal or anomalous properties, depending on the statistics of the fluctuations, with distinct regimes from those observed, e.g., in standard Continuous-Time Random Walk models.     

Imaging of an Absorbing Object Embedded in a Dense Scattering Medium by Diffusing Light Topography

A new and simple imaging method for an absorbing object embedded in a dense scattering medium is proposed. The distinct characteristic is the positive usage of the diffusing light in the dense scattering medium to image the absorbing object. The principle is based on the equivalence between a probability distribution function of the path-length and a backscattered intensity distribution integrated spatially in the boundary plane between the medium and the air. The usefulness of the proposed method is experimentally confirmed for a modified pyramidal object painted black and thin tubes filled with black and red inks. The conditions under which the better image can be reconstructed are confirmed from the results of experiments and simulations. It is finally shown that our proposed method is capable of imaging the map of blood vessels distributed under the skin layers.     

Global Behavior of Field Line and Particle Diffusion in a Stochastic Magnetic Field

Global behavior of field line diffusion in a stochastic magnetic field is obtained. Stochastic motion of particles undergoing mutural random collisions in the stochastic magnetic field is studied for the whole time range. The field line as wel as the particle diffusion coefficients are calculated to the sixth order of the relative magnitude of the fluctuating magnetic field.     

A Charged Particle in an Electric Field in the Probability Representation of Quantum Mechanics

The Green's function and linear integrals of motion for a charged particle moving in an electric field are discussed. The Wigner functions and tomograms of the stationary states of the charged particle are obtained. The relationship between the quantum propagators for the Schrödinger evolution equation, the Moyal evolution equation, and the evolution equation in the tomographic-probability representation for a charged particle moving in an electric field is discussed.     

Chaotic Dynamics of Test Particle in the Gravitational Field with Magnetic Dipoles

We investigate the dynamics of the test particle in the gravitational field with magnetic dipoles in thispaper. At first we study the gravitational potential by numerical simulations. We find, for appropriate parameters, thatthere are two different cases in the potential curve, one of which is the one-well case with a stable critical point, and theother is the three-well case with three stable critical points and two unstable ones. As a consequence, the chaotic motionwill rise. By performing the evolution of the orbits of the test particle in the phase space, we find that the orbits of thetest particle randomly oscillate without any periods, even sensitively depending on the initial conditions and parameters.chaotic motion of the test particle in the field with magnetic dipoles becomes even obvious as the value of the magneticdipoles increases.     

Small Mass Asymptotics for a Charged Particle in a Magnetic Field and Long-Time Influence of Small Perturbations

We consider small mass asymptotics of the motion of a charged particle in a potential combined with a magnetic field. After an appropriate regularization, a Smoluchowski-Kramers type approximation is established. This approximation allows to study long-time influence on the motion of various perturbations, deterministic and stochastic. In particular, even in the case of pure deterministic perturbations, the long-time evolution of the perturbed system can be stochastic.     

霍尔元件线度对磁场测量影响的研究

在原有霍尔效应原理的基础上,利用微积分的基本方法和相关的物理知识推导非均匀磁场中利用霍尔效应测量磁场的理论公式,并结合该公式理论解释实验中对于霍尔元件线度的要求,以及说明非均匀磁场的测量对霍尔元件线度的要求,从而说明实验中经常遇到的一类问题——平均值问题。     

Perturbations of the Motion of a Charged Particle in a Noisy Magnetic Field

We consider deterministic and stochastic perturbations of the motion of a charged particle in a noisy magnetic field. The noise in the magnetic field leads to the mixing on the energy surfaces and allows to apply averaging principle. We describe long-time energy evolution and its metastable states for a given initial energy and a time scale.     

The Motion of a Nonferromagnetic Particle in a Periodic Magnetic Field

The motion of a spherical nonferromagnetic particle in an axially symmetric periodic permanent magnetic field is considered. It is shown that in this field configuration the focusing of fast particles and the mass separation of a particle beam are realizable.     

A Particle in a Magnetic Field of an Infinite Rectilinear Current

We consider the Schrödinger operator H=(i+A)² in the space L ₂(R ³) with a magnetic potential A created by an infinite rectilinear current. We show that the operator H is absolutely continuous, its spectrum has infinite multiplicity and coincides with the positive half-axis. Then we find the large-time behavior of solutions exp(–i H t)f of the time dependent Schrödinger equation. Our main observation is that a quantum particle has always a preferable (depending on its charge) direction of propagation along the current. Similar result is true in classical mechanics.     

Electrical Properties of Nanostructured Magnetic Colloid and Influence of Magnetic Field

We investigate the electrical properties of the nanostructured magnetic colloid without and with magnetic field. The competition between the directional motion of the charged magnetic nanoparticles and other minor nonmagnetic impurities （also small amount of ions） under applied voltage and their random orientation due to thermal activation is implemented to elaborate the electrically conduction mechanism under zero magnetic field. Two equivalent electric circuits are employed for explaining the charging and discharging processes. The tunnelling conduction mechanism upon application of externally magnetic field may exist in the nanostructured magnetic colloid. The alternation of the two conduction mechanisms accounts for the current spikes when the magnetic field is switched on or off. This work presents the peculiar electrical phenomena of the magnetically colloidal system.     

Influence of Quantum Effects on the Magnetic Field Behavior in Overdense Plasma

We study the conditions for the anomalous transmission of electromagnetic waves through quantum overdense plasma. We show that this anomalous transmission is triggered due to the excitation of surface waves, as was observed in the classical overdense plasma. The conditions for the excitation of surface waves are obtained by studying the dispersion relation within the framework of quantum hydrodynamics. The corresponding consequences at the classical limits are consistent with the previous studies. In comparison with the classical regimes, the quantum dispersion curve exhibits an asymptotic behavior which indicates significant effects, in particular, at large wavelengths. Herein, to create the required evanescent waves, we consider the quantum plasma to be placed between two ordinary prisms and dielectrics. The effects of the main parameters, such as the permittivity of the prisms and dielectrics and the Fermi velocity, on the rate of the transmission and the magnetic field propagation are also evaluated.     

Influence of Magnetic Field on Qutrit Teleportation under Intrinsic Decoherence

We study qutrit teleportation through a qutrit xyz chain, in the presence of intrinsic decoherence and a non-homogeneous magnetic field. We study the effects of intrinsic phase change, magnetic field and entanglement of the initial state of the channel. It is observed that while the intrinsic phase change and the non-homogeneity of the magnetic field have adverse effects on the teleportation fidelity, the entanglement of the initial state of the channeled enhances the latter. Moreover, the intrinsic decoherence may remove the ripples from the time curve that is delivered by the Schrödinger channel.