arXiv subjects

Larissa Brizhik

Publications and source records attributed to Larissa Brizhik.

7 recordsLinked to original sources

arXiv2026

General solution of the Dirac equation for electrons bound by a charged atomic chain

The system of electrons bound by a charged atom chain is studied within the Dirac theory. The general analytical solution of the Dirac equation is obtained. Analytical expression for electron energy is derived from which it follows that the principal quantum number can be introduced for electron states in such a system, similar to the case of a hydrogen atom. We prove that electrons bound by the atomic chain, are fully collectivized and the energy can be calculated as a function of the occupation number. The spectral band with the principal quantum number $n$ is shown to be split into $n$ subbands forming the fine structure. The scale of the fine structure splitting is calculated.

cond-mat.other↗

arXiv2026

Impact of magnetic fields on polaron dynamics in low-dimensional systems

We study the impact of an external magnetic field on the long-range electron transport in quasi-one-dimensional materials, such as polypeptides, (semi-) conducting polymers and macromolecules, taking into account the electron-lattice interaction. At relatively strong electron-lattice interaction extra electrons get self-trapped in the deformation potential well and form stable bound states, called large polarons which in the continuum approximation are known as solitons. Here we do not use the continuum approximation but solve the system of discrete nonlinear equations numerically. We show that the impact of a magnetic field on polaron dynamics depends not only on the field strength, but also on the parameter values of the system which define the properties of solitons such as their energy, amplitude and width of localisation. We also study the impact of a magnetic field on a polaron created by a donor complex on a chain.

cond-mat.soft↗

arXiv2024

Bound electron states in a charged chain within the Dirac description

For the first time the exact analytical expressions for the three-dimensional bound electron states in the Coulomb field of the chain consisting of positively charged ions, are obtained within the Dirac description, using the new spinor invariant found for this problem. It is demonstrated that within such approach the coupling between electron spin and its one-dimensional propagation along the chain naturally arise, without any need to include artificially into the equations the so-called spin-orbit interaction.

cond-mat.mes-hall↗

arXiv2024

Soliton radiation and role of the energy dissipation in soliton dynamics in an oscillating magnetic field

Dynamics of the Davydov's soliton in an external oscillating in time magnetic field is studied analytically. It is shown that in a field perpendicular to the molecular chain axis, soliton wavefunction is a product of the electron plane wave in the plane perpendicular to the molecular chain, and longitudinal component of the wavefunction which satisfies the modified nonlinear Schroedinger equation with an extra term determined by the field. It is shown that soliton width and amplitude are constant, while its velocity and phase are oscillating functions of time with the frequency of the main harmonic equal to the magnetic field frequency. It is shown that soliton dynamics has two different regimes at low and high frequencies of the magnetic field as comparing with the characteristic soliton frequency. Due to time-depending velocity and nonzero acceleration, soliton radiates linear waves in both directions from its center of mass. In the presence of energy dissipation, soliton velocity is bound from above due to the balance of the energy gain from the magnetic field, and its loss because of the dissipation and radiation of linear sound waves. This balance occurs at the resonant frequency of the magnetic field. It is concluded that such significant impact of time-depending magnetic field on charge transport, provided by solitons, can affect functioning of the devices based on low-dimensional moolecular systems. These results suggest the physical mechanism of therapeutic effects of oscillating magnetic fields.

cond-mat.soft↗

arXiv2024

Davydov's soliton in an external alternating magnetic field

The influence of an external oscillating in time magnetic field on the dynamics of the Davydov's soliton is investigated. It is shown that it essentially depends not only on the amplitude and frequency of the magnetic field, but also on the field orientation with respect to the molecular chain axis. The soliton velocity and phase are calculated. They are oscillating in time functions with the frequency of the main harmonic, given by the external field frequency, and higher multiple harmonics. It is concluded that such complex effects of external time-depending magnetic fields on the dynamics of solitons modify the charge transport in low-dimensional molecular systems, which can affect functioning of the devices based on such systems. These results suggest also the physical mechanism of therapeutic effects of oscillating magnetic fields, based on the field influence on the dynamics of solitons which provide charge transport through biological macro-molecules in the redox processes.

cond-mat.soft↗

arXiv2015

The working principle of magnetic resonance therapy

In this paper we describe briefly the basic aspects of magnetic resonance therapy, registered as TMR therapy. Clinical studies have shown that application of this therapy significantly accelerates wound healing and, in particular, healing of the diabetic foot disease. To understand the working principle of this therapy, we analyze relevant to it biological effects produced by magnetic fields. Based on these data, we show that there is a hierarchy of the possible physical mechanisms, which can produce such effects. The mutual interplay between the mechanisms can lead to a synergetic outcome delayed in time, which can affect the physiological state of the organism. In particular, we show that soliton mediated charge transport during the redox processes in living organisms is sensitive to magnetic fields, so that such fields can facilitate redox processes in particular, and can stimulate the healing effect of the organism in general. This and other non-thermal resonant mechanisms of the biological effects of magnetic fields are summarized as the working principle of the magnetic resonance therapy. We support our approach by some biological and histological data (both in vitro and in vivo) and, finally, by some clinical data.

physics.med-ph↗

arXiv2014

Biological effects of pulsating magnetic fields: role of solitons

In this paper, we analyze biological effects produced by magnetic fields in order to elucidate the physical mechanisms, which can produce them. We show that there is a chierarchy of such mechanisms and that the mutual interplay between them can result in the synergetic outcome. In particular, we analyze the biological effects of magnetic fields on soliton mediated charge transport in the redox processes in living organisms. Such solitons are described by nonlinear systems of equations and represent electrons that are self-trapped in alpha-helical polypeptides due to the moderately strong electron-lattice interaction. They represent a particular type of disssipativeless large polarons in low-dimensional systems. We show that the effective mass of solitons in the is different from the mass of free electrons, and that there is a resonant effect of the magnetic fields on the dynamics of solitons, and, hence, on charge transport that accompanies photosynthesis and respiration. These effects can result in non-thermal resonant effects of magnetic fields on redox processes in particular, and on the metabolism of the organism in general. This can explain physical mechanisms of therapies based on applying magnetic fields.

physics.bio-ph↗