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V. D. Lakhno

Publications and source records attributed to V. D. Lakhno.

32 records · Page 2Linked to original sources
arXiv2013

Hole Conductivity in Heterogeneous DNA Fragments

The characteristics of cation radical (hole) migration in heterogeneous DNA were investigated on the basis of Kubo formula, in which correlation functions were obtained from solutions of systems of Bogoliubov hierarchy. The cutting of Bogoliubov hierarchy was carried out by excepting correlations of the third and higher order. The obtained system of non-linear differential equations was investigated both analytically and numerically. The environment polarization, caused by interaction of holes with base pairs vibrations, was shown to play the key role in transport processes. The energy of the interaction can ten-fold exceed vibration energy. The transfer rate between adjacent DNA bases in one-dimensional case was shown to be almost independent of the nature and behavior of more distant pairs. The charge probability amplitude oscillates in the picosecond timescale. Nonetheless, the rates of hole transfer, obtained by averaging over these oscillations, turned out to be very close to the experimental data. The calculated dependence of the hole transfer rate between two guanine bases on the number of intervening adenine bases was also in good agreement with the experimental data. Besides, the temperature dependence of the transfer rate was investigated. Hopping mechanism was shown to make the main contribution to the hole transport process at 300 K.

cond-mat.other↗
arXiv2013

Formation of stationary electronic states in finite homogeneous molecular chains

Evolution of an arbitrary initial distribution of a quantummechanical particle in a uniform molecular chain is simulated by a system of coupled quantumclassical dynamical equations with dissipation. Stability of a uniform distribution of the particle over the chain is studied. An asymptotical expression is obtained for the time in which a localized state is formed. The validity of the expression is checked by direct computational experiments. It is shown that the time of soliton and multisoliton type states formation depends strongly on the initial phase of the particle's wave function. It is shown that in multisoliton states objects with a fractional electron charge which can be observed experimentally are realized. The results obtained are applied to synthetic uniform polynucleotide molecular chains.

cond-mat.other↗
arXiv2013

Translation invariant theory of polaron (bipolaron) and the problem of quantizing near the classical solution

A physical interpretation of translation-invariant polarons and bipolarons is presented, some results of their existence are discussed. Consideration is given to the problem of quantization in the vicinity of the classical solution in the quantum field theory. The lowest variational estimate is obtained for the bipolaron energy E(η) with E(0)=-0,440636α^2, where αis a constant of electron-phonon coupling, ηis a parameter of ion binding.

cond-mat.other↗
arXiv2013

Comments to a series of works by V.K. Mukhomorov on the theory of a continuum polaron and two-center bipolaron (axially symmetrical quasimolecular dimer)

Some critical remarks are made regarding a series of works by V.K. Mukhomorov dealing with polarons and oscillatory and rotational spectrum of a large-radius bipolaron near a subsidiary minimum corresponding to its two-center configuration. It is shown that V.K. Mukhomorov's conclusion that by varying the bipolaron functional one should look for a constrained rather than absolute minimum is erroneous. Consideration of interelectronic correlations corresponding to a direct dependence of the wave function of the studied system on the distance between the electrons does not break the virial theorem. In the strong coupling limit the virial theorem holds true for both one-center and two-center bipolaron states, the latter representing a subsidiary minimum which arises due to a choice of an insufficiently versatile variation function.

cond-mat.other↗
arXiv2013

Dynamics of Charge Transfer in Ordered and Chaotic Nucleotide Sequences

Charge transfer is considered in systems composed of a donor, an acceptor and bridge sites of (AT) nucleotide pairs. For a bridge consisting of 180 (AT) pairs, three cases are dealt with: a uniform case, when all the nucleotides in each strand are identical; an ordered case, when nucleotides in each DNA strand are arranged in an orderly fashion; a chaotic case, when (AT) and (TA) pairs are arranged randomly. It is shown that in all the cases a charge transfer from a donor to an acceptor can take place. All other factors being equal, the transfer is the most efficient in the uniform case, the ordered and chaotic cases are less and the least efficient, accordingly. The results obtained are in agreement with experimental data on long-range charge transfer in DNA.

physics.bio-ph↗
arXiv2013

On the Possibility of Superfast Charge Transfer in DNA

Numerous experiments on charge transfer in DNA yield a contradictory picture of the transfer: on the one hand they suggest that it is a very slow process and the charge is almost completely localized on one Watson-Crick pair, but on the other hand they demonstrate that the charge can travel a very large distance. To explain this contradiction we propose that superfast charge transitions are possible between base pairs on individual DNA fragments resulting in the establishment of a quasi-equilibrium charge distribution during the time less than that of charge solvation. In other words, we hypothesize these states irrespective of the nature of a mechanism responsible for their establishment, whether it be a hopping mechanism, or a band mechanism, or superexchange, or polaron transport, etc., leaving aside the debates of which one is more advantageous. We discuss qualitative differences between the charge transfer in a dry DNA and that in a solution. In a solution, of great importance is the charge solvation which decreases the transfer rate $10^7 - 10^8$ times as compared with a dry DNA. We consider the conditions under which the superfast charge transfer in a DNA leading to quasi-equilibrium distributions of polarons in a duplex is possible. Comparison of calculated quasi-equilibrium distributions with the experiment testifies to the possibility of superfast tunnel transitions of a hole in a DNA duplex in a solution.

physics.bio-ph↗
arXiv2013

On the possibility of electronic DNA nanobiochips

We have considered as a theoretical possibility for the development of a nanobiochip the operation principle of which is based on measuring conductance in single-stranded and double-stranded DNA. Calculations have demonstrated that in the majority of cases the conductance of double-stranded nucleotides considerably exceeds that of single-stranded ones. The results obtained are in agreement with recent experiments on measuring the oligonucleotide conductance. It has been shown that an electronic biochip containing 11 nucleotide pairs will recognize approximately 97% sequences. It has also been demonstrated that the percentage of identifiable sequences will grow with the sequence length.

physics.bio-ph↗
arXiv2013

Bloch oscillations of a soliton in a molecular chain

The paper presents results of numerical experiments simulating Bloch oscillations of solitons in a deformable molecular chain in a constant electric field. By the example of a homogeneous polynucleotide chain it is shown that the system under consideration can demonstrate complicated dynamical regimes when at the field intensities less than a certain critical value, a soliton as a whole exhibits oscillations, while at the field intensities exceeding the threshold, a soliton turns to a breather which oscillates. It is shown that the motion of a charge in a deformable chain is infinite as contrasted to that in a rigid chain.

cond-mat.mes-hall↗
arXiv2013

Electron motion in a Holstein molecular chain in an electric field

A charge motion in an electric field in a Holstein molecular chain is modeled in the absence of dissipation. It is shown that in a weak electric field a Holstein polaron moves uniformly experiencing small oscillations of its shape. These oscillations are associated with the chain's discreteness and caused by the presence of Peierls-Nabarro potential there. The critical value of the electric field intensity at which the moving polaron starts oscillating at Bloch frequency is found. It is shown that the polaron can demonstrate Bloch oscillations retaining its shape. It is also shown that a breathing mode of Bloch oscillations can arise. In all cases the polaron motion along the chain is infinite.

cond-mat.mes-hall↗
arXiv2013

A new approach to microscopic modeling of a hole transfer in heteropolymer DNA

Thermal oscillations of base pairs in the Peyrard-Bishop-Holstein model are simulated by stochastic fluctuations of base overlap integrals. Numerical investigation of the model is carried out for a hole transfer in $G_1A_2G_3G_4$ sequence which was previously studied experimentally by F. Lewis et al. A hole migration between $G_1$ and $G_3G_4$ is determined by the matrix elements of the charge transition, but presence and amplitude of their stochastic fluctuations proved to play a key role in reproduction of the experimental kinetics. Good agreement with the experimental data was obtained for a wide range of the model parameters' combinations.

physics.chem-ph↗
arXiv2013

Possibility of a (bi)polaron high-temperature superconductivity in Poly A/ Poly T DNA duplexes

Dynamical equations for a polaron and bipolaron in a DNA duplex are obtained on the basis of Holstein-Hubbard Hamiltonian. It is shown that in a PolyA/PolyT duplex especially stable is a bipolaron state in which holes are localized on different chains of the duplex. With the use of the polaron and bipolaron free energy, the temperature of bipolaron decay is found to be T_d \approx 350 K which can serve as an approximate estimate of the superconducting transition temperature. The way of constructing superconducting nanowires on the basis of DNA is suggested.

cond-mat.supr-con↗
arXiv2013

Translation-invariant bipolarons and the problem of high-temperature superconductivity

It is shown that the bipolaron ground state is described by a delocalized wave function. For a two-parameter wave function, the lowest variation estimate of the ground state energy in the strong coupling limit is found to be $E=- 0,414125 α^2$. This is much lower than that derived with the use of the localized bipolaron wave function. The results obtained testify to the possibility of a bipolaron mechanism of high-temperature superconductivity.

cond-mat.str-el↗
arXiv2012

On the cutoff parameter in the translation-invariant theory of the strong coupling polaron. (response to comments [arXiv:1204.4142] on the paper V. D. Lakhno, SSC, 152, (2012), 621)

The paper is a reply to the arguments adduced by the authors of Ref. [arXiv:1204.4142] against the results obtained by the author in Refs. [6,7]. It is shown that these arguments are based on the erroneous approach made in Ref. [arXiv:1204.4142] to the strong coupling limit when the cutoff parameter is introduced in the theory.

cond-mat.other↗