A5064644308- Nuclear physics research studies
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Quantum and electron transport phenomena
- Molecular Junctions and Nanostructures
- Quantum Chromodynamics and Particle Interactions
- Atomic and Molecular Physics
- Quantum chaos and dynamical systems
- Astrophysics and Cosmic Phenomena
- Astronomical and nuclear sciences
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- High-pressure geophysics and materials
- Pulsars and Gravitational Waves Research
- Semiconductor Quantum Structures and Devices
- High-Energy Particle Collisions Research
- Physics of Superconductivity and Magnetism
- Particle accelerators and beam dynamics
- Spectroscopy and Quantum Chemical Studies
- Graphene research and applications
- Quantum Mechanics and Non-Hermitian Physics
- Advanced NMR Techniques and Applications
- Gamma-ray bursts and supernovae
Joint Institute for Nuclear Research
2009-2023
Université Libre de Bruxelles
2011-2013
Dubna State University
2004
Lomonosov Moscow State University
2000-2001
We discuss the use of super-fermion formalism to represent and solve quantum kinetic equations for electron transport problem. Starting with Lindblad master equation molecule connected two metal electrodes, we convert problem finding nonequilibrium steady state many-body non-Hermitian Liouvillian in super-Fock space. transform normal ordered form, introduce quasiparticles by a set canonical nonunitary transformations develop general theory through interacting region. The approach is applied...
We investigate the impact of charged-current--neutrino processes on formation and evolution neutrino spectra during deleptonization proto-neutron stars. To this end we develop full kinematics these reaction rates consistent with nuclear equation state, including weak magnetism contributions. This allows us to systematically study inelastic contributions ${\ensuremath{\nu}}_{e}$ ${\overline{\ensuremath{\nu}}}_{e}$ luminosities average energies. Furthermore, explore role inverse neutron decay,...
In this paper, we present results of the second experiment on synthesis Mc isotopes in $^{243}\mathrm{Am}+^{48}\mathrm{Ca}$ reaction performed at gas-filled separator DGFRS-2 SHE Factory JINR. The new isotope $^{286}\mathrm{Mc}$ was synthesized, and its half-life $20\begin{array}{c}+98\\ \ensuremath{-}9\end{array}$ ms \ensuremath{\alpha}-particle energy $10.71\ifmmode\pm\else\textpm\fi{}0.02$ MeV were determined. A $^{286}\mathrm{Mc} \ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{decay}$...
We propose a new method to calculate stellar weak-interaction rates. It is based on the Thermo-Field-Dynamics formalism and allows calculation of response nuclei at finite temperatures. The thermal evolution GT$_+$ distributions presented for sample $^{54, 56}$Fe ~$^{76,78,80}$Ge. For Ge we also strength distribution first-forbidden transitions. show that effects shift centroid lower excitation energies make possible negative- low-energy In our model demonstrate unblocking effect transitions...
We discuss the use of tunneling electron current to control and catalyze chemical reactions. Assuming separation time scales for electronic nuclear dynamics we employ Langevin equation a reaction coordinate. The contains nonconservative current-induced forces gives nonequilibrium, effective potential energy surface current-carrying molecular systems. are computed via Keldysh nonequilibrium Green's functions. Once current-depended is defined, modeled as an escape Brownian particle from well....
We have calculated electron capture rates for neutron-rich $N=50$ nuclei ($^{78}$Ni, $^{82}$Ge, $^{86}$Kr, $^{88}$Sr) within the Thermal QRPA approach at temperatures $T=0$, corresponding to on ground-state, and $T=10$ GK (0.86 MeV), which is a typical temperature are abundant during supernova collapse. In agreement with recent experiments, we find no Gamow-Teller (GT$_+$) strength low excitation energies, $E<7$ MeV, caused by Pauli blocking induced shell gap. At astrophysically relevant...
We present a method to perform stability analysis of nonequilibrium fixed points appearing in self-consistent electron transport calculations. The are given by the solution stationary, nonlinear kinetic equation for single-particle density matrix. obtain matrix linearizing around and analyze real part its spectrum assess asymptotic time behavior points. derive expressions matrices within Hartree-Fock linear response adiabatic time-dependent functional theory. multiple is performed...
We present an escape rate theory for current-induced chemical reactions. use Keldysh nonequilibrium Green's functions to derive a Langevin equation the reaction coordinate. Due out of equilibrium electronic degrees freedom, friction, noise, and effective temperature in depend locally on As example, we consider dissociation diatomic molecules induced by current from scanning tunnelling microscope tip. In resonant regime, molecular involves two processes which are intricately interconnected:...
The thermal quasiparticle random-phase approximation is combined with the Skyrme energy density functional method (Skyrme-TQRPA) to study response of a hot nucleus an external perturbation. For sample nuclei $^{56}\mathrm{Fe}$ and $^{82}\mathrm{Ge}$, Skyrme-TQRPA applied analyze effects on strength function charge-neutral Gamow--Teller transitions, which dominate neutrino-nucleus reactions at ${E}_{\ensuremath{\nu}}\ensuremath{\lesssim}20$ MeV. relevant supernova temperatures we calculate...
We use a superoperator representation of the quantum kinetic equation to develop nonequilibrium perturbation theory for an inelastic electron current through dot. derive Lindblad-type embedded dot (i.e. connected Lindblad dissipators buffer zone). The is converted non-Hermitian field in Liouville-Fock space. general many-body developed and applied with electron-vibronic electron-electron interactions. Our becomes equivalent Keldysh Green's function perturbative treatment provided that zone...
We study inelastic neutrino scattering off hot nuclei for temperatures relevant under supernova conditions. The method we use is based on the quasiparticle random phase approximation extended to finite within thermo field dynamics (TQRPA). allows a transparent treatment of upward and downward transitions in nuclei, avoiding application Brink's hypothesis. For sample $^{56}$Fe $^{82}$Ge perform detailed analysis thermal effects strength distributions allowed Gamow-Teller (GT) which dominate...
Based on the super-fermion representation of quantum kinetic equations we develop nonequilibrium, post-Hartree–Fock many-body perturbation theory for current through a region interacting electrons. We apply to out equilibrium Anderson model and discuss practical implementation approach. Our calculations show that nonequilibrium electronic correlations may produce significant quantitative qualitative corrections mean-field transport properties.
We present a new approach to treat correlations in nonequilibrium quantum many-particle system. The method is based on ideas of configuration interaction theory exact nonperturbative ground state electronic structure calculations. use superoperator techniques Liouville–Fock space and represent the density matrix as linear combination all possible quasiparticle excitations built appropriate reference state. As an example we consider electron transport through system with electron–phonon...
A microscopic thermodynamically consistent approach is applied to compute electron capture (EC) rates and cross sections on nuclei in hot stellar environments. The section calculations are based the Donnelly-Walecka multipole expansion method for treatment of semi-leptonic processes nuclei. To take into account thermal effects, we express terms temperature- momentum-dependent spectral functions respective charge-changing operators. computed by employing self-consistent quasiparticle RPA...
We develop a superoperator coupled cluster method for nonequilibrium open many-body quantum systems described by the Lindblad master equation. The is universal and applicable to of interacting fermions, bosons or their mixtures. present general theory consider its application problem transport through system with electron-phonon correlations. results are assessed against perturbation configuration interaction calculations.
Using the thermal quasiparticle random phase approximation, we study process of neutrino and antineutrino capture on hot nuclei in supernova environments. For sample $^{56}$Fe $^{82}$Ge perform a detailed analysis effects strength distribution allowed Gamow-Teller transitions which dominate low-energy charged-current reactions. The finite temperature cross sections are calculated taking into account contributions both forbidden transitions. enhancement is explained by considering GT$_\pm$...
Neutrino nuclear scattering in hot and dense matter relevant for supernovae, neutron star mergers, proto-neutron stars is considered. At finite temperature, neutrinos exhibit exo- endoenergetic on species due to the neutral-current Gamow-Teller interaction component. From an analysis of energy transfer straggling cross sections we demonstrate that additional noticeable mechanisms equilibrating with originate magnetized nucleon gas. Average transfer, i.e., ratio sections, depends almost...
We consider a single molecule circuit embedded into solvent. The Born dielectric solvation model is combined with Keldysh nonequilibrium Green's functions to describe the electron transport properties of system. Depending on constant, solvent induces multiple steady states corresponding hysteresis in molecular current-voltage characteristics as well negative differential resistance. identify physical range and parameters where effects are present. position resistance peak can be controlled...
The approach in a theory of collective excitations hot nuclei exploring the formalism thermo field dynamics and model Hamiltonian consisting mean field, BCS paring interaction long-range particle-hole effective forces is reexamined. In contrast with earlier studies it found that wave function thermal phonon depended not only on Fermi-Dirac occupation numbers Bogoliubov quasiparticles but Bose as well. This strongly affects couplings due to renormalizing phonon-phonon enlarging number...
An extended Holstein-Primakoff mapping which incorporates both single- and double-fermion mappings is used in the context of thermofield dynamics to study next-to-leading order $1∕N$ expansion at finite temperature. For Lipkin-Meshkov-Glick model it shown that naturally leads correct Fermi statistics leading order.
The first excited level of 96Mo was investigated in a high-statistics experiment using the 95Mo(n, γγ) cold neutron capture reaction. measurements used high flux from research reactor at Institut Laue-Langevin and employed highly-efficient EXILL array to detect γ-ray coincidences. recorded statistics allow identification decay branches with only small relative intensity including E3 decay. With knowledge newly measured branching ratio known transition probability, lifetime determined and,...