Search results for: quantum dynamics

Dynamics of quantum entanglement
PublicationA model of discrete dynamics of entanglement of a bipartite quantum state is considered. It involves a global unitary dynamics of the system and periodic actions of local bistochastic or decaying channel. For initially pure states the decay of entanglement is accompanied by an increase of von Neumann entropy of the system. We observe and discuss revivals of entanglement due to unitary interaction of subsystems. For some mixed states...

Quantum corrections to 4 model solutions and applications to Heisenberg chain dynamics
PublicationThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the onedimensional φ^4 model within the correspondent physics are valuated with account of rest d − 1 dimensions of a ddimensional theory. A quantization of the model is considered in terms of space time functional integral. The generalized zetafunction formalism is used to renormalize and evaluate the functional...

Beyond the helium buffer: 12C−2 rotational cooling in cold traps with H2 as a partner gas: interaction forces and quantum dynamics
Publicationabstract = { The scattering crosssections and corresponding rate coefficients for rotationally inelastic collisions of $^{12}$C$_2$^$ ($^2 \Sigma_g^+$) with H$_2$ ($^1 \Sigma_g^+$) are presented over a broad range of coldtrap temperatures. They have been calculated using quantum scattering theory that employs a new ab initio potential energy surface. The rate coefficients for the inelastic processes in the anionic partner are...

Quantum corrections to phi^4 model solutions and applications to Heisenberg chain dynamics
PublicationThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the onedimensional φ^4 model within the correspondent physics are evaluated with account of rest d−1 dimensions of a ddimensional theory. A quantization of the model is considered in terms of spacetime functional integral. The generalized zetafunction formalism is used to renormalize and evaluate the functional integral...

Lowenergy positron scattering from gasphase tetrahydrofuran: A quantum treatment of the dynamics and a comparison with experiments
PublicationIn this paper we report new quantum calculations of the dynamics for lowenergy positrons interacting with gaseous molecules of tetrahydrofuran. The new quantum scattering cross sections are differential and integral cross sections at collision energies between 1.0 and 25.0 eV and include a careful treatment of the additional effects on the scattering process brought about by the permanent dipole moment of the target molecule....

Lowenergy positron scattering from gasphase pyrimidine: A quantum treatment of the dynamics and a comparison with experiments
PublicationWe are reporting detailed quantum scattering calculations that describe the diffusion of a beam of lowenergy positrons interacting with the pyrimidine target as a gasphase partner. The calculations have employed an essentially ab initio model for the shortrange correlation interaction and for the electrostatic interaction of an impinging positron and the electron+nuclear structure of the target molecule at its equilibrium geometry.

Toward mechanosynthesis of diamondoid sructures: viii. quantumchemical molecular dynamics simulations of hexagonal siliconiv structure synthesis with stm
Publicationw tej publikacji badano metodami kwantowochemicznymi różne strategie mechanosyntezy heksagonalnego krzemu iv. określono przybliżone warunki mechanosyntezy krzemu w formie lonsdaleitu za pomocą uhvspm.

An insight into the mixed quantum mechanicalmolecular dynamics simulation of a ZnIICurcumin complex with a chosen DNA sequence that supports experimental DNA binding investigations
PublicationAn important aspect of research pertaining to Curcumin (HCur) is the need to arrest its degradation in aqueous solution and in biological milieu. This may be achieved through complex formation with metal ions. For this reason, a complex of HCur was prepared with ZnII, that is not likely to be active in redox pathways, minimizing further complications. The complex is monomeric, tetrahedral, with one HCur, an acetate and a molecule...

Toward Mechanosynthesis of Diamondoid Structures: VI. QuantumChemical Molecular Dynamics Comparison of Conditions for the STM Tip Driven Mechanosynthesis on Hydrogenated Si(111), Si(110) and Si(100) Surfaces.
Publicationmożliwość prototypowania przejściowych generacji nanourządzeń otrzymanych drogą pozycjonowanej mechanosyntezy za pomocą stm wyposażonego w ostrze typu swcnt są analizowane metodą kwantowochemicznej dynamiki molekularnej. proponowana strategia syntezy polega na insercji atomów si oraz cząsteczek sih2 we wiązania sih na uwodornionej powierzchni si(111), si(110) oraz si(100) kryształu krzemu. rezultaty modelowania sugerują, że...

DYNAMICOL Ultrafast Charge Transfer in ion atom collision investigated by Molecular Quantum Dynamics Methods
ProjectsProject realized in Faculty of Applied Physics and Mathematics according to PERG08GA2010277201 agreement from 20110222

Jan Kozicki dr hab. inż. arch.
PeopleIn year 2002 after obtaining master's degree in construction was employed on Faculty of Civil and Environmental Engineering. In 2004 obtained master's degree in architecture on Faculty of Architecture focusing on a research outpost on Mars. Defended PhD in year 2007 in the field of numerical modeling. In 2013 obtained Licentiate degree in theoretical physics on University of Gdańsk. In year 2014 obtained habilitation in technical...

CosmicTime Quantum Mechanics and the PassageofTime Problem
PublicationA new dynamical paradigm merging quantum dynamics with cosmology is discussed.

Optimization of the femtosecond laser impulse for excitation and the spinorbitmediated dissociation in the NaRb molecule
Open Research DataHigh accuracy ab initio potential energy curves (1tSigma+, 2sSigma+, 1tPi), electronic transition dipole moment function (1tSigma+  1tPi), and spinorbit coupling (2sSigma+  1tPi) have been calculated for the NaRb molecule. The timedependent excitation and dissociation processes in the polar alkali diatomic NaRb molecule and the quantum properties...

Generic emergence of classical features in quantum Darwinism
PublicationQuantum Darwinism posits that only specific information about a quantum system that is redundantly proliferated to many parts of its environment becomes accessible and objective, leading to the emergence of classical reality. However, it is not clear under what conditions this mechanism holds true. Here we prove that the emergence of classical features along the lines of quantum Darwinism is a general feature of any quantum dynamics:...

Dynamical description of quantum computing: generic nonlocality of quantumnoise
PublicationWe develop a dynamical nonMarkovian description of quantum computing in the weakcoupling limit, in the lowestorder approximation. We show that the longrange memory of the quantum reservoir (such as the 1/t4 one exhibited by electromagnetic vacuum) produces a strong interrelation between the structure of noise and the quantum algorithm, implying nonlocal attacks of noise. This shows that the implicit assumption of quantum error...

Quantum structure in competing lizard communities
PublicationAlmost two decades of research on applications of the mathematical formalism of quantum theory as a modeling tool in domains different from the microworld has given rise to many successful applications in situations related to human behavior and thought, more specifically in cognitive processes of decisionmaking and the ways concepts are combined into sentences. In this article, we extend this approach to animal behavior, showing...

Hybrid quantumclassical approach for atomistic simulation of metallic systems
PublicationThe learnonthefly (LOTF) method [G. Csanyi et al., Phys. Rev. Lett. 93, 175503 (2004)] serves to seamlessly embed quantummechanical computations within a moleculardynamics framework by continual local retuning of the potential's parameters so that it reproduces the quantummechanical forces. In its current formulation, it is suitable for systems where the interaction is shortranged, such as covalently bonded semiconductors....

A dipoledriven path for electron and positron attachments to gasphase uracil and pyrimidine molecules: a quantum scattering analysis
PublicationElectron and positron scattering processes in the gasphase are analysed for uracil and pyrimidine molecules using a multichannel quantum approach at energies close to threshold. The special effects on the scattering dynamics induced by the large dipole moments in both molecules on the spatial features of the continuum leptonic wavefunctions are here linked to the possible bound states of the Rydberglike molecular anions or ‘positroned’...

Marek Czachor prof. dr hab.
People 
Numerical modeling of quantum dynamical processes
PublicationIn this dissertation I present a highprecision (15, 18 or 33 decimal places) C++ implementation of quantum dynamics time propagation algorithms for both timeindependent and timedependent Hamiltonian with an inhomogeneous source term. Moreover I present an extension of both algorithms for time propagation to handle arbitrary number of coupled electronic levels. I have performed a careful validation of these implementations comparing...

Rotational statechanging collisions of C2H− and C2N− anions with He under interstellar and cold ion trap conditions: A computational comparison
PublicationWe present an extensive range of quantum calculations for the statechanging rotational dynamics involving two simple molecular anions that are expected to play some role in the evolutionary analysis of chemical networks in the interstellar environments, C2H− (X1Σ+) and C2N− (X3Σ−), but for which inelastic rates are only known for C2H−. The same systems are also of direct interest in modeling selective photodetachment experiments...

Objectivity in the nonMarkovian spinboson model
PublicationObjectivity constitutes one of the main features of the macroscopic classical world. An important aspect of the quantumtoclassical transition issue is to explain how such a property arises from the microscopic quantum theory. Recently, within the framework of open quantum systems, there has been proposed such a mechanism in terms of the socalled spectrum broadcast structures. These are multipartite quantum states of the system...

The spontaneous electron emission and rotational predissociation lifetimes of the diatomic silver anion
Open Research DataThe process of a twochannel decay of the diatomic silver anion (Ag2), namely the spontaneous electron ejection giving Ag2 + e and the dissociation leading to Ag + Ag is theoretically studied. The ground state potential energy curves (PECs) of the neutral silver dimer and anionic silver diatomic molecule are calculated using the single reference...

The rovibrational energy levels of the diatomic silver anion and neutral silver dimer
Open Research DataThe process of a twochannel decay of the diatomic silver anion (Ag2), namely the spontaneous electron ejection giving Ag2 + e and the dissociation leading to Ag + Ag is theoretically studied. The ground state potential energy curves (PECs) of the neutral silver dimer and anionic silver diatomic molecule are calculated using the single reference...

At the Limits of CriticalityBased Quantum Metrology: Apparent SuperHeisenberg Scaling Revisited
PublicationWe address the question of whether the superHeisenberg scaling for quantum estimation is indeed realizable. We unify the results of two approaches. In the first one, the original system is compared with its copy rotated by the parameterdependent dynamics. If the parameter is coupled to the onebody part of the Hamiltonian, the precision of its estimation is known to scale at most as N−1 (Heisenberg scaling) in terms of the number...

Quantumclassical calculations of the nanomechanical properties of metals
PublicationTradycyjnie symulacje komputerowe układów w skali atomowej prowadzone są przy użyciu klasycznej metody dynamiki molekularnej (MD) bądź kwantowych metod ab initio. Główną wadą ujęcia klasycznego jest jego empiryczna natura, a co za tym idzie  niewielka przenośność, jego prostota natomiast pozwala na przeprowadzanie symulacji układów zawierających miliony atomów. W wyniku zastosowania metod kwantowych otrzymuje się bardziej wiarygodne...

Catalytic Mechanism of NonTarget DNA Cleavage in CRISPRCas9 Revealed by Ab Initio Molecular Dynamics
PublicationCRISPRCas9 is a cuttingedge genome editing technology, which uses the endonuclease Cas9 to introduce mutations at desired sites of the genome. This revolutionary tool is promising to treat a myriad of human genetic diseases. Nevertheless, the molecular basis of DNA cleavage, which is a fundamental step for genome editing, has not been established. Here, quantum–classical molecular dynamics (MD) and free energy methods are used...

Refined theoretical study of radiative association: Cross sections and rate constants for the formation of SiN
PublicationRadiative association of silicon mononitride (SiN) in its two lowest molecular electronic states is studied through quantum and classical dynamics. Special attention is paid to the behavior of the cross section at high collision energies. A modified expression for the semiclassical cross section is presented which excludes transitions to continuum states. This gives improved agreement with quantum mechanical perturbation theory...

Intramolecular transformation of an antifungal antibiotic nystatin A1 into its isomer, isonystatin A1  structural and molecular modeling studies
PublicationNystatin A1, a polyene macrolide antifungal antibiotic, in a slightly basic or acidic solution undergoes an intramolecular transformation, yielding a structural isomer, the translactonization product, isonystatin A1 with lactone ring diminished by two carbon atoms. Structural evidence is provided by advanced NMR and Mass Spectrometry (MS) studies. Molecular dynamics simulations and quantum mechanics calculations gave the insight...

Automatic Regularization by Quantization in Reducible Representations of CCR: PointForm Quantum Optics with Classical Sources
PublicationElectromagnetic fields are quantized in a manifestly covariant way by means ofa class of reducible "centerofmass Nrepresentations" of the algebra of canonical commutationrelations (CCR). The fourpotential Aa(x) transforms in these representations as aHermitian fourvector field in Minkowski fourposition space (without change of gauge), butin momentum space it splits into spin1 massless photons and two massless scalars. Whatwe...

Wavepacket of the Universe and its Spreading
PublicationWavepackets in quantum mechanics spread and the Universe in cosmology expands. We discuss a formalism where the two effects can be unified. The basic assumption is that the Universe is determined by a unitarily evolving wavepacket defined on spacetime. Spacetime is static but the Universe is dynamic. Spreading analogous to expansion known from observational cosmology is obtained if one regards time evolution as a dynamical process...

Vibrational excitation of acetylene by positron impact
PublicationVibrationally inelastic quantum calculations are carried out at low collision energies for the scattering of a beam of positrons off acetylene gaseous molecules. The normal mode analysis is assumed to be valid and the relative fluxes into the C–C and C–H symmetric vibrational modes are computed within a BodyFixed (BF) formulation of the dynamics by solving the relevant vibrational Coupled Channels (VCC) equations. The clear dominance...

Autocorrelation function for the chosen effective potential of the diatomic silver anion
Open Research DataThe process of a twochannel decay of the diatomic silver anion (Ag2), namely the spontaneous electron ejection giving Ag2 + e and the dissociation leading to Ag + Ag is theoretically studied. The ground state potential energy curves (PECs) of the neutral silver dimer and anionic silver diatomic molecule are calculated using the single reference...

NonPerfect Propagation of Information to a Noisy Environment with SelfEvolution
PublicationWe study the nonperfect propagation of information for evolving a lowdimensional environment that includes selfevolution as well as noisy initial states and analyse the interrelations between the degree of objectivization and environment parameters. In particular, we consider an analytical model of three interacting qubits and derive its objectivity parameters. The numerical analysis shows that the quality of the spectrum broadcast...

Two examples of Quantum Dynamical Semigroups
PublicationThe Hamiltonians of the considered bipartite systems are of the form $$ H_{S,R} = H_S /times 1_R + Q_{S} /times M_R + 1_S /times H_R $$ Subindex $S$ corresponds to the observed system and $R$ to the reservoir (the enviroment of $S$). Two classes of systems are distinguished: the discretecontinuous...

Interactions of telomeric proteins with nucleic acids: sequence recognition on intact and oxidatively damaged telomeres
PublicationTelomeres are complex nucleoprotein assemblies that play a vital role in the maintenance of functional ends of linear chromosomes. Telomeric DNA, composed of tandem repeats of the 5'TTAGGG3' motif, solves the socalled end replication problem: as chromosomes shorten with each cell division, no information is lost, and the telomere can be reextended. In the cell, many protein factors regulate telomere length, nuclear positioning...

Computational methods for calculation of binding free energy for ligandreceptor complexes
PublicationAccurate description of the molecular complexes energetic influence is required for understanding of many biological functions carried out by proteins. Therefore, estimation of binding free energy for ligandreceptor complexes is of highest importance for structurebased ligand design and drug discovery approaches.Experimental methods of determination of difference in Gibbs'es free energy have many limitations. Thus, computational...

Spontaneous electron emission vs dissociation in internally hot silver dimer anions
PublicationReferring to a recent experiment, we theoretically study the process of a twochannel decay of the diatomic silver anion (Ag2), namely the spontaneous electron ejection giving Ag2 + e and the dissociation leading to Ag + Ag. The ground state potential energy curves of the silver molecules of diatomic neutral and negative ion were calculated using proper pseudopotentials and atomic basis sets. We also estimated the nonadiabatic...

Redundant information encoding in QED during decoherence
PublicationBroadly understood decoherence processes in quantum electrodynamics, induced by neglecting either the radiation [L. Landau, Z. Phys. 45, 430 (1927)] or the charged matter [N. Bohr and L. Rosenfeld, K. Danske Vidensk. Selsk, Math.Fys. Medd. XII, 8 (1933)], have been studied from the dawn of the theory. However, what happens in between, when a part of the radiation may be observed, as is the case in many reallife situations, has...

Evaluating experimental molecular physics studies of radiation damage in DNA*
PublicationThe field of Atomic and Molecular Physics (AMP) is a mature field exploring the spectroscopy, excitation, ionisation of atoms and molecules in all three phases. Understanding of the spectroscopy and collisional dynamics of AMP has been fundamental to the development and application of quantum mechanics and is applied across a broad range of disparate disciplines including atmospheric sciences, astrochemistry, combustion and environmental...

Nonadiabatic coupling elements between the diatomic silver anion and neutral silver dimer plus continuum electron
Open Research DataThe process of a twochannel decay of the diatomic silver anion (Ag2), namely the spontaneous electron ejection giving Ag2 + e and the dissociation leading to Ag + Ag is theoretically studied. The ground state potential energy curves (PECs) of the neutral silver dimer and anionic silver diatomic molecule are calculated using the single reference...

Why Are LeftHanded GQuadruplexes Scarce?
PublicationGquadruplexes (G4s) are nucleic acid structures crucial for the regulation of gene expression and genome maintenance. While they hold promise as nanodevice components, achieving desired G4 folds requires understanding the interplay between stability and structural properties, like helicity. Although righthanded G4 structures dominate the experimental data, the molecular basis for this preference over lefthanded helicity is unclear....

The Role of Electrostatics in Enzymes: Do Biomolecular Force Fields Reflect Protein Electric Fields?
PublicationPreorganization of large, directionally oriented, electric fields inside protein active sites has been proposed as a crucial contributor to catalytic mechanism in many enzymes, and it may be efficiently investigated at the atomistic level with molecular dynamics simulations. Here, we evaluate the ability of the AMOEBA polarizable force field, as well as the additive Amber ff14SB and Charmm C36m models, to describe the electric...

Mechanism of reaction of RNAdependent RNA polymerase from SARSCoV2
PublicationWe combine molecular dynamics, statistical mechanics, and hybrid quantum mechanics/molecular mechanics simulations to describe mechanistically the severe acute respiratory syndrome coronavirus 2 (SARSCoV2) RNAdependent RNA polymerase (RdRp). Our study analyzes the binding mode of both natural triphosphate substrates as well as remdesivir triphosphate (the active form of drug), which is bound preferentially over ATP by RdRp while...

Principles of target DNA cleavage and the role of Mg2+ in the catalysis of CRISPR–Cas9
PublicationAt the core of the CRISPR–Cas9 genomeediting technology, the endonuclease Cas9 introduces sitespecific breaks in DNA. However, precise mechanistic information to ameliorate Cas9 function is still missing. Here, multimicrosecond molecular dynamics, free energy and multiscale simulations are combined with solution NMR and DNA cleavage experiments to resolve the catalytic mechanism of target DNA cleavage. We show that the conformation...

Statistical properties of a modified standard map in quantum and classical regimes
PublicationWe present a model—a modified standard map. This model has interesting properties that allow quantum–classical correspondences to be studied. For some range of parameters in the classical phase space of this model, there exist large accelerator modes. We can create a family of maps that have large accelerator modes.

Decoherencefree communication over multiaccess quantum channels
PublicationIn this paper we consider decoherencefree communication over multiple access and kuser quantum channels. First, we concentrate on a hermitian unitary noise model U for a twoaccess biunitary channel and show that in this case a decoherencefree code exists if the space of Schmidt matrices of an eigensubspace of U exhibits certain properties of decomposability. Then, we show that our technique is also applicable for generic random unitary...

Guanosine Dianions Hydrated by One to Four Water Molecules
PublicationIntermolecular interactions such as those present in molecule···water complexes may profoundly influence the physicochemical properties of molecules. Here, we carried out an experimental–computational study on doubly deprotonated guanosine monophosphate···water clusters, [dGMP – 2H]2–·nH2O (n = 1–4), using a combination of negative anion photoelectron spectroscopy (NIPES) with molecular dynamics (MD) and quantum chemical (QM) calculations....

Mixed, quantumclassical description of electron density transfer in the collision process
PublicationIn this work, we investigate an ionatom model describing the timedependent evolution of electron density during the collision. For a $S^{3+} H$ system, numerical simulations are based on classical trajectory calculations, and the electron density behaviour is described with the timedependent Schr\"odinger equation. We apply the finite difference method to obtain quantitative insights into the charge transfer dynamics, providing...

LaserInduced Graphitization of Polydopamine on Titania Nanotubes
PublicationSince the discovery of laserinduced graphite/graphene, there has been a notable surge of scientific interest in advancing diverse methodologies for their synthesis and applications. This study focuses on the utilization of a pulsed Nd:YAG laser to achieve graphitization of polydopamine (PDA) deposited on the surface of titania nanotubes. The partial graphitization is corroborated through Raman and XPS spectroscopies and supported...