ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTime-dependent quantum-mechanical methods for molecular dynamicsRonnie KosloffCite this: J. Phys. Chem. 1988, 92, 8, 2087–2100Publication Date (Print):April 1, 1988Publication History Published online1 May 2002Published inissue 1 April 1988https://pubs.acs.org/doi/10.1021/j100319a003https://doi.org/10.1021/j100319a003research-articleACS PublicationsRequest reuse permissionsArticle Views4161Altmetric-Citations1617LEARN ABOUT THESE METRICSArticle...

A new propagation scheme for the time dependent Schrödinger equation is based on a Chebychev polynomial expansion of evolution operator Û=exp(−iĤt). Combined with Fourier method calculating Hamiltonian operation not only extremely accurate but up to six times more efficient than presently used second order differencing scheme.

One of the nagging problems which arises in application discrete solution methods for wave‐propagation calculations is presence reflections or wraparound from boundaries numerical mesh. These undesired events eventually override actual seismic signals propagate modeled region. The to avoiding boundary effects used be enlarge mesh, thus delaying side and longer than range times involved modeling. Obviously this considerably increases expense computation. More recently, nonreflecting...

Quantum thermodynamics addresses the emergence of thermodynamical laws from quantum mechanics. The link is based on intimate connection with theory open systems. mechanics inserts dynamics into giving a sound foundation to finite-time-thermodynamics. 0-law I-law II-law and III-law considerations presented. emphasis consistence between two theories which address same subject different foundations. We claim that inconsistency result faulty analysis pointing flaws in approximations.

It is control that turns scientific knowledge into useful technology: in physics and engineering it provides a systematic way for driving dynamical system from given initial state desired target with minimized expenditure of energy resources. As one the cornerstones enabling quantum technologies, optimal keeps evolving expanding areas as diverse quantum-enhanced sensing, manipulation single spins, photons, or atoms, optical spectroscopy, photochemistry, magnetic resonance (spectroscopy well...

We present a novel approach to the control of selectivity reaction products. The central idea is that in two-photon or multiphoton process resonant with an excited electronic state, state potential energy surface can be used assist chemistry on ground surface. By controlling delay between pair ultrashort (femtosecond) laser pulses, it possible propagation time Different times, turn, generate different chemical There are many cases for which product formation should using this scheme....

Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution have already been profoundly affected by the application existing ...Read More

Quantum heat engines (QHE) are thermal machines where the working substance is quantum. In extreme case medium can be a single particle or few level quantum system. The study of QHE has shown remarkable similarity with standard thermodynamical models, thus raising issue what in thermodynamics. Our main result equivalence all engine type regime small action. They have same power, heat, efficiency, and they even relaxation rates modes. Furthermore, it that quantum-thermodynamic signature, i.e...

A new approach for viscoacoustic wave propagation is developed. The Boltzmann's superposition principle based on the general standard linear solid rheology implemented in equation of motion by introduction memory variables. This replaces conventional convolutional rheological relation, and thus complete time history material no longer required, equations become a coupled first-order system time. done direct expansion evolution operator Chebycheff polynomial series. resulting method highly...

The quantum Otto cycle serves as a bridge between the macroscopic world of heat engines and regime thermal devices composed from single element. We compile recent studies with harmonic oscillator working medium. This model has advantage that it is analytically trackable. In addition, an experimental realization been achieved employing ion in trap. review embedded field thermodynamics open systems. basic principles theory are explained by specific example illuminating definitions work heat....

Abstract Quantum optimal control, a toolbox for devising and implementing the shapes of external fields that accomplish given tasks in operation quantum device best way possible, has evolved into one cornerstones enabling technologies. The last few years have seen rapid evolution expansion field. We review here recent progress our understanding controllability open systems development application control techniques to also address key challenges sketch roadmap future developments.

Clausius' statement of the second law thermodynamics reads: Heat will flow spontaneously from a hot to cold reservoir. This should hold for transport energy through quantum network composed small subsystems each coupled heat When coupling between nodes is small, it seems reasonable construct local master equation node in contact with The evaluated by calculating flux after individual are coupled. We show analysing most simple two and reservoir, that description can result flowing reservoirs,...

A quantum absorption refrigerator driven by noise is studied with the purpose of determining limitations cooling to absolute zero. The model consists a working medium coupled simultaneously hot, cold and baths. Explicit expressions for power are obtained Gaussian Poisson white noise. consistent first second laws thermodynamics. third law quantified, J_c vanishes as proportional T_c^{alpha}, when T_c approach 0, where alpha =d+1 dissipation emission quanta described linear coupling thermal...

Quantum computation is based on implementing selected unitary transformations representing algorithms. A generalized optimal control theory used to find the driving field that generates a prespecified transformation. The approach independent of physical implementation quantum computer and it illustrated for one two qubit gates in model molecular systems, where only part Hilbert space computation.

The finite-time operation of a quantum-mechanical heat engine with working fluid consisting many noninteracting spin-1/2 systems is considered. driven by an external, time-dependent and nonrotating magnetic field. cycle consists two adiabats isotherms. analysis based on the time derivatives first second laws thermodynamics. Explicit relations linking quantum observables to thermodynamic quantities are developed. irreversible this studied in three cases: (1) sudden limit, where performance...

A new formulation for wave propagation in an anelastic medium is developed. The phenomenological theory of linear viscoelasticity provides the basis describing attenuation and dispersion seismic waves. concept a spectrum relaxation mechanisms represents convenient description constitutive relation viscoelastic solids; however, Boltzmann's superposition principle does not have straightforward implementation time-domain methods. This problem avoided by introduction memory variables which...

A new quantum mechanical time dependent integrator was used in the study of wave packet dynamics on potentials which include a deep well. The purpose to find conditions, if any, for complex formation. integrator, is stable, conserves energy and norm H++H2 system whose classical trajectory had been previously worked out. Almost no formation found its isotopic analogs. For high translational energies there good correspondence with results, while low where trajectories become complex,...

The dynamics of a quantum system driven by an external field is well described unitary transformation generated time-dependent Hamiltonian. inverse problem finding the that generates specific subject study. which can represent algorithm in computation imposed on subset states embedded larger Hilbert space. Optimal control theory used to solve inversion irrespective initial input state. A unified formalism based Krotov method developed leading different scheme. schemes are compared for...

Both X-ray crystallography and electronic structure calculations using the cc-pVDZ basis set at DFT B3LYP level were employed to study explosive properties of triacetone triperoxide (TATP) diacetone diperoxide (DADP). The thermal decomposition pathway TATP was investigated by a series that identified transition states, intermediates, final products. Counterintuitively, these predict explosion is not thermochemically highly favored event. It rather involves entropy burst, which result...