Toward scalable information processing with ultracold polar molecules in an electric field: a numerical investigation

We numerically investigate the possibilities of driving quantum algorithms with laser pulses in a register of ultracold NaCs polar molecules in a static electric field. We focuse on the possibilities of performing scalable logical operations by considering circuits that involve intermolecular gates (implemented on adjacent interacting molecules) to enable the transfer of information from one molecule to another during conditional laser-driven population inversions. We study the implementation of an arithmetic operation (the addition of 0 or 1 on a binary digit and a carry in) which requires population inversions only and the Deutsch-Josza algorithm which requires a control of the phases. Under typical experimental conditions, our simulations show that high fidelity logical operations involving several qubits can be performed in a time scale of a few hundred of microseconds, opening promising perspectives for the manipulation of a large number of qubits in these systems

Re-exploring Control Strategies in a Non-Markovian Open Quantum System by Reinforcement Learning

In this study, we reexamine a recent optimal control simulation targeting the preparation of a superposition of two excited electronic states in the UV range in a complex molecular system. We revisit this control from the perspective of reinforcement learning, offering an efficient alternative to conventional quantum control methods. The two excited states are addressable by orthogonal polarizations and their superposition corresponds to a right or left localization of the electronic density. The pulse duration spans tens of femtoseconds to prevent excitation of higher excited bright states what leads to a strong perturbation by the nuclear motions. We modify an open source software by L. Giannelli et al., Phys. Lett. A, 434, 128054 (2022) that implements reinforcement learning with Lindblad dynamics, to introduce non-Markovianity of the surrounding either by timedependent rates or more exactly by using the hierarchical equations of motion with the QuTiP-BoFiN package. This extension opens the way to wider applications for non-Markovian environments, in particular when the active system interacts with a highly structured noise.Comment: 18 pages, 11 figure

Analysis of the non-Markovianity for electron transfer reactions in an oligothiophene-fullerene heterojunction

The non-Markovianity of the electron transfer in an oligothiophene-fullerene heterojunction described by a spin-boson model is analyzed using the time dependent decoherence canonical rates and the volume of accessible states in the Bloch sphere. The dynamical map of the reduced electronic system is computed by the hierarchical equations of motion methodology (HEOM) providing an exact dynamics. Transitory witness of non-Markovianity is linked to the bath dynamics analyzed from the HEOM auxiliary matrices. The signature of the collective bath mode detected from HEOM in each electronic state is compared with predictions of the effective mode extracted from the spectral density. We show that including this main reaction coordinate in a one-dimensional vibronic system coupled to a residual bath satisfactorily describes the electron transfer by a simple Markovian Redfield equation. Non-Markovianity is computed for three inter fragment distances and compared with a priori criterion based on the system and bath characteristic timescales

Survey of the Hierarchical Equations of Motion in Tensor-Train format for non-Markovian quantum dynamics

This work is a pedagogical survey about the hierarchical equations of motion and their implementation with the tensor-train format. These equations are a great standard in non-perturbative non-Markovian open quantum systems. They are exact for harmonic baths in the limit of relevant truncation of the hierarchy. We recall the link with the perturbative second order time convolution equations also known as the Bloch-Redfield equations. Some theoretical tools characterizing non-Markovian dynamics such as the non- Markovianity measures or the dynamical map are also briefly discussed in the context of HEOM simulations. The main points of the tensor-train expansion are illustrated in an example with a qubit interacting with a bath described by a Lorentzian spectral density. Finally, we give three illustrative applications in which the system-bath coupling operator is similar to that of the analytical treatment. The first example revisits a model in which population-to-coherence transfer via the bath creates a long-lasting coherence between two states. The second one is devoted to the computation of stationary absorption and emission spectra. We illustrate the link between the spectral density and the Stokes shift in situations with and without nonadiabatic interaction. Finally, we simulate an excitation transfer when the spectral density is discretized by undamped modes to illustrate a situation in which the TT formulation is more efficient than the standard one.Comment: 33 pages, 16 figure

Control of molecular dynamics with zero-area fields: Application to molecular orientation and photofragmentation

The constraint of time-integrated zero-area on the laser field is a fundamental, both theoretical and experimental requirement in the control of molecular dynamics. By using techniques of local and optimal control theory, we show how to enforce this constraint on two benchmark control problems, namely molecular orientation and photofragmentation. The origin and the physical implications on the dynamics of this zero-area control field are discussed.Comment: 19 pages, 7 figure

Laser control of ultracold molecule formation: The case of RbSr

We have studied the formation of ultracold RbSr molecules with laser pulses. After discussing the advantages of the Mott insulator phase for the control with pulses, we present two classes of strategies. The first class involves two electronic states. Two extensions of stimulated Raman adiabatic passage (STIRAP) for multi-level transitions are used : alternating STIRAP (A-STIRAP) and straddle STIRAP (S-STIRAP). Both transfer dynamics are modeled and compared. The second class of strategies involves only the electronic ground state and uses infrared (IR)/TeraHertz (THz) pulses. The chemical bond is first created by the application of a THz chirped pulse or $\pi$-pulse. Subsequently, the molecules are transferred to their ro-vibrational ground state using IR pulses. For this last step, different optimized pulse sequences through optimal control techniques, have been studied. The relative merits of these strategies in terms of efficiency and robustness are discussed within the experimental feasibility criteria of present laser technology

Knowledge management in construction

Na upravljanje z znanjem lahko gledamo kot na jasen in sistematičen način zajetja informacij in znanja nekega podjetja, njegovega razvoja, izdelkov, dela, trgovanja, strank in konkurence združenega na enem mestu, do katerega lahko dostopa ustrezno osebje, razpolaga z njim in ga koristno unovči. Gre za obširen in za vsako podjetje unikaten proces, ki predstavlja upravljanje z razumskimi sposobnostmi, zmožnostmi in spretnostmi zaposlenih v podjetju z namenom, da bi izboljšali učinkovitost podjetja in lažje obvladovali spremembe. Gradbeništvo je izredno razvejana in raznolika industrijska panoga, ki jo spremljajo številne spremembe in inovacije. Uporabljeni materiali, pogoji okolja, način gradnje, predvsem pa partnerji in izdelki se spreminjajo od projekta do projekta, po drugi strani pa lahko opazimo, da imajo gradbeni projekti tudi veliko skupnih značilnosti. Učinkovito upravljanje z znanjem v gradbenih podjetjih mora te posebnosti zaobjeti. V svetu so v zadnjih letih nastali številni modeli za upravljanje z znanjem. Z implementacijo različnih modelov si gradbeno podjetje lahko ustvari svoj sistem za zajemanje tako tihega kot eksplicitnega znanja in tako pripomore k večjemu poslovnemu uspehu ter prednosti pred konkurenco. Diplomsko delo predstavlja pomen in glavne značilnosti upravljanja z znanjem v gradbeništvu. Nadalje delo povzema nekatere izbrane modele za upravljanje z znanjem v gradbeni industriji, ki so opisani v literaturi. Analizirali smo tudi dve uspešni slovenski podjetji, pri katerih smo skušali s pomočjo izdelanega vprašalnika ter dobljenih odgovorov ugotoviti, v kolikšni meri je prisotno zavedanje pomembnosti upravljanja z znanjem in kako lahko s pomočjo le-tega njihovo poslovanje še izboljšajo. V obeh primerih se je izkazalo, da gre za sodobni podjetji, ki sledita svetovnim trendom in sta pripravljeni na tem področju graditi še naprej. Izdelek zaključujemo s predlogom obrazca o zajemu informacij iz izvedenega projekta, ki bi gradbenim podjetjem pomagal pri vgrajevanju povratnih informacij v naslednji projekt.Knowledge management could be viewed as an explicit and systematic approach to capturing information and knowledge about a company, its processes, products, services, markets, customers and competitors and then storing this in a place where relevant personnel can access, distribute it and make use of it. It is an ongoing and unique processit is management of intellectual capabilities, potentials and skills of people with the aim of improving performance and coping with change. Construction industry is an extremely complex sector accompanied by numerous changes and innovation. Materials, technologies, environmental conditions but most of all co-workers and finished products change from one project to anotheron the other hand, however, several common features can be observed in various construction projects. This has to be taken into account, if an efficient knowledge management in a construction company wants to be achieved. Several knowledge management models have been developed over the past years. A construction company needs to get acquainted with the different models in order to create its own system for acquiring both tacit and explicit knowledge, which contributes to improved business success and the company\u27s competitive edge. The thesis discusses the importance and main characteristics of knowledge management in construction. Selected knowledge management models applied to construction from the available literature are described. The analysis of two Slovenian construction companies is carried out by using a questionnaire. The obtained answers show that both companies are aware of the importance of knowledge management, and that they are willing to further develop this area. In the last part of the thesis, a draft form for data extraction is proposed that would enable the transfer of knowledge and experience from a completed project into a new one

Contrôle de la dynamique de systèmes complexes (Application à l'information quantique et classique)

ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Dynamique quantique autour de régions clef dans les paysages énergétiques

La dynamique quantique appliquée à l'étude théorique de la réactivité chimique d'un système moléculaire isolé nécessite, au-delà d'une certaine taille, de recourir à des approximations. La méthode des hamiltoniens contraints a été utilisée ici afin de ne traiter explicitement qu'un nombre limité de degrés de liberté par des techniques de paquets d'ondes. Les trois thèmes abordés concernent des processus élémentaires conditionnés par des régions clef dans les paysages énergétiques et donnant lieu à des effets relevant d'un traitement quantique. (i) L'étude de la photodissociation compétitive du chlorure de bromoacétyle a été réalisée à l'aide d'un modèle non adiabatique à deux états électroniques et deux modes de déformation pour confirmer l'hypothèse d'un mécanisme de piège diabatique et expliquer l'inversion du rapport de branchement mesuré expérimentalement. (ii) La problématique de la bifurcation d'un chemin de réaction a été illustrée par l'étude de l'isomérisation du radical méthoxy et de la cycloaddition du cyclopentadiène et de deux de ses dérivés substitués. Nous avons relié l'état initial de préparation du paquet d'ondes au caractère plus ou moins séquentiel ou concerté du mécanisme effectivement suivi. (iii) La probabilité cumulative de réaction est l'ingrédient fondamental du calcul de constantes de vitesse par des méthodes quantiques. Nous avons effectué un calcul MCTDH de cette quantité dans le cas de l'isomérisation du cyanure d'hydrogène caractérisée par un effet tunnel marqué. Les résultats ont été comparés à ceux obtenus via des méthodes standard de propagation et d'application directe du projecteur microcanonique.Quantum dynamics applied to the theoretical study of chemical reactivity requires, beyond a certain size, to resort to some approximations. The constrained Hamiltonian method has been used in order to treat explicitly only a limited number of degrees of freedom by wave packet techniques. The three broached topics concern elementary processes conditioned by key regions in energy landscapes. They give rise to effects that need a quantum treatment. (i) The study of the competitive photodissociation of bromoacetyle chloride has been done with a two state and two shape mode nonadiabatic model in order to confirm the hypothesis of a diabatic trapping and explain the inverted branching ratio experimentally measured. (ii) The problematic of a bifurcating reaction path has been illustrated by the studies of the methoxy radical isomerization and of the cyclopentadiene cycloaddition as well as the cycloaddition of two of its substituted derivatives. We have linked the initial prepared state of the wave packet to the more or less stepwise or concerted character of the mechanism effectively followed. (iii) The cumulative reaction probability is the fundamental ingredient of the computation of rate constants by quantum methods. We have done a MCTDH calculation of this quantity in the case of the isomerization of hydrogen cyanide characterized by strong tunneling. These results have been compared to those obtained by standard propagation methods and direct application of the microcanonical projector.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF