arXiv subjects

Duje Bonacci

Publications and source records attributed to Duje Bonacci.

5 recordsLinked to original sources

arXiv2025

Variational Resolution of the Abraham-Lorentz-Dirac Equation Pathologies

We propose a structural variational resolution of the Abraham-Lorentz-Dirac (ALD) pathologies. By deriving the Variational Kinematic Constraint (VKC) and the Variational Dynamics Constraint (VDC) from the particle's proper-time perspective, we show that self-induced variations are forbidden and dynamics arise solely from first-order proper-time variations of external fields. Consequently, self-force terms are excluded at the variational level, eliminating runaway solutions and non-causal behavior without regularization. Our framework further provides a first-principles derivation of minimal coupling and reveals gauge invariance as a necessary consequence of proper-time-based variational structure.

physics.class-ph↗

arXiv2005

Analytic pulse design for selective population transfer in many-level quantum systems: optimizing the pulse duration

In the previous paper on this topic it was shown how, for a pulse of arbitrary shape and duration, the drive frequency can be analytically optimized to maximize the amplitude of the population oscillations between the selected two levels in a general many level quantum system. It was shown how the standard Rabi theory can be extended beyond the simple two-level systems. Now, in order to achieve the quickest and as complete as possible population transfer between two pre-selected levels, driving pulse should be tailored so that it produces only a single half-oscillation of the population. In this paper, this second (and final) step towards the controlled population transfer using modified (i.e. many level system) Rabi oscillations is discussed. The results presented herein can be regarded as an extension of the standard $π$-pulse theory - also strictly valid only in the two level systems - to the coherently driven population oscillations in general many level systems.

quant-ph↗

arXiv2004

Analytic pulse design for selective population transfer in many-level quantum systems: maximizing amplitude of population oscillations

State selective preparation and manipulation of discrete-level quantum systems such as atoms, molecules or quantum dots is a the ultimate tool for many diverse fields such as laser control of chemical reactions, atom optics, high-precision metrology and quantum computing. Rabi oscillations are one of the simplest, yet potentially quite useful mechanisms for achieving such manipulation. Rabi theory establishes that in the two-level systems resonant drive leads to the periodic and complete population oscillations between the two system levels. In this paper an analytic optimization algorithm for producing Rabi-like oscillations in the general discrete many-level quantum systems is presented.

quant-ph↗

arXiv2004

Inducing complete population oscillations in systems with externally induced dipole moments

A two level system is considered which has no static dipole moment, e.g. molecule $H_2$ in its ground electronic state. If strong enough external field is applied, it will dynamically distort such a system and supply it with time (and field) dependent dipole moment. Although it is impossible to do so in the undistorted system which has no coupling to the dipole component of the external field, having induced in it a dipole moment, the rotational and vibrational dynamics of such system can be manipulated using lasers. In this work, a system is considered in which the external perturbation dynamically induces the transition dipole moment between only two distinct levels. The aim of the work is to show how the driving pulse can be analytically designed, that will produce Rabi-like complete population oscillations between the two levels.

quant-ph↗

arXiv2003

Rabi Profile Framework: A Simple Analytical and Graphical Toolkit for Quantum Control

We introduce the \emph{Rabi profile}, the \emph{Rabi spectrum} and the \emph{Rabi leak} as triad of mathematically rigorous but conceptually transparent quantum-control tools that provide a framework for assessing the feasibility and selectivity of coherent state control in quantum systems with arbitrarily many levels, without recourse to numerical simulation. As the rigorous foundation for this framework, we present a self-contained discussion of the rotating-wave approximation (RWA) and its limits, suitable for use as classroom material. We illustrate its practical utility by application to design of superconducting transmon qubits. Because it reduces complex quantum control questions to elementary frequency-domain reasoning, the Rabi profile framework is intended to serve equally as a research diagnostic and as a pedagogical bridge between introductory quantum mechanics and contemporary quantum technologies.

quant-ph↗