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An approach is developed for constructing simple analytical formulae accurately approximating solutions to eigenvalue problems of quantum mechanics. This approach is based on self-similar approximation theory. In order to derive…

Condensed Matter · Physics 2009-10-31 V. I. Yukalov , E. P. Yukalova , S. Gluzman

We propose a universal analytical method to study the dynamics of a multi-anticrossing system subject to driving by one single large-amplitude triangle pulse, within its time scales smaller than the dephasing time. Our approach can explain…

Quantum Physics · Physics 2015-05-27 Jindan Chen , Xueda Wen , Guozhu Sun , Yang Yu

A matrix inverse free method to solve time-dependent Schrodinger equation is presented. The method is not subject to form of Hamiltonian and adopting real space grid system such as structured and unstructured grid, and achieves the order N…

Computational Physics · Physics 2007-05-23 Katsuhiro Watanabe , Akihito Kikuchi

We construct a novel class of exact solutions to the Boltzmann equation, in both its classical and quantum formulation, for arbitrary collision laws. When the system is subjected to a specific external forcing, the precise form of which is…

Statistical Mechanics · Physics 2015-06-19 D. Guéry-Odelin , J. G. Muga , M. J. Ruiz-Montero , E. Trizac

Quantum metrology leverages quantum resources such as entanglement and squeezing to enhance parameter estimation precision beyond classical limits. While optimal quantum control strategies can assist to reach or even surpass the Heisenberg…

Quantum Physics · Physics 2025-10-17 Qifei Wei , Shengshi Pang

In this paper, we propose two time-splitting finite element methods to solve the semiclassical nonlinear Schr\"odinger equation (NLSE) with random potentials. We then introduce the multiscale finite element method (MsFEM) to reduce the…

Numerical Analysis · Mathematics 2025-02-12 Panchi Li , Zhiwen Zhang

Quantum ensemble systems arise in a variety of applications, including NMR spectroscopy and robust quantum control. While their theoretical properties have been extensively studied, relatively little attention has been given to the explicit…

Optimization and Control · Mathematics 2025-06-25 Ruikang Liang , Gong Cheng

Starting from our idea of combining the Feynman path integral spirit and the Dyson series kernel, we find an explicit and general form of time evolution operator that is a $c$-number function and a power series of perturbation including all…

Quantum Physics · Physics 2007-05-23 An Min Wang

This paper presents a quantum algorithm for solving the fractional Poisson equation \((-\Delta)^s u = f\) with \(s \in (0,1)\) on bounded domains. The proposed approach combines rational approximation techniques with quantum linear system…

Quantum Physics · Physics 2026-04-02 Yin Yang , Yue Yu , Long Zhang , Ming Zhou

We present experimental results on the preparation of a desired quantum state in a two-level system with the maximum possible fidelity using driving protocols ranging from generalizations of the linear Landau-Zener protocol to…

Quantum Physics · Physics 2012-11-08 N. Malossi , M. G. Bason , M. Viteau , E. Arimondo , R. Mannella , O. Morsch , D. Ciampini

We show that for a particular model, the quantum mechanical bootstrap is capable of finding exact results. We consider a solvable system with Hamiltonian $H=SZ(1-Z)S$, where $Z$ and $S$ satisfy canonical commutation relations. While this…

High Energy Physics - Theory · Physics 2024-02-07 Lewis Sword , David Vegh

This paper proposes a numerical method for solving time-dependent Schrodinger equations with finite spectral bandwidth, which applies to both periodic and non-periodic cases. We introduce the concept of Pulse Width Modulation (PWM), which…

Quantum Physics · Physics 2022-09-23 Qi-Ming Chen , Re-Bing Wu

We consider a system described by a controlled bilinear Schr{\"o}dinger equation with three external inputs. We provide a constructive method to approximately steer the system from a given energy level to a superposition of energy levels…

Optimization and Control · Mathematics 2015-02-25 Paolo Mason , Francesca Chittaro

We explore the recently discovered solution of the driven Tavis-Cummings model (DTCM). It describes interaction of arbitrary number of two-level systems with a bosonic mode that has linearly time-dependent frequency. We derive compact and…

Quantum Physics · Physics 2017-06-08 Chen Sun , Nikolai A. Sinitsyn

Computing many eigenpairs of the Schr{\"o}dinger operator presents a computational bottleneck in large-scale quantum simulations due to the global communication overhead of explicit orthogonalization. To address this issue, we propose a…

Numerical Analysis · Mathematics 2026-05-26 Shengyue Wang , Aihui Zhou

We consider the bilinear Schroedinger equation on a bounded one-dimensional domain and we provide explicit times such that the global exact controllability is verified. In addition, we show how to construct controls for the global…

Mathematical Physics · Physics 2019-05-03 Alessandro Duca

We propose a procedure to obtain exact analytical solutions to the time-dependent Schr\"{o}dinger equations involving explicit time-dependent Hermitian Hamitonians from solutions to time-independent non-Hermitian Hamiltonian systems and the…

Quantum Physics · Physics 2017-01-25 Andreas Fring , Thomas Frith

We calculate the propagator and the transition probabilities for a coherently driven three-state quantum system. The energies of the three states change linearly in time, whereas the interactions between them are pulse-shaped. We derive a…

Quantum Physics · Physics 2009-11-13 S. S. Ivanov , N. V. Vitanov

We present a refinement of the Spectral Method by incorporating an optimization method into it and generalize it to two space dimensions. We then apply this Refined Spectral Method as an extremely accurate technique for finding the bound…

Mathematical Physics · Physics 2007-05-23 P. Pedram , M. Mirzaei , S. S. Gousheh

This paper aims at obtaining, by means of integral transforms, analytical approximations in short times of solutions to boundary value problems for the one-dimensional reaction-diffusion equation with constant coefficients. The general form…

Analysis of PDEs · Mathematics 2023-05-23 Anani Kwassi