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Hamiltonian simulation becomes more challenging as the underlying unitary becomes more oscillatory. In such cases, an algorithm with commutator scaling and a weak dependence, such as logarithmic, on the derivatives of the Hamiltonian is…

Quantum Physics · Physics 2025-05-08 Di Fang , Diyi Liu , Rahul Sarkar

We propose an algorithm for simulating the dynamics of a geometrically local Hamiltonian $A$ under a small geometrically local perturbation $\alpha B$. In certain regimes, the algorithm achieves the optimal scaling and outperforms the…

Quantum Physics · Physics 2024-04-05 Kunal Sharma , Minh C. Tran

We investigate the Magnus expansion for a generic time-dependent two-level system under single-axis driving.By virtue of the su(2) Lie algebra, the expansion is decomposed into a commutator-free form. To illustrate the usefulness of the…

Quantum Physics · Physics 2026-05-14 Chen Wei , Frank Großmann

The Floquet-Magnus expansion is a useful tool to calculate an effective Hamiltonian for periodically driven systems. In this study, we investigate the convergence of the expansion for a one-body nonlinear system in a continuous space, a…

Quantum Physics · Physics 2020-01-01 Taiki Haga

We show that Liouville-von Neumann approach to quantum mechanical systems, which demands the existence of invariant operators, reproduces the time-dependent variational Gaussian approximation. We find the effective action of the…

High Energy Physics - Theory · Physics 2018-02-14 Hyeong-Chan Kim , Jae Hyung Yee

We describe a numerical method which allows us to go beyond the classical approximation for the real-time dynamics of many-body systems by approximating the many-body Wigner function by the most general Gaussian function with time-dependent…

High Energy Physics - Theory · Physics 2018-03-29 Pavel Buividovich , Masanori Hanada , Andreas Schäfer

The computation of the Schr\"odinger equation featuring time-dependent potentials is of great importance in quantum control of atomic and molecular processes. These applications often involve highly oscillatory potentials and require…

Numerical Analysis · Mathematics 2018-01-23 Arieh Iserles , Karolina Kropielnicka , Pranav Singh

In this work, we have applied the integrals of motion method in a nonunitary approach and so obtained the time-dependent displacement and squeezed parameters of the coherent squeezed states (CSS). On its turn, CSS for one-dimensional…

Quantum Physics · Physics 2021-05-21 A. S. Pereira , A. S. Lemos

In a classical scattering problem, the classical eikonal is defined as the generator of the canonical transformation that maps in-states to out-states. It can be regarded as the classical limit of the log of the quantum S-matrix. In a…

High Energy Physics - Theory · Physics 2025-01-28 Joon-Hwi Kim , Jung-Wook Kim , Sungsoo Kim , Sangmin Lee

We propose a computationally efficient and systematically convergent approach for elastodynamics simulations. We recast the second-order dynamical equation of elastodynamics into an equivalent first-order system of coupled equations, so as…

Numerical Analysis · Mathematics 2024-05-09 Paavai Pari , Bikash Kanungo , Vikram Gavini

In the context of time-subordinated Brownian motion models, Fourier theory and methodology are proposed to modelling the stochastic distribution of time increments. Gaussian Variance-Mean mixtures and time-subordinated models are reviewed…

Mathematical Finance · Quantitative Finance 2025-10-21 Rohan Shenoy , Peter Kempthorne

The ubiquitous effects of the environment on quantum-mechanical systems generally cause temporally correlated fluctuations. This particularly holds for systems of interest for quantum computation where such effects lead to correlated…

Quantum Physics · Physics 2025-04-23 Balázs Gulácsi , Guido Burkard

Cooling methods and particle slowers as well as accelerators are basic tools for fundamental research and applications in different fields and systems. We put forward a generic mechanism to scale the momentum of a particle, regardless of…

Quantum Physics · Physics 2020-11-04 J. G. Muga , S. Martínez-Garaot , M. Pons , M. Palmero , A. Tobalina

This paper summarises a numerical investigation of phase mixing in time-independent Hamiltonian systems that admit a coexistence of regular and chaotic phase space regions, allowing also for low amplitude perturbations idealised as periodic…

Astrophysics · Physics 2007-05-23 Henry E. Kandrup , Steven J. Novotny

This work explores the behaviour of a noncommutative harmonic oscillator in a time-dependent background, as previously investigated in [1]. Specifically, we examine the system when expressed in terms of commutative variables, utilizing a…

Quantum Physics · Physics 2024-07-10 Manjari Dutta , Shreemoyee Ganguly , Sunandan Gangopadhyay

We investigate time-adaptive Magnus-type integrators for the numerical approximation of a Mott transistor. The rapidly attenuating electromagnetic field calls for adaptive choice of the time steps. As a basis for step selection,…

We study the non-Markovian decoherence and disentanglement dynamics of dissipative quantum systems with special emphasis on non-Gaussian continuous variable systems. The dynamics are described by the Hu-Paz-Zhang master equation of quantum…

Quantum Physics · Physics 2007-11-21 C. Hoerhammer , H. Buettner

Many real time-series exhibit behavior adequate to long range dependent data. Additionally very often these time-series have constant time periods and also have characteristics similar to Gaussian processes although they are not Gaussian.…

Data Analysis, Statistics and Probability · Physics 2017-01-04 A. Kumar , A. Wyłomańska , R. Połoczański , S. Sundar

We apply boson expansion methods to an extended Lipkin-Meshkov-Glick model including anharmonicities in analogy with previous microscopic calculations. We study the effects of different approximations present in these calculations, among…

Nuclear Theory · Physics 2009-10-31 C. Volpe , Ph. Chomaz , M. V. Andres , F. Catara , E. G. Lanza

This article introduces a novel construction of the two-dimensional fractional Brownian motion (2D fBm) with dependent components. Unlike similar models discussed in the literature, our approach uniquely accommodates the full range of model…