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We utilize genetic algorithms to find optimal dynamical decoupling (DD) sequences for a single-qubit system subjected to a general decoherence model under a variety of control pulse conditions. We focus on the case of sequences with equal…

Quantum Physics · Physics 2013-11-13 Gregory Quiroz , Daniel A. Lidar

We present a number of new physical systems that may be addressed using methods of time dependent transformation. A recap of results available for two-state systems is given, with particular emphasis on the AC stark effect. We give some…

Quantum Physics · Physics 2023-06-05 Peter Morrison

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

From celestial mechanics to quantum theory of atoms and molecules, perturbation theory has played a central role in natural sciences. Particularly in quantum mechanics, the amount of information needed for specifying the state of a…

Quantum Physics · Physics 2016-07-06 Yudong Cao , Sabre Kais

In many physical problems it is not possible to find an exact solution. However, when some parameter in the problem is small, one can obtain an approximate solution by expanding in this parameter. This is the basis of perturbative methods,…

Mathematical Physics · Physics 2007-05-23 Paolo Amore

We use a perturbative approach to evaluate transition amplitudes corresponding to quantum friction, for a scalar model describing an atom which moves at a constant velocity, close to a material plane. In particular, we present results on…

High Energy Physics - Theory · Physics 2023-08-29 Aitor Fernández , C. D. Fosco

In this study, we address the challenge of controlling quantum systems under environmental influences using the theory of dynamical invariants. We employ a reverse engineering approach to develop control protocols designed to be robust…

Quantum Physics · Physics 2024-08-20 Loris Maria Cangemi , Hilario Espinós , Ricardo Puebla , Erik Torrontegui , Amikam Levy

It is known that the same physical system can be described by different effective theories depending on the scale at which it is observed. In this work, we formulate a prescription for finding the unitary that best approximates the large…

Quantum Physics · Physics 2026-02-17 Antonio F. Rotundo , Paolo Perinotti , Alessandro Bisio

Many recent advancements in quantum computing leverage strong drives on nonlinear systems for state preparation, signal amplification, or gate operation. However, the interplay within such strongly driven system introduces multi-scale…

Quantum Physics · Physics 2024-08-02 Leon Bello , Wentao Fan , Aditya Gandotra , Hakan E. Türeci

A general method is discussed to obtain Markovian master equations which describe the interaction with the environment in a microscopic and non-perturbative fashion. It is based on combining time-dependent scattering theory with the concept…

Quantum Physics · Physics 2009-11-13 Klaus Hornberger

Accurate time-delay measurement is at the core of many modern technologies. Here, we present a temporal-mode demultiplexing scheme that achieves the ultimate quantum precision for the simultaneous estimation of the temporal centroid, the…

The optimal control of two-level systems by time-dependent laser fields is studied using a variational theory. We obtain, for the first time, general analytical expressions for the optimal pulse shapes leading to global maximization or…

Quantum Physics · Physics 2009-11-10 Martin E. Garcia , Ilia Grigorenko

The coherence times achieved with continuous dynamical decoupling techniques are often limited by fluctuations in the driving amplitude. In this work, we use time-dependent phase-modulated continuous driving to increase the robustness…

Quantum Physics · Physics 2017-08-22 D. Farfurnik , N. Aharon , I. Cohen , Y. Hovav , A. Retzker , N. Bar-Gill

We develop a Magnus formalism for periodically driven systems which provides an expansion both in the driving term and the inverse driving frequency, applicable to isolated and dissipative systems. We derive explicit formulas for a driving…

Superconductivity · Physics 2016-10-14 B. Zhu , T. Rexin , L. Mathey

A reliable and efficient computation of the entire single-particle spectrum of correlated molecules is an outstanding challenge in the field of quantum chemistry, with standard density functional theory approaches often giving an inadequate…

Chemical Physics · Physics 2021-10-08 Oliver J. Backhouse , Alejandro Santana-Bonilla , George H. Booth

In this article, we formulate the study of the unitary time evolution of systems consisting of an infinite number of uncoupled time-dependent harmonic oscillators in mathematically rigorous terms. We base this analysis on the theory of a…

Mathematical Physics · Physics 2009-10-06 Daniel Gómez Vergel , Eduardo J. S. Villaseñor

The dynamics of strongly interacting trapped dilute Fermi gases (dilute in the sense that the range of interatomic potential is small compared with inter-particle spacing) is investigated in a single-equation approach to the time-dependent…

Soft Condensed Matter · Physics 2009-02-05 Yeong E. Kim , Alexander L. Zubarev

We present a time-parallelization method that enables to accelerate the computation of quantum optimal control algorithms. We show that this approach is approximately fully efficient when based on a gradient method as optimization solver:…

Optimization and Control · Mathematics 2016-05-04 Mohamed-Kamel Riahi , Julien Salomon , S. J. Glaser , D Sugny

By using stochastic ensembles of walkers in physical and in one-body Hilbert spaces the recently proposed time-dependent quantum Monte Carlo (TDQMC) method offers the unique capability to calculate one-body density matrices at fully…

Quantum Physics · Physics 2025-02-07 Ivan P. Christov

We study classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a probability distribution to the physical time, which is assumed to be discrete. - This is motivated by the ``timeless''…

General Relativity and Quantum Cosmology · Physics 2015-06-25 H. -T. Elze