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We discuss a simple scheme for preparing atoms and molecules in an arbitrary preselected coherent superposition of quantum states. The technique, which we call fractional stimulated Raman adiabatic passage ({\it f-STIRAP}), is based upon…

Quantum Physics · Physics 2007-05-23 N. V. Vitanov , K. -A. Suominen , B. W. Shore

We examine the adiabatic preparation of spatially-ordered Rydberg excitations of atoms in finite one-dimensional lattices by frequency-chirped laser pulses, as realized in a number of recent experiments simulating quantum Ising model. Our…

Quantum Physics · Physics 2022-12-13 A. F. Tzortzakakis , D. Petrosyan , M. Fleischhauer , K. Mølmer

In this paper we propose a novel decision making architecture for Robust Model Predictive Path Integral control (RMPPI) and investigate its performance guarantees and applicability to off-road navigation. Key building blocks of the proposed…

Systems and Control · Electrical Eng. & Systems 2021-02-19 Manan Gandhi , Bogdan Vlahov , Jason Gibson , Grady Williams , Evangelos A. Theodorou

Covariant density functional theory, in the framework of self-consistent Relativistic Mean Field (RMF) and Relativistic Random Phase approximation (RPA), is for the first time applied to axially deformed nuclei. The fully self-consistent…

Nuclear Theory · Physics 2009-09-15 D. Pena Arteaga , P. Ring

We study dynamics of a two-color photoassociation of atoms into diatomic molecules via nonlinear Stimulated Raman adiabatic passage (STIRAP) process. This system has a famous counterpart in (linear) quantum mechanics, and been discussed…

Other Condensed Matter · Physics 2007-12-13 A. P. Itin , S. Watanabe

This paper describes a method to do ab initio molecular dynamics in electronically excited systems within the random phase approximation (RPA). Using a dynamical variational treatment of the RPA frequency, which corresponds to the…

Condensed Matter · Physics 2009-10-31 Eric R. Bittner , D. S. Kosov

A method is implemented to perform "fast" adiabatic variation of the spin Hamiltonian by imposing the constant adiabaticity condition. The method is applied to improve the performance of singlet-state Nuclear Magnetic Resonance (NMR)…

Path Planning for stochastic hybrid systems presents a unique challenge of predicting distributions of future states subject to a state-dependent dynamics switching function. In this work, we propose a variant of Model Predictive Path…

We generate half-excited symmetric Dicke states of two and four ions. We use multi-level stimulated Raman adiabatic passage (STIRAP) whose intermediate states are phonon Fock states. This process corresponds to the spin squeezing operation…

Quantum Physics · Physics 2015-06-11 Atsushi Noguchi , Kenji Toyoda , Shinji Urabe

In this paper, a non-intrusive reduced-order model (ROM) for parametric reactor kinetics simulations is presented. Time-dependent ROMs are notoriously data intensive and difficult to implement when nonlinear multiphysics phenomena are…

Numerical Analysis · Mathematics 2023-03-17 Zachary K. Hardy , Jim. E. Morel

There has been a problem of gauge ambiguities with the Rabi Hamiltonian due to the fact that it can be derived from two formally different but physically equivalent fundamental Hamiltonians. This problem has recently been resolved for…

Quantum Physics · Physics 2023-06-22 Christopher J. Ryu , Dong-Yeop Na , Weng C. Chew

We propose a new quantum transition-state theory for calculating Fermi's golden-rule rates in complex multidimensional systems. This method is able to account for the nuclear quantum effects of delocalization, zero-point energy and…

Chemical Physics · Physics 2019-03-27 Manish J. Thapa , Wei Fang , Jeremy O. Richardson

Here, we report on the nonlinear ionization of argon atoms in the short wavelength regime using ultraintense x rays from the European XFEL. After sequential multiphoton ionization, high charge states are obtained. For photon energies that…

Fermi's golden rule describes the leading-order behaviour of the reaction rate as a function of the diabatic coupling. Its asymptotic $(\hbar \rightarrow 0)$ limit is the semiclassical golden-rule instanton rate theory, which rigorously…

Chemical Physics · Physics 2022-05-18 George Trenins , Jeremy O. Richardson

The implementation of static artificial magnetic fields in ultracold atomic systems has become a powerful tool, e.g. for simulating quantum-Hall physics with charge-neutral atoms. Taking an interacting bosonic flux ladder as a minimal…

Quantum Gases · Physics 2021-07-07 Botao Wang , Xiao-Yu Dong , F. Nur Ünal , André Eckardt

Coherent manipulation of quantum states is of crucial importance in accurate control of a quantum system. A fundamental goal is coherently transferring the population of a desired state with near-unit fidelity. For this propose, we…

Atomic Physics · Physics 2018-12-05 Luyao Yan , Dandan Ma , Dongmin Yu , Jing Qian

The mapping approach addresses the mismatch between the continuous nuclear phase space and discrete electronic states by creating an extended, fully continuous phase space using a set of harmonic oscillators to encode the populations and…

Chemical Physics · Physics 2019-09-30 Maximilian A. C. Saller , Aaron Kelly , Jeremy O. Richardson

Path Integral Molecular Dynamics (PIMD) is a well established simulation technique to compute exact equilibrium properties for a quantum system using classical trajectories in an extended phase space. Standard PIMD simulations are…

Chemical Physics · Physics 2024-11-20 Britta A. Johnson , Siyu Bu , Christopher J. Mundy , Nandini Ananth

The ring-polymer instanton approach is applied to compute the ground-state tunnelling splitting of four isotopomers of the formic acid dimer using the accurate PES of Qu and Bowman [Phys. Chem. Chem. Phys., 2016, 18, 24835]. As well as…

Chemical Physics · Physics 2017-08-23 Jeremy O. Richardson

An exact approach to compute physical properties for general multi-electronic-state (MES) systems in thermal equilibrium is presented. The approach is extended from our recent progress on path integral molecular dynamics (PIMD) [J. Chem.…

Chemical Physics · Physics 2017-11-22 Xinzijian Liu , Jian Liu