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We consider a basic model of the lossless interaction between a moving two-level atom and a standing-wave single-mode laser field. Classical treatment of the translational atomic motion provides the semiclassical Hamilton-Schrodinger…

Atomic Physics · Physics 2012-05-29 S. V. Prants

We report on collective non-linear dynamics in an optical lattice formed inside a high finesse ring cavity in a so far unexplored regime, where the light shift per photon times the number of trapped atoms exceeds the cavity resonance…

Quantum Physics · Physics 2009-11-10 B. Nagorny , Th. Elsaesser , A. Hemmerich

There have been considerable research efforts devoted to quantum simulations of Fermi-Hubbard model with ultracold atoms loaded in optical lattices. In such experiments, the antiferromagnetically ordered quantum state has been achieved at…

Quantum Gases · Physics 2021-04-21 Jue Nan , Jian Lin , Yuchen Luo , Bo Zhao , Xiaopeng Li

We present a semiclassical quantization condition, i.e., quantum-classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller's trace formula to a…

Chemical Physics · Physics 2015-10-21 Mikiya Fujii , Koichi Yamashita

We derive equations for the strongly coupled system of light and dense atomic ensembles. The formalism includes an arbitrary internal level structure for the atoms and is not restricted to weak excitation of atoms by light. In the low light…

Atomic Physics · Physics 2016-06-07 Mark D. Lee , Stewart D. Jenkins , Janne Ruostekoski

We experimentally investigate a scheme for studying lattice transport phenomena, based on the controlled momentum-space dynamics of ultracold atomic matter waves. In the effective tight-binding models that can be simulated, we demonstrate…

Quantum Gases · Physics 2016-07-12 Eric J. Meier , Fangzhao Alex An , Bryce Gadway

We present experimental evidence of the successful closed-loop optimization of the dynamics of cold atoms in an optical lattice. We optimize the loading of an ultracold atomic gas minimizing the excitations in an array of one-dimensional…

Quantum Physics · Physics 2014-01-08 S. Rosi , A. Bernard , N. Fabbri , L. Fallani , C. Fort , M. Inguscio , T. Calarco , S. Montangero

We consider the time dependent dynamics of an atom in a two-color pumped cavity, longitudinally through a side mirror and transversally via direct driving of the atomic dipole. The beating of the two driving frequencies leads to a time…

Quantum Physics · Physics 2015-09-30 T. Hinkel , H. Ritsch , C. Genes

A generalized formalism of the so-called non-adiabatic quantum molecular dynamics is presented, which applies for atomic many-body systems in external laser fields. The theory treats the nuclear dynamics and electronic transitions…

Atomic Physics · Physics 2007-05-23 Thomas Kunert , Ruediger Schmidt

We perform on-the-fly non-adiabatic molecular dynamics simulations using the symmetrical quasi-classical (SQC) approach with the recently suggested molecular Tully models: ethylene and fulvene. We attempt to provide benchmarks of the SQC…

Chemical Physics · Physics 2021-09-15 Braden M. Weight , Arkajit Mandal , Pengfei Huo

Nonadiabatic molecular dynamics simulations aim to describe the coupled electron-nuclear dynamics of molecules in excited electronic states. These simulations have been applied to understand a plethora of photochemical and photophysical…

This paper provides the first ab-initio on-the-fly example of using the Quasi-Diabatic (QD) scheme for non-adiabatic simulations with diabatic dynamics approaches. The QD scheme provides a seamless interface between diabatic quantum…

Computational Physics · Physics 2019-08-15 Wanghuai Zhou , Arkajit Mandal , Pengfei Huo

The theoretical investigation of non-adiabatic processes is hampered by the complexity of the coupled electron-nuclear dynamics beyond the Born-Oppenheimer approximation. Classically, the simulation of such reactions is limited by the…

Quantum Physics · Physics 2021-01-06 Pauline J. Ollitrault , Guglielmo Mazzola , Ivano Tavernelli

Quantum simulations of Fermi-Hubbard models have been attracting considerable efforts in the optical lattice research, with the ultracold anti-ferromagnetic atomic phase reached at half filling in recent years. An unresolved issue is to…

Quantum Gases · Physics 2019-12-11 Jian Lin , Jue Nan , Yuchen Luo , Xing-Can Yao , Xiaopeng Li

Nonadiabatic molecular dynamics occur in a wide range of chemical reactions and femtochemistry experiments involving electronically excited states. These dynamics are hard to treat numerically as the system's complexity increases and it is…

Chemical Physics · Physics 2021-07-28 Haifeng Lang , Oriol Vendrell , Philipp Hauke

We introduce a new picture of vacuum decay which, in contrast to existing semiclassical techniques, provides a real-time description and does not rely on classically-forbidden tunneling paths. Using lattice simulations, we observe vacuum…

High Energy Physics - Theory · Physics 2019-07-24 Jonathan Braden , Matthew C. Johnson , Hiranya V. Peiris , Andrew Pontzen , Silke Weinfurtner

We propose a scheme to realize lattice potentials of sub-wavelength spacing for ultracold atoms. It is based on spin-dependent optical lattices with a time-periodic modulation. We show that the atomic motion is well described by the…

Quantum Gases · Physics 2015-10-07 Sylvain Nascimbene , Nathan Goldman , Nigel R. Cooper , Jean Dalibard

We theoretically study the dipolar motion of bosonic atoms in a very shallow, strongly confined 1D optical lattice using the parameters of the recent experiment [Fertig et al., Phys. Rev. Lett. 94, 220402 (2005)]. We find that, due to…

Statistical Mechanics · Physics 2009-11-11 J. Ruostekoski , L. Isella

We compare the semiclassical description of NEMS within and beyond the adiabatic approximation. We consider a NEMS model which contains a single phonon (oscillator) mode linearly coupled to an electronic few-level system in contact with…

Mesoscale and Nanoscale Physics · Physics 2013-01-10 A. Metelmann , T. Brandes

We report the experimental implementation of the Dicke model in the semiclassical approximation, which describes a large number of two-level atoms interacting with a single-mode electromagnetic field in a perfectly reflecting cavity. This…