Reactive collisions in confined geometries

Ultracold atoms placed in a tight cigar-shaped trap are usually described in terms of the LiebLiniger model. We study the extensions of this model which arise when van der Waals interaction between atoms is taken into account. We find that the corrections induced by the finite range of interactions can become especially important in the vicinity of narrow Feshbach resonances and suggest realistic schemes of their experimental detection. The interplay of confinement and interactions can lead to effective transparency where the one-dimensional interactions are weak in a wide range of parameters.

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“…By solving the Schrödinger equation with the pseudopotential (6) and boundary conditions (9), we obtain [21,47] …”

Section: Atomic Scattering In a Quasi-1d Waveguidementioning

confidence: 99%

Ultracold atoms in quasi-one-dimensional traps: A step beyond the Lieb-Liniger model

et al. 2017

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“…To investigate chemical reactions between cold molecules, optical lattices are a convenient testbed as they allow for either isolating the molecules from each other or letting them collide. In addition optical lattices offer the possibility to control the dimensionality of the scattering process and to tune the interaction [35][36][37][38] . Based on this approach, it has been shown that strong inelastic collisions induce correlations and can inhibit particle loss in a molecular sample, a manifestation of the quantum Zeno effect 15,34 .In this work we present the first measurements on ultracold collisions of metastable triplet molecules that are internally in their lowest energy state.…”

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“…The description changes when reducing the dimensionality of the scattering process 35,48 . Generally, a system enters the quasi-1D regime for large trap aspect ratios ωx, ωy ωz and low enough collision energies Ecol < 2 ωx,y.…”

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confidence: 99%

“…In order to compare scaling of the 1D and 3D cases in more detail we examine the decay rates Γi = 2 Kini, where i ∈ {1D, 3D}, and n1D represents a 1D density of molecules. In the low energy limit, the ratio 35,48 where d is the transverse confinement size, as given by the harmonic oscillator length (Methods). We note that n1D/d 2 can be thought of as an equivalent 3D density of the confined system.…”

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confidence: 99%

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Inelastic collisions of ultracold triplet Rb2 molecules in the rovibrational ground state

et al. 2017

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Exploring and controlling inelastic and reactive collisions on the quantum level is a main goal of the developing field of ultracold chemistry. For this, the preparation of precisely defined initial atomic and molecular states in tailored environments is necessary. Here we present experimental studies of inelastic collisions of metastable ultracold Rb2 molecules in an array of quasi-1D potential tubes. In particular, we investigate collisions of molecules in the absolute lowest triplet energy level where any inelastic process requires a change of the electronic state. Remarkably, we find similar decay rates as for collisions between rotationally or vibrationally excited triplet molecules where other decay paths are also available. The decay rates are close to the ones for universal reactions but vary considerably when confinement and collision energy are changed. This might be exploited to control the collisional properties of molecules.

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“…Ultracold high phase-space-density gases of polar molecules in their absolute rovibrational ground state have already been produced [41][42][43][44][45] and allowed for groundbreaking experiments on controlled chemical reactions [46][47][48][49]. An unprecedented control over ultracold molecular collisions has been achieved by selecting molecules' internal states and by tuning dipolar collisions with an external electric field in a reduced dimensionality [50][51][52][53][54][55][56]. Ultracold polar molecules have been also produced in an optical lattice [57], and dipolar spin-exchange interactions between lattice-confined polar molecules have been observed [58], opening the way towards quantum simulations with molecules [59].…”

Section: Introductionmentioning

confidence: 99%

Two interacting ultracold molecules in a one-dimensional harmonic trap

2018

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We investigate the properties of two interacting ultracold polar molecules described as distinguishable quantum rigid rotors, trapped in a one-dimensional harmonic potential. The molecules interact via a multichannel two-body contact potential, incorporating the short-range anisotropy of intermolecular interactions including dipole-dipole interaction. The impact of external electric and magnetic fields resulting in Stark and Zeeman shifts of molecular rovibrational states is also investigated. Energy spectra and eigenstates are calculated by means of the exact diagonalization. The importance and interplay of the molecular rotational structure, anisotropic interactions, spin-rotation coupling, electric and magnetic fields, and harmonic trapping potential are examined in detail, and compared to the system of two harmonically trapped distinguishable atoms. The presented model and results may provide microscopic parameters for molecular many-body Hamiltonians, and may be useful for the development of bottom-up molecule-by-molecule assembled molecular quantum simulators.

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Reactive collisions in confined geometries

Cited by 21 publications

References 42 publications

Ultracold atoms in quasi-one-dimensional traps: A step beyond the Lieb-Liniger model

Ultracold atoms in quasi-one-dimensional traps: A step beyond the Lieb-Liniger model

Inelastic collisions of ultracold triplet Rb2 molecules in the rovibrational ground state

Two interacting ultracold molecules in a one-dimensional harmonic trap

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