arXiv:1402.1859 · Physical Review X

Efimov Trimers under Strong Confinement

Jesper Levinsen, Pietro Massignan, Meera M. Parish

Published Jul 31, 2014• 27 citations

Abstract

Confined ultracold gases exhibit a baffling property: restricting the motion of the atoms causes fewer clusters to form, not more. Researchers theoretically show that strong confinement can be used to engineer more stable structures.

DOI: 10.1103/physrevx.4.031020

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arXiv:1402.1859 · Physical Review X

Efimov Trimers under Strong Confinement

Jesper Levinsen, Pietro Massignan, Meera M. Parish

Published Jul 31, 2014• 27 citations

arXiv HTML PDF

Abstract

DOI: 10.1103/physrevx.4.031020

Related papers

Forty years of Efimov physics: How a bizarre prediction turned into a hot topic

Francesca Ferlaino, Rudolf Grimm

PhysicsJan 25, 2010135 citations

Observation of an Efimov-like trimer resonance in ultracold atom–dimer scattering

Steven Knoop, Francesca Ferlaino, Manfred J. Mark +4 more

arXiv:0807.3306Nature PhysicsFeb 22, 2009233 citations

A Record Density for Laser-Cooled Molecules

Rachel J. Berkowitz

A novel laser cooling and trapping technique squeezes large numbers of molecules into a confined space while keeping them ultracold.

PhysicsMay 10, 20230 citations

Five- and Six-Body Resonances Tied to an Efimov Trimer

Javier von Stecher

We explore the properties of weakly bound bosonic states in the strongly interacting regime. Combining a correlated-Gaussian basis set expansion with a complex-scaling method, we extract the energies and structural properties of bosonic cluster states with N ≤ 6 for different two-body potentials. The identification of five- and six-body resonances attached to the first-excited-Efimov trimer provides strong support to the premise of Efimov universality in bosonic systems. Our study also reveals a rich structure of bosonic cluster states. Besides the lowest cluster states that behave as bosonic droplets, we identify cluster states weakly bound to one or two atoms forming effective cluster-atom dimers and cluster-atom-atom "trimers." The experimental signatures of these cluster states are discussed.We explore the properties of weakly bound bosonic states in the strongly interacting regime. Combining a correlated-Gaussian basis set expansion with a complex-scaling method, we extract the energies and structural properties of bosonic cluster states with N ≤ 6 for different two-body potentials. The identification of five- and six-body resonances attached to the first-excited-Efimov trimer provides strong support to the premise of Efimov universality in bosonic systems. Our study also reveals a rich structure of bosonic cluster states. Besides the lowest cluster states that behave as bosonic droplets, we identify cluster states weakly bound to one or two atoms forming effective cluster-atom dimers and cluster-atom-atom "trimers." The experimental signatures of these cluster states are discussed.

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Efimov Trimers under Strong Confinement

Jesper Levinsen, Pietro Massignan, Parish, MM

The dimensionality of a system can fundamentally impact the behavior of interacting quantum particles. Classic examples range from the fractional quantum Hall effect to high-temperature superconductivity. As a general rule, one expects confinement to favor the binding of particles. However, attractively interacting bosons apparently defy this expectation: While three identical bosons in three dimensions can support an infinite tower of Efimov trimers, only two universal trimers exist in the two-dimensional case. Here, we reveal how these two limits are connected by investigating the problem of three identical bosons confined by a harmonic potential along one direction. We show that the confinement breaks the discrete Efimov scaling symmetry and successively destroys the weakest bound trimers. However, the deepest bound trimers persist even under strong confinement. In particular, the ground-state Efimov trimer hybridizes with the two-dimensional trimers, yielding a superposition of trimer configurations that effectively involves tunneling through a short-range repulsive barrier. Our results suggest a way to use strong confinement to engineer more stable Efimov-like trimers, which have so far proved elusive.The dimensionality of a system can fundamentally impact the behavior of interacting quantum particles. Classic examples range from the fractional quantum Hall effect to high-temperature superconductivity. As a general rule, one expects confinement to favor the binding of particles. However, attractively interacting bosons apparently defy this expectation: While three identical bosons in three dimensions can support an infinite tower of Efimov trimers, only two universal trimers exist in the two-dimensional case. Here, we reveal how these two limits are connected by investigating the problem of three identical bosons confined by a harmonic potential along one direction. We show that the confinement breaks the discrete Efimov scaling symmetry and successively destroys the weakest bound trimers. However, the deepest bound trimers persist even under strong confinement. In particular, the ground-state Efimov trimer hybridizes with the two-dimensional trimers, yielding a superposition of trimer configurations that effectively involves tunneling through a short-range repulsive barrier. Our results suggest a way to use strong confinement to engineer more stable Efimov-like trimers, which have so far proved elusive.

Jul 31, 201428 citations

Long-lived trimers in a quasi-two-dimensional Fermi system

Emma Laird, Thomas Kirk, Meera M. Parish +1 more

We consider the problem of three distinguishable fermions confined to a quasi-two-dimensional (quasi-2D) geometry, where there is a strong harmonic potential in one direction. We go beyond previous theoretical work and investigate the three-body bound states (trimers) for the case where the two-body short-range interactions between fermions are unequal. Using the scattering parameters from experiments on ultracold $^{6}\mathrm{Li}$ atoms, we calculate the trimer spectrum throughout the crossover from two to three dimensions. We find that the deepest Efimov trimer in the $^{6}\mathrm{Li}$ system is unaffected by realistic quasi-2D confinements, while the first excited trimer smoothly evolves from a three-dimensional-like Efimov trimer to an extended 2D-like trimer as the attractive interactions are decreased. We furthermore compute the excited trimer wave function and quantify the stability of the trimer against decay into a dimer and an atom by determining the probability that three fermions approach each other at short distances. Our results indicate that the lifetime of the trimer can be enhanced by at least an order of magnitude in the quasi-2D geometry, thus opening the door to realizing long-lived trimers in three-component Fermi gases.We consider the problem of three distinguishable fermions confined to a quasi-two-dimensional (quasi-2D) geometry, where there is a strong harmonic potential in one direction. We go beyond previous theoretical work and investigate the three-body bound states (trimers) for the case where the two-body short-range interactions between fermions are unequal. Using the scattering parameters from experiments on ultracold $^{6}\mathrm{Li}$ atoms, we calculate the trimer spectrum throughout the crossover from two to three dimensions. We find that the deepest Efimov trimer in the $^{6}\mathrm{Li}$ system is unaffected by realistic quasi-2D confinements, while the first excited trimer smoothly evolves from a three-dimensional-like Efimov trimer to an extended 2D-like trimer as the attractive interactions are decreased. We furthermore compute the excited trimer wave function and quantify the stability of the trimer against decay into a dimer and an atom by determining the probability that three fermions approach each other at short distances. Our results indicate that the lifetime of the trimer can be enhanced by at least an order of magnitude in the quasi-2D geometry, thus opening the door to realizing long-lived trimers in three-component Fermi gases.

arXiv:1803.02529Physical Review AApr 30, 20185 citations

^{6}\mathrm{Li}

atoms, we calculate the trimer spectrum throughout the crossover from two to three dimensions. We find that the deepest Efimov trimer in the

^{6}\mathrm{Li}

system is unaffected by realistic quasi-2D confinements, while the first excited trimer smoothly evolves from a three-dimensional-like Efimov trimer to an extended 2D-like trimer as the attractive interactions are decreased. We furthermore compute the excited trimer wave function and quantify the stability of the trimer against decay into a dimer and an atom by determining the probability that three fermions approach each other at short distances. Our results indicate that the lifetime of the trimer can be enhanced by at least an order of magnitude in the quasi-2D geometry, thus opening the door to realizing long-lived trimers in three-component Fermi gases.