Interaction-driven Lifshitz transition with dipolar fermions in optical lattices

Loon, Erik G. C. P. van; Katsnelson, M. I.; Chomaz, Lauriane; Lemeshko, Mikhail

doi:10.1103/physrevb.93.195145

Cited by 8 publications

(7 citation statements)

References 119 publications

(138 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ground-state [39,40] and the dynamic properties of such systems have been systematically investigated theoretically and numerically in the collisionless regime [41][42][43], in the hydrodynamic regime [44,45], as well as in the whole collisional range from one limiting case to the other [46,47]. The FS deformation was also recently theoretically studied in mixtures of dipolar and non-dipolar fermions [48], as well as in the presence of a weak lattice confinement [49].…”

Section: Introductionmentioning

confidence: 99%

Ground state of an ultracold Fermi gas of tilted dipoles in elongated traps

et al. 2018

View full text Add to dashboard Cite

Many-body dipolar effects in Fermi gases are quite subtle as they energetically compete with the large kinetic energy at and below the Fermi surface (FS). Recently it was experimentally observed in a sample of erbium atoms that its FS is deformed from a sphere to an ellipsoid due to the presence of the anisotropic and long-range dipole-dipole interaction Aikawa et al (2014 Science 345 1484). Moreover, it was suggested that, when the dipoles are rotated by means of an external field, the FS follows their rotation, thereby keeping the major axis of the momentum-space ellipsoid parallel to the dipoles. Here we generalise a previous Hartree-Fock mean-field theory to systems confined in an elongated triaxial trap with an arbitrary orientation of the dipoles relative to the trap. With this we study for the first time the effects of the dipoles' arbitrary orientation on the ground-state properties of the system. Furthermore, taking into account the geometry of the system, we show how the ellipsoidal FS deformation can be reconstructed, assuming ballistic expansion, from the experimentally measurable real-space aspect ratio after a free expansion. We compare our theoretical results with new experimental data measured with erbium Fermi gas for various trap parameters and dipole orientations. The observed remarkable agreement demonstrates the ability of our model to capture the full angular dependence of the FS deformation. Moreover, for systems with even higher dipole moment, our theory predicts an additional unexpected effect: the FS does not simply follow rigidly the orientation of the dipoles, but softens showing a change in the aspect ratio depending on the dipoles' orientation relative to the trap geometry, as well as on the trap anisotropy itself. Our theory provides the basis for understanding and interpreting phenomena in which the investigated physics depends on the underlying structure of the FS, such as fermionic pairing and superfluidity.

show abstract

Section: Introductionmentioning

confidence: 99%

Ground state of an ultracold Fermi gas of tilted dipoles in elongated traps

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Additionally, p-wave superfluidity may arise. The interplay between lattice and dipole-induced Fermi surface deformation has also been predicted to yield a topological phase transition, of a Lifshiftz type [731]. Of even larger interest has been a case recovering a situation closer to the bosonic model, with (effective) spin-1/2 fermions as for the conventional Hubbard model; see Eq.…”

Section: Extended Hubbard Hamiltonian and Consequencesmentioning

confidence: 99%

“…( 77) cancels, only retaining the tunnelling and NNI terms. Theoretically, this case is also of interest, yet turns out to be more complicated to treat than the boson one [14,144,[726][727][728][729][730][731]. Few studies have shown that various kinds of charge-density-wave and supersolid phases also forms in dipolar fermions lattice systems in 2D [726][727][728][729] and 3D [730].…”

Section: Extended Hubbard Hamiltonian and Consequencesmentioning

confidence: 99%

Dipolar physics: A review of experiments with magnetic quantum gases

Chomaz¹,

Ferrier-Barbut²,

Ferlaino³

et al. 2022

Preprint

View full text Add to dashboard Cite

“…For spinless fermions, a similar expression equation ( 77) can also be derived, yet because of the Pauli exclusion principle, the second and fourth terms of the sum in equation ( 77) cancels, only retaining the tunnelling and NNI terms. Theoretically, this case is also of interest, yet turns out to be more complicated to treat than the boson one [13,146,[739][740][741][742][743][744][745]. Few studies have shown that various kinds of charge-density-wave and SSPs also forms in dipolar fermions lattice systems in 2D [739][740][741][742]744] and 3D [743].…”

Section: Extended Hubbard Hamiltonian and Consequencesmentioning

confidence: 99%

Dipolar physics: a review of experiments with magnetic quantum gases

et al. 2022

View full text Add to dashboard Cite

Since the achievement of quantum degeneracy in gases of chromium atoms in 2004, the experimental investigation of ultracold gases made of highly magnetic atoms has blossomed. The field has yielded the observation of many unprecedented phenomena, in particular those in which long-range and anisotropic dipole-dipole interactions play a crucial role. In this review, we aim to present the aspects of the magnetic quantum-gas platform that make it unique for exploring ultracold and quantum physics as well as to give a thorough overview of experimental achievements. Highly magnetic atoms distinguish themselves by the fact that their electronic ground-state configuration possesses a large spin (as well as a large $g$ factor). This results in a large magnetic moment and a rich electronic transition spectrum. Such transitions are useful for cooling, trapping, and manipulating these atoms. The complex atomic structure and large dipolar moments of these atoms also lead to a dense spectrum of resonances in their two-body scattering behaviour. These resonances can be used to control the interatomic interactions and, in particular, the relative importance of contact over dipolar interactions. These features provide exquisite control knobs for exploring the few- and many-body physics of dipolar quantum gases. The study of dipolar effects in magnetic quantum gases has covered various few-body phenomena that are based on elastic and inelastic anisotropic scattering. Various many-body effects have also been demonstrated. These affect both the shape, stability, dynamics, and excitations of fully polarised repulsive Bose or Fermi gases. Beyond the mean-field instability, strong dipolar interactions competing with slightly weaker contact interactions between magnetic bosons yield new quantum-stabilised states, among which are self-bound droplets, droplet assemblies, and supersolids. Dipolar interactions also deeply affect the physics of atomic gases with an internal degree of freedom as these interactions intrinsically couple spin and atomic motion. Finally, long-range dipolar interactions can stabilise strongly correlated excited states of 1D gases and also impact the physics of lattice-confined systems, both at the spin-polarised level (Hubbard models with off-site interactions) and at the spinful level (XYZ models). In the present manuscript, we aim to provide an extensive overview of the various related experimental achievements up to the present.

show abstract

Interaction-driven Lifshitz transition with dipolar fermions in optical lattices

Cited by 8 publications

References 119 publications

Ground state of an ultracold Fermi gas of tilted dipoles in elongated traps

Ground state of an ultracold Fermi gas of tilted dipoles in elongated traps

Dipolar physics: A review of experiments with magnetic quantum gases

Dipolar physics: a review of experiments with magnetic quantum gases

Contact Info

Product

Resources

About