We investigate strongly correlated spin-1 ultracold gases with antiferromagnetic interactions in a three-dimensional optical lattice in the presence of an external magnetic field, based on bosonic dynamical mean-field theory. Due to the interplay of spin-dependent and quadratic Zeeman interactions, the system demonstrates competing magnetic orders, including nematic, spin-singlet and ferromagnetic insulating phases, depending on longitudinal magnetization. The dependence of first-order superfluid-insulator transition on external magnetic fields is explored. Interestingly, at low magnetic field, we find an abnormal multi-step condensation of the strongly correlated superfluid, i.e. the critical condensing temperature of the $m_F=-1$ component demonstrates an abnormal increase with longitudinal magnetization, in contrast to weakly interacting cases.We investigate strongly correlated spin-1 ultracold gases with antiferromagnetic interactions in a three-dimensional optical lattice in the presence of an external magnetic field, based on bosonic dynamical mean-field theory. Due to the interplay of spin-dependent and quadratic Zeeman interactions, the system demonstrates competing magnetic orders, including nematic, spin-singlet and ferromagnetic insulating phases, depending on longitudinal magnetization. The dependence of first-order superfluid-insulator transition on external magnetic fields is explored. Interestingly, at low magnetic field, we find an abnormal multi-step condensation of the strongly correlated superfluid, i.e. the critical condensing temperature of the $m_F=-1$ component demonstrates an abnormal increase with longitudinal magnetization, in contrast to weakly interacting cases.

Nov 15, 20170 citations

Two-step condensation of interacting bosons in three-dimensional isotropic harmonic traps

Ze Cheng

Abstract The Hartree–Fock–Popov theory of interacting Bose particles in a uniform space is generalized to the interacting boson system in three-dimensional isotropic harmonic traps. At finite temperature T , we find that the Bose condensation of nonideal bosons in three-dimensional isotropic harmonic traps is the two-step condensation. In other words, for a fixed particle number there are two transition temperatures. The first transition temperature is the standard critical temperature . The second transition temperature is the critical temperature , which is smaller than and is determined by the minimum of the curve of condensate fraction versus temperature. The boson system undergoes a first-order phase transition from the normal state to the Bose condensed state.Abstract The Hartree–Fock–Popov theory of interacting Bose particles in a uniform space is generalized to the interacting boson system in three-dimensional isotropic harmonic traps. At finite temperature T , we find that the Bose condensation of nonideal bosons in three-dimensional isotropic harmonic traps is the two-step condensation. In other words, for a fixed particle number there are two transition temperatures. The first transition temperature is the standard critical temperature . The second transition temperature is the critical temperature , which is smaller than and is determined by the minimum of the curve of condensate fraction versus temperature. The boson system undergoes a first-order phase transition from the normal state to the Bose condensed state.

Journal of Statistical Mechanics Theory and ExperimentNov 1, 20190 citations

Simple condensation of interacting bosons

A. Casher, M. Revzen

Annals of PhysicsJul 1, 19687 citations

Simple condensation of interacting bosons

Annals of PhysicsJun 1, 19680 citations

Pathway toward the formation of supermixed states in ultracold boson mixtures loaded in ring lattices

Andrea Richaud, Vittorio Penna

We investigate the mechanism of formation of supermixed solitonlike states in bosonic binary mixtures loaded in ring lattices. We evidence the presence of a common pathway which, irrespective of the number of lattice sites and upon variation of the interspecies attraction, leads the system from a mixed and delocalized phase to a supermixed and localized one, passing through an intermediate phase where the supermixed soliton progressively emerges. The degrees of mixing, localization, and quantum correlation of the two condensed species, quantified by means of suitable indicators commonly used in statistical thermodynamics and quantum information theory, allow one to reconstruct a bidimensional mixing-supermixing phase diagram featuring two characteristic critical lines. Our analysis is developed both within a semiclassical approach capable of capturing the essential features of the two-step mixing-demixing transition and with a fully quantum approach.We investigate the mechanism of formation of supermixed solitonlike states in bosonic binary mixtures loaded in ring lattices. We evidence the presence of a common pathway which, irrespective of the number of lattice sites and upon variation of the interspecies attraction, leads the system from a mixed and delocalized phase to a supermixed and localized one, passing through an intermediate phase where the supermixed soliton progressively emerges. The degrees of mixing, localization, and quantum correlation of the two condensed species, quantified by means of suitable indicators commonly used in statistical thermodynamics and quantum information theory, allow one to reconstruct a bidimensional mixing-supermixing phase diagram featuring two characteristic critical lines. Our analysis is developed both within a semiclassical approach capable of capturing the essential features of the two-step mixing-demixing transition and with a fully quantum approach.

arXiv:1903.09212Physical Review AJul 11, 201928 citations

m_F=-1

component demonstrates an abnormal increase with longitudinal magnetization, in contrast to weakly interacting cases.