We present a cluster mean-field study for ground-state phase diagram and many-body dynamics of spin-1 bosons confined in a two-chain Bose-Hubbard ladder(BHL).For unbiased BHL,we find superfluid(SF)phase and integer fi...We present a cluster mean-field study for ground-state phase diagram and many-body dynamics of spin-1 bosons confined in a two-chain Bose-Hubbard ladder(BHL).For unbiased BHL,we find superfluid(SF)phase and integer filling Mott insulator(Int MI)phase.For biased BHL,in addition to the SF and Int MI phases,there appears half-integer filling Mott insulator(HInt MI)phase.The phase transition between the SF and Int MI phases can be first order at a part of phase boundaries,while the phase transition between the SF and HInt MI phases is always second order.By tuning the bias energy,we report on the change of the nature of SF-MI phase transitions.Furthermore,we study the effect of the spin-dependent interaction on the many-body population dynamics.The spin-dependent interaction can lead to rich dynamical behaviors,but does not influence the particle transfer efficiency.Our results indicate a way to tune the nature of the SF-MI phase transition and open a new avenue to study the many-body dynamics of spinor bosons in optical lattices.展开更多
We study the topological properties of Bogoliubov excitation modes in a Bose–Hubbard model of three-dimensional（3 D） hyperhoneycomb lattices. For the non-interacting case, there exist nodal loop excitations in the ...We study the topological properties of Bogoliubov excitation modes in a Bose–Hubbard model of three-dimensional（3 D） hyperhoneycomb lattices. For the non-interacting case, there exist nodal loop excitations in the Bloch bands. As the on-site repulsive interaction increases, the system is first driven into the superfluid phase and then into the Mott-insulator phase. In both phases, the excitation bands exhibit robust nodal-loop structures and bosonic surface states. From a topology point of view, these nodal-loop excitation modes may be viewed as a permanent fingerprint left in the Bloch bands.展开更多
The symmetric and the asymmetric double-chain Bose-Hubbard Models( BHMs) are studied by the mean-field theory. By using Landau's quantum phase transition theory,phase diagrams for systems with different hopping en...The symmetric and the asymmetric double-chain Bose-Hubbard Models( BHMs) are studied by the mean-field theory. By using Landau's quantum phase transition theory,phase diagrams for systems with different hopping energies and repulsive interactions are obtained. Thereby,Mott-insulator-superfluid( MISF)phase transition boundaries are determined. Our results show that tunneling effects between two chains provide additional channels for particles hopping between corresponding optical lattice sites of different chains,which makes easier for systems to transit from MI to SF phase. The two-site parity function is also utilized to investigate the properties of the system near the quantum phase transit point.We found that the increase of inter-chain hopping will reinforce the tunneling effects between two chains,and reduce the intrachain tunneling effects within the same chain.展开更多
The phase diagram of the one-dimensional Bose-Hubbard model describing interacting bosons in optical lattice is investigated with the variational approach. This method can also be generalized to the two-dimensional case.
Higgs type excitations are the excitations which give mass to particles.The Higgs type excitations has a critical role both in particle physics and condensed matter physics.In particle physics,the suspected Higgs boso...Higgs type excitations are the excitations which give mass to particles.The Higgs type excitations has a critical role both in particle physics and condensed matter physics.In particle physics,the suspected Higgs boson has been found by the Large Hadron Collider(LHC)in 2012.In condensed matter physics,the Higgs type excitations relate to order phase of the system.In this review,we present an overview of recent studies on the Higgs type excitations both in non-interacting and interacting cold atom systems.First,in non-interacting cold atom system,by synthesizing artificial non-Abelian gauge potential,we demonstrate that when a nonAbelian gauge potential is reduced to Abelian potential,the Abelian part constructs spin-orbit coupling,and the non-Abelian part emerges Higgs excitations.Secondly,the Higgs excitations which are the reputed Higgs amplitude mode in interacting cold atom system are discussed.We review the theoretical model and the experimental detection of Higgs amplitude mode in two dimensional superfluid.The observation of both Higgs type excitations in real experiments are also discussed.展开更多
Critical temperature and condensate fraction of Bose-Einstein condensation in the optical lattice are studied. The results show that the critical temperature in optical lattices can be characterized with an equivalent...Critical temperature and condensate fraction of Bose-Einstein condensation in the optical lattice are studied. The results show that the critical temperature in optical lattices can be characterized with an equivalent critical temperature in a single lattice, which provide a fast evaluation of critical temperature and condensate fraction of Bose-Einstein condensation confined with pure optical trap. Critical temperature can be estimated with an equivalent critical temperature. It is predicted that critical temperature is proportional to q in q number lattices for superfluid state and should be equal to that in a single lattic for Mott insulate state. Required potential depth or Rabi frequency and maximum atom number in the lattices both for superfluid state and Mott state are presented based on views of thermal mechanical statistics.展开更多
基金Project supported by the Key-Area Research and Development Program of Guang Dong Province,China(Grant No.2019B030330001)the National Natural Science Foundation of China(Grant Nos.11874434 and 11574405)+1 种基金the Science and Technology Program of Guangzhou,China(Grant No.201904020024)the Guangzhou Science and Technology Projects(Grant No.202002030459)。
文摘We present a cluster mean-field study for ground-state phase diagram and many-body dynamics of spin-1 bosons confined in a two-chain Bose-Hubbard ladder(BHL).For unbiased BHL,we find superfluid(SF)phase and integer filling Mott insulator(Int MI)phase.For biased BHL,in addition to the SF and Int MI phases,there appears half-integer filling Mott insulator(HInt MI)phase.The phase transition between the SF and Int MI phases can be first order at a part of phase boundaries,while the phase transition between the SF and HInt MI phases is always second order.By tuning the bias energy,we report on the change of the nature of SF-MI phase transitions.Furthermore,we study the effect of the spin-dependent interaction on the many-body population dynamics.The spin-dependent interaction can lead to rich dynamical behaviors,but does not influence the particle transfer efficiency.Our results indicate a way to tune the nature of the SF-MI phase transition and open a new avenue to study the many-body dynamics of spinor bosons in optical lattices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474025,11674026,and 11504285)Specialized Research Fund for the Doctoral Program,ChinaYoung Talent Fund of University Association for Science and Technology in Shaanxi,China(Grant No.20160224)
文摘We study the topological properties of Bogoliubov excitation modes in a Bose–Hubbard model of three-dimensional（3 D） hyperhoneycomb lattices. For the non-interacting case, there exist nodal loop excitations in the Bloch bands. As the on-site repulsive interaction increases, the system is first driven into the superfluid phase and then into the Mott-insulator phase. In both phases, the excitation bands exhibit robust nodal-loop structures and bosonic surface states. From a topology point of view, these nodal-loop excitation modes may be viewed as a permanent fingerprint left in the Bloch bands.
基金Sponsored by the National Natural Science Foundation China(Grant No.11504106)the Special Foundation for Theoretical Physics Research Program of China(Grant No.11447167)
文摘The symmetric and the asymmetric double-chain Bose-Hubbard Models( BHMs) are studied by the mean-field theory. By using Landau's quantum phase transition theory,phase diagrams for systems with different hopping energies and repulsive interactions are obtained. Thereby,Mott-insulator-superfluid( MISF)phase transition boundaries are determined. Our results show that tunneling effects between two chains provide additional channels for particles hopping between corresponding optical lattice sites of different chains,which makes easier for systems to transit from MI to SF phase. The two-site parity function is also utilized to investigate the properties of the system near the quantum phase transit point.We found that the increase of inter-chain hopping will reinforce the tunneling effects between two chains,and reduce the intrachain tunneling effects within the same chain.
文摘The phase diagram of the one-dimensional Bose-Hubbard model describing interacting bosons in optical lattice is investigated with the variational approach. This method can also be generalized to the two-dimensional case.
基金supported by the NKBRSFC(Grant Nos.2011CB921502 and2012CB821305)National Natural Science Foundation of China(Grant Nos.61227902 and 61378017)
文摘Higgs type excitations are the excitations which give mass to particles.The Higgs type excitations has a critical role both in particle physics and condensed matter physics.In particle physics,the suspected Higgs boson has been found by the Large Hadron Collider(LHC)in 2012.In condensed matter physics,the Higgs type excitations relate to order phase of the system.In this review,we present an overview of recent studies on the Higgs type excitations both in non-interacting and interacting cold atom systems.First,in non-interacting cold atom system,by synthesizing artificial non-Abelian gauge potential,we demonstrate that when a nonAbelian gauge potential is reduced to Abelian potential,the Abelian part constructs spin-orbit coupling,and the non-Abelian part emerges Higgs excitations.Secondly,the Higgs excitations which are the reputed Higgs amplitude mode in interacting cold atom system are discussed.We review the theoretical model and the experimental detection of Higgs amplitude mode in two dimensional superfluid.The observation of both Higgs type excitations in real experiments are also discussed.
文摘Critical temperature and condensate fraction of Bose-Einstein condensation in the optical lattice are studied. The results show that the critical temperature in optical lattices can be characterized with an equivalent critical temperature in a single lattice, which provide a fast evaluation of critical temperature and condensate fraction of Bose-Einstein condensation confined with pure optical trap. Critical temperature can be estimated with an equivalent critical temperature. It is predicted that critical temperature is proportional to q in q number lattices for superfluid state and should be equal to that in a single lattic for Mott insulate state. Required potential depth or Rabi frequency and maximum atom number in the lattices both for superfluid state and Mott state are presented based on views of thermal mechanical statistics.
