This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose-Einstein condensate. It discusses...This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose-Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser.展开更多
We investigate the ground-state phases and spin textures of spin-orbit-coupled dipolar pseudo-spin-1/2 Bose-Einstein condensates in a rotating two-dimensional toroidal potential.The combined effects of dipole-dipole i...We investigate the ground-state phases and spin textures of spin-orbit-coupled dipolar pseudo-spin-1/2 Bose-Einstein condensates in a rotating two-dimensional toroidal potential.The combined effects of dipole-dipole interaction(DDI),spin-orbit coupling(SOC),rotation,and interatomic interactions on the ground-state structures and topological defects of the system are analyzed systematically.For fixed SOC strength and rotation frequency,we provide a set of phase diagrams as a function of the DDI strength and the ratio between inter-and intra-species interactions.The system can show rich quantum phases including a half-quantum vortex,symmetrical(asymmetrical)phase with quantum droplets(QDs),asymmetrical segregated phase with hidden vortices(ASH phase),annular condensates with giant vortices,triangular(square)vortex lattice with QDs,and criss-cross vortex string lattice,depending on the competition between DDI and contact interaction.For given DDI strength and rotation frequency,the increase of the SOC strength leads to a structural phase transition from an ASH phase to a tetragonal vortex lattice then to a pentagonal vortex lattice and finally to a vortex necklace,which is also demonstrated by the momentum distributions.Without rotation,the interplay of DDI and SOC may result in the formation of a unique trumpet-shaped Bloch domain wall.In addition,the rotation effect is discussed.Furthermore,the system supports exotic topological excitations,such as a half-skyrmion(meron)string,triangular skyrmion lattice,skyrmion-halfskyrmion lattice,skyrmion-meron cluster,skyrmion-meron layered necklace,skyrmion-giant-skyrmion necklace lattice,and half-skyrmion-half-antiskyrmion necklace.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 10847143)the Natural Science Foundation of Shandong Province (Grant Nos Q2007A01 and Y2008A23)
文摘This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose-Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11475144 and 11047033)the Natural Science Foundation of Hebei Province,China(Grant Nos.A2019203049 and A2015203037)+2 种基金the University Science and Technology Foundation of Hebei Provincial Department of Education,China(Grant No.Z2017056)Science and Technology Plan Projects of Tangshan City,China(Grant No.19130220g)Research Foundation of Yanshan University,China(Grant No.B846).
文摘We investigate the ground-state phases and spin textures of spin-orbit-coupled dipolar pseudo-spin-1/2 Bose-Einstein condensates in a rotating two-dimensional toroidal potential.The combined effects of dipole-dipole interaction(DDI),spin-orbit coupling(SOC),rotation,and interatomic interactions on the ground-state structures and topological defects of the system are analyzed systematically.For fixed SOC strength and rotation frequency,we provide a set of phase diagrams as a function of the DDI strength and the ratio between inter-and intra-species interactions.The system can show rich quantum phases including a half-quantum vortex,symmetrical(asymmetrical)phase with quantum droplets(QDs),asymmetrical segregated phase with hidden vortices(ASH phase),annular condensates with giant vortices,triangular(square)vortex lattice with QDs,and criss-cross vortex string lattice,depending on the competition between DDI and contact interaction.For given DDI strength and rotation frequency,the increase of the SOC strength leads to a structural phase transition from an ASH phase to a tetragonal vortex lattice then to a pentagonal vortex lattice and finally to a vortex necklace,which is also demonstrated by the momentum distributions.Without rotation,the interplay of DDI and SOC may result in the formation of a unique trumpet-shaped Bloch domain wall.In addition,the rotation effect is discussed.Furthermore,the system supports exotic topological excitations,such as a half-skyrmion(meron)string,triangular skyrmion lattice,skyrmion-halfskyrmion lattice,skyrmion-meron cluster,skyrmion-meron layered necklace,skyrmion-giant-skyrmion necklace lattice,and half-skyrmion-half-antiskyrmion necklace.
