We experimentally study spin dynamics in a sodium antiferromagnetic spinor condensate as a result of spin-dependent interactions $c$ and microwave dressing field interactions characterized by the net quadratic Zeeman effect ${q}_{\mathrm{net}}$ . In contrast to magnetic fields, microwave dressing fields enable us to access both negative and positive values of ${q}_{\mathrm{net}}$ . We find an experimental signature to determine the sign of ${q}_{\mathrm{net}}$ and observe harmonic spin population oscillations at every ${q}_{\mathrm{net}}$ except near each separatrix in phase space where spin oscillation period diverges. No spin domains and spatial modes are observed in our system. Our data in the negative ${q}_{\mathrm{net}}$ region exactly resembles what is predicted to occur in a ferromagnetic spinor condensate in the positive ${q}_{\mathrm{net}}$ region. This observation agrees with an important prediction derived from the mean-field theory: spin dynamics in spin-1 condensates substantially depends on the sign of ${q}_{\mathrm{net}}/c$ . This work uses only one atomic species to reveal mean-field spin dynamics, especially the remarkably different relationship between each separatrix and the magnetization, of spin-1 antiferromagnetic and ferromagnetic spinor condensates.We experimentally study spin dynamics in a sodium antiferromagnetic spinor condensate as a result of spin-dependent interactions $c$ and microwave dressing field interactions characterized by the net quadratic Zeeman effect ${q}_{\mathrm{net}}$. In contrast to magnetic fields, microwave dressing fields enable us to access both negative and positive values of ${q}_{\mathrm{net}}$. We find an experimental signature to determine the sign of ${q}_{\mathrm{net}}$ and observe harmonic spin population oscillations at every ${q}_{\mathrm{net}}$ except near each separatrix in phase space where spin oscillation period diverges. No spin domains and spatial modes are observed in our system. Our data in the negative ${q}_{\mathrm{net}}$ region exactly resembles what is predicted to occur in a ferromagnetic spinor condensate in the positive ${q}_{\mathrm{net}}$ region. This observation agrees with an important prediction derived from the mean-field theory: spin dynamics in spin-1 condensates substantially depends on the sign of ${q}_{\mathrm{net}}/c$. This work uses only one atomic species to reveal mean-field spin dynamics, especially the remarkably different relationship between each separatrix and the magnetization, of spin-1 antiferromagnetic and ferromagnetic spinor condensates.

arXiv:1310.6785Physical Review AFeb 10, 201482 citations

Phase diagram and spin mixing dynamics in spinor condensates with a microwave dressing field

Yixiao Huang, Wei Zhong, Zhe Sun +1 more

Spinor condensates immersed in a microwave dressing field, which access both negative and positive values of the net quadratic Zeeman effect, have been realized in a recent experiment. In this report, we study the ground state properties of a spinor condensate with a microwave dressing field which enables us to access both negative and positive values of quadratic Zeeman energy. The ground state exhibits three different phases by varying the magnetization and the net quadratic Zeeman energy for both cases of ferromagnetic and antiferromagnetic interactions. We investigate the atomic-number fluctuations of the ground state and show that the hyperfine state displays super-Poissonian and sub-Poissonian distributions in the different phases. We also discuss the dynamical properties and show that the separatrix has a remarkable relation to the magnetization.Spinor condensates immersed in a microwave dressing field, which access both negative and positive values of the net quadratic Zeeman effect, have been realized in a recent experiment. In this report, we study the ground state properties of a spinor condensate with a microwave dressing field which enables us to access both negative and positive values of quadratic Zeeman energy. The ground state exhibits three different phases by varying the magnetization and the net quadratic Zeeman energy for both cases of ferromagnetic and antiferromagnetic interactions. We investigate the atomic-number fluctuations of the ground state and show that the hyperfine state displays super-Poissonian and sub-Poissonian distributions in the different phases. We also discuss the dynamical properties and show that the separatrix has a remarkable relation to the magnetization.

Scientific ReportsSep 25, 20155 citations

We experimentally study spin dynamics in a sodium antiferromagnetic spinor condensate as a result of spin-dependent interactions

c

and microwave dressing field interactions characterized by the net quadratic Zeeman effect

{q}_{\mathrm{net}}

. In contrast to magnetic fields, microwave dressing fields enable us to access both negative and positive values of

{q}_{\mathrm{net}}

. We find an experimental signature to determine the sign of

{q}_{\mathrm{net}}

and observe harmonic spin population oscillations at every

{q}_{\mathrm{net}}

except near each separatrix in phase space where spin oscillation period diverges. No spin domains and spatial modes are observed in our system. Our data in the negative

{q}_{\mathrm{net}}

region exactly resembles what is predicted to occur in a ferromagnetic spinor condensate in the positive

{q}_{\mathrm{net}}

region. This observation agrees with an important prediction derived from the mean-field theory: spin dynamics in spin-1 condensates substantially depends on the sign of

{q}_{\mathrm{net}}/c

. This work uses only one atomic species to reveal mean-field spin dynamics, especially the remarkably different relationship between each separatrix and the magnetization, of spin-1 antiferromagnetic and ferromagnetic spinor condensates.