In cold atom, the coupling between "spin" (atomic internal hyperfine states) and "orbit" (atomic center-of-mass motion) can be induced by Raman transition, where different hyperfine states are coupled by a pair of Raman lasers. In recent years, this synthetic spin-orbit coupling has received tremendous attention, as it leads to a variety of novel quantum phenomena in precisely controllable cold atom systems. In this thesis, we first present a comprehensive analysis of one-, two- and many- particle physics of harmonically trapped atoms with spin-orbit coupling, followed by the study of "novel spin-orbit coupling" in two different systems: (1) cold atom spinor mixtures and (2) cold atoms in an optical cavity. In the first system, we consider a spinor mixture consisting of two species of cold atoms, where the spin-orbit coupling can be transmitted from one species to the other, and we discuss novel topological properties and the supersolid stripe phase in this mixture. In the second system, we consider the coupling among three parts: the cavity photon field, the atomic internal hyperfine states, and the atomic external center-of-mass motion, and we discuss how this coupling affects familiar quantum optical phenomena, such as Rabi oscillation and Dicke superradiance phase transition. Our novel systems contribute new and practical platforms for the research field of synthetic spin-orbit coupling in cold atoms.In cold atom, the coupling between "spin" (atomic internal hyperfine states) and "orbit" (atomic center-of-mass motion) can be induced by Raman transition, where different hyperfine states are coupled by a pair of Raman lasers. In recent years, this synthetic spin-orbit coupling has received tremendous attention, as it leads to a variety of novel quantum phenomena in precisely controllable cold atom systems. In this thesis, we first present a comprehensive analysis of one-, two- and many- particle physics of harmonically trapped atoms with spin-orbit coupling, followed by the study of "novel spin-orbit coupling" in two different systems: (1) cold atom spinor mixtures and (2) cold atoms in an optical cavity. In the first system, we consider a spinor mixture consisting of two species of cold atoms, where the spin-orbit coupling can be transmitted from one species to the other, and we discuss novel topological properties and the supersolid stripe phase in this mixture. In the second system, we consider the coupling among three parts: the cavity photon field, the atomic internal hyperfine states, and the atomic external center-of-mass motion, and we discuss how this coupling affects familiar quantum optical phenomena, such as Rabi oscillation and Dicke superradiance phase transition. Our novel systems contribute new and practical platforms for the research field of synthetic spin-orbit coupling in cold atoms.

Jan 30, 20200 citations

Spontaneous Quantum Hall Effect in an Atomic Spinor Bose-Fermi Mixture

Zhi-Fang Xu, Xiaopeng Li, P. Zoller +1 more

We study a mixture of spin-1 bosonic and spin-1/2 fermionic cold atoms, e.g., ^{87}Rb and ^{6}Li, confined in a triangular optical lattice. With fermions at 3/4 filling, Fermi surface nesting leads to spontaneous formation of various spin textures of bosons in the ground state, such as collinear, coplanar, and even noncoplanar spin orders. The phase diagram is mapped out with varying boson tunneling and Bose-Fermi interactions. Most significantly, in one noncoplanar state the mixture is found to exhibit a spontaneous quantum Hall effect in fermions and crystalline superfluidity in bosons, both driven by interaction.We study a mixture of spin-1 bosonic and spin-1/2 fermionic cold atoms, e.g., ^{87}Rb and ^{6}Li, confined in a triangular optical lattice. With fermions at 3/4 filling, Fermi surface nesting leads to spontaneous formation of various spin textures of bosons in the ground state, such as collinear, coplanar, and even noncoplanar spin orders. The phase diagram is mapped out with varying boson tunneling and Bose-Fermi interactions. Most significantly, in one noncoplanar state the mixture is found to exhibit a spontaneous quantum Hall effect in fermions and crystalline superfluidity in bosons, both driven by interaction.

arXiv:1407.3720Physical Review LettersMar 27, 20159 citations

Relaxation and decoherence in quantum spin system

Shengjun Yuan

Jan 1, 20080 citations

Relaxation in quantum spin glasses

Bosiljka Tadić, R. Pirc, R. Blinc +1 more

Journal of Non-Crystalline SolidsSep 1, 19940 citations

Realization of a SU(2)×SU(6) System of Fermions in a Cold Atomic Gas

Shintaro Taie, Yosuke Takasu, Seiji Sugawa +4 more

We report the realization of a novel degenerate Fermi mixture with an $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ symmetry in a cold atomic gas. We successfully cool the mixture of the two fermionic isotopes of ytterbium $^{171}\mathrm{Yb}$ with the nuclear spin $I=1/2$ and $^{173}\mathrm{Yb}$ with $I=5/2$ below the Fermi temperature ${T}_{F}$ as $0.46{T}_{F}$ for $^{171}\mathrm{Yb}$ and $0.54{T}_{F}$ for $^{173}\mathrm{Yb}$ . The same scattering lengths for different spin components make this mixture featured with the novel $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ symmetry. The nuclear spin components are separately imaged by exploiting an optical Stern-Gerlach effect. In addition, the mixture is loaded into a 3D optical lattice to implement the $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ Hubbard model. This mixture will open the door to the study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like fermionic superfluid.We report the realization of a novel degenerate Fermi mixture with an $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ symmetry in a cold atomic gas. We successfully cool the mixture of the two fermionic isotopes of ytterbium $^{171}\mathrm{Yb}$ with the nuclear spin $I=1/2$ and $^{173}\mathrm{Yb}$ with $I=5/2$ below the Fermi temperature ${T}_{F}$ as $0.46{T}_{F}$ for $^{171}\mathrm{Yb}$ and $0.54{T}_{F}$ for $^{173}\mathrm{Yb}$. The same scattering lengths for different spin components make this mixture featured with the novel $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ symmetry. The nuclear spin components are separately imaged by exploiting an optical Stern-Gerlach effect. In addition, the mixture is loaded into a 3D optical lattice to implement the $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ Hubbard model. This mixture will open the door to the study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like fermionic superfluid.

arXiv:1005.3670Physical Review LettersNov 1, 2010294 citations

^{171}\mathrm{Yb}

with the nuclear spin

I=1/2

and

^{173}\mathrm{Yb}

with

I=5/2

below the Fermi temperature

{T}_{F}

0.46{T}_{F}

for

^{171}\mathrm{Yb}

and

0.54{T}_{F}

for

^{173}\mathrm{Yb}

. The same scattering lengths for different spin components make this mixture featured with the novel $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ symmetry. The nuclear spin components are separately imaged by exploiting an optical Stern-Gerlach effect. In addition, the mixture is loaded into a 3D optical lattice to implement the $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(6)$ Hubbard model. This mixture will open the door to the study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like fermionic superfluid.