We suggest an experimentally feasible procedure to observe counterflow and paired superfluidity i... more We suggest an experimentally feasible procedure to observe counterflow and paired superfluidity in ultra-cold atom systems. We study the time evolution of one-dimensional mixtures of bosonic atoms in an optical lattice following an abrupt displacement of an additional weak confining potential. We find that the dynamic responses of the paired superfluid phase for attractive inter-species interactions and the counterflow superfluid phase for repulsive interactions are qualitatively distinct and reflect the quasi long-range order that characterizes these phases. These findings suggest a clear experimental procedure for their detection, and give an intuitive insight into their dynamics.
Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmon... more Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmonic trap by employing a magnetic field sweep across a Feshbach resonance followed by stimulated Raman adiabatic passage [K.-K. Ni et al., Science 322, 231 ]. The overall experimental efficiency for molecule formation was around 20%. We show that the efficiency can be increased to nearly 100% if one first loads the atomic gases into an optical lattice of the appropriate depth and tunes the interspecies attraction to have exactly one atom of each species at an occupied lattice site. Our proposed scheme provides a large enhancement to the dipolar molecule density even at relatively high temperatures, and avoids three-body recombination loss by preventing lattice sites from being triply occupied.
APS Bulletin of the American Physical Society. 41st Annual Meeting of the APS Division of Atomic,... more APS Bulletin of the American Physical Society. 41st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics Volume 55, Number 5. Tuesday–Saturday, May 25–29, 2010; Houston, Texas. ...
We study binary bosonic mixtures of ultra-cold atoms, confined to one dimension in an optical lat... more We study binary bosonic mixtures of ultra-cold atoms, confined to one dimension in an optical lattice, for various densities. Within a Luttinger liquid description, using renormalization group equations at second order, we determine both ordered and quasi-ordered phases of these mixtures. At commensurate filling, eg unit-filling and half-filling, we find different types of localized phases, whereas for densities that are incommensurate to the lattice, but equal for the two species, we find the behavior of a spin gap transition. We ...
Physica A: Statistical Mechanics and its …, Jan 1, 2006
By using the concept of negativity, we investigate entanglement in (12, 1) mixed-spin Heisenberg ... more By using the concept of negativity, we investigate entanglement in (12, 1) mixed-spin Heisenberg systems. We obtain the analytical results of entanglement in small isotropic Heisenberg clusters with only nearest-neighbor (NN) interactions up to four spins and in the four-spin Heisenberg model with both NN and next-nearest-neighbor (NNN) interactions. For more spins, we numerically study effects of temperature, magnetic fields, and NNN interactions on entanglement. We study in detail the threshold value of the temperature, ...
We study the noise correlations of one-dimensional (1D) Bose mixtures, as a probe of their quantu... more We study the noise correlations of one-dimensional (1D) Bose mixtures, as a probe of their quantum phases. In [1], we discuss the rich structure of many-body phases, such as paired and counterflow superfluidity in such 1D mixtures. We now ask the question what is the signature of these phases in the correlations of the atomic cloud after time-of-flight at long times. Using both Luttinger liquid theory and time-evolving block decimation (TEBD) method, we find clear signatures of these phases. Within the numerical approach we also discuss ...
Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmon... more Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmonic trap by employing a magnetic field sweep across a Feshbach resonance followed by stimulated Raman adiabatic passage [K.-K. Ni et al., Science 322, 231 ]. The overall experimental efficiency for molecule formation was around 20%. We show that the efficiency can be increased to nearly 100% if one first loads the atomic gases into an optical lattice of the appropriate depth and tunes the interspecies attraction to have exactly one atom of each species at an occupied lattice site. Our proposed scheme provides a large enhancement to the dipolar molecule density even at relatively high temperatures, and avoids three-body recombination loss by preventing lattice sites from being triply occupied.
Two models are discussed here to illustrate the quantum many-body phenomena in mixtures of ultra-... more Two models are discussed here to illustrate the quantum many-body phenomena in mixtures of ultra-cold atoms in optical lattices. The first model describes a mixture of two species of bosonic atoms of equal masses in optical lattices and the second describes a mixture of heavy bosonic atoms and light fermionic atoms in optical lattices. For both models, we assume the trap is present and use parameters typical in experiment.
We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of gr... more We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of ground-state pairwise entanglement for the four-qubit model by identifying a Z2 symmetry. Although the entanglements cannot identify the critical point of the system, the mean entanglement of nearest-neighbor qubits really does, namely, it reaches a maximum at the critical point.
We suggest an experimentally feasible procedure to observe counterflow and paired superfluidity i... more We suggest an experimentally feasible procedure to observe counterflow and paired superfluidity in ultra-cold atom systems. We study the time evolution of one-dimensional mixtures of bosonic atoms in an optical lattice following an abrupt displacement of an additional weak confining potential. We find that the dynamic responses of the paired superfluid phase for attractive inter-species interactions and the counterflow superfluid phase for repulsive interactions are qualitatively distinct and reflect the quasi long-range order that characterizes these phases. These findings suggest a clear experimental procedure for their detection, and give an intuitive insight into their dynamics.
Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmon... more Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmonic trap by employing a magnetic field sweep across a Feshbach resonance followed by stimulated Raman adiabatic passage [K.-K. Ni et al., Science 322, 231 ]. The overall experimental efficiency for molecule formation was around 20%. We show that the efficiency can be increased to nearly 100% if one first loads the atomic gases into an optical lattice of the appropriate depth and tunes the interspecies attraction to have exactly one atom of each species at an occupied lattice site. Our proposed scheme provides a large enhancement to the dipolar molecule density even at relatively high temperatures, and avoids three-body recombination loss by preventing lattice sites from being triply occupied.
APS Bulletin of the American Physical Society. 41st Annual Meeting of the APS Division of Atomic,... more APS Bulletin of the American Physical Society. 41st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics Volume 55, Number 5. Tuesday–Saturday, May 25–29, 2010; Houston, Texas. ...
We study binary bosonic mixtures of ultra-cold atoms, confined to one dimension in an optical lat... more We study binary bosonic mixtures of ultra-cold atoms, confined to one dimension in an optical lattice, for various densities. Within a Luttinger liquid description, using renormalization group equations at second order, we determine both ordered and quasi-ordered phases of these mixtures. At commensurate filling, eg unit-filling and half-filling, we find different types of localized phases, whereas for densities that are incommensurate to the lattice, but equal for the two species, we find the behavior of a spin gap transition. We ...
Physica A: Statistical Mechanics and its …, Jan 1, 2006
By using the concept of negativity, we investigate entanglement in (12, 1) mixed-spin Heisenberg ... more By using the concept of negativity, we investigate entanglement in (12, 1) mixed-spin Heisenberg systems. We obtain the analytical results of entanglement in small isotropic Heisenberg clusters with only nearest-neighbor (NN) interactions up to four spins and in the four-spin Heisenberg model with both NN and next-nearest-neighbor (NNN) interactions. For more spins, we numerically study effects of temperature, magnetic fields, and NNN interactions on entanglement. We study in detail the threshold value of the temperature, ...
We study the noise correlations of one-dimensional (1D) Bose mixtures, as a probe of their quantu... more We study the noise correlations of one-dimensional (1D) Bose mixtures, as a probe of their quantum phases. In [1], we discuss the rich structure of many-body phases, such as paired and counterflow superfluidity in such 1D mixtures. We now ask the question what is the signature of these phases in the correlations of the atomic cloud after time-of-flight at long times. Using both Luttinger liquid theory and time-evolving block decimation (TEBD) method, we find clear signatures of these phases. Within the numerical approach we also discuss ...
Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmon... more Ultracold ground state dipolar 40 K 87 Rb molecules have recently been produced in a loose harmonic trap by employing a magnetic field sweep across a Feshbach resonance followed by stimulated Raman adiabatic passage [K.-K. Ni et al., Science 322, 231 ]. The overall experimental efficiency for molecule formation was around 20%. We show that the efficiency can be increased to nearly 100% if one first loads the atomic gases into an optical lattice of the appropriate depth and tunes the interspecies attraction to have exactly one atom of each species at an occupied lattice site. Our proposed scheme provides a large enhancement to the dipolar molecule density even at relatively high temperatures, and avoids three-body recombination loss by preventing lattice sites from being triply occupied.
Two models are discussed here to illustrate the quantum many-body phenomena in mixtures of ultra-... more Two models are discussed here to illustrate the quantum many-body phenomena in mixtures of ultra-cold atoms in optical lattices. The first model describes a mixture of two species of bosonic atoms of equal masses in optical lattices and the second describes a mixture of heavy bosonic atoms and light fermionic atoms in optical lattices. For both models, we assume the trap is present and use parameters typical in experiment.
We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of gr... more We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of ground-state pairwise entanglement for the four-qubit model by identifying a Z2 symmetry. Although the entanglements cannot identify the critical point of the system, the mean entanglement of nearest-neighbor qubits really does, namely, it reaches a maximum at the critical point.
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