Phase Transitions in Optical Lattices at Finite Temperatures

We investigate strongly correlated spin-1 ultracold bosons with antiferromagnetic interactions in a cubic optical lattice, based on bosonic dynamical mean-field theory. Rich phase diagrams of the system are mapped out at both zero and finite temperature, and in particular the existence of a spin-singlet condensate is established. Interestingly, at finite temperature, we find that the superfluid can be heated into a Mott insulator with even (odd) filling via a first- (second-) order phase transition, analogous to the Pomeranchuk effect in $^{3}\mathrm{He}$ . Moreover, for typical experimental setups, we estimate the critical temperature (entropy) for different ordered phases and our results suggest that direct experimental observation of these phases is promising.We investigate strongly correlated spin-1 ultracold bosons with antiferromagnetic interactions in a cubic optical lattice, based on bosonic dynamical mean-field theory. Rich phase diagrams of the system are mapped out at both zero and finite temperature, and in particular the existence of a spin-singlet condensate is established. Interestingly, at finite temperature, we find that the superfluid can be heated into a Mott insulator with even (odd) filling via a first- (second-) order phase transition, analogous to the Pomeranchuk effect in $^{3}\mathrm{He}$. Moreover, for typical experimental setups, we estimate the critical temperature (entropy) for different ordered phases and our results suggest that direct experimental observation of these phases is promising.

arXiv:1507.07249Physical Review AMar 14, 201615 citations

Adiabatic cooling and heating of cold bosons in three-dimensional optical lattices and the superfluid-normal phase transition

S. Yoshimura, Satoru Konabe, Tetsuro Nikuni

We investigate effects of the adiabatic ramp-up of optical lattices to the temperatures of Bose gases. Applying the mean-field approximation to the three-dimensional Bose-Hubbard model at finite temperatures, we calculate the isentropic curves in the phase diagram against the temperatures and the lattice height. The adiabatic cooling or heating through superfluid-normal phase transition is clearly understood. It is found that the cooling occurs in superfluid phase while the heating occurs in normal phase and the efficiency of adiabatic cooling or heating is higher at higher temperatures. This behavior can be understood from the lattice-height dependence of dispersion relation in each phase. Furthermore, the connection of the adiabatic cooling or heating between the cases with and without the trap potential is addressed.We investigate effects of the adiabatic ramp-up of optical lattices to the temperatures of Bose gases. Applying the mean-field approximation to the three-dimensional Bose-Hubbard model at finite temperatures, we calculate the isentropic curves in the phase diagram against the temperatures and the lattice height. The adiabatic cooling or heating through superfluid-normal phase transition is clearly understood. It is found that the cooling occurs in superfluid phase while the heating occurs in normal phase and the efficiency of adiabatic cooling or heating is higher at higher temperatures. This behavior can be understood from the lattice-height dependence of dispersion relation in each phase. Furthermore, the connection of the adiabatic cooling or heating between the cases with and without the trap potential is addressed.

arXiv:0803.1548Physical Review AJul 30, 200810 citations

Microscopic Studies of Quantum Phase Transitions in Optical Lattices

Waseem Bakr

Dec 1, 20113 citations

QUANTUM PHASE TRANSITION OF COLD ATOMS IN OPTICAL LATTICES

Yao‐Hua Chen, Wéi Wú, Guocai Liu +1 more

Annual review of cold atoms and moleculesJan 27, 20130 citations

^{3}\mathrm{He}

. Moreover, for typical experimental setups, we estimate the critical temperature (entropy) for different ordered phases and our results suggest that direct experimental observation of these phases is promising.