Optical Lattice Experiment

Our work on studying the quantum criticality and Tomonaga-Luttinger liquid is now published on Phys. Rev. Lett..

It has been highlighted as Editors' Suggestion. See viewpoint by Thierry Giamarchi, from University of Geneva, Switzerland: "Theory for 1D Quantum Materials Tested with Cold Atoms and Superconductors".


One-dimensional (1D) materials—from nanowires to carbon nanotubes to linear arrays of cold atoms—hold promise for applications in nanoelectronics, sensing, energy harvesting, and quantum information processing. They are also ideal for exploring fundamental quantum phenomena at the nanoscale. Their theoretical description relies on a model known as the Tomonaga-Luttinger liquid (TLL), which can account for the many-body interactions within a 1D ensemble of quantum systems (fermions, spins, or bosons). To date, however, only a few of the aspects of this theory have been experimentally tested. This is mostly due to the difficulty of realizing an ideal and controllable 1D system experimentally. ...

Ring-exchange interactions are basic elements needed for realizing topological quantum computation. These interactions and anyonic statistics have been engineered using ultracold atoms in an optical lattice.

A preprint article is online at Nature Physics now.

We experimentally investigate the quantum criticality and Tomonaga-Luttinger liquid (TLL) behavior within one-dimensional (1D) ultracold ⁸⁷Rb atoms. Based on the measured density profile at different temperatures, the universal scaling laws of thermodynamic quantities are observed. The quantum critical regime and the relevant crossover temperatures are determined through the double-peak structure of the specific heat. In the TLL regime, we obtain the Luttinger parameter by probing sound propagation. Furthermore, a characteristic power-law behavior emerges in the measured momentum distributions of the 1D ultracold gas, confirming the existence of the TLL.

A preprint article is on arXiv now.

Klaus Kades is going to join the group for his Master thesis! Welcome!

Congratulations to Andreas Reingruber for his sucessfull thesis defense! His thesis is about the work on the lattice project, with title of "Two- and four-body spin-exchange processes in optical lattices".

Hui Sun from QPQI (USTC, Hefei) is going to join the lattice team with the CSC fellowship!

Nature Physics (2016), Published online 21 March 2016, doi:10.1038/nphys3705

Ring-exchange interactions between spins are experimental observed in a four-site optical plaquette created by a two-dimensional spin-dependent superlattice. A minimum instance of the Kitaev's toric code is simulated, and the anyonic statistics between its elementary excitations are observed. A preprint article is on arXiv now.

Yong-Guang Zheng from QPQI (USTC, Hefei) is going to join the lattice team for the next three months! Welcome!

Hui Sun from QPQI (USTC, Hefei) is going to join the lattice team for the next three months! Welcome!

Bing Yang from the Lattice Group has succefully defended his thesis at Shanghai. Congratulations!

Reference:
Bing Yang, Experimental study on spin entanglement with ultracold atoms in optical lattices.

Spin-spin correlations are measured via the collisional atom loss with in situ absorption imaging, and therefore the entanglement is measured. A preprint article is on arXiv now.

Time resloved oscilations driven by super-exchange interaction in isolated superlattice wells are observed. Strong dephasing by transversal inhomogeneity are analyzed with insitu imaging methods.

After a sucessfull thesis defense Torsten Mandel and Xiao-Fan Xu from the Cold-Atom team obtain their PhD degrees. Congratulations!

Reference:
Xiao-Fan Xu, Manipulating quantum entanglement with atomic ensembles and with atoms in optical superlattices : towards scalable quantum information processing.
Torsten Mandel, Quantum manipulation of (ultra-)cold atom systems for information processing.

After a sucessfull thesis defense Han-Ning from the Cold-Atom team obtain their PhD degrees. Congratulations!

Reference:
Han-Ning Dai, Quantum Information Processing with Cold Atoms.

Lab moving from Philosphenweg to Im Neuenheimer Feld. System recovery is now under processing!

A Bose-Einstein condensate of ⁸⁷Rb was reached in lattice lab!