Quantum information and many body physics with cold atoms

Abstract

We review our recent theoretical advances in quantum information and many body physics with cold atoms in various external potential, such as harmonic potential, kagome optical lattice, triangular optical lattice, and honeycomb lattice. The many body physics of cold atom in harmonic potential is investigated in the frame of mean-field Gross-Pitaevskii equation. Then the quantum phase transition and strongly correlated effect of cold atoms in triangular optical lattice, and the interacting Dirac fermions on honeycomb lattice, are investigated by using cluster dynamical mean-field theory and continuous time quantum Monte Carlo method. We also study the quantum spin Hall effect in the kagome optical lattice. Observation of Bose-Einstein condensates (BECs) in gases of weakly interacting alkali-metal atoms has stimulated intensive studies of the nonlinear matter waves, where both bright and dark solitons have been observed [1][2][3] and the gap solitons are realized in a optical lattice experimentally [4,5]. Moreover, experimental realization of BECs, in which two (or more) internal states or different atoms can be populated, has stimulated great interests in vector solitons. In real experiments, both amplitude and sign of the scattering length can be modified by utilizing the Feshbach resonance. This technique provides a very promising method for the manipulation of atomic matter waves and the nonlinear excitations in BEC by tuning the interatomic interaction.With the development of the experiments, a new developing technology called optical lattices presents a highly controllable and clean system for studying strongly correlated system, in which the relevant parameter can be adjusted independently [6][7][8][9][10][11]. Optical lattices with different geometrical property can be set up by adjusting the propagation direc-*Corresponding author (email: wmliu@iphy.ac.cn) tions of laser beams, such as triangular [12], honeycomb [13] and optical lattice. The optical lattice system has gradually become a promising platform to simulate and study a lot of quantum phenomena in condensed-matter physics, because almost all parameters of the system can be well controlled.In this article, we review quantum information and many body physics with cold atoms. In Section 1, we consider the many-body physics of BEC in harmonic potential. Section 2 is devoted to investigate the quantum phase transition and strongly correlated effect of cold atoms in triangular optical lattice, and the interacting Dirac fermions on honeycomb lattice. In Section 3, we discuss the quantum spin Hall effect of cold atom in the kagome optical lattice. Finally, we summarize our results.

Recent Advances in Iron-Catalyzed Csp2–Csp2 Cross-Couplings

“…cross-coupling products were obtained in 21-67% yields, using 0.2-0.5 mol% of this iron catalyst in tetrahydrofuran at 25 °C for 12 hours. 37 In 2012, Knochel reported a simple and practical ironcatalyzed cross-coupling of N-heterocyclic chlorides and bromides with arylmagnesium reagents. 38 The addition of an ethereal cosolvent, such as diethyl ether or tert-butyl methyl ether, was essential to prevent homocoupling side reactions and led to high yields.…”

Properties of the superfluid in the disordered Bose-Hubbard model

“…By tuning the interaction strength, the system switches between two distinct phases corresponding to the two possible ground states: the delocalized superfluid (SF) and the localized Mott-insulating (MI) state [12][13][14][15][16][17]. The relatively recent innovation of synthetic materials, made possible with ultracold atomic gases, has added a vitally important tool to study many-body physics in experimental systems [6,[18][19][20][21][22][23][24]. Such systems have been used to study the SF-MI transition [25,26] including finite-temperature properties [27,28].…”

Iron complexes of a bidentate picolyl-NHC ligand: synthesis, structure and reactivity

“…[24][25][26] The first examples with anionic aryloxo-functionalized NHCs, were reported by Shen et al 27,28 Lavoie and co-workers reported the complexes with neutral imine-functionalized NHCs. 29,30 The group of Hahn and Chen reported the octahedral complexes with pyridinyl 31 and pyrimidinyl 32,33 substituted NHC respectively. Herein, we report the syntheses and structures of a series of iron complexes of a bidentate picolyl-NHC ligand, along with their reactivity including the interconversions, transmetalation, C-C bond formations, and ligand deprotonation accompanied by the dearomatization of the pyridine moiety.…”