scholarly journals QUANTUM PHASES OF ULTRACOLD BOSONIC ATOMS IN A TWO-DIMENSIONAL OPTICAL SUPERLATTICE

2009 ◽  
Vol 23 (01) ◽  
pp. 25-33 ◽  
Author(s):  
JING-MIN HOU
Keyword(s):  
Hubbard Model ◽  
Density Wave ◽  
Noise Correlation ◽  
Two Dimensional ◽  
Quantum Phases ◽  
First Order ◽  
Optical Superlattice ◽  
Correlation Techniques ◽  
Ultracold Bosonic Atoms ◽  
Bosonic Atoms

We study quantum phases of ultracold bosonic atoms in a two-dimensional optical superlattice. The extended Bose–Hubbard model derived from the system of ultracold bosonic atoms in an optical superlattice is solved numerically with the Gutzwiller approach. We find that the modulated superfluid (MS), Mott-insulator (MI) and density-wave (DW) phases appear in some regimes of parameters. The experimental detection of the first-order correlations and the second-order correlations of different quantum phases with time-of-flight and noise-correlation techniques is proposed.

PRECURSOR OF ANTIFERROMAGNETIC BANDS IN THE HALF-FILLED TWO-DIMENSIONAL HUBBARD MODEL

1999 ◽  
Vol 13 (27) ◽  
pp. 3183-3192
Author(s):  
BUMSOO KYUNG
Keyword(s):  
Hubbard Model ◽  
Density Of States ◽  
Density Wave ◽  
Spin Density Wave ◽  
Local Maximum ◽  
Two Dimensional ◽  
Intermediate Coupling ◽  
Critical Fluctuations ◽  
Wave Approximation ◽  
Good Agreement

We study the half-filled two-dimensional Hubbard model in the intermediate coupling regime. As temperature is decreased for a two-dimensional half-filled band, two-dimensional critical fluctuations give rise to a strong local maximum in | Im Σ(k F , ω)| at ω=0, leading to a split peak with a pseudogap inside in the spectral function and the density of states. The calculated energy dispersion is in good agreement with that of spin density wave approximation.

scholarly journals Incommensurate Spin-Density Wave in Two-Dimensional Hubbard Model

2012 ◽  
Vol 190 ◽  
pp. 67-70 ◽  
Author(s):  
M.A. Timirgazin ◽  
Anatoly K. Arzhnikov ◽  
A.V. Vedyayev
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
Magnetic Phase ◽  
Density Wave ◽  
Spin Density Wave ◽  
Magnetic Phase Diagram ◽  
Two Dimensional ◽  
Magnetic Phases ◽  
Model Relation

We consider the magnetic phase diagram of the two-dimensional Hubbard model ona square lattice.We take into account both spiral and collinear incommensurate magnetic states.The possibility of phase separation of spiral magnetic phases is taken into consideration as well.Our study shows that all the listed phases appear to be the ground state at certain parametersof the model. Relation of the obtained results to real materials, e.g. Cu-based high-temperaturesuperconductors, is discussed.

Electron spectral density of the half-filled Hubbard model in the atomic limit at finite temperature

Open Physics ◽  
2003 ◽  
Vol 1 (3) ◽  
Author(s):  
Sergei Ovchinnikov ◽  
Elena Shneyder
Keyword(s):  
Low Temperature ◽  
Spectral Density ◽  
Hubbard Model ◽  
Density Wave ◽  
Spin Density Wave ◽  
Long Range Order ◽  
Two Dimensional ◽  
Similar Form ◽  
Atomic Limit ◽  
Ordered State

AbstractWe have calculated the spectral function and density of states of halffilled two-dimensional Hubbard model in the Hubbard-I approximation assuming an antiferromagnetic long range order at low temperature and compared results to the QMC data. It occurs that calculated functions are in a qualitative agreement with the QMC one. We have also shown that Neel ordered state dispersion has the similar form to the spin density wave one.

RENORMALISATION GROUP ANALYSIS OF THE TWO-DIMENSIONAL HUBBARD MODEL: SPIN CORRELATIONS AND D-WAVE SUPERCONDUCTIVITY

2003 ◽  
Vol 17 (28) ◽  
pp. 5279-5288
Author(s):  
W. METZNER
Keyword(s):  
Hubbard Model ◽  
Spin Density ◽  
Density Wave ◽  
Group Analysis ◽  
Interaction Strength ◽  
Renormalisation Group ◽  
Model Parameters ◽  
Two Dimensional ◽  
Effective Interactions ◽  
D Wave

The repulsive two-dimensional Hubbard model is analysed within a functional renormalisation group (RG) approach. The flow equation for the effective interactions is evaluated on 1-loop level. The effective interactions diverge at a finite energy scale which is exponentially small for small bare interactions. To analyse the nature of the instabilities signalled by the diverging interactions, we compute the flow of the superconducting susceptibilities for various pairing symmetries and also charge and spin density susceptibilities. Depending on the choice of the model parameters (hopping amplitudes, interaction strength and band-filling) we find spin density wave instabilities or d-wave superconductivity as leading instability close to half-filling. This calculation establishes the existence of d-wave superconductivity in the Hubbard model beyond doubt.

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