scholarly journals Imaging the Holon string of the Hubbard model

2020 ◽  
Vol 117 (42) ◽  
pp. 26141-26144
Author(s):  
Tin-Lun Ho
Keyword(s):  
Hubbard Model ◽  
Atomic Physics ◽  
Ground State ◽  
Condensed Matter ◽  
Quantum Simulation ◽  
Condensed Matter Physics ◽  
Two Dimensional ◽  
Ground State Wavefunction ◽  
Half Filling ◽  
Strong Repulsion

It has been a long-sought goal of quantum simulation to find answers to outstanding questions in condensed-matter physics. A famous example is finding the ground state and the excitations of the two-dimensional (2D) Hubbard model with strong repulsion below half-filling. This system is a doped antiferromagnet and is of great interest because of its possible relation to high-Tcsuperconductors. Theoretically, the fermion excitations of this model are believed to split up into holons and spinons, and a moving holon is believed to leave behind it a string of “wrong” spins that mismatch with the antiferromagnetic background. Here, we show that the properties of the ground-state wavefunction and the holon excitation of the 2D Hubbard model can be revealed in unprecedented detail by using the imaging and the interference technique in atomic physics. They allow one to reveal the Marshall sign of the doped antiferromagnet. The region of wrong Marshall sign indicates the location of the holon string.

Phase diagram of cuprate high-temperature superconductors based on the optimization Monte Carlo method

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040046
Author(s):  
T. Yanagisawa ◽  
M. Miyazaki ◽  
K. Yamaji
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Wave Function ◽  
High Temperature ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
High Temperature Superconductivity ◽  
Two Dimensional ◽  
Text Model

It is important to understand the phase diagram of electronic states in the CuO2 plane to clarify the mechanism of high-temperature superconductivity. We investigate the ground state of electronic models with strong correlation by employing the optimization variational Monte Carlo method. We consider the two-dimensional Hubbard model as well as the three-band [Formula: see text]–[Formula: see text] model. We use the improved wave function that takes account of inter-site electron correlation to go beyond the Gutzwiller wave function. The ground state energy is lowered considerably, which now gives the best estimate of the ground state energy for the two-dimensional Hubbard model. The many-body effect plays an important role as an origin of spin correlation and superconductivity in correlated electron systems. We investigate the competition between the antiferromagnetic state and superconducting state by varying the Coulomb repulsion [Formula: see text], the band parameter [Formula: see text] and the electron density [Formula: see text] for the Hubbard model. We show phase diagrams that include superconducting and antiferromagnetic phases. We expect that high-temperature superconductivity occurs near the boundary between antiferromagnetic phase and superconducting one. Since the three-band [Formula: see text]–[Formula: see text] model contains many-band parameters, high-temperature superconductivity may be more likely to occur in the [Formula: see text]–[Formula: see text] model than in single-band models.

SELF-DUAL CONE ANALYSIS IN CONDENSED MATTER PHYSICS

2011 ◽  
Vol 23 (07) ◽  
pp. 749-822 ◽  
Author(s):  
TADAHIRO MIYAO
Keyword(s):  
Hilbert Space ◽  
Ground State ◽  
Condensed Matter ◽  
The Self ◽  
Physical Models ◽  
Condensed Matter Physics ◽  
Dual Cone ◽  
Operator Inequalities ◽  
The One ◽  
Phase Angles

The self-dual cone — the central object of this review — is introduced. Several operator inequalities associated with the self-dual cone are defined and mathematical properties of those are investigated. In general there are infinitely many choices of self-dual cones in a Hilbert space. Each of these lead to a distinct family of operator inequalities in the Hilbert space which enables us to analyze quantum physical models with respect to several aspects. We refer to these applications as self-dual cone analysis. The focus of this review lies on the self-dual cone analysis of models in condensed matter physics. In particular, by taking a physically proper self-dual cone, the interaction term of the Hamiltonian of the system becomes attractive from a viewpoint of our new operator inequalities. This attractive term enables us to analyze the system and various aspects of physical interest in detail. For instance, if the attractive term is ergodic, it is shown that the ground state is unique. By the uniqueness and the conservation laws, the physically symmetric state is realized as the ground state. This could be regarded as a physical order. As applications, the BCS model and the one-dimensional Fröhlich model are studied. We explain, from a viewpoint of the self-dual cone analysis, the appearance of macroscopic phase angles in the superconductors, Josephson effect and the Peierls instability.

A SINGLE HOLE IN THE TWO-DIMENSIONAL INFINITE-U HUBBARD MODEL IN AN ORBITAL MAGNETIC FIELD

1994 ◽  
Vol 08 (06) ◽  
pp. 707-725
Author(s):  
S. V. MESHKOV ◽  
J. C. ANGLÈS D'AURIAC
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Hubbard Model ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Applied Field ◽  
Monte Carlo Algorithm ◽  
Two Dimensional ◽  
Thermodynamical Properties ◽  
Single Hole

Using an original Quantum Monte Carlo algorithm, we study the thermodynamical properties of a single hole in the two-dimensional infinite-U Hubbard model at finite temperature. We investigate the energy and the spin correlators as a function of an external orbital magnetic field. This field is found to destroy the Nagaoka ferromagnetism and to induce chirality in the spin background. The applied field is partially screened by a fictitious magnetic field coming from the chirality. Our algorithm allows us to reach a temperature low enough to discuss the ground state properties of the model.

Quantum spin Hall state in cyanided dumbbell stanene

RSC Advances ◽  
2016 ◽  
Vol 6 (89) ◽  
pp. 86089-86094 ◽  
Author(s):  
Min Yuan ◽  
Wei-xiao Ji ◽  
Miao-juan Ren ◽  
Ya-ping Wang ◽  
Hui Zhao
Keyword(s):  
High Temperature ◽  
Hall Effect ◽  
Band Gap ◽  
Condensed Matter ◽  
Quantum Spin ◽  
Condensed Matter Physics ◽  
Two Dimensional ◽  
Important Goal ◽  
Quantum Spin Hall Effect ◽  
Quantum Spin Hall

Searching for two-dimensional (2D) quantum spin Hall (QSH) insulators with a large band gap, in which the Quantum spin Hall effect (QSHE) can be observed at high temperature, is an important goal for condensed matter physics researchers.

scholarly journals Systematic 1/Sstudy of the two-dimensional Hubbard model at half-filling

1994 ◽  
Vol 50 (9) ◽  
pp. 6238-6245 ◽  
Author(s):  
Andrey V. Chubukov ◽  
Karen A. Musaelian
Keyword(s):  
Hubbard Model ◽  
Two Dimensional ◽  
Half Filling
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