scholarly journals ANDERSON LOCALIZATION VS. MOTT–HUBBARD METAL–INSULATOR TRANSITION IN DISORDERED, INTERACTING LATTICE FERMION SYSTEMS

2010 ◽  
Vol 24 (12n13) ◽  
pp. 1727-1755 ◽  
Author(s):  
Krzysztof Byczuk ◽  
Walter Hofstetter ◽  
Dieter Vollhardt
Keyword(s):  
Anderson Localization ◽  
Mean Field Theory ◽  
Mean Field ◽  
Antiferromagnetic Order ◽  
Strongly Correlated ◽  
Theoretical Understanding ◽  
Particle Correlation ◽  
Fermion Systems ◽  
Disordered Lattice ◽  
Lattice Fermion

We review recent progress in our theoretical understanding of strongly correlated fermion systems in the presence of disorder. Results were obtained by the application of a powerful nonperturbative approach, the dynamical mean-field theory (DMFT), to interacting disordered lattice fermions. In particular, we demonstrate that DMFT combined with geometric averaging over disorder can capture Anderson localization and Mott insulating phases on the level of one-particle correlation functions. Results are presented for the ground state phase diagram of the Anderson–Hubbard model at half-filling, both in the paramagnetic phase and in the presence of antiferromagnetic order. We find a new antiferromagnetic metal which is stabilized by disorder. Possible realizations of these quantum phases with ultracold fermions in optical lattices are discussed.

scholarly journals Light-induced evaporative cooling of holes in the Hubbard model

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Philipp Werner ◽  
Martin Eckstein ◽  
Markus Müller ◽  
Gil Refael
Keyword(s):  
Mean Field Theory ◽  
Evaporative Cooling ◽  
Mean Field ◽  
Hole Doping ◽  
Antiferromagnetic Order ◽  
Atomic Gases ◽  
Fermi Liquids ◽  
General Strategy ◽  
Strongly Correlated ◽  
Chirped Pulses

AbstractAn elusive goal in the field of driven quantum matter is the induction of long-range order. Here, we propose a mechanism based on light-induced evaporative cooling of holes in a correlated fermionic system. Since the entropy of a filled narrow band grows rapidly with hole doping, the isentropic transfer of holes from a doped Mott insulator to such a band results in a drop of temperature. Strongly correlated Fermi liquids and symmetry-broken states could thus be produced by dipolar excitations. Using nonequilibrium dynamical mean field theory, we show that suitably designed chirped pulses may realize this cooling effect. In particular, we demonstrate the emergence of antiferromagnetic order in a system which is initially in a weakly correlated state above the maximum Néel temperature. Our work suggests a general strategy for inducing strong correlation phenomena in periodically modulated atomic gases in optical lattices or light-driven materials.

scholarly journals ANISOTROPY IN THE COMPRESSIBLE QUANTUM HALL STATE

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1373-1376
Author(s):  
NOBUKI MAEDA
Keyword(s):  
Mean Field Theory ◽  
Density Wave ◽  
Quantum Hall ◽  
Mean Field ◽  
Dimensional System ◽  
Von Neumann ◽  
One Dimensional ◽  
Hartree Fock ◽  
Fermion Systems ◽  
Lattice Fermion

Using a mean field theory on the von Neumann lattice, we study compressible anisotropic states around ν=l+1/2 in the quantum Hall system. The Hartree-Fock energy of the unidirectional charge density wave (UCDW) are calculated self-consistently. In these states the UCDW seems to be the most plausible state. We show that the UCDW is regarded as a collection of the one-dimensional lattice fermion systems which extend to the uniform direction. The kinetic energy of this one-dimensional system is induced from the Coulomb interaction term and the self-consistent Fermi surface is obtained.

Nature of Non-magnetic Strongly-Correlated State in Plutonium

2006 ◽  
Vol 986 ◽  
Author(s):  
Leniod Purovskii ◽  
Alexander Shick ◽  
Ladislav Havela ◽  
Mikhail Katsnelson ◽  
Alexander Lichtenstein
Keyword(s):  
Field Theory ◽  
Density Functional ◽  
Local Density ◽  
Mean Field Theory ◽  
Mean Field ◽  
Dynamical Mean Field Theory ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Strongly Correlated ◽  
Starting Point

AbstractLocal density approximation for the electronic structure calculations has been highly successful for non-correlated systems. The LDA scheme quite often failed for strongly correlated materials containing transition metals and rare-earth elements with complicated charge, spin and orbital ordering. Dynamical mean field theory in combination with the first-principle scheme (LDA+DMFT) can be a starting point to go beyond static density functional approximation and include effects of charge, spin and orbital fluctuations. Ab-initio relativistic dynamical mean-field theory is applied to resolve the long-standing controversy between theory and experiment in the “simple” face-centered cubic phase of plutonium called δ-Pu. In agreement with experiment, neither static nor dynamical magnetic moments are predicted. In addition, the quasiparticle density of states reproduces not only the peak close to the Fermi level, which explains the large coefficient of electronic specific heat, but also main 5f features observed in photoelectron spectroscopy.

RECENT APPLICATIONS OF THE DMRG METHOD

2006 ◽  
Vol 20 (19) ◽  
pp. 2624-2635
Author(s):  
KAREN HALLBERG
Keyword(s):  
Degrees Of Freedom ◽  
Mean Field Theory ◽  
Mean Field ◽  
Finite Size ◽  
Strongly Correlated Systems ◽  
Strongly Correlated ◽  
Correlated Systems ◽  
Infinite Dimensional ◽  
Low Dimensional ◽  
Time Dependent Problems

Since its inception, the DMRG method has been a very powerful tool for the calculation of physical properties of low-dimensional strongly correlated systems. It has been adapted to obtain dynamical properties and to consider finite temperature, time-dependent problems, bosonic degrees of freedom, the treatment of classical problems and non-equilibrium systems, among others. We will briefly review the method and then concentrate on its latest developments, describing some recent successful applications. In particular we will show how the dynamical DMRG can be used together with the Dynamical Mean Field Theory (DMFT) to solve the associated impurity problem in the infinite-dimensional Hubbard model. This method is used to obtain spectral properties of strongly correlated systems. With this algorithm, more complex problems having a larger number of degrees of freedom can be considered and finite-size effects can be minimized.

scholarly journals Mean-field theory andεexpansion for Anderson localization

1981 ◽  
Vol 23 (6) ◽  
pp. 2640-2673 ◽  
Author(s):  
A. B. Harris ◽  
T. C. Lubensky
Keyword(s):  
Field Theory ◽  
Anderson Localization ◽  
Mean Field Theory ◽  
Mean Field

scholarly journals The valence-fluctuating ground state of plutonium

2015 ◽  
Vol 1 (6) ◽  
pp. e1500188 ◽  
Author(s):  
Marc Janoschek ◽  
Pinaki Das ◽  
Bismayan Chakrabarti ◽  
Douglas L. Abernathy ◽  
Mark D. Lumsden ◽  
...  
Keyword(s):  
Ground State ◽  
Degrees Of Freedom ◽  
Mean Field Theory ◽  
Mean Field ◽  
Complex Materials ◽  
Theoretical Understanding ◽  
Electronic Correlations ◽  
Valence Fluctuations ◽  
Electronic Configurations ◽  
Control Complex

A central issue in material science is to obtain understanding of the electronic correlations that control complex materials. Such electronic correlations frequently arise because of the competition of localized and itinerant electronic degrees of freedom. Although the respective limits of well-localized or entirely itinerant ground states are well understood, the intermediate regime that controls the functional properties of complex materials continues to challenge theoretical understanding. We have used neutron spectroscopy to investigate plutonium, which is a prototypical material at the brink between bonding and nonbonding configurations. Our study reveals that the ground state of plutonium is governed by valence fluctuations, that is, a quantum mechanical superposition of localized and itinerant electronic configurations as recently predicted by dynamical mean field theory. Our results not only resolve the long-standing controversy between experiment and theory on plutonium’s magnetism but also suggest an improved understanding of the effects of such electronic dichotomy in complex materials.

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