scholarly journals High harmonic generation in two-dimensional Mott insulators

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Christopher Orthodoxou ◽  
Amelle Zaïr ◽  
George H. Booth
Keyword(s):  
Quantum Monte Carlo ◽  
Strong Field ◽  
High Harmonic ◽  
Mean Field ◽  
Laser Pulses ◽  
Two Dimensions ◽  
Mott Insulators ◽  
Strongly Correlated ◽  
Two Dimensional ◽  
Mean Field Model

AbstractWith a combination of numerical methods, including quantum Monte Carlo, exact diagonalization, and a simplified dynamical mean-field model, we consider the attosecond charge dynamics of electrons induced by strong-field laser pulses in two-dimensional Mott insulators. The necessity to go beyond single-particle approaches in these strongly correlated systems has made the simulation of two-dimensional extended materials challenging, and we contrast their resulting high-harmonic emission with more widely studied one-dimensional analogues. As well as considering the photo-induced breakdown of the Mott insulating state and magnetic order, we also resolve the time and ultra-high-frequency domains of emission, which are used to characterize both the photo-transition, and the sub-cycle structure of the electron dynamics. This extends simulation capabilities and understanding of the photo-melting of these Mott insulators in two dimensions, at the frontier of attosecond non-equilibrium science of correlated materials.

Turbulent resistivity in wavy two-dimensional magnetohydrodynamic turbulence

2008 ◽  
Vol 595 ◽  
pp. 173-202 ◽  
Author(s):  
SHANE R. KEATING ◽  
P. H. DIAMOND
Keyword(s):  
Large Scale ◽  
Mean Field ◽  
Magnetic Reynolds Number ◽  
Two Dimensions ◽  
Magnetic Potential ◽  
Turbulence Theory ◽  
Two Dimensional ◽  
Restoring Force ◽  
Constrained System ◽  
Magnetohydrodynamic Turbulence

The theory of turbulent resistivity in ‘wavy’ magnetohydrodynamic turbulence in two dimensions is presented. The goal is to explore the theory of quenching of turbulent resistivity in a regime for which the mean field theory can be rigorously constructed at large magnetic Reynolds number Rm. This is achieved by extending the simple two-dimensional problem to include body forces, such as buoyancy or the Coriolis force, which convert large-scale eddies into weakly interacting dispersive waves. The turbulence-driven spatial flux of magnetic potential is calculated to fourth order in wave slope – the same order to which one usually works in wave kinetics. However, spatial transport, rather than spectral transfer, is the object here. Remarkably, adding an additional restoring force to the already tightly constrained system of high Rm magnetohydrodynamic turbulence in two dimensions can actually increase the turbulent resistivity, by admitting a spatial flux of magnetic potential which is not quenched at large Rm, although it is restricted by the conditions of applicability of weak turbulence theory. The absence of Rm-dependent quenching in this wave-interaction-driven flux is a consequence of the presence of irreversibility due to resonant nonlinear three-wave interactions, which are independent of collisional resistivity. The broader implications of this result for the theory of mean field electrodynamics are discussed.

scholarly journals Low-energy peak structure in strong-field ionization by midinfrared laser pulses: Two-dimensional focusing by the atomic potential

2012 ◽  
Vol 85 (1) ◽  
Author(s):  
Christoph Lemell ◽  
Konstantinos I. Dimitriou ◽  
Xiao-Min Tong ◽  
Stefan Nagele ◽  
Daniil V. Kartashov ◽  
...  
Keyword(s):  
Strong Field ◽  
Laser Pulses ◽  
Low Energy ◽  
Field Ionization ◽  
Two Dimensional ◽  
Atomic Potential ◽  
Strong Field Ionization ◽  
Peak Structure ◽  
Energy Peak

Static and Dynamic Properties of a Two-Dimensional Charged Bose Fluid

1998 ◽  
Vol 12 (12) ◽  
pp. 459-465 ◽  
Author(s):  
E. Strepparola ◽  
M. P. Tosi
Keyword(s):  
Coulomb Potential ◽  
Ground State ◽  
Coupling Strength ◽  
Dynamic Properties ◽  
Complete Solution ◽  
Mean Field ◽  
Strongly Correlated ◽  
Two Dimensional ◽  
Large Coupling ◽  
Field Approach

A complete solution of the Singwi–Tosi–Land–Sjölander approximation is given for the ground state and the elementary excitations of a fluid of charged bosons interacting via the two-dimensional ln (r) Coulomb potential at arbitrarily large coupling strength r s . The results are used to discuss the limitations of a static-mean-field approach in such a strongly correlated system.

Analysis of a mean field model of superconducting vortices

1999 ◽  
Vol 10 (4) ◽  
pp. 319-352 ◽  
Author(s):  
R. SCHÄTZLE ◽  
V. STYLES
Keyword(s):  
Weak Solution ◽  
Steady State ◽  
Free Boundary ◽  
Boundary Problem ◽  
Free Boundary Problem ◽  
Field Model ◽  
Mean Field ◽  
Two Dimensions ◽  
Mean Field Model ◽  
Superconducting Vortices

We study a mean-field model of superconducting vortices in one and two dimensions. The existence of a weak solution and a steady-state solution of the model are proved. A special case of the steady-state problem is shown to be of the form of a free boundary problem. The solutions of this free boundary problem are investigated. It is also shown that the weak solution of the one-dimensional model is unique and satisfies an entropy inequality.

PARITY VIOLATION AND SUPERCONDUCTIVITY IN DOPED MOTT INSULATORS

1990 ◽  
Vol 04 (04) ◽  
pp. 631-658 ◽  
Author(s):  
D. V. KHVESHCHENKO ◽  
YA. I. KOGAN
Keyword(s):  
Field Theory ◽  
Parity Violation ◽  
Ground State ◽  
Mean Field Theory ◽  
Mean Field ◽  
Electronic Systems ◽  
Strongly Correlated ◽  
Two Dimensional ◽  
Long Wavelength ◽  
Effective Lagrangian

We study parity violating states of strongly correlated two-dimensional electronic systems. On the basis of mean field theory for the SU (2N)-symmetric generalization of the system involved we give the arguments supporting the existence of these states at a filling number different from one-half. We derive an effective Lagrangian describing the long wavelength dynamics of magnetic excitations and their interaction with charged spinless holes. We establish that the ground state of a doped system is superconducting and discuss the phenomenological manifestations of the parity violation.

scholarly journals On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
A. N. Ribeiro ◽  
C. A. Macedo
Keyword(s):  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
Mean Field ◽  
Field Approximation ◽  
Square Lattice ◽  
Mean Field Approximation ◽  
Two Dimensional ◽  
Infinite Dimensions ◽  
Antiferromagnetic Correlations ◽  
Half Filling

The dynamical mean-field approximation (DMFA) becomes exact in the limit of infinite dimensions, and allows results to be obtained in a nonperturbative regime without the limitations normally found with exact diagonalization (ED) and quantum Monte Carlo (QMC) methods. In this paper, we investigate the applicability of the method to lattices with small coordination number in special situations. Specifically we use this approximation to study the two-dimensional (2D) Hubbard model on a square lattice far from half filling. In this situation, we calculate the specific heat and find that when the filling decreases, that is, antiferromagnetic correlations become less important, the agreement between DMFA and QMC results increases. Our results show that the DMFA can be a valuable technique for studying the thermodynamic properties of the Hubbard model also on a square lattice, but within a parameter range in which the antiferromagnetic correlations are not important.

KINETICS MODELS OF INELASTIC GASES

2002 ◽  
Vol 12 (07) ◽  
pp. 965-983 ◽  
Author(s):  
ANDREA BALDASSARRI ◽  
ANDREA PUGLISI ◽  
UMBERTO MARINI BETTOLO MARCONI
Keyword(s):  
Field Model ◽  
Mean Field ◽  
Lattice Models ◽  
Two Dimensions ◽  
Granular Gases ◽  
Mean Field Model ◽  
Structure Factors ◽  
Spatial Lattice ◽  
Maxwell Gas ◽  
Shed Light

In the present paper we review some recent progresses in the study of the dynamics of cooling granular gases, obtained using idealized models to address different issues of their kinetics. The inelastic Maxwell gas is studied as an introductory mean field model that has the major advantage of being exactly resoluble in the case of scalar velocities, showing an asymptotic velocity distribution with power law tails |v|-4. More realistic models can be obtained placing the same process on a spatial lattice. Two regimes are observed: an uncorrelated transient followed by a dynamical stage characterized by correlations in the velocity field in the form of shocks and vortices. The lattice models, in one and two dimensions, account for different numerical measurements: some of them agree with the already known results, while others have never been efficiently measured and shed light on the deviation from homogeneity. In particular in the velocity-correlated regime the computation of structure factors gives indication of a dynamics similar to that of a diffusion process on large scales with a more complex behavior at shorter scales.

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