skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Bond algebraic liquid phase in strongly correlated multiflavor cold atom systems

Abstract

When cold atoms are trapped in a square or cubic optical lattice, it should be possible to pump the atoms into excited p-level orbitals within each well. Following earlier work, we explore the metastable equilibrium that can be established before the atoms decay into the s-wave orbital ground state. We will discuss the situation with integer number of bosons on every site, and consider the strong correlation ''insulating'' regime. By employing a spin-wave analysis together with a duality transformation, we establish the existence and stability of a gapless ''critical phase,'' which we refer to as a ''bond algebraic liquid.'' The gapless nature of this phase is stabilized due to the emergence of symmetries which lead to a quasi-one-dimensional behavior. Within the algebraic liquid phase, both bond operators and particle flavor occupation number operators have correlations which decay algebraically in space and time. Upon varying parameters, the algebraic bond liquid can be unstable to either a Mott insulator phase which spontaneously breaks lattice symmetries, or a Z{sub 2} phase. The possibility of detecting the algebraic liquid phase in cold atom experiments is addressed. Although the momentum distribution function is insufficient to distinguish the algebraic bond liquid from other phases, the densitymore » correlation function can in principle be used to detect this phase of matter.« less

Authors:
 [1];  [2]
  1. Department of Physics, University of California, Berkeley, California 94720 (United States)
  2. Kavli Institute of Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)
Publication Date:
OSTI Identifier:
20957771
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 10; Other Information: DOI: 10.1103/PhysRevB.75.104428; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; BOSONS; CORRELATION FUNCTIONS; DECAY; DENSITY; DISTRIBUTION FUNCTIONS; ELECTRON CORRELATION; FLAVOR; GROUND STATES; LIQUIDS; METASTABLE STATES; OCCUPATION NUMBER; ONE-DIMENSIONAL CALCULATIONS; S WAVES; SPIN WAVES; SYMMETRY

Citation Formats

Xu, Cenke, and Fisher, Matthew P. A.. Bond algebraic liquid phase in strongly correlated multiflavor cold atom systems. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.104428.
Xu, Cenke, & Fisher, Matthew P. A.. Bond algebraic liquid phase in strongly correlated multiflavor cold atom systems. United States. doi:10.1103/PHYSREVB.75.104428.
Xu, Cenke, and Fisher, Matthew P. A.. Thu . "Bond algebraic liquid phase in strongly correlated multiflavor cold atom systems". United States. doi:10.1103/PHYSREVB.75.104428.
@article{osti_20957771,
title = {Bond algebraic liquid phase in strongly correlated multiflavor cold atom systems},
author = {Xu, Cenke and Fisher, Matthew P. A.},
abstractNote = {When cold atoms are trapped in a square or cubic optical lattice, it should be possible to pump the atoms into excited p-level orbitals within each well. Following earlier work, we explore the metastable equilibrium that can be established before the atoms decay into the s-wave orbital ground state. We will discuss the situation with integer number of bosons on every site, and consider the strong correlation ''insulating'' regime. By employing a spin-wave analysis together with a duality transformation, we establish the existence and stability of a gapless ''critical phase,'' which we refer to as a ''bond algebraic liquid.'' The gapless nature of this phase is stabilized due to the emergence of symmetries which lead to a quasi-one-dimensional behavior. Within the algebraic liquid phase, both bond operators and particle flavor occupation number operators have correlations which decay algebraically in space and time. Upon varying parameters, the algebraic bond liquid can be unstable to either a Mott insulator phase which spontaneously breaks lattice symmetries, or a Z{sub 2} phase. The possibility of detecting the algebraic liquid phase in cold atom experiments is addressed. Although the momentum distribution function is insufficient to distinguish the algebraic bond liquid from other phases, the density correlation function can in principle be used to detect this phase of matter.},
doi = {10.1103/PHYSREVB.75.104428},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 10,
volume = 75,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • We show that a new state of matter, the d-wave Mott-insulator state (d-Mott state) (introduced recently by [H. Yao, W. F. Tsai, and S. A. Kivelson, Phys. Rev. B 76, 161104 (2007)]), which is characterized by a nonzero expectation value of a local plaquette operator embedded in an insulating state, can be engineered using ultracold atomic fermions in two-dimensional double-well optical lattices. We characterize and analyze the parameter regime where the d-Mott state is stable. We predict the testable signatures of the state in the time-of-flight measurements.
  • Using exact diagonalization for a small system of cold bosonic atoms, we analyze the emergence of strongly correlated states in the presence of an artificial magnetic field. This gauge field is generated by a laser beam that couples two internal atomic states, and it is related to Berry's geometrical phase that emerges when an atom follows adiabatically one of the two eigenstates of the atom-laser coupling. Our approach allows us to go beyond the adiabatic approximation, and to characterize the generalized Laughlin wave functions that appear in the strong magnetic-field limit.
  • The influence of disorder and pseudogap fluctuations on the Mott insulator-metal transition in strongly correlated systems has been studied in the framework of the generalized dynamic mean field theory (DMFT + {Sigma} approach). Using the results of investigations of the density of states (DOS) and optical conductivity, a phase diagram (disorder-Hubbard interaction-temperature) is constructed for the paramagnetic Anderson-Hubbard model, which allows both the effects of strong electron correlations and the influence of strong disorder to be considered. Strong correlations are described using the DMFT, while a strong disorder is described using a generalized self-consistent theory of localization. The DOS andmore » optical conductivity of the paramagnetic Hubbard model have been studied in a pseudogap state caused by antiferromagnetic spin (or charge) short-range order fluctuations with a finite correlation length, which have been modeled by a static Gaussian random field. The effect of a pseudogap on the Mott insulator-metal transition has been studied. It is established that, in both cases, the static Gaussian random field (related to the disorder or pseudogap fluctuations) leads to suppression of the Mott transition, broadening of the coexistence region of the insulator and metal phases, and an increase in the critical temperature at which the coexistence region disappears.« less
  • Pseudogap formation is a ubiquitous phenomenon in strongly-correlated superconductors, for example cuprates, heavy-fermion superconductors, and iron pnictides. As the system is cooled, an energy gap opens in the excitation spectrum before entering the superconducting phase. The origin of formation and the relevancy to the superconductivity remain unclear, which is the most challenging problem in condensed matter physics. Here, using the cuprate as a model, we demonstrate that the formation of pseudogap is due to a massive gauge interaction between electrons, where the mass of the gauge boson, determining the interaction length scale, is the consequence of the remnant antiferromagnetic fluctuationmore » inherited from the parent compounds. Extracting from experimental data, we predict that there is a quantum phase transition belonging to the 2D XY universality class at the critical doping where pseudogap transition vanishes.« less
  • We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strongmore » correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing.« less