1,436 research outputs found
Critical role of electronic correlations in determining crystal structure of transition metal compounds
The choice that a solid system "makes" when adopting a crystal structure
(stable or metastable) is ultimately governed by the interactions between
electrons forming chemical bonds. By analyzing 6 prototypical binary
transition-metal compounds we demonstrate here that the orbitally-selective
strong -electron correlations influence dramatically the behavior of the
energy as a function of the spatial arrangements of the atoms. Remarkably, we
find that the main qualitative features of this complex behavior can be traced
back to simple electrostatics, i.e., to the fact that the strong -electron
correlations influence substantially the charge transfer mechanism, which, in
turn, controls the electrostatic interactions. This result advances our
understanding of the influence of strong correlations on the crystal structure,
opens a new avenue for extending structure prediction methodologies to strongly
correlated materials, and paves the way for predicting and studying
metastability and polymorphism in these systems.Comment: Main text: 8 pages, 4 figures, 1 table; Supplemental material: 2
pages, 1 figure, 2 table
Studies on Rheological Behaviors of Bismaleimide Resin System for Resin Transfer Molding
AbstractThe rheological behavior of bismaleimide resin for resin transfer molding(RTM) was studied with DSC analysis and viscosity experiments. A rheological model based on the dual-Arrhenius equation was established and used to simulate the rheological behavior of the resin. The model predictions determined from the dual-Arrhenius equation were in good agreement with experimental data. The processing window of the resin system can be well determined based on the developed model. The rheological model is important for processing simulation and quality control of RTM processing for high performance composites
Emergent Bloch excitations in Mott matter
We develop a unified theoretical picture for excitations in Mott systems, portraying both the heavy quasiparticle excitations and the Hubbard bands as features of an emergent Fermi liquid state formed in an extended Hilbert space, which is nonperturbatively connected to the physical system. This observation sheds light on the fact that even the incoherent excitations in strongly correlated matter often display a well-defined Bloch character, with pronounced momentum dispersion. Furthermore, it indicates that the Mott point can be viewed as a topological transition, where the number of distinct dispersing bands displays a sudden change at the critical point. Our results, obtained from an appropriate variational principle, display also remarkable quantitative accuracy. This opens an exciting avenue for fast realistic modeling of strongly correlated materials
Rotationally invariant slave-boson and density matrix embedding theory: Unified framework and comparative study on the one-dimensional and two-dimensional Hubbard model
We present detailed benchmark ground-state calculations of the one- and two-dimensional Hubbard model utilizing the cluster extensions of the rotationally invariant slave-boson mean-field theory and the density matrix embedding theory. Our analysis shows that the overall accuracy and the performance of these two methods are very similar. Furthermore, we propose a unified computational framework that allows us to implement both of these techniques on the same footing. This provides us with a different line of interpretation and paves the ways for developing systematically distinct generalizations of these complementary approaches
Problem-tailored Simulation of Energy Transport on Noisy Quantum Computers
The transport of conserved quantities like spin and charge is fundamental to
characterizing the behavior of quantum many-body systems. Numerically
simulating such dynamics is generically challenging, which motivates the
consideration of quantum computing strategies. However, the relatively high
gate errors and limited coherence times of today's quantum computers pose their
own challenge, highlighting the need to be frugal with quantum resources. In
this work we report simulations on quantum hardware of infinite-temperature
energy transport in the mixed-field Ising chain, a paradigmatic many-body
system that can exhibit a range of transport behaviors at intermediate times.
We consider a chain with sites and find results broadly consistent with
those from ideal circuit simulators over 90 Trotter steps, containing up to 990
entangling gates. To obtain these results, we use two key problem-tailored
insights. First, we identify a convenient basis\unicode{x2013}the Pauli
basis\unicode{x2013}in which to sample the infinite-temperature trace and
provide theoretical and numerical justifications for its efficiency relative
to, e.g., the computational basis. Second, in addition to a variety of
problem-agnostic error mitigation strategies, we employ a renormalization
strategy that compensates for global nonconservation of energy due to device
noise. We expect that these techniques will prove useful beyond the specific
application considered here.Comment: 8 + 10 pages, 3 + 8 figure
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