2,536 research outputs found
General Approach To Compute Phosphorescent OLED Efficiency
Phosphorescent organic light-emitting diodes (PhOLEDs) are widely used in the
display industry. In PhOLEDs, cyclometalated Ir(III) complexes are the most
widespread triplet emitter dopants to attain red, e.g., Ir(piq)3 (piq =
1-phenylisoquinoline), and green, e.g., Ir(ppy)3 (ppy = 2-phenylpyridine),
emissions, whereas obtaining operative deep-blue emitters is still one of the
major challenges. When designing new emitters, two main characteristics besides
colors should be targeted: high photostability and large photoluminescence
efficiencies. To date, these are very often optimized experimentally in a
trial-and-error manner. Instead, accurate predictive tools would be highly
desirable. In this contribution, we present a general approach for computing
the photoluminescence lifetimes and efficiencies of Ir(III) complexes by
considering all possible competing excited-state deactivation processes and
importantly explicitly including the strongly temperature-dependent ones. This
approach is based on the combination of state-of-the-art quantum chemical
calculations and excited-state decay rate formalism with kinetic modeling,
which is shown to be an efficient and reliable approach for a broad palette of
Ir(III) complexes, i.e., from yellow/orange to deep-blue emitters
Complexity of Sarcomere Protein Gene Mutations in Restrictive Cardiomyopathy
Restrictive cardiomyopathy (RCM) is characterized by impaired filling of the ventricles in the presence of normal wall thickness and systolic function. Although idiopathic RCM is rare compared to other types of cardiomyopathy, the effects are severe. Until recently, many sarcomere genes previously described to be causative mutations in hypertrophic cardiomyopathy and dilated cardiomyopathy have been reported in RCM. Nowadays, it is accepted that primary RCM is also within the spectrum of sarcomere disease. However, the relationship between the identified mutations in sarcomere genes and clinical manifestation are complex, and the possible pathogenic mechanisms are not fully understood. Besides, many RCM‐related sarcomere mutations were reported to cause variable clinical phenotype. Occasionally, “phenotype transition” may also be seen in an individual who was previously diagnosed with RCM
Many-body physics of spontaneously broken higher-rank symmetry: from fractonic superfluids to dipolar Hubbard model
Fractonic superfluids are exotic phases of matter in which bosons are subject
to mobility constraints, resulting in features beyond those of conventional
superfluids. These exotic phases arise from the spontaneous breaking of
higher-rank symmetry (HRS) in many-body systems with higher-moment
conservation, such as dipoles, quadrupoles, and angular moments. The aim of
this paper is to introduce exciting developments on the theory of spontaneous
symmetry breaking in such systems, which we refer to as ``many-fracton
systems''. More specifically, we introduce exciting progress on general aspects
of HRS, minimal model construction, realization of symmetry-breaking ground
states, order parameter, off-diagonal long-range order (ODLRO), Noether
currents with continuity equations, Gross-Pitaevskii equations, quantum
fluctuations, Goldstone modes, specific heat, generalized Mermin-Wagner
theorem, critical current, Landau criterion, symmetry defects, and
Kosterlitz-Thouless (KT)-like physics, hydrodynamics, and dipolar Hubbard model
realization. This paper is concluded with several future directions.Comment: Title changed, references updated. A short review on recent progress
on higher rank symmetry breaking, fractonic superfluids, dipole (and other
higher moments) conservation, and related topic
Anisotropic Rabi model
We define the anisotropic Rabi model as the generalization of the spin-boson
Rabi model: The Hamiltonian system breaks the parity symmetry; the rotating and
counter-rotating interactions are governed by two different coupling constants;
a further parameter introduces a phase factor in the counter-rotating terms.
The exact energy spectrum and eigenstates of the generalized model is worked
out. The solution is obtained as an elaboration of a recent proposed method for
the isotropic limit of the model. In this way, we provide a long sought
solution of a cascade of models with immediate relevance in different physical
fields, including i) quantum optics: two-level atom in single mode cross
electric and magnetic fields; ii) solid state physics: electrons in
semiconductors with Rashba and Dresselhaus spin-orbit coupling; iii) mesoscopic
physics: Josephson junctions flux-qubit quantum circuits.Comment: 5 pages+ 6 pages supplementary, 7 figures, accepted by Phys. Rev.
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