We perform time- and angle-resolved photoemission spectroscopy (trARPES) on optimally doped Bi2Sr2CaCu2O8+δ (BSCCO-2212) using sufficient energy resolution (9 meV) to resolve the k -dependent ...near-nodal gap structure on time scales where the concept of an electronic pseudotemperature is a useful quantity, i.e., after electronic thermalization has occurred. We study the ultrafast evolution of this gap structure, uncovering a very rich landscape of decay rates as a function of angle, temperature, and energy. We explicitly focus on the quasiparticle states at the gap edge as well as on the spectral weight inside the gap that “fills” the gap—understood as an interaction, or self-energy effect—and we also make high resolution measurements of the nodal states, enabling a direct and accurate measurement of the electronic temperature (or pseudotemperature) of the electrons in the system. Rather than the standard method of interpreting these results using individual quasiparticle scattering rates that vary significantly as a function of angle, temperature, and energy, we show that the entire landscape of relaxations can be understood by modeling the system as following a nonequilibrium, electronic pseudotemperature that controls all electrons in the zone. Furthermore, this model has zero free parameters, as we obtain the crucial information of the SC gap Δ and the gap-filling strength ΓTDoS by connecting to static ARPES measurements. The quantitative and qualitative agreement between data and model suggests that the critical parameters and interactions of the system, including the pairing interactions, follow parametrically from the electronic pseudotemperature. We expect that this concept will be relevant for understanding the ultrafast response of a great variety of electronic materials, even though the electronic pseudotemperature may not be directly measurable.
Attention-deficit hyperactivity disorder (ADHD) is a heritable disorder, prevalent from childhood through adulthood. Although the noradrenergic (NA) system is thought to mediate a portion of the ...pathophysiology of ADHD, genes in this pathway have not been investigated as frequently as those in the dopaminergic system. Previous association studies of one candidate gene in the NA system, ADRA2A, showed inconsistent results with regard to an MspI polymorphism. In the current study, two nearby single-nucleotide polymorphisms, which define HhaI and DraI restriction fragment length polymorphisms, were also genotyped and were in significant linkage disequilibrium with the MspI RFLP. Transmission disequilibrium tests (TDTs) in a sample of 177 nuclear families showed significant association and linkage of the DraI polymorphism with the ADHD combined subtype (P=0.03), and the quantitative TDT showed association of this polymorphism with the inattentive (P=0.003) and hyperactive-impulsive (P=0.015) symptom dimensions. The haplotype that contained the less common allele of the DraI polymorphism likewise showed a strong relationship with the inattentive (P=0.001) and hyperactive-impulsive (P=0.004) symptom dimensions. This study supports the hypothesis that an allele of the ADRA2A gene is associated and linked with the ADHD combined subtype and suggests that the DraI polymorphism of ADRA2A is linked to a causative polymorphism.
Attention-deficit hyperactivity disorder (ADHD) is a heritable disorder, prevalent from childhood through adulthood. Although the noradrenergic (NA) system is thought to mediate a portion of the ...pathophysiology of ADHD, genes in this pathway have not been investigated as frequently as those in the dopaminergic system. Previous association studies of one candidate gene in the NA system, ADRA2A, showed inconsistent results with regard to an MspI polymorphism. In the current study, two nearby single-nucleotide polymorphisms, which define HhaI and DraI restriction fragment length polymorphisms, were also genotyped and were in significant linkage disequilibrium with the MspI RFLP. Transmission disequilibrium tests (TDTs) in a sample of 177 nuclear families showed significant association and linkage of the DraI polymorphism with the ADHD combined subtype (P=0.03), and the quantitative TDT showed association of this polymorphism with the inattentive (P=0.003) and hyperactive-impulsive (P=0.015) symptom dimensions. The haplotype that contained the less common allele of the DraI polymorphism likewise showed a strong relationship with the inattentive (P=0.001) and hyperactive-impulsive (P=0.004) symptom dimensions. This study supports the hypothesis that an allele of the ADRA2A gene is associated and linked with the ADHD combined subtype and suggests that the DraI polymorphism of ADRA2A is linked to a causative polymorphism.
Abstract
Layered nickelates have the potential for exotic physics similar to high
T
C
superconducting cuprates as they have similar crystal structures and these transition metals are neighbors in the ...periodic table. Here we present an angle-resolved photoemission spectroscopy (ARPES) study of the trilayer nickelate La
4
Ni
3
O
10
revealing its electronic structure and correlations, finding strong resemblances to the cuprates as well as a few key differences. We find a large hole Fermi surface that closely resembles the Fermi surface of optimally hole-doped cuprates, including its
$$d_{x^2-y^2}$$
d
x
2
-
y
2
orbital character, hole filling level, and strength of electronic correlations. However, in contrast to cuprates, La
4
Ni
3
O
10
has no pseudogap in the
$$d_{x^2-y^2}$$
d
x
2
-
y
2
band, while it has an extra band of principally
$$d_{3z^2-r^2}$$
d
3
z
2
-
r
2
orbital character, which presents a low temperature energy gap. These aspects drive the nickelate physics, with the differences from the cuprate electronic structure potentially shedding light on the origin of superconductivity in the cuprates.
We report the scalable fabrication and characterization of photonic crystal (PhC) nanobeam waveguides incorporating subwavelength-scale dielectric anti-slot unit cells. These anti-slot PhCs were ...fabricated using deep UV lithography on a monolithic silicon photonics technology. The dielectric band edge mode is characterized by strong field localization in the anti-slot region where the minimum dielectric feature size is approximately 70 nm. This demonstration opens the door to further investigation of subwavelength engineered photonic structures fabricated using commercial foundry processes for integrated photonics applications that benefit from enhanced light-matter interaction.
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