32,107 research outputs found
Antiferromagnetic Order in Pauli Limited Unconventional Superconductors
We develop a theory of the coexistence of superconductivity (SC) and
antiferromagnetism (AFM) in CeCoIn5. We show that in Pauli-limited nodal
superconductors the nesting of the quasi-particle pockets induced by Zeeman
pair-breaking leads to incommensurate AFM with the moment normal to the field.
We compute the phase diagram and find a first order transition to the normal
state at low temperatures, absence of normal state AFM, and coexistence of SC
and AFM at high fields, in agreement with experiments. We also predict the
existence of a new double-Q magnetic phase
High efficiency dark-to-bright exciton conversion in carbon nanotubes
We report that dark excitons can have a large contribution to the emission
intensity in carbon nanotubes due to an efficient exciton conversion from a
dark state to a bright state. Time-resolved photoluminescence measurements are
used to investigate decay dynamics and diffusion properties of excitons, and we
obtain intrinsic lifetimes and diffusion lengths of bright excitons as well as
diffusion coefficients for both bright and dark excitons. We find that the
dark-to-bright transition rates can be considerably high, and that more than
half of the dark excitons can be transformed into the bright excitons. The
state transition rates have a large chirality dependence with a family pattern,
and the conversion efficiency is found to be significantly enhanced by adsorbed
air molecules on the surface of the nanotubes. Our findings show the nontrivial
significance of the dark excitons on the emission kinetics in low dimensional
materials, and demonstrate the potential for engineering the dark-to-bright
conversion process by using surface interactions.Comment: 7 pages, 4 figure
Single carbon nanotubes as ultrasmall all-optical memories
Performance improvements are expected from integration of photonic devices
into information processing systems, and in particular, all-optical memories
provide a key functionality. Scaling down the size of memory elements is
desirable for high-density integration, and the use of nanomaterials would
allow for devices that are significantly smaller than the operation
wavelengths. Here we report on all-optical memory based on individual carbon
nanotubes, where adsorbed molecules give rise to optical bistability. By
exciting at the high-energy tail of the excitonic absorption resonance,
nanotubes can be switched between the desorbed state and the adsorbed state. We
demonstrate reversible and reproducible operation of the nanotube optical
memory, and determine the rewriting speed by measuring the molecular adsorption
and desorption times. Our results underscore the impact of molecular-scale
effects on optical properties of nanomaterials, offering new design strategies
for photonic devices that are a few orders of magnitude smaller than the
optical diffraction limit.Comment: 8 pages, 6 figure
Latest Perspectives Concerning Renal Rehabilitation for Chronic Kidney Disease (CKD)
Renal rehabilitation for patients with chronic kidney disease (CKD) has been recently in focus. Its standard concept includes improved physical improvement of exercise tolerance, protein-energy wasting (PEW), and quality of life (QOL). International Society of Nephrology (ISN) conducted broad survey and presented a Global Kidney Health Atlas. Kidney Disease: Improving Global Outcomes (KDIGO) has conducted the nomenclature to describe CKD and the glossary in scientific publications. As for renal protective effect, some markers include unchanged/decreased creatinine or Cystatin C, reduction rate of urinary protein excretion (>20%), and reduction of estimated glomerular filtration rate (eGFR) or eGFRcys reduction rate (>30%)
Stark effect of excitons in individual air-suspended carbon nanotubes
We investigate electric-field induced redshifts of photoluminescence from
individual single-walled carbon nanotubes. The shifts scale quadratically with
field, while measurements with different excitation powers and energies show
that effects from heating and relaxation pathways are small. We attribute the
shifts to the Stark effect, and characterize nanotubes with different
chiralities. By taking into account exciton binding energies for air-suspended
tubes, we find that theoretical predictions are in quantitative agreement.Comment: 4 pages, 3 figure
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