Spin current cross-correlations as a probe of magnon coherence

Motivated by the important role of the normalized second order coherence function, often called $g^{(2)}$, in the field of quantum optics, we propose a method to determine magnon coherence in solid-state devices. Namely, we show that the cross-correlations of pure spin-currents injected by a ferromagnet into two metal leads, normalized by their dc value, replicate the behavior of $g^{(2)}$ when magnons are driven far from equilibrium. We consider two scenarios: driving by ferromagnetic resonance, which leads to the coherent occupation of a single mode, and driving by heating of the magnons, which leads to an excess of incoherent magnons. We find an enhanced normalized cross-correlation in the latter case, thereby demonstrating bunching of nonequilibrium thermal magnons due to their bosonic statistics. Our results contribute to the burgeoning field of quantum magnonics, which seeks to explore and exploit the quantum nature of magnons

Magnon-Mediated Indirect Exciton Condensation through Antiferromagnetic Insulators

Electrons and holes residing on the opposing sides of an insulating barrier and experiencing an attractive Coulomb interaction can spontaneously form a coherent state known as an indirect exciton condensate. We study a trilayer system where the barrier is an antiferromagnetic insulator. The electrons and holes here additionally interact via interfacial coupling to the antiferromagnetic magnons. We show that by employing magnetically uncompensated interfaces, we can design the magnon-mediated interaction to be attractive or repulsive by varying the thickness of the antiferromagnetic insulator by a single atomic layer. We derive an analytical expression for the critical temperature $T_c$ of the indirect exciton condensation. Within our model, anisotropy is found to be crucial for achieving a finite $T_c$, which increases with the strength of the exchange interaction in the antiferromagnetic bulk. For realistic material parameters, we estimate $T_c$ to be around 7 K, the same order of magnitude as the current experimentally achievable exciton condensation where the attraction is solely due to the Coulomb interaction. The magnon-mediated interaction is expected to cooperate with the Coulomb interaction for condensation of indirect excitons, thereby providing a means to significantly increase the exciton condensation temperature range.Comment: 7+13 Pages, 2+1 figures. Added discussion of retardation effects. Accepted for publication in Phys. Rev. Let

Liposomes in dermatological diseases

Liposomes are vesicles comprising of spherical phospholipids making them useful for topical applications of drugs. Liposome research has been expanded considerably and nowadays, it is possible to construct a wide range of liposomes varying in size, phospholipids composition and surface characteristics. In dermatological diseases, the topical application of liposomes has proven to be of high therapeutic value. Liposomes can be used as carriers for hydrophilic as well as lipophilic therapeutic agents because of their amphipathic character. They may improve stabilization of instable drugs by encapsulating them. They have the potential to target drugs into the pilosebaceous structures and hence have an advantage for treatment of hair follicle-associated disorders. Liposomal encapsulated drugs are found useful in the treatment of acne, atopic dermatitis, psoriasis, vitiligo, superficial vein thrombosis and hair removal et

Curriculum Vitae (Feminae): Biography and Early American Women Lawyers

In this review, Carol Sanger examines the recent surge of interest in the lives of early women lawyers. Using Jane Friedman\u27s biography of Myra Bradwell, America\u27s First Woman Lawyer, as a starting point, Professor Sanger explores the complexities for the feminist biographer of reconciling for herself and for her subject conflicting professional, political, and personal sensibilities. Professor Sanger concludes that to advance the project of women\u27s history, feminist biographers ought not retreat to the comforts of commemorative Victorian biography, even for Victorian subject, but should instead strive to present and accept early women subjects on their own complex terms

An atmospheric electrical method to determine the eddy diffusion coefficient

The ion-aerosol balance equations are solved to get the profiles of atmospheric electric parameters over the ground surface in an aerosol-rich environment under the conditions of surface radioactivity. Combining the earlier results for low aerosol concentrations and the present results for high aerosol concentrations, a relation is obtained between the average value of atmospheric electric space charge in the lowest ~2 m, the surface electric field and eddy diffusivity/aerosol concentration. The values of eddy diffusivity estimated from this method using some earlier measurements of space charge and surface electric field are in reasonably good agreement with those calculated from other standard methods using meteorological or electrical variables

Complete TcT_c suppression and N\'eel triplets-mediated exchange in antiferromagnet-superconductor-antiferromagnet trilayers

An antiferromagnetic insulator (AFI) bearing a compensated interface to an adjacent conventional superconductor (S) has recently been predicted to generate N\'eel triplet Cooper pairs, whose amplitude alternates sign in space. Here, we theoretically demonstrate that such N\'eel triplets enable control of the superconducting critical temperature in an S layer via the angle between the N\'eel vectors of two enclosing AFI layers. This angle dependence changes sign with the number of S monolayers providing a distinct signature of the N\'eel triplets. Furthermore, we show that the latter mediate a similarly distinct exchange interaction between the two AFIs' N\'eel vectors.Comment: 7 pages, 4 figure

Changes in concentration and size distribution of aerosols during fog over the south Indian Ocean

Measurements of the concentration and size distribution of aerosol particles in the size-ranges of 0.5-20 μm and 16-700 nm diameters were made during six fog episodes over the south Indian Ocean. Observations show that concentrations of particles of all sizes start decreasing 1-2 hours before the occurrence of fog. This decrease is more prominent for coarse particles of >1 μm diameter and continues until 10-20 minutes before the onset of fog when particle concentrations in all size ranges rapidly increase by one/two orders of magnitude in ~20 minutes. Thereafter, concentrations of particles of all sizes gradually decrease until the dissipation of fog. After the fog dissipation, concentrations of coarse mode particles rapidly increase and restore to their pre-fog levels but concentrations of the Aitken mode particles decrease slowly and reach their pre-fog levels only after 1-2 hours. The net effect of fog is to change the bimodal size distributions of aerosols with a coarse mode at 1.0 μm and an accumulation mode at 40-60 nm to a power law size distribution. It is proposed that the preferential growth and sedimentation of the coarse mode hygroscopic particles in the initial phase cause a large decrease in the aerosol surface area. As a result, the low vapour pressure gases which were initially being used for the growth of coarse mode particles, now accelerate the growth rates of the accumulation and Aitken mode particles

Size-distribution of submicron aerosol particles over the Indian Ocean during IFP-99 of INDOEX

Measurements of the size-distribution of submicron aerosol particles of diameter from 0.003 to 1 μm are made over the Indian Ocean during the IFP-99 of the Indian Ocean Experiment (INDOEX). Measurements are made during the onward journey from Goa to Port Louis, Mauritius from 20 January to 11 February 1999 onboard ORV Sagar Kanya and during the return journey from Port Louis to Male from 22 February to 1 March 1999 onboard Ronald H. Brown. Observations show large concentrations in the range of 2-6 × 103 particles/cm3 over the Indian Ocean in the northern hemisphere and these drop down to about 500 particles/cm3 in the southern hemisphere. However, the aerosol concentrations show a peak of about 3 × 103 particles/cm3 at 13°S. In the northern hemisphere, the concentration of particles of diameter < 0.0749 μm increases from 14°N to 1°N and then steeply falls. On the other hand, the concentration of particles of diameter > 0.0749 μm keeps decreasing up to 6°S. Size distributions of particles at open sea in the northern hemisphere show a maximum at 0.133 μm and minimum at 0.0422 μm and are generally openended at the smaller size end. The size-distributions of particles are sometimes relatively flat from 0.0133 to 0.237 μm when the particle concentrations are low in the southern hemisphere. The transport and accumulation of aerosol particles in the Inter-Tropical Convergence Zone is discussed. The relative abundance of large versus small particles is examined with respect to the variation of surface atmospheric pressure along the route

Airborne measurements of submicron aerosols across the coastline at Bhubaneswar during ICARB

Airborne measurements of the number concentration and size distribution of aerosols from 13 to 700 nm diameter have been made at four vertical levels across a coastline at Bhubaneswar (20°25'N, 85°83'E) during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) programme conducted in March-April 2006. The measurements made during the constant-level flights at 0.5, 1, 2 and 3 km altitude levels extend ~100 km over land and ~150km over ocean. Aerosol number concentrations vary from 2200 to 4500 cm-3 at 0.5 km level but are almost constant at ~6000 cm-3 and ~800 cm-3 at 2 and 3 km levels, respectively. At 1km level, aerosol number concentration shows a peak of 18,070 cm-3 around the coastline. Most of the aerosol size distribution curves at 0.5 km and 1 km levels are monomodal with a maxima at 110 nm diameter which shifts to 70 nm diameter at 2 and 3 km levels. However, at the peak at 1 km level, number concentration has a bimodal distribution with an additional maximum appearing in nucleation mode. It is proposed that this maxima in nucleation mode at 1 km level may be due to the formation and transport of new particles from coastal regions