Heat radiation and transfer for nanoparticles in the presence of a cylinder

We study heat radiation and radiative heat transfer for nanoparticles in the presence of an infinitely long cylinder in different geometrical configurations, based on its electromagnetic Green's tensor. The heat radiation of a single particle can be enhanced by placing it close to a nanowire, and this enhancement can be much larger as compared to placing it close to a plate of the same material. The heat transfer along a cylinder decays much slower than through empty vacuum, being especially long-ranged in the case of a perfectly conducting nanowire, and showing nonmonotonic behavior in the case of a SiC cylinder. Exploring the dependence on the relative azimuthal angle of the nanoparticles, we find that the results are insensitive to small angles, but they can be drastically different when the angle is large, depending on the material. Finally, we demonstrate that a cylinder can either enhance or block the heat flux when placed perpendicular to the interparticle distance line, where the blocking in particular is strongly enhanced compared to the geometry of a sphere of same radius.