The concept of heat has been known for a long time, and yet it is nontrivial to manipulate its flow. Here, we show that artificial materials can be engineered to guide the heat flow in unconventional ways. The conductivity of the artificial materials are engineered for diffusive energy transport of thermal conduction and experimentally shielding, concentrating, and inverting the applied heat flux.

The artificially engineered materials are otherwise known as metamaterials.

I will upload more details once the paper is published.

The acceptance notice is here.


Supradeep Narayana and Yuki Sato

Accepted Tuesday Jan 11, 2011

We report a new kind of experiment in which we take an array of nanoscale apertures that form a superfluid 4He Josephson junction and apply quantum phase gradients directly along the array. We observe collective coherent behaviors from aperture elements, leading to quantum interference. Connections to superconducting and BEC Josephson junctions as well as phase coherence among the superfluid aperture array are discussed.


Our paper has been accepted in PRL.  The link is here.  The abstract is below.

Direct observation of dynamical bifurcation in a superfluid Josephson junction

Supradeep Narayana and Yuki Sato

Accepted Tuesday Oct 19, 2010

We report a direct observation of dynamical bifurcation between two plasma oscillation states of a superfluid Josephson junction. We excite the superfluid plasma resonance into a nonlinear regime by driving below the natural plasma frequency and observe a clear transition between two dynamical states. We also demonstrate bifurcation by changing the potential well with temperature variations.

Off to work again……