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Design and validation of world-class multilayered thermal emitter using machine learning

#artificialintelligence

NIMS, the University of Tokyo, Niigata University and RIKEN have jointly designed a multilayered metamaterial that realizes ultra-narrowband wavelength-selective thermal emission by combining the machine learning (Bayesian optimization) and thermal emission properties calculations (electromagnetic calculation). The joint team then experimentally fabricated the designed metamaterial and verified the performance. These results may facilitate the development of highly efficient energy devices. Thermal radiation, a phenomenon that an object emits heat as electromagnetic waves, is potentially applicable to a variety of energy devices, such as wavelength-selective heaters, infrared sensors and thermophotovoltaic generators. Highly efficient thermal emitters need to exhibit emission spectrum with narrow bands in practically usable wavelength range..


[Report] Quantized thermal transport in single-atom junctions

Science

Thermal transport in individual atomic junctions and chains is of great fundamental interest because of the distinctive quantum effects expected to arise in them. By using novel, custom-fabricated, picowatt-resolution calorimetric scanning probes, we measured the thermal conductance of gold and platinum metallic wires down to single-atom junctions. Our work reveals that the thermal conductance of gold single-atom junctions is quantized at room temperature and shows that the Wiedemann-Franz law relating thermal and electrical conductance is satisfied even in single-atom contacts. Furthermore, we quantitatively explain our experimental results within the Landauer framework for quantum thermal transport. The experimental techniques reported here will enable thermal transport studies in atomic and molecular chains, which will be key to investigating numerous fundamental issues that thus far have remained experimentally inaccessible.


Getting random with thermal noise

Science

Software-generated random numbers depend on an initial seed value, and thus a sequence can be replicated if one knows this initial seed. In contrast, one can generate true random numbers by tapping into random natural phenomena, such as noise caused by thermal fluctuations. Gaviria Rojas et al. built static random access memory (SRAM) cells from single-walled carbon nanotubes fixed onto polymer substrates. When the SRAM is first supplied with power, it exists in a metastable binary state. Whether it is on or off is then determined by thermal fluctuations.


How sensitive is the FLIR Lepton thermal camera built into the Blackview BV9800 Pro?

ZDNet

Once question I got a lot after posting about the Blackview BV9800 Pro was this -- how sensitive is the thermal camera? Another, more to the point question was -- is it useful or just a gimmick? Must read: Can a simple charging mistake cause your MacBook Pro to overheat? Rather than try to tell you how sensitive it is, I thought I'd show you by sharing a few different videos I captured. In testing, the camera seems pretty sensitive.


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Science

The act of position measurement alters the motion of an object being measured. This quantum measurement backaction is typically much smaller than the thermal motion of a room-temperature object and thus difficult to observe. By shining laser light through a nanomechanical beam, we measure the beam's thermally driven vibrations and perturb its motion with optical force fluctuations at a level dictated by the Heisenberg measurement-disturbance uncertainty relation. We demonstrate a cross-correlation technique to distinguish optically driven motion from thermally driven motion, observing this quantum backaction signature up to room temperature. We use the scale of the quantum correlations, which is determined by fundamental constants, to gauge the size of thermal motion, demonstrating a path toward absolute thermometry with quantum mechanically calibrated ticks.