Objects at finite temperature emit thermal radiation with an outward energy-momentum flow, which exerts pressure. At room temperature, a cesium atom scatters on average less than one of these blackbody photons every 10^8 years. Thus, it is generally assumed that any scattering force exerted atoms by such negligible. However, also interact coherently the electromagnetic field. In this work, we measure attractive induced between and heated, centimeter-sized cylinder orders magnitude stronger...

Flexible power provision from biogas can significantly contribute to energy systems with high shares of renewables. However, the characteristics and demands for this flexibility are not clearly defined or measured. In paper eight indicators shape "flexibility" perform a downstream investigation research projects focusing on flexible plants. The structured in three dimensions (1) velocity (ramps) by which system be modulated, (2) range (bandwidth) (3) duration specific load conditions. Based...

The usual multipolar Hamiltonian for atom-light interaction features a non-relativistic moving atom interacting with electromagnetic fields which inherently follow Lorentzian symmetry. This combination can lead to situations where atoms appear experience friction force, when in fact they only change their internal mass-energy due the emission or absorption of photon. Unfortunately simple Galilean description atom's motion is not sufficient distinguish between momentum acceleration and...

We show how a simple calculation leads to the surprising result that an excited two-level atom moving through vacuum sees tiny friction force of first order in v/c. At sight this seems be obvious contradiction other calculations showing interaction with does not change velocity atom. It is even more atom's momentum turns out necessary energy and conservation special relativity.

Abstract The current state of the art in mixing biogas digesters is described and areas where future research needs to be concentrated are outlined. Since biggest contributor energy consumption digesters, it important optimize order improve overall cost‐effectiveness biodigestion. This optimization problem a large‐scale nonlinear mixed‐integer with many decision variables. Also, an artificial substrate for lab‐scale experimental studies on digester introduced. has several properties crucial...

Abstract To keep biogas production competitive against alternatives in the energy sector, operating costs of plants must be reduced. Up to 50 % consumption is contributed by mixing biomass slurry. Thus, optimization system a promising approach increase overall efficiency plants. Investigations find optimal conditions are challenging full‐scale digesters. Two main strategies study laboratories build scale‐down digester using an artificial substrate mimic biomass, and develop computational...

Blackbody radiation around hot objects induces ac Stark shifts of the energy levels nearby atoms and molecules. These are roughly proportional to fourth power temperature induce a force decaying with third distance from object. We explicitly calculate resulting attractive blackbody optical dipole for ground state hydrogen atoms. Surprisingly, this can surpass repulsive pressure actually pull against flow towards surface stronger than gravity. exemplify dominance ``blackbody force'' over...

Abstract We report an algorithm for reconstructing images when the average number of photons recorded per pixel is order unity, i.e. photon-sparse data. The image optimisation minimises a cost function incorporating both Poissonian log-likelihood term based on deviation reconstructed from measured data and regularization-term upon sum moduli second spatial derivatives intensities. balance between these two terms set by bootstrapping technique where target value deduced smoothed version...

Investigating dynamic viscosity of aqueous cellulose solutions to mimic biomass slurry in scale-down laboratory tanks representing biogas digesters.

Imaging technologies working at very low light levels acquire data by counting the number of photons impinging on each pixel.Especially in cases with, average, less than one photocount per pixel, resulting images are heavily corrupted Poissonian noise.To tackle this problem, we use methods from Bayesian statistics to retrodict spatial intensity distribution responsible for measurements.Unlike usual photon-limited image denoising algorithms, calculate full probability distributions...

Collective coherent scattering of laser light by an ensemble polarizable point particles creates long-range interactions, whose properties can be tailored the choice injected powers, frequencies, and polarizations. We use a transfer matrix approach to study forces induced non-interfering fields orthogonal polarization or different frequencies in 1D geometry, find self-ordering without prescribed order. Adjusting powers allows one tune inter-particle distances provides wide range possible...

Light forces induced by scattering and absorption in elastic dielectrics lead to local density modulations deformations. These perturbations turn modify light propagation the medium generate an intricate nonlinear response. We generalize analytic approach where one-dimensional media of inhomogeneous is modelled as a result multiple between polarizable slices. Using Maxwell stress tensor formalism we compute optical iteratively self-consistent distributions back-action balances gradient-...

We know that in empty space there is no preferred state of rest. This true both special relativity but also Newtonian mechanics with its associated Galilean relativity. It comes as something a surprise, therefore, to discover the existence friction force spontaneous emission. he resolution this paradox relies on central idea from even though our derivation it non-relativistic. examine possibility physics underlying effect might be explored an ion trap, via observation superposition different...

Abstract With the expansion of renewable, but fluctuating power generation from wind and solar energy, demand placed on security reliability supply is increasing. To ensure grid stability in future, controllable production via biogas plants has great technical economic potential. In order to demonstrate operation electricity production, an existing industrial‐scale plant was modified produce accordance demands market. course scientific monitoring, extensive instrumentation installed at...

The Röntgen term is an often neglected contribution to the interaction between atom and electromagnetic field in electric dipole approximation. In this work we discuss how leads a difference kinetic canonical momentum of which, turn, surprising radiation forces acting on atom. We use number examples explore main features interaction, namely against expected force or accelerations perpendicular beam propagation axis.

Light-matter interaction is well understood on the single-atom level and routinely used to manipulate atomic gases. However, in denser ensembles, collective effects emerge that are caused by light-induced dipole-dipole interactions multiple photon scattering. Here, we report observation of a mechanical deformation cloud ultracold Rb87 atoms due interplay homogenous light field. This scattering results self-confining potential with interesting features: It exhibits nonlocal properties,...

We show that the optical properties of an extended dielectric object are reliably reproduced by a large number thin slices forming linear array beam splitters. In infinite slice limit this self-consistent approach allows to calculate light forces within medium directly from Maxwell stress tensor for any with prescribed refractive index distribution. For generic example thick slab in counterpropagating fields effective force and internal strain distribution strongly depend on object's...

Abstract An increasing share of fluctuating energy generation leads to new challenges in power grids. In addition, the demand for flexible plants is growing. Solid biomass‐fueled combined heat and (CHP) are able get modified into dispatchable plants. Boundaries this operation mode summarized several measures achieve a biomass CHP concluded. The integration high‐temperature storage system buffering plants' steam seems be most promising, however, least investigated option. tasks necessary...

We employ quantum retrodiction to develop a robust Bayesian algorithm for reconstructing the intensity values of an image from sparse photocount data, while also accounting detector noise in form dark counts. This method yields not only reconstructed but provides full probability distribution function at each pixel. use simulated as well real data illustrate both applications and analysis options that are available when functions known. These include calculating credible regions pixel...

The frequency of light emitted by a moving source is shifted factor proportional to its velocity. We find that this Doppler shift requires the existence paradoxical effect: atom radiating in otherwise empty space feels net or average force acing against direction motion and magnitude speed. Yet there no preferred rest frame, either relativity Newtonian mechanics, so how can be vacuum friction force?

Black--body radiation around hot objects creates AC~Stark shifts in nearby atoms proportional to the fourth power of temperature inducing an attractive dipole force. For hydrogen it can be stronger than gravity and surpass repulsive pressure.

Imaging technologies working at very low light levels acquire data by attempting to count the number of photons impinging on each pixel. Especially in cases with, average, less than one photocount per pixel resulting images are heavily corrupted Poissonian noise and a host successful algorithms trying reconstruct original image from this noisy have been developed. Here we review recently proposed scheme that complements these calculating full probability distribution for local intensity...