Dissociation scattering length of ground state trimers

Eksperimentalne i teorijske procjene disocijacijske duljine raspršenja trimera $a_-$ u odnosu na van der Waalsovu duljinu $R_6$ pojavljuju se unutar raspona $2a_-$ = $9R_6 ± 20$% zbog čega se kategoriziraju kao univerzalne. U pokušaju da umanjimo devijaciju univerzalnosti duljine raspršenja atomskog trimera u osnovnom stanju proveli smo simulacije koristeći kvantne Monte Carlo metode s naglaskom na difuzijski Monte Carlo, koji, do na statističku pogrešku, egzaktno rješava Schrödingerovu jednadžbu u imaginarnom vremenu. Ispitani su razni modeli Lennard-Jones potencijala karakterističnih za interakcije neutralnih atoma, odnosno čiji se dugo dosežni utjecaj opisuje s $-C_6r^{−6}$. Svi su rezultati dobiveni unutar spomenutog raspona, a konačne analize rezultirale su procjenom $2a_-$ = $−9.58R_6 ± 1.6$% čija je devijacija puno manja od gore spomenutoga raspona. Dobiveni rezultati upućuju da bi odnos mogao biti univerzalan, ali ne možemo sa sigurnošću tvrditi dok se analizom više različitih sustava ne utvrdi postoji li dodatni parametar koji narušava idealan univerzalni odnos i uzrokuje blagu raspršenost istoga.Experimental and theoretical estimates for dissociation scattering length of atomic trimers $a_-$ in regards to van der Waals length $R_6$ produce results within $2a_-$ = $9R_6 ± 20$% which deems them as universal. In an attempt to reduce the deviation in the universality of scattering length of ground state atomic trimers we conducted simulations based on Quantum Monte Carlo methods, with an emphasis on Diffusion Monte Carlo, which exactly solves Schrödinger’s equation in imaginary time, with a statistical margin of error. Various models of Lennard-Jones interaction potentials between neutral atoms are tested, meaning those whose long-range effect can be described as $-C_6r^{−6}$. All results fall within the aforementioned range, while final analysis resulted in an estimate of $2a_-$ = $−9.58R_6 ± 1.6$%; a much lesser deviation than the aforementioned. Results indicate that the relation might be universal, however, we can not make that claim until additional systems are analysed and the existence of an additional parameter, which could potentially downgrade the ideal universal relation and cause a mild spread

Rainbow

Duga je kompleksna svjetlosna pojava koja za potpun opis zahtjeva primjenu i geometrijske i valne optike. U ovom radu obrađeni su samo efekti koji se mogu tumačiti geometrijskom optikom. To su kutovi pod kojim se vidi duga određenog reda, redoslijed boja po visini, te veći intenzitet svjetlosti pri dnu nego pri vrhu duge. Ako dugu promatramo kao liniju koje dijeli nebo na prostor unutar i izvan nje protumačena je skokovita promjena intenziteta svjetlosti pri prijelazu preko nje.Rainbows are complex light-based phenomena, the description of which requires both geometrical and wave optics. This paper revolves around the features that can be described using geometrical optics only. These features are: the angle at which rainbows are visible, the order of colours and the increase of light intensity at the bottom, as opposed to the top of the rainbow. If we are to consider the rainbow to be a curve separating the sky into a „inside“ and „outside“ regions, we can also successfully explain the difference of light intensity which occurs when crossing from one region into another

Dissociation scattering length of ground state trimers

Eksperimentalne i teorijske procjene disocijacijske duljine raspršenja trimera $a_-$ u odnosu na van der Waalsovu duljinu $R_6$ pojavljuju se unutar raspona $2a_-$ = $9R_6 ± 20$% zbog čega se kategoriziraju kao univerzalne. U pokušaju da umanjimo devijaciju univerzalnosti duljine raspršenja atomskog trimera u osnovnom stanju proveli smo simulacije koristeći kvantne Monte Carlo metode s naglaskom na difuzijski Monte Carlo, koji, do na statističku pogrešku, egzaktno rješava Schrödingerovu jednadžbu u imaginarnom vremenu. Ispitani su razni modeli Lennard-Jones potencijala karakterističnih za interakcije neutralnih atoma, odnosno čiji se dugo dosežni utjecaj opisuje s $-C_6r^{−6}$. Svi su rezultati dobiveni unutar spomenutog raspona, a konačne analize rezultirale su procjenom $2a_-$ = $−9.58R_6 ± 1.6$% čija je devijacija puno manja od gore spomenutoga raspona. Dobiveni rezultati upućuju da bi odnos mogao biti univerzalan, ali ne možemo sa sigurnošću tvrditi dok se analizom više različitih sustava ne utvrdi postoji li dodatni parametar koji narušava idealan univerzalni odnos i uzrokuje blagu raspršenost istoga.Experimental and theoretical estimates for dissociation scattering length of atomic trimers $a_-$ in regards to van der Waals length $R_6$ produce results within $2a_-$ = $9R_6 ± 20$% which deems them as universal. In an attempt to reduce the deviation in the universality of scattering length of ground state atomic trimers we conducted simulations based on Quantum Monte Carlo methods, with an emphasis on Diffusion Monte Carlo, which exactly solves Schrödinger’s equation in imaginary time, with a statistical margin of error. Various models of Lennard-Jones interaction potentials between neutral atoms are tested, meaning those whose long-range effect can be described as $-C_6r^{−6}$. All results fall within the aforementioned range, while final analysis resulted in an estimate of $2a_-$ = $−9.58R_6 ± 1.6$%; a much lesser deviation than the aforementioned. Results indicate that the relation might be universal, however, we can not make that claim until additional systems are analysed and the existence of an additional parameter, which could potentially downgrade the ideal universal relation and cause a mild spread

Rainbow

Duga je kompleksna svjetlosna pojava koja za potpun opis zahtjeva primjenu i geometrijske i valne optike. U ovom radu obrađeni su samo efekti koji se mogu tumačiti geometrijskom optikom. To su kutovi pod kojim se vidi duga određenog reda, redoslijed boja po visini, te veći intenzitet svjetlosti pri dnu nego pri vrhu duge. Ako dugu promatramo kao liniju koje dijeli nebo na prostor unutar i izvan nje protumačena je skokovita promjena intenziteta svjetlosti pri prijelazu preko nje.Rainbows are complex light-based phenomena, the description of which requires both geometrical and wave optics. This paper revolves around the features that can be described using geometrical optics only. These features are: the angle at which rainbows are visible, the order of colours and the increase of light intensity at the bottom, as opposed to the top of the rainbow. If we are to consider the rainbow to be a curve separating the sky into a „inside“ and „outside“ regions, we can also successfully explain the difference of light intensity which occurs when crossing from one region into another

Dissociation scattering length of ground state trimers

Eksperimentalne i teorijske procjene disocijacijske duljine raspršenja trimera $a_-$ u odnosu na van der Waalsovu duljinu $R_6$ pojavljuju se unutar raspona $2a_-$ = $9R_6 ± 20$% zbog čega se kategoriziraju kao univerzalne. U pokušaju da umanjimo devijaciju univerzalnosti duljine raspršenja atomskog trimera u osnovnom stanju proveli smo simulacije koristeći kvantne Monte Carlo metode s naglaskom na difuzijski Monte Carlo, koji, do na statističku pogrešku, egzaktno rješava Schrödingerovu jednadžbu u imaginarnom vremenu. Ispitani su razni modeli Lennard-Jones potencijala karakterističnih za interakcije neutralnih atoma, odnosno čiji se dugo dosežni utjecaj opisuje s $-C_6r^{−6}$. Svi su rezultati dobiveni unutar spomenutog raspona, a konačne analize rezultirale su procjenom $2a_-$ = $−9.58R_6 ± 1.6$% čija je devijacija puno manja od gore spomenutoga raspona. Dobiveni rezultati upućuju da bi odnos mogao biti univerzalan, ali ne možemo sa sigurnošću tvrditi dok se analizom više različitih sustava ne utvrdi postoji li dodatni parametar koji narušava idealan univerzalni odnos i uzrokuje blagu raspršenost istoga.Experimental and theoretical estimates for dissociation scattering length of atomic trimers $a_-$ in regards to van der Waals length $R_6$ produce results within $2a_-$ = $9R_6 ± 20$% which deems them as universal. In an attempt to reduce the deviation in the universality of scattering length of ground state atomic trimers we conducted simulations based on Quantum Monte Carlo methods, with an emphasis on Diffusion Monte Carlo, which exactly solves Schrödinger’s equation in imaginary time, with a statistical margin of error. Various models of Lennard-Jones interaction potentials between neutral atoms are tested, meaning those whose long-range effect can be described as $-C_6r^{−6}$. All results fall within the aforementioned range, while final analysis resulted in an estimate of $2a_-$ = $−9.58R_6 ± 1.6$%; a much lesser deviation than the aforementioned. Results indicate that the relation might be universal, however, we can not make that claim until additional systems are analysed and the existence of an additional parameter, which could potentially downgrade the ideal universal relation and cause a mild spread

Reconstruction Methods in Oceanographic Satellite Data Observation—A Survey

Oceanographic parameters, such as sea surface temperature, surface chlorophyll-a concentration, sea surface ice concentration, sea surface height, etc., are listed as Essential Climate Variables. Therefore, there is a crucial need for persistent and accurate measurements on a global scale. While in situ methods tend to be accurate and continuous, these qualities are difficult to scale spatially, leaving a significant portion of Earth’s oceans and seas unmonitored. To tackle this, various remote sensing techniques have been developed. One of the more prominent ways to measure the aforementioned parameters is via satellite spacecraft-mounted remote sensors. This way, spatial coverage is considerably increased while retaining significant accuracy and resolution. Unfortunately, due to the nature of electromagnetic signals, the atmosphere itself and its content (such as clouds, rain, etc.) frequently obstruct the signals, preventing the satellite-mounted sensors from measuring, resulting in gaps—missing data—in satellite recordings. One way to deal with these gaps is via various reconstruction methods developed through the past two decades. However, there seems to be a lack of review papers on reconstruction methods for satellite-derived oceanographic variables. To rectify the lack, this paper surveyed more than 130 articles dealing with the issue of data reconstruction. Articles were chosen according to two criteria: (a) the article has to feature satellite-derived oceanographic data (b) gaps in satellite data have to be reconstructed. As an additional result of the survey, a novel categorising system based on the type of input data and the usage of time series in reconstruction efforts is proposed

CCGAN as a Tool for Satellite-Derived Chlorophyll <i>a</i> Concentration Gap Reconstruction

This work represents a modification of the Context Conditional Generative Adversarial Network as a novel implementation of a non-linear gap reconstruction approach of missing satellite-derived chlorophyll a concentration data. By adjusting the loss functions of the network to focus on the structural credibility of the reconstruction, high numerical and structural reconstruction accuracies have been achieved in comparison to the original network architecture. The network also draws information from proxy data, sea surface temperature, and bathymetry, in this case, to improve the reconstruction quality. The implementation of this novel concept has been tested on the Adriatic Sea. The most accurate model reports an average error of 0.06mgm−3 and a relative error of 3.87%. A non-deterministic method for the gap-free training dataset creation is also devised, further expanding the possibility of combining other various oceanographic data to possibly improve the reconstruction efforts. This method, the first of its kind, has satisfied the accuracy requirements set by scientific communities and standards, thus proving its validity in the initial stages of conceptual utilisation

Observation of Abrupt Changes in the Sea Surface Layer of the Adriatic Sea

We observed interannual changes in the temperature and salinity of the surface layer of the Adriatic Sea when measured during the period 2005&ndash;2020. We observed non-stationarity and a positive linear trend in the series of mixed layer depth, heat storage, and potential energy anomalies. This non-stationarity was related to the climate regime that prevailed between 2011 and 2017. We observed significant changes in the interannual variability of salinity above and below the mixed layer depth and a positive difference in the surface barrier layer. In an effort to reconstruct the cause of this phenomenon, a multi-stage investigation was conducted. The first suspected culprit was the change in wind regime over the Mediterranean and Northeast Atlantic regions in September. Using the growing neural gas algorithm, September wind fields over the past 40 years were classified into nine distinct patterns. Further analysis of the CTD data indicated an increase in heat storage, a physical property of the Adriatic Sea known to be strongly influenced by the inflow of warm water masses controlled by the bimodal oscillating system (BiOS). The observed increase in salinity confirmed the assumption that BiOS activity affects heat storage. Unexpectedly, this analysis showed that an inverse vertical salinity profile was present during the summer months of 2015, 2017, and 2020, which can only be explained by salinity changes being a dominant factor. In addition, the aforementioned wind regime caused an increase in energy loss through latent energy dissipation, contributing to an even larger increase in salinity. While changes in the depth of the mixed layer in the Adriatic are usually due to temperature changes, this phenomenon was primarily caused by abrupt changes in salinity due to a combination of BiOS and local factors. This is the first record of such an event

Observation of Abrupt Changes in the Sea Surface Layer of the Adriatic Sea

We observed interannual changes in the temperature and salinity of the surface layer of the Adriatic Sea when measured during the period 2005–2020. We observed non-stationarity and a positive linear trend in the series of mixed layer depth, heat storage, and potential energy anomalies. This non-stationarity was related to the climate regime that prevailed between 2011 and 2017. We observed significant changes in the interannual variability of salinity above and below the mixed layer depth and a positive difference in the surface barrier layer. In an effort to reconstruct the cause of this phenomenon, a multi-stage investigation was conducted. The first suspected culprit was the change in wind regime over the Mediterranean and Northeast Atlantic regions in September. Using the growing neural gas algorithm, September wind fields over the past 40 years were classified into nine distinct patterns. Further analysis of the CTD data indicated an increase in heat storage, a physical property of the Adriatic Sea known to be strongly influenced by the inflow of warm water masses controlled by the bimodal oscillating system (BiOS). The observed increase in salinity confirmed the assumption that BiOS activity affects heat storage. Unexpectedly, this analysis showed that an inverse vertical salinity profile was present during the summer months of 2015, 2017, and 2020, which can only be explained by salinity changes being a dominant factor. In addition, the aforementioned wind regime caused an increase in energy loss through latent energy dissipation, contributing to an even larger increase in salinity. While changes in the depth of the mixed layer in the Adriatic are usually due to temperature changes, this phenomenon was primarily caused by abrupt changes in salinity due to a combination of BiOS and local factors. This is the first record of such an event