On Wheeler's delayed-choice Gedankenexperiment and its laboratory realization

Here, we present an analysis and interpretation of the experiment performed by Jacques et al. (2007 Science 315, 966), which represents a realization of Wheeler's delayed-choice Gedankenexperiment. Our analysis is based on the evolution of the photon state, since the photon enters into the Mach-Zehnder interferometer with a removable beam-splitter until it exits. Given the same incident photon state onto the output beam-splitter, BS_output, the photon's state at the exit will be very different depending on whether BS_output is on or off. Hence, the statistics of photon counts collected by the two detectors, positioned along orthogonal directions at the exit of the interferometer, is also going to be very different in either case. Therefore, it is not that the choice of inserting (on) or removing (off) a beam-splitter leads to a delayed influence on the photon behavior before arriving at the beam-splitter, but that such a choice influences the photon state at and after BS_output, i.e., after it has exited from the Mach-Zehnder interferometer. The random on/off choice at BS_output has no delayed effect on the photon to behave as a wave or a corpuscle at the entrance and inside the interferometer, but influences the subsequent evolution of the photon state incident onto BS_output.Comment: 7 pages, 4 figure

Fine Structure in Energy Spectra of Ultrasmall Au Nanoparticles

We have studied tunneling into individual Au nanoparticles of estimated diameters 2-5 nm, at dilution refrigerator temperatures. The I-V curves indicate resonant tunneling via discrete energy levels of the particle. Unlike previously studied normal metal particles of Au and Al, in these samples we find that the lowest energy tunneling resonances are split into clusters of 2-10 subresonances. Such effects appear to be increasingly important in smaller grains, as might be expected from the larger characteristic energies.Comment: 1 pdf fil

Modelling Electron Spin Accumulation in a Metallic Nanoparticle

A model describing spin-polarized current via discrete energy levels of a metallic nanoparticle, which has strongly asymmetric tunnel contacts to two ferromagnetic leads, is presented. In absence of spin-relaxation, the model leads to a spin-accumulation in the nanoparticle, a difference ($\Delta\mu$) between the chemical potentials of spin-up and spin-down electrons, proportional to the current and the Julliere's tunnel magnetoresistance. Taking into account an energy dependent spin-relaxation rate $\Omega (\omega)$, $\Delta\mu$ as a function of bias voltage ($V$) exhibits a crossover from linear to a much weaker dependence, when $|e|\Omega (\Delta\mu)$ equals the spin-polarized current through the nanoparticle. Assuming that the spin-relaxation takes place via electron-phonon emission and Elliot-Yafet mechanism, the model leads to a crossover from linear to $V^{1/5}$ dependence. The crossover explains recent measurements of the saturation of the spin-polarized current with $V$ in Aluminum nanoparticles, and leads to the spin-relaxation rate of $\approx 1.6 MHz$ in an Aluminum nanoparticle of diameter $6nm$, for a transition with an energy difference of one level spacing.Comment: 37 pages, 7 figure

Coherence loss and revivals in atomic interferometry: A quantum-recoil analysis

The coherence effects induced by external photons coupled to matter waves inside a MachZehnder three-grating interferometer are analyzed. Alternatively to atomphoton entanglement scenarios, the model considered here only relies on the atomic wavefunction and the momentum shift induced in it by the photon scattering events. A functional dependence is thus found between the observables, namely the fringe visibility and the phase shift, and the transversal momentum transfer distribution. Good quantitative agreement is found when comparing the results obtained from our model with the experimental data. © 2012 IOP Publishing Ltd.MD, MB and DA acknowledge support from the Ministry of Science of Serbia under Projects OI171005, OI171028 and III45016. ASS acknowledges support from the Ministerio de Econom´ıa y Competitividad (Spain) under Projects FIS2010-22082 and FIS2010-29596-C02-01, as well as for a “Ram´on y Cajal” Research Fellowship.Peer Reviewe

Analiza prikaza digitalnih modela terena primjenom različitih metoda interpolacije

In the paper is described the process of creating digital terrain models (DTM) using different interpolation methods. The analyses show the accuracy of the DTM obtained from topographic maps at different scales and using different interpolation methods. The quality and accuracy of DTM depends on the complexity of the terrain, data sources, and methods of height interpolation. The basic idea is the creation of the DTM for the selected area and the comparison of the results by applying appropriate interpolation methods. The aim of the research is to analyse the quality of the DTM model and to consider suitability of certain interpolation methods, based on the obtained results, i.e. their advantages and disadvantages. The experiment was done in the software environment ERDAS IMAGINE 2014.Rad opisuje postupak izrade digitalnih modela terena (DMT) primjenom različitih metoda interpolacije. Pritom se analiziraju prikaz i točnost DMT-a, dobiveni s topografskih karata različitih mjerila te primjenom različitih metoda interpolacije. Kvaliteta i točnost DMT-a ovise o složenosti reljefa, izvoru podataka, ali i o metodi interpolacije visina. Osnovna ideja u radu je kreiranje DMT-a za izabrano područje te primjenom odgovarajućih metoda interpolacije usporediti dobivene rezultate. Cilj istraživanja je analizirati kvalitetu DMT-a te na temelju dobivenih rezultata razmotriti pogodnost pojedinih metoda interpolacije, odnosno njihove prednosti i mane. Istraživanje je realizirano u softverskom okruženju ERDAS IMAGINE 2014

Properties of the quantum state arising after the L-photon state has passed trough a linear quantum amplifier

We consider the system of N two-level atoms, of which N0 atoms are unexcited and N1 are excited. This system of N two-level atoms, which forms a linear quantum amplifier, interacts with a single-mode electromagnetic field. The problem of amplification of the L-photon states using such an amplifier is studied. The evolution of the electromagnetic field density matrix is described by the master equation for the field under amplification. The dynamics of this process is such that it can be described as the transformation of the scale of the phase space. The exact solution of the master equation is expressed using the transformed Husimi function of the L-quantum state of the harmonic oscillator. The properties of this function are studied and using it the average photon number and its fluctuations in the amplified state are found. © 2021, Editura Academiei Romane. All rights reserved

Suppression of Spin-Orbit Scattering in Strong-Disordered Gold Nanojunctions

We discovered that spin-orbit scattering in strong-disordered gold nanojunctions is strongly suppressed relative to that in weak-disordered gold thin films. This property is unusual because in weak-disordered films, spin-orbit scattering increases with disorder. Granularity and freezing of spin-orbit scattering inside the grains explains the suppression of spin-orbit scattering. We propose a generalized Elliot-Yafet relation that applies to strong-disordered granular regime.Comment: 4 pages 4 figure

Influence of Hellebores Ingredients (Helleborus odorus Waldst. et Kit.) on Hematological Parameters, Acute Phase Proteins and Neutrophil Granulocytes Functions in Rats

U okviru ove doktorske disertacije je ispitivan uticaj sastojaka petroletarskog (PEK), hloroformskog (HEK), metanolnog (MEK) i vodenog ekstrakta (EK) rizoma i korena Helleborus odorus Waldst. et Kit. na hematološke parametre, odgovor akutne faze (brzinu sedimentacije i koncentraciju proteina akutne faze) i funkcije neutrofilnih granulocita (stepen fagocitoze i intenzitet oksidativnog praska) kod Wistar pacova. Kontrolnoj grupi je intramuskularno (IM) aplikovan sterilan fiziološki rastvor u količini od 2,5 ml/kg TM. Ogledne grupe su IM tretirane različitim ekstraktima kukureka u dozama od 50, 100 ili 200 mg/kg TM, a krv za analizu je uzimana posle 24h. Osim toga, ispitivan je i uticaj vodenog i metanolnog ekstrakta aplikovanih 24h nakon trokratnog tretmana pacova deksametazonom u dozi od 1 mg/kg TM, na uočene efekte. Ogled je izveden na ukupno 147 pacova podeljenih u 21 grupu od po 7 jedinki. Aplikovanje različitih doza (50, 100 ili 200 mg/kg TM) metanolnog i vodenog ekstrakta je dovelo do značajnog povećanja broja ukupnih leukocita, broja i procenta neutrofilnih granulocita, srazmernog primenjenoj dozi. Ove promene su bile izražene i kada se ekstrakti primenjuju 24h nakon aplikacije deksametazona. Aplikovanje ovih ekstrakata je imalo za posledicu smanjenje broja i procenta limfocita i povećanje neutrofilno/limfocitnog indeksa u svim oglednim grupama. Srednje vrednosti navedenih parametra su se neznatno menjale posle aplikovanja petroletarskog i hloroformskog ekstrakta. Ispitivani ekstrakti nisu uticali na broj i procenat monocita, ali je povećanje broja ovih krvnih elemenata registrovano kod primene MEK i EK nakon tretmana pacova deksametazonom. Upotrebljeni ekstrakti nisu ispoljili hemolitičku aktivnost, koncentracija hemoglobina je bila značajno povećana, a broj trombocita smanjen. Značajno bržu sedimentaciju u svim posmatranim intervalima su imali eritrociti pacova oglednih grupa kojima su aplikovani pojedinačni ekstrakti kukureka ili u kombinaciji sa deksametazonom, a najizraženiji efekat su ispoljili metanolni i vodeni ekstrakt. Statistički značajno smanjenje koncentracije albumina i povećanje koncentracija fibrinogena je utvrđeno nakon pojedinačnog aplikovanja MEK i EK ili u kombinaciji sa deksametazonom. Tretman oglednih grupa petroletarskim i hloroformskim ekstraktom nije uticao na koncentraciju albumina, a ispoljio je negativan efekat na koncentraciju fibrinogena. Aplikovanje MEK i EK je dovelo do značajnog povećanja koncentracije haptoglobina, a sa povećanjem aplikovane doze, povećavala se i vrednost ovog parametra. Razlika u prosečnoj vrednosti koncentracije haptoglobina kod pacova kojima je trokratno aplikovan deksametazon nije bila signifikantna u odnosu na grupe koje su dodatno tretirane navedenim ekstraktima. Upotrebljeni metanolni i vodeni ekstrakt su doveli do značajnog povećanja stepena fagocitoze i intenziteta oksidativnog praska neutrofilnih granulocita. Akutna zapaljenska reakcija se razvija 24h posle pojedinačnog aplikovanja različitih doza metanolnog i vodenog ekstrakta ili u kombinaciji sa deksametazonom, ali ne i nakon tretmana petroletarskim i hloroformskim ekstraktom.Within the framework of this PhD thesis, we investigated effects that ingredients of petroleum ether (PHE), chloroform (CHE), methanol (MHE) and aqueous extract of rhizome and root of Helleborus odorus Waldst. et Kit. (HE) might have on hematological parameter values, acute phase response (sedimentation rate and concentration of acute phase proteins) and neutrophil granulocytes functions (intensity of phagocytosis and oxidative burst) in Wistar rats. Sterile saline, in the amount of 2,5 ml/kg BW, was applied intramuscularly (IM) to the animals in a control group. The experimental groups were treated intramuscularly with different Hellebores extracts in a doses of 50, 100 or 200 mg/kg BW and blood was collected following 24 hrs. We have also investigated the influence of methanol and aqueous extracts injected 24 hrs after triple treatments of rats with dexamethasone in a dose of 1 mg/kg BW on the parameters enlisted above. The experiment was conducted on the total of 147 rats divided in 21 groups consisting of 7 animals each. Application of different MHE and HE doses (50, 100 or 200 mg/kg BW) resulted in significant increase of total leukocyte count, number and percent of neutrophil granulocytes and this efect was dose dependent. These effects were also evident 24 hrs following dexamethasone treatment. In all experimental groups, lymphocyte count and percent of lymphocytes was decreased while neutrophil/lymphocyte index was increased. Other two extracts (PHE and CHE) did not exert significant effects on the above mentioned parameters. Hellebores extracts didn't influence monocyte number and percent, but increase in their number was registered after treatment with MHE and HE following dexamethasone injections. Thrombocyte count was decreased. Applied extracts didn't exert hemolitic activity and hemoglobin concentration was significantly increased. Sedimentation rate in all observed intervals was significantly increased in all groups treated with Hellebores extracts alone or in combinations with dexamethasone. Methanol and aqueous extract exerted were the most effective. Statistically significant decrease in albumin concentration and elevation of fibrinogen concentration was registrated after single application of MHE and HE alone or in combination with dexamethasone. Treatment of experimental groups with petroleum ether and chloroform extract didn't elevate albumin concentration, and exerted negative influence on the fibrinogen concentration. Application of MHE and HE resulted in significant haptoglobin concentration increase and this effect was dose dependent. Differences in haptoglobin mean values following triple treatment with dexamethasone didn't significantly differ when compared to the values recorded in groups aditionally treated with Hellebores extracts. Intensity of phagocytosis and oxidative burst by neutrophils were significantly increased with MHE and HE. Acute inflammatory reaction developed 24 hrs following application of different MHE and HE doses alone, or in combination with dexamethasone, but not and after treatment with PHE and CHE

Spectroscopy, Interactions and Level Splittings in Au Nanoparticles

We have measured the electronic energy spectra of nm-scale Au particles using a new tunneling spectroscopy configuration. The particle diameters ranged from 5nm to 9nm, and at low energies the spectrum is discrete, as expected by the electron-in-a-box model. The density of tunneling resonances increases rapidly with energy, and at higher energies the resonances overlap forming broad resonances. Near the Thouless energy, the broad resonances merge into a continuum. The tunneling resonances display Zeeman splitting in a magnetic field. Surprisingly, the g-factors (~0.3) of energy levels in Au nano-particles are much smaller than the g-factor (2.1) in bulk gold