The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics

Quantum discord plays a pragmatic role in analyzing nonclassical feature of quantum correlations beyond entanglement. It is used in several information processing protocols which lacks sufficient amount of entanglement to be used as a resource. We have provided with an analytical method of detecting quantum discord of an arbitrary two qubit state. We have formulated a set of necessary and sufficient conditions for any two qubit state to be a both-way non-zero quantum discord state. As quantum discord is asymmetric in nature, we have framed the set of if and only if conditions for a two qubit state to be classical-quantum as well for it to be quantum-classical. Interestingly, not only correlation tensor but also local Bloch vector (corresponding to the classical party) plays a role for detecting the state to be a positive discord state.

Using a kinematic approach we show that the non-adiabatic, non-cyclic, geometric phase corresponding to the radiation emitted by a three level cascade system provides a sensitive diagnostic tool for determining the entanglement properties of the two modes of radiation. The nonunitary, noncyclic path in the state space may be realized through the same control parameters which control the purity/mixedness and entanglement. We show analytically that the geometric phase is related to concurrence in certain region of the parameter space. We further show that the rate of change of the geometric phase reveals its resilience to fluctuations only for pure Bell type states. Lastly, the derivative of the geometric phase carries information on both purity/mixedness and entanglement/separability.

The Pick Up technique allows continuous formation of high density metal cluster beams in the otherwise hardly accessible size range Me2 to about Me50. With an apparatus based on the use of cryo-condensation pumps, Ar as inert gas for production of the host clusters by adiabatic expansion and silver as metal we demonstrate how the various source parameters influence the composition and mean size of the resulting cluster distributions. The analysis in the gas phase by means fluorescence spectroscopy allows to conclude that an Ar shell encapsulates the metal clusters.

Using a high resolution electron energy monochromator low energy electron attachment to formic acid is studied for the first time by means of mass spectrometric detection of the product anions. The largest dissociative electron attachment (DA) cross-section produces HCOO -+H with weaker channels for OH- and O- becoming apparent at higher incident energies.

A new coumarin-fused quinoline push–pull fluorescent probe was designed, synthesized and characterized using $$^{\mathrm {1}}$$ H NMR, $$^{\mathrm {13}}$$ C NMR and mass spectrometry analysis. Electronic absorption and fluorescence studies of the synthesized probe were investigated in wide range of solvents of varying polarities, and the data were used to study its solvatochromic properties. The ground and excited state dipole moments of fluorescent probe were obtained from Bakhshiev’s and Bilot–Kawasaki’s equations by means of the solvatochromic shift method. The high value of dipole moment for the excited state over ground-state value was attributed to more polar excited state of molecule. Also, emission peak undergoes a bathochromic shift with an increase in the polarity of the solvent, confirming $${\varvec{\pi }} \rightarrow {\varvec{\pi }}{} \mathbf * $$ transition. The ground-state and excited-state dipole moments were calculated and compared using DFT calculations. Both experimental and computational studies revealed that excited-state dipole moment values are higher than corresponding ground-state value of studied compound. A new coumarin-fused quinoline push–pull fluorescent probe was designed, synthesized and characterized. The ground-state and excited-state dipole moments were calculated and compared using DFT calculations.

Non-thermal electrical discharges, such as corona discharge are apart of the source of ozone, charged, and excited species and acoustic noise also the source of electromagnetic radiation of different wavelengths. The important component of this radiation from the standpoint of photocatalyst activation is the ultraviolet radiation. We studied the role of UV radiation on corona discharge ozone production by placing the titanium dioxide photocatalyst into the discharge region. We used hollow needle to mesh DC corona discharge at atmospheric pressure with TiO2 globules on the mesh. The discharge was enhanced by the flow of air through the needle. We found that for the needle biased negatively addition of TiO2 photocatalyst on the mesh electrode drastically increases discharge ozone production as well as the ozone production yield. These quantities are also influenced by the mass of the used photocatalyst and its distribution in the discharge chamber.