Observing Parity Time Symmetry Breaking in a Josephson Parametric Amplifier

A coupled two-mode system with balanced gain and loss is a paradigmatic example of an open quantum system that can exhibit real spectra despite being described by a non-Hermitian Hamiltonian. We utilize a degenerate parametric amplifier operating in three-wave mixing mode to realize such a system of balanced gain and loss between the two quadrature modes of the amplifier. By examining the time-domain response of the amplifier, we observe a characteristic transition from real-to-imaginary energy eigenvalues associated with the Parity-Time-symmetry-breaking transition.Comment: 6 pages, 4 figure

Extraction and separation of mercury(II) from succinate media with high molecular weight amine as an extractant

The extraction of mercury(II) from succinate solutions by 2-octylaminopyridine (2-OAP) has been studied by metal distribution measurements. The optimum extraction conditions were determined from a critical study of effects of pH, sodium succinate concentration and 2-octylaminopyridine concentration. The probable composition of the species has been deduced from log–log plots. The extraction reaction proceeds with ion-pair formation and the stoichiometry of extracted species was found to be [(2OAPH+)2 Hg(Succinate)22−](org). The method has been used to separate mercury(II) from commonly associated elements. The method has been further extended to separate and to estimate mercury in synthetic mixtures and real samples

Calixarene Intercalated NiCo Layered Double Hydroxide for Enhanced Oxygen Evolution Catalysis

Water splitting provides a promising, sustainable way to resolve problems arising due to depleting fossil fuels. The success needs development of low-cost and high-performance electrode materials. The oxygen evolution reaction (OER) is a crucial reaction in water splitting. The combined Ni and Co oxide developed nanostructures having a small overpotential and fast kinetics of OER. They have drawn considerable attention, because of their theoretically high efficiency, high abundance, low cost, and environmental benignity in comparison with precious metal oxides, such as RuO₂ and IrO₂. However, the desired efficiency needs the developments of enhanced specific active area and conductivity. In the present communication, we address these issues. Specifically, exfoliation of layer double hydroxide (LDH) is applied to enhance the active surface area. The study reveals that intercalation by calixarene in NiCo LDH affords a multifunctional interlayer to deliver a large active surface area and fast electron transport toward the carbon nano-onion (CNO) support. It favorably lowers the overpotentials in OER (290 mV) and  attains Tafel slope of 31 mV/decade. Enhanced conductivity is achieved using CNO as a support for the calixarene intercalated NiCo LDH. These developments offer a synergistic effect in achieving superior electrocatalytic activity for OER. This work gives insight into designing binder-free electrodes in alkaline media with good stability for advanced OER activity