Validation of digital holographic tomography in flow measurement

This paper reports on measurements by digital holographic tomography in flow measurement. It is demonstrated capability of the method by measurement of general temperature field consisting of system of three orifices. Results obtained by digital holographic tomography are compared to results obtained by hot wire anemometry CTA

Terahertz electrical writing speed in an antiferromagnetic memory

The speed of writing of state-of-the-art ferromagnetic memories is physically limited by an intrinsic gigahertz threshold. Recently, realization of memory devices based on antiferromagnets, in which spin directions periodically alternate from one atomic lattice site to the next has moved research in an alternative direction. We experimentally demonstrate at room temperature that the speed of reversible electrical writing in a memory device can be scaled up to terahertz using an antiferromagnet. A current-induced spin-torque mechanism is responsible for the switching in our memory devices throughout the 12-order-of-magnitude range of writing speeds from hertz to terahertz. Our work opens the path toward the development of memory-logic technology reaching the elusive terahertz band

Novi kavernikolni mravoliki kornjaš iz roda Euconnus (subg. Tetramelus) iz Hrvatske (Coleoptera: Scydmaenidae)

A new cave dwelling species of Euconnus (Tetramelus) Motschulsky is described from the Croatian cave »Bazgovačka Jama«. The relationship of the new species to the species-groups longulus and oblongus is briefly discussed and the occurrences of Tetramelus in the former Yugoslavia are concisely listed.U radu se opisuje nova špiljska vrsta iz roda Euconnus (Tetramelus) Motschulsky iz Bazgovačke Jame. Ukratko se raspravlja o odnosu nove vrste prema grupama vrsta longulus i oblongus, te se daje pregled dosadašnjeg pojavljivanja roda Tetramelus u bivšoj Jugoslaviji

Supersymmetric quantum mechanics living on topologically nontrivial Riemann surfaces

Supersymmetric quantum mechanics is constructed in a new non-Hermitian representation. Firstly, the map between the partner operators $H^{(\pm)}$ is chosen antilinear. Secondly, both these components of a super-Hamiltonian ${\cal H}$ are defined along certain topologically nontrivial complex curves $r^{(\pm)}(x)$ which spread over several Riemann sheets of the wave function. The non-uniqueness of our choice of the map ${\cal T}$ between "tobogganic" partner curves $r^{(+)}(x)$ and $r^{(-)}(x)$ is emphasized.Comment: 14p

Microbatch under-oil salt screening of organic cations: single-crystal growth of active pharmaceutical ingredients

Multicomponent solid forms of active pharmaceutical ingredients represent a modern method of tuning their physicochemical properties. Typically, salts are the most commonly used multicomponent solid form in the pharmaceutical industry. More than 38% are formulated as organic cations. Salt screening is an essential but demanding step when identifying the most appropriate formulation. The microbatch under-oil crystallization technique of proteins has been combined with the previously developed high-throughput vapour-diffusion screening for use as a novel method of primary salt screening of organic cations. The procedure allows the set up of about 100 crystallization experiments per 30 min. This requires between 17 and 564 mg of screened cationic active pharmaceutical ingredients, which were of moderate to very high water solublity. Five distinct organic salts, three of them diverse active pharmaceutical compounds or the other enantiomer thereof, in the form of chloride salts were tested. The screening was extremely successful; at least two new single-crystal structures could be obtained for each particular compound and many more salts as single crystals were formed compared with our previous vapour-diffusion method

In-situ electric field control of THz non-reciprocal directional dichroism in the multiferroic Ba2_2CoGe2_2O7_7

Non-reciprocal directional dichroism, also called the optical-diode effect, is an appealing functional property inherent to the large class of non-centrosymmetric magnets. However, the in-situ electric control of this phenomenon is challenging as it requires a set of conditions to be fulfilled: Special symmetries of the magnetic ground state, spin-excitations with comparable magnetic- and electric-dipole activity and switchable electric polarization. We demonstrate the isothermal electric switch between domains of Ba$_2$CoGe$_2$O$_7$ possessing opposite magnetoelectric susceptibilities. Combining THz spectroscopy and multiboson spin-wave analysis, we show that unbalancing the population of antiferromagnetic domains generates the non-reciprocal light absorption of spin excitations.Comment: version accepte

Self-isospectrality, special supersymmetry, and their effect on the band structure

We study a planar model of a non-relativistic electron in periodic magnetic and electric fields that produce a 1D crystal for two spin components separated by a half-period spacing. We fit the fields to create a self-isospectral pair of finite-gap associated Lame equations shifted for a half-period, and show that the system obtained is characterized by a new type of supersymmetry. It is a special nonlinear supersymmetry generated by three commuting integrals of motion, related to the parity-odd operator of the associated Lax pair, that coherently reflects the band structure and all its peculiarities. In the infinite period limit it provides an unusual picture of supersymmetry breaking.Comment: Title changed by the Editor of Phys. Rev. Lett., published versio

Solvability and PT-symmetry in a double-well model with point interactions

We show that and how point interactions offer one of the most suitable guides towards a quantitative analysis of properties of certain specific non-Hermitian (usually called PT-symmetric) quantum-mechanical systems. A double-well model is chosen, an easy solvability of which clarifies the mechanisms of the unavoided level crossing and of the spontaneous PT-symmetry breaking. The latter phenomenon takes place at a certain natural boundary of the domain of the "acceptable" parameters of the model. Within this domain the model mediates a nice and compact explicit illustration of the not entirely standard probabilistic interpretation of the physical bound states in the very recently developed (so called PT symmetric or, in an alternative terminology, pseudo-Hermitian) new, fairly exciting and very quickly developing branch of Quantum Mechanics.Comment: 24 p., written for the special journal issue "Singular Interactions in Quantum Mechanics: Solvable Models". Will be also presented to the int. conference "Pseudo-Hermitian Hamiltonians in Quantum Physics III" (Instanbul, Koc University, June 20 - 22, 2005) http://home.ku.edu.tr/~amostafazadeh/workshop/workshop.ht