Gradient-free quantum optimization on NISQ devices

Variational Quantum Eigensolvers (VQEs) have recently attracted considerable attention. Yet, in practice, they still suffer from the efforts for estimating cost function gradients for large parameter sets or resource-demanding reinforcement strategies. Here, we therefore consider recent advances in weight-agnostic learning and propose a strategy that addresses the trade-off between finding appropriate circuit architectures and parameter tuning. We investigate the use of NEAT-inspired algorithms which evaluate circuits via genetic competition and thus circumvent issues due to exceeding numbers of parameters. Our methods are tested both via simulation and on real quantum hardware and are used to solve the transverse Ising Hamiltonian and the Sherrington-Kirkpatrick spin model.Comment: 13 pages, 6 figures, comments welcome

Changes in the cephalopod diet of southern elephant seal females at King George Island, during El Niño - La Niña events

Possible effects of ‘El Niño’ Southern Oscillation (ENSO) components ‘El Niño’ and ‘La Niña’ on populations of southern elephant seals, Mirounga leonina, were analysed. Changes in the cephalopod diet composition of moulting females at King George Island, Antarctic Peninsula were considered. The diet of female elephant seals sampled in 1991–1992 and 1992–1993 (El Niño years) were compared with those taken in 1995–1996 (La Niña year) at the same site and employing the same methodology. The squid Psychroteuthis glacialis constituted the main cephalopod prey of the seals. A reduction in the ‘Index of Biomass Ingested’ by female elephant seals (IBIF) of this prey species was observed in ‘El Niño’ years (1992, 1993) compared with the ‘La Niña’ year (1996). This reduction in biomass applied to all squid species in the seals' prey with the exception of Galiteuthis glacialis, which occurred in low numbers, but was more abundant during El Niño years than in the La Niña year

An ellipsoidal mirror for focusing neutral atomic and molecular beams

Manipulation of atomic and molecular beams is essential to atom optics applications including atom lasers, atom lithography, atom interferometry and neutral atom microscopy. The manipulation of charge-neutral beams of limited polarizability, spin or excitation states remains problematic, but may be overcome by the development of novel diffractive or reflective optical elements. In this paper, we present the first experimental demonstration of atom focusing using an ellipsoidal mirror. The ellipsoidal mirror enables stigmatic off-axis focusing for the first time and we demonstrate focusing of a beam of neutral, ground-state helium atoms down to an approximately circular spot, (26.8±0.5) μm×(31.4±0.8) μm in size. The spot area is two orders of magnitude smaller than previous reflective focusing of atomic beams and is a critical milestone towards the construction of a high-intensity scanning helium microscope

An ellipsoidal mirror for focusing neutral atomic and molecular beams

Manipulation of atomic and molecular beams is essential to atom optics applications including atom lasers, atom lithography, atom interferometry and neutral atom microscopy. The manipulation of charge-neutral beams of limited polarizability, spin or excitation states remains problematic, but may be overcome by the development of novel diffractive or reflective optical elements. In this paper, we present the first experimental demonstration of atom focusing using an ellipsoidal mirror. The ellipsoidal mirror enables stigmatic off-axis focusing for the first time and we demonstrate focusing of a beam of neutral, ground-state helium atoms down to an approximately circular spot, (26.8±0.5) μm×(31.4±0.8) μm in size. The spot area is two orders of magnitude smaller than previous reflective focusing of atomic beams and is a critical milestone towards the construction of a high-intensity scanning helium microscope

Relation between the plastic instability and fracture of tensile tested Cu-Sn alloys investigated with the application of acoustic emission technique

The work concerns the application of the acoustic emission (AE) method in testing the mechanical properties of continuously cast industrial tin bronze CuSn6P, which reveals tendencies to instable plastic flow connected particularly with the Portevin-Le Chatelier (PLC) effect. The relations between the jerky flow connected with the PLC effect, AE intensity and the evolution of a fracture of the investigated alloy subjected to the tensile test at a strain rate (?? ) of about 1.2·10-3s-1 in the range of temperatures (20÷400?C) has been analyzed. It has been found that the highest intensity of the oscillation of stresses, corresponding to the instability of plastic deformation PLC occurred at 200?C, whereas the maximum of the AE activity is at about 200÷250?C. The brittle intergranular fracture starts in the range of equicohersive temperature (TE) of about 200?C. Plastic deformation of the investigated alloy in the range of the temperature of minimum plasticity, amounting to about 400?C, results in intercrystalline fractures on the entire surface of the stretched samples

Evaluation of the Effects of Powder Coating Cure Temperatures on the Mechanical Properties of Aluminum Alloy Substrates

The effects of curing temperature, based on new, low-temperature powder coating methods and traditional high-temperature powder coating methods, were studied. Heat-sensitive aluminum alloys (2024-T3, 6061-T6, and 7075-T6) were subjected to two different heat-treatment cycles, which were based on temperatures of 121 and 204 degrees C. Findings indicate that although both cure temperatures achieved powder coatings adhesion and thickness appropriate for industrial uses, the high-temperature cure treatment negatively affected the mechanical properties