Abstract
Progress in the creation of large-scale, artificial quantum coherent structures demands the investigation of their nonequilibrium dynamics when strong interactions, even between remote ...parts, are non-perturbative. Analysis of multiparticle quantum correlations in a large system in the presence of decoherence and external driving is especially topical. Still, the scaling behavior of dynamics and related emergent phenomena are not yet well understood. We investigate how the dynamics of a driven system of several quantum elements (e.g., qubits or Rydberg atoms) changes with increasing number of elements. Surprisingly, a two-element system exhibits chaotic behaviors. For larger system sizes, a highly stochastic, far from equilibrium,
hyperchaotic
regime emerges. Its complexity systematically scales with the size of the system, proportionally to the number of elements. Finally, we demonstrate that these chaotic dynamics can be efficiently controlled by a periodic driving field. The insights provided by our results indicate the possibility of a reduced description for the behavior of a large quantum system in terms of the transitions between its qualitatively different dynamical regimes. These transitions are controlled by a relatively small number of parameters, which may prove useful in the design, characterization, and control of large artificial quantum structures.
•Internal friction and shear modulus data are presented for a 7 orders of magnitude frequency range.•A law describing the imaginary compliance component in this range is determined.•A new method for ...the determination of the Gibbs activation energy of relaxation is suggested.•It is argued that relaxation origin is related to the interstitial-type defects inherited from the melt.•It is assumed that at least defect-related three mechanisms of energy losses are operating.
We report measurements of the internal friction and shear modulus of glassy Cu49Hf42Al9 at sub-hertz frequencies (0.03–1 Hz) and at a high frequency of 560 kHz at temperatures from the room one up to well above the glass transition temperature Tg. It is found that an increase of the frequency in this range results in a drastic decrease of the internal friction and shear modulus relaxation both below and above Tg. The relaxation kinetics is analyzed within the framework of a classical phenomenological approach in terms of the real and imaginary parts of the dynamic shear compliance both for the initial and relaxed states of the glass under investigation. A law describing the frequency dependence of the imaginary compliance component in the whole frequency range investigated is determined. A new method for the determination of the Gibbs activation energy of relaxation is derived. The underlying activation energy spectrum determined on this basis is found to smoothly increase with the activation energies accessible in the experiment. A change of the activation energy with temperature below and above Tg is determined. The phenomenological analysis is combined with a physical interpretation of the relaxation, which is assumed taking place due to the activation of interstitial-type defects (essentially elastic dipoles) frozen-in from the melt upon glass production. It is argued that there exist at least three mechanisms of energy losses, which are related to changes of the dipoles’ orientation in the same energy states and transitions between their low- and high-energy states.
Background
Cognitive impairment is an irreversible, aging-associated condition that robs people of their independence. The purpose of this study was to investigate possible causes of this condition ...and propose preventive options.
Methods
We assessed cognitive status in long-living adults aged 90+ (
n
= 2,559) and performed a genome wide association study using two sets of variables: Mini-Mental State Examination scores as a continuous variable (linear regression) and cognitive status as a binary variable (> 24, no cognitive impairment; <10, impairment) (logistic regression).
Results
Both variations yielded the same polymorphisms, including a well-known marker of dementia, rs429358in the APOE gene. Molecular dynamics simulations showed that this polymorphism leads to changes in the structure of alpha helices and the mobility of the lipid-binding domain in the APOE protein.
Conclusion
These changes, along with higher LDL and total cholesterol levels, could be the mechanism underlying the development of cognitive impairment in older adults. However, this polymorphism is not the only determining factor in cognitive impairment. The polygenic risk score model included 45 polymorphisms (ROC AUC 69%), further confirming the multifactorial nature of this condition. Our findings, particularly the results of PRS modeling, could contribute to the development of early detection strategies for predisposition to cognitive impairment in older adults.
Photoluminescence (PL) was used to estimate the concentration of point defects in GaN. The results are compared with data from positron annihilation spectroscopy (PAS), secondary ion mass ...spectrometry (SIMS), and deep level transient spectroscopy (DLTS). Defect-related PL intensity in undoped GaN grown by hydride vapor phase epitaxy increases linearly with the concentration of related defects only up to 10
cm
. At higher concentrations, the PL intensity associated with individual defects tends to saturate, and accordingly, does not directly correlate with the concentration of defects. For this reason, SIMS analysis, with relatively high detection limits, may not be helpful for classifying unidentified point defects in GaN. Additionally, we highlight challenges in correlating defects identified by PL with those by PAS and DLTS methods.
Mathematical modeling and computer prediction of elastic, viscoelastic, and plastic deformations of polymeric textile materials are examined. Division of full deformation of polymeric textile ...materials into components helps solve the problem of determination of their functional properties.
A complete package ensemble, complex of physical and chemical investigations was conducted: x-ray phase analysis, differential thermal analysis, chemical analysis of waste generated in the production ...of vanadium. It was established that these wastes, which contain 17.39% Mn
2
O
3
in their composition, are a promising raw material for the production of wall ceramics with volumetric-staiing. The effect of heat treatment at 200, 500, 600, and 700°C on the phase composition of the wastes from the production of vanadium was investigated.
A technology was developed for producing in a plasma reactor glass microspheres using the ferruginous quartzite tailings of the Kursk Magnetic Anomaly KMA. The predictable effects of the ...plasma-forming argon-gas flow rate and the plasma reactor power on the fractional composition were determined. It is shown that on increasing the plasma-forming gas flow rate from 1.5 to 2.5 m
3
/h and the current strength from 400 to 500 A the fraction amount over 630 μm increases due to coagulation processes. It is shown that the glass microspheres are enriched in aluminum and calcium oxides and depleted of silicon, magnesium, sodium, potassium, and iron oxides. It is shown that at high plasma temperatures, of the order of 9000 – 12,000 K, the particles melt completely and spherical glass microspheres ranging in size from 80 to 1250 μm are formed. Operational metrics, such as microhardness, acid resistance, and alkali resistance, of the glass microspheres based on the ferruginous quartzite tailings of KMA were investigated.
Single crystal halide perovskites with microscale dimensions are an emerging class of objects for various advanced photonic and optoelectronic applications. Particularly, defect tolerance and ...broadband tunability of luminescence make them one of the most prospective candidates to develop microlasers for visible range. However, their post‐processing by standard nanolithography methods face a number of problems related to worsening of their properties, thus making gentle laser processing one of best solutions for perovskite patterning. Here, it is shown that femtosecond laser irradiation of single‐crystal halide perovskite CsPbBr3 allows for its precise and ultraclean ablation fully controlled at subwavelength scale by the intensity and polarization distribution of the complex laser field applied. Indeed, the extremely low thermal conductivity (over 300 times lower than that of silicon) and ultrafast thermalization rate makes it possible to reduce heat‐affected zone and avoid melting layer contribution, while the high refractive index (larger than 2) provides high spatial resolution in case of irradiation of pre‐patterned focusing perovskite nanostructures. These features allow for direct imprinting of the incident laser field at wavelength λ = 515 nm, creating micro‐lens and various light‐emitting metasurfaces with deeply subwavelength spatial resolution (down to λ/7).
Femtosecond laser irradiation of single‐crystal halide perovskite CsPbBr3 allows for its precise and ultraclean ablation fully controlled at subwavelength scale by the intensity and polarization distribution of the complex laser field applied. The direct imprinting of the incident laser field results in the creation of micro‐lens and various light‐emitting metasurfaces with deeply subwavelength spatial resolution (down to lambda/7).
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