In social networking services, users constantly change, and the network structure changes simultaneously. As the network structure changes, so does the word-of-mouth within it. To study how information transfer on the...
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We consider some of the main notions of Gibbs measures on subshifts introduced by different communities, such as dynamical systems, probability, operator algebras, and mathematical physics. For potentials with d-summa...
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We report on the chemical structure and spin Hall magnetoresistance (SMR) in epitaxial α−Fe2O3(hematite)(0001)/Pt(111) bilayers with hematite thicknesses of 6 and 15 nm grown by molecular beam epitaxy on a MgO(111) s...
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We report on the chemical structure and spin Hall magnetoresistance (SMR) in epitaxial α−Fe2O3(hematite)(0001)/Pt(111) bilayers with hematite thicknesses of 6 and 15 nm grown by molecular beam epitaxy on a MgO(111) substrate. Unlike previous studies that involved Pt overlayers on hematite, the present hematite films were grown on a stable Pt buffer layer and displayed structural changes as a function of thickness. These structural differences (the presence of a ferrimagnetic phase in the thinner film) significantly affected the magnetotransport properties of the bilayers. We observed a sign change of the SMR from positive to negative when the thickness of the hematite increased from 6 to 15 nm. For α−Fe2O3(15nm)/Pt, we demonstrated room-temperature switching of the Néel order with rectangular, nondecaying switching characteristics. Such structures open the way to extending magnetotransport studies to more complex systems with double asymmetric metal/hematite/Pt interfaces.
The development of power electronic devices and advances in control engineering made the application of sophisticated control algorithms possible. The state of the art solution assumes that each device has an integrat...
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We study strong-field double ionization in a three-electron atom by applying a simplified, reduced-dimensionality model with three active electrons. The influence of the spin-induced symmetry of the spatial part of th...
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We study strong-field double ionization in a three-electron atom by applying a simplified, reduced-dimensionality model with three active electrons. The influence of the spin-induced symmetry of the spatial part of the wave function on the final two-photoelectron momentum distribution is discussed. We identify partial momentum distributions originating from different sets of spins of outgoing electrons providing in this way a quantum support connection between the V-structure and direct ionization typically explained classically. Changes in the momentum distribution with increasing field amplitude obtained in our simplified model are shown to be well correlated with the experimental data known from the literature. The possible relation between the observed dependencies and different ionization mechanisms is discussed.
We are exploring two archetypal noise-induced escape scenarios: Escape from a finite interval and from the positive half-line under the action of the mixture of Lévy and Gaussian white noises in the overdamped re...
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We are exploring two archetypal noise-induced escape scenarios: Escape from a finite interval and from the positive half-line under the action of the mixture of Lévy and Gaussian white noises in the overdamped regime, for the random acceleration process and higher-order processes. In the case of escape from finite intervals, the mixture of noises can result in the change of value of the mean first passage time in comparison to the action of each noise separately. At the same time, for the random acceleration process on the (positive) half-line, over the wide range of parameters, the exponent characterizing the power-law decay of the survival probability is equal to the one characterizing the decay of the survival probability under action of the (pure) Lévy noise. There is a transient region, the width of which increases with stability index α, when the exponent decreases from the one for Lévy noise to the one corresponding to the Gaussian white noise driving.
In this paper, an automated design procedure of a cascoded-inverter-based charge-sensitive amplifier (CSA) using the g m /I D method and particle swarm optimization (PSO) is presented. Assuming certain fixed values, ...
In this paper, an automated design procedure of a cascoded-inverter-based charge-sensitive amplifier (CSA) using the g m /I D method and particle swarm optimization (PSO) is presented. Assuming certain fixed values, such as transistors' length, supply voltage, feedback resistance, and input, output and feedback capacitances, the algorithm is able to find the proper transistors' width and cascode biasing voltages, to meet specified requirements, such as power consumption, gain, bandwidth, input/output DC level and input-referred noise. A CSA designed in 28 nm CMOS technology using the presented method achieves 500 V/V gain, 3.7 MHz bandwidth and 71e − ENC, consuming 2.2 μW of power from a 1.1 V supply.
We consider the gauge invariant version of the Proca theory, where besides the real vector field there is also the real scalar field. We quantize the theory such that the commutator of the scalar field operator and th...
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We consider the gauge invariant version of the Proca theory, where besides the real vector field there is also the real scalar field. We quantize the theory such that the commutator of the scalar field operator and the electric field operator is given by a predefined three-dimensional vector field, say E up to a global prefactor. This happens when the field operators of the gauge invariant Proca theory satisfy the proper gauge constraint. In particular, we show that E given by the classical Coulomb field leads to the Coulomb gauge constraint making the vector field operator divergenceless. We also show that physically unreadable gauge constraints can have a strikingly simple E-representation in our formalism. This leads to the discussion of Debye, Yukawa, etc. gauges. In general terms, we explore the mapping between classical vector fields and gauge constraints imposed on the operators of the studied theory.
We investigate the energy spectrum of a single- and two-electron quantum dot (QD) embedded in two-dimensional electron gas at the interface between SrTiO3 and LaAlO3, in the presence of the external magnetic field. Fo...
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We investigate the energy spectrum of a single- and two-electron quantum dot (QD) embedded in two-dimensional electron gas at the interface between SrTiO3 and LaAlO3, in the presence of the external magnetic field. For this purpose, the three-band model of 3d electrons defined on the square lattice of Ti ions was utilized. We demonstrate that, for the weak parabolic confinement potential, the low-energy spectrum is sufficiently well described by the effective Hamiltonian reduced to the one dxy orbital with the spin-orbit interaction originating from the coupling to the dxz and dyz bands. This is not the case for stronger confinement where contribution of the states related to the dxz/yz orbital is relevant. Based on the time-dependent calculations, we discuss in detail the manipulation of the electron spin in a QD by external AC voltages, in the context of the electric dipole spin resonance. The allowed and forbidden transitions are discussed in detail with respect to the parity selection rule. Our calculations show that, for a single-electron QD, the spin flip in the ground state has the character of a Rabi resonance, while for two electrons, the singlet-triplet transition is forbidden by the parity symmetry. For the two-electron QD, we demonstrate that the spin-flip transition can still be accomplished via a second-order, two-photon process that has a two-state Rabi character for low AC field amplitude. The violation of the parity symmetry on the spin-flip transitions is also analyzed.
This paper summarizes the design of a prototype integrated circuit for hybrid pixel X-ray detectors fabricated in 28 nm CMOS technology. The chip consists of 32 pixels with dimensions 50 μ m: × 50 μm each. Each...
This paper summarizes the design of a prototype integrated circuit for hybrid pixel X-ray detectors fabricated in 28 nm CMOS technology. The chip consists of 32 pixels with dimensions 50 μ m: × 50 μm each. Each pixel is divided into three sections: a front-end, two-ring oscillators with their frequency control circuits, and a digital part. It offers singlephoton counting functionality as well as in-pixel time measurement. In previous papers, a detailed design of the chip and simulation results were reported, and an approach was described that utilized System Verilog language together with the AMS simulator for the verification of this asynchronous, mixed-mode circuitry. This paper focuses more on testing fabricated chips. It describes a test setup and PCB design and mentions how the prior System Verilog verification approach helped with the development of a testing software. Finally, preliminary measurement results are presented that illustrate the performance of front-end and oscillators.
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