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This article presents a power-efficient low-jitter fractional-N digital phase-locked loop (DPLL) that resolves phase error (PE) in the fully differential voltage (FDV) domain. Compared with adopting a traditional time-to-digital converter (TDC), which relies on gate delay in the time domain, power-efficient quantization of PE by the proposed conversion scheme in the FDV domain can be accomplished with a higher power-supply/common-mode rejection ratio (PSRR/CMRR), lower process, voltage, and temperature (PVT) sensitivity, finer resolution, and better linearity. The implemented DPLL covers the fractional-N operation by a 10-bit differential current digital-to-analog converter (DAC) with a resistive load to represent the fractional phase/time. A differential dv/dt ramp is employed to linearly transfer the preset initial voltage into a small phase/voltage error, which is digitized by a narrow-range fine-resolution 7-bit self-timed successive-approximation-register analog-to-digital converter (SAR-ADC). The prototype DPLL, implemented in 130-nm CMOS, achieves 101-fs rms jitter, integrated from 10 kHz to 40 MHz, in the fractional-N mode with sub-12-bit fractional-frequency-control words, using an 80-MHz reference clock (REF), consuming 9.2 mW. This corresponds to a figure of merit (FoM) of −250.3 dB. The measured worst case fractional spur level is −56 dBc. [ABSTRACT FROM AUTHOR]

We consider two models where the wave equation can be reduced to the effective Schrödinger equation whose potential contains both harmonic and the Coulomb terms, |$\omega^{2}r^{2}-a/r$|⁠. The equation reduces to the biconfluent Heun's equation, and we find that the charge as well as the energy must be quantized and state-dependent. We also find that two quantum numbers are necessary to count radial degrees of freedom and suggest that this is a general feature of differential equation with higher singularity like the Heun's equation. [ABSTRACT FROM AUTHOR]

Graphene and carbon nanotubes are materials with large potentials for applications in flexible electronics. Such devices require a high level of sustainable strain and an understanding of the materials electrical properties under strain. Using supercell theory in conjunction with a comprehensive molecular mechanics model, the full band phonon dispersion of carbon nanotubes under uniaxial strain is studied. The results suggest an overall phonon softening and open up the possibility of phonon quantization tuning with uniaxial strain. The change in phonon quantization and the resulting increase in electron-phonon and phonon-phonon scattering rates offer further explanation and theoretical basis to the experimental observation of electrical properties degradation for carbon nanotubes under uniaxial strain. [ABSTRACT FROM AUTHOR]

We present mixed quantum classical calculations of the proton transfer (PT) reaction rates represented by a double well system coupled to a dissipative bath. The rate constants are calculated within the so called nontraditional view of the PT reaction, where the proton motion is quantized and the solvent polarization is used as the reaction coordinate. Quantization of the proton degree of freedom results in a problem of non-adiabatic dynamics. By employing the reactive flux formulation of the rate constant, the initial sampling starts from the transition state defined using the collective reaction coordinate. Dynamics of the collective reaction coordinate is treated classically as over damped diffusive motion, for which the equation of motion can be derived using the path integral, or the mixed quantum classical Liouville equation methods. The calculated mixed quantum classical rate constants agree well with the results from the numerically exact hierarchical equation of motion approach for a broad range of model parameters. Moreover, we are able to obtain contributions from each vibrational state to the total reaction rate, which helps to understand the reaction mechanism from the deep tunneling to over the barrier regimes. The numerical results are also compared with those from existing approximate theories based on calculations of the non-adiabatic transmission coefficients. It is found that the two-surface Landau-Zener formula works well in calculating the transmission coefficients in the deep tunneling regime, where the crossing point between the two lowest vibrational states dominates the total reaction rate. When multiple vibrational levels are involved, including additional crossing points on the free energy surfaces is important to obtain the correct reaction rate using the Landau-Zener formula. [ABSTRACT FROM AUTHOR]

In this paper, we extend the previously introduced Post-Quantization Constraints (PQC) procedure [G. Guillon, T. Zeng, and P.-N. Roy, J. Chem. Phys. 138, 184101 (2013)] to construct approximate propagators and energy estimators for different rigid body systems, namely, the spherical, symmetric, and asymmetric tops. These propagators are for use in Path Integral simulations. A thorough discussion of the underlying geometrical concepts is given. Furthermore, a detailed analysis of the convergence properties of the density as well as the energy estimators towards their exact counterparts is presented along with illustrative numerical examples. The Post-Quantization Constraints approach can yield converged results and is a practical alternative to so-called sum over states techniques, where one has to expand the propagator as a sum over a complete set of rotational stationary states [as in E. G. Noya, C. Vega, and C. McBride, J. Chem. Phys. 134, 054117 (2011)] because of its modest memory requirements. [ABSTRACT FROM AUTHOR]

A quantum scalar field inside the horizon of the non-rotating BTZ black hole is studied. Not only the near-horizon modes but also the normal modes deep inside the horizon are obtained. It is shown that the matching condition for the normal modes of a scalar field at the horizon does not uniquely determine the normal-mode expansion of a scalar field inside the horizon. By choosing a certain appropriate prescription for removing this ambiguity, an integral form of a new scalar propagator for points on both sides of the horizon are obtained. A similar problem may arise in higher-dimensional black holes. [ABSTRACT FROM AUTHOR]

In this paper, a new high-performance lossy compression technique based on DCT is proposed. The image is partitioned into blocks of a size of NxN (where N is multiple of 2), each block is categorized whether it is high frequency (uncorrelated block) or low frequency (correlated block) according to its spatial details, this done by calculating the energy of block by taking the absolute sum of differential pulse code modulation (DPCM) differences between pixels to determine the level of correlation by using a specified threshold value. The image blocks will be scanned and converted into 1D vectors using horizontal scan order. Then, 1D-DCT is applied for each vector to produce transform coefficients. The transformed coefficients will be quantized with different quantization values according to the energy of the block. Finally, an enhanced entropy encoder technique is applied to store the quantized coefficients. To test the level of compression, the quantitative measures of the peak signal-to-noise ratio (PSNR) and compression ratio (CR) is used to ensure the effectiveness of the suggested system. The PSNR values of the reconstructed images are taken between the intermediate range from 28dB to 40dB, the best attained compression gain on standard Lena image has been increased to be around (96.60 %). Also, the results were compared to those of the standard JPEG system utilized in the “ACDSee Ultimate 2020” software to evaluate the performance of the proposed system. [ABSTRACT FROM AUTHOR]

How can discrete pitches and chords emerge from the continuum of sound? Using a quantum cognition model of tonal music, we prove that the associated Schrödinger equation in Fourier space is invariant under continuous pitch transpositions. However, this symmetry is broken in the case of transpositions of chords, entailing a discrete cyclic group as transposition symmetry. Our research relates quantum mechanics with music and is consistent with music theory and seminal insights by Hermann von Helmholtz. [ABSTRACT FROM AUTHOR]

Kohn and Luttinger [Phys. Rev. 118, 41 (1960)] showed that the conventional finite-temperature extension of the second-order many-body perturbation theory had the incorrect zero-temperature limit in metals and, on this basis, argued that the theory was incorrect. We show that this inconsistency arises from the noninclusion of the temperature effect in the energies of the zeroth-order eigenstates of the perturbation theory, which causes not only the Kohn-Luttinger conundrum but also another inconsistency with the zero-temperature many-body perturbation theory, namely, the different rates of divergence of the correlation energy in a homogeneous electron gas (HEG). We propose a renormalized many-body perturbation theory derivable from the finite-temperature extension of the normal-ordered second quantization applied to the denominators of the energy expression, which involves the energies of the zeroth-order states, as well as to the numerators. The renormalized theory is shown to have the correct zero-temperature limit and the same rate of divergence in a HEG as the zero-temperature counterpart, and is, therefore, the correct finite-temperature many-body perturbation theory. [ABSTRACT FROM AUTHOR]

We present a formulation of quantized Hamiltonian dynamics (QHD) using variables that arise naturally from the Heisenberg equation of motion. The QHD equations are obtained and solved either directly in terms of these generalized variables, or by employing a wavefunction ansatz. The approach avoids a Taylor expansion and other approximations to the potential, leading to more stable dynamics and a higher precision of the calculated quantities. The proposed formulation is also amenable to for analytic and numerical implementations, thus facilitating its use in molecular dynamics simulation. [ABSTRACT FROM AUTHOR]

A new classical model for the general second-quantized many-electron Hamiltonian in Cartesian coordinates and momenta is presented; this makes semiclassical (SC) calculations using an initial value representation (IVR) more useful than the classical Hamiltonian in action-angle variables given earlier by Miller and White [J. Chem. Phys. 84, 5059-5066 (1986)]. If only 1-electron terms are included in this Hamiltonian, the classical equations of motion for the Cartesian variables are linear, and the SC-IVR gives exact results for the propagator (and thus for transition probabilities, the energy spectrum, etc.), as confirmed by analytic proof and numerical calculations. Though this new Hamiltonian is not exact when 2-electron interactions are included, we observe good results for the SC-IVR transition probabilities for times that are not too long. Test calculations, for example, show that the SC-IVR is accurate for times long enough to obtain good result for the eigenvalue spectrum (i.e., the energy levels of the electronic system). [ABSTRACT FROM AUTHOR]

It is standardly claimed in loop quantum gravity (LQG) that spacetime both disappears, fundamentally, and emerges from spin-networks in the low energy regime. In this paper, I critically explore these claims and develop a variety of substantival and relational interpretations of LQG for which these claims are false. According to most of the interpretations I consider, including the "received interpretation", it is in fact false that spacetime emerges from spin-networks. In the process of supporting these claims, I also explain why spacetime is thought to be missing from the theory's fundamental ontology and demonstrate how this conclusion depends on our interpretation of the theory. In fact, I will argue that for a variety of interpretations spacetime survives quantization just as the electromagnetic field survives quantization. The upshot of the following analysis is a much needed clarification of the ontology of LQG and how it relates, or fails to relate, to the spacetime of general relativity. • Explicate the formal structure of LQG with an eye towards its ontology. • Explain why spacetime is thought to go missing from the theory's fundamental ontology. • Dispel common misconceptions about the status of the manifold in LQG. • Provide a series of novel and ontologically consistent interpretations of LQG. • Spacetime fails to emerge either because spacetime does not disappear or because there are no spin-networks. [ABSTRACT FROM AUTHOR]

We study the stochastic cubic nonlinear Schrödinger equation (SNLS) with an additive noise on the one-dimensional torus. In particular, we prove local well-posedness of the (renormalized) SNLS when the noise is almost space–time white noise. We also discuss a notion of criticality in this stochastic context, comparing the situation with the stochastic cubic heat equation (also known as the stochastic quantization equation). [ABSTRACT FROM AUTHOR]

To reduce the detection failure of the exchanging signal power onto the OFDM subcarrier signal at uniform quantization, dynamic subcarrier mapping is applied. Moreover, to addressing low SNR's wall less than predetermine threshold, non-uniform quantization or adaptive quantization for the signal quantization size parameter is proposed. µ-law is adopted for adaptive quantization subcarrier mapping which is deployed in mobility environment, such as Doppler Effect and Rayleigh Fading propagation. In this works, sensing node received signal power then sampled into a different polarity positive and negative in µ-law quantization and divided into several segmentation levels. Each segmentation levels are divided into several sub-segment has representing one tone signal subcarrier number OFDM which has the number of quantization level and the width power. The results show that by using both methods, a significant difference is obtained around 8 dB compared to those not using the adaptive method. [ABSTRACT FROM AUTHOR]

The problem of time in the quantization of gravity arises from the fact that time in Schrödinger's equation is a parameter. This sets time apart from the spatial coordinates, represented by operators in quantum mechanics (QM). Thus "time" in QM and "time" in general relativity (GR) are seen as mutually incompatible notions. The introduction of a dynamical time operator in relativistic quantum mechanics (RQM), that follows from the canonical quantization of special relativity and that in the Heisenberg picture is also a function of the parameter t (identified as the laboratory time), prompts to examine whether it can help to solve the disfunction referred to above. In particular, its application to the conditional interpretation of time in the canonical quantization approach to quantum gravity is developed. [ABSTRACT FROM AUTHOR]

With the advent of massive MIMO and mmWave, Antenna selection is the new frontier in hybrid beamforming employed in 5G base stations. Tele-operators are reworking on the components while upgrading to 5G where the antenna is a last-mile device. The burden on the physical layer not only demands smart and adaptive antennas but also an intelligent antenna selection mechanism to reduce power consumption and improve system capacity while degrading the hardware cost and complexity. This work focuses on reducing the power consumption and finding the optimal number of RF chains for a given millimeter wave massive MIMO system. At first, we investigate the power scaling method for both perfect Channel State Information (CSI) and imperfect CSI where the power is reduced by 1/Nr and 1/√Nr respectively. We further propose to reduce the power consumption by emphasizing on the subdued resolution of Analog-to-Digital Converters (ADCs) with quantization awareness. The proposed algorithm selects the optimal number of antenna elements based on the resolution of ADCs without compromising on the quality of reception. The performance of the proposed algorithm shows significant improvement when compared with conventional and random antenna selection methods. [ABSTRACT FROM AUTHOR]

In this paper, a novel adaptive fuzzy controller is developed for the uncertain fractional-order switched nonlinear systems whose output is quantized by a class of sector-bounded quantizers. Since the states are not completely measurable, an observer with quantized output signal is designed to estimate the unknown system states. Meanwhile, based on the fractional Lyapunov stability criterion, the Lyapunov function with sum functions and the virtual control function with hyperbolic tangent functions are designed. Besides, in order to improve the approximation accuracy of the unknown nonlinear functions generated by fractional differential, the prediction errors and auxiliary variables of series-parallel estimation model are introduced in backstepping procedures. The simulation results show that the control scheme ensures that all the signals of the considered system remain semi-globally uniformly ultimately bounded, and the tracking error converges to a small neighborhood of the origin regardless of arbitrary switching. [ABSTRACT FROM AUTHOR]

The propagation characteristics of solitary wave in a degenerate plasma in the presence of Landau-quantised magnetic field and heavy negative ion are studied. The nature of solitary wave in such plasma under the influence of magnetic quantisation and the concentration of both electrons and negative ions, as well as in the presence of degenerate temperature, are studied with the help of a time-independent analytical scheme of the solution of Zakharov–Kuznetsov equation. The electron density, as well as the magnetic quantisation parameter, has an outstanding effect on the features of solitary wave proliferation in such plasma. Interestingly, for any fixed electron density, the magnetic quantisation parameter has an equal control on the maximum height and dispersive properties of the solitary wave. Toward higher temperatures and higher magnetic fields, the width of the solitary wave decreases. For a lower magnetic field, the maximum amplitude of the solitary wave decreases rapidly at higher values of degenerate temperature and negative ion concentration; however, at a lower value of degenerate temperature, the maximum amplitude increases with increasing negative ion concentration. [ABSTRACT FROM AUTHOR]

This paper discusses about the scatter of the intensity of vibration signals of paper prints and analyses their mechanical parameters applying the theory of covariance functions. It is an important practical problem, before starting printing process of colour prints, expecting the correct position of fixed raster points, to adjust the paper sheet tension between printing machine sections. The results of measuring the intensity of vibration signals at the fixed points were presented on a time scale in the form of arrays (matrices). The estimates of cross-covariance functions between digital arrays result in measuring the intensity of vibrations, and the estimates of auto-covariance functions of single arrays were calculated upon changing the quantization interval on the time scale. Application of normed auto-covariance and crosscovariance functions enables reduction of preprinting experimental measurements, which saves time (what is actual for industry). Tension force depends on the mechanical properties of the paper sheet and print. These characteristics depend on paper type, layers of printing colors and positioning of the coverage. In the calculation, the software Matlab 7 in batch statement environment was applied.

This paper investigates the dissipative interval type-2 (IT2) fuzzy control issue for a group of uncertain nonlinear systems subject to randomly occurring sensor saturation and quantization. By utilizing the both lower and upper membership functions with relevant tradeoff moduli, uncertainties, which exist in the considered systems, can be captured effectively. During the design of the IT2 fuzzy controller, we take the actuator failure into consideration. Considering the randomicities for the occurrences of sensor saturation and quantization, two separate Bernoulli stochastic distributed courses are utilized to construct the corresponding complicated transmission route. In term of Lyapunov stability theory, sufficient criteria to design dissipative IT2 fuzzy controller are presented to assure the stochastic stability with strict dissipativity of resulting closed-loop systems. Finally, illustrative example verifies the effectiveness and merits of the control strategy proposed in this paper. [ABSTRACT FROM AUTHOR]

In this article, an efficient technique is introduced to extract the quantization noise of a multi-phase voltage-controlled oscillator (VCO)-based quantizer (VCOQ) in the time domain as a pulsewidth modulated (PWM) signal. Using this technique, a new highly linear VCO-based 1-1 multi-stage noise shaping (MASH) delta–sigma analog-to-digital converter (ADC) structure is presented. This architecture does not require any operational transconductance amplifier (OTA)-based analog integrators or power-hungry linearization methods. The first stage is a closed-loop multi-phase VCO-based voltage-to-phase (V-to-P) converter, and the second stage is an open-loop multi-phase VCO-based voltage-to-frequency (V-to-F) converter. Using the proposed technique, the phase quantization error of the first stage is extracted as a pulse signal and then fed to the second stage. The input of the first VCO is a very small amplitude signal, and the input of the second VCO is a two-level PWM signal. Therefore, the VCO non-linearity does not limit the overall ADC performance, mitigating the need for power-hungry linearization methods. The prototype achieves second-order noise shaping with a DR/SFDR/SNR/SNDR of 82.7/88.7/80.3/79.7 dB for an input signal BW of 2 MHz. The fabricated design consumes 1.248 mW from a 0.9-V supply. [ABSTRACT FROM AUTHOR]

We give a brief overview how to couple general relativity to the Standard Model of elementary particles, within the higher gauge theory framework, suitable for the spinfoam quantization procedure. We begin by providing a short review of all relevant mathematical concepts, most notably the idea of a categorical ladder, 3-groups and generalized parallel transport. Then, we give an explicit construction of the algebraic structure which describes the full Standard Model coupled to Einstein-Cartan gravity, along with the classical action, written in the form suitable for the spinfoam quantization procedure. We emphasize the usefulness of the 3-group concept as a superior tool to describe gauge symmetry, compared to an ordinary Lie group, as well as the possibility to employ this new structure to classify matter fields and study their spectrum, including the origin of fermion families. [ABSTRACT FROM AUTHOR]

Majorana zero modes (MZMs) are spatially localized, zero-energy fractional quasiparticles with non-Abelian braiding statistics that hold promise for topological quantum computing. Owing to the particle-antiparticle equivalence, MZMs exhibit quantized conductance at low temperature. By using variable-tunnel–coupled scanning tunneling spectroscopy, we studied tunneling conductance of vortex bound states on FeTe0.55Se0.45 superconductors. We report observations of conductance plateaus as a function of tunnel coupling for zero-energy vortex bound states with values close to or even reaching the 2e2/h quantum conductance (where e is the electron charge and h is Planck’s constant). By contrast, no plateaus were observed on either finite energy vortex bound states or in the continuum of electronic states outside the superconducting gap. This behavior of the zero-mode conductance supports the existence of MZMs in FeTe0.55Se0.45. [ABSTRACT FROM AUTHOR]

Magnetic flux quantization is one of the defining properties of a superconductor. We report the observation of half-integer magnetic flux quantization in mesoscopic rings of superconducting b-Bi2Pd thin films. The half-quantum fluxoid manifests itself as a p phase shift in the quantum oscillation of the superconducting critical temperature. This result verifies unconventional superconductivity of b-Bi2Pd and is consistent with a spin-triplet pairing symmetry. Our findings may have implications for flux quantum bits in the context of quantum computing. [ABSTRACT FROM AUTHOR]

We show the procedure for the secondary quantization of the electromagnetic field in an inhomogeneous medium, based on the formalism of the scattering matrix. We demonstrate the electromagnetic field profiles, which are obtained as a result of applying the scattering matrix formalism and prove their orthogonality. Finally, we derive the Hamiltonian of the system. The obtained procedure allows us to use more complete representation of quantum theory in a layered medium to describe various effects in layered structures. [ABSTRACT FROM AUTHOR]

This paper investigates the output feedback $ {\mathcal {H}_{\infty }}$ control problem for a class of continuous-time nonlinear systems with both output and input quantization. The nonlinear plant is represented by a Takagi–Sugeno fuzzy model. The measurement output and the control input signals will be quantized by dynamic quantizers. The attention of this paper is focused on the design of the output feedback controller and quantizers such that the fuzzy closed-loop system is asymptotically stable and also achieves a prescribed $ {\mathcal {H}_{\infty }}$ noise attenuation level with respect to the effect of quantization. In the presence of quantization, two novel $ {\mathcal {H}_{\infty }}$ performance analysis criteria are presented for the considered fuzzy systems based on the descriptor representation approach. Then, sufficient conditions for the existence of the feedback $ {\mathcal {H}_{\infty }}$ controller gain and the quantizers’ dynamic parameters are expressed in terms of linear matrix inequalities. An adjusting scheme on quantizers’ parameters is proposed for the fuzzy system. Simulation examples are provided to show the effectiveness of the proposed design method. [ABSTRACT FROM AUTHOR]

Si and Ge nanocrystals (nc-Si and nc-Ge) with average sizes in the range of 6 and 6.3 nm, embedded in SiO2/GeO2 matrix, were fabricated and their acoustic-phonon vibrational properties were investigated using two different approaches by considering the elastic continuum model and fixed boundary condition. The breathing and quadrupolar modes are found in the spectra. The presence of medium significantly affects the phonon peaks and results into the broadening of the modes which is more in the case of elastically similar materials. The phonon line width is found to depend inversely on the size, similar to that reported experimentally. Using first and second-order optical modes, the electron-phonon coupling strengths have been estimated. The result shows that e-p coupling strength is more in the case of elastically dissimilar materials. [ABSTRACT FROM AUTHOR]

We demonstrate theoretically that it may be possible to encode states of a multi-qubit system into the progression of quantized motional/vibrational levels of an ion trapped in a weakly anharmonic potential. Control over such register of quantum information is achieved by applying oscillatory radio-frequency fields shaped optimally for excitation of the desired state-to-state transitions. Anharmonicity of the vibrational spectrum plays a key role in this approach to the control and quantum computation, since it allows resolving different state-to-state transitions and addressing them selectively. Optimal control theory is used to derive pulses for implementing the four-qubit version of Shor's algorithm in a single step. Accuracy of the qubit-state transformations, reached in the numerical simulations, is around 0.999. Very detailed insight is obtained by analysis of the time-evolution of state populations and by spectral analysis of the optimized pulse. [ABSTRACT FROM AUTHOR]

We study Markovian stochastic motion on a graph with finite number of nodes and adiabatically periodically driven transition rates. We show that, under general conditions, the quantized currents that appear at low temperatures are a manifestation of topological invariants in the counting statistics of currents. This observation provides an approach for classification of topological properties of the counting statistics, as well as for extensions of the phenomenon of the robust quantization of currents at low temperatures to the properties of the counting statistics which persist to finite temperatures. [ABSTRACT FROM AUTHOR]

This article studies Markovian stochastic motion of a particle on a graph with finite number of nodes and periodically time-dependent transition rates that satisfy the detailed balance condition at any time. We show that under general conditions, the currents in the system on average become quantized or fractionally quantized for adiabatic driving at sufficiently low temperature. We develop the quantitative theory of this quantization and interpret it in terms of topological invariants. By implementing the celebrated Kirchhoff theorem we derive a general and explicit formula for the average generated current that plays a role of an efficient tool for treating the current quantization effects. [ABSTRACT FROM AUTHOR]

Shot noise, which accompanies the emergence of the quantization nature (discreteness) of electrons, indicates dynamic fluctuations in electrical current and further reveals underlying operations in mesoscopic applications. This work presents a multichannel junction device with which to study the shot noise of coupled-channel transports as in normal nanocircuits, and it describes the theoretical algorithms. The numerical results show that, in contrast to the indistinguishable results of average current on direct-current measurements, the shot noise related to a dynamic current definitely exhibits significant differences among devices with diverse multichannel set-ups and presents super-Poissonian behaviors associated with the splitting of tunneling states. [ABSTRACT FROM AUTHOR]

We experimentally demonstrated 16384-ary quadrature amplitude modulation (16384QAM) mobile fronthaul based on 3-amplitude quantization high-pass Delta-sigma Modulation (DSM) in the O band intensity-modulated direct detection (IM/DD) system. By using 3-amplitude quantized high-pass DSM, we successfully quantize the analog waveform of intermediate frequency (IF) Orthogonal Frequency Division Multiplexing (OFDM) signal into 3-Level Pulse Amplitude Modulation (PAM3) signal, and 1 GHz bandwidth 16384-QAM and 1024QAM are successful transmission in 20Gb/s IM/DD link. 0.63% Error Vector Magnitude (EVM) of 16384QAM and 0.7% EVM of 2048QAM are achieved after 25km SSMF and 50km SSMF transmission, respectively. The signal-to-noise ratio (SNR) of the retrieved OFDM signal is 43 dB, which shows that the proposed scheme can support 16384QAM mobile fronthaul network. [ABSTRACT FROM AUTHOR]

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Since the discovery of antimatter it has only been- treated at the level of second quantization, where as, matter is treated at all levels of study, from Newtonian mechanics to quantum field theory. To resolve this scientific imbalance of 20th century, Santilli in 1993 [1],[2],[3] took up to study antimatter at all levels. In this paper we present the classical representation of antimatter at Newtonian level and emerging images at subsequent levels. The most appropriate theory of antimatter as proposed by Santilli [4] is based on a new map called isoduality which is applicable at the Newtonian level and all the subsequent levels of study of antimatter. Santilli also formulated the new anti-isomorphic isodual images of the Galilean, special and general relativities compatible with the experimental knowledge on electromagnetic interactions. Antigravity for antimatter [6] (and vice versa) is a natural consequence of this study and awaits validity due to lack of sufficient experimental evidence. [ABSTRACT FROM AUTHOR]

We study some analytical and geometric properties of a two-dimensional nonlinear sigma model with gravitino which comes from super-symmetric string theory. When the action is critical w.r.t. variations of the various fields including the gravitino, there is a symmetric, traceless, and divergence-free energy-momentum tensor, which gives rise to a holomorphic quadratic differential. Using it we obtain a Pohozaev type identity and finally we can establish the energy identities along a weakly convergent sequence of fields with uniformly bounded energies. [ABSTRACT FROM AUTHOR]

In this paper, we describe ac and dc quantum Hall effect measurements at temperatures above 1.5 K, which is beyond the commonly used value for high precision measurements of the quantum Hall resistance (QHR). It is shown that GaAs devices with high electron density of about $5\times 10^{11}$ cm2 can be used as reliable dc resistance quantum standards with quantization of $R_{\mathrm {H}}$ (2) value with accuracy within a few parts in 109 even at temperatures up to 4.2 K. The devices have exhibited well-developed quantum Hall plateaus in the ac regime too, again at temperatures up to 4.2 K. The measurement system consists of a self-made cryogenic probe with TO-8 type socket together with coaxial wiring and a digitally assisted bridge suitable for ac quantum Hall effect measurements. The experiments were performed with devices placed in new double-shielded TO-8 holders. Our investigations and the evaluation of the measurement system are dedicated for the future realization of the quantum impedance standard based on ac QHR. [ABSTRACT FROM AUTHOR]

A 2n-dimensional Poisson manifold (M ,Π) is said to be bm-symplectic if it is symplectic on the complement of a hypersurface Z and has a simple Darboux canonical form at points of Z which we will describe below. In this article, we will discuss a desingularization procedure which, for m even, converts Π into a family of symplectic forms ωε having the property that ωε is equal to the bm-symplectic form dual to Π outside an ε-neighborhood of Z and, in addition, converges to this form as ε tends to zero in a sense that will be made precise in the theorem below. We will then use this construction to show that a number of somewhat mysterious properties of bm-manifolds can be more clearly understood by viewing them as limits of analogous properties of the ωε's. We will also prove versions of these results for m odd; however, in the odd case the family ωε has to be replaced by a family of "folded" symplectic forms. [ABSTRACT FROM AUTHOR]

This study investigates the quantised-input FIR (finite impulse response) system identification under quantised and event-triggered output observations. For the binary-valued quantisation, they introduce a so-called either-or communication scheme to save communication resources. Based on the received data and the triggered indicator, an identification algorithm is proposed to estimate the unknown parameter by use of the empirical measure and weighted least squares. The convergence performance is established and the communication rate is derived. For the multi-threshold quantisation, it can be seen as a vector-valued observation in which each component represents a binary-valued output, and the corresponding identification problem is discussed. A numerical example is included to illustrate the main results obtained. [ABSTRACT FROM AUTHOR]

Highlights • A very first real application of RS on vibration to evaluate its potential in machine monitoring. • A simulation study to evaluate the effect of RS parameters within its different modes. • An enhanced method for spectral analysis of RS signals based on zero insertion and Welch periodogram. Abstract Random sampling was first introduced in the 1960's (Beutler and Leneman, 1966 [1]), and was then reused in the Compressive Sensing theory (published in 2006 (Donoho, 2006 [2])) for having two important advantages: anti-aliasing property and low sampling rate. These advantages decrease the demand of high speed acquisition and big data storage. In this paper, a brief review of the principal random sampling modes is presented: Additive Random Sampling (ARS) and Jittered Random Sampling (JRS) that both use probability distributions: uniform or Gaussian (Wojtiuk, 2000; Ben Romdhane, 2009; Luo, 2012; Lo and Purvis, 1997 [3–6]). In fact, the stationarity of the random point process is the essential criterion to guarantee the anti-aliasing property (Bilinksis and Mikelson, 1992 [7]). Accordingly, these modes of sampling are studied and used in simulation and hardware implementation. In addition, a study of the time quantization effect is done to explore the different aspects of discrete random sampling (Ben Romdhane, 2009; Luo, 2012 [4,5]). The performance of this sampling is approved by simulation and practice, using respectively Matlab and Arduino microcontroller, respectively, for acquiring signals at a randomly spaced clock. A database was created in order to observe the impact of statistical parameters such as the mean and the standard deviation for Gaussian distribution, and the interval endpoints of uniform distribution. In conclusion, the ARS with uniform distribution has been proved to have less limitations (Ben Romdhane, 2009 [4]), whereas the spectrum of sampled signal is free of alias and the sampling frequency is reduced (a much smaller than Nyquist-Shannon sampling rate). In order to take advantage of this mode, it is applied on vibration signals to enhance remoted machine monitoring. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the robust H ∞ filtering of polytopic uncertain stochastic systems is designed under quantized sampled outputs. An novel parameters-dependent time-scheduled Lyapunov functional is constructed using segmentation technology and linear interpolation. Based on this new Lyapunov functional and convex combination method, sufficient stochastic exponential stability criteria of the filtering error dynamics are proposed and a prescribed H ∞ performance level can be guaranteed by designing the stochastically stable filter. The better H ∞ performance can be obtained with a larger interval dividing parameter. A numerical example is provided to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Effective indexing is a crucial need for large scale object matching and retrieval. In this work, a novel indexing scheme is presented, that exploits the advantages of hierarchical clustering and product quantization. First, the high dimensional feature space is decomposed into disjointed sub-spaces and the data belonging to each sub-space is separately represented by a hierarchical clustering tree. Second, each tree quantizes a distinct part of an input vector to the closest centroid of a leaf node and the distances for all the pairs of centroids are pre-computed and stored in a lookup table. Finally, searching for a given query is proceeded in parallel between the trees and is performed efficiently in the quantized space using the pre-computed lookup tables. The proposed method has been validated by a number of experiments, demonstrating significant improvements of search performance in comparison with other methods. [ABSTRACT FROM AUTHOR]

To locate the tampered region of double compressed JPEG images, one of the most effective methods is based on the statistical characteristic of the images. After tampering operation, the tampered region and the original region will have different statistical distributions. And according to this cue, the histogram of DCT coefficients can be moded as the mixture of the distributions of DCT coefficients in tampered and untampered regions. By estimating each distribution of the mixture model, the probability of being tampered of each DCT block can be calculated and the final localization result can be obtained. Thus the mixture model will significant impact the result. In this paper, a novel mixture model based on normalized gray level co-occurrence matrix (NGLCM) is proposed for tampering localization in JPEG images. Firstly, NGLCM is used to measure the conditional probabilities of being tampered regions and being untampered regions for each 8 × 8 DCT coefficient block, which can take advantage of both the statistical characteristic of double quantization effect and the relationship among neighboring blocks. Then the Bayesian posterior probability map is generated by the conditional probabilities, which indicates the tampering probability of each block. Finally, the map is refined based on a inter-block connectivity and Gaussian weighted filter strategy to determine the final tampered region location. Experimental results demonstrate that the proposed approach can localize the tampered region of JPEG images with a satisfactory performance and outperforms the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Abstract We explain how stochastic TQFT supersymmetry can be made compatible with space supersymmetry. Taking the case of N = 2 supersymmetric quantum mechanics, (the proof would be the same for the Wess–Zumino model), we determine the kernels that ensure the convergence of the stochastic process toward the standard path integral, under the condition that they are covariant under supersymmetry. They depend on a massive parameter M that can be chosen at will and modifies the course of the stochastic evolution, but the infinite stochastic time limit of the correlation functions is in fact independent on the choice of M. [ABSTRACT FROM AUTHOR]

A new quantizing technology scheme of insulator soldering was presented comparing with traditional soldering technology using solder paste, based on utilization of solid solder ring and the consideration of insulator mounting hole design on the microwave module shell. The X‐ray test on void ratio of insulator soldering shows that there exists no penetration void and the void ratio is below 5%. According to the leak standard A4 of GJB 548B‐1014.2, the standard leak rate of microwave module after the insulator soldering was below 5 × 10−9(Pa·m3)/s. After 10 cycles of temperature shock test ranging from −55°C to 125°C, the standard leak rate of microwave module was still below 5 × 10−9 (Pa·m3)/s. In comparison with traditional insulator soldering technology using solder paste, through utilization of solid solder ring and the design of insulator mounting hole, this new technology quantized the soldering of insulator so as to resolve the existing defects of traditional insulator soldering such as solder overflow, high void ratio, shortcut and channel blocking. The quantized insulator sealed soldering technology ensured the reliability, air impermeability, uniformity and beautifulness of soldering meanwhile improved operators' efficiency. [ABSTRACT FROM AUTHOR]

In this paper, we propose two non-uniform quantization (NUQ) codebook-based hybrid precoding schemes for two main hybrid precoding implementations, i.e., the full-connected structure and the sub-connected structure, to reduce the feedback overhead in millimeter wave single user multiple-input multiple-output systems. Specifically, we firstly group the angles of the arrive/departures (AOAs/AODs) of the scattering paths into several spatial lobes by exploiting the sparseness property of the millimeter wave in the angular domain, which divides the total angular domain into effective spatial lobes’ coverage angles and ineffective coverage angles. Then, we map the quantization bits non-uniformly to different coverage angles and construct NUQ codebooks, where high numbers of quantization bits are employed for the effective coverage angles to quantize AoAs/AoDs and zero quantization bit is employed for ineffective coverage angles. Finally, two low-complexity hybrid analog/digital precoding schemes are proposed, which utilize the NUQ codebooks. Simulation results demonstrate that the proposed two NUQ codebook-based hybrid precoding schemes achieve near-optimal spectral efficiencies and show the superiority in reducing the feedback overhead compared with the uniform quantization codebook-based works. [ABSTRACT FROM AUTHOR]

Quantization or pseudodi-erential analysis is a theory which applies to numerous domains (functional analysis, operator theory, mathematical physics etc.) The classical framework is that of finite dimensional configuration and phase spaces. To handle problems involving an arbitrary number of particles, one needs to work with operators defined on infinite dimensional spaces, like the symmetric Fock space, and one may wish to use the efficient tools provided by the Weyl calculus, hence to work with an infinite dimensional measure space. This survey exposes the construction of a quantization on an abstract Wiener space, lists the results of pseudodifferential analysis which were generalized and gives applications to mathematical physics. [ABSTRACT FROM AUTHOR]

This paper proposes a novel robust image watermarking scheme in Discrete Cosine Transform (DCT) domain for active forensics. We investigate the relation between the positions and the modification magnitudes of DCT coefficients and directions of texture blocks. By exploring such relation, a direction-coefficient mapping is designed. First, the texture direction of each image block is estimated by Gabor filter. And then, according to the direction-coefficient mapping, one watermark bit is embedded into each block along its texture direction. Compared with existing schemes, the proposed method utilizes the direction features of texture blocks better. Therefore, the improvements in watermarked image quality and the robustness of watermark signal against image processing attacks are both achieved. [ABSTRACT FROM AUTHOR]

Recently, the methods of quantum theory, especially quantum information, started to be widely applied outside of physics: in cognitive, social sciences, economics, finance, decision making and biology. We propose a quantum-like model: the "information laser". The basic assumption is the discrete structure of state spaces related to the quantization of information. The information field acts in the form of indistinguishable quanta of "social energy" analogue to photons. The massive flow of information acts as a laser pump. In this framework, an information selection process by agents under constant pressure of massive repeated information leads to collective "resonance" effects in analogy with laser cavity and stimulated emission. In order to make operational parallels between physical lasers and the information laser we identify the essential features of laser operation. An application to the analysis of recent disruptive social events (colour revolutions) is discussed. Social analogues to the laser are also considered through the model of Echo Chambers induced by the Internet and Adam Smith's invisible hand. [ABSTRACT FROM AUTHOR]

Abstract Recently, we have used a projection operator to fix the number of particles in a second quantization approach in order to deal with the canonical ensemble. Having been applied earlier to handle various problems in nuclear physics that involve fixed particle numbers, the projector formalism was extended to grant access as well to quantum-statistical averages in condensed matter physics, such as particle densities and correlation functions. In this light, the occupation numbers of the subsequent single-particle energy eigenstates are key quantities to be examined. The goal of this paper is (1) to provide a sound extension of the projector formalism directly addressing the occupation numbers as well as the chemical potential, and (2) to demonstrate how the emerging problems related to numerical instability for fermions can be resolved to obtain the canonical statistical quantities for both fermions and bosons. Highlights • Quantum canonical ensemble. • Bosons and fermions. • Projection operator. • Fock space. • Free energy, chemical potential, occupation numbers. [ABSTRACT FROM AUTHOR]

Inverted indexing based on vector quantization has been a popular technique in large scale information retrieval. With vector quantization based on a certain similarity metric, the sample space is partitioned into some voronoi cells, and samples in each cell are indexed by an inverted list. The nearest neighbors of a query are efficiently identified by looking up the cell where the query is located. To improve the recall, the sample space partitioning has been performed multiple times with different initializations of k-means to build multiple inverted indexes. While with the single similarity metric, e.g., Euclidean distance, high correlation may exist between multiple inverted indexes, which constrains the possible gain in recall. A new multiple inverted indexing method based on multiple sample space partitioning with multiple different similarity metrics is presented in this paper. Furthermore, several techniques for defining multiple metrics are investigated empirically. Experiments are conducted on 3 representative datasets, million-scale SIFT and GIST feature sets and a deep-learning-produced feature set, to properly evaluate the effectiveness of the proposed method. Experiment results show that the proposed method has competitive performance compared with the state-of-the-art inverted indexing methods in terms of recall and retrieval time, and the Latin-Hypercube weighting method can generate better diverse multiple metrics and get better gain in recall. [ABSTRACT FROM AUTHOR]