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We examined a one-dimensional quantum Heisenberg model that includes trimer-like correlated disordered exchange couplings and a non-uniform magnetic field. We conducted numerical experiments to study the transfer of magnons between the two ends of the chain. Using numerical methods, we calculated the time evolution of a localized magnon state at the left end of the chain. We evaluated the quality of the transfer from the left end to the right using standard tools such as fidelity and concurrence. Our calculations demonstrate the existence of magnon transfer with good fidelity for some specific energies ( E > 0 ) in the absence of a magnetic field. We also investigated the impact of the random magnetic field on our findings. [ABSTRACT FROM AUTHOR]

We investigate in detail the transference of quantum states in a disordered channel. We consider a one-dimensional tight-binding model consisting of a source S connected to a receiver R throughout a disordered channel. The disorder distribution contains a single tunable spatial correlation length. We demonstrate that the disorder correlation length plays a relevant role within the localization properties of the channel. The hopping parameter between the sites S and R and the channel are also adjustable parameters. We investigate the possibility of transference of quantum states along this quantum channel model and describe the optimal conditions for the occurrence of a high fidelity process. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the one-electron propagation in a nonlinear chain with electron–lattice interaction. The model contains standard cubic nonlinear terms, and we introduce the coupling between the electron and the lattice through the hopping distribution. We solve the coupled equation set to electron and lattice and calculate the electronic position as a function of time. We provide a detailed investigation of the electron and lattice dynamics for a wide range of electron–lattice coupling intensities. Our results demonstrate that depending on the initial condition we consider and the intensity of the electron–lattice interaction, we can obtain (or not) an electron–phonon pair formation. Our results reveal that, depending on the initial velocity of the lattice and the degree of electron–lattice term, we can observe a repulsion between electron and lattice deformations. [ABSTRACT FROM AUTHOR]

The transmission of a qubit in a tight-binding channel with exponentially decaying hopping terms and diagonal disorder is investigated. The end sites act as sender and receiver and are perturbatively coupled to the channel. This is done to suppress interference of the channel modes during the time evolution of the state. We explore the performance of the transfer fidelity against the disorder strength and hopping range within the channel. The scaling behavior of the participation number as a function of the hopping range is also discussed. Channels featuring long-range interactions display distinct robustness against disorder and high-quality quantum state transfer is attainable even for disorder levels of the order of the largest hopping amplitude. [ABSTRACT FROM AUTHOR]

In this paper, we consider a square lattice with correlated random hopping terms under the effect of an external electric field. We analyzed the dynamics of an initially localized electronic wave packet using a Taylor formalism to solve the Schrödinger dynamic equation. Our calculations suggest that the correlated disorder promotes a fast electronic propagation for intermediate times. When we switch on a static electric field, we observe an oscillatory behavior similar to the well-known "Bloch oscillations" phenomenology. We calculate the frequency of these oscillations, and our results are in good agreement with those predicted by the semi-classical approach used in crystalline lattices. Based on the local disorder and in the absence of extended states in our model, we discussed the stability of these apparent "Bloch oscillations". [ABSTRACT FROM AUTHOR]

We investigate a quantum-state transfer protocol through a quasi-1D spin-1/2 channel defined on a hexagonal layer featuring hopping disorder. In the absence of disorder, the quantum channel displays two flat bands hosting compact localized states. That is signalled by the appearance of singularities in the density of states. We show that an arbitrary qubit state can be transmitted with high fidelity between the two ends even in the presence of noise as long as they are not in resonance with energy levels surrounding the flat band. This higher sensitivity against disorder is due to the residual single-cell compact localized states accompanied by a degeneracy lifting. [ABSTRACT FROM AUTHOR]

We investigate the spreading of SARS-CoV-2 in the state of Alagoas, northeast of Brazil, via an adaptive susceptible-infected-removed (SIR) model featuring dynamic recuperation and propagation rates. Input parameters are defined based on data made available by Alagoas Secretary of Health from April 19, 2020 on. We provide with the evolution of the basic reproduction number R 0 and reproduce the historical series of the number of confirmed cases with less than 1 0 % error. We offer predictions, from November 16 forward, over the epidemic situation in the near future and show that it will keep decelerating. Furthermore, the same model can be used to study the epidemic dynamics in other countries with great easiness and accuracy. [ABSTRACT FROM AUTHOR]

In this work, we consider a one-electron moving on a Fermi, Pasta, Ulam disordered chain under effect of electron-phonon interaction and a Gaussian acoustic pulse pumping. We describe electronic dynamics using quantum mechanics formalism and the nonlinear atomic vibrations using standard classical physics. Solving numerical equations related to coupled quantum/classical behavior of this system, we study electronic propagation properties. Our calculations suggest that the acoustic pumping associated with the electron-lattice interaction promote a sub-diffusive electronic dynamics. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influence of electron-lattice interaction on the stability of uniform electronic wavepackets on chains as well as on several types of fullerenes. We will use an effective nonlinear Schrödinger equation to mimic the electron-phonon coupling in these topologies. By numerically solving the nonlinear dynamic equation for an initially uniform electronic wavepacket, we show that the critical nonlinear coupling above which it becomes unstable continuously decreases with the chain size. On the other hand, the critical nonlinear strength saturates on a finite value in large fullerene buckyballs. We also provide analytical arguments to support these findings based on a modulational instability analysis. [ABSTRACT FROM AUTHOR]

We investigate the electronic transport properties of methylated deoxyribonucleic-acid (DNA) strands, a biological system in which methyl groups are added to DNA (a major epigenetic modification in gene expression), sandwiched between two metallic platinum electrodes. Our theoretical simulations apply an effective Hamiltonian based on a tight-binding model to obtain current-voltage curves related to the non-methylated/methylated DNA strands. The results suggest potential applications in the development of novel biosensors for molecular diagnostics. [ABSTRACT FROM AUTHOR]

We address the question regarding the effect of correlated random spring constants in the one-dimensional harmonic model. We consider all masses to be equal but the spring constants given by a random sequence with long-range correlations. We generate the long-range correlated sequence of spring constants by using a fractional Brownian motion with a power-law spectral density S(κ) = 1/κα. Using an exact diagonalization formalism, we compute the participation moments of eigenmodes within the band of allowed frequencies. We unveil a regime on which all modes below a critical frequency become extended. [ABSTRACT FROM AUTHOR]

In this paper, we study the dynamics of a one-electron in a one-dimensional (1d) alloy with a correlated Ornstein-Uhlenbeck (OU) disorder distribution. The model considered here corresponds to an alloy with three types of atoms where the position of each atom is obtained using a stochastic rule based on the OU process. We analyze in detail the effect of this correlated disorder in the optical absorption spectrum and the level spacing statistics near the band center. Our results reveal a new collection of optical absorption peaks. We explain in details the appearance of each peak. Our calculations about the level spacing's distribution reveals a Poisson distribution thus contradicting previous statements about the existence of extended states in ternary electronic models with correlated disorder distribution. [ABSTRACT FROM AUTHOR]

We study the nature of collective excitations in classical anharmonic lattices with aperiodic and pseudo-random harmonic spring constants. The aperiodicity was introduced in the harmonic potential by using a sinusoidal function whose phase varies as a power-law, ϕ ∝ nν, where n labels the positions along the chain. In the absence of anharmonicity, we numerically demonstrate the existence of extended states and energy propagation for a sufficiently large degree of aperiodicity. Calculations were done by using the transfer matrix formalism (TMF), exact diagonalization and numerical solution of the Hamilton's equations. When nonlinearity is switched on, we numerically obtain a rich framework involving stable and unstable solitons. [ABSTRACT FROM AUTHOR]

In this paper we study the propagation of acoustic waves in a one-dimensional system with nonstationary chaotic elasticity distribution. The elasticity distribution is assumed to have a power spectrum S(f) ~ 1/f(2B-3)/(B-1) for B ≥ 1.5. By using a transfer-matrix method we solve the discrete version of the scalar wave equation and compute the Lyapunov exponent. In addition, we apply a second-order finite-difference method for both the time and spatial variables and study the nature of the waves that propagate in the chain. Our numerical data indicate the presence of weak localized acoustic waves for high degree of correlations (B > 2). [ABSTRACT FROM AUTHOR]

We numerically study the propagation of acoustic waves in a one-dimensional system with an aperiodic pseudo-random elasticity distribution. The elasticity distribution was generated by using a sinusoidal function whose phase varies as a power-law, $\phi \propto n^{\nu}$, where n labels the positions along the media. By considering a discrete one-dimensional version of the wave equation and a matrix recursive reformulation we compute the localization length within the band of allowed frequencies. In addition, we apply a second-order finite-difference method for both the time and spatial variables and study the nature of the waves that propagate in the chain. Our numerical data indicates the presence of extended acoustic waves with non-zero frequency for sufficient degree of aperiodicity. [ABSTRACT FROM AUTHOR]

In this paper, we consider the effect of an aperiodic hopping distribution on a single electron. The aperiodic sequence of hopping energies was generated by using a sinusoidal function whose phase ϕ varies as a power-law, ϕ ∝ nν, where n labels the positions along the chain. The exponent ν controls the degree of aperiodicity in the sequence hopping terms. Using the transfer matrix method, we compute the localization length within the band of allowed energies. Our numerical calculations indicate that, for an aperiodic sequence of hopping energies with ν < 1, a new phase of extended states appears in this model. For a pseudorandom hopping distribution with ν > 1, all eigenstates remain localized. In addition, we study the electronic dynamics subjected to an electric field. Our numerical calculations reveals perfect Bloch oscillations for ν < 1. The typical frequency of these oscillations agree with the semiclassical predictions. [ABSTRACT FROM AUTHOR]

We study the nature of the vibrational modes in a two-dimensional harmonic lattice with long-range correlated random masses, with power-law spectral density S(k)∼1/kα. We obtain numerically the scale invariance of the fluctuations of the relative participation number and the local density of states. We find signatures of extended vibrational modes when α>αc and αc depends on the magnitude of disorder. In order to confirm this claim, we also study the time evolution of an initially localized perturbation of the lattice. We show that the second moment of the spatial distribution of the energy displays a ballistic regime when α>αc, in agreement with the occurrence of extended vibrational modes. [ABSTRACT FROM AUTHOR]

In this work, a one-dimensional quantum Heisenberg ferromagnet with aperiodic exchange couplings is considered. To produce an aperiodic distribution of exchange couplings, it is used a sinusoidal function whose phase φ varies as a power-law, φ∝nν, where n labels the positions along the chain. By using exact diagonalization, the spin-wave participation number and the local density of states are computed. The numerical calculations indicate that for 0 < ν < 1, this ferromagnetic system displays a phase of extended spin waves in the low-energy region. For ν > 1 all spin waves are localized except for the zero energy mode. By integrating the time-dependent Schrödinger equation, the temporal evolution of the mean-square displacement of the wave-packet was followed. Associated with the emergence of extended spin waves, it was observed that the wave-packet mean-square displacement displays a ballistic spread. [ABSTRACT FROM AUTHOR]

We study the nature of one-electron eigen-states in a one-dimensional diluted Anderson model where every Anderson impurity is diluted by a periodic function f(l). Using renormalization group and transfer matrix techniques, we provide accurate estimates of the extended states which appear in this model, whose number depends on the symmetry of the diluting function f(l). The density of states (DOS) for this model is also numerically obtained and its main features are related to the symmetries of the diluting function f(l). Further, we show that the emergence of extended states promotes a sub-diffusive spread of an initially localized wave-packet. [ABSTRACT FROM AUTHOR]

The goal of this study was to evaluate the effects of supplementation frequency during pre (105 d from parturition) and postpartum (105 d from parturition) of Nellore primiparous cows on performance and physiological responses. Twenty-five pregnant heifers with an average BW of 408 ± 2 kg and 172 ± 2 d of gestation were used in this trial. Animals were housed in 6 paddocks with full access to water, and stocking rate was defined on the basis of potentially digestible DM availability (DMpd). Evaluated treatments were: control (ad libitum mineral mix); daily supplementation (1.5 kg of concentrate/animal); and supplementation every 3 d (4.5 kg of concentrate/animal). Two 9-d digestibility trials were performed at 55 d before parturition and 55 d after parturition. Plasma concentrations of glucose, IGF-1, NEFA, and beta-hydroxybutyrate (BHB) were used as indicators of energy state and collected at 27 and 9 d before parturition, on the day of parturition, and 9 and 27 d after parturition. The response variables were analyzed using PROC MIXED in SAS 9.4 (SAS Inst., Cary, NC) assuming a completely randomized design with 3 treatments and 2 replicates per treatments. Treatment was considered a fixed effect whereas treatment within paddock was considered random. The DMpd observed during the experiment for pre and postpartum was 4.4 t/ha and 2.9 t/ha, respectively, which corresponded to the momentary mean availability of 78.6 and 52.9 g/kg BW. The DMI was not affected by supplementation frequency during peripartum (P > 0.10) or postpartum (P > 0.10). The supplementation frequency did not affect BW at 10 d before parturition (P > 0.10) or at 105 d after parturition (P > 0.10). Glucose concentration was affected by supplementation frequency (72.27 vs. 65.62 mg/dL for pre and postpartum respectively; P < 0.10). Most likely, daily supplementation reduces oscillation and increases circulating concentrations of glucose. Circulating concentrations of IGF-1 (206 vs. 222 vs. 201 ng/mL for pre and postpartum respectively; P > 0.10), NEFA (0.21 vs. 0.23 vs. 0.18 mmol/L for pre and postpartum respectively; P > 0.10), and BHB (0.45 vs. 0.52 vs. 0.45 mmol/L for pre and postpartum respectively; P > 0.10) did not differ among treatments. The forage availability associated with lack of supplementation frequency effect on intake may have contributed to no changes in performance and physiological responses. These results suggest that when there is non-restriction on forage availability, supplementation frequency during pre and postpartum does not affect performance or physiological responses of primiparous Nellore cows. [ABSTRACT FROM AUTHOR]