Exact Occupation Time Distribution in a Non-Markovian Sequence and Its Relation to Spin Glass Models

We compute exactly the distribution of the occupation time in a discrete {\em non-Markovian} toy sequence which appears in various physical contexts such as the diffusion processes and Ising spin glass chains. The non-Markovian property makes the results nontrivial even for this toy sequence. The distribution is shown to have non-Gaussian tails characterized by a nontrivial large deviation function which is computed explicitly. An exact mapping of this sequence to an Ising spin glass chain via a gauge transformation raises an interesting new question for a generic finite sized spin glass model: at a given temperature, what is the distribution (over disorder) of the thermally averaged number of spins that are aligned to their local fields? We show that this distribution remains nontrivial even at infinite temperature and can be computed explicitly in few cases such as in the Sherrington-Kirkpatrick model with Gaussian disorder.Comment: 10 pages Revtex (two-column), 1 eps figure (included

Reliability-based code revision for design of pile foundations: Practice in Shanghai, China

AbstractThis paper describes how the code for the design of pile foundations in Shanghai, China is revised based on the reliability theory. With quality static load test data, both within-site and cross-site variabilities for design methods of piles in Shanghai are characterized. It is found that the amount of uncertainties associated with the design of piles in Shanghai is less than the typical values reported in the literature. With the partial factors specified in the previous design code, the reliability indexes of piles designed with empirical methods are in the range of 3.08–4.64, while those of piles designed with the load test-based method are in the range of 5.67–5.89. The load factors in the revised local design code have been reduced according to the national design code. As a result, the resistance factors have been increased in the revised code based on a combination of a reliability analysis and engineering judgment. In the revised design code, the reliability level of piles designed with the empirical methods is similar to that in the previous design code; the reliability level of piles designed with the load test-based method is lowered to achieve cost-effectiveness. Partial factors have been suggested for side and toe resistances based on the reliability theory considering their relative importance as well as the uncertainties involved

Random Walks in Logarithmic and Power-Law Potentials, Nonuniversal Persistence, and Vortex Dynamics in the Two-Dimensional XY Model

The Langevin equation for a particle (`random walker') moving in d-dimensional space under an attractive central force, and driven by a Gaussian white noise, is considered for the case of a power-law force, F(r) = - Ar^{-sigma}. The `persistence probability', P_0(t), that the particle has not visited the origin up to time t, is calculated. For sigma > 1, the force is asymptotically irrelevant (with respect to the noise), and the asymptotics of P_0(t) are those of a free random walker. For sigma < 1, the noise is (dangerously) irrelevant and the asymptotics of P_0(t) can be extracted from a weak noise limit within a path-integral formalism. For the case sigma=1, corresponding to a logarithmic potential, the noise is exactly marginal. In this case, P_0(t) decays as a power-law, P_0(t) \sim t^{-theta}, with an exponent theta that depends continuously on the ratio of the strength of the potential to the strength of the noise. This case, with d=2, is relevant to the annihilation dynamics of a vortex-antivortex pair in the two-dimensional XY model. Although the noise is multiplicative in the latter case, the relevant Langevin equation can be transformed to the standard form discussed in the first part of the paper. The mean annihilation time for a pair initially separated by r is given by t(r) \sim r^2 ln(r/a) where a is a microscopic cut-off (the vortex core size). Implications for the nonequilibrium critical dynamics of the system are discussed and compared to numerical simulation results.Comment: 10 pages, 1 figur

Can the "brick wall" model present the same results in different coordinate representations?

By using the 't Hooft's "brick wall" model and the Pauli-Villars regularization scheme we calculate the statistical-mechanical entropies arising from the quantum scalar field in different coordinate settings, such as the Painlev\'{e} and Lemaitre coordinates. At first glance, it seems that the entropies would be different from that in the standard Schwarzschild coordinate since the metrics in both the Painlev\'{e} and Lemaitre coordinates do not possess the singularity at the event horizon as that in the Schwarzschild-like coordinate. However, after an exact calculation we find that, up to the subleading correction, the statistical-mechanical entropies in these coordinates are equivalent to that in the Schwarzschild-like coordinate. The result is not only valid for black holes and de Sitter spaces, but also for the case that the quantum field exerts back reaction on the gravitational field provided that the back reaction does not alter the symmetry of the spacetime.Comment: 8 pages, Phys. Rev. D in pres

Charmonium states in QCD-inspired quark potential model using Gaussian expansion method

We investigate the mass spectrum and electromagnetic processes of charmonium system with the nonperturbative treatment for the spin-dependent potentials, comparing the pure scalar and scalar-vector mixing linear confining potentials. It is revealed that the scalar-vector mixing confinement would be important for reproducing the mass spectrum and decay widths, and therein the vector component is predicted to be around 22%. With the state wave functions obtained via the full-potential Hamiltonian, the long-standing discrepancy in M1 radiative transitions of $J/\psi$ and $\psi^{\prime}$ are alleviated spontaneously. This work also intends to provide an inspection and suggestion for the possible $c\bar{c}$ among the copious higher charmonium-like states. Particularly, the newly observed X(4160) and X(4350) are found in the charmonium family mass spectrum as $M(2^1D_2)= 4164.9$ MeV and $M(3^3P_2)= 4352.4$ MeV, which strongly favor the $J^{PC}=2^{-+}, 2^{++}$ assignments respectively. The corresponding radiative transitions, leptonic and two-photon decay widths have been also predicted theoretically for the further experimental search.Comment: 16 pages,3 figure

Running mechanics adjustments to perceptually-regulated interval runs in hypoxia and normoxia

Objectives We determined whether perceptually-regulated, high-intensity intermittent runs in hypoxia and normoxia induce similar running mechanics adjustments within and between intervals. Design Within-participants repeated measures. Methods Nineteen trained runners completed a high-intensity intermittent running protocol (4×4-min intervals at a perceived rating exertion of 16 on the 6–20 Borg scale, 3-min passive recoveries) in either hypoxic (FiO2 =0.15) or normoxic (FiO2 =0.21) conditions. Running mechanics were collected over 10 consecutive steps, at constant velocity (∼15.0±2.0km.h−1), at the beginning and the end of each 4-min interval. Repeated measure ANOVA were used to assess within intervals (onset vs. end of each interval), between intervals (interval 1, 2, 3 vs. 4) and FiO2 (0.15 vs. 0.21) main effects and any potential interaction. Results Participants progressively reduced running velocity from interval 1–4, and more so in hypoxia compared to normoxia for intervals 2, 3 and 4 (P 0.298) and FiO2 (across all intervals P >0.082) main effects or any significant between intervals×within intervals×FiO2 interactions (all P >0.098) for any running mechanics variables. Irrespective of interval number or FiO2, peak loading rate (+10.6±7.7%; P <0.001) and duration of push-off phase (+2.0±3.1%; P =0.001) increased from the onset to the end of 4-min intervals, whereas peak push-off force decreased (−4.0±4.0%; P <0.001). Conclusions When carrying out perceptually-regulated interval treadmill runs, runners adjust to progressively slower velocities in hypoxia compared to normoxia. However, only subtle constant-velocity modifications of their mechanical behaviour occurred within each set, independently of FiO2 or interval number

Evolution of Non-Equilibrium Profile in Adsorbate Layer under Compressive Strain

We investigate the time evolution of an initial step profile separating a bare substrate region from the rest of the compressively strained adsorbate layer near a commensurate to incommensurate transition. The rate of profile evolution as a function of the mismatch, coverage and the strength of the substrate potential are determined by Brownian molecular dynamics simulations. We find that the results are qualitatively similar to those observed for the Pb/Si(111) system. The anomalously fast time evolution and sharpness of the non-equilibrium profile can be understood through the domain wall creation at the boundary and its subsequent diffusion into the interior of the adsorbate layer.Comment: 6 pages, 7 figures, Tribology Letter

Studying Kaon-pion S-wave scattering in K-matrix formalism

We generalize our previous work on \pi\pi scattering to K\pi scattering, and re-analyze the experiment data of K\pi scattering below 1.6 GeV. Without any free parameter, we explain K\pi I=3/2 S-wave phase shift very well by using t-channel rho and u-channel K^* meson exchange. With the t-channel and u-channel meson exchange fixed as the background term, we fit the K\pi I=1/2 S-wave data of the LASS experiment quite well by introducing one or two s-channel resonances. It is found that there is only one s-channel resonance between K\pi threshold and 1.6 GeV, i.e., K_0^*(1430) with a mass around 1438~1486 MeV and a width about 346 MeV, while the t-channel rho exchange gives a pole at (450-480i) MeV for the amplitude.Comment: REVTeX4 file, 11 pages and 3 figure

Delocalization in harmonic chains with long-range correlated random masses

We study the nature of collective excitations in harmonic chains with masses exhibiting long-range correlated disorder with power spectrum proportional to $1/k^{\alpha}$, where $k$ is the wave-vector of the modulations on the random masses landscape. Using a transfer matrix method and exact diagonalization, we compute the localization length and participation ratio of eigenmodes within the band of allowed energies. We find extended vibrational modes in the low-energy region for $\alpha > 1$. In order to study the time evolution of an initially localized energy input, we calculate the second moment $M_2(t)$ of the energy spatial distribution. We show that $M_2(t)$, besides being dependent of the specific initial excitation and exhibiting an anomalous diffusion for weakly correlated disorder, assumes a ballistic spread in the regime $\alpha>1$ due to the presence of extended vibrational modes.Comment: 6 pages, 9 figure

Hot air drying combined vacuum-filling nitrogen drying of apple slices: Drying characteristics and nutrients

[EN] In this paper, hot air drying (HAD) was applied when moisture content of apple slices range from 50% to 86%, and then vacuum-filling nitrogen drying (VFND) was used till moisture content reaching 7%. Results showed that, the drying rate of apple slice during VFND period increased with temperature increment and decreased with increment of slice thickness; compared to freezing dried samples, samples dried in this research were owned lower Vc and higher flavonoid; when HAD (70℃,3.0m/s)+VFND(relative pressure 0.08MPa, 50℃) and thickness of 6.0mm, nutrients reached better levels: retentions of Vc, total phenolics and flavonoid were 1.63mg/100g, 4.07mg/100g and 2.10mg/100g, respectively.The work was financially supported by the Fundamental Research Funds for the Central Universities of China (NO. GK201503072 and GK201601007).Huang, X.; Li, T.; Li, S.; Wu, Z.; Xue, J. (2018). Hot air drying combined vacuum-filling nitrogen drying of apple slices: Drying characteristics and nutrients. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 811-818. https://doi.org/10.4995/IDS2018.2018.7477OCS81181