Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Relaxation to Equilibrium for Two Dimensional Disordered Ising Systems in the Griffiths Phase (1997)
    Springer
    Communications in mathematical physics 189 (1997), S. 323-335 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract: We consider Glauber–type dynamics for two dimensional disordered magnets of Ising type. We prove that, if the disorder–averaged influence of the boundary condition is sufficiently small in the equilibrium system, then the corresponding Glauber dynamics is ergodic with probability one and the disorder–average C(t) of time–autocorrelation function satisfies (for large t). For the standard two dimensional dilute Ising ferromagnet with i.i.d. random nearest neighbor couplings taking the values 0 or J 0〉0, our results apply even if the active bonds percolate and J 0 is larger than the critical value J c of the corresponding pure Ising model. For the same model we also prove that in the whole Griffiths' phase the previous upper bound is optimal. This implies the existence of a dynamical phase transition which occurs when J crosses J c .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002200050205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The Spectral Gap for the Kawasaki Dynamics at Low Temperature (1999)
    Springer
    Journal of statistical physics 95 (1999), S. 215-271 
    Details
    ISSN: 1572-9613
    Keywords: Kawasaki dynamics ; spectral gap ; large deviations ; Wulff construction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper we analyze the convergence to equilibrium of Kawasaki dynamics for the Ising model in the phase coexistence region. First we show, in strict analogy with the nonconservative case, that in any lattice dimension, for any boundary condition and any positive temperature and particle density, the spectral gap in a box of side L does not shrink faster than a negative exponential of the surface L d−1. Then we prove that, in two dimensions and for free boundary condition, the spectral gap in a box of side L is smaller than a negative exponential of L provided that the temperature is below the critical one and the particle density ρ satisfies ρ∈(ρ*−, ρ*+), where ρ*± represents the particle density of the plus and minus phase, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004581512343
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Instability of renormalization-group pathologies under decimation (1995)
    Springer
    Journal of statistical physics 79 (1995), S. 25-42 
    Details
    ISSN: 1572-9613
    Keywords: Renormalization group ; decimation ; non-Gibbsianness ; Ising model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the stability and instability of pathologies of renormalization group transformations for lattice spin systems under decimation. In particular we show that, even if the original renormalization group transformation gives rise to a non-Gibbsian measure, Gibbsianness may be restored by applying an extra decimation transformation. This fact is illustrated in detail for the block spin transformation applied to the Ising model. We also discuss the case of another non-Gibbsian measure with nicely decaying correlations functions which remains non-Gibbsian after arbitrary decimation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02179382
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Convergence to Equilibrium of Random Ising Models in the Griffiths Phase (1998)
    Springer
    Journal of statistical physics 92 (1998), S. 337-351 
    Details
    ISSN: 1572-9613
    Keywords: Random spin systems ; diluted Ising model ; Glauber dynamics ; relaxation time ; Griffiths singularities ; FK representation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We consider Glauber-type dynamics for disordered Ising spin systems with nearest neighbor pair interactions in the Griffiths phase. We prove that in a nontrivial portion of the Griffiths phase the system has exponentially decaying correlations of distant functions with probability exponentially close to 1. This condition has, in turn, been shown elsewhere to imply that the convergence to equilibrium is faster than any stretched exponential, and that the average over the disorder of the time-autocorrelation function goes to equilibrium faster than exp[−k(log t) d/(d−1)]. We then show that for the diluted Ising model these upper bounds are optimal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1023077101354
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Relaxation of Disordered Magnets in the Griffiths' Regime (1997)
    Springer
    Communications in mathematical physics 188 (1997), S. 135-173 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract: We study the relaxation to equilibrium of discrete spin systems with random finite range (not necessarily ferromagnetic) interactions in the Griffiths' regime. We prove that the speed of convergence to the unique reversible Gibbs measure is almost surely faster than any stretched exponential, at least if the probability distribution of the interaction decays faster than exponential (e.g. Gaussian). Furthermore, if the interaction is uniformly bounded, the average over the disorder of the time–autocorrelation function, goes to equilibrium as (in d 〉 1), in agreement with previous results obtained for the dilute Ising model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002200050160
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Detection and identification ofMycobacterium avium in the blood of AIDS patients by the polymerase chain reaction (1996)
    Springer
    European journal of clinical microbiology & infectious diseases 15 (1996), S. 551-555 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract One hundred fifty-three blood samples from patients positive for the human immunodeficiency virus (HIV) were analyzed by polymerase chain reaction (PCR) to detect the presence ofMycobacterium avium. Samples were collected from patients who also had blood cultures performed by a radiometric method. Blood samples were centrifuged on a Ficoll-Hypaque gradient to purify peripheral blood mononuclear cells. The purified cells were washed and incubated with a resin, boiled to release mycobacterial DNA, and then amplified. Polymerase chain reaction products were detected by a nonisotopic method. A 123 base-pair (bp) insertion sequence, namely IS6110, fromMycobacterium tuberculosis complex was also included in the reaction as an internal control ofTaq polymerase activity to exclude the presence of enzyme inhibitors. This IS6110 fragment can be distinguished from the 383 bp target product on ethidium bromide-stained agarose gel and may also be used in a colorimetric assay. Such results were compared with the results of culture and indicated that the assay is as sensitive as bacteriological methods, though faster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01709362
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    On the two-dimensional stochastic Ising model in the phase coexistence region near the critical point (1996)
    Springer
    Journal of statistical physics 85 (1996), S. 55-102 
    Details
    ISSN: 1572-9613
    Keywords: Stochastic Ising model ; phase coexistence ; relaxation time ; spectral gap ; surface tension ; large deviations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We consider the two-dimensional stochastic Ising model in finite square Λ with free boundary conditions, at inverse temperature β〉β0 and zero external field. Using duality and recent results of Ioffe on the Wulff construction close to the critical temperature, we extend some of the results obtained by Martinelli in the low-temperature regime to any temperature below the critical one. In particular we show that the gap in the spectrum of the generator of the dynamics goes to zero in the thermodynamic limit as an exponential of the side length of Λ, with a rate constant determined by the surface tension along one of the coordinate axes. We also extend to the same range of temperatures the result due to Shlosman on the equilibrium large deviations of the magnetization with free boundary conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02175556
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Stochastic Comparison Algorithm for Discrete Optimization with Estimation of Time-Varying Objective Functions (1999)
    Springer
    Journal of optimization theory and applications 103 (1999), S. 137-159 
    Details
    ISSN: 1573-2878
    Keywords: Stochastic optimization ; simulation ; estimation ; time-varying objective functions ; discrete event dynamic systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract In this paper, the optimization of time-varying objective functions, known only through estimates, is considered. Recent research defined algorithms for static optimization problems. Based on one of these algorithms, we derive an optimization scheme for the time-varying case. In stochastic optimization problems, convergence of an algorithm to the optimum prevents the algorithm from being efficiently adaptive to changes of the objective function if it is time-varying. So, convergence cannot be required in a time-varying scenario. Rather, we require convergence to the optimum with high probability together with a satisfactory dynamical behavior. Analytical and simulative results illustrate the performance of the proposed algorithm compared with other optimization techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021777501274
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...