Statistics of random optical field generated by a random walk with a finite number of steps

2021 ◽  
Author(s):  
Bozhen Zhang ◽  
Xin Liu ◽  
Jun Dai ◽  
Ying Wang ◽  
Wei Wang
2005 ◽  
Vol 42 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Thomas Mountford ◽  
Rinaldo B. Schinazi

We show that a branching random walk that is supercritical on is also supercritical, in a rather strong sense, when restricted to a large enough finite ball of This implies that the critical value of branching random walks on finite balls converges to the critical value of branching random walks on as the radius increases to infinity. Our main result also implies coexistence of an arbitrary finite number of species for an ecological model.


2021 ◽  
Vol 104 (20) ◽  
Author(s):  
K. Jürgens ◽  
F. Lengers ◽  
D. Groll ◽  
D. E. Reiter ◽  
D. Wigger ◽  
...  

2016 ◽  
Vol 27 (5) ◽  
pp. 738-755 ◽  
Author(s):  
EUNJU SOHN ◽  
CHARLES KNESSL

We consider a storage allocation model with a finite number of storage spaces. There are m primary spaces that are ranked {1,2,. . .,m} and R secondary spaces ranked {m + 1, m + 2,. . .,m + R}. Items arrive according to a Poisson process, occupy a space for a random exponentially distributed time, and an arriving item takes the lowest ranked available space. Letting N1 and N2 denote the numbers of occupied primary and secondary spaces, we study the joint distribution Prob[N1 = k, N2 = r] in the steady state. The joint process (N1, N2) behaves as a random walk in a lattice rectangle. We shall obtain explicit expressions for the distribution of (N1, N2), as well as the marginal distribution of N2. We also give some numerical studies to illustrate the qualitative behaviors of the distribution(s). The main contribution is to study the effects of a finite secondary capacity R, whereas previous studies had R = ∞.


2016 ◽  
Vol 48 (1) ◽  
pp. 215-234 ◽  
Author(s):  
Ross G. Pinsky

Abstract Let N and M be positive integers satisfying 1≤ M≤ N, and let 0< p0 < p1 < 1. Define a process {Xn}n=0∞ on ℤ as follows. At each step, the process jumps either one step to the right or one step to the left, according to the following mechanism. For the first N steps, the process behaves like a random walk that jumps to the right with probability p0 and to the left with probability 1-p0. At subsequent steps the jump mechanism is defined as follows: if at least M out of the N most recent jumps were to the right, then the probability of jumping to the right is p1; however, if fewer than M out of the N most recent jumps were to the right then the probability of jumping to the right is p0. We calculate the speed of the process. Then we let N→ ∞ and M/N→ r∈[0,1], and calculate the limiting speed. More generally, we consider the above questions for a random walk with a finite number l of threshold levels, (Mi,pi) i=1l, above the pre-threshold level p0, as well as for one model with l=N such thresholds.


2002 ◽  
Vol 737 ◽  
Author(s):  
James P. Lavine

ABSTRACTThe time-dependent diffusion of particles to an absorbing sphere is investigated with three random walk models. The first uses consecutive independent particles and finds the capture time distributions are exponential for a range of values of the surface absorption probability. The next two models are of the ensemble variety and assume that only a finite number of particles may be absorbed by the sphere. These models investigate depletion effects and concentration dependence. The latter is probed by varying the initial number of diffusing particles. It is found


2005 ◽  
Vol 42 (01) ◽  
pp. 287-294 ◽  
Author(s):  
Thomas Mountford ◽  
Rinaldo B. Schinazi

We show that a branching random walk that is supercritical on is also supercritical, in a rather strong sense, when restricted to a large enough finite ball of This implies that the critical value of branching random walks on finite balls converges to the critical value of branching random walks on as the radius increases to infinity. Our main result also implies coexistence of an arbitrary finite number of species for an ecological model.


Author(s):  
R. A. Crowther

The reconstruction of a three-dimensional image of a specimen from a set of electron micrographs reduces, under certain assumptions about the imaging process in the microscope, to the mathematical problem of reconstructing a density distribution from a set of its plane projections.In the absence of noise we can formulate a purely geometrical criterion, which, for a general object, fixes the resolution attainable from a given finite number of views in terms of the size of the object. For simplicity we take the ideal case of projections collected by a series of m equally spaced tilts about a single axis.


2020 ◽  
Vol 8 (20) ◽  
pp. 6832-6838 ◽  
Author(s):  
Da Teng ◽  
Kai Wang ◽  
Qiongsha Huan ◽  
Weiguang Chen ◽  
Zhe Li

Tunable ultra-deep subwavelength optical field confinement is reported by using a graphene-coated nanowire-loaded silicon nano-rib waveguide.


Author(s):  
Joseph Rudnick ◽  
George Gaspari
Keyword(s):  

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