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Md Aquib Molla

Publications and source records attributed to Md Aquib Molla.

6 recordsLinked to original sources

Does Partial Consumption Help Foraging?

In this work, we consider partial consumption of food by a forager in presence of a threshold energy level. The forager considered here can survive for $S$ steps without food, namely the survival time. The threshold limits the consumption of food in such a way that, the forager will only consume food, whenever its energy is below the threshold $k$. Due to partial consumption of food, a site containing food may not always be fully depleted, which in turn helps in increasing the lifetime of the forager. It has been observed that, in our case, the lifetime always increases with $k/S$, although there is a transition threshold $k^*$ below which the increase of lifetime is rapid and above is slow. The transition threshold $k^* \sim \sqrt{S}$. The lifetime $τ$ shows a power law behavior as $τ\sim S^β$. For $k/S=0$, the value of $β$ is $1.331$, it then jumps above $2$ and decreases gradually to $1.833$ with increasing $k/S$. Other important quantities like number of revisits to a site, food statistics etc. have been studied and some interesting scaling behaviors are observed. Although, survival for each time unit requires, on an average, the consumption of one unit of food, the food consumption is not the only factor to control the lifetime of the forager. It has been observed that, the strategy in terms of threshold energy and partial consumption affects the lifetime in a positive way. The collection of sites either fully or partially depleted of food after the death of the forager shows a crossover behavior for $k/S \sim 0.5$.

cond-mat.stat-mech

Moving Detector Quantum Walk with Random Relocation

We study a discrete-time quantum walk in presence of a detector at $x_D$ initially. The detector here is repeatedly removed after a span of $t_R$, the removal time, and reinserted at random locations. Two relocation rules are considered here: In Model~1, the detector is reinserted at any site beyond $x_D$, while in Model~2, reinsertion is done within a restricted window around the position of the detector at that time. Both variants behave like Semi Infinite Walk (SIW) for large $t_R$, where the detector behaves effectively as a fixed boundary. However, in the rapid-relocation regime, i.e., when $t_R$ is small, the behaviours are different. Model~1 permits greater spreading due to unrestricted reinsertion, which is different from Model~2. The time evolution of occupation probability ratio of our walker to that of an infinite walker at $x_D$, i.e., $f(x_D,t)/f_\infty(x_D,t)$, initially show the feature of a SIW upto $t=t_R$, then show some oscillatory behaviour and finally reach a saturation value for both the models. The ratio enhancing under certain conditions of $x_D$ and $t_R$, is a purely quantum mechanical effect. The saturation ratio shows a crossover behavior below and above a removal time $t_R^*$. At sites $x \neq x_D$ the occupation probablity ratios at a certain time reveals that for small $t_R$, the behaviours of the two models are drastically different from each other, as well as from Semi Infinite Walk (SIW), Quenched Quantum Walk (QQW) and Moving Detector Quantum Walk (MDQW). The correlation ratios of the two models with that of Infinite Walk (IW) show interesting time dependence for sites to the left or right of the initial detector position $x_D$.

quant-ph

Forager with intermittent rest: Better for survival?

We study the fate of a forager who searches for food performing a random walk on lattices. The forager consumes the available food on the site it visits and leaves it depleted but can survive up to $S$ steps without food. We introduce the concept of intermittent rest in the dynamics which allows the forager to rest with probability $p$ upon consumption of food. The parameter $p$ significantly affects the lifetime of the forager, showing that the intermittent rest can be beneficial for the forager for chosen parameter values. The study of various other quantities reveals interesting scaling behavior with $p$ and also departure from usual diffusive behavior for $0.5 < p < 1$. In addition to numerical simulations, the problem has been studied with analytical approach in one dimension and the results up to $p < 0.5$ agree with the numerical ones to a large extent.

cond-mat.stat-mech

Percolative Instabilities and Sparse-Limit Fractality in 1T-TaS$_2$

The low-temperature metallic phase of 1T-TaS2 may originate from current- and voltage-driven destabilization of the commensurate charge density wave (CDW) in a strongly correlated Mott insulator, alongside the robust yet rarely realized influence of intrinsic electronic distortions. Electrical pulse-driven transport, combined with second harmonic response, reveals abrupt switching, negative differential resistance (NDR), and multiscale domain-wall reorganization. The free energy analysis identifies a critical order parameter threshold for the Mott-metal transition, with scaling exponents (β approx 1.3) consistent with 2D percolation. The sparse limit fractal dimension D_{f} approx 0.3 at 10 K, rising to approx 0.9 at 300 K, reflects the hierarchical evolution of the conductive pathways throughout the temperature. These findings establish a direct connection between fractal percolation, pulse-induced instabilities, and correlated electron transport, offering a framework for controlled access to non-equilibrium phase transitions in low-dimensional quantum materials.

cond-mat.mes-hall

An Insight of Heart-Like Systems with Percolation

We study the signal percolation through heart-like biological system. Starting from an initial distribution of waiting and inactive cells with probabilities $p$ and $(1-p)$ respectively, the signal propagation is observed in terms of active cells. As the signal enters the system from one end, the number of arrival of active sites at the other end is studied and analysis of the system behaviour is made by varying a few important parameters of the system like $p_{switch}$ (switching probability from inactive to waiting) and $p_{act}$ (switching probability from waiting to active). In this connection, the non-regular heart rhythms are discussed. Fraction of paths percolating through the system shows a transition from $0$ to $1$ near $p=p_c$. Some other important quantities like tortuosity and cluster distribution are discussed. Several critical exponents have been obtained and compared the exponents of standard percolation.

cond-mat.stat-mech

Quantum Walker in Presence of a Moving Detector

In this work, we study the effect of a moving detector on a discrete time one dimensional Quantum Random Walk where the movement is realized in the form of hopping/shifts. The occupation probability $f(x,t;n,s)$ is estimated as the number of detection $n$ and amount of shift $s$ vary. It is seen that the occupation probability at the initial position $x_D$ of the detector is enhanced when $n$ is small which is a quantum mechanical effect but decreases when $n$ is large. The ratio of occupation probabilities of our walk to that of an Infinite walk shows a scaling behavior of $\frac{x_D^2}{n^2}$. It shows a definite scaling behavior with amount of shifts $s$ also. The limiting behaviors of the walk are observed when $x_D$ is large, $n$ is large and $s$ is large and the walker for these cases approach the Infinite Walk, The Semi Infinite Walk and the Quenched Quantum Walk respectively.

quant-ph