http://hdl.handle.net/2289/22 2026-04-19T04:18:30Z 2026-04-19T04:18:30Z Del Vecchio Del Vecchio, Giuseppe Kulkarni, Manas Majumdar, Satya N Sabhapandit, Sanjib http://hdl.handle.net/2289/8703 2026-04-15T05:07:59Z 2026-04-02T00:00:00Z

Title: Proxitaxis: An adaptive search strategy based on proximity and stochastic resetting Authors: Del Vecchio Del Vecchio, Giuseppe; Kulkarni, Manas; Majumdar, Satya N; Sabhapandit, Sanjib Abstract: We introduce proxitaxis, a simple search strategy where the searcher has only information about the distance from the target but not the direction. The strategy consists of three crucial components: (i) local adaptive moves with a distance-dependent diffusion coefficient, (ii) intermittent long-range returns via stochastic resetting to a certain location 𝑅0, and (iii) an inspection move where the searcher dynamically updates the resetting position ⃗𝑅0. We compute analytically the capture probability of the target within this strategy and show that it can be maximized by an optimal choice of the control parameters of this strategy. Moreover, the optimal strategy undergoes multiple phase transitions as a function of the control parameters. These phase transitions are generic and occur in all dimensions. Description: Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)

2026-04-02T00:00:00Z Ghosh, Anirban Mandal, Sudipta Chaki, Subhasish http://hdl.handle.net/2289/8686 2026-03-16T11:18:53Z 2026-01-29T00:00:00Z

Title: Anisotropic active Brownian particle in two dimensions under stochastic resetting Authors: Ghosh, Anirban; Mandal, Sudipta; Chaki, Subhasish Abstract: We study the dynamical behavior of an anisotropic active Brownian particle subjected to various stochastic resetting protocols in two dimensions. The motion of shape-asymmetric active Brownian particles in two dimensions leads to anisotropic diffusion at short times, whereas rotational diffusion causes the transport to become isotropic at longer times. We have considered three different resetting protocols: (1) complete resetting, when both position and orientation are reset to their initial states, (2) only the position is reset to its initial state, and (3) only orientation is reset to its initial state. We reveal that orientational resetting sustains anisotropy even at late times. When both the spatial position and orientation are subject to resetting, a complex position probability distribution forms in the steady state. This distribution is shaped by factors such as the initial orientation angle, the anisotropy of the particle, and the resetting rate. We have calculated the exact expressions for mean-square displacements using a renewal approach for different resetting protocols and numerically verified the analytical results. When only the translational degrees of freedom are reset, while the particle's orientation evolves naturally, the steady state no longer depends on particle asymmetry. In contrast, if only the orientation is reset, the long-term probability distribution becomes Gaussian, using an effective diffusion tensor—containing nondiagonal elements—defined by the resetting rate. More broadly, the interaction between translational and rotational dynamics, in combination with stochastic resetting, produces distinct behaviors at late times that are absent in symmetric particles. Given recent progress in experimental resetting techniques, these results could be highly useful for controlling asymmetric active colloids, such as in self-assembly applications. Description: Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)

2026-01-29T00:00:00Z Estake, Kiran Babasaheb Vishnu, T R Roy, Dibyendu http://hdl.handle.net/2289/8678 2026-02-27T11:21:16Z 2025-12-16T00:00:00Z

Title: From chiral topological dynamics to chiral topological amplification: Real versus imaginary parameters in a Hermitian bosonic chain Authors: Estake, Kiran Babasaheb; Vishnu, T R; Roy, Dibyendu Abstract: We propose a Hermitian quadratic bosonic model (QBH) whose dynamical matrix exhibits distinct topological and dynamical phenomena depending on whether the hopping and pairing amplitudes are real or purely imaginary. In the real-parameter regime, the dynamical matrix is unitarily equivalent to four decoupled copies of the sublattice-symmetric non-Hermitian Su-Schrieffer-Heeger (nSSH2) model, thereby inheriting its topological phases and energy spectrum, including the Möbius phase, a gapless topological phase with fractional winding number, having no Hermitian counterpart. We show that the dynamics generated by the QBH Hamiltonian naturally reproduces non-Hermitian time evolution, without invoking nonlinear Schrödinger dynamics or ad hoc normalization. It is demonstrated by analytically calculating the Loschmidt amplitude and computing the dynamical topological order parameter under periodic boundary conditions, which displays a distinct chiral response in the Möbius phase. In contrast, when the hopping and pairing terms are taken to be purely imaginary, the dynamical matrix becomes unitarily equivalent to a different version of the sublattice-symmetric non-Hermitian Su-Schrieffer-Heeger (nSSH1) model that supports only two topological phases, trivial and nontrivial, and the Möbius phase disappears. The latter system exhibits sublattice-dependent chiral amplification under open boundary conditions. We show that this amplification arises from the nontrivial topology of the dynamical matrix, establishing a clear link between topological phase and amplification behavior in the imaginary-parameter regime. Description: Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)

2025-12-16T00:00:00Z Mesquita, Nikhil Kulkarni, Manas Majumdar, Satya N Sabhapandit, Sanjib http://hdl.handle.net/2289/8676 2026-02-27T11:18:49Z 2025-12-05T00:00:00Z

Title: Dynamically generated correlations in a trapped bosonic gas via frequency quenches Authors: Mesquita, Nikhil; Kulkarni, Manas; Majumdar, Satya N; Sabhapandit, Sanjib Abstract: We study a system of N noninteracting bosons in a harmonic trap subjected to repeated quantum quenches, where the trap frequency is switched from one value to another after a random time duration drawn from an exponential distribution. Each cycle contains two steps: (i) changing the trap frequency to enable unitary evolution under a Hamiltonian, and (ii) reapplying the original trap at stochastic times to cool the gas back to its initial state. This protocol effectively makes it an open quantum system and drives it into a unique nonequilibrium steady state (NESS). We analytically and numerically characterize the NESS, uncovering a conditionally independent and identically distributed (CIID) structure in the joint probability density function (JPDF) of the positions. The JPDF in the CIID structure is a product of Gaussians with a common random variance, which is then averaged with respect to its distribution, making the JPDF non-factorizable, giving rise to long-range emergent dynamical correlations. The average density profile of the gas shows significant deviations from the initial Gaussian shape. We further compute the order and the gap statistics, revealing universal scaling in both bulk and edge regimes. We also analyze the full counting statistics, exposing rich parameter-dependent structure. Our results demonstrate how stochastic quenches can generate nontrivial correlations in quantum many-body systems Description: Open Access. Also available at arXiv.org (one of the alternative locations)

2025-12-05T00:00:00Z