arXiv subjects

Alexey A. Dmitriev

Publications and source records attributed to Alexey A. Dmitriev.

7 recordsLinked to original sources

arXiv2026

A rechargeable AA battery supporting Qi wireless charging

Wireless power transfer is one of the key drivers in modern consumer electronics, as it allows one to enhance the convenience and usability of many devices. However, in most cases, wireless charging is accessible only to devices with incorporated receivers or at least to gadgets with standard charging connectors, such as USB Type-C, that allow to attach an external receiver. We propose a rechargeable battery that has the size and output voltage of a standard AA battery but supports wireless power transfer from charging stations of the widely used Qi standard. The proposed design uses a series resonant circuit with a curved receiving coil, as well as load modulation using detuning capacitors switched by a microcontroller unit to implement a receiver compatible with the Qi Baseline protocol. It also utilizes a number of DC-DC converters to store energy in a Li-ion cell and convert it to the 1.5 V voltage level. Our design is supported by numerical simulations of magnetic field distributions and scattering parameters of the introduced battery coupled to a planar transmitting coil. The performance of the proposed battery has been studied experimentally, including measurements of the maximal distance between the battery and a charging station that allows wireless charging at various rotation angles and the charge curve. The developed battery design facilitates the addition of wireless charging functionality to a wide range of electronic devices in a universal way.

physics.app-ph↗

arXiv2025

Swarmodroid & AMPy: Reconfigurable Bristle-Bots and Software Package for Robotic Active Matter Studies

Large assemblies of extremely simple robots capable only of basic motion activities (like propelling forward or self-rotating) are often applied to study swarming behavior or implement various phenomena characteristic of active matter composed of non-equilibrium particles that convert their energy to a directed motion. As a result, a great abundance of compact swarm robots have been developed. The simplest are bristle-bots that self-propel via converting their vibration with the help of elastic bristles. However, many platforms are optimized for a certain class of studies, are not always made open-source, or have limited customization potential. To address these issues, we develop the open-source Swarmodroid 1.0 platform based on bristle-bots with reconfigurable 3D printed bodies and simple electronics that possess external control of motion velocity and demonstrate basic capabilities of trajectory adjustment. Then, we perform a detailed analysis of individual Swarmodroids' motion characteristics and their kinematics. In addition, we introduce the AMPy software package in Python that features OpenCV-based extraction of robotic swarm kinematics accompanied by the evaluation of key physical quantities describing the collective dynamics. Finally, we discuss potential applications as well as further directions for fundamental studies and Swarmodroid 1.0 platform development.

cond-mat.soft↗

arXiv2025

Micellization in active matter of asymmetric self-propelled particles: Experiments

Active matter composed of self-propelled particles features fascinating self-organization phenomena, spanning from motility-induced phase separation to phototaxis to topological excitations depending on the nature and parameters of the system. In the present paper, we consider micelle formation by active particles with a broken symmetry having a circular back and a sharpened nose toward which the particles accelerate. As we demonstrate in experiments with robotic swarms, such particles can either remain in the isotropic phase or form micelles depending on the location of their center of inertia, in accordance with a recent theoretical proposal [T. Kruglov and A. Borisov, Presentations and Videos to 7th Edition of the International Conference on Particle-based Methods (2021), Vol. CT07, p. 2]. Such a behavior is observed for both nonchiral particles moving linearly and placed in a parabolic potential and for chiral particles moving along circular trajectories on a flat surface. By performing experiments with single robots and two-robot collisions, we unveil that the observed emergence of micellization associated with shifting robots' center of inertia towards their noses is governed by at least two-particle effects, in particular, by a difference in the formation of stable two-robot clusters. Finally, we consider the dependence of micelle lifetime and formation probability as well as two-robot collisions on friction between the lateral surfaces of the robots. Crucially, the predicted micellization does not involve any solvation shells that give rise to the micellization of surfactants but is instead driven by an interplay of activity and particle shape asymmetry.

cond-mat.soft↗

arXiv2023

Retardaion-induced exceptional point

Exceptional points in an optical dimer of spheres, which have the same size and operate in the spectral region of the dipolar resonance, are considered. By choosing different materials of these spheres, we can offset the radiative loss and create a gain-loss contrast to achieve a parity-time (PT)-symmetric dimer. In this case, an exceptional point corresponds to the point where the PT symmetry is broken. At the same time, if we consider a symmetric dimer, where both spheres are made of the same material (which may have a purely real dielectric constant), exceptional points occurring due to the radiative loss non-Hermiticity can also be observed. We study the transition between the two regimes and demonstrate that the exceptional point emerges due to the retardative nature of the coupling between the spheres, which makes the equation for eigenfrequencies nonlinear and allows it to have nontrivial solutions even when there is no contrast between the spheres.

physics.optics↗

arXiv2021

Electric circuit emulation of topological transitions driven by quantum statistics

Topological phases exhibit a plethora of striking phenomena including disorder-robust localization and propagation of waves of various nature. Of special interest are the transitions between the different topological phases which are typically controlled by the external parameters. In contrast, in this Letter, we predict the topological transition in the two-particle interacting system driven by the particles' quantum statistics. As a toy model, we investigate an extended one-dimensional Hubbard model with two anyonic excitations obeying fractional quantum statistics in-between bosons and fermions. As we demonstrate, the interplay of two-particle interactions and tunneling processes enables topological edge states of anyon pairs whose existence and localization at one or another edge of the one-dimensional system is governed by the quantum statistics of particles. Since a direct realization of the proposed system is challenging, we develop a rigorous method to emulate the eigenmodes and eigenenergies of anyon pairs with resonant electric circuits.

quant-ph↗

arXiv2021

Higher-order topological states mediated by long-range coupling in $D_4$-symmetric lattices

Topological physics opens a door towards flexible routing and resilient localization of waves of various nature. Recently proposed higher-order topological insulators provide advanced control over wave localization in the structures of different dimensionality. In many cases, the formation of such higher-order topological phases is governed by the lattice symmetries, with kagome and breathing honeycomb lattices being prominent examples. Here, we design and experimentally realize the resonant electric circuit with $D_4$ symmetry and additional next-nearest-neighbor couplings. As we prove, a coupling of the distant neighbors gives rise to an in-gap corner state. Retrieving the associated invariant directly from the experiment, we demonstrate the topological nature of the designed system, revealing the role of long-range interactions in the formation of topological phases. Our results thus highlight the distinctions between tight-binding systems and their photonic counterparts with long-range couplings.

cond-mat.mes-hall↗

arXiv2019

Strong optical coupling combines isolated scatterers into dimer

We analyze the transition between different coupling regimes of two dielectric rods, which occurs at a critical distance between them. The hallmark of strong coupling regime is the peak splitting effect observed in spectra. Here we comprehensively evaluate the critical distance as a function of the rod permittivity using a number of different approaches. The scattering spectra of the two rods in dependence on the distance demonstrate the weak to strong coupling transition. We start the analysis by introducing a region of a tidal energy flux around a single isolated rod (the region is related to the near field) and demonstrate that its effective radius corresponds to the critical distance obtained from the scattering spectra. Next, we study the eigenfrequencies of the dimer as functions of distance by 'diagonalizing' the coupled multipole matrix. In order to find an analytical formula for the critical distance, we consider the problem under several approximations, which yield similar results.

physics.optics↗