arXiv subjects

Madhuri Mukhopadhyay

Publications and source records attributed to Madhuri Mukhopadhyay.

5 recordsLinked to original sources

arXiv2025

Training for Transport and Localization in Quantum System

Through periodic Training we can gradually buildup a reproducible responses in a disordered system where plasticity dominates over elasticity as is known in classical amorphous materials and soft matter 1, 6. Here we show that a similar concept can be extended to disordered quantum systems. Periodic electrical or mechanical driving of a disordered quantum-dot network can sculpt the effective Hamiltonian, producing either a low-energy transport valley that enhances exciton conduction, or a localized regime with many body memory like behavior. Our results establish training as a new paradigm for creating functional order in disordered quantum matter.

cond-mat.mes-hall↗

arXiv2025

Identifying the Nano Interface Through Phase

The quantum dots (QD) interface in solution can play significant roles in electron transfer dynamics for quantum dots-sensitized solar cells and different biological, environmental, and industrial systems. Here, we predict an avenue to identify the contribution of the quantum dots interface created static electric field on the nonlinear optical response (NLO) due to four-wave mixing (FWM), especially for the nanoparticles where surface contribution is high. We implement a way to disentangle the FWM response in QDs originating from the three incoming oscillating laser fields (NLOoscillating) and a contribution (NLOstatic) arising from the three oscillating laser fields and the static electric field caused by the interface. Advanced two-dimensional electronic spectroscopy (2DES) employs phase-resolved heterodyne techniques where FWM response is measured in a particular phase-matched direction, and the response is distinctively phase sensitive. Theoretical analysis shows alteration in the interface can introduce phase variation in the NLOstatic signal, resulting in a distinct change in the 2D-spectra. Our studies establish a range of ionic strength, which can be important to untwine the usual NLO signal (NLOoscillating) from the NLO (NLOstatic) contributed by the interface of quantum dots. This analysis may open up the possibility to study the different kinds of dynamics occurring specifically in the interface and also will pave the path towards different ion interactions through phase change in 2D spectra, and enormous scope will be employing deep learning-assisted phase recognition.

cond-mat.mes-hall↗

arXiv2016

Engineering the De-localized States of Graphene Quantum Dots

Employing a combination of many-body configuration interaction method described by extended Hubbard model along with first principle calculations we predict the emergence of high oscillator strength at near-IR region which originates from the Davydov type of splitting in doped graphene quantum dots (GQD). Incorporation of strain in GQD promotes closely spaced bright states inciting for coherent excitation. Controlling the destructive interference of the functionalized nano graphene quantum states, the dark states can be tuned towards red end ensuing the system as a good candidate for photocell whereas coherent states can be tailored to concentrate the light at very high intensity resulting an opportunity for photonic device

cond-mat.mtrl-sci↗

arXiv2015

Linear and Nonlinear Optical Properties of Graphene Quantum Dots: A Computational Study

Due to the advantage of tunability via size, shape, doping and relatively low level of loss and high extent of spatial confinement, graphene quantum dots (GQDs) are emerging as an effective way to control light by molecular engineering. The collective excitation in GQDs shows both high energy plasmon frequency along with frequencies in the terahertz (THz) region making these systems powerful materials for photonic technologies. Here, we report a systematic study of the linear and nonlinear optical properties of large varieties of GQDs (400 systems) in size and topology utilizing the strengths of both semiempirical and first-principles methods. Our detailed study shows how the spectral shift and trends in the optical nonlinearity of GQDs depends on their structure, size and shape. Among the circular, triangular, stripe, and random shaped GQDs, we find that GQDs with inequivalent sublattice atoms always possess lower HOMO-LUMO gap, broadband absorption and high nonlinear optical coefficients. Also, we find that for majority of the GQDs with interesting linear and nonlinear optical properties have zigzag edges, although reverse is not always true. We strongly believe that our findings can act as guidelines to design GQDs in optical parametric oscillators, higher harmonic generators and optical modulators.

cond-mat.mtrl-sci↗

arXiv2009

Rabi type oscillations in damped single 2D-quantum dot

We present a quantized model of harmonically confined dot atom with inherent damping in the presence of a transverse magnetic field. The model leads to a non hermitian Hamiltonian in real coordinate. We have analytically studied the effects that damping has on the Rabi type oscillations of the system. The model explains the decoherence of Rabi oscillation in a Josephson Junction.

cond-mat.mes-hall↗