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Aranya B. Bhattacherjee

Publications and source records attributed to Aranya B. Bhattacherjee.

At least 19 recordsLinked to original sources
arXiv2022

Influence of refractive index in light scattering measurements of biological particles

Investigations on diverse particulate matter can be carried out by non-invasive and non-destructive analytical means of light scattering technique. Exploration of small particles using this tool must address the concept of refractive index accurately. Interpretation of light scattering results for quantification of morphology of biological particles like viruses and bacterial cells can only be validated by exact evidence of its refractive index. Size and shape quantification of such particles by collecting information from the scattered light, was reported earlier by many researchers but parameter like refractive index was considered as a standard value employed from literature or selected as a median value of biological particles which are alike. A strong analysis is needed on inclusion of appropriate value of refractive index for revelation of light scattering results. This important perception is otherwise not considered strongly in similar works reported earlier. We primarily took an attempt to find the influence of refractive index in light scattering studies with allusion to biological particles like Staphylococcus aureus, Escherichia coli, Corona virus (SARS COV 2) etc.

physics.optics↗
arXiv2020

Coherent control of quantum and entanglement dynamics via periodic modulations in optomechanical semi-conductor resonator coupled to quantum-dot excitons

We systematically study the influence of simultaneously modulating the input laser intensity and quantum dot (QD) resonance frequecy on the mean-field dynamics, fluctuation energy transfer and entanglement in a optomechanical semi-conductor resonator embedded with a QD. We show that the modulation and the hybrid system can be engineered to attain the desired mean-field values, control the fluctuation energy transfer and the entanglement between the various degrees of freedom. A remarkably high degree of entanglement can be achieved by modulating only the QD frequency. The interplay between the two modulations leads to an entanglement which lies between that generated solely by modulating either the QD or the pump laser intensity. A transition from low stationary to large dynamical entanglement occurs as we switch on the modulation. This study opens up new possibilities for optimal control strategies and can be used for data signal transfer and storage in quantum communication platforms.

quant-ph↗
arXiv2019

Controllable Normal mode splitting and Switching performance in hybrid optomechanical semiconductor microcavity containing single quantum dot

We theoretically explore optical bistability for possible signature of all optical switching and their performance in a hybrid quantum optomechanical system comprising of two semiconductor microcavity coupled optically. One of the cavity is driven by an external optical pump laser while the second cavity which contains a quantum dot is indirectly driven by light transmitted from the first cavity. The generated bistable behavior due to optomechanical nonlinearity shows a typical optical switching behavior and it can be controlled by changing the laser power, QD cavity coupling, rocking parameter, and the optomechanical coupling. A clear signature of energy exchange between mechanical optical modes is visible from the mechanical displacement spectrum. These results suggest that the present system can be used for an application in sensitive optical switch and optical sensors.

quant-ph↗
arXiv2019

Nonlinear optical response properties of a quantum dot embedded in a semiconductor microcavity : possible applications in quantum communication platforms

We theoretically investigate optical bistability, mechanically induced absorption (MIA) and Fano resonance of a hybrid system comprising of a single quantum dot (QD) embedded in a solid state microcavity interacting with the quantized cavity mode and the deformation potential associated with the lattice vibration. We find that the bistability can be tuned by the QD-cavity mode coupling. We further show that the normalized power transmission displays anomalous dispersion indicating that the system can be used to generate slow light. We also demonstrate the possibility of using the system as all optomechanical Kerr switch.

quant-ph↗
arXiv2018

Heisenberg Operator Approach for Spin Squeezing Dynamics

We reconsider the one-axis twisting Hamiltonian, which is commonly used for generating spin squeezing, and treat its dynamics within the Heisenberg operator approach. To this end we solve the underlying Heisenberg equations of motion perturbatively and evaluate the expectation values of the resulting time-dependent Heisenberg operators in order to determine approximately the dynamics of spin squeezing. Comparing our results with those originating from exact numerics reveals that they are more accurate than the commonly used frozen spin approximation.

cond-mat.quant-gas↗
arXiv2017

Measuring finite-range phase coherence in an optical lattice using Talbot interferometry

One of the important goals of present research is to control and manipulate coherence in a broad variety of systems, such as semiconductor spintronics, biological photosynthetic systems, superconducting qubits and complex atomic networks. Over the past decades interferometry of atoms and molecules has proven to be a powerful tool to explore coherence. Here we demonstrate a near-field interferometer based on the Talbot effect, which allows to measure finite-range phase coherence of ultracold atoms in an optical lattice. We apply this interferometer to study the build-up of phase coherence after a quantum quench of a Bose-Einstein condensate residing in a one-dimensional optical lattice. Our technique of measuring finite-range phase coherence is generic, easy to adopt, and can be applied in practically all lattice experiments without further modifications.

quant-ph↗
arXiv2015

Optomechanical Entanglement between an Ion and an Optical Cavity Field

We study an optomechanical system in which the mechanical motion of a single trapped ion is coupled to a cavity field for the realization of a strongly quantum correlated two-mode system. We show that for large pump intensities the steady state photon number exhibits bistable behaviour. We further analyze the occurrence of normal mode splitting (NMS) due to mixing of the fluctuations of the cavity field and the fluctuations of the ion motion which indicates a coherent energy exchange. We also find that in the parameter regime where NMS exists, the steady state of the system shows continuous variable entanglement. Such a two-mode optomechanical system can be used for the realization of continuous variable quantum information interfaces and networks.

quant-ph↗
arXiv2015

Non equilibrium dynamics of an optomechanical Dicke model

Motivated by the experimental realization of Dicke model in optical cavities, we model an optomechanical system consisting of a two level BEC with transverse pumping. We investigate the transition from normal and inverted state to the superradiant phase through a detailed study of the phase portrait of the system. The rich phase portrait generated by analytic arguments displays two types of superradiant phases, regions of coexistence and some portion determining the persistent oscillations. We study the time evolution of the system from any phase and discuss the role of mirror frequency in achieving the attractors and stable values. Further, we add an external mechanical pump to the mirror which is capable of changing the mirror frequency and study the impact of the pump on the phase portraits and the dynamics of the system. We find the external mirror frequency changing the phase portraits and even shifting the critical transition point, thereby predicting a system with controllable phase transition.

quant-ph↗
arXiv2014

Influence of Virtual Photon Process on the Generation of Squeezed Light from Atoms in an Optical Cavity

We show that a collection of two-level atoms in an optical cavity beyond the rotating wave approximation and in the dispersive and strong-coupling regime constitutes a nonlinear medium and is capable of generating squeezed state of light. It is found that squeezing produced in the strong-coupling regime is significantly higher compared to that produced in the dispersive limit. On the other hand, we also show that it could be possible to observe the Dicke superradiant quantum phase transition in the dispersive regime where the vector potential term is negligible. Such a system can be an essential component of a larger quantum-communication system.

quant-ph↗
arXiv2014

Selective entanglement in a two-mode optomechanical system

We analyze an optomechanical system formed by a mechanical mode and the two optical modes of an optomechanical cavity for the realization of a strongly quantum correlated three-mode system. We show that the steady state of the system shows three possible bipartite continuous variable entanglements in an experimentally accessible parameter regime, which are robust against temperature. We further show that selective entanglement between the mechanical mode and any of the two optical modes is also possible by the proper choice of the system parameters. Such a two-mode optomechanical system can be used for the realization of continuous variable quantum information interfaces and networks.

quant-ph↗
arXiv2012

Phonon Laser Effect and Dicke-Hepp-Lieb Superradiant Phase Transition in Magnetic Cantilever Coupled to a Bose Einstein Condensate

We propose a possibility of a phonon laser by coupling a Bose-Einstein condensate to a nanomechanical cantilever with a magnetic tip. Due to the magnetic coupling, atomic spin flips induce cantilever motion which can be used to produce a phonon laser. The system is described by the equivalent of the Jaynes-Cummings Hamiltonian. By controlling the number of atoms and the population inversion, one can obtain either a continuous wave (cw) or transient lasing. The two-body atom-atom interaction is also shown to coherently manipulate the lasing process. We also show that in the strong coupling limit, the same system can undergo a Dicke-Hepp-Lieb superradiant phase transition. Exotic phase diagrams can be obtained by tuning the two body atom-atom interaction.

cond-mat.quant-gas↗
arXiv2011

Amplitude and phase mode in a Bose Einstein condensate

We show that starting from the Heisenberg equations of motion for Bose annihilation and creation operators and using an appropriate transformation, we can split the Bogoliubov mode into a free particle mode and the amplitude mode. We show this for both the free Bose gas as well as the Bose gas in an optical lattice.

cond-mat.quant-gas↗
arXiv2011

Non Degenerate Dual Atomic Parametric Amplifier: Entangled Atomic Fields

In this paper, we investigate the dynamics of two coupled quantum degenerate atomic fields (BEC) interacting with two classical optical fields in the nonlinear atom optics regime. Two photon interaction produces entangled atom-atom pairs which exhibit nonclassical correlations. Since the system involves the creation of two correlated atom pairs, we call it the nondegenerate dual atomic parametric amplifier.

cond-mat.quant-gas↗
arXiv2011

Collapse and revival of oscillations in a parametrically excited Bose-Einstein condensate in combined harmonic and optical lattice trap

In this work, we study parametric resonances in an elongated cigar-shaped BEC in a combined harmonic trap and a time dependent optical lattice by using numerical and analytical techniques. We show that there exists a relative competition between the harmonic trap which tries to spatially localize the BEC and the time varying optical lattice which tries to delocalize the BEC. This competition gives rise to parametric resonances (collapse and revival of the oscillations of the BEC width). Parametric resonances disappear when one of the competing factors i.e strength of harmonic trap or the strength of optical lattice dominates. Parametric instabilities (exponential growth of Bogoliubov modes) arise for large variations in the strength of the optical lattice.

cond-mat.quant-gas↗
arXiv2009

Probing superfluidity of periodically trapped ultracold atoms in a cavity by transmission spectroscopy

We study a system of periodic Bose condensed atoms coupled to cavity photons using the input-output formalism. We show that the cavity will either act as a through pass Lorentzian filter when the superfluid fraction of the condensate is minimum or completely reflect the input field when the superfluid fraction is maximum. We show that by monitoring the ratio between the transmitted field and the reflected field, one can estimate the superfluid fraction.

cond-mat.quant-gas↗
arXiv2008

Quantum phases of light coupled to a periodic Bose-Einstein condensate in a cavity

We study a composite photon-Bose condensed atoms (BEC) system in an optical lattice confined in a cavity. We show that the system is able to produce an effective photon-photon repulsion in the presence of an external pump. We predict for the first time zero-temperature quantum phases of light coupled to BEC in the photon blockade regime in the presence of an external pump.

cond-mat.stat-mech↗
arXiv2008

Damping in 2D and 3D dilute Bose gases

Damping in 2D and 3D dilute gases is investigated using both the hydrodynamical approach and the Hartree-Fock-Bogoliubov (HFB) approximation . We found that the both methods are good for the Beliaev damping at zero temperature and Landau damping at very low temperature, however, at high temperature, the hydrodynamical approach overestimates the Landau damping and the HFB gives a better approximation. This result shows that the comparison of the theoretical calculation using the hydrodynamical approach and the experimental data for high temperature done by Vincent Liu (PRL {\bf21} 4056 (1997)) is not proper. For two-dimensional systems, we show that the Beliaev damping rate is proportional to $k^3$ and the Landau damping rate is proportional to $ T^2$ for low temperature and to $T$ for high temperature. We also show that in two dimensions the hydrodynamical approach gives the same result for zero temperature and for low temperature as HFB, but overestimates the Landau damping for high temperature.

cond-mat.other↗