0000000000312008

AUTHOR

Souvik Agasti

showing 4 related works from this author

Simulation of matrix product states for dissipation and thermalization dynamics of open quantum systems

2020

Abstract We transform the system/reservoir coupling model into a one-dimensional semi-infinite discrete chain through unitary transformation to simulate the open quantum system numerically with the help of time evolving block decimation (TEBD) algorithm. We apply the method to study the dynamics of dissipative systems. We also generate the thermal state of a multimode bath using minimally entangled typical thermal state (METTS) algorithm, and investigate the impact of the thermal bath on an empty system. For both cases, we give an extensive analysis of the impact of the modeling and simulation parameters, and compare the numerics with the analytics.

Physicsopen quantum systemthermal bathDynamics (mechanics)General Physics and AstronomyDissipationtime-evolving block decimation algorithm01 natural sciences114 Physical sciencesMatrix multiplication010305 fluids & plasmasOpen quantum systemThermalisationQuantum mechanicsalgoritmit0103 physical sciencesminimally entangled typical thermal stateskvanttifysiikka010306 general physicsQuantum
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Nonlinear quantum Langevin equations for bosonic modes in solid-state systems

2017

Based on the experimental evidence that impurities contribute to the dissipation properties of solid-state open quantum systems, we provide here a description in terms of nonlinear quantum Langevin equations of the role played by two-level systems in the dynamics of a bosonic degree of freedom. Our starting point is represented by the description of the system/environment coupling in terms of coupling to two separate reservoirs, modelling the interaction with external bosonic modes and two level systems, respectively. Furthermore, we show how this model represents a specific example of a class of open quantum systems that can be described by nonlinear quantum Langevin equations. Our analysi…

FOS: Physical sciences02 engineering and technology01 natural sciencesOpen quantum systemQuantum mechanics0103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)Point (geometry)010306 general physicsQuantumOptomechanicsParametric statisticsPhysicsQuantum PhysicsCondensed Matter - Mesoscale and Nanoscale Physicsta114Dissipation021001 nanoscience & nanotechnologyNonlinear systemCoupling (physics)solid-state systemsClassical mechanics0210 nano-technologyQuantum Physics (quant-ph)Langevin equationsPhysics - OpticsOptics (physics.optics)Physical Review A
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Numerical simulation of Kerr nonlinear systems : analyzing non-classical dynamics

2019

Abstract We simulate coherent driven free dissipative Kerr nonlinear system numerically using Euler’s method by solving Heisenberg equation of motion and time evolving block decimation (TEBD) algorithm, and demonstrate how the numerical results are analogous to classical bistability. The comparison with analytics show that the TEBD numerics follow the quantum mechanical exact solution obtained by mapping the equation of motion of the density matrix of the system to a Fokker-Plank equation . Comparing between two different numerical techniques, we see that the semi-classical Euler’s method gives the dynamics of the system field of one among two coherent branches, whereas TEBD numerics genera…

PhysicsKerr nonlinear systemComputer simulationBistabilitybistabilitynumeeriset menetelmätDynamics (mechanics)General Physics and Astronomytime-evolving block decimation algorithm01 natural sciences114 Physical sciences010305 fluids & plasmasNonlinear systemsecond order correlation functionfotoniikka0103 physical sciencesStatistical physics010306 general physicskvanttifysiikka
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Numerical simulation of free dissipative open quantum system and establishment of a formula for π

2020

We transform the system/reservoir coupling model into a one-dimensional semi-infinite discrete chain with nearest neighbor interaction through a unitary transformation, and, simulate the dynamics of free dissipative open quantum system. We investigate the consequences of such modeling, which is observed as finite size effect causing the recurrence of particle from the end of the chain. Afterwards, we determine a formula for π in terms of the matrix operational form, which indicates a robustness of the connection between quantum physics and basic mathematics. peerReviewed

PhysicsCouplingComputer simulationUnitary transformationk-nearest neighbors algorithmtiiviin aineen fysiikkaOpen quantum systemMatrix (mathematics)Classical mechanicscondensed matter physicsChain (algebraic topology)Dissipative systemsimulointikvanttifysiikka
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