Dissipative dynamics of a Harmonic Oscillator : A non-perturbative approach

Starting from a microscopic theory, we derive a master equation for a harmonic oscillator coupled to a bath of non-interacting oscillators. We follow a non-perturbative approach, proposed earlier by us for the free Brownian particle. The diffusion constants are calculated analytically and the positivity of the Master Equation is shown to hold above a critical temperature. We compare the long time behaviour of the average kinetic and potential energies with known thermodynamic results. In the limit of vainishing oscillator frequency of the system, we recover the results of the free Brownian particle.Comment: 7 pages, 3 figure

Dissipative Quantum System and Energy Balance

We discuss how various parts of a quantum many-body system exchange energies at thermal equilibrium. To show this, we assume a quantum system is coupled to a many-body environment (at thermal equilibrium with a bigger environment) consisting of a large number of independent and non-interacting quantum harmonic oscillators above a stable ground state. Once the coupling to a large environment is switched on, the system dissipates its energy continuously to the environment until it reaches equilibrium with the latter. We use the Quantum Langevin equation to show such energy exchange at equilibrium. We conclude that different parts of a physical system can exchange energies even at absolute zero temperature

Multiple ocean parameter-based potential fishing zone (PFZ) location generation and validation in the Western Bay of Bengal

A new conceptual framework based on satellite data, including chlorophyll (CHL), sea surface temperature (SST) fronts, relative winds, current vectors, Ekman transport, and eddies, has been developed to identify potential fishing zones (PFZ) in the Bay of Bengal (BoB). The framework aims to provide persistent forecasts, even under cloudy conditions, based on feature propagation. The validation of the PFZ was carried out using fish catch data collected by the Fishery Survey of India (FSI) between 2016 and 2018. Hooking rates (HR) from longlines and catch per unit effort (CPUE) from trawl nets were used to analyse the data points in hook rate categories (1.0–3.0 and > 3.0) and CPUE categories (50–100 kg and > 100 kg) and interpret them with the PFZ maps. The analysis showed that the high fish catch locations were consistent with persisting features in the BoB, such as high chlorophyll patches, SST fronts, and cyclonic eddies. The high fish catch locations based on hook rate and high CPUE were found to be collocated with the high chlorophyll persisting features and thermal gradients in the BoB. The regression analysis shows that availability of the food (CHL) had the strongest correlation with fish catch, followed by the comfort condition (fronts and eddies)

Low temperature Thermodynamics in the Context of Dissipative Diamagnetism

We revisit here the effect of quantum dissipation on the much - studied problem of Landau diamagnetism, and analyze the results in the light of the third law of thermodynamics. The case of an additional parabolic potential is separately assessed. We find that dissipation arising from strong coupling of the system to its environment qualitatively alters the low-temperature thermodynamic attributes such as the entropy and the specific heat

Third law of thermodynamics for the dissipative cyclotron motion

We derive the heat capacity and the entropy of an exactly solvable model of a charged particle in the combined presence of a uniform homogeneous magnetic field and a finite dissipative quantum heat bath consisting of non interacting harmonic oscillators. The quantities are calculated from the reduced partition function of the damped system which is calculated using the imaginary time functional integral method within the framework of the well known microscopic system-plus-bath model. Unlike the typical choice of an ohmic spectral density of the bath oscillators, we consider the quantum heat bath is having a spectral density corresponding to a thermal harmonic noise. Subsequently we analyse the specific heat and entropy at low and high temperatures. The specific heat and the entropy obtained satisfy the third law of thermodynamics. The heat capacity vanishes as the temperature approaches its absolute zero value, as predicted by the third law of thermodynamics, and satisfies the classical equipartition theorem at high temperatures

Modelling of wave propagation over a submerged sand bar using SWASH

A non-hydrostatic numerical model ‘SWASH’ (Simulating WAves till SHore) is used to study the wave propagation over a submerged sand bar in a wave flume. The SWASH model is calibrated and further used to validate the wave propagation for two different cases. The wave heights and wave induced velocities obtained from the model and the laboratory experimental resultsare compared. The model without the morphology feedback provided good correlation with the measurements for case of low wave energy, whereas for the case of a moderately high wave energy, due to significant variations in the bed morphology, the model under-performed towards the later part of the simulation. However, incorporating a modified bathymetry considering the variation in the bed morphology, the model results were reasonable

Modelling of wave propagation over a submerged sand bar using SWASH

1177-1182<span style="font-size:11.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">A non-hydrostatic numerical model ‘SWASH’ (Simulating WAves till SHore) is used to study the wave propagation over a submerged sand bar in a wave flume. The SWASH model is calibrated and further used to validate the wave propagation for two different cases. The wave heights and wave induced velocities obtained from the model and the laboratory experimental resultsare compared. The model without the morphology feedback provided good correlation with the measurements for case of low wave energy, whereas for the case of a moderately high wave energy, due to significant variations in the bed morphology, the model under-performed towards the later part of the simulation. However, incorporating a modified bathymetry considering the variation in the bed morphology, the model results were reasonable.</span