Essays about: "Beyond mean-field"

Found 5 essays containing the words Beyond mean-field.

1. 1. Error propagation in nuclear models

   University essay from Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionen

   Author : Artis Mucenieks; [2023]
   Keywords : Physics and Astronomy;

   Abstract : In this thesis we perform error analysis of a nuclear model based on density-functional theory developed in Lund. The Lund model allows us to perform calculations of nuclear spectra more efficiently by constructing a simple effective Hamiltonian reproducing the quadrupole deformation and pairing interaction strength parameters of a spherical Hartree-Fock reference functional. READ MORE

3. 2. Beyond the Gross-Pitaevskii Equation: A Perturbative Approach

   University essay from Lunds universitet/Fysiska institutionen; Lunds universitet/Teknisk fysik (CI)

   Author : Anton Johansson; [2023]
   Keywords : Gross-Pitaevskii; Beyond mean-field; Many-body Perturbation Theory; Bose-Einstein Condensate; BEC; Physics and Astronomy;

   Abstract : We propose and implement a beyond Gross-Pitaevskii approach based on Many-Body Perturbation theory (MBPT) for the study of Bose-Einstein Condensate (BECs) ground states. Two partitions of the system Hamiltonian are considered. READ MORE

4. 3. Rotational Properties of Lee-Huang-Yang Bosonic Condensates from One to Two Dimensions

   University essay from Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionen

   Author : Hjalmar Holmström; [2022]
   Keywords : BEC; Bose-Einstein condensate; quantum fluid; Quantum mechanics; LHY; LHY-fluid; Lee-Huang-Yang; Rotating BEC; BEC droplet; Physics and Astronomy;

   Abstract : This thesis covers the work of a numerical examination of the rotational properties of a two-component Bose-Einstein condensate (BEC) utilizing the beyond mean-field extended Gross-Pitaevskii equation for a specified set of parameters. These parameters are chosen to cancel the strength of the mean-field interaction, which makes the system predominantly governed by the next order beyond the mean-field Lee-Huang-Yang (LHY) term. READ MORE

5. 4. Beyond Mean-Field Description of Bose-Einstein Condensate

   University essay from Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionen

   Author : Daniel Larsson Persson; [2021]
   Keywords : Bose-Einstein condensate; BEC; dilute; non-uniform; quantum depletion; second quantisation; mean field; mean-field approximation; the Gross-Pitaevskii equation; Gross-Pitaevskii; perturbation theory; many-body perturbation theory; Rayleigh-Schrödinger perturbation theory; Rayleigh-Schrödinger; Epstein-Nesbet perturbation theory; Epstein-Nesbet; quantum ring; Physics and Astronomy;

   Abstract : This thesis work is on the theoretical description of dilute Bose-Einstein condensates (BEC) that are non-uniform, meaning that more than one single-particle state is occupied. This phenomenon is usually called quantum depletion. READ MORE

6. 5. Real-time stability and dynamics of vortices in quasi-two-dimensional self-bound two-component Bose-Einstein condensate

   University essay from Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionen

   Author : Philipp Stürmer; [2019]
   Keywords : Bose-Einstein condensate; bosons; self-bound; cold atom gases; vortex; Physics and Astronomy;

   Abstract : This thesis presents a numerical study of the beyond mean field extended Gross-Pitaevskii equation for a two-component self-bound Bose-Einstein condensate, supplemented by analytical work. We extend the quasi-two-dimensional system's mean field particle-particle contact interaction by quantum fluctuations (LHY-correction). READ MORE