Essays about: "mean-field approximation"

Showing result 1 - 5 of 8 essays containing the words mean-field approximation.

1. 1. Hybrid Microwave Resonator-Nanoscale Conductor Systems

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

   Author : Daniel Larsson Persson; [2023]
   Keywords : Circuit Quantum Electrodynamics; Open Quantum Systems; Gaussian States; Two-Mode Two-Photon Jaynes-Cummings Model; Jaynes-Cummings Model; Lyapunov Equation; Phase-Space Description; Duan Criterion; Entanglement; Light-Matter Interaction; Mean Field; Double Quantum Dot; Harmonic Oscillator; Two-Mode Squeezing; Symplectic Form; GKSL Equation; Lindblad Equation; Physics and Astronomy;

   Abstract : Entanglement is a fundamental aspect of quantum computation and quantum information processes. In this work, we analyse the entanglement of two microwave resonators when connected to a semiconductor double quantum dot. READ MORE

3. 2. 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

4. 3. Neural Networks and Uncertainty Estimation for Financial Asset Predictions

   University essay from KTH/Skolan för elektroteknik och datavetenskap (EECS)

   Author : Robert Cedergren; [2020]
   Keywords : ;

   Abstract : With the capability of modeling complex non-linear mappings, neural networks have obtained state-of-the-art performance on various tasks. However, traditional neural networks are prone to overfitting as they tend to be overconfident on unseen, noisy and incorrectly labeled data. Neither do they produce meaningful representations of uncertainty. READ MORE

5. 4. On two-component Bose-Einstein condensates in a ring

   University essay from Lunds universitet/Matematik (naturvetenskapliga fakulteten)

   Author : Marcus Sköld; [2019]
   Keywords : Mathematics and Statistics;

   Abstract : A Bose-Einstein condensate is a type of gas consisting of one or more types of particles called bosons which are cooled to a temperature very close the absolute zero. Under these conditions the particles all start to occupy their lowest quantum state. READ MORE

6. 5. Combining the GW Approximation with the Hubbard I Approximation for strongly correlated materials

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

   Author : Torsten Strunck; [2019]
   Keywords : GWA; GW Approximation; HIA; Hubbard I Approximation; Hubbard-I Approximation; Hubbard model; DMFT; Dynamical Mean Field Theory; strongly correlated materials; electron correlations; solid state physics; Physics and Astronomy;

   Abstract : In this thesis, the GW approximation (GWA, Green's function G times screened interaction W) and the Hubbard I approximation (HIA) are combined in a non-self-consistent one-shot calculation to determine the electronic structure of a one-dimensional strongly-correlated model. The scheme was chosen to incorporate both screening effects through the GWA and strong on-site correlations through the atomic HIA. READ MORE