Sökning: "quantum control"

Visar resultat 1 - 5 av 178 avhandlingar innehållade orden quantum control.

1. 1. A General Formalism for Continuous Feedback Control in Quantum Systems

   Författare :Björn Annby-Andersson; NanoLund: Centre for Nanoscience; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; quantum measurements; quantum control; stochastic thermodynamics; information thermodynamics; full count- ing statistics; open quantum systems; Quantum measurements; Quantum control; Stochastic thermodynamics; Information thermodynamics; Full counting statistics; Open quantum systems;

   Sammanfattning : This thesis devolops a general formalism for continuous feedback control in quantum systems. The main result is a quantum Fokker-Planck master equation describing the joint dynamics of a quantum system and a detector with finite bandwidth. For a fast detector, this equation can be reduced to a Markovian master equation for the system dynamics. LÄS MER

3. 2. On the role of the electron-electron interaction in two-dimensional quantum dots and rings

   Författare :Erik Waltersson; Eva Lindroth; Stephanie Reimann; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum dot; quantum ring; quantum dot molecule; electronic structure; two-dimensional; many-body physics; many-body perturbation theory; coupled cluster; coupled cluster singles and doubles; quantum logical gates; quantum computing; quantum control; quantum control algorithm; Electronic structure; Elektronstruktur; fysik; Physics;

   Sammanfattning : Many-Body Perturbation Theory is put to test as a method for reliable calculations of the electron-electron interaction in two-dimensional quantum dots. We show that second order correlation gives qualitative agreement with experiments on a level which was not found within the Hartree-Fock description. LÄS MER

4. 3. Machine learning for quantum information and computing

   Författare :Shahnawaz Ahmed; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; quantum machine learning; quantum process tomography; quantum information; Machine learning; generative neural networks; variational quantum algorithms; quantum state tomography; optimization; quantum computing; Bayesian estimation;

   Sammanfattning : This compilation thesis explores the merger of machine learning, quantum information, and computing. Inspired by the successes of neural networks and gradient-based learning, the thesis explores how such ideas can be adapted to tackle complex problems that arise during the modeling and control of quantum systems, such as quantum tomography with noisy data or optimizing quantum operations, by incorporating physics-based constraints. LÄS MER

5. 4. Quantum-Dot Heat Engines

   Författare :Martin Josefsson; NanoLund: Centre for Nanoscience; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; quantum dot; heat engine; thermoelectric; quantum thermodynamics; quantum transport; Fysicumarkivet A:2020:Josefsson;

   Sammanfattning : This thesis explores the possibilities of using quantum dots (QDs) in nanoscale energy har- vesters converting heat into electrical energy, i.e. heat engines. From a theory perspective, these possibilities have been investigated for almost two decades, and interest in them seem to continuously increase over time. LÄS MER

7. 5. Quantum technologies for secure communications

   Författare :Junior Ricardo Gonzales Ureta; Ana Predojević; Marcus Huber; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum technologies; quantum information; quantum optics; Physics; fysik;

   Sammanfattning : Quantum technologies promise to revolutionize a variety of fields such as metrology, cryptography or computing, among others. The resources that quantum mechanics offers allow us to design faster optimization algorithms, to improve security in communications, and to measure quantities beyond the grasp of current technology. LÄS MER