Sökning: "quantum gates"

Visar resultat 1 - 5 av 36 avhandlingar innehållade orden quantum gates.

1. 1. Quantum Holonomies : Concepts and Applications to Quantum Computing and Interferometry

   Författare :David Kult; Erik Sjöqvist; Gunnar Björk; Barry Sanders; Uppsala universitet; []
   Nyckelord :Physics; Quantum Holonomy; Geometric Phase; Quantum Computation; Completely Positive Map; Mixed State; Interferometry; Fysik;

   Sammanfattning : Quantum holonomies are investigated in different contexts.A geometric phase is proposed for decomposition dependent evolution, where each component of a given decomposition of a mixed state evolves independently. It is shown that this geometric phase only depends on the path traversed in the space of decompositions. 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 and Ballistic Nanodevices

   Författare :Ivan Shorubalko; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; III-V semiconductors; low-dimensional structures; nanostructures; ballistic rectifiers; three-terminal ballistic junctions; quantum wires; planar quantum dots; logic gates; harmonic generation; InP; GaInAs; nanoelectronics; Fysik; Physics; nonlinear transport; electron transport; quantum nanodevices; ballistic nanodevices; Fysicumarkivet A:2003:Shorubalko;

   Sammanfattning : In this thesis, electron transport in quantum and ballistic devices was studied. The devices studied here were quantum wires, planar quantum dots, ballistic rectifiers, artificial functional materials, and three-terminal ballistic junctions. The possible application of such devices in the future nanoelectronics was also investigated. LÄS MER

7. 5. Quantum Holonomy for Many-Body Systems and Quantum Computation

   Författare :Vahid Azimi Mousolou; Erik Sjöqvist; Rosario Fazio; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Quantum holonomy; geometric phase; quantum correlations; quantum phase transitions; quantum computation; Natural Science; Naturvetenskap; Physics; Fysik;

   Sammanfattning : The research of this Ph. D. thesis is in the field of Quantum Computation and Quantum Information. A key problem in this field is the fragile nature of quantum states. LÄS MER