Sökning: "Quantum Phase Transitions"
Visar resultat 1 - 5 av 46 avhandlingar innehållade orden Quantum Phase Transitions.
Sammanfattning : The research of this Ph. D. thesis is in the field of Quantum Computation and QuantumInformation. A key problem in this field is the fragile nature of quantum states. LÄS MER
Sammanfattning : Condensed matter systems undergoing phase transitions rarely allow exact solutions. The presence of disorder renders the situation even worse but collective Monte Carlo methods and parallel algorithms allow numerical descriptions. LÄS MER
Sammanfattning : This thesis deals with large networks of limit cycle oscillators. A limit cycle oscillator is a dynamical system that has a periodic attractor in phase space, and is defined in continuous time. To each such oscillator one can associate a natural frequency. LÄS MER
Sammanfattning : Superconductivity is a macroscopic quantum phenomenon, in the sense that a macroscopic number of electrons form a pair condensate, that occupies a single ground state. The electrons in this state are phase-coherent, breaking global U (1)-symmetry, and spatial variations of the phase imply superflows that usually cost kinetic energy, resulting in a uniform and rigid phase. LÄS MER
Sammanfattning : The author of this thesis concentrates his attention on quantum optical properties of some artificial electromagnetic media, such as quantum coherent atomic vapors (various multilevel electromagnetically induced transparency vapors) and negative refractive index materials, and suggests some possible ways to manipulate wave propagations inside the artificial electromagnetic materials based on quantum coherence and quantum vacuum effects. In Chapters 1 and 2, the author reviews the previous papers on quantum coherence as well as the relevant work such as electromagnetically induced transparency (EIT), atomic population trapping and their various applications. LÄS MER