Sökning: "Quantum coherence"
Visar resultat 21 - 25 av 63 avhandlingar innehållade orden Quantum coherence.
21. Entanglement detection schemes and coherent manipulation of spin in quantum dots
Sammanfattning : The work contained in this thesis deals with two closely related topics. Papers I-III deal with charge transport statistics in nanoscale devices to investigate the presence of entanglement in the constituent electrons. We identify the contributions of entangled electron pairs to the current cross-correlations as a signature of entanglement. LÄS MER
22. Light-Matter Interaction and Quantum Computing in Rare-Earth-Ion-Doped Crystals
Sammanfattning : In this thesis, crystals of yttrium orthosilicate (Y2SiO5) that are randomly doped with another rare-earth element, such as praseodymium (Pr), europium (Eu), or cerium (Ce), are investigated with lasers locked to ultra-stable cavities using the Pound-Drever-Hall locking technique. Many of these rare-earth elements have long-lived 4f-4f transitions, hundreds of microseconds to a few milliseconds, with even longer ground hyperfine lifetimes of up to several days. LÄS MER
23. Cerium as a quantum state probe for rare-earth qubits in a crystal
Sammanfattning : Rare-earth ions doped into a transparent crystal can have optically excited states with coherence times of milliseconds and hyperfine levels with coherence times of hours when cooled down to liquid helium temperatures. This makes them attractive for developing quantum computing hardware. LÄS MER
24. Slow and stopped light by light-matter coherence control
Sammanfattning : In this thesis we study light-matter coherence phenomena related to the interaction of a coherent laser field and the so-called Λ-system, a three-level quantum system (e.g., an atom). We observe electromagnetically induced transparency (EIT), slow and stored light in hot rubidium vapor. LÄS MER
25. Quantum memory development and new slow light applications in rare-earth-ion-doped crystals
Sammanfattning : When doped into solid state transparent crystals, rare-earth ions can have optically excited states with milliseconds coherence time and up to six hours coherence time for hyperfine levels after being cooled down to liquid helium temperature. This long coherence property makes them unique as solid state material and attractive for quantum information applications. LÄS MER
