11 research outputs found
Description and control of decoherence in quantum bit systems
The description and control of decoherence of quantum bit systems have become a field of increasing interest during the last decade. We discuss different techniques to estimate and model decoherence sources of solid state quantum bit realizations.
At first, we derive a microscopic, perturbation theoretical approach for Lindblad master equations of a spin-Boson model at low temperatures.
A different sort of decoherence is investigate by means of the bistable fluctuator model.
For this particular but nevertheless for solid state qubits relevant noise source, we present a suitably designed dynamical decoupling method (so-called quantum bang-bang).
This works as a high-pass filter, suppressing low frequency parts of the noise most effectively and thus being a promising method to compensate the ubiquituous 1/f noise.
Furthermore, we investigate the behaviour of a two coupled spin system exposed to collective and localized bath.
For this dressed-spin system we receive by means of scaling-analysis in first order a quantum phase diagram.
On that we can identify the various quantum dynamical and entanglement phases
Generation and Suppression of Decoherence in Artificial Environment for Qubit System
It is known that a quantum system with finite degrees of freedom can simulate
a composite of a system and an environment if the state of the hypothetical
environment is randomized by external manipulation. We show theoretically that
any phase decoherence phenomena of a single qubit can be simulated with a
two-qubit system and demonstrate experimentally two examples: one is phase
decoherence of a single qubit in a transmission line, and the other is that in
a quantum memory. We perform NMR experiments employing a two-spin molecule and
clearly measure decoherence for both cases. We also prove experimentally that
the bang-bang control efficiently suppresses decoherence.Comment: 25 pages, 7 figures; added reference
Experimental Aspects of Quantum Computing
Practical quantum computing still seems more than a decade away, and researchers have not even identified what the best physical implementation of a quantum bit will be. There is a real need in the scientific literature for a dialog on the topic of lessons learned and looming roadblocks. These papers, which appeared in the journal of "Quantum Information Processing" are dedicated to the experimental aspects of quantum computing These papers highlight the lessons learned over the last ten years, outline the challenges over the next ten years, and discuss the most promising physical implementations of quantum computing
Optics in Our Time
Optics, Lasers, Photonics, Optical Devices; Quantum Optics; Popular Science in Physics; History and Philosophical Foundations of Physic
References, Appendices & All Parts Merged
Includes: Appendix MA: Selected Mathematical Formulas; Appendix CA: Selected Physical Constants; References; EGP merged file (all parts, appendices, and references)https://commons.library.stonybrook.edu/egp/1007/thumbnail.jp