Decoherence is the process by which quantum becomes classical; the process by which the determinism of the macroscopic world arises out of the superpositions and entanglements that describe the microscopic one. Fundamental disagreements persist about the philosophical implications of decoherence, but it is commonly understood to result from entanglement between quantum systems and their environment. In nanostructures, the interactions that would lead to such an entanglement may be controlled and isolated, providing a platform to test theories of decoherence at a microscopic level.
Measurements of phase-coherent effects such as weak localization, Aharanov-Bohm oscillations, and nuclear or electron magnetic resonance have shed light on some of the decoherence mechanisms in solid state materials. But gaps remain that are significant for both science and technology. As a graduate student I used weak localization as a probe of decoherence processes in confined structures. At UBC we will examine some of the outstanding problems, such as understanding macroscopic quantum tunneling in single molecule magnets or the low-temperature limits of coherence in solid state structures.
