The physics of quantum computing, or more generally quantum information processing, has become a research field of its own involving many different areas of condensed matter theory like many-particle effects in and out of equilibrium, interaction effects, time dependent external fields, and, most importantly, phase-coherence of single and many particle states (entanglement). Our proposal of a quantum computer based on the electron-spin in quantum dots has attracted wide interest (being one of the highest cited research papers in the field worldwide) as it points the way to a scalable solid state implementation of quantum computing. We have also pioneered the concept of mobile spin-qubits in the solid state (quantum communication) for which a number of entanglers have been proposed and also schemes for the detection of spin entanglement via noise measurements. Spintronics and spin-based quantum computing in the solid-state have become strongly interconnected fields where fundamental issues related to the spin dynamics of electrons in novel magnetic and non-magnetic semiconductors are at the center of interest. We will continue our study in this direction and plan to work on the following topics:
2.A Relaxation and decoherence of electron and hole spins in quantum dots: Relaxation and dy- namics of electron and hole spins in quantum dots due to spin-orbit and hyperfine interactions. Relaxation and dynamics of nuclear spin configurations due to direct dipolar and RKKY interaction.
2.B Nuclear ferromagnetism in interacting electron gases: Nuclear ferromagnetic phase transition triggered through effective nuclear spin interaction due to hyperfine coupling to an interacting electron gas.
Investigation of the essential non-Fermi-liquid corrections to the electron spin response functions.
2.C Electron transport and spin effects: Spin fluctuations and spin-orbit interactions in mesoscopic dis- ordered 2D electron gases. Corrections to the electron gas characteristics from electron-electron interactions beyond standard Landau-Fermi liquid theory. Cotunneling and transport involving non-Abelian edge states in fractional quantum Hall effect systems.
2.D Quantum computing and entanglement: Production of multipartite entanglement for spin qubits.
Entanglement of ground states and entanglement measures in multipartite qubit systems.