Sabre Kais Group

Quantum Information and Quantum Computation

Study of Entanglement and Quantum Phase Transitions

Ever since the appearance of the famous EPR Gedanken experiment, the phenomenon of entanglement, which features the essential difference between classical and quantum physics, has received wide theoretical and experimental attentions. Generally speaking, if two particles are in an entangled state then, even if the particles are physically separated by a great distance, they behave in some respects as a single entity rather than as two separate entities. This nonlocal effect potentially allows entailed communication exceeding the speed of light! It is no doubt that the entanglement has been lying in the heart of the foundation of quantum mechanics.

Recently a desire to understand the quantum entanglement is refueled by the development of quantum computation. Besides quantum computations, entanglement has also been the core of many other active research such as quantum teleportation, dense coding, quantum communication and quantum cryptography. It is believed that the conceptual puzzles posed by entanglement - and discussed more than fifty years - have now become a physical source to brew completely novel ideas that might result in applications.

The main thrust of this project is calculating entanglement for one- and two-dimensional spin systems, atoms, molecules and arrays of quantum dots and relating it to decoherence time, which is a quantity measurable in experiments and of relevance in various proposals for traditional and quantum computer hardware. Of particular interest is to study one or more "impurities" embedded into such systems: the impurity spins will play the role of information-processing units (qubits, in a quantum computer), while the rest of the system will play the role of the "environment". This setup is of direct relevance for information processing with quantum dots, where an important component of the environment is formed by nuclear spins of the substrate.

See PDF Review Article Here

Light harvesting complex to reaction center


Donor to acceptor