# A. Ravi P. Rau

## Alumni Professor of Physics

Ph.D., 1970 - University of Chicago

Louisiana State University

Department of Physics & Astronomy

223 Nicholson Hall, Tower Dr.

Baton Rouge, LA 70803-4001

225-578-6841-Office

arau@phys.lsu.edu

Personal Home Page

## Research Interests

### Atomic Theory and Quantum Information

Currently, I am exploring a general analytical technique for solving time-dependent operator equations through a succession of unitary integrations. The Bloch-Liouville equation for a (2j+1)-level system in time-dependent fields is of particular interest, along with current topics in nuclear magnetic resonance and quantum bits. The method extends to dissipation and decoherence which are of great interest in quantum information and quantum computing. Proceeding in analogy to the Bloch sphere construction for a single spin (two-level system), a geometrical construction describes higher dimensional spheres and other manifolds for two-spin and larger systems. A related investigation is to alter the evolution of entanglement between two spins in the presence of dissipation and decoherence. The so-called sudden death of entanglement can be delayed or averted by suitable local actions on the two spins.

Our recent interest is in the area of quantum information: studies of entanglement and other correlations such as quantum discord, their evolution under dissipative and decoherent processes and how they may be controlled, geometrical and symmetry studies of operators and states of N qubits and connections between the Lie and clifford algebras involved with topics in projective geometry and design theory.

### Current and Select Publications

- The Beauty of Physics: Patterns, Principles, and Perspectives, Oxford University Press,
2014. A. R. P. Rau
- “Manipulation of entanglement sudden death in an all optical experimental set-up,”
(with Ashutosh Singh, S. Pradyumna, and U. Sinha), J. Opt. Soc. Am. B 34, 681-690
(2017).
- “Shared symmetries of the hydrogen atom and the two-qubit system,” (with G. Alber),
Topical Review J. Phys. B: At. Mol. Opt. Phys. 50, 242001 (2017).
- “Symmetries and Geometries of Qubits, and their Uses,” Symmetry. 12, 1732 (21 pp)
(2021).
- “Mapping qubit algebras to combinatorial designs,” (with J. P. Marceaux), Quantum Inf. Process. 19, 49 (2020).