Average entanglement dynamics in open two-qubit systems with continuous monitoring
Abstract
We present a comprehensive implementation of the quantum trajectory theory for the description of the entanglement dynamics in a Markovian open quantum system made of two qubits. We introduce the average concurrence to characterize the entanglement in the system and derive a deterministic evolution equation for it that depends on the ways in which information is read from the environment. This buildt-in flexibility of the method is used to address two actual issues in quantum information: entanglement protection and entanglement estimation. We identify general physical situations in which an entanglement protection protocol based on local monitoring of the environment can be implemented. Additionally, we methodically find unravelings of the system dynamics providing analytical tight bounds for the unmonitored entanglement in the system at all times. We conclude by showing the independence of the method from the choice of entanglement measure.
- Publication:
-
Physical Review A
- Pub Date:
- July 2014
- DOI:
- 10.1103/PhysRevA.90.012338
- arXiv:
- arXiv:1404.1959
- Bibcode:
- 2014PhRvA..90a2338G
- Keywords:
-
- 03.67.Mn;
- 03.67.Pp;
- 03.65.Yz;
- 42.50.Lc;
- Entanglement production characterization and manipulation;
- Quantum error correction and other methods for protection against decoherence;
- Decoherence;
- open systems;
- quantum statistical methods;
- Quantum fluctuations quantum noise and quantum jumps;
- Quantum Physics
- E-Print:
- 15 pages, 4 figures