Mixed States, Open Systems, and the Density Operator

2015 ◽  
pp. 101-124
Keyword(s):  
Density Operator ◽  
Open Systems ◽  
Mixed States

Geometric phase of mixed states for three-level open systems

2010 ◽  
Vol 82 (6) ◽  
Author(s):  
Yanyan Jiang ◽  
Y. H. Ji ◽  
Hualan Xu ◽  
Li-yun Hu ◽  
Z. S. Wang ◽  
...  
Keyword(s):  
Geometric Phase ◽  
Open Systems ◽  
Mixed States

scholarly journals Experimental Investigation of the Robustness of a New Bell-Type Inequality of Triphoton GHZ States in Open Systems

Entropy ◽  
2021 ◽  
Vol 23 (11) ◽  
pp. 1514
Author(s):  
Jiaqiang Zhao ◽  
Meijiao Wang ◽  
Lianzhen Cao ◽  
Yang Yang ◽  
Xia Liu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Noise Intensity ◽  
Open Systems ◽  
Type Inequality ◽  
Particle Systems ◽  
Mixed States ◽  
Quantum Bit ◽  
Ghz States ◽  
Information Fidelity ◽  
Different Levels

Knowing the level of entanglement robustness against quantum bit loss or decoherence mechanisms is an important issue for any application of quantum information. Fidelity of states can be used to judge whether there is entanglement in multi-particle systems. It is well known that quantum channel security in QKD can be estimated by measuring the robustness of Bell-type inequality against noise. We experimentally investigate a new Bell-type inequality (NBTI) in the three-photon Greenberger–Horne–Zeilinger (GHZ) states with different levels of spin-flip noise. The results show that the fidelity and the degree of violation of the NBTI decrease monotonically with the increase of noise intensity. They also provide a method to judge whether there is entanglement in three-particle mixed states.

scholarly journals Topological Order, Mixed States and Open Systems

2019 ◽  
Vol 26 (03) ◽  
pp. 1950012 ◽  
Author(s):  
Manuel Asorey ◽  
Paolo Facchi ◽  
Giuseppe Marmo
Keyword(s):  
Open Systems ◽  
Quantum Systems ◽  
Topological Phases ◽  
Topological Order ◽  
Mixed States ◽  
Quantum Matter ◽  
Physical Role ◽  
Topological Quantum ◽  
Pure States

The role of mixed states in topological quantum matter is less known than that of pure quantum states. Generalisations of topological phases appearing in pure states have received attention in the literature only quite recently. In particular, it is still unclear whether the generalisation of the Aharonov–Anandan phase for mixed states due to Uhlmann plays any physical role in the behaviour of the quantum systems. We analyse, from a general viewpoint, topological phases of mixed states and the robustness of their invariance. In particular, we analyse the role of these phases in the behaviour of systems with periodic symmetry and their evolution under the influence of an environment preserving its crystalline symmetries.

scholarly journals Dynamical quantum phase transition for mixed states in open systems

2018 ◽  
Vol 98 (13) ◽  
Author(s):  
Haifeng Lang ◽  
Yixin Chen ◽  
Qiantan Hong ◽  
Heng Fan
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Open Systems ◽  
Quantum Phase ◽  
Mixed States
Sign in / Sign up

Export Citation Format

Share Document