Hey guys,(adsbygoogle = window.adsbygoogle || []).push({});

I am having issues with understanding the physical nature of pure and mixed states. Maybe you can help me out?

1) A pure state - superposition is a state that consists of different states at the same time. It's like having several waves, each one belonging to an Eigenstate of the Hamilton operator, with known phase and amplitude, that interfere with each other, right?

Does that mean, when I have a pure superposition of |0> and |1>, I can find times and positions, where the wave of |0> has minimal deflection and the wave of |1> is at its peak, so the state looks more like a |1> state?

2) Mixed states are statistical mixtures.

A mixture of |1> and |0> means that the particle is DEFINITELY in one of these two states, but I do only know the corresponding probability.

For an ensemble, that means that for a maximal incoherent mixture, half of the particles will be in |1> and the other half in |0>, right?

Does that mean the description of mixed states is only a result of the observer's lack of knowledge, for example: " I know that physically, the particle must be represented by a wave, that corresponds either to |1> or to |0>, but I only know the amplitudes, not the phases, so I have to describe my system as a statistical mixture"

That's it for the beginning. Would be nice, if someone could clear me up on this. And please don't talk too much about density matrices, I know about the mathematical differences in their respective descriptions.

Best wishes

SchroedingersLion

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# I Mixed states vs pure states - physical POV

Tags:

Have something to add?

Draft saved
Draft deleted

Loading...

Similar Threads - Mixed states pure | Date |
---|---|

B Is a pure state a kind of mixed states? | Sep 2, 2017 |

A Quantum Optics - transition from pure to mixed state | Aug 18, 2017 |

I Decoherence Pure States Into Mixed States | Jul 27, 2017 |

B Does weak measurement cause mixed state? | Jul 1, 2016 |

I Pure and mixed states | May 26, 2016 |

**Physics Forums - The Fusion of Science and Community**