What is the Relationship Between Concurrence and Three Tangle in Quantum States?

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Homework Help Overview

The discussion revolves around the relationship between concurrence and three tangle in quantum states, specifically focusing on the calculations involving the GHZ and W states. Participants are exploring the formulas for three tangle and concurrence, as well as their implications in quantum mechanics.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to confirm the formulas for three tangle and its relation to concurrence. Questions are raised about the meaning of the three tangle value ($\tau$) and its expected outcomes for different quantum states. There are requests for examples and methods to calculate the density matrix using three tangle.

Discussion Status

The discussion is ongoing, with participants expressing confusion and seeking clarification on the calculations and theoretical implications. Some have reiterated their need for assistance in calculating tangle manually and have requested code for these calculations. There is no explicit consensus on the formulas or methods being discussed.

Contextual Notes

There are indications that some participants are under time constraints and are seeking urgent help, which may influence the nature of the responses. Additionally, one participant has noted the age of the thread and suggested starting a new thread for further assistance.

munirah
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Good day,

May anyone help me to confirm the formula use for three tangle using concurrence.

From my reading,

three tangle,

$$\tau=\tau_{A(BC)}-\tau_{AB}-\tau_{AC}$$

and it can be related to concurrence

$$\tau=C^2_{A(BC)}-C^2_{AB}-C^2_{AC}$$

and I used formula for C is

$$C^2=2-(Tr\rho^2_1+Tr\rho^2_2)$$ where $$\rho$$ is partial trace.
[FONT=Georgia, Times New Roman, Times, serif]
When I calculate the GHZ state, I get zero. It suppose $$\tau>0$$ for GHZ state and $$\tau=0$$ for W state
[FONT=Georgia, Times New Roman, Times, serif]
May I know, what it mean by the $$\tau$$ here. Please help me.

And How I can calculated the density matrix of the state using three tangle. May anyone show me an example. I'm really stuck. Please help me.

Thank you.

 
Thank you Greg Bernhardt. It is ok for this. I will make other question.
 
munirah said:
Good day,

May anyone help me to confirm the formula use for three tangle using concurrence.

From my reading,

three tangle,

$$\tau=\tau_{A(BC)}-\tau_{AB}-\tau_{AC}$$

and it can be related to concurrence

$$\tau=C^2_{A(BC)}-C^2_{AB}-C^2_{AC}$$

and I used formula for C is

$$C^2=2-(Tr\rho^2_1+Tr\rho^2_2)$$ where $$\rho$$ is partial trace.
[FONT=Georgia, Times New Roman, Times, serif]
When I calculate the GHZ state, I get zero. It suppose $$\tau>0$$ for GHZ state and $$\tau=0$$ for W state
[FONT=Georgia, Times New Roman, Times, serif]
May I know, what it mean by the $$\tau$$ here. Please help me.

And How I can calculated the density matrix of the state using three tangle. May anyone show me an example. I'm really stuck. Please help me.

Thank you.
can you share me how to calculate the tangle. Its very urgent thing for me. And if possible please send me the code for that.
 
Hello,, even I am also struck in this. It is very needed for me. can you please share me how to calculate tangle manually and if you have code please send me. It will be a great helpfull for me. please send me today. Most wanted problem.
 
Appu said:
Hello,, even I am also struck in this. It is very needed for me. can you please share me how to calculate tangle manually and if you have code please send me. It will be a great helpfull for me. please send me today. Most wanted problem.
Welcome to PF. :smile:

This thread is over 5 years old, and the Original Poster (OP) has not been here since 2017. If this is a question for your work, start a new thread in the appropriate technical forum, and show what you have found so far. If this is for schoolwork, start a new thread in the Homework Help forums, and show your work on the problem.

BTW, please do not use text speak like "please" at PF. It is not allowed. Thank you.
 
Sorry for the mistake Sir. It won't repeat again.
Thank you.
 
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