HorodeckiState
HorodeckiState | |
Produces a Horodecki state | |
Other toolboxes required | none |
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Related functions | BreuerState ChessboardState |
Function category | Special states, vectors, and operators |
HorodeckiState is a function that produces a "Horodecki" bound entangled state in either $M_3 \otimes M_3$ (two-qutrit space) or $M_2 \otimes M_4$. These states were defined in [1] and have the following standard basis representation: \[\rho_a^{3\otimes 3} := \frac{1}{8a+1}\begin{bmatrix}a & 0 & 0 & 0 & a & 0 & 0 & 0 & a \\ 0 & a & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & a & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & a & 0 & 0 & 0 & 0 & 0 \\ a & 0 & 0 & 0 & a & 0 & 0 & 0 & a \\ 0 & 0 & 0 & 0 & 0 & a & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & \tfrac{1}{2}(1+a) & 0 & \tfrac{1}{2}\sqrt{1-a^2} \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & a & 0 \\ a & 0 & 0 & 0 & a & 0 & \tfrac{1}{2}\sqrt{1-a^2} & 0 & \tfrac{1}{2}(1+a)\end{bmatrix}\] and \[\rho_a^{2 \otimes 4} := \frac{1}{7a+1}\begin{bmatrix}a & 0 & 0 & 0 & 0 & a & 0 & 0 \\ 0 & a & 0 & 0 & 0 & 0 & a & 0 \\ 0 & 0 & a & 0 & 0 & 0 & 0 & a \\ 0 & 0 & 0 & a & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & \tfrac{1}{2}(1+a) & 0 & 0 & \tfrac{1}{2}\sqrt{1-a^2} \\ a & 0 & 0 & 0 & 0 & a & 0 & 0 \\ 0 & a & 0 & 0 & 0 & 0 & a & 0 \\ 0 & 0 & a & 0 & \tfrac{1}{2}\sqrt{1-a^2} & 0 & 0 & \tfrac{1}{2}(1+a)\end{bmatrix}.\]
Syntax
- HORO_STATE = HorodeckiState(A)
- HORO_STATE = HorodeckiState(A,DIM)
Argument descriptions
- A: A real number between 0 and 1 that determines which Horodecki state is produced.
- DIM (optional, default [3,3]): The dimensions of the subsystems that the state should act on. Must be one of [3,3] or [2,4].
Examples
Two-qutrit bound entangled state
The following code generates a two-qutrit Horodecki state and verifies that it is bound entangled by checking that it has positive partial transpose and is not separable:
>> rho = HorodeckiState(0.5)
rho =
0.1000 0 0 0 0.1000 0 0 0 0.1000
0 0.1000 0 0 0 0 0 0 0
0 0 0.1000 0 0 0 0 0 0
0 0 0 0.1000 0 0 0 0 0
0.1000 0 0 0 0.1000 0 0 0 0.1000
0 0 0 0 0 0.1000 0 0 0
0 0 0 0 0 0 0.1500 0 0.0866
0 0 0 0 0 0 0 0.1000 0
0.1000 0 0 0 0.1000 0 0.0866 0 0.1500
>> IsPPT(rho)
ans =
1
>> IsSeparable(rho)
Determined to be entangled via the realignment criterion. Reference:
K. Chen and L.-A. Wu. A matrix realignment method for recognizing entanglement. Quantum Inf. Comput., 3:193-202, 2003.
ans =
0
A (2 ⊗ 4)-dimensional bound entangled state
The following code generates a Horodecki state in $M_2 \otimes M_4$ and verifies that it is bound entangled by checking that it has positive partial transpose and is not separable:
>> rho = HorodeckiState(0.5,[2,4])
rho =
0.1111 0 0 0 0 0.1111 0 0
0 0.1111 0 0 0 0 0.1111 0
0 0 0.1111 0 0 0 0 0.1111
0 0 0 0.1111 0 0 0 0
0 0 0 0 0.1667 0 0 0.0962
0.1111 0 0 0 0 0.1111 0 0
0 0.1111 0 0 0 0 0.1111 0
0 0 0.1111 0 0.0962 0 0 0.1667
>> IsPPT(rho,2,[2,4])
ans =
1
>> IsSeparable(rho,[2,4])
Determined to be entangled by not having a 2-copy PPT symmetric extension. Reference:
A. C. Doherty, P. A. Parrilo, and F. M. Spedalieri. A complete family of separability criteria. Phys. Rev. A, 69:022308, 2004.
ans =
0
Source code
Click here to view this function's source code on github.
References
- ↑ P. Horodecki. Separability criterion and inseparable mixed states with positive partial transposition. Phys. Lett. A, 232:333, 1997. E-print: arXiv:quant-ph/9703004