Questions tagged [wigner-function]
A quasiprobability distribution function proposed to account for quantum corrections to classical statistical mechanics with a goal to link the wavefunction that appears in Schrödinger's equation to a probability distribution in phase space.
10
questions
1
vote
0
answers
44
views
Non-magic non-stabilizer multi-qubit states
Does anyone know of any resources that show examples of simple multi-qubit states which are non-stabilizer states but that are still classically efficiently stimulable? Another way to phrase it is ...
- 1,634
0
votes
1
answer
67
views
Invert colors in qutip plot_wigner function
In QuTiP, it is possible to plot Wigner functions with positive (shown in blue) and negative (shown in red) values.
For example, the following code displays the Wigner function of a Schrodinger cat ...
- 199
1
vote
0
answers
86
views
Are there non-stabilizer multi-qubit states that are easy to simulate?
The Gottesman-Knill theorem states that the following process is efficiently simulatable on a classical computer:
start of with a set of qubits in a computational basis
apply any amount of $H, S$ and ...
- 1,634
1
vote
0
answers
125
views
Evaluation of Wigner function representation of a Bloch Sphere
Consider Wigner function representation of a qubit in the basis labeled by $\sigma_z$ and $\sigma_x$ eigenvalues. A general single qubit mixed state has the Bloch representation,$\rho = 1/2 (I + r.\...
3
votes
0
answers
207
views
Finding Wigner function of four maximal entangled Bell state
How can we find a Wigner function for the four maximally entangled Bell states $(|00\rangle \pm |11\rangle)/\sqrt{2}$, $(|01\rangle \pm |10\rangle)/\sqrt{2}$?
I have used the basis where labels for ...
3
votes
1
answer
84
views
Properties of frames in quasiprobability representation
Let $\mathbb{C}^{d}$ be a complex Euclidean space.
Let $\mathsf{H}(\mathbb{C}^{d})$ be the set of all Hermitian operators, mapping vectors from $\mathbb{C}^{d}$ to $\mathbb{C}^{d}$. I had some ...
- 1,251
2
votes
0
answers
310
views
What is the relation between density matrices and phase-space probability distributions?
According to its tag description, a density matrix is the quantum-mechanical analogue to a phase-space probability measure (probability distribution of position and momentum) in classical statistical ...
- 947
3
votes
1
answer
114
views
Relation between Wigner quasi-probability distribution and statistical second-moment
Is there any relation between the Wigner quasi-probability distribution function $W$ and the statistical second-moment (also known as covariance matrix) of a density matrix of a continuous variable ...
8
votes
1
answer
311
views
Does a Wigner function uniquely determine a quantum state?
We know that the Wigner function of a Gaussian quantum state is (up to a constant) a Gaussian distribution. The first moment and the covariance of this distribution uniquely specify a quantum state. ...
- 203
4
votes
1
answer
1k
views
What does negative probability represent?
"Negative energies and probabilities should not be considered as nonsense. They are well-defined concepts mathematically, like a negative of money." -Paul Dirac
The abstract from Photon-phonon-photon ...
- 3,302