# Representations of two-qubit and ququart states via discrete Wigner functions

@article{Marchiolli2019RepresentationsOT, title={Representations of two-qubit and ququart states via discrete Wigner functions}, author={Marcelo Aparecido Marchiolli and Di{\'o}genes Galetti}, journal={arXiv: Quantum Physics}, year={2019} }

By means of a well-grounded mapping scheme linking Schwinger unitary operators and generators of the special unitary group $\mathrm{SU(N)}$, it is possible to establish a self-consistent theoretical framework for finite-dimensional discrete phase spaces which has the discrete $\mathrm{SU(N)}$ Wigner function as a legitimate by-product. In this paper, we apply these results with the aim of putting forth a detailed study on the discrete $\mathrm{SU(2)} \otimes \mathrm{SU(2)}$ and $\mathrm{SU(4…

## References

SHOWING 1-10 OF 82 REFERENCES

Geometrical meaning of two-qubit entanglement and its symmetries

- Physics
- 2010

For pure and mixed two-qubit states we present an analysis based on symmetries of vectors and matrices associated to the density operator. These symmetries are revealed by doing reflection operations…

On the quantum discord of general X states

- PhysicsQuantum Inf. Process.
- 2015

It is found that the transitions between Q_{\theta }$$Qθ subdomains occur suddenly, but continuously and smoothly, i.e., nonanalyticity is hidden and can be observed in higher order derivatives of discord function.

Phase diagram for the one-way quantum deficit of two-qubit X states

- PhysicsQuantum Inf. Process.
- 2019

This work builds the complete phase diagram of one-way quantum deficit for the XXZ subclass of symmetric X states and instils hope to detect the mysterious fraction of quantum correlation with the variable optimal measurement angle experimentally.

On the discrete Wigner function for SU(N)

- MathematicsJournal of Physics A: Mathematical and Theoretical
- 2019

We present a self-consistent theoretical framework for finite-dimensional discrete phase spaces that leads us to establish a well-grounded mapping scheme between Schwinger unitary operators and…

Extremal properties of conditional entropy and quantum discord for XXZ, symmetric quantum states

- PhysicsQuantum Inf. Process.
- 2017

It is remarkable that the maxima exist in surprisingly wide regions, and the boundaries for such regions are defined by the same bifurcation conditions as for those with a minimum.

Theoretical formulation of finite-dimensional discrete phase spaces: II. On the uncertainty principle for Schwinger unitary operators

- Mathematics
- 2013

Quantifying entanglement of a two-qubit system via measurable and invariant moments of its partially transposed density matrix

- Physics
- 2015

We describe a direct method to determine the negativity of an arbitrary two-qubit state in experiments. The method is derived by analyzing the relation between the purity, negativity, and a universal…

Maximally entangled mixed states of two qubits

- Mathematics
- 2001

In this paper we investigate how much entanglement in a mixed two-qubit system can be created by global unitary transformations. The class of states for which no more entanglement can be created by…

History states of systems and operators

- PhysicsPhysical Review A
- 2018

We discuss some fundamental properties of discrete system-time history states. Such states arise for a quantum reference clock of finite dimension and lead to a unitary evolution of system states…