# Entanglement universality of two-qubit X-states

@article{Mendonca2014EntanglementUO, title={Entanglement universality of two-qubit X-states}, author={Paulo E. M. F. Mendonca and Marcelo Aparecido Marchiolli and Di{\'o}genes Galetti}, journal={Annals of Physics}, year={2014}, volume={351}, pages={79-103} }

## Figures from this paper

## 42 Citations

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…

Two-qubit mixed states and teleportation fidelity: purity, concurrence, and beyond

- Computer ScienceThe European Physical Journal D
- 2018

By computing teleportation fidelity, concurrence and purity for two-qubit X-states, it is shown that fidelity changes monotonically with respect to functions of parameters – other than concurrenceand purity.

Simulating of X-states and the two-qubit XYZ Heisenberg system on IBM quantum computer

- PhysicsPhysica Scripta
- 2022

Two qubit density matrices which are of X-shape, are a natural generalization of Bell Diagonal States (BDSs) recently simulated on the IBM quantum device. We generalize the previous results and…

Characterizing qubit channels in the context of quantum teleportation

- Physics
- 2021

We consider a scenario where a party, say, Alice prepares a pure two-qubit (either maximally entangled or non-maximally entangled) state and sends one half of this state to another distant party,…

Fidelity deviation in quantum teleportation with a two-qubit state

- PhysicsJournal of Physics A: Mathematical and Theoretical
- 2020

Quantum teleportation with an arbitrary two-qubit state can be appropriately characterized in terms of maximal fidelity and fidelity deviation. The former quantifies optimality of the process and is…

Heuristic for estimation of multiqubit genuine multipartite entanglement

- Computer Science
- 2015

This paper provides the first characterization of GM-entanglement in the steady states of the driven Dicke model at zero temperature and introduces and benchmark a heuristic for estimating the GM-concurrence of an arbitrary multiqubit mixed state.

Asymmetric steerability of quantum equilibrium and nonequilibrium steady states through entanglement detection

- PhysicsPhysical Review A
- 2021

Einstein-Podolsky-Rosen steering describes a quantum correlation in addition to entanglement and Bell nonlocality. However, conceptually different with entanglement and Bell nonlocality, quantum…

Local available quantum correlations of X states: The symmetric and anti-symmetric cases

- PhysicsInternational Journal of Modern Physics B
- 2022

Local available quantum correlations (LAQC), as defined by Mundarain et al., are analyzed for two-qubit X states with local Bloch vectors of equal magnitude. Symmetric X-states are invariant under…

X states of the same spectrum and entanglement as all two-qubit states

- PhysicsQuantum Inf. Process.
- 2018

We present an explicit family of two-qubit X states with entanglement-preserving unitary equivalence to the set of general states; that is, for any spectrum–entanglement combination achievable by…

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

- Mathematics
- 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…

## References

SHOWING 1-10 OF 125 REFERENCES

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…

Evidence that All States Are Unitarily Equivalent to X States of the Same Entanglement

- Physics
- 2013

Strong numerical evidence is presented suggesting that all two-qubit mixed states are equivalent to X states by a single entanglement-preserving unitary (EPU) transformation, so that the concurrence…

Relative entropy of entanglement of two-qubit ‘X’ states

- Physics
- 2010

Two closest single-qubit states could be diagonalised by the same unitary matrix, which helps to find the relative entropy of entanglement of a two-qubit ‘X’ state. We formulate two binary equations…

Entanglement of Formation of an Arbitrary State of Two Qubits

- Physics
- 1998

The entanglement of a pure state of a pair of quantum systems is defined as the entropy of either member of the pair. The entanglement of formation of a mixed state is defined as the minimum average…

Genuinely multipartite concurrence of N -qubit X matrices

- Physics
- 2012

We find an algebraic formula for the N-partite concurrence of N qubits in an X matrix. X matrices are density matrices whose only nonzero elements are diagonal or antidiagonal when written in an…

Volume of the set of separable states

- Physics
- 1998

The question of how many entangled or, respectively, separable states there are in the set of all quantum states is considered. We propose a natural measure in the space of density matrices %…

Concurrence versus purity: Influence of local channels on Bell states of two qubits

- Physics
- 2005

We analyze how a maximally entangled state of two qubits (e.g.,
the singlet $psi_s$) is affected by the action of local
channels described by completely positive maps $E$. We analyze
the concurrence…

Maximizing Genuine Multipartite Entanglement of N Mixed Qubits

- Physics
- 2013

Beyond the simplest case of bipartite qubits, the composite Hilbert space of multipartite systems is largely unexplored. In order to explore such systems, it is important to derive analytic…

Entanglement evolution in the presence of decoherence

- Physics
- 2005

The entanglement of two qubits, each defined as an effective two-level, spin 1/2 system, is investigated for the case that the qubits interact via a Heisenberg XY interaction and are subject to…

An explicit expression for the relative entropy of entanglement in all dimensions

- Physics
- 2011

The relative entropy of entanglement is defined in terms of the relative entropy between an entangled state and its closest separable state (CSS). Given a multipartite-state on the boundary of the…